Ternary CdS 1– x Se x nanocrystals formed in Cd‐doped As–Se–S films due to photoenhanced diffusion during micro‐Raman measurement

Micro‐Raman spectra of amorphous As–Se–S:Cd films prepared by thermal evaporation on silicon and silicate glass substrates measured at different laser power densities show the formation of CdS 1– x Se x nanocrystals in the As–Se–S:Cd film under laser beam illumination due to a photoinduced material transfer and photoenhanced diffusion in the laser spot area. The material transfer and the photoenhanced diffusion are caused by a non‐thermal interaction of light with the amorphous As–Se–S:Cd films. The chemical composition of the CdS 1– x Se x nanocrystals can be determined from the difference of the CdSe‐like and CdS‐like LO phonon wavenumbers in the Raman spectra. The photoluminescence peak energies are in agreement with the CdS 1– x Se x composition, with the average nanocrystal size being somewhat above the exciton Bohr radius.