LAUSR

Abstract We study Ⅲ-nitride nanowire (NW) anti-reflection structures employed as photoelectrocatalyst for solar water splitting. We found that 1D vertical InGaN NW arrays tilted by 73° exhibit maximized photocurrent. Therefore, we grow 3D InGaN NW arrays on the facets of oblique pyramid-textured Si (311) (OPSi/InGaN) by plasma-assisted molecular beam epitaxy, exhibiting facets tilted by 73°. In addition, using finite difference time domain simulations we find the crucial impact of the asymmetry of the oblique pyramid InGaN NW arrays on the light trapping. Compared with InGaN NWs grown on a planar Si substrate (Si/InGaN), the OPSi/InGaN photoanode exhibits ~500% enhancement of the photocurrent due to various light trapping effects attributed to: 1D vertical NW arrays, their tilt, 3D arrangement and asymmetry. Decorated with NiOOH co-catalyst, the OPSi/InGaN photoanode exhibits photocurrent densities in the mA cm−2 range. The present research provides a rational design for the fabrication of nanostructured photoelectrocatalyst with enhanced light absorption.