Field emission characteristics of a single free standing carbon nanotube with gate electrode

Abstract

In this paper, we have constructed and analyzed the field emission behavior of a single vertically aligned free standing carbon nanotube (CNT) with a gate electrode in order to verify the feasibility of using a single CNT as the low-voltage field emission electron source. The single vertically aligned CNT with gate electrode was fabricated by combining optical lithography, electron beam lithography (EBL) and inductively coupled plasma chemical vapor deposition (ICP-CVD) processes. A self-aligned process with a single mask was utilized to define the gated structure and the nano-size catalyst for CNT growth. A single vertically aligned CNT was then grown within the gate hole by ICP-CVD. The length-to-diameter ratio of CNT could be varied by adjusting the e-beam exposure time, and the CNT height was controlled to equal to the gate-to-cathode spacing (800) nm in one gated device and less than the spacing (530 nm) in another device. The field emission characteristics of the integrated gate electrode devices were then measured under a scanning electron microscopy (SEM) with a three-axis nano-positioning device. The turn-on field of the gated devices with 800 and 530 nm height CNT were 2.77 and 3.57 V/μm, respectively, with applying − 10 V gate voltage, and 0 V anode voltage.