Open AccessHydrogen gas generation using n-GaN photoelectrodes with immersed Indium Tin Oxide ohmic contacts
Author(s) -
Shu Yen Liu,
Yu Chuan Lin,
Jhao Cheng Ye,
Shang Ju Tu,
Fenglan Huang,
M. L. Lee,
Wei–Chih Lai,
Jinn-Kong Sheu
Publication year - 2011
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.19.0a1196
Subject(s) - ohmic contact , materials science , indium tin oxide , photocurrent , optoelectronics , electrode , indium , tin , layer (electronics) , electrolyte , hydrogen , nanotechnology , metallurgy , chemistry , organic chemistry
An n-GaN photoelectrochemical (PEC) cell with immersed finger-type indium tin oxide (ITO) ohmic contacts was demonstrated in the present study to enhance the hydrogen generation rate. The finger-type ITO ohmic contacts were covered with SiO₂ layers to prevent the PEC cell from generating leakage current. Using a 1M NaCl electrolyte and external biases, the typical photocurrent density and gas generation rate of the n-GaN working electrodes with ITO finger contacts were found to be higher than those with Cr/Au finger contacts. The enhancement in photocurrent density or gas generation rate can be attributed to the transparent ITO contacts which allowed the introduction of relatively more photons into the GaN layer. No significant corrosion was observed in the ITO layer after the PEC process compared with the Cr/Au finger contacts which were significantly peeled from the GaN layer. These results indicate that the use of n-GaN working electrodes with finger-type ITO ohmic contacts is a promising approach for PEC cells.