Correlation between Optical Polarization and Luminescence Morphology of (1122)-Oriented InGaN/GaN Quantum-Well Structures

Abstract

Quantization effects on optical polarization switching in (1122)-oriented InGaN/GaN quantum-well (QW) structures, which were not evident in the previous report by Ueda et al., have been firmly confirmed. The present study found that polarization ratios became more negative as the luminescence photon energy was decreased from 2.6 eV. Enhancement in optical polarization was found in thin QW structures, which is believed to be a result of quantization effects. Sample structures containing thick InGaN and AlGaN layers showed polarization ratios shifted towards positive values; these samples exhibited in-plane luminescence inhomogeneity with stripe morphologies parallel to [1100] and dark lines appearing at angles between 50 and 62° with respect to [1100].