Summary: | 碩士 === 國立臺灣師範大學 === 物理學系 === 104 === Graphene is a two-dimensional carbon material which consists of hexagonal array of carbon atoms. It has great potential to use as transparent conductive electrodes in UVCLED because of its high electron mobility, thermal conductivity, Mechanical, and low sheet resistance. Most of all, it has great transmittance at 280 nm or lower wavelength light. Therefore, high specific contact resistance between graphene and GaN (especial p-GaN) is the biggest challenge that used graphene as transparent conductive electrodes in UVCLED.
To decrease the specific contact resistance between graphene and GaN. In this study, we show two Buffer layers, including NiO and ITO dots to improve the adhesion and decrease the Schottky barrier. Our graphene is prepared by low pressure chemical vapor deposition, and p-GaN is provided by Epistar. One is deposit 2 nm NiO between graphene and p-GaN. The other way is add the etched ITO dots between graphene and p-GaN. Both experiments have annealed at 450℃in Ar ambient after add Buffer layer between graphene and GaN. And we used circular transmission line model (CTLM) and device tester to measure its characteristic and electrical resistance.
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