ZnO nanowire network/4H-SiC heterojunction for improved performance ultraviolet photodetector: The effect of different SiC doping concentrations on photoresponse properties

Zinc Oxide (ZnO) and Silicon Carbide (SiC) are highly promising semiconductors with their heterostructures offering pathways for the next generation of sensing and detecting optoelectronics technologies due to their wide bandgaps. Optoelectric properties of ZnO nanowire network and n-type single crystal 4H-SiC heterojunction ultraviolet (UV) photodetectors have been investigated and compared for two different SiC doping concentrations. The fabrication of a high-performance UV photodetector based on a ZnO/4H-SiC heterojunction with high SiC doping concentration of 10¹⁸/cm³ was achieved. Its optoelectronic performance was improved compared with either a ZnO UV photodetector or a ZnO/SiC heterojunction photodetector with low SiC doping concentration of 10¹⁶/cm³. Heterojunction constructing and energy band bending in the ZnO/SiC interface facilitates the spatial separation of the photogenerated electron-hole pairs and the efficient transport of photoinduced charge carriers, which enhances photocurrent and simultaneously enables a quick time response in the device. In addition, carriers tunneling occurs in the heterojunction interface of ZnO/n⁺SiC with narrower depletion region width. This study suggests an opportunity for large-area and high-performance nanostructured optoelectronic devices fabrication based on a simple synthesis process and energy band engineering.