title: Differences in the nanoscale electrical properties of GaN films grown on sapphire and ZnO substrates by molecular beam epitaxy.
abstract: Gallium nitride (GaN) films were grown on sapphire and zinc oxide (ZnO) single crystal substrates using plasma-assisted molecular beam epitaxy. As ZnO for GaN have a better lattice match, the coverage ratio of the GaN (002) plane on the ZnO substrate was significantly higher by about 45%. According to conducting atomic force microscopy and scanning surface potential microscopy measurements, the surface of GaN films grown on the ZnO substrate had two excellent physical characteristics: (a) an 18% reduction of the high contact current region, and (b) a highly uniform work function distribution. Therefore, for future applications in GaN-based light-emitting diodes, the use of ZnO as a substrate will prolong the luminescence lifetime and enhance the luminescent monochromaticity.
authors.affiliation: Department of Electrophysics, National Chiayi University, Chiayi, 600, Taiwan.
authors.forename: Sy-Hann
authors.identifier: http://orcid.org/0000-0001-9671-1584
authors.initials: SH
authors.lastname: Chen
authors.affiliation: Department of Electrophysics, National Chiayi University, Chiayi, 600, Taiwan.
authors.forename: Chiung-Wu
authors.initials: CW
authors.lastname: Su
authors.affiliation: Department of Electrophysics, National Chiayi University, Chiayi, 600, Taiwan.
authors.forename: Li-Hsin
authors.initials: LH
authors.lastname: Chang
authors.affiliation: Department of Electrophysics, National Chiayi University, Chiayi, 600, Taiwan.
authors.forename: Tzung-Han
authors.initials: TH
authors.lastname: Tsai
keywords: conducting atomic force microscopy; gallium nitride; scanning surface potential microscopy; zinc oxide