Electronic structure and optical properties of ternary CdXP2 semiconductors (X = Si, Ge and Sn) under pressure

摘要

We investigated the pressure dependence of the excitation energies of the ternary CdXP2 (with X = Si, Ge and Sn) pnictide semiconductors in the chalcopyrite structure. Using a new full potential augmented plane wave plus local orbitals method, we have studied the effect of high pressure on the band structure and on the optical properties. We show that the pseudodirect band gap of CdSiP2 narrows with increasing pressure and the direct band gap of CdGeP2 changes to a pseudo-direct band gap. Furthermore, we find that the magnitude of the pressure coefficients for this series of materials changes from the pseudodirect to a direct band gap. (C) 2003 Elsevier B.V. All rights reserved.