Anisotropic Optical Transitions in Semiconductor Quantum Wells

Calculations have been made of the in-plane behavior of optical transition matrix elements at the band edge for quantum well films of several crystallograhic directions. This calculation takes into account the multiplicity of the valence band including the split-off band. The (001) film shows in-plane isotropy, while the (110) and (311) films reveal marked and slight anisotropy, respectively. The (111) film exhibits isotropic behavior despite the fact that each state of the doubly degenerate subband in the valence band produces an extremely anisotropic optical transition.