An approach to control the tip shapes and properties of ZnO nanorods

Abstract

High-density, well aligned, -oriented wurtzite ZnO nanorod arrays with significantly different tip shapes werecontrollably fabricated by evaporating zinc powders at temperatures varying from 450 to600 °C. It is found that the tip shape depends not only on the substrate but also on the substratedirection relative to the auxiliary gas flow, and the radius of curvature at these tips can beless than 2 nm. These nanorods exhibit good rectification characteristics in conductiveatomic force microscopy (CAFM) measurements; the current rectification can be as large as∼103 at 1 V. The conductance of these ‘nanotips’ can be tuned readily by simple air-annealing.