A comparative study on Be and Mg doping in GaN films grown using a single GaN precursor via molecular beam epitaxy

Doping characteristics of Mg and Be in GaN films grown using a new single GaN precursor via molecular beam epitaxy were investigated. X-ray diffraction analysis confirmed that the GaN lattice expands or contracts with Mg or Be doping due to their differences in the size with respect to Ga. The c-axis oriented growth mode has shifted to the basal-plane orientation as Mg increases. Semi-insulating electrical resistivities were observed in the as-grown films due to hydrogen passivation of the dopants. The major bonding configurations were Mg-H and Mg-H-Mg in GaN:Mg. However, Be-H-Be bonding was dominant over Be-H bonding in the GaN:Be films. The annealing behaviors of the films were different between GaN:Mg and GaN:Be films. They were discussed with the different passivation bonding configurations.