Fabrication of a UV photodetector based on ZnO/CuO core-shell heterojunction nanorod arrays with Ag interdigitated electrodes

Abstract

ZnO nanorods, characterized by their non-toxicity, wide bandgap, and large exciton binding energy, represent ideal materials for UV photodetectors. However, intrinsic ZnO nanorods exhibit limitations including high recombination rates of photogenerated electron-hole pairs, low photogenerated carrier transport efficiency, and photocorrosion issues. To address these challenges, this study fabricated ZnO/CuO core-shell heterojunctions through a combined low-temperature hydrothermal synthesis and liquid-phase deposition integrated with thermal annealing. Specifically, a CuO shell layer was deposited onto the surface of ZnO nanorods. The heterojunctions were systematically characterized for morphology, elemental composition, and crystalline structure. Subsequently, UV photodetector was fabricated by sputtering Ag interdigital electrodes onto the ZnO/CuO core-shell heterojunctions, followed by comprehensive evaluation of their optoelectronic performance. The results demonstrate that the ZnO/CuO core-shell heterojunctions exhibit enhanced absorption within the UV spectral range, achieving a photocurrent of 41.7 μA—a 1.6-fold enhancement compared to ZnO nanorods—with response and recovery times of 21 s and 13 s, respectively. The ZnO/CuO core-shell heterojunctions demonstrate significant potential for effectively suppressing the recombination probability of photogenerated carriers within the material system, thereby enhancing both charge carrier transport efficiency and photoelectric conversion performance. This distinctive architecture exhibits promising application prospects in photodetection technologies, particularly for developing high-performance optoelectronic devices.