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 have been studied by means of piezoreflectance techniques. Several transitions have been detected which exhibit heavy-hole and light-hole character. The heavy-hole transitions are more polarized along the [332BAR] direction whereas the light-hole transitions are more polarized along the [110BAR] direction. We have also performed calculations for these superlattices by using an empirical tight-binding Hamiltonian. According to the results thus obtained the observed optical anisotropy is related to the different components of the valence-band wave functions of the superlattices.