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Title:Approaches for alignment and purification of single walled carbon nanotube thin films and their application in device electronics
Author(s):Dunham, Simon
Director of Research:Rogers, John A.
Doctoral Committee Chair(s):Rogers, John A.
Doctoral Committee Member(s):Braun, Paul V.; Dillon, Shen J.; Pop, Eric
Department / Program:Materials Science & Engineerng
Discipline:Materials Science & Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):single walled carbon nanotube
metallic removal
nanotube growth
Abstract:Thin films that consist of dense horizontally aligned arrays of semiconducting single walled carbon nanotubes (SWNTs) represent one of the most promising materials for low cost, high performance electronic today. Over the years, a great deal of progress has been made towards this goal, however, to date, there are still key challenges associated with achieving films with the required density, degree of alignment and without the presence of metallic single walled carbon nanotubes. Here, we present fundamental studies of well-established techniques for chemical vapor deposition growth of aligned arrays and present a model for understanding this alignment based on strong Van der Waals interactions between the SWNT and the substrate. This model is experimentally validated through detailed study of alignment a variety of crystalline surfaces of quartz. Furthermore, the study reveals that current limitations to growth density are not intrinsic to the mode of alignment suggesting the potential for dramatic improvements in growth density. Additionally, we present a methodology for purifying these arrays based on selective, joule heating induced thermocapillary flow in thin organic layers deposited on the array that is localized to the metallic SWNTs and subsequent etching to yield their removal. We provide statistically significant demonstrations to prove the effectiveness and selectivity of this approach and study the underlying physics of joule induced thermocapillary flow, which is critical to the effectiveness. Finally, we illustrate the scalability of this approach. Lastly, we present several demonstrations of electronic devices based on aligned arrays (both purified and unpurified) and detailed characterization of their performance.
Issue Date:2013-02-03
Rights Information:Copyright 2012 Simon Dunham
Date Available in IDEALS:2013-02-03
Date Deposited:2012-12

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