High-performance broadband photo-detection in solution-processed ZnO-ZnCr2O4 Nanowalls

Abstract

We demonstrate high performance broadband UV-to-NIR detection, which is a critical issue associated with ZnO-based photodetectors. The as-synthesized ZnO-ZnCr2O4 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 ( λex= 350 nm) with the photo-sensitivity of ~1.28× 105 , photo-responsivity of 5.49 AW-1, photo-detectivity of 1.91 × 1013 cmHz1/2W-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-ZnCr2O4 nanowalls. This letter will open new directions in oxide semiconductors-based optoelectronic devices. © 1980-2012 IEEE.