Local electronic structure of ZnS and ZnSe doped by Mn, Fe, Co, and Ni from x-ray-absorption near-edge structure studies

Abstract

Systematic studies of x-ray-absorption near-edge structure (XANES) at the K edge of cations and anions in ZnS, ZnSe, and ZnMS and ZnMSe compounds, with M being a transition metal (Mn, Fe, Co, Ni), were performed. Our investigations have shown, in agreement with earlier literature results of multiple-scattering theory, that the distribution of unoccupied p-like states around cation atoms is mainly determined by the type of anion and does not depend significantly on the M concentration. Three peak structures can be found in the cation K-edge XANES of the sulphides, whereas a two-peak structure is observed in selenides. The effective charge transfer for the M cation was estimated within 2--2.5e, from measured chemical shifts of the respective K edges. Additionally, direct evidence of hybridization between the states of M and p states of S was found from S K-edge XANES studies. The empirical correlation between the shape of M K edges and the solubility limit of M in the investigated solid matrices was revealed. \textcopyright{} 1996 The American Physical Society.