I-V Characteristics of Metal-Oxide-ZnSe Nanowire Structure

The electron transport of metal-insulator-semiconductor nanowire (MIS) structure consisting of the Al electrode covered by a thin alumina oxide layer and a single ZnSe nanowire was studied experimentally. The I-V measurement of an individual ZnSe nanowire contacted to Au and the alumina oxide covered Al electrodes, which resulted in metal-semiconductor (MS) and MIS structures at Au/ZnSe and Al/AlOx/ZnSe interfaces, respectively, has been carried out by in situ transmission electron microscopy (TEM). These measured I-V curves have the typical nonlinear feature coincident with the Schottky contact barriers at the interfaces between the semiconductor and metal electrodes. There is no current recorded between 3.8 V, and the threshold voltage range was therefore examined. This high threshold voltage obviously resulted from the thin alumina oxide layer at the surface of the Al electrode, which acts as an insulator and, consequently, results in high contact barrier. The asymmetrical characteristics resulting from slow increase in current under the reverse bias can be explained by part of the electrons in Al electrode tunneling the alumina oxide at the energy levels corresponding to the position of the bandgap of the ZnSe semiconductor.