The controlled placement of colloidal semiconductor nanocrystals
(NCs) onto planar surfaces is crucial for scalable fabrication of
single-photon emitters on-chip, which are critical elements of optical
quantum computing, communication, and encryption. The positioning
of colloidal semiconductor NCs such as metal chalcogenides or perovskites
is still challenging, as it requires a nonaggressive fabrication process
to preserve the optical properties of the NCs. In this work, periodic
arrays of 2500 nanoholes are patterned by electron beam lithography
in a poly(methyl methacrylate) (PMMA) thin film on indium tin oxide/glass
substrates. Colloidal core/shell CdSe/CdS NCs, functionalized with
a SiO2capping layer to increase their size and facilitate
deposition into 100 nm holes, are trapped with a close to optimal
Poisson distribution into the PMMA nanoholes via a capillary assembly
method. The resulting arrays of NCs contain hundreds of single-photon
emitters each. We believe this work paves the way to an affordable,
fast, and practical method for the fabrication of nanodevices, such
as single-photon-emitting light-emitting diodes based on colloidal
semiconductor NCs.