OPTICAL ANISOTROPY OF (113)-ORIENTED GAAS ALAS SUPERLATTICES/

The optical properties of (113)-oriented GaAs/AlAs superlattices grown by atomic-layer molecular-beam epitaxy at low substrate temperature h ave been studied by means of piezoreflectance techniques. Several tran sitions have been detected which exhibit heavy-hole and light-hole cha racter. The heavy-hole transitions are more polarized along the [332BA R] direction whereas the light-hole transitions are more polarized alo ng the [110BAR] direction. We have also performed calculations for the se superlattices by using an empirical tight-binding Hamiltonian. Acco rding to the results thus obtained the observed optical anisotropy is related to the different components of the valence-band wave functions of the superlattices.