Comparison of the polarizations of the 1.2-eV photoluminescence band in n-GaAs : Te under uniaxial pressure and resonance polarized excitation

It is shown that the photoluminescence (PL) band at 1.2 eV in n-GaAs:Te, wh ich is associated with emission from VGaTeAs complexes with reorienting Jah n-Teller distortions, also includes a contribution from nonreorienting defe cts. The optical dipole parameters are almost the same for both types of de fects. Expressions relating the polarization of the PL band at 1.2 eV under uniaxial pressure and polarized resonant excitation to dipole parameters a nd to relative contributions to emission from reorienting and nonreorientin g defects are derived. A procedure is developed for evaluating these charac teristics by analyzing experimental data, and the contributions from each k ind of defects to the PL band at 1.2 eV were found to be comparable, even t hough they vary from sample to sample. The obtained angles characterizing t he position of the axes of optical dipoles associated with the defects in l ight-absorbing and light-emitting states indicate that, in the former state , the effects of donors and the Jahn-Teller distortion on the vacancy orbit als of the VGaTeAs complex are comparable, while in the latter, the effect of distortion is dominant. (C) 2000 MAIK "Nauka/Interperiodica".