Carbon doping of cubic GaN under gallium-rich growth conditions

摘要

Successful p-type doping of cubic GaN by carbon grown under Ga-rich conditions is reported with maximum hole concentration of 6 x 10~(18) cm~(-3) and hole mobility of 19 cm~2/Vs at room temperature, respectively. Cubic GaN:C was grown by rf-plasma assisted molecular beam epitaxy (MBE) on a semiinsu-lating GaAs (001) substrate (3 inches wafer). C-doping of the c-GaN was achieved by e-beam evaporation of a graphite rode with an C-flux of 1 x 10~(12) cm~(-2) s~(-1). Optical microscopy, Hall-effect measurements and room temperature photoluminescence were used for the investigation of the morphological, electrical and optical properties of cubic GaN: C. Under Ga-rich growth conditions most part of the carbon atoms were incorporated substitutially on N-site giving p-type conductivity. Our results verify that effective p-type doping of c-GaN can be achieved under Ga-rich growth conditions.