Ab-initio calculation of the As and Se L3,2-edge XANES of As2Se3 and Zn-doped As2Se3 and comparison to the experiments

Abstract

We present a theoretical interpretation of the L3,2-edge XANES (X-ray Absorption Near Edge Structure) spectra of un-doped and zinc-doped As2Se3 glasses. L3,2-edge XANES of glasses with compositions, (As2Se3)100−x(Zn)x (x=3, 5, 7, 10) and (As2Se3)100−y (ZnSe)y (y=5, 20), have also been obtained experimentally. The experimental L3,2-edge spectra of As and Se are compared to the theoretically calculated spectra by two ab-initio methods: the self-consistent methods of DFT (Density Functional Theory) and RSMS (Real Space Multiple Scattering). The effect of morphology (powder vs. thin film) and the addition of Zn are also demonstrated by valence band obtained from XPS (X-ray Photoelectron Spectroscopy) spectra. The effects of the cluster size and the doping of Zn into the As2Se3 have also been simulated for the L3,2-edge XANES.