Piezoelectric and Spontaneous Polarization Effects on Many-Body Optical Gain of Wurtzite InGaN/GaN Quantum Well with Arbitrary Crystal Orientation

The piezoelectric (PZ) and spontaneous (SP) polarization effects on the optical gain of wurtzite (WZ) InGaN/GaN quantum wells (QWs) with an arbitrary crystal orientation were investigated using the non-Markovian gain model with many-body effects. The difference of the SP polarization between the well and the barrier is shown to be very small and neglecting SP polarization is a good approximation in InGaN/GaN QW system. A self-consistent model with PZ and SP polarization effects shows that many-body optical gain is significantly reduced near θ=0°, compared to the flat-band model. This can be explained by the reduction of the matrix elements near θ=0° due to PZ and SP polarization. It was found that PZ and SP polarization effects are nearly negligible for crystal angles above θ=50°.