The effect of Ga/N flux ratio on surface morphology, incorporation of point defects and electrical transport properties of GaN films grown by plasma-assisted molecular beam epitaxy in a recently developed high-temperature growth regime was investigated. The homoepitaxial (0001) GaN films grown at ∼780–790 °C showed smoothest morphologies near the cross-over between N-rich and Ga-rich growth (0.75<Ga/N<1.1) contrasting previous observations for low-temperature growth. The higher-quality growth near Ga/N∼1 resulted from lower thermal decomposition rates and was corroborated by slightly lower Ga vacancy concentrations [VGa], lower unintentional oxygen incorporation, and improved electron mobilities. The consistently low [VGa], i.e., ∼1016 cm−3 for all films attribute further to the significant benefits of the high-temperature growth regime.
Koblmüller, G., Reurings, F., Tuomisto, F., & Speck, J. S. (2010). Influence of Ga/N ratio on morphology, Ga vacancies and electrical transport in (0001) GaN grown by plasma-assisted molecular beam epitaxy at high temperature. Applied Physics Letters, 97(19), 1-3. . https://doi.org/10.1063/1.3514236