Electronic structure of (In,Ga) As(Ga, Al) As strained-layer quantum wells

Abstract

We discuss the growth of epitaxial structures of (In, Ga) As on GaAs substrates, with elastic and plastic strain, and study the effect of the corresponding built-in strain on the photoluminescence of quantum wells inserted into such buffer layers. In addition, we examine the effect of built-in strain on the full electronic structure of strained-layer quantum wells. Reflectivity data taken at 2 K, where we could measure ground state type I, as well as excited type I and type II transitions, have revealed that a correct description of these heterostructures requires including the effect of the spin-orbit split-off states in the valence band physics as soon as the configuration of the electron-to-light-hole potential profiles switches from type II to type I. We anticipate that this effect should be included for the calculation of threshold currents in quantum well lasers made from such heterostructures.