A detailed analysis was made of the photo-induced current transients of variously grown Cl-doped samples at temperatures ranging from 100 to 140K. It was found that analysis of the transients was crucial. By using the conventional 2-gate technique, only one trap (with misleading trap parameters) could be identified in each sample. Analysis of the transients by using the authors' recently described regularization method identified 3 traps in each sample. Only one of these traps led to an activation energy and to a cross-section which was approximately the same for the various samples. The other 2 traps in each sample depended upon the growth technique.

C.Eiche, D.Maier, D.Sinerius, J.Weese, K.W.Benz, J.Honerkamp: Journal of Applied Physics, 1993, 74[11], 6667-70