Fabrication of GaN Nanowire Arrays via Electrodeless Photoelectrochemical Etching and its Application on UV Photodetectors

Gallium nitride (GaN), a widely used third‐generation semiconductor material, has garnered significant attention due to the extensive application of GaN‐based nanowires in optoelectronic detection fields. In this study, a mask‐free GaN nanowire arrays fabrication method based on electrodeless photoelectrochemical etching (ELPEC) is proposed. The morphological evolution mechanism is explained based on the electric field enhancement principle. The resulting GaN nanowires have a diameter ranging from 20 to 50 nm and a length of 1 to 3 µm. Through optimization of process parameters, a rapid etching rate of 110 nm min −1 is achieved. Based on the resulting nanowire arrays, a UV photodetector (UV PD) is developed, which demonstrates significantly enhanced performance. Under 365 nm illumination with a power density of 214.6 mW cm −2 and zero bias, the photodetector exhibits a net photocurrent 5.6 times greater than that of the unetched GaN device, with a responsivity of 10.53 mA W −1 and fast response. This study not only enriches the field of ELPEC etching but also offers new insights for the development of advanced GaN nanowire‐based optoelectronic devices.