Characterization of Mg-Doped GaN Micro-Crystals Grown by Direct Reaction of Gallium and Ammonia

Mg-doped GaN micro-crystals were prepared by the direct reaction of metal gallium and ammonia using magnesium chloride (MgCl2) as Mg doping source. The growth of microcrystalline hexagonal GaN was clearly found from scanning electron microscopy and TEM measurements. The grain size of Mg-doped GaN crystals was larger than that of undoped GaN. Room temperature PL and CL spectra for Mg-doped GaN micro-crystal showed the blue emission at 2.75 and 2.85 eV, respectively.