This article reports the electrical characteristics of pristine, polycrystalline and single crystalline nickel (Ni) layer capped zinc oxide (ZnO) nanowires. Core/shell ZnO/Ni nanostructures were developed using chemical vapor deposition and e-beam evaporation, and the structures were annealed at different temperatures. Field effect transistor (FET) devices were fabricated using photolithography and investigated their characteristics at room temperature. All FET devices exhibited depletion-mode characteristics with n-type conductivity. However, single-crystalline Ni shelled ZnO nanowires based FET devices showed a high on/off ratio and transconductance, as compared to other devices. The overall measurements show that though the ZnO nanowires capped with Ni layer, their electrical properties remain same as pristine ZnO nanowires. (C) 2017 Elsevier B.V. All rights reserved.