Thermal annealing effect on material characterizations of β-Ga2O3 epilayer grown by metal organic chemical vapor deposition

In this work, a single-crystalline beta-Ga2O3 epilayer was grown on (0001) sapphire at low temperature by low-pressure metal organic chemical vapor deposition. The optimized parameters for the chamber pressure, oxygen flow, and growth temperature were 15 Torr, 200 sccm, and 500 degrees C, respectively. The beta-Ga2O3 epilayer was fabricated as a metal-semiconductor-metal solar-blind deep ultraviolet photodetector. Due to the gallium oxide grown at low temperature, the as-grown beta-Ga2O3 epilayer was annealed at 800 degrees C in atmosphere or in a nitrogen environment. The effects of defects of the beta-Ga2O3 epilayer before and after N-2 annealing were studied using x-ray diffraction system, cathodoluminescence at differential temperature, and Hall measurement. The beta-Ga2O3 epilayer that was N-2 annealed for 15min presented better photodetector performance than the as-grown beta-Ga2O3 epilayer. The annealed epilayer exhibited a dark current of 1.6 x 10(-13) A under 5 V bias. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773247]