The electrical properties of GaN epilayers grown by metal-organic chemical vapour deposition using the indium-surfactant method were investigated by means of Hall measurements, photoluminescence and mono-energetic positron annihilation spectroscopy. The background electron concentration in GaN exhibited a minimum of 5.21 x 1016/cm3 for a trimethylindium flow of 20µmol/min. A decrease in electron concentration with increasing trimethylindium flow was attributed to an increase in the density of complex defects involving the Ga vacancy (VGa) compensating the electrons. It was suggested that the increase in electron concentration at a high trimethylindium flow was caused by the formation of N vacancies (VN), acting as shallow donors. Competition between the two mechanisms could govern the variation in electron concentration with increasing trimethylindium flow. A downward trend in electron mobility with increasing trimethylindium flow was also observed.

The Influence of Indium Surfactant on the Electrical Properties of GaN Epilayers Grown by Metal-Organic Chemical Vapour Deposition. J.Song, F.J.Xu, Z.L.Miao, S.Huang, Y.Wang, X.Q.Wang, B.Shen, X.B.Qin, B.Y.Wang, X.Q.Shen, H.Okumura: Journal of Physics D, 2010, 43[14], 145402