Electrical characteristics and optoelectronic properties of metal--semiconductor--metal structure with zinc oxide nanowires across Au electrodes

This paper reports on a method of assembling semiconducting ZnO nanowires onto a pair of Au electrodes to construct a metal--semiconductor--metal (MSM) structure by dielectrophoresis and studying on its electrical characteristics by using current-voltage ($I-V$) measurements. An electronic model with two back to back Schottky diodes in series with a semiconductor of nanowires was established to study the electrical transport of the MSM structures. By fitting the measured $I-V$ characteristics using the proposed model, the parameters of the Schottky contacts and the resistance of nanowires could be acquired. The photoelectric properties of the MSM structures were also investigated by analysing the measurements of the electrical transports under various light intensities. The deduced results demonstrate that ZnO nanowires and their Schottky contacts with Au electrodes both contribute to photosensitivity and the MSM structures with ZnO nanowires are potentially applicable for photonic devices.