LENGTH EFFECT ON THE ELECTRONIC TRANSPORT PROPERTIES OF MG/ZNO NW/MG NANOSTRUCTURES STUDIED BY FIRST PRINCIPLES CALCULATION

摘要

First principles calculations were performed to study the electronic structures and transport properties of Mg/ZnO NW/Mg nanostructures and the length effect via the Siesta/Transiesta codes. It is found that when the length of the ZnO nanowires between the Mg electrodes is short, local density of states (LDOS) near the Fermi level distribute over the whole scattering region and good conductance, Ohmic contact were observed, due to charge redistribution at the interface of Mg and ZnO. When the length of ZnO nanowires becomes large, the LDOS near the Fermi level vanishes in the center of the ZnO nanowires, which result in rectifying I - V curves and Schottky contact. The length of the ZnO nanowire between the Mg electrodes plays an important role in the I - V characteristics of the Mg/ZnO/Mg nanostructures.