Anisotropy in the interband transitions of (110) oriented quantum wells

The reduced symmetry of the quantum confinement direction which is inherent to quantum wells grown on (110) oriented substrates results in in-plane polarization anisotropy of the optical transitions. We present a study of this anisotropy using photoluminescence excitation spectroscopy of (110) and (100) oriented quantum well structures. The spectral features observed in the photoluminescence-excitation spectra of these structures are modeled using an eight band k p-type effective mass theory. We directly determine the valence band anisotropy of the quantum well material from the orientational dependence of the transition energies and oscillator strengths. We found (γ3 - γ2)/(γ3 + γ2) = 0.18 ± 0.03, where γ2.3 are the GaAs Luttinger parameters.