Optical polarization characteristics of m-plane InGaN/GaN quantum well structures and comparison with experiment

The optical polarization characteristics of the light emission in non-polar m-plane InGaN/GaN quantum well (QW) structures were theoretically investigated using the multiband effective-mass theory. The optical anisotropy of m-plane QW structure is ranging from 0.65 at 440 nm to 0.83 at 560 nm at the sheet carrier density of N 2 D = 15 × 10 12 cm - 2 and is found to decrease gradually with increasing carrier density, which is in good agreement with the experimental result. The decrease in the optical anisotropy can be explained by the fact that the y ′-polarized matrix element decreases with increasing k while the x ′-polarized matrix element gradually increases. Also, the decreasing rate of the QW structure with a smaller In composition is shown to be greater than that of the QW structure with a larger In composition.