Anda di halaman 1dari 5




Prof E Magner (Dean S&E)
Prof S Hampshire (Emeritus)
Prof U Bangert (Dept. of Physics)
Dr C Silien (Dept. of Physics)
Dr S Belochapkine (MSSI)
Dr F Laffir (MSSI)
Dr L Kalais (MSSI)
Dr W Redington (MSSI)
Dr Y Guo (MSSI)

MODULE CODE AND TITLE: MT6011 Advanced Characterisation

of Materials 1 GRADING SCHEME

TERM: Autumn 2016/2017 50% Marks for Exam

50% Marks for coursework

TIME: 2.5 Hrs

Answer FIVE (5) questions.

1. a) Briefly explain the basis of Raman spectroscopy. Draw a schematic

diagram of a Raman spectrometer. 7

b) Calculate the difference in energy (in units of cm-1) of two energy states
A and B at 25 oC that produces a population ratio of 1:10. 3

c) At what wavelengths (in cm-1) would the Stokes and anti-Stokes Raman
lines for carbon tetrachloride (Δv = 218, 314, 459, 762, and 790 cm−l)
appear, if the source used were:
i) a helium-neon laser (632.8 nm)
ii) an argon-ion laser (488.0 nm) 3

Q1. continued…..

MODULE CODE & TITLE: MT6011 Advanced Characterisation of Materials 1


Q1. continued…..

d) The hydrogen halides have the following fundamental vibrational

frequencies: HF (4141.3 cm-1), H35Cl (2998.9 cm-1), H81Br (2649.7 cm-
), H127I (2309.5 cm-1). Provide an explanation for the observed changes
in frequency. Calculate the force constant of the hydrogen chloride
bond. The mass of a hydrogen atom is 1 Dalton (1.67 x 10-24 g). 4

e) How many vibrational modes are possible for: CH4, Na+Cl-, C2H6, and
DCl. 3

2. a) Briefly describe the photoelectric effect with an aid of an equation in

relation to X-ray Photoelectron Spectroscopy (XPS). 3

b) Give approximate analysis depths probed by XPS and AES (Auger

Electron Spectroscopy) techniques? 2

c) What type of samples require charge compensation during XPS

measurements and why? 3

d) State the two methods of depth profiling. 2

e) Samples X and Y are composed of Ni nanoparticles which have

undergone surface oxidation and differ only in particle size. High
resolution spectra of Ni 2p3/2 (shown below) were measured to
determine the chemical states of nickel.

Sample X Sample Y B
Ni 2p3/2 Ni 2p3/2
Intensity (a.u.)
Intensity (a.u.)


866 862 858 854 850 866 862 858 854 850
Binding energy (eV) Binding energy (eV)

Q2. e) continued….

MODULE CODE & TITLE: MT6011 Advanced Characterisation of Materials 1


Q2. e) continued….

i) Identify peaks labelled A and B (using the table below) and the
broad feature labelled C. 6

ii) One sample is composed of particles of 2 nm and the other 8 nm

diameter. Match particle sizes with samples X and Y, stating
reasons. 4

Ni 2p3/2 Binding Energy (eV)

Compound 852 853 854 855 856 857


3. a) Give three (3) examples of scanning probe microscopy (SPM) and for
each indicate which physical phenomenon is measured. 6

b) The spatial resolution in scanning probe microscopy (SPM) is

determined by two factors. Cite these 2 factors and explain how they
relate to the spatial resolution. 8

c) Justify why scanning tunnelling microscopy (STM) images of

molecules primarily reveal the symmetry of their electronic orbitals of
energies close to the Fermi level. 6

4. a) Describe the main functional parts of a Mass Spectrometer. 10

b) Explain the principles of Time of Flight Mass Analysis. 10


MODULE CODE & TITLE: MT6011 Advanced Characterisation of Materials 1


5. a) State the three types of image contrast obtained in a Transmission

Electron Microscope, and explain briefly, how they arise. 6

b) Explain what is meant by the term ‘2-beam’ condition and its

significance for the analysis of dislocations. Thereby explain what is
meant by the ‘invisibility criterion’. 6

c) Shown below is an HREM image of diamond. Give a brief account of

the information that can be extracted. (In your explanation you should
include e.g. the contrast mechanism, the scale of features and what the
smallest feature represents). Comment on the structural perfection of
the particle. 6

d) Briefly explain the basis of electron energy loss spectroscopy and what
it is applied to. 6

MODULE CODE & TITLE: MT6011 Advanced Characterisation of Materials 1


6. a) State Bragg’s Law.

State the relationship between interplanar spacing, the size of the unit
cell and the Miller indices for a cubic crystal.
By combining this with Bragg’s law, index the pattern for cubic
BaTiO3, the first 5 reflections for which are found at the following
values of 2(o) using CuK X-radiation with  = 1.5406 Å:

1 22.0
2 31.4
3 38.6
4 45.0
5 50.6

Hence calculate the unit cell dimension a. 12

b) State the Weiss Zone Law and give the coordinates [uvw] of a zone axis
in terms of two planes in the same zone with indices (h1k1l1) and
(h2k2l2). Two planes (111) and (200) are observed to lie in the same
zone. Give the indices for the direction of the zone axis. 8

7. a) Explain how manipulation of accelerating voltage, beam current,

working distance and aperture size affect the resolution and quality of
images collected in a scanning electron microscope. 7

b) Explain why using a smaller beam size is one method to improve

images showing astigmatism. 3

c) Given your knowledge of the way in which the primary beam interacts
with specimens in a scanning electron microscope operating at an
accelerating voltage of 20kV, explain why the energy dispersive X-ray
analysis spectrum collected when the beam is perpendicular to a thin
gold layer (50 nm thick) covering a 5 µm thick Ni layer on an electronic
connector shows only the presence of Nickel. The use of diagrams to
illustrate your answer is encouraged. 7

d) How might you expect specimen tilting to affect the observed X-ray
outcome? 3