Effect of Crystallinity on the Field Emission Characteristics of Carbon Nanotube Grown on W-Co Bimetallic Catalyst.

ABSTRACT

Carbon nanotube (CNT) is an excellent field emission material. However, uniformity and stability are the key issues hampering its device application. In this work, a bimetallic W-Co alloy was adopted as the catalyst of CNT in chemical vapor deposition process. The high melting point and stable crystal structure of W-Co helps to increase the grown CNT diameter uniformity and homogeneous crystal structure. High-crystallinity CNTs were grown on the W-Co bimetallic catalyst. Its field emission characteristics demonstrated a low turn-on field, high current density, stable current stability, and uniform emission distribution. The Fowler-Nordheim (FN) and Seppen-Katamuki (SK) analyses revealed that the CNT grown on the W-Co catalyst has a relatively low work function and high field enhancement factor. The high crystallinity and homogeneous crystal structure of CNT also reduce the body resistance and increase the emission current stability and maximum current. The result provides a way to synthesis a high-quality CNT field emitter, which will accelerate the development of cold cathode vacuum electronic device application.