A crossbar-type high sensitivity ultraviolet photodetector array based on a one hole-one nanorod configuration via nanoimprint lithography

Abstract

Single crystalline vertical ZnO nanorods were grown in a one hole-one rod configuration using a hydrothermal method with a patterned polymer template generated by nanoimprint lithography, allowing precise control over the position and density of the ZnO nanorods. An 8 x 8 ZnO nanorod-based ultraviolet photodetector array is demonstrated, in which a well-confined number of ZnO nanorods are sandwiched between crossbar-type platinum and indium tin oxide electrodes (e. g. 16 nanorods in a 2 x 2 mu m(2) area). A high photocurrent/dark current ratio of 3 x 10(3) at a reverse bias of 1.5 V under UV illumination at room temperature, a responsivity of 4381.4 A W(-1) at 365 nm, and an ultraviolet-to-visible rejection ratio of 83 are obtained and maintained, irrespective of pixel size. A uniform photoresponse is achieved in each of the pixels, indicating the scalability with this technique for fabricating an integrated UV photodetector array circuit.