Ordered GaN Nanorod Arrays for Self-Powered Photoelectrochemical Ultraviolet Photodetectors

Self-powered ultraviolet (UV) photodetectors have great application prospects in the fields of UV astronomy, environmental monitoring, and space communication. In particular, the emerging photoelectrochemical photodetectors (PEC PDs) without external bias, high sensitivity, and environmental sensitivity have attracted extensive attention. Herein, self-powered PEC PDs were designed and constructed by using highly ordered GaN nanorod arrays (NRAs) as photoelectrodes. Without external bias, PEC PDs with NRA structures exhibit a high peak responsivity of 6.04 mA/W and a detectivity of 5.14 × 1010 Jones, which are 12 and 5.1 times higher, respectively, than those of the planar device. The large solid–liquid interface of the nanorod structure will lead to an improved built-in electrical field to promote carrier collection and rapid directional transmission, which can enhance the generation and separation of photogenerated carriers. Moreover, an optimized nanoarray will increase the UV detection effect significantly, which provides instruction for the design and fabrication of high-performance self-powered PEC PDs in the future.