Study on the enhanced performance of visible photodetector based on hybrid structure between reduced graphene oxide and modified ZnO nanorods

Abstract

Photodetectors based on Zinc oxide (ZnO) have been widely researched due to their significant advantages such as simple fabrication process, high stability, etc. However, the application range of these devices is still limited in the ultraviolet (UV) region, and their reported performance is not as high as desired. Therefore, this study introduces a simple fabrication process of a photodetector based on the hybrid structure of reduced graphene oxides and zinc oxide nanorods (ZnO NRs) decorated silver nanoparticles (Ag NPs). In this RGO/ZnO–Ag structure, the ZnO–Ag serves as a light absorption complex to generate charge carriers through the surface plasmon resonance (SPR) effect and RGO acts as a transport layer driving the photocarriers for the enhancement of photocurrent. The results show that by decorating Ag NPs onto ZnO NRs, the absorption range of ZnO was widened toward longer wavelengths (the optical band gap reduced from 3.2 eV to 3.12 eV). Besides, by incorporating an RGO transport layer, not only the response and recovery time of the ZnO–Ag device were shortened but also its performance parameters were significantly enhanced (the responsivity increased from 5.32 to 6.58 A W−1 and the photoconductive gain rose from 16.92 to 20.70). This reveals the promise of our innovation in hybrid structure of transport layer and modified ZnO for practical photodetector applications.