Dislocation effect on light emission efficiency in gallium nitride

We modify the model of nonradiative carrier recombination on threading dislocation cores [Z. Z. Bandić, P. M. Bridger, E. C. Piquette, and T. C. McGill, Solid-State Electron. 44, 221 (2000)] to estimate quantitatively the light emission efficiency in GaN as a function of the dislocation density and nonequilibrium carrier concentration. The model predictions are in good agreement with available data on the minority carrier diffusion length in GaN. The dislocation density must be reduced, at least, down to ∼107 cm−2 in order to provide a light emission efficiency close to unity. The n-type background doping is found to be favorable for the further efficiency improvement.