Benchmarking the integration of hexagonal boron nitride crystals and thin films into graphene-based van der Waals heterostructures
Taoufiq Ouaj Christophe Arnold Jon Azpeitia Sunaja Baltic Julien Barjon Jose Cascales Huanyao Cun David Esteban Mar Garcia-Hernandez Vincent Garnier Subodh K. Gautam Thomas Greber Said Said Hassani Adrian Hemmi Ignacio Jimenéz Catherine Journet Paul Kögerler Annick Loiseau Camille Maestre Marvin Metzelaars Philipp Schmidt Christoph Stampfer Ingrid Stenger Philippe Steyer Takashi Taniguchi Bérangère Toury Kenji Watanabe Bernd Beschoten




 
2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany

 
GEMaC, UVSQ, CNRS, Université Paris Saclay, France

 
Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain


2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany

 
GEMaC, UVSQ, CNRS, Université Paris Saclay, France


Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain


Physik-Institut, University of Zürich, Zürich, Switzerland


Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain


Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain


INSA Lyon, Universite Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510,69621 Villeurbanne, France

 
GEMaC, UVSQ, CNRS, Université Paris Saclay, France


Physik-Institut, University of Zürich, Zürich, Switzerland

 
GEMaC, UVSQ, CNRS, Université Paris Saclay, France


Physik-Institut, University of Zürich, Zürich, Switzerland


Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain


Universite Claude Bernard Lyon 1, CNRS, LMI UMR 5615, Villeurbanne, F-69100, France

 
Institute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, Germany
Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich, 52425 Jülich, Germany


Université Paris Saclay, ONERA, CNRS, Laboratoire d’Etude des Microstructures, 92322 Chatillon France


Universite Claude Bernard Lyon 1, CNRS, LMI UMR 5615, Villeurbanne, F-69100, France


2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany
Institute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, Germany


2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany


2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany
Peter Grünberg Institute (PGI-9) Forschungszentrum Jülich, 52425 Jülich, Germany

 
GEMaC, UVSQ, CNRS, Université Paris Saclay, France

 
INSA Lyon, Universite Claude Bernard Lyon 1, CNRS, MATEIS, UMR5510,69621 Villeurbanne, France


Research Center for Materials Nanoarchitectonics, National Institute for Materials Science,  1-1 Namiki, Tsukuba 305-0044, Japan


Universite Claude Bernard Lyon 1, CNRS, LMI UMR 5615, Villeurbanne, F-69100, France


Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan

 
bernd.beschoten@physik.rwth-aachen.de
2nd Institute of Physics and JARA-FIT, RWTH Aachen University, 52074 Aachen, Germany


§ ABSTRACT 
  We present a benchmarking protocol that combines the characterization of boron nitride (BN) crystals and films with the evaluation of the electronic properties of graphene on these substrates.
  
  Our study includes hBN crystals grown under different conditions (atmospheric pressure high temperature, high pressure high temperature, pressure controlled furnace) and scalable BN films deposited by either chemical or physical vapor deposition (CVD or PVD). 
  
  We explore the complete process from boron nitride growth, over its optical characterization by time-resolved cathodoluminescence (TRCL), to the optical and electronic characterization of graphene by Raman spectroscopy after encapsulation and Hall bar processing.
  Within our benchmarking protocol we achieve a homogeneous electronic performance within each Hall bar device through a fast and reproducible processing routine.
  
  We find that a free exciton lifetime of 1   ns measured on as-grown hBN crystals by TRCL is sufficient to achieve high graphene room temperature charge carrier mobilities of 80,000   cm^2/(Vs) at a carrier density of |n| = 1e12  cm^-2, while respective exciton lifetimes around 100   ps yield mobilities up to 30,000   cm^2/(Vs).
  
  For scalable PVD-grown BN films, we measure carrier mobilities exceeding 10,000   cm^2/(Vs) which correlates with a graphene Raman 2D peak linewidth of 22   cm^-1.  
  
  Our work highlights the importance of the Raman 2D linewidth of graphene as a critical metric that effectively assesses the interface quality (i.e. surface roughness) to the BN substrate, which directly affects the charge carrier mobility of graphene.
  
  Graphene 2D linewidth analysis is suitable for all BN substrates and is particularly advantageous when TRCL or BN Raman spectroscopy cannot be applied to specific BN materials such as amorphous or thin films. This underlines the superior role of spatially-resolved spectroscopy in the evaluation of BN crystals and films for the use of high-mobility graphene devices. 
  





Benchmarking the integration of hexagonal boron nitride crystals and thin films into graphene-based van der Waals heterostructures
    Bernd Beschoten
    September 9, 2024
==================================================================================================================================





§ INTRODUCTION



Boron nitride (BN) with its remarkable thermal stability, chemical inertness and robust mechanical properties has long been used for various applications <cit.>.

It has been demonstrated that hexagonal boron nitride (hBN) is of particular importance for applications in 2D material systems, exhibiting properties crucial for photonics and optoelectronics, such as efficient deep UV emissions <cit.> and quantum photonics capabilities <cit.>.

The high thermal conductivity <cit.>, the large electronic bandgap <cit.>, and the ultra-flat and inert surface <cit.> are important prerequisites for the use as a substrate for other 2D materials or for interface engineering <cit.>.

2D materials encapsulated in hBN allow for record-breaking charge carrier mobilites in graphene <cit.>, high electronic and optical quality in transition metal dichalcogenides (TMDs) <cit.> or, for example, bilayer graphene quantum devices with ultra-clean tunable bandgaps <cit.>.


In fundamental research, hBN flakes exfoliated from bulk crystals grown either at high temperature and high pressure (HPHT) <cit.> or at atmospheric pressure and high temperature (APHT) <cit.> are employed for high-quality device fabrication due to their superior crystal quality. 

The synthesis of high-quality hBN crystals in a pressure-controlled furnace (PCF) is a recent development that offers new opportunities for improving  material quality <cit.>.

hBN single crystals are small, a few millimeters at most, and therefore do not meet industrial manufacturing requirements. The transition of BN from the use in fundamental research to industrial applications requires process development capable of providing large area single crystal or polycrystalline films that meet both device requirements and high volume production needs. 

Techniques like chemical vapor deposition (CVD) <cit.>, metal-organic CVD (MOCVD) <cit.>, molecular beam epitaxy (MBE) <cit.>, 
and physical vapor deposition (PVD) <cit.> are under development, offering potential platforms for BN substrates with sufficient interface and/or bulk qualities for the desired technological applications.

Recently, amorphous (or nanocrystalline) boron nitride (aBN), has gained interest due to its ability to be grown at room temperature on arbitrary substrates <cit.> and its low dielectric constant <cit.>.

Especially the full encapsulation of CVD-grown graphene in direct-grown aBN was recently reported to have promising electronic properties, showing its potential as a scalable substrate for graphene and other 2D materials <cit.>.

The evolving diversity of available BN substrates – from high-quality hBN crystals to hBN/aBN films – underlines the need for comparable and meaningful characterization methods of both the crystal quality itself and the ability to be used as substrate in van der Waals heterostructures.

To assess the crystal quality, BN is mostly investigated by cathodoluminescence (CL) <cit.>, photoluminescence (PL) <cit.> or Raman spectroscopy <cit.>.

Raman spectroscopy gives a rapid and non-invasive way to extract the quality of BN films and therefore is an indispensable tool to efficiently monitor the parameter tuning during optimization of growth processes.

On the other side, CL measurements and especially time-resolved cathodoluminescence (TRCL) measurements yield a much more sensitive way to evaluate the crystal quality and to gain a deeper understanding of the type of crystal defects <cit.>.

Here, the free exciton lifetime, which is limited by exciton-defect scattering, yields a sensitive benchmark for the bulk crystal quality.

However, CL measurements are not suitable for most scalable BN growth approaches as they are only applicable to crystalline and thick (>10 μ m) hBN.

While these evaluations are highly important for benchmarking the quality of hBN crystals for optical applications with hBN as the active layer, methods to evaluate the surface quality become equally important when used as a substrate <cit.>.

For example, correlations between the amount or type of defects and the surface roughness seem possible but remain a topic under investigation <cit.>.


Graphene, due to its exceptional high charge carrier mobility, is one of the most interesting 2D materials to be used in combination with BN.

Additionally to the interest due to its electronic properties, graphene is highly sensitive to charge disorder and surface roughness of the substrate, drastically limiting the device performance <cit.>.

Due to both, its huge potential for future high-mobility applications and its high sensitivity to the underlying substrate, the evaluation of graphene itself on the substrate of interest is an appealing way to investigate the suitability of various BN films or crystals as a substrate for 2D materials.

Spatially-resolved confocal Raman microscopy on graphene encapsulated in BN provides a very powerful and sensitive way to directly assess strain, doping, and nm-strain variations <cit.> and directly link it to the electronic properties extracted from charge transport measurements on Hall bar devices <cit.>.


Here, we present a comprehensive evaluation of various BN substrates and present a benchmarking protocol covering the characterization of the BN as well as the evaluation of the electronic properties of exfoliated graphene on these BN substrates.

Our study includes the growth of both high-quality hBN crystals grown via APHT or in a PCF and the growth of scalable BN films via PVD or CVD (section II).

We extract the free exciton lifetime from TRCL measurements to compare the crystal quality of BN crystals and evaluate both exfoliated flakes and films via Raman spectroscopy (section III).

Using exfoliated graphene, we fabricated dry-transferred devices on the BN substrates to assess the interface quality via spatially-resolved Raman spectroscopy (section IV).

To establish reliable benchmarks we focus on the full width at half maximum (FWHM) of the graphene Raman 2D peak, which we identify as the most sensitive benchmark for an early-stage evaluation of the suitability for a diverse set of BN substrates (section V).

Following a newly developed fabrication scheme, with a focus on rapid processing, we build Hall bar structures (section VI) to extract the charge carrier mobility at different charge carrier densities (section VII).

We demonstrate that graphene encapsulated in APHT hBN crystals compares in electronic quality to graphene encapsulated in HPHT-grown hBN crystals, reaching room temperature charge carrier mobilities around 80,000   cm^2/(Vs) at a charge carrier density of n=1e12  cm^-2.

Importantly, we identify a free exciton lifetime of above 1   ns to be sufficient to achieve these high charge carrier mobilities and of 100   ps for charge carrier mobilities up to 30,000   cm^2/(Vs).

Specifically, we demonstrate that graphene on PVD-grown nanocrystalline boron nitride with a graphene 2D peak FWHM below 22   cm^-1 consistently yields charge carrier mobilities exceeding 10,000   cm^2/(Vs). 

This underscores the potential of PVD-grown BN films as scalable substrates for high-mobility graphene devices.



§ GROWTH AND PREPARATION OF BORON NITRIDE


In Fig. <ref> the growth and preparation conditions of hBN crystals (APHT and PCF growth) and of BN thin films (PVD and CVD growth) are summarized. 



 §.§ Atmospheric Pressure and High Temperature (APHT)

The hBN crystals in this study were grown from an iron flux (at RWTH) or chromium-nickel (at RWTH and GEMaC) flux via the APHT method
(see Ref. <cit.> for details on the growth at RWTH).

A schematic illustration of the growth setup is shown in Fig. <ref>(a).


The boron source is either boron powder (RWTH) mixed with the metal pieces or a pyrolytic BN crucible (GEMaC).

The system is first  annealed at high temperature under a continuous gas flow of either H_2 and Ar (RWTH) or N_2 (GEMaC) to minimize contaminations with oxygen and carbon. 

The hBN crystal growth is started upon introduction of N_2 while maintaining a constant pressure. 

After a soaking phase at high temperature to saturate the metal flux with B and N, the furnace is cooled down to a lower temperature at a slow rate (typically between 0.5^∘C/h and 4^∘C/h). 

The system is then quickly quenched down to room temperature. 

The resulting thick hBN crystal layer is firmly attached to the underlying metal ingot, as seen in Fig. <ref>(a) (right upper panel). 

The hBN crystal sheet can be detached from the metal ingot by immersion in hydrochloric acid at room temperature, see the detached crystal sheet in the lower right panel of Fig. <ref>(a).

This step does not affect the quality of the hBN crystals and simplifies the further processing of the hBN crystals for exfoliation and subsequent dry-transfer <cit.>.
 


 §.§ Growth in a pressure-controlled furnace (PCF)

In the PCF method, hBN crystals are grown from the liquid phase of Li_3BN_2-BN at high temperature <cit.>. 

The Li_3BN_2 powder is pre-synthesized from Li_3N (Sigma Aldrich, purity  > 99.5%) <cit.> and mixed with commercial hBN powder (20 wt% hBN and 80 wt% Li_3BN_2) in a molybdenum crucible. 

Since Li_3BN_2 is very sensitive to air and moisture, the growth preparation is performed under inert conditions and careful handling is necessary throughout the whole process. 

Both, hBN powder and crucibles are pre-treated at 1200^∘C under vacuum and an Ar/H_2 gas mix to remove potential contaminations. 

The growth is performed in a pressure-controlled furnace (PCF) <cit.> (schematically shown in Fig. <ref>(b)) during a fast cooling after a dwelling time of 2 hours at 1800^∘C and a pressure of 180 MPa under Ar atmosphere. 

The temperature and the pressure are increased at a rate of 100^∘C/min and 10 MPa/min. 

The chamber is initially purged three times (Ar filling followed by pumping) to remove oxygen and moisture.

The sample obtained is an ingot composed of hBN crystals embedded in a solidified Li_3BN_2 matrix. 

Li_3BN_2 dissolution is then performed to retrieve individual crystals. 

They show a lateral size ranging from several hundreds of micrometers to few millimeters, exemplary shown in Fig. <ref>(b), in the right image.

The crystals have been previously used  as encapsulants for TMDs and graphene to obtain optical and electronic devices <cit.>.







 §.§ Chemical Vapor Deposition (CVD)

For the growth of hBN layers, Pt(111) thin films with a thickness of 500  nm were prepared on sapphire wafers <cit.>. 

The hBN films were grown via CVD in an ultra-high vacuum cold-wall chamber for wafers up to 4-inch <cit.>. 

Prior to all hBN preparations, the Pt/sapphire substrates were cleaned by a series of argon sputtering, O_2 exposure and annealing cycles to 1200  K until sharp Pt(111) (1×1) LEED patterns were observed. 

Subsequently, hBN layers were prepared at temperatures above 1000   K with borazine (HBNH)_3 as precursor with a partial pressure of 10^-7 mbar (Fig. <ref>(c)). 

The quality of grown hBN layers were evaluated with scanning low energy electron diffraction (x-y LEED), x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The reported thickness is derived from XPS intensity values.


The transfer procedure employs the electrochemical “bubbling” method <cit.>.

First, the hBN/Pt(111) sample was spin-coated with 4   wt % polymethyl methacrylate (PMMA) (495   K).

Then we put the PMMA/hBN/Pt sample as working electrode and a Pt wire as counter electrode in a 1.0 M KCl solution. 

A negative voltage between -3  V and -5   V was applied to the sample to delaminate the hBN/PMMA film from the substrate. 

