Photoluminescence Intensity and Spectral Distribution of GaN Films on SiC Substrates — The Dependence on Dislocation Density and Structure

Abstract

GaN samples were grown having threading dislocation density in the range of 5.5 × 108 to 5 × 1010 cm—2. The decrease of the band edge luminescence which occurs as the dislocation density increases is measured and numerically simulated with minority carrier diffusion length L = 90 nm. The emitted band edge luminescence intensity and wavelength has a spatial distribution which depends on the dislocation structure in the crystal. An observed trend toward lower energy of the band edge peak as the dislocation density increases indicates that some relaxation of the SiC/GaN interfacial misfit stress occurs through the defects.