Growth and electron field-emission of single-crystalline ZnO nanowires

ZnO nanowires with high density are grown over zinc foil by thermal evaporation process at relatively low temperature. Electron microscopy studies confirmed that the as-grown nanowires are of single crystal hexagonal wurtzite structure, growing preferentially in the c-axis direction. The Raman spectrum of the ZnO nanowires shows an optical-phonon E-2 mode at 440 cm(-1) confirming good crystallinity for the grown nanowires. The field emission measurement indicated that ZnO nanowires have a turn-on field of 9.1 V/mu m at current density of 0.001 mu A/cm(2). (C) 2012 Elsevier B.V. All rights reserved.