The delaminated hBN/PMMA film was then rinsed in ultrapure water (Milli-Q Advantage A10) and transferred onto a clean 280   nm Si/SiO_2 substrate with gold markers. 

In the next step, the PMMA was removed via a sequence of acetone/ethanol baths and gradual annealing in air at temperatures up to 600   K for 3  h (see transferred BN film in Fig. <ref>(c)).



 §.§ Physical Vapor Deposition (PVD)

Thin nanocrystalline BN films are grown via physical vapor deposition using an ion beam assisted deposition process (IBAD-PVD).

The films exhibit hexagonal bonding structure, as assessed by X-ray absorption near edge spectroscopy (XANES) <cit.> but lack of x-ray diffraction.

The films were grown directly on Si/SiO_2 wafers with an oxide thickness of 285   nm and pre-defined Cr/Au marker.

The growth was performed at room temperature using nitrogen gas and a solid boron source.

The IBAD process consisted in the interaction of a directional beam of 500   eV nitrogen ions from a Kaufman source, with concurrent boron atoms from an electron beam evaporator.

The growth setup is schematically depicted in Fig. <ref>(d).

The N-ion and B-atom fluxes were carefully tuned to obtain stoichiometric BN and avoid other B_xN_y phased and bonding configurations <cit.>.

The thickness of the resulting BN film is 30   nm and homogenously covers the whole wafer, as shown in Fig. <ref>(d).



§ CATHODOLUMINESENCE AND RAMAN SPECTROSCOPY ON BN CRYSTALS AND FILMS


The as-grown hBN crystals (APHT and PCF) are examined by means of TRCL measurements and spatially-resolved confocal Raman microscopy. 

Raman spectroscopy offers a fast and non-invasive tool to spatially probe optical phonons and their lifetimes, which provide a measure of the crystallinity of hBN <cit.>.

Time-resolved cathodoluminescence (TRCL) measurements allow to determine the lifetimes of the free excitons, which are strongly affected by scattering with defects, providing a valuable and sensitive tool to locally probe the crystal quality of hBN crystals.



 §.§ Cathodoluminescence





TRCL measurements were performed on isolated bulk hBN crystals. For each supplier (GEMaC, RWTH, LMI), crystals from multiple growth batches were investigated. The deep UV spectra were recorded at room temperature in a JEOL7001F field-emission-gun scanning electron microscope (SEM) coupled to a Horiba Jobin-Yvon cathodoluminescence (CL) detection system, as described in detail in earlier works <cit.>. 

To allow for time resolution, a custom-built fast-beam blanker was installed inside the SEM column, as described in <cit.>. 

The dynamics of the free exciton population is captured by measuring the time-dependent CL intensity in a wavelength range of 215 ± 7.5   nm with a temporal resolution of 100   ps. 

This spectral range corresponds to the main luminescence feature of high quality hBN crystals.

The 215   nm CL signal results from the indirect exciton recombination assisted via optical phonons. 

To focus on bulk properties and minimize surface recombinations, the electron beam acceleration voltage was set to 15  kV <cit.>.

The current was maintained at a low value of 85  pA to prevent nonlinear effects <cit.>. 

An exemplary TRCL measurement for each type of hBN crystal investigated is shown in Fig. <ref>. 

At t=0, the luminescence peak intensity is normalized to 1, to allow for better  comparison of the time evolution. 

The free exciton lifetime τ_CL is extracted by fitting the initial decay curve with an exponential function.

We obtain τ = 0.15   ns, 1.67   ns and 3.32   ns for PCF (LMI), APHT (RWTH) and APHT (GEMaC) crystals, respectively.

Statistical evaluation (mean and standard deviation) across different growth batches and spatial positions on the crystals yielded τ = (0.11 ± 0.07)   ns, (1.4 ± 0.3)   ns   and   (3.0 ± 0.4)   ns for 22, 13 and 8 measured areas on PCF (LMI), APHT (RWTH) and APHT (GEMaC), respectively. 

We emphasize the need for statistical evaluation due to notable crystal-to-crystal variations. 


The variation in free exciton lifetimes is associated with differences in defect densities in the crystals.

We note that APHT-grown crystals exhibit lifetimes similar to those produced via the HPHT method <cit.> which is consistent with a low defect density. In contrast, PCF-grown crystals show significantly shorter lifetimes. The higher defect density could  


result from vacancies, impurities, or structural anomalies, which all may affect the free lifetime.

The variations in lifetimes, even within crystals grown by the same method, highlights the need for careful crystal selection for specific experiments or applications.

Understanding these defect-induced changes in the optical properties is crucial for the further development of hBN applications in optoelectronics and quantum technology.

The benchmarking of hBN crystals via TRCL also sets the stage for understanding their role as substrates in graphene-based devices.

The observed variation in the exciton lifetime of hBN grown by the different methods is expected to correlate with the electronic quality of encapsulated 2D materials. 

Its impact on the charge carrier mobility in hBN/graphene/hBN Hall bar devices will be detailed further below. 




 §.§ Confocal Raman spectroscopy

Raman spectroscopy is a practical and widely used optical probe for characterizing both hBN crystals and thin films.

Its advantage of accessibility makes it an important tool for monitoring the effect of changes in the growth parameters on the crystal quality of BN.

The primary benchmark for assessing the crystal quality of hBN via Raman spectroscopy is the FWHM Γ_E_2g of the E_2g Raman peak, which correlates with the lifetime τ_E_2g of optical phonons corresponding to intralayer vibrations of B and N atoms <cit.>.

The contributions to the phonon linewidth in hBN with a natural isotopic content of boron originate primarily from isotopic disorder-induced scattering, anharmonic phonon decay, or impurity scattering <cit.>.

Thus, in hBN with the same crystal structure and isotope distribution, the variations in FWHM are mainly due to the degree of disorder in the crystal <cit.>.

Changes in bond lengths due to increased defect density or not-purely sp^2-hybridized bonds might also impact the FWHM, as these factors contribute to averaging effects over phonons of different frequencies.

Typically, high quality hBN crystals grown via HPHT or APHT exhibit a FWHM around 8   cm^-1 <cit.>.

For thin BN films this value can increase up to 40   cm^-1 <cit.>. 





  §.§.§ Experimental setup

Raman measurements were conducted using a commercial confocal micro-Raman setup (WITec alpha 300R) at room temperature.

We utilized a 532  nm excitation wavelength, a laser power of  2  mW and a 100× magnification objective with a numerical aperture of 0.9.

The inelastically scattered light was collected through a fibre (core diameter 100  μ m) and sent to a CCD through a half meter spectrometer equipped with a 1200    lines/mm grating.

For linewidth analysis of high-quality hBN crystals, we employed a grating with 2400   lines/mm.



  §.§.§ hBN crystals

We start by exfoliating thin hBN flakes from the bulk crystals using tape (Ultron 1007R) onto  Si/SiO_2 wafer with a 90   nm oxide layer and observe similar distribution of thicknesses and lateral sizes for flakes from all crystal suppliers. 

Flakes with thicknesses between 20  nm and 40  nm were selected based on their color contrast towards the substrate <cit.>, as these thicknesses are optimal for building state-of-the-art hBN-encapsulated graphene devices. 

In Figs. <ref>(a)-(c), we present optical images of representative flakes from the three suppliers ((a) for APHT (RWTH), (b) for APHT (GEMaC), and (c) for PCF (LMI)). 

All flakes look similar in terms of contamination or thickness homogeneity.

The FWHM of the E_2g peak is extracted by fitting a single Lorentzian function to the individual Raman spectra.

Spatially-resolved maps of the FWHM are shown in Fig. <ref>(d)-(f).

A respective single Raman spectrum at a representative position, along with the corresponding histogram to the FWHM map, are shown in Figs. <ref> (g)-(i). 


There is a narrow hBN Raman peak around 1365   cm^-1 for all flakes.

The maps in Figs. <ref> (d)-(f) reveal a homogenous and narrow distribution of the FWHM, suggesting uniform crystal quality throughout the exfoliated flakes.

A closer inspection of the statistical distribution (insets of (g)-(i)), reveals a Gaussian distribution of the FWHM around 8   cm^-1, demonstrating high crystallinity for all flakes.

These values are comparable to previous studies on APHT or HPHT grown hBN <cit.>.

Interestingly, we observe no significant difference in the Raman FWHM between PCF and APHT crystals. This observation seems surprising since the CL lifetime of the PCF-grown hBN flakes is more than an order of magnitude shorter than the respective lifetimes of the APHT-grown hBN crystals (see Fig. <ref>). It is, however, important to emphasize again that main contributions to the E_2g peak's FWHM in natural hBN results from isotopic disorder <cit.>, that is typically the same for all. While isotopic disorder is generally the same for all hBN crystals, variations in defect type and density can significantly vary between different growth methods. Our studies suggest that the presence of crystal defects in high-quality hBN crystals can barely be probed by Raman spectroscopy. Analyzing the lifetimes of free excitons, on the other hand, offers a significantly more sensitive tool for the local probing of crystal defects.


 











  §.§.§ BN films

We next evaluate boron nitride films, which are either grown directly on the Si/SiO_2 substrate (PVD) or grown by means of CVD and then wet-transferred to a Si/SiO_2 substrate.

In the case of boron nitride films, cathodoluminescence measurements are not feasible, mainly due to the small thickness of the films.

An optical image of the PVD-grown film is shown in Fig. <ref>(a).

We observe a homogeneously grown film over the entire wafer with some spots where the BN is damaged.

In Fig. <ref>(b) we additionally show a Raman spectrum at a representative position.

In contrast to the previously shown Raman spectra of flakes from exfoliated hBN crystals, we do not observe a single narrow Raman peak.

Instead, a broad response ranging from 1100   cm^-1 to 1600   cm^-1 is observed.

This can be related to the amorphous nature of the BN film, which leads to a strong broadening of the Raman peak  due to the inclusion of nanocrystalline regions within the BN film <cit.>.

The broadening may also result from random strain effects <cit.>. They lead to an averaging of different bond lengths between the atoms resulting in a statistical averaging of the Raman response due to variations in the phonon frequencies.

As the PVD grown BN films will later be used as a substrate for graphene, we next explore their surface roughness by atomic force microscopy (AFM).

Figure <ref>(c) displays an AFM image for a small region of the sample shown in Fig. <ref>(a).

A root mean square (RMS) roughness of 0.2   nm is extracted from this map.

This low value is in line with RMS values 
of hBN and the 2D semiconductor WSe_2, which have proven to be ideal substrates for graphene <cit.>. 



In Fig. <ref>(d) we show an optical image of the CVD grown BN film which was transferred on SiO_2. 

Due to the wet-transfer process and because multiple layers of hBN are transferred on top of each other, the BN film does not have a homogenous thickness. 

From XPS measurements we estimate an average thickness of 3 layers of hBN. 

The Raman spectrum at a representative position is shown in Fig. <ref>(e) together with a histogram of the distribution of the FWHM in panel (f).

We observe a well-defined hBN Raman peak at ω_E_2g = 1365   cm^-1 with a FHWM of Γ_E_2g = 34   cm^-1.

The large FWHM is in striking contrast to the previously discussed crystals but comparable to other BN films shown in literature <cit.>. 

We attribute the large FWHM to the wet transfer procedure and the remaining PMMA residues on the transferred BN film. 


To conclude the pre-characterization of BN crystals and films, we note that there is no common method which is either sensitive enough or applicable to all forms of BN, i.e. crystals and films.

Especially, for nanocrystalline or amorphous BN films, which are recognized as potential substrates for scaled devices, the usual characterization methods are not feasible.

We therefore proceed with the evaluation of graphene in contact with BN, by using graphene as a sensitive detector for the suitability of the underlying BN/hBN substrate for charge transport.



§ DRY-TRANSFER OF GRAPHENE ENCAPSULATED IN BN

The next step in the benchmarking protocol is to build van der Waals heterostructures using BN material to fully encapsulate graphene. The substrate quality of BN is then explored by probing the electronic properties of graphene using both spatially-resolved Raman spectroscopy and charge transport measurements. 

For the stacking of the heterostructures we start by exfoliating hBN and graphene flakes onto 90  nm Si/SiO_2. 

The flakes are searched and classified using a home-built automatic flake detection tool <cit.>. 

Suitable flakes with a thickness between 20 and 40 nm are identified and stacked on top of each other using standard dry-transfer methods with  poly(bisphenol A carbonate) (PC) film on top of a drop-shaped polydimethylsiloxane (PDMS) stamping tool <cit.>. 

The stacking process is schematically depicted in Fig. <ref>. 

For the benchmarking of hBN crystals (APHT and PCF), graphene is picked up using hBN flakes, which were exfoliated from their respective bulk crystals while for the evaluation of BN films the graphene is picked up by exfoliated HPHT-grown hBN (Figs. <ref>(b)-(d)).  

In the next step, the hBN/graphene half stack is either transferred onto corresponding hBN crystal flakes (Figs. <ref>(f)-(g)) or placed onto the BN films (Fig. <ref>(e)).

The protection of graphene from the top by an hBN crystal is important to ensure heterostructures of comparable quality and exclude influences on the graphene quality and device performance that can be caused by chemicals or airborne contaminations <cit.> during the subsequent processing steps.


Optical microscope images of the finished stacks are shown in Fig. <ref>(a)-(e). 

The lateral size of the stacks is limited by the size of the exfoliated hBN and graphene flakes. 

Within this project, we characterized in total over 40 dry-transferred samples to obtain a statistical evaluation of the various BN substrate and to exclude sample-to-sample variations. 




§ RAMAN SPECTROSCOPY ON BN-GRAPHENE HETEROSTRUCTURES




 §.§ Extraction of strain, strain variations and doping

We first give an overview on the key concepts of graphene-based Raman spectroscopy.

Figure <ref>(a) shows a typical Raman spectrum of graphene encapsulated in hBN crystals. 

Three prominent peaks are typically observed corresponding to the above analyzed hBN E_2g peak and the graphene G and 2D peak. 

The G peak in graphene results from out-of-phase in-plane vibrations of two carbon atoms of the two sublattices and involves phonons from the Γ-point, whereas the double resonant 2D peak corresponds to a breathing mode, involving phonons near the K-point <cit.>.
 

A crucial and sensitive quantity for the evaluation of the electronic properties of graphene is the FWHM of the 2D peak, which is directly connected to the extent of nm-scale strain variations within the laser spot <cit.> and therefore also contains information on the roughness of the substrate <cit.>. 

As strain variations locally break the hexagonal symmetry of the lattice, a vector potential is induced which in turn leads to an increased probability of backscattering of electrons in charge transport leading to a reduced charge carrier mobility <cit.>. 

The 2D FWHM is therefore the main quantity of interest in our study as it directly connects the interface quality given by the BN with the electronic quality of the adjacent graphene sheet.


The G and 2D peak are both susceptible to strain as well as doping <cit.> and the 2D peak position is additionally influenced by dielectric screening from the environment <cit.>, which is, however, not relevant in the scope of this study. 

