A voltage-modulated UV-VIS dual-band photodetector based on ZnO film/CuO nanowires

Dual-band photodetection plays a critical role in smart devices due to its ability to distinguish multi-wavelength signals. However, traditional dual-band photodetection relies on complex, bulky systems with multiple devices. It is highly desired to realize dual-band photodetection by one simple semiconductor device. Here, we present a voltage-modulated ultraviolet-visible (UV-VIS) dual-band photodetector based on a ZnO film/CuO nanowires. The device is composed of vertical CuO nanowires grown on a ZnO film, which is sandwiched in between top and bottom ITO transparent electrodes. With zero bias, the device can sense VIS light via the photovoltaic effect through a CuO/ZnO p–n junction. Under 10 V bias, the device can detect UV light by photoresistive behavior. The controllable dual-band detection is characterized, and the photodetection mechanism is analyzed by finite-element electric field simulations. Additionally, an image sensor with 5 × 5 pixel arrays is fabricated to demonstrate the controllable sensing capability for VIS or UV images. The research reported here may impact photodetection fields for controllable detecting dual band photo signals by a single semiconductor device.