ABSTRACTThe electrical and luminescent properties of Mg-doped GaN films grown by molecular beam epitaxy (MBE) using ammonia as the nitrogen source have been investigated. Due to their different growth environments, the Mg-doped GaN films grown by MBE using ammonia exhibited properties that were different from similar films grown by metal-organic chemical vapor deposition (MOCVD). It has been found that the introduction of positive charges during growth is important in the achievement of p-type Mg-doped GaN grown by MBE using ammonia. With the introduction of a moderate nitrogen plasma, we have achieved p-type Mg-doped GaN films with a hole density of 4×1017 cm−3 and a mobility of 15 cm2/V-s at room temperature.
Vacancy-type defects in Mg-doped GaN grown by ammonia-based molecular beam epitaxy probed using a monoenergetic positron beam