Methods of the Alignment-Relay Technique for Nanosystems

This 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.

Auteur

Monika 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.

Contenu

Table 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 ............................................…