To separate the effects of strain and doping from spatially-resolved Raman maps, the positions of the 2D and G peak are plotted against each other, as illustrated in Fig. <ref>(b). 

Since the two peaks shift differently as function of doping and strain, the slopes of the distributions can be used to qualitatively evaluate the type of disorder in the system (strain and/or doping). 

A distribution parallel to the strain axis has a slope of 2.2 and is connected to biaxial strain whereas a distribution along the doping axis has a slope ranging between 0.3 and 0.7 depending on both their charge carrier type and the substrate <cit.>.
 



 §.§ Results of spatially-resolved Raman spectroscopy

Raman measurements were performed with the same setup as for the characterization of the hBN crystals and films, using a grating of 1200 lines/mm.




Figures <ref>(f)-(j) show Raman maps of the graphene 2D linewidth for the regions highlighted with black dashed rectangles in the optical images in Figs. <ref>(a)-(e) for each BN source, respectively. 

The corresponding histograms are shown in Figs. <ref>(k)-(o) of a selected region of interest, highlighted with a dashed rectangle in the corresponding panel in Figs. <ref>(f)-(j).

The color scale is the same for all maps. 

Regions of a higher 2D linewidth within a stack may either result from bubbles (hydrocarbons) that are trapped at the interface between hBN and graphene or may be related to regions with multilayers. 

Residual hydrocarbons most likely originate from tape residues during  exfoliation or from the polymer used for  stacking <cit.>. The latter is a commonly known challenge when using  polymer-based dry-transfer techniques.

We observe the formation of bubbles for all stacks produced in this study.


Comparison of the contamination-free regions of the 2D FWHM maps reveals the lowest Γ_2D values for graphene on APHT-hBN (Figs. <ref>(f)-(g)), followed by PCF-grown crystals (Fig. <ref>(h)) and than the BN films (Figs. <ref>(i)-(j)).

The corresponding histograms in Figs. <ref>(k)-(o) enable the quantitative evaluation of the 2D FWHM maps.

The maximum of the statistical distribution ranges from 16.5   cm^-1 for APHT-grown crystals, over 18   cm^-1 for PCF-grown crystals to values larger than 20   cm^-1 for BN films.

We identify the peak position of the 2D linewidth distribution as a robust and sensitive quantity to evaluate the interface quality of the underlying BN, in line with previous works <cit.>.  

We conclude that the degree of strain variations in graphene is lowest for the APHT hBN crystals, which shows that they have the highest interface quality (flatness) among the studied BN. 



The respective ω_2D vs ω_G scatter plots are shown in Fig. <ref>(p)-(t), where the color code corresponds to the FWHM of the 2D peak.

For the stack presented in the first row of Fig. <ref> we chose a region with a spatially homogeneous and low 2D FWHM. The corresponding 2D vs G peak position distribution shows a strong clustering along the 2.2 strain axis indicating very small strain variations and negligible doping.

For the sample in the second row, the distribution with the lowest 2D linewidth (blue data points) is again mainly distributed along the strain axis. However, areas with inclusion (bubbles) exhibit larger 2D linewidths (green, yellow and reddish color) with a distribution outside the strain axis, which is probably due to larger doping.

The effect of doping on the peak positions is most clearly seen for the PVD-grown BN shown in the fourth row of Fig. <ref>.

The peak positions show a curved distribution that results from both strain and doping.


To go beyond the evaluation of the comparison of representative examples, we plot the graphene 2D linewidth of high-quality regions of all evaluated samples in a combined histogram in Fig. <ref>.

For the APHT-grown crystals we observe narrow distributions of the graphene 2D linewidth with the maximum at 16.5   cm^-1, demonstrating  an excellent and reproducible interface quality between graphene and hBN  over a number of 20 different heterostructures with hBN crystals taken from different batches. 

The histogram distribution of the PCF-crystals shows a broader distribution ranging from 17.5   cm^-1 to 19   cm^-1 indicating a larger amount of strain variations, and when evaluating different stacks, we additionally observe a larger sample-to sample variation in the 2D linewidth distribution.

While the analysis of the free exciton lifetime τ_CL in Fig. <ref> shows slightly shorter lifetimes for RWTH-APHT crystals compared to the GEMaC-APHT crystals there are no differences in the amount of nm-strain variations of encapsulated graphene as inferred from Raman spectroscopy. In contrast, the broader and shifted graphene 2D linewidth distribution of heterostacks fabricated by the PCF crystals seems to be related to their shorter exciton lifetimes. 

As the graphene 2D linewidth is connected to nm-strain variations caused by the roughness of the substrate surface, we conclude that the defect concentration in the PCF-grown crystals is so high that it affects the electronic properties of graphene.


Further, this quantity allows us to compare various substrates independent on their crystal nature to each other. 




§ PROCESSING INTO HALL BAR STRUCTURES


We next determine the key quantity of interest, the charge carrier mobility of graphene, and link it to the Raman 2D linewidths of graphene and the free exciton lifetimes of the BN substrate.

For this purpose, the fabricated heterostructures are patterned into Hall bar devices and electrically contacted to perform gate-dependent charge transport measurements.

For this study, we established a reproducible fabrication process yielding a high homogeneity of the electronic quality of graphene within a device as well as a high throughput of functioning contacts. 

For all devices we applied the same fabrication routine. 


A simplified overview of the various processing steps is shown in Fig. <ref>(e). 

First, the Hall bar structure is defined by electron beam lithography (EBL) (step 1). 

Subsequently, 30   nm aluminum (Al) is deposited using electron beam evaporation with a rate of 0.1   nm/s (step 2) and after lift-off we remain with the final Hall-bar structure protected by the Al hard mask (step 3).

The structure is subsequently etched using atomic layer etching (Oxford Plasma Pro 100) using Ar/SF_6 with a flow rate of 5/20 sccm and HF power of 50   W and a 5s oxygen etch pulse. 

The Al is chemically removed using tetramethylammonium hydroxide (TMAH) (step 4). 

The contacts to the Hall bar are defined in a second EBL step (step 5) and 5  nm/70  nm of Cr/Au is evaporated, with a rate of 0.2   nm/s and 0.5   nm/s (step 6). 

An optical microscope image of a representative, structured and contacted device is shown in Fig. <ref>(b). 


At this point, it is important to note that we have taken particular care to minimize the time between the individual processing steps. 

The etching, the subsequent second lithography step and the evaporation of Cr/Au was performed within the same day. 

By fabricating many devices, we have clear evidence that the time window between etching into the Hall bar structure where we expose the edges of graphene to air and the deposition of the side contacts to graphene should be minimized. For all devices, this time window was below 4   h.



 §.§ Influence of processing on the electronic properties of graphene


In this section we discuss the impact of the Hall bar processing onto the mechanical and electronic quality of the devices by using spatially-resolved Raman spectroscopy.

In Fig. <ref> we show a representative device PCF (LMI), with an optical image of the stack in panel (a) and the final device in panel (b). 

Figures <ref>(c) and (d) depict spatially-resolved Raman maps of the graphene 2D linewidth of the heterostructure before and after processing, respectively. 

The black rectangle in Fig. <ref>(c) illustrates the region chosen for the Hall-bar patterning, and only the Raman data from this region are used for comparison with the final Hall bar.

The respective histogram is shown in Fig. <ref>(f) (green data).

A comparison of the two maps in Figs. <ref>(c) and (d) shows: (i) an overall increases in the Raman 2D FWHM in the center of the Hall bar, which leads to a shift of the respective histogram (red data in Fig. <ref>(f)) towards higher wavenumbers and (ii) a strong increase in linewidth towards the edges of the Hall bar (reddish color in Fig. <ref>(d) that is seen as a tail in the histogram extending to values above 20 cm^-1. 

This finding could be linked to mechanical stress that occurs during the fabrication steps.

The different temperatures in the fabrication process, e.g. after baking the resist for lithography or during etching, can lead to stress due to the different thermal expansion coefficients of the materials within the stack and the substrate.


Considering the Raman 2D and G peak positions in Fig. <ref>(g), we clearly observe a red shift of the positions along the 2.2 strain line for the stack after fabrication.

This cloud (red data points) has shifted towards phonon frequencies closer to the point related to that of "pristine" graphene <cit.>, suggesting that strain release may have occurred  during the device fabrication.

We only show one example here, but this finding is observed in many different samples, regardless of the type of BN used.

A more detailed investigation is beyond the scope of this paper and future works focusing on the monitoring of different fabrication steps are necessary to draw clearer conclusions.




 §.§ Room temperature charge carrier mobilities

The individual Hall bars with the different BN substrates were fabricated in heterostack regions of the lowest possible and homogeneous graphene Raman 2D FWHM (as an example, see black rectangle  in Fig. <ref>(c)).

All charge transport measurements were taken at room temperature under vacuum. 

An example of a Hall bar with the measurement scheme is depicted in Fig. <ref>(a). 


We use an AC voltage V_0 = 1  V at a frequency of 77 Hz and a series resistance of R_P=1 MΩ to pass a constant current of I = 1 μ A between the source and drain contact. 

The four-terminal voltage drop is measured for different regions along the graphene transport channel, labelled as V_xx in Fig. <ref>(a) for the upper region as an example .  

This voltage drop converts to the  resistivity (1/conductivity) following ρ = 1 /σ = W/L · V_xx/I, where L is the distance between the contacts and W the width of the transport channel. 


Figure <ref>(b) shows the gate dependent resistivity and conductivity for an APHT device (red traces in panel (d)). 

For all measured regions, the conductivity σ reaches at least 400   e^2/h at large gate voltages, i.e. large charge carrier densities, which is mainly limited by electron-phonon scattering <cit.>. 

Importantly, and in contrast to previous studies, we observe homogeneous transport properties along the graphene channel and a high yield of functioning contacts (larger than 90 %).

While the electronic homogeneity is likely due to the pre-selection of the regions via Raman mapping, we link the high throughput of functioning contacts to the decreased time between the etching (i.e. exposing of graphene contact areas) and evaporation of the Cr/Au.




The charge carrier density n is extracted from Hall effect measurements. It is connected to the gate voltage by n=α (V_G-V_G^0), where V_G^0 is the position of the charge neutrality point, i.e. the voltage of the Dirac peak, and α is the gate lever arm.  

The carrier mobilities μ = σ/(ne) of graphene with the different BN substrates are shown in Figs. <ref>(c)-(h) for each BN source individually. As a reference, we show transport data for a Hall bar device where we used HPHT hBN (NIMS) (see Fig. <ref>(c)).  

For each device, multiple regions were measured. Traces of the same color are from different regions of the same device. There are only small variations in transport characteristics within a single device but also between different devices fabricated from the same BN source.  

This finding further confirms a robust and reliable processing routine, which was developed as part of the benchmarking study. 

For devices built by APHT hBN we measure the highest charge carrier mobilities exceeding 80,000  cm^2(Vs)^-1 at a charge carrier density of |n|=1e12  cm^-2 (see Figs. <ref>(c) and (d)).  

These values are fully in line with state of the art high-mobility graphene devices using HPHT hBN <cit.> (see also Fig. <ref>(c)) or APHT hBN from other sources <cit.>. 

We therefore highlight the viability of APHT hBN crystals as a true alternative to HPHT hBN crystals, for high-performance graphene devices.

For the PCF-grown crystals in Fig. <ref>(f), we observe a  carrier mobility of up to 30,000  cm^2(Vs)^-1 at |n|=1e12  cm^-2. 

The lower charge carrier mobility of graphene encapsulated in PCF-grown hBN, when compared to APHT hBN, is fully consistent with our two previous observations, a shorter free exciton lifetime and a higher 2D linewidth of graphene encapsulated in PCF-grown hBN crystals.

The relation between an increase in graphene 2D linewidth and a decrease in charge carrier mobility is understood in terms of increased electron backscattering  due to the stronger nm-strain variations <cit.>. 

For the PVD grown BN film (Fig. <ref>(g)) we extract charge carrier mobilities over 10,000  cm^2(Vs)^-1 at  n=1e12  cm^-2, while we achieve mobilities around 4,000  cm^2(Vs)^-1 at  n=1e12  cm^-2 for the CVD-grown and wet-transferred films (Fig. <ref>(h)).



§ DISCUSSION



In Fig. <ref>, we summarize the main results of the BN benchmarking study: (a) room temperature charge carrier mobility vs carrier density and carrier mobilities at  n=1e12  cm^-2 vs (b) free exciton lifetime of hBN, (c) Γ_E_2g of hBN and (d) graphene 2D linewidth of all BN substrates. 
In Fig. <ref>(a) we show the transport traces for the region of highest mobility for each device shown in Figs. <ref>(c) to (h). 

As mentioned above, APHT grown hBN allows for equally high graphene mobilities as achieved for HPHT-grown hBN crystals. 

These hBN sources are of high relevance for many research groups, who are interested in high quality hBN crystals for fundamental research. 

The PCF-grown crystals, following another route of hBN crystal growth, allow for mobilities up to 30,000  cm^2(Vs)^-1 at  n=1e12  cm^-2, demonstrating the great potential of new synthesis routes for the production of high quality hBN crystals.  

One aim of this synthesis route is to satisfy the increasing demand of hBN crystals from many research groups. 

However, these approaches to grow high quality hBN crystals are not scalable, because they cannot be easily combined with technologically relevant substrates and the desired thicknesses can only be achieved via mechanical exfoliation. 

Scalable methods for growing BN are therefore needed to unlock the full potential of graphene-based electronics in future nanoelectronic devices. 


In this respect, the PVD growth method is most promising because (i) it allows the growth of tens of nanometer thick films with very low surface roughness and (ii) it can be deposited directly onto Si/SiO_2 substrates. The large BN thickness screens disorder from the silicon substrates, while the deposition on the target substrates prevents the need for large scale layer transfer. Most importantly, the PVD-grown BN allows for room temperature carrier mobilities of graphene exceeding 10,000  cm^2(Vs)^-1 at  n=1e12  cm^-2. We conclude that the low temperature PVD growth process of BN on SiO_2 is a promising platform for achieving scalable BN substrates not only for graphene, but also for other 2D materials. 


If we compare the charge carrier mobility with the Raman 2D FWHM we see a clear trend of decreasing mobility with increasing 2D FWHM. 

This is in good agreement with the finding that nm-scale strain variations are the limitation for high charge carrier mobilities
<cit.> and shows that the graphene Raman 2D FWHM is a good measure for benchmarking as used in the ICE TS 62607-6-6 key control characteristics <cit.>. 

Whereas we do not find a correlation between the FWHM of the hBN Raman peak and the charge carrier mobility we observe a clear correlation between the CL lifetime and the mobility, as shown in Fig. <ref>(b). 

We observe that we need CL lifetimes of over 1   ns to achieve charge carrier mobilities in the range of 80,000  cm^2(Vs)^-1 at  n=1e12  cm^-2. 

For CL lifetimes of 100   ps we achieve charge carrier mobilities up to 30,000  cm^2(Vs)^-1. 

