In-plane optical anisotropy of symmetric and asymmetric (001) GaAs/Al(Ga)As superlattices and quantum wells

Two sensitive polarized spectroscopies, reflectance difference spectroscopy and photocurrent difference spectroscopy, are used to study the characteri stic of the in-plane optical anisotropy in the symmetric and the asymmetric (001) GaAs/Al(Ga)As superlattices (SLs). The anisotropy spectra of the sym metric and the asymmetric SLs show significant difference: for symmetric on es, the anisotropies of the 1HH-->1E transition (1H1E) and 1L1E are dominan t, and they are always approximately equal and opposite; while for asymmetr ic ones, the anisotropy of 1H1E is much less than that of 1L1E and 2H1E, an d the anisotropy of 3H2E is very strong. The calculated anisotropy spectra within the envelope function model agree with the experimental results, and a perturbation approach is used to understand the role of the electric fie ld and the interface potential in the anisotropy. (C) 2001 American Institu te of Physics.