Field-emission properties of carbon nanotubes grown on a submicron-sized tungsten tip in terms of various buffer layers

Abstract

Submicron-sized conical tungsten (W) field emitters based on carbon nanotubes (CNTs) are fabricated with the configuration of CNTs/catalyst/buffer/W tip by using various buffer layers such as TiN, Al, Al/TiN, and Al/Ni/TiN. This study focuses on elucidating how the buffer layers affect the structural properties of CNTs and the electron-emission characteristics of CNT emitters. Field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) are used to study the nanostructures, surface morphologies, chemical bonds of the catalysts, and grown CNTs. Further, the crystalline structure of CNTs is characterized by Raman spectroscopy. Furthermore, the measurement of field-emission characteristics of all the fabricated field emitters shows that the emitter that employs the Al/Ni/TiN stacked buffer exhibits excellent performances, e.g., a maximum emission current of 202 mu A, threshold field of 2.08 V/mu m, and long-term (up to 24 h) stability of the emission current. (C) 2008 Elsevier B.V. All rights reserved.