Positron annihilation spectroscopy was used to study the effect of various growth conditions on vacancy formation in In- and N-polar InN grown by plasma-assisted molecular beam epitaxy. The results suggested that the structural quality of the material and limited diffusion of surface adatoms during growth dictate the In vacancy formation in low electron-density undoped epitaxial InN, while growth conditions and thermodynamics played a less important role, contrary to what was observed in, e.g., GaN. Furthermore, the results implied that in high quality InN, the electron mobility was likely limited not by ionized point defect scattering, but . rather by threading dislocations.

In Vacancies in InN Grown by Plasma-Assisted Molecular Beam Epitaxy. F.Reurings, F.Tuomisto, C.S.Gallinat, G.Koblmüller, J.S.Speck: Applied Physics Letters, 2010, 97[25], 251907