Light Trapping Regulation of Tilted InGaN Nanowire Arrays to Enhance Photoelectrochemical Performance

The construction of efficient light-harvesting/conversion materials is the key to photoelectrochemical (PEC) water splitting. It should not be overlooked that the precise construction of materials and electrode structures plays a crucial role in the performance of its photoelectricity. Traditional structures (including dense film, pyramid and vertical nanowire (NW)) usually result in nonnegligible light loss, hierarchical antireflection structures of NW arrays on nonplanar substrates are efficient approaches to maximize the light absorption for PEC water splitting. Here, we constructed InGaN NW arrays with adjustable tilt angle on nonplanar substrates by plasma assisted-molecular beam epitaxy, and find the photoelectrical properties are closely related to their tilt angle and NW spacing. As a function of tilt, the photocurrent is dependent on the inclination, showing a trend of first increasing and then decreasing. NW arrays with more separated NWs exhibit larger photocurrent enhancement at larger tilt angle up to 116% at 81.9°. This study compiles the effects of various NW array morphologies on the PEC performance under varied light incidence angle, provides reference for the design of vertical NW arrays on nonplanar substrates acting as hierarchical antireflection structures for efficient light absorption on PEC and photoelectric applications.