Promising field electron emission performance of vertically aligned one dimensional (1D) brookite (β) TiO2 nanorods

Abstract

We evidence field-electron emission (FE) studies on the large-area array of one-dimensional (1D) brookite (β) TiO₂ nanorods. The pure 1D β-TiO₂ nanorods of 10 nm width and 760 nm long were synthesized on Si substrate utilizing hot-filament metal vapor deposition technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis evidenced the β-TiO₂ nanorods to be composed of orthorhombic crystals in brookite (β) phase. X-ray photoemission spectroscopy (XPS) revealed the formation of pure stoichiometric (i.e. 1 : 1.98) 1D TiO₂ nanorods. The values of turn-on field, required to draw current density of 10 μA cm⁻², was observed 3.9 V μm⁻¹ for pristine 1D β-TiO₂ nanorods emitters, which were found significantly lower than doped/undoped 1D TiO₂ nanostructures (i.e. nanotubes, nanowires, nanorods) based field emitters. The enhanced FE behavior of the TiO₂/Si emitter can be attributed to modulation of electronic properties due to the high aspect ratio of vertically aligned TiO₂ nanorods. Furthermore, the orthodox emission situation of pristine TiO₂/Si emitters exhibit good emission stability and reveal their potentials as promising FE material.