EXCITONS IN (311) ORIENTED SUPERLATTICES - OPTICAL ANISOTROPIES

The optical response of excitons in (311) oriented GaAs/AlAs superlatt ices grown by atomic layer molecular beam epitaxy at low substrate tem perature is studied by piezoreflectance. Several transitions are detec ted showing heavy hole and light hole character. The heavy hole transi tions are more polarized along the [233BAR] direction whereas the ligh t hole ones are more polarized along the [011BAR] direction.According to the calculation based on an empirical tight binding model, the obse rved optical anisotropy is related to the different components of the superlatices valence band wave functions.