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Proceedings Paper

Thermal instability of field emission from carbon nanotubes studied using multi-physics simulation by considering space charge effect
Author(s): A. E. Islam; S. B. Fairchild; B. Maruyama
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Paper Abstract

Thermal instability is an important concern for practical use of high-current field emitters in display, X-ray generation, Hall thruster, and microplasma generation. Carbon nanotubes (CNTs) and their bundles have high thermal conductivity and offers great promise in this aspect. A wide-range of experiments has recently been performed with CNT-based emitters containing single or a bundle of nanotubes. Analysis of these experiments is executed using the classical Fowler-Nordheim (FN) equation and the heat equation with no self-consistency. The space-charge effect – one of the most important aspect of high-current field emission – is often ignored in these theoretical analyses. In this work, we use a numerical framework to study thermal instability in the CNT-based emitters by solving electrostatics, space-charge effect, quantum-mechanical tunneling (with FN equation as the limiting case), thermionic emission and heat flow in a self-consistent manner. Simulation compares well with the experimental results and allows study of temperature rise – the root cause of thermal instability – for the emitter in a wide range of conditions. Our analysis suggests that higher thermal conductivity and/or electrical conductivity and their reduced temperature dependence are beneficial for the field emitters, as these improve the thermal stability of the emitter by reducing temperature rise.

Paper Details

Date Published: 16 September 2015
PDF: 9 pages
Proc. SPIE 9552, Carbon Nanotubes, Graphene, and Emerging 2D Materials for Electronic and Photonic Devices VIII, 95520B (16 September 2015); doi: 10.1117/12.2187331
Show Author Affiliations
A. E. Islam, Air Force Research Lab. (United States)
National Research Council (United States)
S. B. Fairchild, Air Force Research Lab. (United States)
B. Maruyama, Air Force Research Lab. (United States)

Published in SPIE Proceedings Vol. 9552:
Carbon Nanotubes, Graphene, and Emerging 2D Materials for Electronic and Photonic Devices VIII
Manijeh Razeghi; Maziar Ghazinejad; Can Bayram; Jae Su Yu; Young Hee Lee, Editor(s)

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