Optical and structural properties of In 0.08GaN/In 0.02GaN multiple quantum wells grown at different temperatures and with different indium supplies

Abstract

The optical and structural properties of In 0.08Ga 0.92N/In 0.02Ga 0.98N multiple quantum wells (MQWs) grown at different temperatures and with different supplies of indium were analyzed by atomic force microscopy and spectrally resolved cathodoluminescence (CL). By comparing the contrasts of monochromatic CL images with high-resolution secondary-electron images of the sample surface, it is shown that almost all contrasts of the CL images can be explained by lateral inhomogeneities of both the thickness and the InN mole fraction of the InGaN layers. Dark contrasts in the CL images solely related to dislocations were not observed, indicating very weak nonradiative recombination correlated with threading dislocations in the InGaN quantum wells. The lateral inhomogeneities of layer thickness and indium incorporation depend strongly on the growth conditions. © 2010 TMS.