DIFFUSION LENGTH OF PHOTOEXCITED CARRIERS IN GAN

When additional carriers are introduced in a material with a non unifo rm concentration, they tend to diffuse on a scale given by their diffu sion length. This parameter can be measured by different methods. Depe nding on the conditions, different values can be found as the recombin ation mechanisms differ. In this paper, we present the situation in Ga N with various experiments including the photocarrier grating method, photoluminescence and the spectral response in photoconductors. We sho w that the diffusion length varies from 0.1 mu m to a few mu m dependi ng on experimental conditions. The interpretation is given based on th e diffusion equations and on the analysis of the recombinations. (C) 1 997 Elsevier Science S.A.