Plasmonic Ag nanoparticle-enhanced NiO/ZnO heterojunction for high-performance self-powered UV–visible broadband photodetection

Self-powered ultraviolet (UV) photodetectors (PDs) have garnered significant attention due to their exceptional performance. Implementing effective light-trapping strategies is crucial for enhancing the performance of PDs and photovoltaic cells. One approach is the incorporation of plasmonic nanoparticles (NPs) within the device structure, which can significantly improve light absorption and overall device efficiency. Here, we successfully fabricated self-powered UV-visible broadband PDs based on ITO/NiO/ZnO and ITO/NiO/Ag NPs/ZnO heterojunction devices. The ITO/NiO/ZnO device has a peak responsivity of 2.5 A/W at 365 nm at 2 V reverse bias, which rises to 5.6 A/W when introducing Ag NPs between NiO and ZnO layers. Similarly, the specific detectivity rises from 4.3 × 1011 to 5.0 × 1011 Jones*, and the external quantum efficiency) improves from 879% to 1887%. At a reverse bias voltage of 0.5 V, the device with Ag NPs demonstrates a 19-fold increase in responsivity compared to the device without NPs, peaking at 530 nm. Furthermore, under self-bias conditions, the Ag NP-integrated device had a maximum responsivity of 1.79 mA/W at 530 nm, which is roughly 38 times higher than the 0.047 mA/W measured for the device without NPs. Additionally, the rise and fall times for the ITO/NiO/ZnO device, initially 1.28 and 0.81 s, improved to 0.99 and 0.57 s with the incorporation of Ag NPs, demonstrating enhanced response speed. These findings show that Ag NPs greatly improve the photodetection efficiency of NiO/ZnO heterostructures, indicating a strong potential for high-performance UV-visible broadband PDs in both reversed and zero-biasing configurations.