Mg doping in (1 1¯ 0 1)GaN grown on a 7° off-axis (0 0 1)Si substrate by selective MOVPE

Mg doping was attempted in (1 1¯ 0 1)GaN grown on a patterned (0 0 1)Si by selective metal-organic vapor phase epitaxy (MOVPE). The source material for the Mg doping was EtCp2Mg and the electrical properties were studied on samples with different doping levels. All samples showed p-type conduction. However, the hole concentration was decreased by the Mg doping at low doping levels followed by an increase at high doping levels. The activation energy was around 106–130 meV depending on the doping level, which was larger than that found in undoped or carbon-doped samples. The AFM images showed gradual change in the surface structure in accordance with the Mg-doping level. The variation of the optical spectra was discussed in relation to the Mg-doping levels.