Experimental studies were made of H-implanted GaN and He- and Li-implanted

ZnO. The ion energies were varied from 100 to 850keV, and the implantation

fluences ranged from 5 x 1013 to 1018/cm2. In addition, conventional and flash

annealing at 500 to 1400C were performed on the ZnO samples. The data obtained

using a slow positron beam showed that vacancy clusters were formed in asimplanted

samples with fluences above 1017/cm2. Below this value, only single

vacancies were detected after implantation, but vacancy clusters could be formed

and subsequently dissociated by thermal annealing.

Vacancy Profiles and Clustering in Light-Ion-Implanted GaN and ZnO.

F.Tuomisto: Applied Surface Science, 2008, 255[1], 54-7