High hole concentration Mg doped a-plane GaN with MgN by metal–organic chemical vapor deposition

• High hole concentration Mg doped a-plane GaN with MgN was achieved by metal–organic chemical vapor deposition.
• Nonpolar p-type GaN layers using MgN interlayers exhibited improved surface morphology, with typical stripe features along the [0 0 0 1] direction, and reduced faceted triangular pits on the surface.
• High quality Mg doped a-plane GaN was achieved, by insertion of two pairs of MgN interlayers.

Mg doped a-plane GaN layers with MgN interlayers were grown on r-plane sapphire substrates by metal–organic chemical vapor deposition. Nonpolar Mg doped a-plane GaN without MgN exhibited a rough surface morphology, with both various sized, and large number of faceted pits. Meanwhile, nonpolar p-type GaN layers using MgN exhibited improved surface morphology, with typical stripe features along the [0 0 0 1] direction, and reduced faceted triangular pits on the surface, leading to increased hole concentration and crystal quality. The effect of insertion of MgN interlayers and their characteristics in Mg doped a-plane GaN were estimated by Hall-effect measurement, atomic force microscopy (AFM), cathode luminescence (CL), X-ray diffraction (XRD), and transmission electron microscope (TEM) measurement.