標題: Trap-assisted tunneling in aluminum-doped ZnO/indium oxynitride nanodot interlayer Ohmic contacts on p-GaN
作者: Ke, Wen-Cheng
Lee, Fang-Wei
Yang, Cheng-Yi
Chen, Wei-Kuo
Huang, Hao-Ping
電子物理學系
Department of Electrophysics
公開日期: 21-Oct-2015
摘要: This study developed an Ohmic contact formation method for a ZnO:Al (AZO) transparent conductive layer on p-GaN films involving the introduction of an indium oxynitride (InON) nanodot interlayer. An antisurfactant pretreatment was used to grow InON nanodots on p-GaN films in a RF magnetron sputtering system. A low specific contact resistance of 1.12 x 10(-4) Omega cm(2) was achieved for a sample annealed at 500 degrees C for 30 s in nitrogen ambient and embedded with an InON nanodot interlayer with a nanodot density of 6.5 x 10(8) cm(-2). By contrast, a sample annealed in oxygen ambient exhibited non-Ohmic behavior. X-ray photoemission spectroscopy results showed that the oxygen vacancy (V-o) in the InON nanodots played a crucial role in carrier transport. The fitting I-V characteristic curves indicated that the hopping mechanism with an activation energy of 31.6 meV and trap site spacing of 1.1 nm dominated the carrier transport in the AZO/InON nanodot/p-GaN sample. Because of the high density of donor-like oxygen vacancy defects at the InON nanodot/p-GaN interface, positive charges from the underlying p-GaN films were absorbed at the interface. This led to positive charge accumulation, creating a narrow depletion layer; therefore, carriers from the AZO layer passed through InON nanodots by hopping transport, and subsequently tunneling through the interface to enter the p-GaN films. Thus, AZO Ohmic contact can be formed on p-GaN films by embedding an InON nanodot interlayer to facilitate trap-assisted tunneling. (C) 2015 AIP Publishing LLC.
URI: http://dx.doi.org/10.1063/1.4933273
http://hdl.handle.net/11536/128405
ISSN: 0021-8979
DOI: 10.1063/1.4933273
期刊: JOURNAL OF APPLIED PHYSICS
Volume: 118
Issue: 15
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