Properties of gated single free-standing carbon nanotube with multiple growth sequence

Abstract

In this paper, we discuss an approach to fabricating a carbon nanotubes (CNTs) gate electrode structure for cold cathode emitter applications. The field emission behavior of the structure was studied by using single vertically aligned free-standing CNTs of various lengths and gate electrodes of various sizes to determine the optimal emission structure. A single CNT electrode source with a gate electrode was fabricated by combining optical lithography, electron-beam lithography (EBL), and inductively coupled plasma chemical vapor deposition (ICP-CVD). A single mask was adopted to define the gated structure and nano sized catalyst for CNT growth. A vertically aligned CNT was then grown within the gate hole by ICP-CVD. The CNT height inside the gate could be lengthened by multiple growth processes without affecting the field emission capability. The best turn-on fields, defined as the field required to generate an emission current of 1 nA, were approximately 1.66 and 1.38 V/mu m, respectively. The turn-on field emission current saturated when the CNT length was about the same as the gate height.