Donor binding energies determined from temperature dependence of photoluminescence spectra in undoped and aluminum-doped beta SiC films

Abstract

Measurements of the temperature dependence of N-Al donor-acceptor pair photoluminescence spectra in cubic SiC films demonstrate that the thermal activation energy for the nitrogen donors is equivalent to the 54 meV binding energy for nitrogen determined from the spectral energies of the sharp-line close pair spectra. It follows that the 15–20 meV donor which dominates the electrical properties of n-type films is not isolated, substitutional nitrogen. Spatial variations observed in the intensity of a new 2.368 eV luminescence band demonstrate that the radiative recombination centers are inhomogeneously distributed in the films.