Self-powered ZnO/NiO dual-band photodetector based on surface plasmon enhancement

• Surface plasmon excites a localized strong electromagnetic field to increase the number of photogenerated carriers at the source and reduce the compound dominance problem caused by insufficient carriers. • The constructed ZnO/NiO p-n heterojunction combined with Pt plasmon modification realizes high-efficiency photoelectric response of the detector under zero bias, breaking the dependence on external power supply of traditional devices and expanding the application of self-powered detection scenarios. • Plasmon Localized strong electromagnetic fields synergize with high-energy hot electrons to shorten the device rise time and decay time, significantly improving the response delay problem caused by slow carrier transport. • Pt nanoparticles enable a wide range of absorption peak tuning, extending the detector to “ultraviolet-near ultraviolet” broadband spectral detection and breaking down application limitations. In order to solve the challenges of low photogenerated carrier separation efficiency and insufficient sensitivity for detection in self-powered photodetector (PD), a ZnO/NiO dual-band PD based on surface plasmon-enhanced Pt nanoparticles (NPs) modification was designed in this study. When the incident light frequency matches the oscillation frequency of free electrons on the surface of Pt NPs, a strong localized electromagnetic field is formed on the surface of the NPs, which can effectively enhance the light absorption intensity in the region of heterojunction and improve the capture ability of weak light signals. Without external power supply, the responsivity of the Pt-modified detector under UV irradiation could reach 9.29 mA/W, which was more than 78 % higher than that of the unmodified device, and the detection efficiency is increased to 3.11 × 10 12 Jones. The promotion of light absorption by plasmon was further verified by monitoring the electromagnetic field intensity distribution on the surface of Pt NPs and in the region of ZnO/NiO heterojunction by the finite difference time domain method. This study highlights the synergistic benefits of combining plasmonic nanostructures with heterojunction engineering, providing a promising strategy for the development of high-performance and miniaturized self-powered UV PD suitable for practical applications.