Abstract
Device characteristics of thermal CVD grown carbon nanotubes (CNTs) field emitters in diode and triode configurations are reported. The CNT cathode configured as field emission diode exhibited a low turn-on field of ∼3.0 V/μm, high emission current of ∼35 mA at ∼5.0 V/μm, and excellent current stability. Large signal model (dc) and small signal model (ac) of the field emission diode were also investigated. The CNT triode was achieved by integrating a TEM grid (transmission electron microscope specimen holder) as the gate electrode to the CNT cathode, with no further micro-fabrication processes needed. The CNT triode displayed gate-controlled current modulation behavior with distinct cutoff, linear and saturation regions. The triode has a gate turn-on field of ∼5.4 V/μm despite a large cathode-gate spacing of ∼120 μm. The field emission data established the basic transistor characteristics of CNT emitters in a triode amplifier configuration with good gain. The detailed dc characteristics and transistor ac parameters such as transconductance, amplification factor, and anode resistance for the CNT triode were investigated and modeled. © 2005 Elsevier B.V. All rights reserved.