High‐Responsivity SiC/TiO 2 Photoelectrochemical Ultraviolet Photodetector: Heterojunctions with Fast Response Times and Excellent pH Tolerance

Abstract The precise control of the surface properties of low‐dimensional nanostructures is a prerequisite for preserving the intrinsic material quality and manipulating the carrier transport behavior to enhance optoelectronic device performance. Herein, a high‐responsivity photoelectrochemical (PEC) ultraviolet (UV) photodetector (PD) based on SiC/TiO 2 heterojunction nanowires is developed. The surface of SiC nanowires is decorated with high‐quality TiO 2 nanoparticles through a simple hydrothermal process, and a type‐II heterojunction is established. The fabricated SiC/TiO 2 heterojunction nanowire PEC PD exhibited excellent photoresponsivity with high responsivity (50.97 mA W −1 ), detectivity (1.07 × 10 12 Jones), and external quantum efficiency (16.85%) under 375 nm ultraviolet illumination. Response and decay times are as low as 0.3 and 0.1 ms, respectively—these values are within the state‐of‐the‐art range for semiconductor nanostructure–based PEC PDs reported thus far. The device also exhibits excellent photoresponsivity and long‐term stability under different light intensities, even in harsh universal‐pH liquid environments, including acidic, neutral, and alkaline solutions with different concentrations. The elevated photodetection performance of the device is primarily attributed to the effective synergistic effect of the formation of a type‐II charge transfer pathway in the SiC/TiO 2 heterostructure, the optimal load capacity of TiO 2 nanoparticles, and the excellent inherent corrosion resistance of SiC and TiO 2 .