Open AccessImmersed finger-type indium tin oxide ohmic contacts on p-GaN photoelectrodes for photoelectrochemical hydrogen generation
Author(s) -
Shu Yen Liu,
Jinn-Kong Sheu,
M. L. Lee,
Yu Chuan Lin,
Shang Ju Tu,
Fenglan Huang,
Wei–Chih Lai
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.00a190
Subject(s) - ohmic contact , materials science , indium tin oxide , photocurrent , optoelectronics , indium , hydrogen , hydrogen production , water splitting , photoelectrochemical cell , oxide , photoelectrochemistry , electrode , layer (electronics) , nanotechnology , electrochemistry , photocatalysis , electrolyte , chemistry , metallurgy , biochemistry , organic chemistry , catalysis
In this study, we demonstrated photoelectrochemical (PEC) hydrogen generation using p-GaN photoelectrodes associated with immersed finger-type indium tin oxide (IF-ITO) ohmic contacts. The IF-ITO/p-GaN photoelectrode scheme exhibits higher photocurrent and gas generation rate compared with p-GaN photoelectrodes without IF-ITO ohmic contacts. In addition, the critical external bias for detectable hydrogen generation can be effectively reduced by the use of IF-ITO ohmic contacts. This finding can be attributed to the greatly uniform distribution of the IF-ITO/p-GaN photoelectrode applied fields over the whole working area. As a result, the collection efficiency of photo-generated holes by electrode contacts is higher than that of p-GaN photoelectrodes without IF-ITO contacts. Microscopy revealed a tiny change on the p-GaN surfaces before and after hydrogen generation. In contrast, photoelectrodes composed of n-GaN have a short lifetime due to n-GaN corrosion during hydrogen generation. Findings of this study indicate that the ITO finger contacts on p-GaN layer is a potential candidate as photoelectrodes for PEC hydrogen generation.