Enhancement in Optical Transition in (111)-Oriented GaAs-AlGaAs Quantum Well Structures

The enhancement of the optical transition rate in (111)-oriented GaAs-AlGaAs quantum wells (QW's) compared with (100) QW's has been confirmed by photoluminescence. It is experimentally determined by absorption measurements of QW's that the anisotropy of the heavy-hole band in GaAs is extremely large; $\frac{m_{\mathrm{hh}}^{*}\mathrm{}\left[111\right]\mathrm{}}{m_{\mathrm{hh}}^{*}\mathrm{}\left[100\right]\mathrm{}}=2.65\mathrm{}$. This large anisotropy in the host GaAs is considered to result in the higher optical transition rate in (111) QW's compared with (100) QW's.