The interface quality is therefore connected to the hBN crystal quality, i.e. the number of defects, in a sensitive way.



In conclusion, we have presented a comprehensive study of the electronic properties of graphene on different boron nitride substrates using a newly developed reproducible processing routine.

We have shown the complete process from boron nitride synthesis, over its  optical characterization, to the optical and electronic characterization of graphene after encapsulation and Hall bar fabrication. 

We identify the Raman spectrum of BN as a valuable measure for distinguishing hBN in the high crystallinity limit from BN films, but we also point out the limitations of the Raman analysis when comparing high-quality hBN crystals. 

In this respect, time-resolved cathodoluminescence has a clear advantage over Raman spectroscopy when evaluating the as-grown quality of hBN, as the probing of the free exciton lifetime is very sensitive to the defects in hBN. 

The fabrication of graphene-based heterostructures on BN  substrates demonstrates the high sensitivity of graphene to the environment, allowing graphene to be used as a sensitive detector of the substrate and interface quality.

Variations in the quality of the graphene-BN interface are directly reflected in a broadening of the graphene Raman 2D peak. This broadening has a direct effect on the carrier mobility, i.e. the mobility is inversely proportional to the peak of the 2D linewidth distribution of graphene. It is therefore advisable to characterize the Raman 2D linewidth distribution of the finished heterostructure prior to any processing.      

In terms of benchmarking we find that a CL lifetime larger than 1 ns is sufficient for high hBN crystal quality and high graphene-hBN interface qualities with low nm strain variations in graphene, which is essential for fundamental studies on highest mobility graphene-based devices. 

For scalable approaches we see that a graphene Raman 2D linewidth  below 22  cm^-1 is necessary to achieve charge carrier mobilities over 10,000  cm^2(Vs)^-1. 
PVD-grown BN films, therefore, offer a promising platform for scalable high mobility graphene devices. 




§ DATA AVAILABILITY

The data supporting the findings of this study are available in a Zenodo repository under, https://doi.org/10.5281/zenodo.13684712.


§ ACKNOWLEDGEMENTS

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 881603 (Graphene Flagship), T.O., S.B., P.S, C.S., and B.B. acknowledge support from the European Research Council (ERC) under grant agreement No. 820254, and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - Cluster of Excellence Matter and Light for Quantum Computing (ML4Q) EXC 2004/1 - 390534769. H.Y.C. was supported by a SPARK grant of the Swiss National Science Foundation (Grant No. CRSK-2_220582). A.H. acknowledges a Forschungskredit of the University of Zürich (Grant No. FK-20-206 114). 
K.W. and T.T. acknowledge support from the JSPS KAKENHI (Grant Numbers 21H05233 and 23H02052) and World Premier International Research Center Initiative (WPI), MEXT, Japan.












114
fxundefined [1]
 ifx#1

fnum [1]
 #1firstoftwo
 secondoftwo
 
fx [1]
 #1firstoftwo
 secondoftwo
 





noop [0]secondoftwo

ref[1]@startlink#1@href
href[1]#1@endlink
anitize@url [0]`
12`$12`&12`#12`1̂2`_12`%12
startlink[1]
endlink[0]

