Deformation-induced defects were studied by means of positron lifetime measurements. Two lifetime components, 285 and 544ps, were attributed to dislocation-related defects and to vacancy clusters, respectively. By using annealing techniques, the dislocation-related component was found to consist of 2 more components. One of these annihilated after annealing at about 900C, while the other persisted even at 1100C. These were attributed to vacancy-like portions of dislocations and to dislocations themselves, respectively. The positron trapping rate due to dislocations increased upon cooling, and saturated below 80K. It was approximately proportional to the reciprocal of temperatures of between 100 and 300K. The results were interpreted in terms of shallow levels that originated from strain fields around dislocations, and in terms of the 1-dimensionality of the dislocations.

A.Kawasuso, M.Suezawa, M.Hasegawa, S.Yamaguchi, K.Sumino: Japanese Journal of Applied Physics, 1995, 34[I-9A], 4579-86