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OverviewThis thesis addresses the problem of improving the alignment of carbon nanotubes (CNTs) in transistor applications, taking a unique approach using iptycenes acting as molecular tweezers in combination with a liquid crystal solvent. As part of a project to test the effectiveness of a multi-step method, the so-called Alignment Relay Technique (ART), this work contributed evidence for the selectivity and stability of ART, as well as providing the first proof-of-concept that ART can be used to create CNT field-effect transistors (FETs). The thesis effectively explains and illustrates the chemical synthesis of the tweezers, the concept and actualization of the technique, the various factors observed to influence deposition and selectivity, along with material fabrication using both photolithography and electron beam lithography. This research advances knowledge of transistors and expands the applications of small organic molecules in the field of materials science. Particular highlights of this thesis include: an extensive review of ART, its advantages, and limitations; development of new material chemistry methods for the optimization of semiconducting CNT selectivity; and a comprehensive exploration of fabrication and characterization of CNTFETs for future applications. Full Product DetailsAuthor: Monika SnowdonPublisher: Springer Nature Switzerland AG Imprint: Springer Nature Switzerland AG Edition: 1st ed. 2021 Weight: 0.450kg ISBN: 9783030844158ISBN 10: 3030844153 Pages: 263 Publication Date: 10 November 2022 Audience: Professional and scholarly , Professional & Vocational Format: Paperback Publisher's Status: Active Availability: Manufactured on demand  We will order this item for you from a manufactured on demand supplier. Table of ContentsTable of ContentsExamining Committee Membership ....................................................................................................... iiAuthor's Declaration .............................................................................................................................. iiiStatement of Contributions .................................................................................................................... ivAbstract .................................................................................................................................................. vRésumé ................................................................................................................................................. viiAcknowledgements ............................................................................................................................. viiiDedication ............................................................................................................................................. ixList of Figures ..................................................................................................................................... xivList of Tables ..................................................................................................................................... xxivList of Equations ............................................................................................................................... xxviList of Schemes ................................................................................................................................ xxviiList of Abbreviations ....................................................................................................................... xxviiiLand Acknowledgement .................................................................................................................... xxxiTribute to Nanotubes ........................................................................................................................ xxxiiChapter 1 : Introduction.......................................................................................................................... 1: Background and Literature Review ............................................................................................ 3Primer on Carbon Nanotubes ................................................................................................ 3Fabricating Carbon Nanotubes ............................................................................................ 10Carbon Nanotube Defects .................................................................................................... 19Carbon Nanotube Electronic Properties .............................................................................. 21Carbon Nanotubes as Transistors ........................................................................................ 27Carbon Nanotube Sorting .................................................................................................... 33Carbon Nanotube Alignment ............................................................................................... 36Carbon Nanotube Alignment and Sorting ........................................................................... 41Alignment Relay Technique ....................................................................................................... 44Intermolecular Interactions with SWNTs ............................................................................ 44Substrate Binding ................................................................................................................ 47Surface Oxidation and Cleaning .......................................................................................... 49Liquid Crystal Technology .................................................................................................. 51Synthesis of the CNT Tweezer in ART ............................................................................... 54ART Process ........................................................................................................................ 55xiCharacterization methods ........................................................................................................... 58Atomic Force Microscopy ................................................................................................... 58Scanning Electron Microscopy ............................................................................................ 61IR and Raman Spectroscopy ............................................................................................... 64I-V Testing........................................................................................................................... 71Additional Techniques ......................................................................................................... 77Concluding Remarks .................................................................................................................. 80Chapter 2 : Modifications to the ART Procedure ................................................................................. 81Post-Carbon Nanotube Deposition: Sonication .......................................................................... 81Results and Discussion ........................................................................................................ 82Summary of Sonication Experiments ................................................................................ 116Post-Carbon Nanotube Deposition: Layer-by-Layer (LBL) treatment .................................... 118Results and Discussion ...................................................................................................... 118Langmuir-Blodgett Attempt .............................................................................................. 121Summary ........................................................................................................................... 122Pre-Carbon Nanotube Deposition: Filler Molecules ................................................................ 123Concept and Experiment ................................................................................................... 123Results and Discussion ...................................................................................................... 124Summary of Filler Molecule Experiments on SiO2 ........................................................... 129Chapter 3 : Different Anchoring Group and Substrate Surfaces ........................................................ 131Alumina coated surface ............................................................................................................ 131Substituting a Carboxylic Acid as an Anchoring group .................................................... 133Substituting 5CB for 8CB ................................................................................................. 138Filler Exploration............................................................................................................... 140α-Al2O3 (Sapphire) ............................................................................................................ 144Au coated surface ..................................................................................................................... 147Sulfur Anchoring Component for Au ................................................................................ 149Gold with Filler Molecules Adaptation ............................................................................. 151Further Directions for Sulfur in ART ................................................................................ 