rl [1]href #1












@bib@innerbibempty

[Meng et al.(2019)Meng, Wang, Cheng, Gao, and Zhang]Meng2019Feb
  author author J. Meng, author D. Wang, author L. Cheng, author M. Gao, and author X. Zhang, title title Recent progress in synthesis, properties, and applications of hexagonal boron nitride-based heterostructures, https://doi.org/10.1088/1361-6528/aaf301 journal journal Nanotechnology volume 30, pages 074003. (year 2019), https://arxiv.org/abs/30523895 30523895 NoStop
[Schuéé et al.(2016a)Schuéé, Stenger, Fossard, Loiseau, and Barjon]Schue2016Dec
  author author L. Schuéé, author I. Stenger, author F. Fossard, author A. Loiseau, and author J. Barjon, title title Characterization methods dedicated to nanometer-thick hBN layers, https://doi.org/10.1088/2053-1583/4/1/015028 journal journal 2D Mater. volume 4, pages 1 (year 2016a)NoStop
[Backes et al.(2020)Backes, Abdelkader, Alonso, Andrieux-Ledier, Arenal, Azpeitia, Balakrishnan, Banszerus, Barjon, Bartali, Bellani, Berger, Berger, Ortega, Bernard, Beton, Beyer, Bianco, Bøggild, Bonaccorso, Barin, Botas, Bueno, Carriazo, Castellanos-Gomez, Christian, Ciesielski, Ciuk, Cole, Coleman, Coletti, Crema, Cun, Dasler, De Fazio, Díez, Drieschner, Duesberg, Fasel, Feng, Fina, Forti, Galiotis, Garberoglio, García, Garrido, Gibertini, Göölzhääuser, Góómez, Greber, Hauke, Hemmi, Hernandez-Rodriguez, Hirsch, Hodge, Huttel, Jepsen, Jimenez, Kaiser, Kaplas, Kim, Kis, Papagelis, Kostarelos, Krajewska, Lee, Li, Lipsanen, Liscio, Lohe, Loiseau, Lombardi, Lóópez, Martin, Martín, Martínez, Martin-Gago, Martínez, Marzari, Mayoral, McManus, Melucci, Mééndez, Merino, Merino, Meyer, Miniussi, Miseikis, Mishra, Morandi, Munuera, Muññoz, Nolan, Ortolani, Ott, Palacio, Palermo, Parthenios, Pasternak, Patane, Prato, Prevost, Prudkovskiy, Pugno, Rojo, Rossi, Ruffieux, Samorì, Schuéé, Setijadi, Seyller, Speranza, Stampfer, Stenger, Strupinski, Svirko, Taioli, Teo, Testi, Tomarchio, Tortello, Treossi, Turchanin, Vazquez, Villaro, Whelan, Xia, Yakimova, Yang, Yazdi, Yim, Yoon, Zhang, Zhuang, Colombo, Ferrari, and Garcia-Hernandez]Backes2020Jan
  author author C. Backes, author A. M. Abdelkader, author C. Alonso, author A. Andrieux-Ledier, author R. Arenal, author J. Azpeitia, author N. Balakrishnan, author L. Banszerus, author J. Barjon, author R. Bartali, author S. Bellani, author C. Berger, author R. Berger, author M. M. B. Ortega, author C. Bernard, author P. H. Beton, author A. Beyer, author A. Bianco, author P. Bøggild, author F. Bonaccorso, author G. B. Barin, author C. Botas, author R. A. Bueno, author D. Carriazo, author A. Castellanos-Gomez, author M. Christian, author A. Ciesielski, author T. Ciuk, author M. T. Cole, author J. Coleman, author C. Coletti, author
  L. Crema, author H. Cun, author D. Dasler, author D. De Fazio, author N. Díez, author S. Drieschner, author G. S. Duesberg, author R. Fasel, author X. Feng, author A. Fina, author S. Forti, author C. Galiotis, author G. Garberoglio, author J. M. García, author J. A. Garrido, author
  M. Gibertini, author A. Göölzhääuser, author J. Góómez, author T. Greber, author F. Hauke, author A. Hemmi, author I. Hernandez-Rodriguez, author A. Hirsch, author S. A. Hodge, author Y. Huttel, author P. U. Jepsen, author I. Jimenez, author U. Kaiser, author T. Kaplas, author H. Kim, author A. Kis, author K. Papagelis, author K. Kostarelos, author A. Krajewska, author K. Lee, author C. Li, author H. Lipsanen, author A. Liscio, author M. R. Lohe, author A. Loiseau, author L. Lombardi, author M. F. Lóópez, author O. Martin, author C. Martín, author L. Martínez, author J. A. Martin-Gago, author J. I. Martínez, author N. Marzari, author ÁÁ. Mayoral, author J. McManus, author M. Melucci, author J. Mééndez, author C. Merino, author P. Merino, author A. P. Meyer, author E. Miniussi, author V. Miseikis, author N. Mishra, author V. Morandi, author C. Munuera, author R. Muññoz, author H. Nolan, author L. Ortolani, author A. K. Ott, author I. Palacio, author V. Palermo, author J. Parthenios, author I. Pasternak, author A. Patane, author M. Prato, author H. Prevost, author V. Prudkovskiy, author N. Pugno, author T. Rojo, author
  A. Rossi, author P. Ruffieux, author P. Samorì, author L. Schuéé, author E. Setijadi, author T. Seyller, author G. Speranza, author C. Stampfer, author I. Stenger, author W. Strupinski, author Y. Svirko, author S. Taioli, author K. B. K. Teo, author M. Testi, author F. Tomarchio, author
  M. Tortello, author E. Treossi, author A. Turchanin, author E. Vazquez, author E. Villaro, author P. R. Whelan, author Z. Xia, author R. Yakimova, author S. Yang, author G. R. Yazdi, author C. Yim, author D. Yoon, author X. Zhang, author X. Zhuang, author L. Colombo, author A. C. Ferrari, and author
  M. Garcia-Hernandez, title title Production and processing of graphene and related materials, https://doi.org/10.1088/2053-1583/ab1e0a journal journal 2D Mater. volume 7, pages 022001 (year 2020)NoStop
[Naclerio and Kidambi(2023)]Naclerio2023Feb
  author author A. E. Naclerio and author P. R. Kidambi, title title A Review of Scalable Hexagonal Boron Nitride (h-BN) Synthesis for Present and Future Applications, https://doi.org/10.1002/adma.202207374 journal journal Adv. Mater. volume 35, pages 2207374 (year 2023)NoStop
[Watanabe et al.(2004)Watanabe, Taniguchi, and Kanda]Watanabe2004Jun
  author author K. Watanabe, author T. Taniguchi, and author H. Kanda, title title Direct-bandgap properties and evidence for ultraviolet lasing of hexagonal boron nitride single crystal, https://doi.org/10.1038/nmat1134 journal journal Nat. Mater. volume 3, pages 404 (year 2004)NoStop
[Kubota et al.(2007)Kubota, Watanabe, Tsuda, and Taniguchi]Kubota2007Aug
  author author Y. Kubota, author K. Watanabe, author O. Tsuda, and author T. Taniguchi, title title Deep Ultraviolet Light-Emitting Hexagonal Boron Nitride Synthesized at Atmospheric Pressure, https://doi.org/10.1126/science.1144216 journal journal Science volume 317, pages 932 (year 2007)NoStop
[Bourrellier et al.(2016)Bourrellier, Meuret, Tararan, Stééphan, Kociak, Tizei, and Zobelli]Bourrellier2016Jul
  author author R. Bourrellier, author S. Meuret, author A. Tararan, author O. Stééphan, author M. Kociak, author L. H. G. Tizei, and author A. Zobelli, title title Bright UV Single Photon Emission at Point Defects in h-BN, https://doi.org/10.1021/acs.nanolett.6b01368 journal journal Nano Lett. volume 16, pages 4317 (year 2016)NoStop
[Grosso et al.(2017)Grosso, Moon, Lienhard, Ali, Efetov, Furchi, Jarillo-Herrero, Ford, Aharonovich, and Englund]Grosso2017Sep
  author author G. Grosso, author H. Moon, author B. Lienhard, author S. Ali, author D. K. Efetov, author M. M. Furchi, author P. Jarillo-Herrero, author M. J. Ford, author I. Aharonovich, and author D. Englund, title title Tunable and high-purity room temperature single-photon emission from atomic defects in hexagonal boron nitride, https://doi.org/10.1038/s41467-017-00810-2 journal journal Nat. Commun. volume 8, pages 1 (year
  2017)NoStop
[Martínez et al.(2016)Martínez, Pelini, Waselowski, Maze, Gil, Cassabois, and Jacques]Martinez2016Sep
  author author L. J. Martínez, author T. Pelini, author V. Waselowski, author J. R. Maze, author B. Gil, author G. Cassabois, and author V. Jacques, title title Efficient single photon emission from a high-purity hexagonal boron nitride crystal, https://doi.org/10.1103/PhysRevB.94.121405 journal journal Phys. Rev. B volume 94, pages 121405 (year 2016)NoStop
[Fournier et al.(2021)Fournier, Plaud, Roux, Pierret, Rosticher, Watanabe, Taniguchi, Buil, Quéélin, Barjon, Hermier, and Delteil]Fournier2021Jun
  author author C. Fournier, author A. Plaud, author S. Roux, author A. Pierret, author M. Rosticher, author K. Watanabe, author T. Taniguchi, author S. Buil, author X. Quéélin, author J. Barjon, author J.-P. Hermier, and author A. Delteil, title title Position-controlled quantum emitters with reproducible emission wavelength in hexagonal boron nitride, https://doi.org/10.1038/s41467-021-24019-6
  journal journal Nat. Commun. volume 12, pages 1 (year 2021)NoStop
[Lindsay and Broido(2011)]Lindsay2011Oct
  author author L. Lindsay and author D. A. Broido, title title Enhanced thermal conductivity and isotope effect in single-layer hexagonal boron nitride, https://doi.org/10.1103/PhysRevB.84.155421 journal journal Phys. Rev. B volume 84, pages 155421 (year 2011)NoStop
[Yuan et al.(2019)Yuan, Li, Lindsay, Cherns, Pomeroy, Liu, Edgar, and Kuball]Yuan2019May
  author author C. Yuan, author J. Li, author L. Lindsay, author D. Cherns, author J. W. Pomeroy, author S. Liu, author J. H. Edgar, and author M. Kuball, title title Modulating the thermal conductivity in hexagonal boron nitride via controlled boron isotope concentration, https://doi.org/10.1038/s42005-019-0145-5 journal journal Commun. Phys. volume 2, pages 1 (year 2019)NoStop
[Xue et al.(2011)Xue, Sanchez-Yamagishi, Bulmash, Jacquod, Deshpande, Watanabe, Taniguchi, Jarillo-Herrero, and LeRoy]Xue2011Apr
  author author J. Xue, author J. Sanchez-Yamagishi, author D. Bulmash, author P. Jacquod, author A. Deshpande, author K. Watanabe, author T. Taniguchi, author P. Jarillo-Herrero, and author B. J. LeRoy, title title Scanning tunnelling microscopy and spectroscopy of ultra-flat graphene on hexagonal boron nitride, https://doi.org/10.1038/nmat2968 journal journal Nat. Mater. volume 10, pages 282 (year 2011)NoStop
[Woods et al.(2014)Woods, Britnell, Eckmann, Ma, Lu, Guo, Lin, Yu, Cao, Gorbachev, Kretinin, Park, Ponomarenko, Katsnelson, Gornostyrev, Watanabe, Taniguchi, Casiraghi, Gao, Geim, and Novoselov]Woods2014Jun
  author author C. R. Woods, author L. Britnell, author A. Eckmann, author R. S. Ma, author J. C. Lu, author H. M. Guo, author X. Lin, author G. L. Yu, author Y. Cao, author R. V. Gorbachev, author A. V. Kretinin, author J. Park, author L. A. Ponomarenko, author M. I. Katsnelson, author Yu. N. Gornostyrev, author
  K. Watanabe, author T. Taniguchi, author C. Casiraghi, author H.-J. Gao, author A. K. Geim, and author K. S. Novoselov, title title Commensurate–incommensurate transition in graphene on hexagonal boron nitride, https://doi.org/10.1038/nphys2954 journal journal Nat. Phys. volume 10, pages 451 (year 2014)NoStop
[Britnell et al.(2012)Britnell, Gorbachev, Jalil, Belle, Schedin, Katsnelson, Eaves, Morozov, Mayorov, Peres, Castro Neto, Leist, Geim, Ponomarenko, and Novoselov]Britnell2012Mar
  author author L. Britnell, author R. V. Gorbachev, author R. Jalil, author B. D. Belle, author F. Schedin, author M. I. Katsnelson, author L. Eaves, author S. V. Morozov, author A. S. Mayorov, author N. M. R. Peres, author A. H. Castro Neto, author J. Leist, author A. K. Geim, author L. A. Ponomarenko, and author K. S. Novoselov,  title title Electron Tunneling through Ultrathin Boron Nitride Crystalline Barriers, https://doi.org/10.1021/nl3002205 journal journal Nano Lett. volume 12, pages 1707 (year 2012)NoStop
[Sharpe et al.(2019)Sharpe, Fox, Barnard, Finney, Watanabe, Taniguchi, Kastner, and Goldhaber-Gordon]Sharpe2019Aug
  author author A. L. Sharpe, author E. J. Fox, author A. W. Barnard, author J. Finney, author K. Watanabe, author T. Taniguchi, author M. A. Kastner, and author D. Goldhaber-Gordon, title title Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene, https://doi.org/10.1126/science.aaw3780 journal journal Science volume 365, pages 605 (year 2019)NoStop
[Tebbe et al.(2023)Tebbe, Schüütte, Watanabe, Taniguchi, Stampfer, Beschoten, and Waldecker]Tebbe2023Apr
  author author D. Tebbe, author M. Schüütte, author K. Watanabe, author T. Taniguchi, author C. Stampfer, author B. Beschoten, and author L. Waldecker, title title Tailoring the dielectric screening in WS_2 graphene heterostructures, https://doi.org/10.1038/s41699-023-00394-0 journal journal npj 2D Mater. Appl. volume 7, pages 1 (year 2023)NoStop
[Tebbe et al.(2024)Tebbe, Schüütte, Watanabe, Taniguchi, Stampfer, Beschoten, and Waldecker]Tebbe2024May
  author author D. Tebbe, author M. Schüütte, author K. Watanabe, author T. Taniguchi, author C. Stampfer, author B. Beschoten, and author L. Waldecker, title title Distance Dependence of the Energy Transfer Mechanism in WS_2-Graphene Heterostructures, https://doi.org/10.1103/PhysRevLett.132.196902 journal journal Phys. Rev. Lett. volume 132, pages 196902 (year 2024)NoStop
[Dean et al.(2010)Dean, Young, Meric, Lee, Wang, Sorgenfrei, Watanabe, Taniguchi, Kim, Shepard, and Hone]Dean2010Oct
  author author C. R. Dean, author A. F. Young, author I. Meric, author C. Lee, author L. Wang, author S. Sorgenfrei, author K. Watanabe, author T. Taniguchi, author P. Kim, author K. L. Shepard, and author J. Hone, title title Boron nitride substrates for high-quality graphene electronics, https://doi.org/10.1038/nnano.2010.172 journal journal Nat. Nanotechnol. volume 5, pages 722 (year
  2010)NoStop
[Wang et al.(2013)Wang, Meric, Huang, Gao, Gao, Tran, Taniguchi, Watanabe, Campos, Muller, Guo, Kim, Hone, Shepard, and Dean]Wang2013Nov
  author author L. Wang, author I. Meric, author P. Y. Huang, author Q. Gao, author Y. Gao, author H. Tran, author T. Taniguchi, author K. Watanabe, author L. M. Campos, author D. A. Muller, author J. Guo, author P. Kim, author J. Hone, author K. L. Shepard, and author C. R. Dean, title title One-Dimensional
  Electrical Contact to a Two-Dimensional Material, https://doi.org/10.1126/science.1244358 journal journal Science volume 342, pages 614 (year 2013)NoStop
[Banszerus et al.(2015)Banszerus, Schmitz, Engels, Dauber, Oellers, Haupt, Watanabe, Taniguchi, Beschoten, and Stampfer]Banszerus2015Jul
  author author L. Banszerus, author M. Schmitz, author S. Engels, author J. Dauber, author M. Oellers, author F. Haupt, author K. Watanabe, author T. Taniguchi, author B. Beschoten, and author C. Stampfer, title title Ultrahigh-mobility graphene devices from chemical vapor deposition on reusable copper, https://doi.org/10.1126/sciadv.1500222 journal journal Sci. Adv. volume 1, pages e1500222 (year 2015)NoStop
[Onodera et al.(2020)Onodera, Taniguchi, Watanabe, Isayama, Masubuchi, Moriya, and Machida]Onodera2020Jan
  author author M. Onodera, author T. Taniguchi, author K. Watanabe, author M. Isayama, author S. Masubuchi, author R. Moriya, and author T. Machida, title title Hexagonal Boron Nitride Synthesized at Atmospheric Pressure Using Metal Alloy Solvents: Evaluation as a Substrate for 2D Materials, https://doi.org/10.1021/acs.nanolett.9b04641 journal journal Nano Lett. volume 20, pages 735 (year 2020)NoStop
[Sonntag et al.(2020)Sonntag, Li, Plaud, Loiseau, Barjon, Edgar, and Stampfer]Sonntag2020Jun
  author author J. Sonntag, author J. Li, author A. Plaud, author A. Loiseau, author J. Barjon, author J. H. Edgar, and author C. Stampfer, title title Excellent electronic transport in heterostructures of graphene and monoisotopic boron-nitride grown at atmospheric pressure, https://doi.org/10.1088/2053-1583/ab89e5 journal journal 2D Mater. volume 7, pages 031009 (year 2020)NoStop
