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, which is associated with emission from VGaTeAs complexes with reorienting Jahn-Teller distortions, also includes a contribution from nonreorienting defects. The optical dipole parameters are almost the same for both types of defects. Expressions relating the polarization of the PL band at 1.2 eV under uniaxial pressure and polarized resonant excitation to dipole parameters and to relative contributions to emission from reorienting and nonreorienting defects are derived. A procedure is developed for evaluating these characteristics by analyzing experimental data, and the contributions from each kind of defects to the PL band at 1.2 eV were found to be comparable, even though they vary from sample to sample. The obtained angles characterizing the position of the axes of optical dipoles associated with the defects in light-absorbing and light-emitting states indicate that, in the former state, the effects of donors and the Jahn-Teller distortion on the vacancy orbitals of the VGaTeAs complex are comparable, while in the latter, the effect of distortion is dominant.