Distribution of the Intensity of Recombination Radiation and of the Voltage Drop in Diffused p-n Junctions in Gallium Arsenide

Abstract

A description is given of a method which can be used to determine which regions in a crystal with a p-n junction emit recombination radiation. The method is based on the use of combined electrical and optical probes. It is shown that this method can only be applied to crystals which absorb their intrinsic recombination radiation. The method can be used not only to determine that region in which the light emission is concentrated, but also to estimate its electrical and optical properties (absorption coefficient, diffusion length, and carrier lifetime). The method was applied to diffused p-n junctions in gallium arsenide, which emitted infrared radiation. It was established that radiation was emitted mainly by that part of the p-type layer which adjoined the space-charge region of the p-n junction. The absorption coefficient of the recombination radiation in this region was 700 cm^-1, the diffusion length of the electrons was 4-6 µ, and the electron lifetime in the p-type region was 1.5 · 10^-8-3.5 · 10^-8 sec.