[Ouaj et al.(2023)Ouaj, Kramme, Metzelaars, Li, Watanabe, Taniguchi, Edgar, Beschoten, Köögerler, and Stampfer]Ouaj2023Sep
  author author T. Ouaj, author L. Kramme, author M. Metzelaars, author J. Li, author K. Watanabe, author T. Taniguchi, author J. H. Edgar, author B. Beschoten, author P. Köögerler, and author C. Stampfer, title title Chemically detaching hBN crystals grown at atmospheric pressure and high temperature for high-performance graphene devices, https://doi.org/10.1088/1361-6528/acf2a0 journal journal Nanotechnology volume 34, pages
  475703 (year 2023)NoStop
[Ajayi et al.(2017)Ajayi, Ardelean, Shepard, Wang, Antony, Taniguchi, Watanabe, Heinz, Strauf, Zhu, and Hone]Ajayi2017Jul
  author author O. A. Ajayi, author J. V. Ardelean, author G. D. Shepard, author J. Wang, author A. Antony, author T. Taniguchi, author K. Watanabe, author T. F. Heinz, author S. Strauf, author X.-Y. Zhu, and author J. C. Hone, title title Approaching the intrinsic photoluminescence linewidth in transition metal dichalcogenide monolayers, https://doi.org/10.1088/2053-1583/aa6aa1 journal journal 2D Mater. volume 4,  pages 031011 (year 2017)NoStop
[Ye et al.(2018)Ye, Waldecker, Ma, Rhodes, Antony, Kim, Zhang, Deng, Jiang, Lu, Smirnov, Watanabe, Taniguchi, Hone, and Heinz]Ye2018Sep
  author author Z. Ye, author L. Waldecker, author E. Y. Ma, author D. Rhodes, author A. Antony, author B. Kim, author X.-X. Zhang, author M. Deng, author Y. Jiang, author Z. Lu, author D. Smirnov, author K. Watanabe, author T. Taniguchi, author J. Hone, and author T. F. Heinz, title title Efficient generation of
  neutral and charged biexcitons in encapsulated WSe_2 monolayers, https://doi.org/10.1038/s41467-018-05917-8 journal journal Nat. Commun. volume 9, pages 1 (year 2018)NoStop
[Raja et al.(2019)Raja, Waldecker, Zipfel, Cho, Brem, Ziegler, Kulig, Taniguchi, Watanabe, Malic, Heinz, Berkelbach, and Chernikov]Raja2019Sep
  author author A. Raja, author L. Waldecker, author J. Zipfel, author Y. Cho, author S. Brem, author J. D. Ziegler, author M. Kulig, author T. Taniguchi, author K. Watanabe, author E. Malic, author T. F. Heinz, author T. C. Berkelbach, and author A. Chernikov, title title Dielectric disorder in two-dimensional materials, https://doi.org/10.1038/s41565-019-0520-0 journal
  journal Nat. Nanotechnol. volume 14, pages 832 (year 2019)NoStop
[Cadiz et al.(2017)Cadiz, Courtade, Robert, Wang, Shen, Cai, Taniguchi, Watanabe, Carrere, Lagarde, Manca, Amand, Renucci, Tongay, Marie, and Urbaszek]Cadiz2017May
  author author F. Cadiz, author E. Courtade, author C. Robert, author G. Wang, author Y. Shen, author H. Cai, author T. Taniguchi, author K. Watanabe, author H. Carrere, author D. Lagarde, author M. Manca, author T. Amand, author P. Renucci, author S. Tongay, author X. Marie, and author B. Urbaszek,  title title Excitonic Linewidth Approaching the Homogeneous Limit in MoS_2-Based van der Waals Heterostructures, https://doi.org/10.1103/PhysRevX.7.021026 journal journal Phys. Rev. X volume 7, pages 021026 (year 2017)NoStop
[Ersfeld et al.(2020)Ersfeld, Volmer, Rathmann, Kotewitz, Heithoff, Lohmann, Yang, Watanabe, Taniguchi, Bartels, Shi, Stampfer, and Beschoten]Ersfeld2020May
  author author M. Ersfeld, author F. Volmer, author L. Rathmann, author L. Kotewitz, author M. Heithoff, author M. Lohmann, author B. Yang, author K. Watanabe, author T. Taniguchi, author L. Bartels, author J. Shi, author C. Stampfer, and author B. Beschoten, title title Unveiling Valley Lifetimes of Free Charge Carriers in Monolayer WSe_2, https://doi.org/10.1021/acs.nanolett.9b05138
  journal journal Nano Lett. volume 20, pages 3147 (year 2020)NoStop
[Shi et al.(2020)Shi, Shih, Gustafsson, Rhodes, Kim, Watanabe, Taniguchi, Papićć, Hone, and Dean]Shi2020Jul
  author author Q. Shi, author E.-M. Shih, author M. V. Gustafsson, author D. A. Rhodes, author B. Kim, author K. Watanabe, author T. Taniguchi, author Z. Papićć, author J. Hone, and author C. R. Dean, title title Odd- and even-denominator fractional quantum Hall states in monolayer WSe_2, https://doi.org/10.1038/s41565-020-0685-6 journal journal Nat. Nanotechnol. volume 15, pages 569 (year
  2020)NoStop
[Eich et al.(2018)Eich, Pisoni, Pally, Overweg, Kurzmann, Lee, Rickhaus, Watanabe, Taniguchi, Ensslin, and Ihn]Eich2018Aug
  author author M. Eich, author R. Pisoni, author A. Pally, author H. Overweg, author A. Kurzmann, author Y. Lee, author P. Rickhaus, author K. Watanabe, author T. Taniguchi, author K. Ensslin, and author T. Ihn, title title Coupled Quantum Dots in Bilayer Graphene, https://doi.org/10.1021/acs.nanolett.8b01859 journal journal Nano Lett. volume 18, pages 5042 (year 2018)NoStop
[Banszerus et al.(2018)Banszerus, Frohn, Epping, Neumaier, Watanabe, Taniguchi, and Stampfer]Banszerus2018Aug
  author author L. Banszerus, author B. Frohn, author A. Epping, author D. Neumaier, author K. Watanabe, author T. Taniguchi, and author C. Stampfer, title title Gate-Defined Electron–Hole Double Dots in Bilayer Graphene, https://doi.org/10.1021/acs.nanolett.8b01303 journal journal Nano Lett. volume 18, pages 4785 (year 2018)NoStop
[Icking et al.(2022)Icking, Banszerus, Wöörtche, Volmer, Schmidt, Steiner, Engels, Hesselmann, Goldsche, Watanabe, Taniguchi, Volk, Beschoten, and Stampfer]Icking2022Nov
  author author E. Icking, author L. Banszerus, author F. Wöörtche, author F. Volmer, author P. Schmidt, author C. Steiner, author S. Engels, author J. Hesselmann, author M. Goldsche, author K. Watanabe, author T. Taniguchi, author C. Volk, author B. Beschoten, and author C. Stampfer, title title Transport Spectroscopy of Ultraclean
  Tunable Band Gaps in Bilayer Graphene, https://doi.org/10.1002/aelm.202200510 journal journal Adv. Electron. Mater. volume 8, pages 2200510 (year 2022)NoStop
[Icking et al.(2024)Icking, Emmerich, Watanabe, Taniguchi, Beschoten, Lemme, Knoch, and Stampfer]Icking2024Sep
  author author E. Icking, author D. Emmerich, author K. Watanabe, author T. Taniguchi, author B. Beschoten, author M. C. Lemme, author J. Knoch, and author C. Stampfer, title title Ultrasteep Slope Cryogenic FETs Based on Bilayer Graphene, journal journal Nano Lett. volume 2024, https://doi.org/10.1021/acs.nanolett.4c02463 10.1021/acs.nanolett.4c02463 (year 2024)NoStop
[Taniguchi and Watanabe(2007)]Taniguchi2007May
  author author T. Taniguchi and author K. Watanabe, title title Synthesis of high-purity boron nitride single crystals under high pressure by using Ba–BN solvent, https://doi.org/10.1016/j.jcrysgro.2006.12.061 journal journal J. Cryst. Growth volume 303, pages 525 (year 2007)NoStop
[Zhigadlo(2014)]Zhigadlo2014Sep
  author author N. D. Zhigadlo, title title Crystal growth of hexagonal boron nitride (hBN) from Mg–B–N solvent system under high pressure, https://doi.org/10.1016/j.jcrysgro.2014.06.038 journal journal J. Cryst. Growth volume 402, pages 308 (year 2014)NoStop
[Fukunaga et al.(2022)Fukunaga, Nakano, and Taniguchi]Fukunaga2022Nov
  author author O. Fukunaga, author S. Nakano, and author T. Taniguchi, title title Experimental results on the high-pressure phase diagram of boron nitride, https://doi.org/10.35848/1347-4065/ac9dd5 journal journal Jpn. J. Appl. Phys. volume 61, pages 125502 (year 2022)NoStop
[Kubota et al.(2008)Kubota, Watanabe, Tsuda, and Taniguchi]Kubota2008Mar
  author author Y. Kubota, author K. Watanabe, author O. Tsuda, and author T. Taniguchi, title title Hexagonal Boron Nitride Single Crystal Growth at Atmospheric Pressure Using Ni-Cr Solvent, https://doi.org/10.1021/cm7028382 journal journal Chem. Mater. volume 20, pages 1661 (year 2008)NoStop
[Hoffman et al.(2014)Hoffman, Clubine, Zhang, Snow, and Edgar]Hoffman2014May
  author author T. B. Hoffman, author B. Clubine, author Y. Zhang, author K. Snow, and author J. H. Edgar, title title Optimization of Ni–Cr flux growth for hexagonal boron nitride single crystals, https://doi.org/10.1016/j.jcrysgro.2013.09.030 journal journal J. Cryst. Growth volume 393, pages 114 (year 2014)NoStop
[Edgar et al.(2014)Edgar, Hoffman, Clubine, Currie, and Jiang]Edgar2014Oct
  author author J. H. Edgar, author T. B. Hoffman, author B. Clubine, author M. Currie, and author H. X. Jiang, title title Characterization of bulk hexagonal boron nitride single crystals grown by the metal flux technique, https://doi.org/10.1016/j.jcrysgro.2014.06.006 journal journal J. Cryst. Growth volume 403, pages 110 (year 2014)NoStop
[Liu et al.(2017)Liu, He, Ye, Du, Lin, Jiang, Liu, and Edgar]Liu2017Sep
  author author S. Liu, author R. He, author Z. Ye, author X. Du, author J. Lin, author H. Jiang, author B. Liu, and author J. H. Edgar, title title Large-Scale Growth of High-Quality Hexagonal Boron Nitride Crystals at Atmospheric Pressure from an Fe–Cr Flux, https://doi.org/10.1021/acs.cgd.7b00871 journal journal Cryst. Growth Des. volume 17, pages 4932 (year 2017)NoStop
[Liu et al.(2018)Liu, He, Xue, Li, Liu, and Edgar]Liu2018Sep
  author author S. Liu, author R. He, author L. Xue, author J. Li, author B. Liu, and author J. H. Edgar, title title Single Crystal Growth of Millimeter-Sized Monoisotopic Hexagonal Boron Nitride, https://doi.org/10.1021/acs.chemmater.8b02589 journal journal Chem. Mater. volume 30, pages 6222 (year 2018)NoStop
[Zhang et al.(2019)Zhang, Xu, Zhao, Shao, and Wan]Zhang2019Nov
  author author S.-Y. Zhang, author K. Xu, author X.-K. Zhao, author Z.-Y. Shao, and author N. Wan, title title Improved hBN Single-Crystal Growth by Adding Carbon in the Metal Flux, https://doi.org/10.1021/acs.cgd.9b00712 journal journal Cryst. Growth Des. volume 19, pages 6252 (year 2019)NoStop
[Li et al.(2020a)Li, Yuan, Elias, Wang, Zhang, Ye, Huang, Kuball, Eda, Redwing, He, Cassabois, Gil, Valvin, Pelini, Liu, and Edgar]Li2020Jun
  author author J. Li, author C. Yuan, author C. Elias, author J. Wang, author X. Zhang, author G. Ye, author C. Huang, author M. Kuball, author G. Eda, author J. M. Redwing, author R. He, author G. Cassabois, author B. Gil, author P. Valvin, author T. Pelini, author B. Liu, and author
  J. H. Edgar, title title Hexagonal Boron Nitride Single Crystal Growth from Solution with a Temperature Gradient, https://doi.org/10.1021/acs.chemmater.0c00830 journal journal Chem. Mater. volume 32, pages 5066 (year 2020a)NoStop
[Li et al.(2021a)Li, Wang, Zhang, Elias, Ye, Evans, Eda, Redwing, Cassabois, Gil, Valvin, He, Liu, and Edgar]Li2021Apr
  author author J. Li, author J. Wang, author X. Zhang, author C. Elias, author G. Ye, author D. Evans, author G. Eda, author J. M. Redwing, author G. Cassabois, author B. Gil, author P. Valvin, author R. He, author B. Liu, and author J. H. Edgar, title title Hexagonal Boron Nitride Crystal Growth from Iron, a Single Component Flux, https://doi.org/10.1021/acsnano.1c00115 journal journal ACS Nano volume 15, pages 7032 (year 2021a)NoStop
[Li et al.(2020b)Li, Elias, Ye, Evans, Liu, He, Cassabois, Gil, Valvin, Liu, and Edgar]Li2020
  author author J. Li, author C. Elias, author G. Ye, author D. Evans, author S. Liu, author R. He, author G. Cassabois, author B. Gil, author P. Valvin, author B. Liu, and author J. H. Edgar, title title Single crystal growth of monoisotopic hexagonal boron nitride from a Fe–Cr flux, https://doi.org/10.1039/D0TC02143A journal journal J. Mater. Chem. C volume 8, pages 9931 (year
  2020b)NoStop
[Li et al.(2021b)Li, Wen, Tan, Li, Li, Huang, Tian, Yao, Liao, Yu, Liu, Li, Guo, Huang, Gao, Wang, Bai, and Liu]Li2021
  author author Y. Li, author X. Wen, author C. Tan, author N. Li, author R. Li, author X. Huang, author H. Tian, author Z. Yao, author P. Liao, author S. Yu, author S. Liu, author Z. Li, author J. Guo, author Y. Huang, author P. Gao, author L. Wang, author S. Bai, and author L. Liu, title title Synthesis of centimeter-scale high-quality polycrystalline hexagonal boron nitride films from Fe fluxes, https://doi.org/10.1039/D1NR02408F journal journal Nanoscale volume 13, pages 11223 (year 2021b)NoStop
[Zhang et al.(2021)Zhang, Yang, Wang, Zhong, and Chen]Zhang2021May
  author author N. Zhang, author N. Yang, author W. Wang, author X. Zhong, and author X. Chen, title title Growth of hexagonal boron nitride crystals at atmospheric pressure from CuCr flux, https://doi.org/10.1016/j.jcrysgro.2021.126074 journal journal J. Cryst. Growth volume 562, pages 126074 (year 2021)NoStop
[Li et al.(2020c)Li, Garnier, Steyer, Journet, and Toury]Li2020Feb
  author author Y. Li, author V. Garnier, author P. Steyer, author C. Journet, and author B. Toury, title title Millimeter-Scale Hexagonal Boron Nitride Single Crystals for Nanosheet Generation, https://doi.org/10.1021/acsanm.9b02315 journal journal ACS Appl. Nano Mater. volume 3, pages 1508 (year 2020c)NoStop
[Maestre et al.(2022)Maestre, Li, Garnier, Steyer, Roux, Plaud, Loiseau, Barjon, Ren, Robert, Han, Marie, Journet, and Toury]Maestre2022May
  author author C. Maestre, author Y. Li, author V. Garnier, author P. Steyer, author S. Roux, author A. Plaud, author A. Loiseau, author J. Barjon, author L. Ren, author C. Robert, author B. Han, author X. Marie, author C. Journet, and author B. Toury, title title From the synthesis of hBN crystals to their use as nanosheets in van der Waals
  heterostructures, https://doi.org/10.1088/2053-1583/ac6c31 journal journal 2D Mater. volume 9, pages 035008 (year 2022)NoStop
[Chubarov et al.(2013)Chubarov, Pedersen, Höögberg, Filippov, Engelbrecht, O'Connel, and Henry]Chubarov
  author author M. Chubarov, author H. Pedersen, author H. Höögberg, author S. Filippov, author J. Engelbrecht, author J. O'Connel, and author A. Henry, title title Characterization of Boron Nitride thin films, in https://doi.org/10.1109/CLEOPR.2013.6600222 booktitle 2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR) (publisher IEEE, year 2013) pp. pages 2013–04NoStop
[Jang et al.(2016)Jang, Hong, Hyun, Yoon, Kim, Jeong, Shin, Park, Wong, Kwak, Park, Yu, Choi, Mishchenko, Withers, Novoselov, Lim, and Shin]Jang2016May
  author author A.-R. Jang, author S. Hong, author C. Hyun, author S. I. Yoon, author G. Kim, author H. Y. Jeong, author T. J. Shin, author S. O. Park, author K. Wong, author S. K. Kwak, author N. Park, author K. Yu, author E. Choi, author A. Mishchenko, author F. Withers, author K. S. Novoselov,
  author H. Lim, and author H. S. Shin, title title Wafer-Scale and Wrinkle-Free Epitaxial Growth of Single-Orientated Multilayer Hexagonal Boron Nitride on Sapphire, https://doi.org/10.1021/acs.nanolett.6b01051 journal journal Nano Lett. volume 16, pages 3360 (year 2016)NoStop
[Lee et al.(2018)Lee, Choi, Yun, Kim, Boandoh, Park, Shin, Ko, Lee, Kim, Lee, Kim, and Kim]Lee2018Nov
  author author J. S. Lee, author S. H. Choi, author S. J. Yun, author Y. I. Kim, author S. Boandoh, author J.-H. Park, author B. G. Shin, author H. Ko, author S. H. Lee, author Y.-M. Kim, author Y. H. Lee, author K. K. Kim, and author S. M. Kim, title title Wafer-scale single-crystal hexagonal boron nitride film via self-collimated grain formation, https://doi.org/10.1126/science.aau2132 journal journal Science volume 362, pages 817 (year 2018)NoStop
