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Author Ke, Wen-Cheng ♦ Yang, Cheng-Yi ♦ Lee, Fang-Wei ♦ Chen, Wei-Kuo ♦ Huang, Hao-Ping
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ALUMINIUM ♦ CARRIERS ♦ DEPLETION LAYER ♦ DOPED MATERIALS ♦ FILMS ♦ GALLIUM NITRIDES ♦ INDIUM ♦ OXYGEN ♦ PHOTOELECTRON SPECTROSCOPY ♦ QUANTUM DOTS ♦ SPUTTERING ♦ TRAPS ♦ TUNNEL EFFECT ♦ VACANCIES ♦ X RADIATION ♦ ZINC OXIDES
Abstract 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 × 10{sup −4} Ω cm{sup 2} was achieved for a sample annealed at 500 °C for 30 s in nitrogen ambient and embedded with an InON nanodot interlayer with a nanodot density of 6.5 × 10{sup 8} cm{sup −2}. By contrast, a sample annealed in oxygen ambient exhibited non-Ohmic behavior. X-ray photoemission spectroscopy results showed that the oxygen vacancy (V{sub 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.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-10-21
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 118
Issue Number 15


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