Positron lifetime, photoluminescence and Hall measurements were performed in order to study undoped p-type material. A 314ps positron lifetime component was attributed to a VGa-related defect. Isochronal annealing studies showed that, at 300C, the 314ps positron lifetime component and 2 observed photoluminescence signals (0.777 and 0.797eV) disappeared; thus proving their correlation. The hole concentration (of about 2 x 1017/cm3) was observed to be independent of the annealing temperature. Although the residual acceptor was generally related to the VGa defect, at least for annealing temperatures above 300C, VGa was not the acceptor responsible for p-type conduction.

Gallium Vacancy and the Residual Acceptor in Undoped GaSb Studied by Positron Lifetime Spectroscopy and Photoluminescence. C.C.Ling, W.K.Mui, C.H.Lam, C.D.Beling, S.Fung, M.K.Lui, K.W.Cheah, K.F.Li, Y.W.Zhao, M.Gong: Applied Physics Letters, 2002, 80[21], 3934-6