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Table of Contents Examining Committee Membership …………………………………………………………………………………………. ii Author’s Declaration ……………………………………………………………………………………………………………… iii Statement of Contributions …………………………………………………………………………………………………….. iv Abstract ……………………………………………………………………………………………………………………………….. v Rsum ………………………………………………………………………………………………………………………………. vii Acknowledgements …………………………………………………………………………………………………………….. viii Dedication …………………………………………………………………………………………………………………………… ix List of Figures ……………………………………………………………………………………………………………………. xiv List of Tables ……………………………………………………………………………………………………………………. xxiv List of Equations ………………………………………………………………………………………………………………. xxvi List of Schemes ……………………………………………………………………………………………………………….. xxvii List of Abbreviations ……………………………………………………………………………………………………….. xxviii Land Acknowledgement …………………………………………………………………………………………………….. xxxi Tribute to Nanotubes ………………………………………………………………………………………………………… xxxii Chapter 1 : Introduction………………………………………………………………………………………………………….. 1 : Background and Literature Review ……………………………………………………………………………….. 3 Primer on Carbon Nanotubes …………………………………………………………………………………… 3 Fabricating Carbon Nanotubes ……………………………………………………………………………….. 10 Carbon Nanotube Defects ………………………………………………………………………………………. 19 Carbon Nanotube Electronic Properties …………………………………………………………………… 21 Carbon Nanotubes as Transistors ……………………………………………………………………………. 27 Carbon Nanotube Sorting ………………………………………………………………………………………. 33 Carbon Nanotube Alignment ………………………………………………………………………………….. 36 Carbon Nanotube Alignment and Sorting ………………………………………………………………… 41 Alignment Relay Technique …………………………………………………………………………………………. 44 Intermolecular Interactions with SWNTs …………………………………………………………………. 44 Substrate Binding …………………………………………………………………………………………………. 47 Surface Oxidation and Cleaning ……………………………………………………………………………… 49 Liquid Crystal Technology …………………………………………………………………………………….. 51 Synthesis of the CNT Tweezer in ART ……………………………………………………………………. 54 ART Process ………………………………………………………………………………………………………… 55 xi Characterization methods …………………………………………………………………………………………….. 58 Atomic Force Microscopy ……………………………………………………………………………………… 58 Scanning Electron Microscopy ……………………………………………………………………………….. 61 IR and Raman Spectroscopy ………………………………………………………………………………….. 64 I-V Testing…………………………………………………………………………………………………………… 71 Additional Techniques …………………………………………………………………………………………… 77 Concluding Remarks …………………………………………………………………………………………………… 80 Chapter 2 : Modifications to the ART Procedure ……………………………………………………………………… 81 Post-Carbon Nanotube Deposition: Sonication ……………………………………………………………….. 81 Results and Discussion ………………………………………………………………………………………….. 82 Summary of Sonication Experiments …………………………………………………………………….. 116 Post-Carbon Nanotube Deposition: Layer-by-Layer (LBL) treatment ……………………………… 118 Results and Discussion ………………………………………………………………………………………… 118 Langmuir-Blodgett Attempt …………………………………………………………………………………. 121 Summary …………………………………………………………………………………………………………… 122 Pre-Carbon Nanotube Deposition: Filler Molecules ………………………………………………………. 123 Concept and Experiment ……………………………………………………………………………………… 123 Results and Discussion ………………………………………………………………………………………… 124 Summary of Filler Molecule Experiments on SiO2 ………………………………………………….. 129 Chapter 3 : Different Anchoring Group and Substrate Surfaces ……………………………………………….. 131 Alumina coated surface ……………………………………………………………………………………………… 131 Substituting a Carboxylic Acid as an Anchoring group ……………………………………………. 133 Substituting 5CB for 8CB ……………………………………………………………………………………. 138 Filler Exploration………………………………………………………………………………………………… 140 a-Al2O3 (Sapphire) ……………………………………………………………………………………………… 144 Au coated surface ……………………………………………………………………………………………………… 147 Sulfur Anchoring Component for Au …………………………………………………………………….. 149 Gold with Filler Molecules Adaptation ………………………………………………………………….. 151 Further Directions for Sulfur in ART …………………………………………………………………….. 155 SiNX, TiO2 and using UV-Ozone cleaning ……………………………………………………………………. 156 Summary of Different Anchoring Groups and Substrate Surface Investigations ………….. 159 Chapter 4 : Other nanosystems probed for alignment ……………………………………………………………… 160 Hydrophilic Carboxylic-acid functionalized SWNTs …………………………………………………….. 