Electron field emission from single crystalline TiO2 nanowires prepared by thermal evaporation

Single crystalline TiO2 nanowires were grown over an Au-doped TiO2/silicon (Si) substrate at 850 °C by thermal evaporation using a radio frequency (RF) heater. The X-ray diffraction indexed reveals that the nanowires were in the TiO2 rutile phase. TiO2 nanowires were also examined using high-resolution transmission electron microscopy (HRTEM), indicating that the nanowires grew along the [1 1 0] axis as a single crystallinity. The field-emission properties of the single crystalline TiO2 nanowires were revealed by the Folwer-Nordheim (F-N) theory. A low turn-on field of ∼5.7 V/μm was obtained at a current density of 10 μA/cm2.