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p-Cu2O-shell/n-TiO2-nanowire-core heterostucture photodiodes

Tsung-Ying Tsai1, Shoou-Jinn Chang1, Ting-Jen Hsueh2*, Han-Ting Hsueh2, Wen-Yin Weng1, Cheng-Liang Hsu3 and Bau-Tong Dai2

Author Affiliations

1 Institute of Microelectronics and Department of Electrical Engineering, Center for Micro/Nano Science and Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, 701, Taiwan

2 National Nano Device Laboratories, Tainan, 741, Taiwan

3 Department of Electronic Engineering, National University of Tainan, Tainan, 700, Taiwan

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Nanoscale Research Letters 2011, 6:575  doi:10.1186/1556-276X-6-575

Published: 31 October 2011


This study reports the deposition of cuprous oxide [Cu2O] onto titanium dioxide [TiO2] nanowires [NWs] prepared on TiO2/glass templates. The average length and average diameter of these thermally oxidized and evaporated TiO2 NWs are 0.1 to 0.4 μm and 30 to 100 nm, respectively. The deposited Cu2O fills gaps between the TiO2 NWs with good step coverage to form nanoshells surrounding the TiO2 cores. The p-Cu2O/n-TiO2 NW heterostructure exhibits a rectifying behavior with a sharp turn-on at approximately 0.9 V. Furthermore, the fabricated p-Cu2O-shell/n-TiO2-nanowire-core photodiodes exhibit reasonably large photocurrent-to-dark-current contrast ratios and fast responses.