Thermal transport of charge and polarization of 1.2-eV luminescence broad band in uniaxially strained n-GaAs:Te

Abstract

The effect of temperature on the pressure-induced polarization of the photoluminescence broad band related to VGaTeAs complexes in GaAs:Te is analyzed. It is shown that, within a certain temperature range, the pressure-induced difference in the activation energy of thermal emission of holes for dissimilarly oriented complexes leads to an abrupt increase in the integral polarization of radiation caused by recombination of free electrons with holes localized at these complexes compared to polarization at lower temperatures. In the samples subjected to 10-kbar pressure applied along the [111] axis, the described behavior of polarization was observed in the temperature range from 140 to 190 K. The results obtained validate the previously suggested model of a set of defects that give rise to the luminescence band under study. Fitting results of calculations to experimental data enabled us to correct the values of a number of the parameters of defects and to estimate a pressure-induced change in the activation energy of the thermal emission of holes from the defects with different orientation.