Porous single-crystal GaN films obtained by direct top-down nitridation of bulk and film β-Ga2O3

Abstract We report here the preparation of porous single-crystal GaN films by direct top-down high temperature nitridation of β-Ga2O3. It is found that, although the crystallographic orientations of the original β-Ga2O3 samples are different, the GaN films converted from both bulk (200) β-Ga2O3 single crystal and (−201) β-Ga2O3 film have the same (0002) orientation and show no obvious stress. And we also found that the crystal quality of converted GaN strongly depends on the crystal quality of β-Ga2O3. In particular, we have successfully converted β-Ga2O3 film entirely to single-crystal GaN porous film on sapphire, and the self-separation happens naturally between the porous GaN film and sapphire.