Influence of layer thickness on the formation of In vacancies in InN grown by molecular beam epitaxy

Abstract

We have used a low-energy positron beam to identify In vacancies in InN layers grown on Al2O3 by molecular beam epitaxy. Their concentration decreases from ∼5×1018 to below 1016 cm−3 with increasing layer thickness (120–800 nm). The decrease in the vacancy concentration coincides with the increase in the electron Hall mobility, suggesting that In vacancies act as electron scattering centers.