The ampoule diffusion of Zn gave rise to donor-acceptor photoluminescence transitions with peak positions that depended upon the cooling rate after diffusion. Subsequent annealing in a Zn-free ambient caused a shift in the peak position. Luminescence peaks were found between 1.30 and 1.38eV. These peaks were attributed to transitions between various Zn interstitial donor levels and the Zn substitutional acceptor level. The luminescence data were correlated with secondary ion mass spectrometry and Schottky barrier capacitance-voltage measurements, and were found to be consistent with an earlier model in which Zn was supposed to diffuse as both an interstitial donor and a substitutional acceptor.

E.A.Montie, G.J.Van Gurp: Journal of Applied Physics, 1989, 66[11], 5549-53