The defects which were introduced by Zn diffusion were studied by measuring the photoluminescence and photo-emission spectra of Zn-diffused samples which had been fabricated by using a new diffusion technique. The results indicated that Zn diffusion generated broad emission bands, with energies ranging from 0.7 to 1eV, only in a surface layer with a thickness of less than about 100nm. It also left a P-rich layer with a very high Zn concentration and a thickness of less than about 20nm. It was suggested that Zn diffusion from a high-Zn concentration source, under P-rich conditions, occurred near to the surface and introduced deep centers which were responsible for the bands.

M.Wada, K.Sakakibara: Japanese Journal of Applied Physics, 1993, 32[2-4A], L469-72