High-temperature epitaxial growth ( > 1200 degrees C) of GaN using Ga2O vapor and NH3 was performed to increase the crystal growth rate and improve crystal qualities such as surface morphology, crystallinity and oxygen incorporation. Results showed that the growth rate linearly increased with the increasing partial pressure of Ga2O, P-Ga2O, while the surface morphology and crystallinity degraded, and oxygen concentration in the epilayers increased. When the growth temperature increased, smooth GaN epilayers without the degradation of crystallinity could be grown even at high P-Ga2O, i.e. a high growth rate. In addition, the oxygen concentration decreased as the growth temperature was increased. (C) 2011 Elsevier B.V. All rights reserved.