[Asgari et al.(2022)Asgari, Viti, Balci, Shinde, Zhang, Ramezani, Sharma, Meersha, Menichetti, McAleese, Conran, Wang, Tomadin, Ferrari, and Vitiello]Asgari2022Jul
  author author M. Asgari, author L. Viti, author O. Balci, author S. M. Shinde, author J. Zhang, author H. Ramezani, author S. Sharma, author A. Meersha, author G. Menichetti, author C. McAleese, author B. Conran, author X. Wang, author A. Tomadin, author A. C. Ferrari, and author M. S. Vitiello, title title
  Terahertz photodetection in scalable single-layer-graphene and hexagonal boron nitride heterostructures, https://doi.org/10.1063/5.0097726 journal journal Appl. Phys. Lett. volume 121, pages 031103 (year 2022)NoStop
[Calandrini et al.(2023)Calandrini, Voronin, Balci, Barra-Burillo, Bylinkin, Shinde, Sharma, Casanova, Hueso, Chuvilin, McAleese, Conran, Wang, Teo, Volkov, Ferrari, Nikitin, and Hillenbrand]Calandrini2023Nov
  author author E. Calandrini, author K. Voronin, author O. Balci, author M. Barra-Burillo, author A. Bylinkin, author S. M. Shinde, author S. Sharma, author F. Casanova, author L. E. Hueso, author A. Chuvilin, author C. McAleese, author B. R. Conran, author X. Wang, author K. Teo, author V. S. Volkov, author A. C.  Ferrari, author A. Y. Nikitin, and author R. Hillenbrand, title title Near- and Far-Field Observation of Phonon Polaritons in Wafer-Scale Multilayer Hexagonal Boron Nitride Prepared by Chemical Vapor Deposition, https://doi.org/10.1002/adma.202302045 journal journal Adv. Mater. volume 35, pages 2302045 (year 2023)NoStop
[Tailpied et al.(2024)Tailpied, Andrieux-Ledier, Fossard, Méérot, Decams, and Loiseau]Tailpied2024Aug
  author author L. Tailpied, author A. Andrieux-Ledier, author F. Fossard, author J.-S. Méérot, author J.-M. Decams, and author A. Loiseau, title title Ni(111) Substrate Engineering for the Epitaxial Chemical Vapor Deposition Growth of Wrinkle-Free Multilayer Rhombohedral Boron Nitride Films, journal journal Cryst. Growth Des. volume 2024, https://doi.org/10.1021/acs.cgd.4c00478 10.1021/acs.cgd.4c00478 (year 2024)NoStop
[Kobayashi and Akasaka(2008)]Kobayashi2008Nov
  author author Y. Kobayashi and author T. Akasaka, title title Hexagonal BN epitaxial growth on (0001) sapphire substrate by MOVPE, https://doi.org/10.1016/j.jcrysgro.2008.07.010 journal journal J. Cryst. Growth volume 310, pages 5044 (year 2008)NoStop
[Kobayashi et al.(2012)Kobayashi, Kumakura, Akasaka, and Makimoto]Kobayashi2012Apr
  author author Y. Kobayashi, author K. Kumakura, author T. Akasaka, and author T. Makimoto, title title Layered boron nitride as a release layer for mechanical transfer of GaN-based devices, https://doi.org/10.1038/nature10970 journal journal Nature volume 484, pages 223 (year 2012)NoStop
[Li et al.(2016)Li, Sundaram, El Gmili, Ayari, Puybaret, Patriarche, Voss, Salvestrini, and Ougazzaden]Li2016Jun
  author author X. Li, author S. Sundaram, author Y. El Gmili, author T. Ayari, author R. Puybaret, author G. Patriarche, author P. L. Voss, author J. P. Salvestrini, and author A. Ougazzaden, title title Large-Area Two-Dimensional Layered Hexagonal Boron Nitride Grown on Sapphire by Metalorganic Vapor Phase Epitaxy, https://doi.org/10.1021/acs.cgd.6b00398 journal journal Cryst. Growth Des. volume 16, pages 3409 (year 2016)NoStop
[Jeong et al.(2019)Jeong, Kim, Kim, Moon, Han, Lee, Okello, Song, Choi, and Kim]Jeong2019Apr
  author author H. Jeong, author D. Y. Kim, author J. Kim, author S. Moon, author N. Han, author S. H. Lee, author O. F. N. Okello, author K. Song, author S.-Y. Choi, and author J. K. Kim, title title Wafer-scale and selective-area growth of high-quality hexagonal boron nitride on Ni(111) by metal-organic chemical vapor deposition, https://doi.org/10.1038/s41598-019-42236-4 journal journal Sci. Rep. volume 9, pages 1 (year
  2019)NoStop
[Cho et al.(2016)Cho, Summerfield, Davies, Cheng, Smith, Mellor, Khlobystov, Foxon, Eaves, Beton, and Novikov]Cho2016Sep
  author author Y.-J. Cho, author A. Summerfield, author A. Davies, author T. S. Cheng, author E. F. Smith, author C. J. Mellor, author A. N. Khlobystov, author C. T. Foxon, author L. Eaves, author P. H. Beton, and author S. V. Novikov, title title Hexagonal Boron Nitride Tunnel Barriers Grown on Graphite by High Temperature Molecular Beam Epitaxy, https://doi.org/10.1038/srep34474 journal journal Sci. Rep. volume 6,  pages 1 (year 2016)NoStop
[Elias et al.(2019)Elias, Valvin, Pelini, Summerfield, Mellor, Cheng, Eaves, Foxon, Beton, Novikov, Gil, and Cassabois]Elias2019Jun
  author author C. Elias, author P. Valvin, author T. Pelini, author A. Summerfield, author C. J. Mellor, author T. S. Cheng, author L. Eaves, author C. T. Foxon, author P. H. Beton, author S. V. Novikov, author B. Gil, and author G. Cassabois, title title Direct band-gap crossover in epitaxial monolayer boron nitride, https://doi.org/10.1038/s41467-019-10610-5 journal journal Nat. Commun. volume 10, pages 1 (year 2019)NoStop
[Heilmann et al.(2020)Heilmann, Prikhodko, Hanke, Sabelfeld, Borgardt, and Lopes]Heilmann2020Feb
  author author M. Heilmann, author A. S. Prikhodko, author M. Hanke, author A. Sabelfeld, author N. I. Borgardt, and author J. M. J. Lopes, title title Influence of Proximity to Supporting Substrate on van der Waals Epitaxy of Atomically Thin Graphene/Hexagonal Boron Nitride Heterostructures, https://doi.org/10.1021/acsami.9b21490 journal journal ACS Appl. Mater. Interfaces volume 12, pages 8897 (year 2020)NoStop
[Rousseau et al.(2024)Rousseau, Plo, Valvin, Cheng, Bradford, James, Wrigley, Mellor, Beton, Novikov, Jacques, Gil, and Cassabois]Rousseau2024Mar
  author author A. Rousseau, author J. Plo, author P. Valvin, author T. S. Cheng, author J. Bradford, author T. S. S. James, author J. Wrigley, author C. J. Mellor, author P. H. Beton, author S. V. Novikov, author V. Jacques, author B. Gil, and author G. Cassabois, title title Spatially-resolved UV-C emission in epitaxial monolayer boron nitride, https://doi.org/10.1088/2053-1583/ad2f45
  journal journal 2D Mater. volume 11, pages 025026 (year 2024)NoStop
[Caretti and Jiméénez(2011a)]Caretti2011Aug
  author author I. Caretti and author I. Jiméénez, title title Composition and bonding structure of boron nitride B_1-xN_x thin films grown by ion-beam assisted evaporation, https://doi.org/10.1016/j.cplett.2011.06.001 journal journal Chem. Phys. Lett. volume 511, pages 235 (year 2011a)NoStop
[Jiméénez et al.(2012)Jiméénez, Torres, Caretti, Gago, and Albella]Jimenez2012Mar
  author author I. Jiméénez, author R. Torres, author I. Caretti, author R. Gago, and author J. M. Albella, title title A review of monolithic and multilayer coatings within the boron–carbon–nitrogen system by ion-beam-assisted deposition, https://doi.org/10.1557/jmr.2011.398 journal journal J. Mater. Res. volume 27, pages 743 (year 2012)NoStop
[Torres et al.(2014)Torres, Caretti, Serin, Brun, Radnóóczic, and Jiméénez]Torres2014Aug
  author author R. Torres, author I. Caretti, author V. Serin, author N. Brun, author G. Radnóóczic, and author I. Jiméénez, title title Reversed texture in nanometric carbon/boron nitride multilayers, https://doi.org/10.1016/j.carbon.2014.03.027 journal journal Carbon volume 74, pages 374 (year 2014)NoStop
[Hong et al.(2020)Hong, Lee, Lee, Lee, Ma, Kim, Yoon, Ihm, Kim, Shin, Kim, Jeon, Jeon, Kim, Lee, Lee, Antidormi, Roche, Chhowalla, Shin, and Shin]Hong2020Jun
  author author S. Hong, author C.-S. Lee, author M.-H. Lee, author Y. Lee, author K. Y. Ma, author G. Kim, author S. I. Yoon, author K. Ihm, author K.-J. Kim, author T. J. Shin, author S. W. Kim, author E.-c. Jeon, author H. Jeon, author J.-Y. Kim, author H.-I. Lee, author Z. Lee, author A. Antidormi, author S. Roche, author M. Chhowalla, author H.-J. Shin, and author H. S. Shin, title title Ultralow-dielectric-constant amorphous boron nitride, https://doi.org/10.1038/s41586-020-2375-9 journal journal Nature volume 582, pages 511 (year 2020)NoStop
[Sattari-Esfahlan et al.(2023)Sattari-Esfahlan, Kim, Hyun, Choi, Hwang, Kim, Park, and Lee]Sattari-Esfahlan2023Feb
  author author S. M. Sattari-Esfahlan, author H. G. Kim, author S. H. Hyun, author J.-H. Choi, author H. S. Hwang, author E.-T. Kim, author H. G. Park, and author J.-H. Lee, title title Low-Temperature Direct Growth of Amorphous Boron Nitride Films for High-Performance Nanoelectronic Device Applications, https://doi.org/10.1021/acsami.2c18706 journal journal ACS Appl. Mater. Interfaces volume 15, pages 7274 (year 2023)NoStop
[Martini et al.(2023)Martini, Miššeikis, Esteban, Azpeitia, Pezzini, Paletti, Ochapski, Convertino, Hernandez, Jimenez, and Coletti]Martini2023Aug
  author author L. Martini, author V. Miššeikis, author D. Esteban, author J. Azpeitia, author S. Pezzini, author P. Paletti, author M. W. Ochapski, author D. Convertino, author M. G. Hernandez, author I. Jimenez, and author C. Coletti, title title Scalable High-Mobility Graphene/hBN Heterostructures, https://doi.org/10.1021/acsami.3c06120 journal journal ACS Appl. Mater. Interfaces volume 15,  pages 37794 (year 2023)NoStop
[Schuéé et al.(2016b)Schuéé, Berini, Betz, Plaçais, Ducastelle, Barjon, and Loiseau]Schue2016Mar
  author author L. Schuéé, author B. Berini, author A. C. Betz, author B. Plaçais, author F. Ducastelle, author J. Barjon, and author A. Loiseau, title title Dimensionality effects on the luminescence properties of hBN, https://doi.org/10.1039/C6NR01253A journal journal Nanoscale volume 8, pages 6986 (year 2016b)NoStop
[Schuéé et al.(2019)Schuéé, Sponza, Plaud, Bensalah, Watanabe, Taniguchi, Ducastelle, Loiseau, and Barjon]Schue2019Feb
  author author L. Schuéé, author L. Sponza, author A. Plaud, author H. Bensalah, author K. Watanabe, author T. Taniguchi, author F. Ducastelle, author A. Loiseau, and author J. Barjon, title title Bright Luminescence from Indirect and Strongly Bound Excitons in h-BN, https://doi.org/10.1103/PhysRevLett.122.067401 journal journal Phys. Rev. Lett. volume 122, pages 067401 (year 2019)NoStop
[Roux et al.(2021)Roux, Arnold, Paleari, Sponza, Janzen, Edgar, Toury, Journet, Garnier, Steyer, Taniguchi, Watanabe, Ducastelle, Loiseau, and Barjon]Roux2021Oct
  author author S. Roux, author C. Arnold, author F. Paleari, author L. Sponza, author E. Janzen, author J. H. Edgar, author B. Toury, author C. Journet, author V. Garnier, author P. Steyer, author T. Taniguchi, author K. Watanabe, author F. Ducastelle, author A. Loiseau, and author J. Barjon, title title Radiative
  lifetime of free excitons in hexagonal boron nitride, https://doi.org/10.1103/PhysRevB.104.L161203 journal journal Phys. Rev. B volume 104, pages L161203 (year 2021)NoStop
[Cassabois et al.(2016)Cassabois, Valvin, and Gil]Cassabois2016Apr
  author author G. Cassabois, author P. Valvin, and author B. Gil, title title Hexagonal boron nitride is an indirect bandgap semiconductor, https://doi.org/10.1038/nphoton.2015.277 journal journal Nat. Photonics volume 10, pages 262 (year 2016)NoStop
[Rousseau et al.(2021)Rousseau, Ren, Durand, Valvin, Gil, Watanabe, Taniguchi, Urbaszek, Marie, Robert, and Cassabois]Rousseau2021Dec
  author author A. Rousseau, author L. Ren, author A. Durand, author P. Valvin, author B. Gil, author K. Watanabe, author T. Taniguchi, author B. Urbaszek, author X. Marie, author C. Robert, and author G. Cassabois, title title Monolayer Boron Nitride: Hyperspectral Imaging in the Deep Ultraviolet, https://doi.org/10.1021/acs.nanolett.1c02531 journal journal Nano Lett. volume 21, pages 10133 (year
  2021)NoStop
[Reich et al.(2005)Reich, Ferrari, Arenal, Loiseau, Bello, and Robertson]Reich2005May
  author author S. Reich, author A. C. Ferrari, author R. Arenal, author A. Loiseau, author I. Bello, and author J. Robertson, title title Resonant Raman scattering in cubic and hexagonal boron nitride, https://doi.org/10.1103/PhysRevB.71.205201 journal journal Phys. Rev. B volume 71, pages 205201 (year 2005)NoStop
[Stenger et al.(2017)Stenger, Schuéé, Boukhicha, Berini, Plaçais, Loiseau, and Barjon]Stenger2017Jun
  author author I. Stenger, author L. Schuéé, author M. Boukhicha, author B. Berini, author B. Plaçais, author A. Loiseau, and author J. Barjon, title title Low frequency Raman spectroscopy of few-atomic-layer thick hBN crystals, https://doi.org/10.1088/2053-1583/aa77d4 journal journal 2D Mater. volume 4, pages 031003 (year 2017)NoStop
[Banszerus et al.(2017)Banszerus, Janssen, Otto, Epping, Taniguchi, Watanabe, Beschoten, Neumaier, and Stampfer]Banszerus2017Feb
  author author L. Banszerus, author H. Janssen, author M. Otto, author A. Epping, author T. Taniguchi, author K. Watanabe, author B. Beschoten, author D. Neumaier, and author C. Stampfer, title title Identifying suitable substrates for high-quality graphene-based heterostructures, https://doi.org/10.1088/2053-1583/aa5b0f journal journal 2D Mater. volume 4, pages 025030 (year 2017)NoStop
[Caretti and Jiméénez(2012)]Caretti2012Sep
  author author I. Caretti and author I. Jiméénez, title title Influence of carbon content and nitrogen vacancies on the bonding structure and mechanical performance of graphite-like BCxN thin films, https://doi.org/10.1063/1.4752757 journal journal J. Appl. Phys. volume 112, pages 063525 (year 2012)NoStop
[Couto et al.(2014)Couto, Costanzo, Engels, Ki, Watanabe, Taniguchi, Stampfer, Guinea, and Morpurgo]Couto2014Oct
  author author N. J. G. Couto, author D. Costanzo, author S. Engels, author D.-K. Ki, author K. Watanabe, author T. Taniguchi, author C. Stampfer, author F. Guinea, and author A. F. Morpurgo, title title Random Strain Fluctuations as Dominant Disorder Source for High-Quality On-Substrate Graphene Devices, https://doi.org/10.1103/PhysRevX.4.041019 journal journal Phys. Rev. X volume 4, pages 041019 (year 2014)NoStop
[Lee et al.(2012)Lee, Ahn, Shim, Lee, and Ryu]Lee2012Aug
  author author J. E. Lee, author G. Ahn, author J. Shim, author Y. S. Lee, and author S. Ryu, title title Optical separation of mechanical strain from charge doping in graphene, https://doi.org/10.1038/ncomms2022 journal journal Nat. Commun. volume 3, pages 1 (year 2012)NoStop
[Neumann et al.(2015)Neumann, Reichardt, Venezuela, Dröögeler, Banszerus, Schmitz, Watanabe, Taniguchi, Mauri, Beschoten, Rotkin, and Stampfer]Neumann2015Sep
  author author C. Neumann, author S. Reichardt, author P. Venezuela, author M. Dröögeler, author L. Banszerus, author M. Schmitz, author K. Watanabe, author T. Taniguchi, author F. Mauri, author B. Beschoten, author S. V. Rotkin, and author C. Stampfer, title title Raman spectroscopy as probe of nanometre-scale strain variations in graphene, https://doi.org/10.1038/ncomms9429 journal
  journal Nat. Commun. volume 6, pages 8429 (year 2015)NoStop
[Vincent et al.(2018)Vincent, Panchal, Booth, Power, Jauho, Antonov, and Kazakova]Vincent2018Dec