155SiNX, TiO2 and using UV-Ozone cleaning ............................................................................... 156Summary of Different Anchoring Groups and Substrate Surface Investigations .............. 159Chapter 4 : Other nanosystems probed for alignment ........................................................................ 160Hydrophilic Carboxylic-acid functionalized SWNTs .............................................................. 160xiiAnalysis of 78% purity SWNTs ........................................................................................ 161Synthesis of SWNTs-COOH ............................................................................................. 163Results and Discussion for SWNTs-COOH ...................................................................... 164Summary of SWNTs-COOH studies ................................................................................. 169Longer SWNTs ......................................................................................................................... 171Smaller Diameter SWNTs ........................................................................................................ 173Multi-Walled Carbon Nanotubes ............................................................................................. 174Graphene Nano-Ribbons .......................................................................................................... 181Nanowires ................................................................................................................................. 183Graphene and Graphene Quantum Dots ................................................................................... 185Summary of ART for Other Nanosystems ............................................................................... 186Chapter 5 : Applying ART toward SWNTs device fabrication .......................................................... 187Device Fabrication ................................................................................................................... 187Optimization of LED lithography...................................................................................... 187E-beam lithography ........................................................................................................... 191Device Testing .......................................................................................................................... 192Annealing Tests ................................................................................................................. 193Bottom Gate Devices ......................................................................................................... 200Top Gate Devices .............................................................................................................. 207Ionic Gel Gate.................................................................................................................... 214Substitution of Metal Electrodes ....................................................................................... 216Additional Imaging ................................................................................................................... 217TEM of CNTFETs ............................................................................................................. 217Interesting Patterning Observation .................................................................................... 218Summary .................................................................................................................................. 220Chapter 6 : Concluding Remarks & Future Directions ...................................................................... 221Chapter 7 : Experimental .................................................................................................................... 226Sample Preparation for the Alignment Relay Technique ......................................................... 226Sonication Experiments ............................................................................................................ 229Application of Fillers ................................................................................................................ 229SWNTs-COOH synthesis and surfactant free treatment .......................................................... 229Langmuir Blodgett- ART combination .................................................................................... 230Other Nanostructures for Alignment with ART: NWs, GNRs, and MWNTs .......................... 230xiiiCharacterization of ART substrates .......................................................................................... 231Atomic Force Microscopy ................................................................................................. 231Scanning electron microscopy ........................................................................................... 232X-Ray Photoelectron Spectroscopy ................................................................................... 232UV-vis spectroscopy ......................................................................................................... 232Ellipsometry ...................................................................................................................... 233Raman Spectroscopy ......................................................................................................... 233Alignment Data Analysis .................................................................................................. 235Synthesis ................................................................................................................................... 236Attempted yet unsuccessful molecular synthesis .............................................................. 250Field-effect Transistor Fabrication and Testing ....................................................................... 251LED Photolithography Patterning ..................................................................................... 251Electron Beam Lithography Patterning ............................................................................. 252Metal Deposition ............................................................................................................... 254Electrical Testing ............................................................................................................... 254Probe-test ........................................................................................................................... 254Copyright Permissions ....................................................................................................................... 256References .......................................................................................................................................... 257Appendix: Supplemental Data ............................................................................................................ 274Appendix Chapter 2 ........................................................................................................................ 274Sonication Experiments .............................................................................................................. 274LBL and LB Experiments .......................................................................................................... 286Filler Experiments ...................................................................................................................... 289Appendix Chapter 3 ........................................................................................................................ 291Appendix Chapter 4 ........................................................................................................................ 300SWNTs-COOH .......................................................................................................................... 300Longer length SWNTs ................................................................................................................ 312Smaller diameter SWNTs ........................................................................................................... 313Bottom-up synthesized GNRs Raman ........................................................................................ 317MWNTs ...................................................................................................................................... 318Graphene .................................................................................................................................... 318Appendix Chapter 5 ........................................................................................................................ 319Appendix Chapter 6 ........................................................................................................................ 331ReviewsAuthor InformationMonika obtained her doctorate in chemistry from the University of Waterloo, Canada. Part of her doctoral research was pursued in Japan at the soft materials chemistry group under the supervision of Dr. Dai-Ming Tang at the National Institute for Material Science. She holds a MSc in organosulfur synthesis and a BSc in nanoscience from the University of Guelph, Canada. Currently, she is a postdoctoral researcher in mechanical engineering at Dr. Zhou's lab as part of the Center for Advanced Materials Joining, University of Waterloo, and a lead product developer with Elizion Tech. Tab Content 6Author Website:Countries AvailableAll regions |
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