Enhancement of Quantum-Confined Stark Effect in GaAs-AlGaAs Quantum Wells by Quantization along the [111] Axis

Photoluminescence measurements have been performed in (100)- and (111)-oriented GaAs-AlGaAs quantum well structures (QWS) subject to an electric field perpendicular to the well plane. In the (111) QWS, the energy shift of the heavy hole exciton induced by an electric field was found to be larger than that in the (100) QWS having the same well width. This difference of electric field dependence between (100) and (111) QWS is well explained by theoretical calculations that consider the anisotropy of the heavy hole mass. Emission due to a “forbidden” transition has been also observed in the (111) QWS.