Photoluminescence from deep centers in GaAs

Sharp line structure attributable to phonon assisted radiative emission has been observed in the 6 K photoluminescence spectra from deep centers in bulk samples of chromium doped GaAs. Two luminescence bands at 0.56 and 0.8 eV have been observed and both bands exhibit evidence of phonon assisted radiative recombination. An exploration of these luminescence bands in terms of excited state to ground state transitions of Cr³⁺ and Cr²⁺ ions is proposed.