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Proceedings Paper

Surface modification of a-SiC photoelectrodes for photocurrent enhancement
Author(s): Ilvydas Matulionis; Jian Hu; Feng Zhu; Josh Gallon; Nicolas Gaillard; Todd Deutsch; Eric Miller; Arun Madan
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Paper Abstract

Photoelectrochemical (PEC) water dissociation into hydrogen and oxygen at a semiconductor-liquid interface offers an environmentally benign approach to hydrogen production. We have developed an integrated PEC device using hydrogenated amorphous silicon carbide (a-SiC or a-SiC:H) material as photoelectrode in conjunction with an amorphous silicon (a-Si) tandem photovoltaic device. Such a "hybrid PV/a-SiC" PEC cell produces photocurrent of about 1.3 mA/cm2 in a short-circuit configuration and is durable in a pH2 electrolyte. On the other hand, the aforementioned structure finished with ITO contacts and measured as a solid-state device features a current density of 5 mA/cm2, indicating a potential solar-to-hydrogen (STH) conversion efficiency of about 6% in the hybrid PV/a-SiC PEC cell. The much lower photocurrent measured in the hybrid PEC cell suggests that there exists an interfacial barrier between the a-SiC and electrolyte, which hinders the photocurrent extraction. In order to mitigate against the interfacial barrier and hence improve the photo-generated charge carrier transport through the a-SiC/electrolyte interface, we have explored several surface modification techniques, namely the use of metallic nano-particles (such as platinum or palladium) and the growth of an additional thin layer (a-SiNx, carbon-rich a-SiC, a-SiF, etc.) on the top of a-SiC by PECVD. In the latter case, it is observed that the addition of a thin PECVD-fabricated layer does not significantly improve the photocurrent, presumably due to a poor band alignment at the a-SiC/electrolyte interface. The use of lower work function nanoparticles like titanium has led to promising results in terms of photocurrent enhancement and an a nodic shift in the onset potential.

Paper Details

Date Published: 24 August 2010
PDF: 8 pages
Proc. SPIE 7770, Solar Hydrogen and Nanotechnology V, 77700Z (24 August 2010); doi: 10.1117/12.860669
Show Author Affiliations
Ilvydas Matulionis, MVSystems, Inc. (United States)
Jian Hu, MVSystems, Inc. (United States)
Feng Zhu, MVSystems, Inc. (United States)
Josh Gallon, MVSystems, Inc. (United States)
Nicolas Gaillard, Univ. of Hawaii at Monoa (United States)
Todd Deutsch, National Renewable Energy Lab. (United States)
Eric Miller, Univ. of Hawaii at Monoa (United States)
Arun Madan, MVSystems, Inc. (United States)


Published in SPIE Proceedings Vol. 7770:
Solar Hydrogen and Nanotechnology V
Hicham Idriss; Heli Wang, Editor(s)

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