Publications

Ga vacancies and grain boundaries in GaN

Oila, J.; Saarinen, K.; Wickenden, A.E.; Koleske, Daniel K.; Henry, R.L.; Twigg, M.E.

Epitaxial Si-doped GaN layers were studied using a low-energy positron beam, where the grain size varies from 0.2 to 2-5 μm. The concentration of the negatively charged Ga vacancies was found to be independent of the grain size, which showed that Ga vacancies exist in the grain interior. Positrons were also observed to get trapped also at other negatively charged centers.