Schottky nanocontacts on ZnO nanorod arrays

Abstract

We report on fabrication and electrical characteristics of ZnO nanorod Schottky diode arrays. High quality ZnO nanorods were grown for the fabrication of the Schottky diodes using noncatalytic metalorganic vapor phase epitaxy and Au was evaporated on the tips of the vertically well-aligned ZnO nanorods. $\mathrm{I–V}$ characteristics of both bare ZnO and Au/ZnO heterostructure nanorod arrays were measured using current-sensing atomic force microscopy. Although both nanorods exhibited nonlinear and asymmetric $\mathrm{I–V}$ characteristic curves, Au/ZnO heterostructure nanorods demonstrated much improved electrical characteristics: the reverse-bias breakdown voltage was improved from $\text{−3}$ to $\text{−8\hspace{0.17em}}\mathrm{V}$ by capping a Au layer on the nanorod tips. The origin of the enhanced electrical characteristics for the heterostructure nanorods is suggested.