In order to clarify the electronic and optical properties of wide-energy ga
p zinc-blende structures ZnSe, MgSe and their alloys (ZnSe)(1-x)(MgSe)(x),
a simple pseudo-potential scheme (EPM) within an effective potential, the v
irtual crystal approximation (VCA) which incorporates compositional disorde
r as an effective potential, is presented. Various quantities, including th
e fundamental band gap, the energies of several optical gaps, charge densit
ies, ionicity character, transverse effective charge, and refractive index
are obtained for this alloy. (C) 2001 Academic Press.