Changes in the intensity of the Cu photoluminescence center (no-phonon peak of 1.014eV), as a function of annealing time, were measured in p-type float-zone crystals which had been diffused with various concentrations of Cu at 700C, followed by rapid cooling to room temperature. It was found to be essential to assume the presence of at least one precursor species of the Cu photoluminescence center in order to explain the annealing behavior of the photoluminescence intensity. Almost the same quantity of precursor, as that of the Cu photoluminescence center, was estimated to remain in as-cooled crystals. The formation energy of the Cu photoluminescence center was 0.57eV, and the dissociation energy was 0.63eV. It was proposed that there was a correlation between the precursor of the Cu photoluminescence center, and a deep-level transient spectroscopy center which was located at Ec - 0.15eV.

Copper Complexes in Silicon M.Nakamura, H.Iwasaki: Journal of Applied Physics, 1999, 86[10], 5372-5