title: Immersed finger-type indium tin oxide ohmic contacts on p-GaN photoelectrodes for photoelectrochemical hydrogen generation.
abstract: 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.
authors.affiliation: Department of Photonics & Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan City 70101, Taiwan.
authors.forename: Shu-Yen
authors.initials: SY
authors.lastname: Liu
authors.forename: J K
authors.initials: JK
authors.lastname: Sheu
authors.forename: M L
authors.initials: ML
authors.lastname: Lee
authors.forename: Yu-Chuan
authors.initials: YC
authors.lastname: Lin
authors.forename: S J
authors.initials: SJ
authors.lastname: Tu
authors.forename: F W
authors.initials: FW
authors.lastname: Huang
authors.forename: W C
authors.initials: WC
authors.lastname: Lai