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International Journal of Photoenergy
Volume 2015, Article ID 261372, 7 pages
Research Article

Hydrothermal Growth of Quasi-Monocrystal ZnO Thin Films and Their Application in Ultraviolet Photodetectors

1Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan
2Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan
3Department of Electrical Engineering, Wu Feng University, Chiayi 621, Taiwan

Received 28 October 2014; Revised 31 January 2015; Accepted 2 February 2015

Academic Editor: Shyh-Jer Huang

Copyright © 2015 Yung-Chun Tu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Quasi-monocrystal ZnO film grown using the hydrothermal growth method is used for the fabrication of Cu2O/ZnO heterojunction (HJ) ultraviolet photodetectors (UV-PDs). The HJ was formed via the sputtering deposition of p-type Cu2O onto hydrothermally grown ZnO film (HTG-ZnO-film). The effect of annealing temperature in the nitrogen ambient on the photoluminescence spectra of the synthesized ZnO film was studied. The optoelectronic properties of Cu2O/ZnO film with various Cu2O thicknesses (250–750 nm) under UV light (365 nm; intensity: 3 mW/cm2) were determined. The UV sensitivity of the HTG-ZnO-film-based UV-PDs and the sputtered ZnO-film-based UV-PDs were 55.6-fold () and 8.8-fold (), respectively. The significant gain in sensitivity ( = 630%) of the proposed ZnO-film-based device compared to that for the device based on sputtered film can be attributed to the improved photoelectric properties of quasi-monocrystal ZnO film.