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Physics and Applications of Graphene-Based Nanostructures and Nano-Meta Materials

Citation

Hsu, Chen-Chih (2020) Physics and Applications of Graphene-Based Nanostructures and Nano-Meta Materials. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/6T02-4X35. https://resolver.caltech.edu/CaltechTHESIS:03172020-153749505

Abstract

Graphene, a single layer of carbon atoms forming a honeycomb lattice structure, has been considered a wonder material for both scientific research and technological applications. Structural distortions in nano-materials can induce dramatic changes in their electronic properties. In particular, strained graphene can result in both charging effects and pseudo-magnetic fields, so that controlled strain on a perfect graphene lattice can be tailored to yield desirable electronic properties.

In the first part of this thesis (Chapter 2 to 5), we explore a new approach to manipulating the topological states in monolayer graphene via nanoscale strain engineering. By placing strain-free monolayer graphene on architected nanostructures to induce global inversion symmetry breaking, we demonstrate the development of giant pseudo-magnetic fields, global valley polarization, and periodic one-dimensional topological channels for protected propagation of chiral modes in strained graphene. We have also observed pseudo-magnetic field-induced quantum oscillations and valley Hall signals, including quantum valley Hall effect, by transport measurements at 1.8K.

The second part of this thesis focuses on the development and applications of other graphene-based nanostructures. We report PECVD techniques for the synthesis of various graphene and graphene-based nanostructures, including horizontal growth of graphene sheets, vertical growth of graphene nanostructures such as graphene nanostripes with large aspect ratios, and direct and selective deposition of multi-layer graphene on nanostructured substrates. By properly controlling the gas environment of the plasma, it is found that no active heating is necessary for the PECVD growth processes and that high-yield growth can take place in a single step on a variety of surfaces, including metallic, semiconducting, and insulating materials.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Graphene; strain; pseudomagnetic field; valley hall effect; valleytronics; graphene nanostripes
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Not set
Research Advisor(s):
  • Yeh, Nai-Chang
Thesis Committee:
  • Roukes, Michael Lee (chair)
  • Yeh, Nai-Chang
  • Alicea, Jason F.
  • Hsieh, David
Defense Date:16 December 2019
Record Number:CaltechTHESIS:03172020-153749505
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:03172020-153749505
DOI:10.7907/6T02-4X35
Related URLs:
URLURL TypeDescription
https://doi.org/10.1038/ncomms7620DOIArticle adapted for Chapters 2 and 3.
https://doi.org/10.1007/s10409-015-0548-9DOIArticle adapted for Chapters 2 and 4.
https://doi.org/10.1088/1361-6528/aafdbfDOIArticle adapted for Chapters 3 and 7.
https://doi.org/10.1016/j.carbon.2017.12.058DOIArticle adapted for Chapter 6.
ORCID:
AuthorORCID
Hsu, Chen-Chih0000-0003-1130-5240
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13660
Collection:CaltechTHESIS
Deposited By: Chen Chih Hsu
Deposited On:27 Mar 2020 23:51
Last Modified:30 Mar 2021 15:48

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