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|Title: ||Towards self-assembled devices, a carbon nanotube approach|
|Authors: ||Del Rio Castillo, Antonio Esau|
|Supervisor/Tutor: ||Prato, Maurizio|
|Co-supervisor: ||Bonaccorso, Francesco|
|Issue Date: ||26-Mar-2012|
|Publisher: ||Università degli studi di Trieste|
|Abstract: ||In the last decade the nanostructured carbon materials, especially single walled carbon nanotubes (SWNTs), had emerged as probable substitutes for Silicon in the next generation of electronic devices. This is due to their unique physic and chemical properties. Likewise, scientists all around the world have made a huge effort to introduce carbon materials into the market. Despite this effort, commercial application for carbon nanotubes in electronic devices has not yet been achieved. The hindrances are due to two reasons mainly: the first one is for the physico-chemical properties of carbon nanotubes; for example, the strong π-π interactions between nanotube creates thick bundles; in the pristine form CNTs are almost indispersible in any solvent; nanotubes are practically inert chemically; and finally the synthesis of SWNTs produces a mixture of semiconducting and metallic nanotubes. The second hindrance is related to the device construction and characteristics, e. g. the high contact resistance between SWNT and electrodes, the selection of electrode materials, the gate dielectric structure and material are also importants, and finally how the SWNT is contacted with electrodes.
In my opinion, if it is desired to use a new material in high technology applications, will be necessary to use new methodologies and break paradigms. In this work I try to mimic what nature does, assemble objects from the bottom up. So, for the bottom up construction of the device I combine the assembly qualities of organic chemistry and the physical properties of inorganic materials. In this way, to deal with the challenges of construction and improvement of the “next device generation” I used non-conventional procedures in electronic devices: sol-gel process for the synthesis of the gate dielectric; organic chemistry for improvement on the electrodes-nanotube resistance; and propose the use of DNA origami as general assembly process for the device. For the sorting of nanotubes it is applied a top-down approach, the current technologies in the synthesis of SWNTs are not able to render a single electric behaviour yet.
The scope of this work is to demonstrate that it is feasible to use bottom up techniques in the construction of devices, replacing the use of “top down” processes that are currently in use in the silicon industry.
The thesis is organized as follows:
• In the chapter 1 the carbon materials characteristics are introduced and how they can change the actual Silicon technologies. Additionally a brief review the electronic and optical properties of SWNTs, including the optical spectroscopy techniques used for their characterization: absorption and Raman.
• Chapter 2 discuses briefly the grow methodologies of SWNTs, the as-produced characteristics, purification techniques and sorting by electronic behaviour. Graphene exfoliation is reviewed.
• Chapter 3 deals with the design and synthesis of the dielectric material on SWNTs and over graphene. Sol gel process is briefly explained.
• In chapter 4 is explained the synthesis of metallic nanoparticles and the selective linking with SWNTs.
• Chapter 5 is dedicated to perspectives and further work, concerning mainly to device assembly, focusing in the manipulation of DNA and SWNTs.
This work has been supported by the National Council for Science and Technologies, CONACyT (Mexican Government).|
|PhD cycle: ||XXIV Ciclo|
|PhD programme: ||SCUOLA DI DOTTORATO DI RICERCA IN SCIENZE E TECNOLOGIE CHIMICHE E FARMACEUTICHE|
|Keywords: ||carbon nanotubes|
|Main language of document: ||en|
|Type: ||Tesi di dottorato|
|Scientific-educational field: ||CHIM/06 CHIMICA ORGANICA|
|Appears in Collections:||Scienze chimiche|
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