X-ray Photoelectron Spectroscopy of Sb₂S₃Crystals

Abstract

The paper presents the X-ray photoelectron spectra (XPS) of the valence band and core levels of semiconductor ferroelectric Sb2S3 single crystals, which show weak phase transitions and anomalies of various physical properties. The XPS were measured with monochromatized Al K α radiation in the energy range 0-1450 eV and the temperature range 160-450 K. The valence band is located 0.8-7.5 eV below the Fermi level. Experimental results of the valence band and core levels are compared with the results of theoretical ab initio calculations of the molecular model of Sb2S3 crystal. The chemical shifts in Sb2S3 crystal for the Sb and S states are obtained. Results revealed that the small structural rearrangements at the phase transition T c1 = 300 K shift the Fermi level and all electronic spectrum. Also, temperature dependence of a spontaneous polarisation shifts the electronic spectra of the valence band and core levels. Specific temperature-dependent excitations in Sb 3d core levels are also revealed.