UV photodetector with ZnO nanoflowers as an active layer and a network of Ag nanowires as transparent electrodes

This study demonstrates a novel, simple, and process-compatible approach to fabricate UV photodetectors (PDs) based on an asymmetric metal-semiconductor-metal (MSM) structure, with ZnO nanoflowers (NFs) as the active layer. A network of silver nanowires (AgNWs) is used as a low-resistivity transparent electrode. The MSM UV PDs based on AgNWs/ZnONFs/AgNWs showed low dark current of the order of nA and a photo-to-dark current ratio of two orders of magnitude at + 3 V and more than 3 orders of magnitude at -3 V of asymmetric MSM UV PDs based on AgNWs/ZnONFs/AgNWs with a source (S) and drain (D) channel width of 570 mu m. The UV sensitivity and responsivity at 0 V of the device with the wider S/D channel was as high as 6.34 x 10(4) and 9.4 x 10(-3) AW(-1), respectively. The findings suggest that UV PDs based on ZnONFs with asymmetric Ag network electrodes with ZnONFs hold promise for use in future optoelectronic devices.