ENERGY-BAND STRUCTURE CALCULATION OF GEXSN1-X AND SIXSN1-X ALLOYS

Starting from band structures of the constituent materials, the electr onic band structure of the semiconducting alloys GexSn1-x and SixSn1-x are calculated by the empirical pseudopotential method using a correc ted virtual crystal approximation (VCA) which incorporates composition al disorder as an effective potential. Various quantities, including t he bowing parameter of the fundamental band gap, the energies of sever al optical gaps, and the crossover of the band gaps are predicted.