Author

Sherif Tawfik

Abstract

We investigated the mechanism of electron field emission in prestine short carbon nanotubes using ab-initio computation in isolated and periodic simulation cells. We computed the evolution of the wave functions using Time-Dependent Density Functional Theory, where we have utilized the Crank-Nicholson propagator. We found that in prestine carbon nanotubes, emitted charge tends emerge mostly from electrons that are concentrated at the nanotube tip region, unlike metallic tips. The charge beam concentrates into specific channel structures as the wave function approaches the anode. Nitrogen doping of carbon nanotubes improves emission, in line with experimental findings, and the nitrogen dopant closer to the nanotube tip produces optimal emission performance. However, the nitrogen dopant causes dispersion of the charge cloud, which might lead to wasting of the emission current. Boron doping either impedes field emission in nanotubes or produces minimal effect.

Department

Physics Department

Degree Name

MS in Physics

Date of Award

6-1-2011

Online Submission Date

September 2010

First Advisor

El Sheikh, Salah

Second Advisor

Salem, Noha

Document Type

Thesis

Extent

NA

Library of Congress Subject Heading 1

Carbon.

Library of Congress Subject Heading 2

nostructured materials.

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.

IRB

Not necessary for this item

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