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Abstract
This thesis details the pioneering synthesis of (2,1) SWCNTs within the channels of Zeolite Socony Mobil–5 (ZSM-5). Zeolite is materials with a well-defined microporous structure, which could be made use to act as a template for growth of nanowires or other 1D materials. The primary objective of this research is to develop a reliable and scalable method for producing (2,1) SWCNTs by leveraging the structural characteristics of ZSM-5 to direct the growth of nanotubes with desired electronic properties.
The methodology centers on a chemical vapor deposition (CVD) to initiate the growth of SWCNTs. Key to the synthesis process is the precise control of the optimization of growth conditions such as temperature, pressure, and gas flow rates. Scanning electron microscopy (SEM), Raman spectroscopy, thermal gravimetric analysis (TGA) and superconducting quantum interference device (SQUID) were employed to characterize the morphology and confirm the chirality of the SWCNTs.
The results demonstrate successful synthesis of (2,1) SWCNTs predominantly inside the ZSM-5 channels. Raman spectroscopy provided further confirmation, showing the characteristic radial breathing modes corresponding to (2,1) SWCNTs. The embedded SWCNTs have high degree of structural integrity and alignment.
Doping of boron into (2,1) SWCNTs were made by introducing diborane gas (2𝐵2𝐻6) during the CVD process, in order to alter the electronic properties of (2,1) SWCNTs. Electronic transport measurement had been carried out in cryogenic system and the result would be discussed in this thesis. A smooth drop in resistance at low temperature was observed. The response to voltage and magnetic field would also be reported.
In the first chapter, we would illustrate the basic lattice structure and electronic structure of carbon nanotubes, with introduction of typical fabrication methods and theories of superconductivity. Then characterization methods of Raman spectroscopy and TGA would be discussed in chapter 2. Fabrication methods in detail would be reported in chapter 3. In the last chapter, we would show the measurement result of electrical transport measurement and magnetic susceptibility.