Characteristics of Polarized Light Emission in $a$-Plane GaN-Based Multiple Quantum Wells

In this paper, we investigated polarized light emission properties on a series of a-plane GaN/AlGaN multiple quantum wells grown on r-plane sapphire substrates with various well widths by using the polarization-dependent photoluminescence measurement. To clarify reasons of polarization properties in light emission, we applied the 6 × 6 k·p model to simulate the E-K dispersion relationship and wave functions to obtain optical transitions of different polarized emissions. According to our results, the sub-bands of |Y>;-like states are raised toward the top of the valence sub-band level with increasing the well width. And the optical matrix element of y-polarized light emission will dominate the optical transition, leading to the increase of degree of polarization in the thicker well.