Improved UV photodetection by aligned Cu doped ZnO nanorods: the effect of Cu dopant concentration

Ultraviolet (UV) photodetectors are necessary in various areas such as civil fields and pollution monitoring. Herein, highly sensitive and fast responding aligned ZnO nanorods (NRs) based UV photodetectors through optimization of Cu dopant are reported. The effect of different concentrations of Cu elements on the microstructure and optical properties of the ZnO rods is studied by using appropriate characterization methods. Improved performance in terms of faster rise and decay times and sensitivity is achieved after Cu doping. The highest UV on/off ratio (1900), responsivity (28.6 mAW^− 1), and detectivity (7.9 × 10¹³ Jones) are obtained for the 1% Cu doped ZnO NRs, which are remarkable compared to most of the state-of-the-art photodetector devices. With further Cu content, both dark and photo currents decrease affecting the parameters of the photodetector, adversely. Faster reset time compared to pure ZnO NRs is attributed to the role of Cu dopant in the trapping and de-trapping of electrons.