Morphology-driven UV photodetection in self-powered Pt/ZnO Schottky devices

Emerging nanostructured materials have opened new frontiers in the design of high-performance optoelectronic devices, particularly for self-powered photodetection applications. Here, we present the novel self-powered UV photodetection capabilities of Pt/ZnO Schottky barrier devices that fabricated with two distinct ZnO morphologies: dendrite-like nanoclusters (DNCs) and nano- micro-cluster arrays (NMCAs). Both architectures demonstrate robust self-powered UV photodetection performance, albeit with significant differences in their optoelectronic behavior. The DNC-based UV photodetector (Pt/ZnO_DNCs), characterized by weak inter-nanoparticle connections and smaller structural dimensions, exhibits reduced photocurrent, higher noise levels, and non-linear photoresponse dynamics under elevated UV illumination. Conversely, the NMCA-based devices (Pt/ZnO_NMCAs), formed through capillary-driven self-assembly of DNCs using a single ethanol droplet, achieve a dramatic enhancement in performance, with a nearly thousand-fold increase in photocurrent, alongside excellent repeatability and long-term stability. Furthermore, the Pt/ZnO_NMCAs exhibit a 3.5-fold improvement in response time, with a rise time of 9.6 s compared to 51.9 s for the DNC-based variant under a UV light intensity of 2.5 mW·cm^-² in self-powered mode. These findings underscore the significant potential of NMCA-structured ZnO nanomaterials as high-performance candidates for photoconductive devices, advancing the development of self-powered optoelectronic technologies.