Shape-dependent electrical property of solution synthesized ZnO nanorods

Abstract

Synthesis of linked-ZnO nanorods by the aqueous solution method and its electrical characterization by constructing metal-ZnO nanorod–metal devices are reported. Aluminum and gold metals were used to produce electrical contacts to the ZnO nanorods using the lithography and lift-off processes. Current–voltage (I–V) characteristics of the aligned ZnO nanorod devices were analyzed, and they showed shape-dependent electrical property for both aluminum and gold contacts. Linked-ZnO nanorods of dissimilar ends have been found to show a nonlinear and asymmetrical I–V plot, showing rectifying diode-like behavior with the rectification ratio 103 at a bias of 2 V. The formation of Schottky diodes is suggested due to the asymmetric contacts resistance of metal-ZnO NR-metal devices. Space-charge-limited current conduction is found to influence the charge conduction in the nanorod under room-ambient condition. Photoresponse of the ZnO rods under different illumination is also demonstrated. It revealed that the photo absorption eliminates the effect of surface adsorbates on the ZnO nanorods.