Strain-Induced Effects on the Electronic Band Structures in GaN/AlGaN Quantum Wells: Impact of Breakdown of the Quasicubic Approximation in GaN

Recently, we performed reflectance spectroscopy for nonpolar and semipolar bulk GaN substrates under uniaxial stress and experimentally determined all the exciton deformation potentials in GaN. Our findings indicated a breakdown of the quasicubic approximation. Herein its impact on the electronic band structures in GaN/AlGaN strained quantum wells is theoretically investigated. The calculated results significantly differ from those using the widely accepted exciton deformation potentials. A simplified Hamiltonian is given to describe the in-plane optical polarization properties of GaN/AlGaN quantum wells.