Electroluminescence and Cathodoluminescence of p-n Junctions in GaAs

Abstract

An investigation was made of the spectral distribution of the impurity (extrinsic) recombination radiation of diffused p-n junctions made of n-type GaAs crystals with a range of defect concentrations. The impurity luminescence region included bands whose maxima were located at 0.99-1.06, 1.14-1.18, 1.21-1.29, 1.36, and 1.396 eV. The 1.396 eV band was ~kT wide at 80°K and it was attributed to radiative recombination in the space-charge region of the p-n junction. A comparison of the luminescence spectra obtained by injection through the p-n junction and by electron bombardment of different regions of the junction showed that the 1.0 and 1.28 eV bands originated from the n-type region in the p-n junction. The luminescence spectrum of this region differed from the spectrum of the n-type region far from the junction. This gave rise to a difference between the luminescence spectrum of the p-n junctions and the cathodoluminescence spectrum of GaAs subjected to heat treatment.