Metal modulation epitaxy growth for extremely high hole concentrations above 10 19 cm − 3 in GaN

The free hole carriers in GaN have been limited to concentrations in the low 10 18 cm − 3 range due to the deep activation energy, lower solubility, and compensation from defects, therefore, limiting doping efficiency to about 1%. Herein, we report an enhanced doping efficiency up to ∼ 10 % in GaN by a periodic doping, metal modulation epitaxy growth technique. The hole concentrations grown by periodically modulating Ga atoms and Mg dopants were over ∼ 1.5 × 10 19 cm − 3 .