Li, Jianan
(2019)
GRAPHENE-COMPLEX OXIDE HETEROSTRUCTURE.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Graphene and complex-oxide heterostructures are both 2D systems that have initiated numerous research areas. The two-dimensional electron gas (2DEG) in both systems differs in many ways from traditional semiconductor materials. This research is dedicated to integrating these two versatile systems. Conventionally, the transfer of graphene grown by chemical vapor deposition is assisted by poly(methyl methacrylate) (PMMA). A new transfer method is developed in this research and can protect the graphene against contaminations. The graphene transferred onto the complex-oxide heterostructure substrates using such method is atomically clean with high mobility. Conductive atomic force microscope (c-AFM) writing technique is applied to graphene-complex-oxide heterostructure to reversibly control the charge-neutrality point (CNP) with nanoscale resolution, utilizing the tunability of the complex-oxide substrate. The local electron density and conductivity of the complex-oxide heterostructure interface can be patterned with the c-AFM tip, and the CNP of the proximal graphene is shifted. With this effect, the mixing of edge state in quantum Hall regime on the edge of graphene p-n junctions can be reversibly controlled. Quantization of resistance is observed as a result of the mixing at low temperature, depending on the directions of currents and magnetic fields. Nanoscale devices such as superlattices can also be produced on various two-dimensional material heterostructure by combining these two techniques.
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| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
27 September 2019 |
| Date Type: |
Publication |
| Defense Date: |
15 April 2019 |
| Approval Date: |
27 September 2019 |
| Submission Date: |
7 April 2019 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
156 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Physics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Graphene, oxide, nanotechnology |
| Date Deposited: |
27 Sep 2019 15:49 |
| Last Modified: |
27 Sep 2019 15:49 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/36395 |
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