The distributions of di-vacancies, with a singly negative charge state, which were produced by fast ion irradiation (1MeV) were studied by means of deep-level transient spectroscopy. The di-vacancy concentration profiles which arose from irradiation with 1.3, 2.1, 3.2 or 4.8MeV protons to a fluence of 5 x 109/cm2, as well as with 16.3MeV 16O and 32.6MeV 32S (to fluences of 2 x 107 and 107/cm2, respectively) were compared with calculated values of the average depth and straggling of the elastic energy deposition distribution. A comparison was also made with the defect profiles which were obtained at 92K. The effect of straggling and diffusion, of initially created Frenkel pairs, upon the width of the defect distribution was considered. It was shown that diffusion accounted for a 3 broadening (full width at half maximum) of the di-vacancy distribution under irradiation at room temperature.

A.Hallén, B.G.Svensson: Radiation Effects and Defects in Solids, 1994, 128[3], 179-86