A fast-response and transparent solution–processed ultraviolet photodetector based on ZnO quantum–sized nanoparticles

Abstract

Solution-processed ultraviolet (UV) photodetectors with high performance have great potential in many practical applications. In this paper, quantum-sized zinc oxide (ZnO) nanoparticles (~ 5.5 nm) were synthesized by a simple and low-cost chemical reflux method. The crystalline structure, morphologies, and optical properties of ZnO nanoparticles were investigated in detail. The results showed that the as-synthesized ZnO nanoparticles were wurtzite-structured (hexagonal) ZnO and had specific surface area as high as 68.3 m2/g, the ZnO nanoparticulate thin films had a strong absorption in UV region and optical bandgap of 3.28 eV. Furthermore, an UV photodetector was fabricated using the as-prepared ZnO nanoparticles, the device revealed stable, rapid and repeatable photoresponse towards 365 nm UV light, the sensitivity (S), responsivity (R), rise time (Tr), and decay time (Td) of the photodetector was 11.4 at − 0.25 V, 22.1 A/W at 3 V, 1.8 s and 47.2 s, respectively. In addition, the photoresponsive mechanism of this UV photodetector was systematically illuminated according to the adsorption-photodesorption theory of oxygen in ZnO nanoparticles.