Development of Dual-Band UV Photodetector Utilizing Nanostructured ZnO-ZnCr₂O₄

The use of multi-band photo-detection plays a crucial role in advancing several technologies, including light-wave communication, optical navigation technology, and environmental monitoring. In recent times, there has been a significant surge in the interest around the advancement of multiband ultraviolet (UV) photodetectors. Here, a high-performance dual-band UV photodetector based on ZnO-ZnCr2O4 nanostructures has been realized using a simple solution-process. The device has demonstrated dominant responses in UV-C (210 nm) and UV-A (350) regions. The associated photo-responsivity of 2.71 A/W and 1.91 A/W was calculated for UV-C and UV-A regions, respectively. The d-d transitions of Cr3+ in deep-UV region and band-to-band transitions of ZnO in UV-A region were found to be the prime reason for dual-band detection. This work paves the way for development of next-generation multi-band UV photodetector.