Light-heavy hole mixing and in-plane optical anisotropy of InP-AlxIn1-xAs type-II multiquantum wells

We report investigations of the giant in-plane polarization anisotropy of InP-AlxIn1-xAs type-II multiquantum wells. An absorption polarization rate up to 30% is observed over a very broad (> 100 meV) spectral range, in contrast with type-I quantum wells where similar effects are observed in a much narrower range. This property results from the heavy- and light-hole band mixing due to the interface symmetry reduction, combined with the lifting of parity selection rule due to carrier spatial separation in type-II quantum wells. Calculations within the framework of the H-BF model (i.e., the envelope function theory with C-2v perturbations at the interfaces) yield fair agreement with the experimental results.