Incorporation site of Tb in GaN studied by Rutherford-backscattering ion channelling measurements and x-ray absorption fine-structure analysis

We report single-crystalline growth of Tb-doped GaN grown by gas source molecular beam epitaxy using NH3 as a nitrogen source, and the incorporation site of Tb in GaN. It was found that most of the Th atoms are substitutionally incorporated into the Ga lattice site by Rutherford-backscattering ion channelling and extended x-ray absorption fine-structure analysis. Photoluminescence spectra, which show sharp peaks originating from 4f intra-atomic transitions of Tb3+ ions, with near-band-edge emission of GaN, were observed from the film whose Tb content was roughly estimated to be 2%, and their properties are discussed.