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ISRN Nanomaterials
Volume 2012 (2012), Article ID 971854, 5 pages
http://dx.doi.org/10.5402/2012/971854
Research Article

Study of J-E Curve with Hysteresis of Carbon Nanotubes Field Emitters

Department of Physics, Jamia Millia Islamia, New Delhi 110025, India

Received 7 June 2012; Accepted 15 July 2012

Academic Editors: J. Escrig, G. Jin, and A. Kajbafvala

Copyright © 2012 Shama Parveen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We observe hysteresis in J-E plot during field emission measurement of CNTs grown by LPCVD technique. CNTs are synthesized on Fe-coated Si substrate at 650°C. SEM and Raman study confirm that CNTs are successfully grown on Si substrate by LPCVD technique. In this study, we find that ramp-down curve has higher value of current density than ramp-up curve which indicates that CNTs show positive hysteresis. Our results show that a high current density at low turn-on voltage is obtained in ramp-down step of J-E plot which may be since not all CNTs contribute in ramp-up step process. But in ramp-down step all CNTs contribute as field emitters due to high electric field treatment. We also performed stability analysis of CNTs with current at constant applied voltage for 5 hrs and find that the sample shows long-term stability due to increase in emitting site density since a large number of CNTs participate in field emission.