  author author T. Vincent, author V. Panchal, author T. Booth, author S. R. Power, author A.-P. Jauho, author V. Antonov, and author O. Kazakova, title title Probing the nanoscale origin of strain and doping in graphene-hBN heterostructures, https://doi.org/10.1088/2053-1583/aaf1dc journal journal 2D Mater. volume 6, pages 015022 (year 2018)NoStop
[Solozhenko and Turkevich(1997)]Solozhenko1997Aug
  author author V. L. Solozhenko and author V. Z. Turkevich, title title High pressure phase equilibria in the Li3N-BN system: in situ studies, https://doi.org/10.1016/S0167-577X(97)00025-6 journal journal Mater. Lett. volume 32, pages 179 (year 1997)NoStop
[Maestre et al.(2021)Maestre, Toury, Steyer, Garnier, and Journet]Maestre2021Oct
  author author C. Maestre, author B. Toury, author P. Steyer, author V. Garnier, and author C. Journet, title title Hexagonal boron nitride: a review on selfstanding crystals synthesis towards 2D nanosheets, https://doi.org/10.1088/2515-7639/ac2b87 journal journal J. Phys.: Mater. volume 4, pages 044018 (year 2021)NoStop
[Sahni et al.(2018)Sahni, Ashuri, Emani, Kaduk, Néémeth, and Shaw]Sahni2018May
  author author K. Sahni, author M. Ashuri, author S. Emani, author J. A. Kaduk, author K. Néémeth, and author L. L. Shaw, title title On the synthesis of lithium boron nitride (Li_3BN_2), https://doi.org/10.1016/j.ceramint.2018.01.200 journal journal Ceram. Int. volume 44, pages 7734 (year 2018)NoStop
[Schmitt et al.(2023)Schmitt, Mele, Rosticher, Taniguchi, Watanabe, Maestre, Journet, Garnier, Fèève, Berroir, Voisin, Plaçais, and Baudin]Schmitt2023Apr
  author author A. Schmitt, author D. Mele, author M. Rosticher, author T. Taniguchi, author K. Watanabe, author C. Maestre, author C. Journet, author V. Garnier, author G. Fèève, author J. M. Berroir, author C. Voisin, author B. Plaçais, and author E. Baudin, title title High-field 1/f noise in hBN-encapsulated graphene transistors,  https://doi.org/10.1103/PhysRevB.107.L161104 journal journal Phys. Rev. B volume 107, pages L161104 (year 2023)NoStop
[Verguts et al.(2017)Verguts, Schouteden, Wu, Peters, Vrancken, Wu, Li, Erkens, Porret, Huyghebaert, Van Haesendonck, De Gendt, and Brems]Verguts2017Oct
  author author K. Verguts, author K. Schouteden, author C.-H. Wu, author L. Peters, author N. Vrancken, author X. Wu, author Z. Li, author M. Erkens, author C. Porret, author C. Huyghebaert, author C. Van Haesendonck, author S. De Gendt, and author S. Brems, title title Controlling Water Intercalation Is Key to a Direct Graphene Transfer, https://doi.org/10.1021/acsami.7b12573 journal journal ACS Appl. Mater. Interfaces volume 9, pages 37484 (year 2017)NoStop
[Hemmi et al.(2014)Hemmi, Bernard, Cun, Roth, Klööckner, Käälin, Weinl, Gsell, Schreck, Osterwalder, and Greber]Hemmi2014Mar
  author author A. Hemmi, author C. Bernard, author H. Cun, author S. Roth, author M. Klööckner, author T. Käälin, author M. Weinl, author S. Gsell, author M. Schreck, author J. Osterwalder, and author T. Greber, title title High quality single atomic layer deposition of hexagonal boron nitride on single crystalline Rh(111) four-inch wafers, https://doi.org/10.1063/1.4866648 journal journal
  Rev. Sci. Instrum. volume 85, pages 035101 (year 2014)NoStop
[Hemmi et al.(2021)Hemmi, Cun, Brems, Huyghebaert, and Greber]Hemmi2021Aug
  author author A. Hemmi, author H. Cun, author S. Brems, author C. Huyghebaert, and author T. Greber, title title Wafer-scale, epitaxial growth of single layer hexagonal boron nitride on Pt(111), https://doi.org/10.1088/2515-7639/ac0d9e journal journal J. Phys.: Mater. volume 4, pages 044012 (year 2021)NoStop
[Cun et al.(2018)Cun, Hemmi, Miniussi, Bernard, Probst, Liu, Alexander, Kleibert, Mette, Weinl, Schreck, Osterwalder, Radenovic, and Greber]Cun2018Feb
  author author H. Cun, author A. Hemmi, author E. Miniussi, author C. Bernard, author B. Probst, author K. Liu, author D. T. L. Alexander, author A. Kleibert, author G. Mette, author M. Weinl, author M. Schreck, author J. Osterwalder, author A. Radenovic, and author T. Greber, title title Centimeter-Sized Single-Orientation Monolayer Hexagonal Boron Nitride
  With or Without Nanovoids, https://doi.org/10.1021/acs.nanolett.7b04752 journal journal Nano Lett. volume 18, pages 1205 (year 2018)NoStop
[Jiméénez et al.(1997)Jiméénez, Jankowski, Terminello, Sutherland, Carlisle, Doll, Tong, Shuh, and Himpsel]Jimenez1997May
  author author I. Jiméénez, author A. F. Jankowski, author L. J. Terminello, author D. G. J. Sutherland, author J. A. Carlisle, author G. L. Doll, author W. M. Tong, author D. K. Shuh, and author F. J. Himpsel, title title Core-level photoabsorption study of defects and metastable bonding configurations in boron nitride, https://doi.org/10.1103/PhysRevB.55.12025 journal journal Phys. Rev. B volume 55, pages 12025 (year 1997)NoStop
[Caretti and Jiméénez(2011b)]Caretti2011Jul
  author author I. Caretti and author I. Jiméénez, title title Point defects in hexagonal BN, BC_3 and BC_xN compounds studied by x-ray absorption near-edge structure, journal journal J. Appl. Phys. volume 110, https://doi.org/10.1063/1.3602996 10.1063/1.3602996 (year 2011b)NoStop
[Roux et al.(2024)Roux, Arnold, Carréé, Janzen, Edgar, Maestre, Toury, Journet, Garnier, Steyer, Taniguchi, Watanabe, Loiseau, and Barjon]Roux2024Apr
  author author S. Roux, author C. Arnold, author E. Carréé, author E. Janzen, author J. H. Edgar, author C. Maestre, author B. Toury, author C. Journet, author V. Garnier, author P. Steyer, author T. Taniguchi, author K. Watanabe, author A. Loiseau, and author J. Barjon, title title Surface recombination and out-of-plane
  diffusivity of free excitons in hexagonal boron nitride, https://doi.org/10.1103/PhysRevB.109.155305 journal journal Phys. Rev. B volume 109, pages 155305 (year 2024)NoStop
[Plaud et al.(2019)Plaud, Schuéé, Watanabe, Taniguchi, Fossard, Ducastelle, Loiseau, and Barjon]Plaud2019Jun
  author author A. Plaud, author L. Schuéé, author K. Watanabe, author T. Taniguchi, author F. Fossard, author F. Ducastelle, author A. Loiseau, and author J. Barjon, title title Exciton-exciton annihilation in hBN, https://doi.org/10.1063/1.5090218 journal journal Appl. Phys. Lett. volume 114, pages 232103 (year 2019)NoStop
[Geick et al.(1966)Geick, Perry, and Rupprecht]Geick1966Jun
  author author R. Geick, author C. H. Perry, and author G. Rupprecht, title title Normal Modes in Hexagonal Boron Nitride, https://doi.org/10.1103/PhysRev.146.543 journal journal Phys. Rev. volume 146, pages 543 (year 1966)NoStop
[Cuscóó et al.(2020)Cuscóó, Edgar, Liu, Li, and Artúús]Cusco2020Apr
  author author R. Cuscóó, author J. H. Edgar, author S. Liu, author J. Li, and author L. Artúús, title title Isotopic Disorder: The Prevailing Mechanism in Limiting the Phonon Lifetime in Hexagonal BN, https://doi.org/10.1103/PhysRevLett.124.167402 journal journal Phys. Rev. Lett. volume 124, pages 167402 (year 2020)NoStop
[Gorbachev et al.(2011)Gorbachev, Riaz, Nair, Jalil, Britnell, Belle, Hill, Novoselov, Watanabe, Taniguchi, Geim, and Blake]Gorbachev2011Feb
  author author R. V. Gorbachev, author I. Riaz, author R. R. Nair, author R. Jalil, author L. Britnell, author B. D. Belle, author E. W. Hill, author K. S. Novoselov, author K. Watanabe, author T. Taniguchi, author A. K. Geim, and author P. Blake, title title Hunting for Monolayer Boron Nitride: Optical and Raman Signatures, https://doi.org/10.1002/smll.201001628 journal journal Small volume 7, pages 465 (year 2011)NoStop
[Uslu et al.(2024)Uslu, Ouaj, Tebbe, Nekrasov, Bertram, Schüütte, Watanabe, Taniguchi, Beschoten, Waldecker, and Stampfer]Uslu2024Feb
  author author J.-L. Uslu, author T. Ouaj, author D. Tebbe, author A. Nekrasov, author J. H. Bertram, author M. Schüütte, author K. Watanabe, author T. Taniguchi, author B. Beschoten, author L. Waldecker, and author C. Stampfer, title title An open-source robust machine learning platform for real-time detection and classification of 2D material flakes, https://doi.org/10.1088/2632-2153/ad2287 journal journal Mach.
  Learn.: Sci. Technol. volume 5, pages 015027 (year 2024)NoStop
[Nemanich et al.(1981)Nemanich, Solin, and Martin]Nemanich1981Jun
  author author R. J. Nemanich, author S. A. Solin, and author R. M. Martin, title title Light scattering study of boron nitride microcrystals, https://doi.org/10.1103/PhysRevB.23.6348 journal journal Phys. Rev. B volume 23, pages 6348 (year 1981)NoStop
[Song et al.(2010)Song, Ci, Lu, Sorokin, Jin, Ni, Kvashnin, Kvashnin, Lou, Yakobson, and Ajayan]Song2010Aug
  author author L. Song, author L. Ci, author H. Lu, author P. B. Sorokin, author C. Jin, author J. Ni, author A. G. Kvashnin, author D. G. Kvashnin, author J. Lou, author B. I. Yakobson, and author P. M. Ajayan, title title Large Scale Growth and Characterization of Atomic Hexagonal Boron Nitride Layers, https://doi.org/10.1021/nl1022139 journal journal Nano Lett. volume 10, pages 3209 (year
  2010)NoStop
[Shi et al.(2010)Shi, Hamsen, Jia, Kim, Reina, Hofmann, Hsu, Zhang, Li, Juang, Dresselhaus, Li, and Kong]Shi2010Oct
  author author Y. Shi, author C. Hamsen, author X. Jia, author K. K. Kim, author A. Reina, author M. Hofmann, author A. L. Hsu, author K. Zhang, author H. Li, author Z.-Y. Juang, author Mildred. S. Dresselhaus, author L.-J. Li, and author J. Kong, title title Synthesis of Few-Layer Hexagonal Boron Nitride Thin Film by Chemical Vapor Deposition, https://doi.org/10.1021/nl1023707
  journal journal Nano Lett. volume 10, pages 4134 (year 2010)NoStop
[Hadid et al.(2022)Hadid, Colambo, Avila, Plaud, Boyaval, Deresmes, Nuns, Dudin, Loiseau, Barjon, Wallart, and Vignaud]Hadid2022Nov
  author author J. Hadid, author I. Colambo, author J. Avila, author A. Plaud, author C. Boyaval, author D. Deresmes, author N. Nuns, author P. Dudin, author A. Loiseau, author J. Barjon, author X. Wallart, and author D. Vignaud, title title Molecular beam epitaxial growth of multilayer 2D-boron nitride on Ni substrates from borazine and plasma-activated nitrogen, https://doi.org/10.1088/1361-6528/ac99e5 journal journal Nanotechnology volume 34, pages 035601 (year 2022)NoStop
[Bisswanger et al.(2022)Bisswanger, Winter, Schmidt, Volmer, Watanabe, Taniguchi, Stampfer, and Beschoten]Bisswanger2022Jun
  author author T. Bisswanger, author Z. Winter, author A. Schmidt, author F. Volmer, author K. Watanabe, author T. Taniguchi, author C. Stampfer, and author B. Beschoten, title title CVD Bilayer Graphene Spin Valves with 26 μm Spin Diffusion Length at Room Temperature, https://doi.org/10.1021/acs.nanolett.2c01119 journal journal Nano Lett. volume 22, pages 4949 (year 2022)NoStop
[Páálinkáás et al.(2022)Páálinkáás, Káálvin, Vancsóó, Kandrai, Szendrő, Néémeth, Néémeth, Pekker, Pap, Petrik, Kamaráás, Tapasztóó, and Nemes-Incze]Palinkas2022Nov
  author author A. Páálinkáás, author G. Káálvin, author P. Vancsóó, author K. Kandrai, author M. Szendrő, author G. Néémeth, author M. Néémeth, author ÁÁ. Pekker, author J. S. Pap, author P. Petrik, author K. Kamaráás, author
  L. Tapasztóó, and author P. Nemes-Incze, title title The composition and structure of the ubiquitous hydrocarbon contamination on van der Waals materials, https://doi.org/10.1038/s41467-022-34641-7 journal journal Nat. Commun. volume 13, pages 1 (year 2022)NoStop
[Ferrari et al.(2006)Ferrari, Meyer, Scardaci, Casiraghi, Lazzeri, Mauri, Piscanec, Jiang, Novoselov, Roth, and Geim]Ferrari2006Oct
  author author A. C. Ferrari, author J. C. Meyer, author V. Scardaci, author C. Casiraghi, author M. Lazzeri, author F. Mauri, author S. Piscanec, author D. Jiang, author K. S. Novoselov, author S. Roth, and author A. K. Geim, title title Raman Spectrum of Graphene and Graphene Layers, https://doi.org/10.1103/PhysRevLett.97.187401 journal journal Phys. Rev. Lett. volume 97, pages 187401 (year
  2006)NoStop
[Graf et al.(2007)Graf, Molitor, Ensslin, Stampfer, Jungen, Hierold, and Wirtz]Graf2007Feb
  author author D. Graf, author F. Molitor, author K. Ensslin, author C. Stampfer, author A. Jungen, author C. Hierold, and author L. Wirtz, title title Spatially Resolved Raman Spectroscopy of Single- and Few-Layer Graphene, https://doi.org/10.1021/nl061702a journal journal Nano Lett. volume 7, pages 238 (year 2007)NoStop
[Ferrari and Basko(2013)]Ferrari2013Apr
  author author A. C. Ferrari and author D. M. Basko, title title Raman spectroscopy as a versatile tool for studying the properties of graphene, https://doi.org/10.1038/nnano.2013.46 journal journal Nat. Nanotechnol. volume 8, pages 235 (year 2013)NoStop
[Forster et al.(2013)Forster, Molina-Sanchez, Engels, Epping, Watanabe, Taniguchi, Wirtz, and Stampfer]Forster2013Aug
  author author F. Forster, author A. Molina-Sanchez, author S. Engels, author A. Epping, author K. Watanabe, author T. Taniguchi, author L. Wirtz, and author C. Stampfer, title title Dielectric screening of the Kohn anomaly of graphene on hexagonal boron nitride, https://doi.org/10.1103/PhysRevB.88.085419 journal journal Phys. Rev. B volume 88, pages 085419 (year 2013)NoStop
[Sonntag et al.(2023)Sonntag, Watanabe, Taniguchi, Beschoten, and Stampfer]Sonntag2023Feb
  author author J. Sonntag, author K. Watanabe, author T. Taniguchi, author B. Beschoten, and author C. Stampfer, title title Charge carrier density dependent Raman spectra of graphene encapsulated in hexagonal boron nitride, https://doi.org/10.1103/PhysRevB.107.075420 journal journal Phys. Rev. B volume 107, pages 075420 (year 2023)NoStop
[Lin et al.(2012)Lin, Lu, Yeh, Jin, Suenaga, and Chiu]Lin2012Jan
  author author Y.-C. Lin, author C.-C. Lu, author C.-H. Yeh, author C. Jin, author K. Suenaga, and author P.-W. Chiu, title title Graphene Annealing: How Clean Can It Be?, https://doi.org/10.1021/nl203733r journal journal Nano Lett. volume 12, pages 414 (year 2012)NoStop
[Schwartz et al.(2019)Schwartz, Chuang, Rosenberger, Sivaram, McCreary, Jonker, and Centrone]Schwartz2019Jul
  author author J. Schwartz, author H.-J. Chuang, author M. R. Rosenberger, author S. V. Sivaram, author K. M. McCreary, author B. T. Jonker, and author A. Centrone, title title Chemical Identification of Interlayer Contaminants within van der Waals Heterostructures, https://doi.org/10.1021/acsami.9b06594 journal journal ACS Appl. Mater. Interfaces volume 11, pages 25578 (year 2019)NoStop
[Volmer et al.(2021)Volmer, Seidler, Bisswanger, Tu, Schreiber, Stampfer, and Beschoten]Volmer2021Mar
  author author F. Volmer, author I. Seidler, author T. Bisswanger, author J.-S. Tu, author L. R. Schreiber, author C. Stampfer, and author B. Beschoten, title title How to solve problems in micro- and nanofabrication caused by the emission of electrons and charged metal atoms during e-beam evaporation, https://doi.org/10.1088/1361-6463/abe89b journal journal J. Phys. D: Appl. Phys. volume 54, pages 225304 (year 2021)NoStop
[ICE(2021)]ICE
  @noop  title  IEC TS 62607-6-6:2021(E) Nanomanufacturing - Key control characteristics - Part 6-6: “Graphene - Uniformity of strain in graphene analyzed by Raman spectroscopy (year 2021)NoStop





