Enhanced field emission from three-dimensional patterned carbon nanotube arrays grown on flexible carbon cloth

Abstract

Novel three-dimensional patterned carbon nanotube (CNT) arrays with excellent field emission (FE) performance have been fabricated on a flexible carbon cloth substrate by a facile and repeatable two-step process. Firstly, a discrete layer of ZnO nanowire arrays were synthesized on carbon cloth to act as a template for the patterned growth of CNTs. Then, CNTs were radially grown on the surface of the sparse ZnO nanowire arrays. The entire structure of the sample can still sustain its high flexibility after the high temperature growth process and can even be rolled up and twisted to a large degree without affecting the electric characteristics. For this novel three-dimensional patterned CNT array, a low turn-on field of 0.4 V μm⁻¹, a threshold field of 0.84 V μm⁻¹, a current density of 4.48 mA cm⁻² at a field of 1.34 V μm⁻¹, and a field enhancement factor as high as 4.9 × 10⁴ were ultimately obtained. Via calculation of the electrostatic field distribution, it was found that this giant enhancement of FE performance is due to the typical morphology which can significantly diminish the screen effect.