Composition-dependent band gap in ZnSxSe1-x : a combined experimental and theoretical study

• Published in: Solid state sciences 2006, Vol.8 (1), p.44-49
• Main Authors: HOMANN, Thorsten, HOTJE, Urte, BINNEWIES, Michael, BÖRGER, Alexander, BECKER, Klaus-Dieter, BREDOW, Thomas
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Density functional theory, local density approximation; Electron density of states and band structure of crystalline solids; Electron states; Exact sciences and technology; Physics; Semiconductor compounds; Theories and models of many electron systems
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2005.08.015

The energetic, structural and electronic properties of ZnSZnSe mixed phases have been investigated by a combined experimental and theoretical approach. The crystallographic parameters of the mixed crystals have been measured by X-ray powder methods. The band gaps are determined from optical spectroscopy. The results of quantum chemical calculations at density functional level are compared to the experimental data. The solid solutions were modeled with supercells of varying S and Se content. Both experimentally and theoretically, an almost linear dependence of the lattice constant and cohesion energy on composition was found. The influence of anion distribution and local relaxation on the calculated electronic structure was investigated. The optical band gap shows a non-linear dependence on the S content.