Fabrication and electrical properties of topological insulator thin films
- Topological insulators are a special category of materials that are insulating in the bulk but have robust conducting surface states. As an ideal candidate for low power electronics, spintronic and quantum computation, topological insulators have been actively studied both theoretically and experimentally in the past couple of years. To achieve high quality thin films of topological insulators and understand their properties thoroughly is a critical step towards all potential applications. In this dissertation, I will introduce methods to fabricate high quality topological insulator Bi2Se3 thin films using both pulsed laser deposition (PLD) and molecular beam epitaxy (MBE) with a radio frequency (RF) cracker cell. Using PLD, bilayers of topological insulator Bi2Se3 and insulating ferromagnet EuS were fabricated. Weak localization of the surface states was observed at the interface under the Curie temperature of EuS, as a direct evidence of the proximity effect. Using MBE with the RF cracker cell, high quality ultrathin Bi2Se3 films were successfully grown. Analysis of the magneto-resistance of those ultrathin samples measured at low temperature shows both the characteristic weak antilocalization from the surface states and the weak localization from the quantized bulk states, in good agreement with theoretical predictions. With our abilities to add various dopants during the deposition, and to deposit high quality thin films of different materials other than topological insulators, in both the MBE and PLD systems, we are excited to see the door to more interesting structures and fascinating physics opening in front of us.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Stanford University, Department of Applied Physics.
|Statement of responsibility
|Submitted to the Department of Applied Physics.
|Thesis (Ph.D.)--Stanford University, 2013.
- © 2013 by Li Zhang
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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