Title: Characterization of n-GaN with Naturally Textured Surface for Photoelectrochemical Hydrogen Generation
Authors: Liu, Shu-Yen
Sheu, J. K.
Ye, Jhao-Cheng
Tu, S. J.
Hsu, Che-Kang
Lee, M. L.
Kuo, C. H.
Lai, W. C.
照明與能源光電研究所
Institute of Lighting and Energy Photonics
Issue Date: 2010
Abstract: To reduce light reflection and enlarge the effective reaction surface area at the n-GaN/electrolyte interface, n-GaN epitaxial layers with naturally textured surface are utilized. The layers are combined with Cr/Au ohmic contacts on n-GaN to form working electrodes that generate hydrogen by direct photoelectrolysis of water. Although the surface reflection on the naturally textured n-GaN samples is lower than that on n-GaN epitaxial layers with flat surface, our results reveal that the photocurrent (I(ph)) and gas generation rates (R(gas)) obtained from the naturally rough n-GaN samples are lower than those from the flat samples. The results can be attributed to the fact that the rough n-GaN surface caused by dense surface pits leads to significant recombination of photogenerated carriers with charged defects; this occurs before carriers reach the ohmic contacts, thereby resulting in lower I(ph) and R(gas). Related analyses have been performed and presented in this paper to initially explain the possible mechanism. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3499327] All rights reserved.
URI: http://hdl.handle.net/11536/6172
http://dx.doi.org/10.1149/1.3499327
ISSN: 0013-4651
DOI: 10.1149/1.3499327
Journal: JOURNAL OF THE ELECTROCHEMICAL SOCIETY
Volume: 157
Issue: 12
Begin Page: H1106
End Page: H1109
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