Nonlinear length dependent electrical resistance of a single crystal zinc oxide micro/nanobelt.

We have systematically investigated the intrinsic electrical property of a single crystal zinc oxide (ZnO) micro/nanobelt (MB/NB) using a conductive atomic force microscopy (AFM) technique. By mounting one end of the MB/NB on a flat nonconductive silicon substrate, a platform for performing electrical property characterization using conductive current AFM is established. The quantitative characterization of the electrical resistance of the MB/NBs was performed by acquiring I-V curves for the MB/NB in between the electrode and the conductive AFM tip. The resistance of the single crystalline ZnO MB/NB was measured to be exponentially dependent on the length of the MB/NB. A systematic model based on the anisotropic velocity of the carriers in the crystal planes has been proposed and fits the experimental measurement well. This research reveals that the electrical resistance shows a nonlinear length dependence in the semiconducting single crystal MB/NB, which is significantly different from the bulk counterpart. Understanding such a property could definitely improve the design and the performance of next generation electrical nanodevices.