Finite‐cluster approximation for deep‐level impurities in silicon carbide

Abstract

AbstractA series of 12 silicon carbide finite clusters has been investigated to determine a possible model for transition‐metal deep‐level impurities in several Si sites of the material. All electronic structure calculations were done using the extended Hückel method. By taking account of boundary condition effects upon the electronic structure of the pure and V‐substitutional systems, it was found that the cluster series could be classified into two groups: a large‐gap and a small‐gap group. The small‐gap group arises from spurious border Si‐3p levels that appear inside the forbidden gap. It was consequently suggested that large‐gap clusters are more suitable for describing the impurity. It is also suggested that possibly new V, Si, and C parameters could lead to both a good description of the pure and doped material. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 88–96, 2003