OPTICAL CHARACTERISTICS OF 1.18-EV LUMINESCENCE BAND COMPLEXES IN N-GAAS-SN(SI) - RESULTS OF A PHOTOLUMINESCENCE STUDY WITH POLARIZED RESONANT EXCITATION

Experimental values of the polarization of the low-temperature lumines cence from the VGaSnGa and VGaSiGa complexes in n-GaAs under condition s of resonant excitation by polarized light propagating along the [110 ] or [100] crystal axis are compared with expressions obtained in the classical dipole approximation for defects with triclinic or monoclini c symmetry. It is shown that the rotator fraction in the superposition of rotator and oscillator contributions to the emission of the comple xes is 17-18%. The direction of the axis of these dipoles, which match es the experimental data, is consistent with the assumption that the e ffect of the donor on the vacancy orbitals of a hole localized in the complex is lower than that of the Jahn-Teller effect. The resulting sy mmetry of the complex may be monoclinic or triclinic. In either case, deviation of the optical dipole axis of the complex from the dipole ax is of an isolated V-Ga vacancy distorted as a result of the Jahn-Telle r effect is lower for the VGaSnGa and VGaSiGa complexes than for VGaTe As complexes. This means that the effect of the donor on the electron structure of the VGaTeAs complexes is greater than in the VGaSnGa and VGaSiGa complexes. This correlates with the difference in the donor po sition in these complexes. (C) 1998 American Institute of Physics.