160 xii Analysis of 78% purity SWNTs ……………………………………………………………………………. 161 Synthesis of SWNTs-COOH ………………………………………………………………………………… 163 Results and Discussion for SWNTs-COOH ……………………………………………………………. 164 Summary of SWNTs-COOH studies ……………………………………………………………………… 169 Longer SWNTs …………………………………………………………………………………………………………. 171 Smaller Diameter SWNTs ………………………………………………………………………………………….. 173 Multi-Walled Carbon Nanotubes ………………………………………………………………………………… 174 Graphene Nano-Ribbons ……………………………………………………………………………………………. 181 Nanowires ………………………………………………………………………………………………………………… 183 Graphene and Graphene Quantum Dots ……………………………………………………………………….. 185 Summary of ART for Other Nanosystems ……………………………………………………………………. 186 Chapter 5 : Applying ART toward SWNTs device fabrication …………………………………………………. 187 Device Fabrication ……………………………………………………………………………………………………. 187 Optimization of LED lithography………………………………………………………………………….. 187 E-beam lithography …………………………………………………………………………………………….. 191 Device Testing ………………………………………………………………………………………………………….. 192 Annealing Tests ………………………………………………………………………………………………….. 193 Bottom Gate Devices …………………………………………………………………………………………… 200 Top Gate Devices ……………………………………………………………………………………………….. 207 Ionic Gel Gate…………………………………………………………………………………………………….. 214 Substitution of Metal Electrodes …………………………………………………………………………… 216 Additional Imaging ……………………………………………………………………………………………………. 217 TEM of CNTFETs ………………………………………………………………………………………………. 217 Interesting Patterning Observation ………………………………………………………………………… 218 Summary …………………………………………………………………………………………………………………. 220 Chapter 6 : Concluding Remarks & Future Directions ……………………………………………………………. 221 Chapter 7 : Experimental …………………………………………………………………………………………………….. 226 Sample Preparation for the Alignment Relay Technique ………………………………………………… 226 Sonication Experiments ……………………………………………………………………………………………… 229 Application of Fillers …………………………………………………………………………………………………. 229 SWNTs-COOH synthesis and surfactant free treatment …………………………………………………. 229 Langmuir Blodgett- ART combination ………………………………………………………………………… 230 Other Nanostructures for Alignment with ART: NWs, GNRs, and MWNTs …………………….. 230 xiii Characterization of ART substrates ……………………………………………………………………………… 231 Atomic Force Microscopy ……………………………………………………………………………………. 231 Scanning electron microscopy ………………………………………………………………………………. 232 X-Ray Photoelectron Spectroscopy ……………………………………………………………………….. 232 UV-vis spectroscopy …………………………………………………………………………………………… 232 Ellipsometry ………………………………………………………………………………………………………. 233 Raman Spectroscopy …………………………………………………………………………………………… 233 Alignment Data Analysis …………………………………………………………………………………….. 235 Synthesis ………………………………………………………………………………………………………………….. 236 Attempted yet unsuccessful molecular synthesis …………………………………………………….. 250 Field-effect Transistor Fabrication and Testing …………………………………………………………….. 251 LED Photolithography Patterning …………………………………………………………………………. 251 Electron Beam Lithography Patterning ………………………………………………………………….. 252 Metal Deposition ………………………………………………………………………………………………… 254 Electrical Testing ………………………………………………………………………………………………… 254 Probe-test …………………………………………………………………………………………………………… 254 Copyright Permissions ……………………………………………………………………………………………………….. 256 References ………………………………………………………………………………………………………………………… 257 Appendix: Supplemental Data ……………………………………………………………………………………………… 274 Appendix Chapter 2 ………………………………………………………………………………………………………… 274 Sonication Experiments ……………………………………………………………………………………………….. 274 LBL and LB Experiments ……………………………………………………………………………………………. 286 Filler Experiments ………………………………………………………………………………………………………. 289 Appendix Chapter 3 ………………………………………………………………………………………………………… 291 Appendix Chapter 4 ………………………………………………………………………………………………………… 300 SWNTs-COOH ………………………………………………………………………………………………………….. 300 Longer length SWNTs …………………………………………………………………………………………………. 312 Smaller diameter SWNTs …………………………………………………………………………………………….. 313 Bottom-up synthesized GNRs Raman ……………………………………………………………………………. 317 MWNTs …………………………………………………………………………………………………………………….. 318 Graphene …………………………………………………………………………………………………………………… 318 Appendix Chapter 5 ………………………………………………………………………………………………………… 319 Appendix Chapter 6 ………………………………………………………………………………………………………… 331
