Interband and intersubband optical characterization of semipolar ( 11 2 ¯ 2 ) -oriented GaN/AlN multiple-quantum-well structures

We report on semipolar GaN/AlN multiple-quantum-well structures grown on m -plane sapphire by plasma-assisted molecular-beam epitaxy. Optical investigation confirms a significant reduction in the quantum-confined Stark effect, in agreement with theoretical calculations, which predict an internal electric field between 0.6 and − 0.55 MV / cm in the quantum wells, depending on the strain state. With respect to polar materials, the reduction in the internal electric field results in a substantial redshift of the intersubband energy.