Influence of Threading Dislocations on the Luminescence Efficiency of GaN Heteroepitaxial Layers
异质外延GaN中穿透位错对材料发光效率的影响

We study the relationship between microstructure and luminescence efficiency for GaN heteroepitaxial films by cathodoluminescence (CL),transmission electron microscopy,and X-ray diffraction.Even though threading dislocations in GaN epitaxial layers have been demonstrated to be effective nonradiative recombination centers,the CL band edge peak intensity does not decrease as the dislocation density increases.The luminescence efficiency of GaN is found to be affected both by the grain size of the mosaic structural GaN formed by two-step growth and by the bend extent of dislocations formed during the coalescence of sub-grains.