High-Responsivity Self-Powered Photoelectrochemical UV Photodetector Based on Integrated Self-Supporting SiC/ZnS Heterojunction Nanowire Arrays

Abstract

In the realm of photodetector (PD) technology, photoelectrochemical (PEC) PDs have garnered attention owing to their inherent advantages. Advances in this field depend on functional nanostructured materials, which are pivotal in improving the separation and transport of photogenerated electron–hole pairs to improve device efficiency. Herein, a highly photosensitive PEC UV PD is built using integrated self-supporting SiC/ZnS heterojunction nanowire array photoelectrodes through anodization and chemical deposition. Compared with the original SiC nanoarrays, the optimized SiC/ZnS-25 nanoarrays exhibit high photocurrent density (Dph, 809.2 µA cm−2), rapid rise/decay times (τr/τd, 4/21 ms), high responsivity (Rλ, 1.226 A W−1), remarkable detectivity (D*, 2.517 × 1011 Jones), and large external quantum efficiency (EQE, 40.57%) under 375 nm UV light with a bias voltage of 0.6 V. Furthermore, SiC/ZnS-25 delivers excellent self-powered performance, with Rλ, D*, and EQE reaching 0.91 A W−1, 1.69 × 1011 Jones, and 30.24%, respectively. In addition, the device exhibits excellent long-term operation and aging stability under a bias voltage of 0.6 V and under self-powered conditions. The excellent photodetection behaviors of the SiC/ZnS PEC PD are mainly ascribed to the synergistic effect of the novel well-aligned nanowire geometry, heterojunction with ZnS nanofilms of optimal thickness, and integrated self-supporting configuration of the photoelectrode.