Influence of the contact interface on the electrical characteristics of a ZnO microwire with silver paste electrodes

We investigate the influence of the contact interface on the electrical properties of a ZnO microwire (MW) with silver (Ag) paste electrodes. The ZnO MW devices that are produced by dropping Ag paste on the ZnO MW surface followed by a curing step at an elevated temperature exhibit linear current-voltage characteristics, whereas the devices with Ag paste electrodes dropped upon a heated ZnO MW exhibit a non-linear electrical behavior. The results of electron microscopy and cathodoluminescence show the effect of the contact interface properties, such as interfacial defects and/or charge trap sites, between the ZnO MW and Ag paste electrodes. An energy band model is suggested to explain the charge transport mechanism for different types of Ag contacts on the ZnO MW. (C) 2016 Elsevier B.V. All rights reserved.