Highly responsive ZnO nanorods array ultraviolet photodetectors modificated with reduced graphene oxide layer

In this paper, we demonstrate a new heterojunction ultraviolet (UV) photodetector in a superstrate configuration, i.e. glass/FTO/ZnO NRs/rGO/Au, constructed via the dip-coated method to form reduced graphene oxide (rGO) layer on the surface of ZnO nanorod arrays (NRs). The rGO compensates for surface oxygen vacancies by the oxygen-containing groups and improves the crystal properties of ZnO NRs after annealing. Furthermore, the carrier mobility and work function are effectively increased after Au doping. Under UV irradiation, the electron-hole pairs generated by ZnO NRs are separated with bias voltage, and the electrons and holes are collected via fluorine-doped tin dioxide (FTO) and rGO/Au, respectively. The rGO acts as a hole transport layer, which reduces the recombination of carriers and increases the current density, giving rise to a higher responsivity (67.48 A W-1 at -1.5 V bias) than pure ZnO NRs photodetectors.

Automated summary

This paper demonstrates a new heterojunction ultraviolet photodetector built in a superstrate configuration with optimized performance through dip-coating method. By introducing Au doping and rGO layer, the performance parameters of the photodetector are effectively improved.