The effect of reabsorbed radiation on the minority-carrier diffusion length in GaAs

Reported in this paper are the first experiments designed to separate the effects of reabsorbed recombination radiation (RRR) and diffusing minority carriers on the measured minority-carrier diffusion length. From light spot scan experiments on bevelled samples of p-type Ge-doped GaAs it was found that for p-layer thicknesses up to two diffusion lengths (10–20 μm) carriers created by RRR represent less than 10% of the total carriers diffusing from a generating source (illumination of p-n junction injection). Thus for measurements and structures of interest carriers created by RRR play no substantial role.