AVS 50th International Symposium
    Nanotubes Wednesday Sessions
       Session NT-WeP

Paper NT-WeP15
Fabrication and Characterization of Active Nanoscale Electronic Devices Based on Vertically Aligned Carbon Nanofibers (VACNF)

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: X. Yang, University of Tennessee
Authors: M.L. Simpson, Oak Ridge National Laboratory
X. Yang, University of Tennessee
M.A. Guillorn, Oak Ridge National Laboratory
D.W. Austin, University of Tennessee
V.I. Merkulov, Oak Ridge National Laboratory
A.V. Melechko, Oak Ridge National Laboratory
D.H. Lowndes, Oak Ridge National Laboratory
Correspondent: Click to Email
Arrays of deterministically grown VACNFs were synthesized in a high-density Plasma-Enhanced Chemical Vapor Deposition (PECVD) process that provides a high degree of control of the growth conditions and, consequently, the resultant electronic properties. After inspection of fiber morphology and composition using scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) analysis, a layer of SiO2 was deposited conformally onto the fibers by a silane-based RF PECVD process. Following planarization of the substrates by chemical mechanical polishing, the tips of the fibers were uncoverd by reactive ion etching of the SiO2 layer. Electrodes were patterned on the substrate surface to make contact to individual fiber tips within the array. Current versus voltage (I-V) curves indicate the presence of a metal-semiconductor (Schottky) junction and display a rectifying behavior. I-V measurements made with respect to temperature reveal an average barrier height of 300 mV. Additional experiments indicate that the junction occurs at the nanofiber/silicon interface. An empirical model of the material system will be presented along with an explanation of the experimentally observed charge transport behavior.