ENERGY-SPECTRUM AND SIZE QUANTIZATION IN PARTIALLY ORDERED SEMICONDUCTOR ALLOYS

We present the analytical theory for the conduction-band spectrum in partially ordered semiconductor alloys. It is assumed that the ordering causes the coupling of the electronic states of Gamma minimum with the states of the closest-in-energy L minimum only. We analyze the reduction of the band gap, change of the effective mass, nonparabolicity, and anisotropy of the electronic spectrum, caused by ordering. Using the spectrum obtained we study the size quantization in an ordered domain sandwiched between two disordered regions. We also calculate the electronic spectrum in the region of interpenetration of two variants of ordering along the [($) over bar 111] and [1 $($) over bar$$ 11] directions. The localization of an electron in such a region is studied.