Growth of the Serrated GaN Nanowire and its Photoelectrochemical Application

Abstract Introducing polyhedral facets into a high surface-to-volume nanowire structure (i.e., serrate-shaped or screw thread-like nanowire) is an effective way for boosting the photoelectrochemical (PEC) activity. However, fabricating such nanowires with serrated surfaces remains a challenge because it usually involves many complex processes, thus limiting mass activity. Here, we demonstrate a strategy for natural growth of the serrated GaN nanowires on a LiGaO2 substrate by using an Au catalyst-assisted vapor-liquid-solid method. The specific GaN nanowire grew through an atypical growth mechanism due to the partial deformation of the Au catalyst. The serrated GaN nanowire exhibited a higher photocurrent density of 0.391 mA/cm2 at 1.23 V versus RHE, which was approximately 2.3 times that of the GaN film (0.157 mA/cm2). The high stability of the photoresponse and photocurrent of the serrated nanowire was verified in a wide angle-dependent illumination. This work opens a new way for strengthening the PEC performance of the GaN-based photoanodes by introducing serrate-shaped surfaces on the GaN nanowires.