High-Performance Broadband Photo-Detection in Solution-Processed ZnO-ZnCr2O4 Nanowalls

We demonstrate high performance broadband UV-to-NIR detection, which is a critical issue associated with ZnO-based photodetectors. The as-synthesized ZnO-ZnCr 2 O 4 nanowalls were first time utilized for broadband, i.e., 250-850 nm photo-detection (both in front and back illumination configurations). The dark current was found to be as low as 0.12 nA. The device has shown peak sensitivity for the UV region ( \lambda _{\mathrm {ex}}= {350} nm) with the photo-sensitivity of \sim 1.28\times 10^{5} , photo-responsivity of 5.49 AW −1 , photo-detectivity of 1.91\times 10^{13} cmHz 1/2 W −1 , linear dynamic range of 82 dB, and external quantum efficiency of 1900%. In addition, the white light emission (CIE coordinates of 0.32 and 0.34) was also observed in the ZnO-ZnCr 2 O 4 nanowalls. This letter will open new directions in oxide semiconductors-based optoelectronic devices.