Effects of disorder on the optical gap of (Zn,Mg)(S,Se)

摘要: The electronic properties and optical gap of (Zn,Mg)(S,Se) wide-gap solid solutions are studied using ab initio techniques starting from the previously determined atomistic structure alloy. Compositional disorder is shown to close substantially with respect predictions virtual-crystal approximation. bowing fundamental versus composition predicted by our calculations in very good agreement experiments available for Zn(S,Se) pseudobinary At temperatures typical molecular-beam epitaxy growth, quaternary alloy displays a rather large amount short-range order whose effect slightly but unmistakably open gap. Our results agree well recent experimental data