Isostructural BaSi₂, BaGe₂ and SrGe₂: electronic and optical properties

Abstract We have performed a theoretical study of the electronic band structure, density of states, dielectric function and absorption coefficient of isostructural BaSi 2 , BaGe 2 and SrGe 2 compounds by means of different ab initio methods. All materials are found to be indirect band‐gap semiconductors displaying almost equal dispersion of bands close to the gap region. The energy gaps of 0.83, 0.57 and 0.44 eV are estimated for BaSi 2 , BaGe 2 and SrGe 2 , respectively. Analysis of the absorption coefficient of BaSi 2 in comparison with data for other semiconducting silicides indicates its prospects for a solar cell application. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)