On the Band Structure of Ultrathin Layer Semiconductor Superlattices

Abstract

AbstractA band structure calculation of (GaAs)m(AlAs)m superlattices with m = 1, 2, 3, 4 is made by the recursion method in the Bloch sum basis. A dependence of the direct band gap width E on thickness m of the alternating layers is obtained which agrees well with other calculations and experimental photoluminescence data. The scheme of determination of the sp3s* Hamiltonian parameters proposed earlier is modified which affects significantly the results for the band discontinuities at the GaAs/AlAs heterojunction and for the “local” band gap width Eg of superlattices obtained from an analysis of the local density of electron states averaged over the layers parallel to the interface. A comparison of the lattice‐averaged band gap width E with the local width Eg shows that the latter yield an underestimated value for the gap width.