High optical polarization ratio of semipolar (202¯1¯)-oriented InGaN/GaN quantum wells and comparison with experiment

Abstract

Optical anisotropy properties of (202¯1¯)-plane wurtzite (WZ) InGaN/GaN quantum well (QW) structures were investigated using the multiband effective-mass theory and the non-Markovian model with many-body effects. The results were compared with those of non-polar (112¯0) a-plane InGaN/GaN QW structures. The In content dependence of the transition wavelength of the (202¯1¯)-plane QW structure is found to be very similar to that of (112¯0)-plane QW structure. The (202¯1¯)-plane shows slightly smaller y′-polarized spontaneous emission coefficient than that with the (112¯0)-plane. On the other hand, in the case of x′-polarization, the (202¯1¯)-plane QW structure has a larger spontaneous emission coefficient than the (112¯0)-plane QW structure. The in-plane optical anisotropies of both QW structures are shown to increase gradually with increasing transition wavelength or In content. The optical anisotropy of (202¯1¯)-oriented QW structure is ranging from 0.50 at 400 nm to 0.75 at 530 nm, which is in good agreement with the experimental result.