Strong photoluminescence bands, at 1.34 and 1.45eV, were observed after the Li diffusion of various samples of n-type material at temperatures of between 400 and 600C. The photoluminescence bands were homogeneous throughout the bulk of the samples. They were never observed in originally p-type or semi-insulating material. A hole at Ev + 0.17eV was detected by means of deep-level transient spectroscopic measurements, and an acceptor level at Ev + 0.14eV was revealed by temperature-dependent Hall measurements of n-type material which had been converted to p-type by Li diffusion. It was suggested that LiGa-D acceptors were connected with compensation and photoluminescence bands.

B.H.Yang, T.Egilsson, S.Kristjánsson, J.Pétursson, H.P.Gislason: Materials Science Forum, 1994, 143-147, 839-44