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GaN nano-pyramid arrays as an efficient photoelectrode for solar water splitting
Nanotechnology, Volume: 27, Issue: 45, Start page: 455401
Swansea University Author: Yaonan Hou
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DOI (Published version): 10.1088/0957-4484/27/45/455401
Abstract
A prototype photoelectrode has been fabricated using a GaN nano-pyramid array structure grown on a cost-effective Si (111) substrate, demonstrating a significant improvement in performance of solar-powered water splitting compared with any planar GaN photoelectrode. Such a nano-pyramid structure lea...
| Published in: | Nanotechnology |
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| ISSN: | 0957-4484 1361-6528 |
| Published: |
IOP Publishing
2016
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa65305 |
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| Abstract: |
A prototype photoelectrode has been fabricated using a GaN nano-pyramid array structure grown on a cost-effective Si (111) substrate, demonstrating a significant improvement in performance of solar-powered water splitting compared with any planar GaN photoelectrode. Such a nano-pyramid structure leads to enhanced optical absorption as a result of a multi-scattering process which can effectively produce a reduction in reflectance. A simulation based on a finite-difference time-domain approach indicates that the nano-pyramid architecture enables incident light to be concentrated within the nano-pyramids as a result of micro-cavity effects, further enhancing optical absorption. Furthermore, the shape of the nano-pyramid further facilitates the photo-generated carrier transportation by enhancing a hole-transfer efficiency. All these features as a result of the nano-pyramid configuration lead to a large photocurrent of 1 mA cm−2 under an illumination density of 200 mW cm−2, with a peak incident photon-to-current conversion efficiency of 46.5% at ∼365 nm, around the band edge emission wavelength of GaN. The results presented are expected to pave the way for the fabrication of GaN based photoelectrodes with a high energy conversion efficiency of solar powered water splitting. |
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| Keywords: |
photoelectrode, water splitting, hydrogen generation, GaN |
| College: |
Faculty of Science and Engineering |
| Funders: |
This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC). |
| Issue: |
45 |
| Start Page: |
455401 |