Effective Mass Reversal on InxAl1-xAs/GaAs Strained-Layer Superlattices

Here, we report on the first evaluation of two-dimensional hole masses of GaAs layers in In x Al1-x As/GaAs strained-layer superlattices. The mass change in the valence band of the GaAs layers under a biaxial-layer strain has been determined by comparing the photoluminescence line shape with a theoretical calculation of the spectral dependence of the spontaneous emission rate. Reversals of the effective hole masses parallel to the heterointerfaces are important for evaluating optical transitions in strained-layer superlattices.