Integration of aligned arrays of single-walled carbon nanotubes in electronic devices

Ho, Xinning

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https://hdl.handle.net/2142/24308 Copy

Description

Title

Integration of aligned arrays of single-walled carbon nanotubes in electronic devices

Author(s)

Ho, Xinning

Issue Date

2011-05-25T14:50:01Z

Director of Research (if dissertation) or Advisor (if thesis)

Rogers, John A.

Doctoral Committee Chair(s)

Rogers, John A.

Committee Member(s)

• Abelson, John R.
• Pop, Eric
• Shim, Moonsub
• Li, Xiuling

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• carbon nanotubes
• electroluminescence
• transistor
• aligned arrays
• Schottky diode
• diameter distribution

Abstract

Aligned arrays of single-walled carbon nanotubes (SWNTs) are an attractive format for macroelectronics and RF analog electronics with exceptional electrical, mechanical and optical properties. Unlike isolated SWNT, the presence of many SWNTs in the aligned arrays increases the current output and statistical averaging in many SWNTs is expected to reduce the device to device variations. The SWNTs in aligned arrays do not intersect one another, unlike in networks of SWNTs. Hence, tube/tube contacts, which limit the transport in SWNT networks due to tunneling barriers or electrostatic screening at the contacts to prevent effective gate modulation at those specific points, are absent. Nonetheless, challenges still remain for these aligned arrays of SWNTs before their successful integration into electronic devices for large scale commercial use. The main challenges include (1) selective elimination of m-SWNTs, (2) increasing the density of SWNTs, (3) achieving electronic uniformity across devices fabricated and (4) understanding their mode of operation and the role of contacts in their operation. In this dissertation, I present a study that aims to tackle the 3rd and 4th challenges aforementioned. We integrated these arrays of SWNT thin films into field effect transistors to study the electronic uniformity of the devices. We examined the effect of variation in density and diameter distributions of the aligned arrays of SWNTs on the variation in the electrical performance of the transistors. We also analyzed the properties of the contacts at the SWNT/metal interface. We found Pd to be a good Ohmic contact and Ca to be a Schottky contact to the aligned arrays of SWNTs and went on to fabricate Schottky diodes. Using these Schottky diodes, we demonstrated light emitting diodes with aligned arrays of SWNTs which could be used in novel applications that require solid state and nano-scale infra-red emitters. Work done to selectively eliminate m-SWNTs (1st challenge) via selective laser ablation is also archived in this dissertation. These results represent important steps in understanding the device performance of transistors and Schottky diodes based on aligned arrays of SWNTs; which may have a large impact in large area RF analog electronics.

Graduation Semester

2011-05

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http://hdl.handle.net/2142/24308

Copyright and License Information

Copyright 2011 Xinning Ho

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