Masters Theses

Date of Award

12-2001

Degree Type

Thesis

Degree Name

Master of Science

Major

Electrical Engineering

Major Professor

Michael L. Simpson

Committee Members

Syed K. Islam, Doug H. Lowndes

Abstract

This thesis presents research involving the electrical characterization of single-walled carbon nanotubes produced by the pulsed-laser vaporization technique. Carbon nanotubes were suspended in organic solvents and separated using ultrasonic excitation. The dispersed nanotubes were either physically deposited or spin-deposited onto electrode structures that were prefabricated using standard electron-beam lithography. Atomic force microscopy was used to locate and measure nanotubes that spanned across metal electrodes. Two-probe charge transport measurements were then made on these nanotube samples. The first sample exhibited current rectification, while many other carbon nanotubes were damaged by electrical breakdown. The effect of manipulating a nanotube at the electrode junction is also demonstrated. It was found that a potential barrier could be introduced, changing the I-V response of the nanotube device. Then, p-channel field-effect transistor behavior is shown for an individual single-walled carbon nanotube. Finally, an electrodeposition technique is presented for reducing the large contact resistance between a nanotube and the metal electrodes. This technique decreased the electrode-nanotube contact resistance by a factor of more than six, and maintained the semiconducting behavior of the nanotube. Energy band diagram models are used to try to explain some of the observed electronic properties.

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