Growth of Polycrystalline GaN on Silicon (001) Substrates by RF Plasma Chemical Vapor Deposition with ZnO Buffer Layer

Abstract

Polycrystalline GaN was grown at 650 °C on silicon (001) substrates by radio frequency (rf) plasma enhanced chemical vapor deposition (PECVD) with ZnO buffer layer. X-ray diffraction (XRD) measurements revealed that the ZnO buffer layer was oriented along the (0002) planes while GaN thin films were along (0002) and (101-1) planes. The ZnO buffer layer was found to be effective for the enhanced photoluminescence (PL) from the polycrystalline GaN. The low temperature (24 K) PL spectrum was dominated by the band-edge luminescence peaking at about 3.35 eV without appreciable deep level emissions. Temperature-dependent PL measurements indicated that the band-edge PL spectrum red-shifted with increasing temperature, where the nonradiative recombination is considered to be more dominant. Slope between the PL photon energy and the measurement temperature higher than 200 K up to room temperature well agreed with that of polycrystalline GaN by molecular beam epitaxy (MBE).