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Differences in the nanoscale electrical properties of GaN films grown on sapphire and ZnO substrates by molecular beam epitaxy
Author(s) -
Chen SyHann,
Su ChiungWu,
Chang LiHsin,
Tsai TzungHan
Publication year - 2017
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.22858
Subject(s) - molecular beam epitaxy , materials science , sapphire , gallium nitride , optoelectronics , luminescence , substrate (aquarium) , light emitting diode , epitaxy , nanoscopic scale , diode , nanotechnology , optics , layer (electronics) , laser , oceanography , physics , geology
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.