Delta-doping optimization for high quality p-type GaN

Delta (delta-) doping is studied in order to achieve high quality p-type GaN. Atomic force microscopy, x-ray diffraction, photoluminescence, and Hall measurements are performed on the samples to optimize the delta-doping characteristics. The effect of annealing on the electrical, optical, and structural quality is also investigated for different delta-doping parameters. Optimized pulsing conditions result in layers with hole concentrations near 10(18) cm(-3) and superior crystal quality compared to conventional p-GaN. This material improvement is achieved thanks to the reduction in the Mg activation energy and self-compensation effects in delta-doped p-GaN. (c) 2008 American Institute of Physics. [DOI: 10.1063/1.3000564]