In-doped As2Se3 thin films studied by Raman and X-ray photoelectron spectroscopies

Abstract

Amorphous In-doped As2Se3 films with nominal indium contents x up to 7 at.% were prepared by thermal evaporation. Atomic force microscopy studies confirm the uniform film structure with a surface roughness near 5 nm, noticeably higher than for similarly prepared undoped As2Se3 film. X-ray photoelectron spectroscopy (XPS) studies enabled the chemical composition of the films to be examined. As follows from the XPS data, the In content in the film strongly decreases with the film depth. For films with x ≥ 2 at.%, Raman features attributed to transverse and longitudinal optical phonons of InAs are revealed in the Raman spectra as an evidence for the formation of InAs nanocrystallites in the As2Se3:In film under laser illumination.