Fabrication of an InGaN/GaN nanotube-based photoanode using nano-imprint lithography and a secondary sputtering process for water splitting

Abstract

In this research, an InGaN/GaN nanotube-based photoanode has been fabricated by nano-imprint lithography and a secondary sputtering process. The involvement of a Au nano-ring mask allowed dry etching with a high aspect ratio on the InGaN/GaN substrate. After device fabrication, the measured optical spectrum showed this innovative structure provided low reflectance and high absorbance at the wavelength around the ultraviolet range. The photoelectrochemical properties indicated optimized tube height could efficiently enhance the water splitting efficiency by 15 times at 1.23 V versus RHE by increasing the surface reactive area and tuning the optical spectrum properties. The IPCE result also demonstrated a corresponding enhancement. (C) 2019 The Japan Society of Applied Physics