Enhanced InGaN/GaN photoelectrodes for visible‐light‐driven hydrogen generation by surface roughening

Abstract

Phone: þ86 025 83685367, Fax:þ86 025 83685356 III-Nitride semiconductor materials are considered as promising candidates for photoelectrodes (PEs) due to their adjustable direct band gap covering a very broad spectral range. In this study, InGaN/GaN based p-i-n photoelectrodes have been fabricated and nano-sized surface roughening process has been applied. The photocurrent gets 2.5 times enhancement and the incident photon conversion efficiency (IPCE) is improved to be $30% at the wavelength of 400 nm. In addition, the turn-on voltages of InGaN/GaN-based PEs have been effectively reduced from þ0.8 V down to about À0.4 V (vs. reversible hydrogen potential, RHE). Such improvements are mainly attributed to reduced dislocation density, increased surface area, and optimized build-in electrical field. These findings give innovative insight to improve photoelectrochemical devices for hydrogen generation.