Band structure engineering for maximal light-hole behaviour in strained quantum well systems

Abstract

Abstract We show that the highest valence subband can be light-hole-like over a significant energy range (50–100 meV) in the plane of a strained layer superlattice where (i) the light hole and heavy hole confinement wells are in different regions of the superlattice and (ii) the heavy hole confinement well is deeper than the light hole confinement well. The separate confinement minimises the interaction between light hole and heavy hole zone centre states, thus reducing subband non-parabolicity due to state mixing, while the different well depths enhances the splitting between the highest heavy hole and light hole states. (InAlGa)As-(GaAl)As sould be an ideal material system to demonstrate maximal light-hole behaviour, behaviour of significant benefit for high hole mobility and optoelectronic applications.