Optical anisotropy in nonpolar (101̄0)-oriented m-plane GaN/AlGaN quantum wells and comparison with experiment

Abstract

Optical anisotropy in nonpolar ($10\overline{1}0$)-oriented m-plane GaN/InGaN quantum wells was investigated using the multi-band effective-mass theory. The optical matrix element near the Γ point (k_||=0) is shown to increase with increasing polarization angle ϕ’. The anisotropy calculated at the Γ point (k_||=0) is nearly 1 and it rapidly decreases with increasing in-plane wave vector. The reduction of the anisotropy at a large k_|| is attributed to the fact that the state of the first subband is equally mixed of |X〉 and |Y〉 at a large k_||. The photoluminescence intensity increases with ϕ’, becomes a maximum at ϕ’=π/2, and decreases again when ϕ’ further increases. The theoretical result is found to be in good agreement with the experimental results.