X-ray photoelectron spectroscopy studies of thin Ge xSb 40− xS 60 chalcogenide films

Abstract

Thin Ge x Sb 40− x S 60 ( x=5, 15, 20, 25 and 27) chalcogenide films have been investigated by X-ray photoelectron spectroscopy (XPS). X-ray photoelectron spectra show that there is a peculiarity in the relative intensity ratio of the Sb 4d photoelectron peak associated with Sb 2S 3 to the Sb 4d photoelectron peak associated Sb 2S 5 at an average co-ordination number Z of 2.65–2.67. After contamination and photo-oxidation layers were removed from the surface of the films, X-ray photoelectron spectra were measured again. It has been found that binding energies of the Ge 2p and Sb 3d 3/2 photoelectron peaks, which reflect the electronic structure at lower core energy levels, are independent of Z. However, the binding energies of the Ge 3d and Sb 4d photoelectron peaks are more sensitive to Z and have a discontinuity at Z=2.65.