Low temperature scanning tunneling microscope study of metallic thin films and nanostructures on the semiconductor substrates

Repository

Low temperature scanning tunneling microscope study of metallic thin films and nanostructures on the semiconductor substrates

Show simple record

dc.contributor.advisor Shih, Chih-kang
dc.creator Qin, Shengyong, 1980-
dc.date.accessioned 2012-10-10T20:45:11Z
dc.date.available 2012-10-10T20:45:11Z
dc.date.created 2008-12
dc.date.issued 2012-10-10
dc.identifier.uri http://hdl.handle.net/2152/18267
dc.description.abstract Many properties of the thin films are different from the bulk value and in many cases, depend dramatically on the film thickness. In the metallic ultra-thin films epitaxially grown on the semiconductor substrate, the conduction electrons are confined by the vacuum and metal-semiconductor interface. When the film thickness is comparable to the electron Fermi wavelength, this confinement will produce discrete energy levels known as quantum well states (QWS), which dramatically modify the electronic structures of the thin film and this is called quantum size effect (QSE). QSE will have a profound effect on a lot of physical properties of the thin films. Among various systems exhibiting QSE, Pb/Si (111) is the most widely studied one and exhibits the richest phenomena in QSE. In this study, a home made low temperature Scanning Tunneling Microscopy/Spectroscopy (LT-STM/S) was used to study the superconductivities of the Pb thin films. Quantum oscillations of the superconductivity have been observed for the films down to 4 monolayer and the oscillation amplitude increases as the film gets thinner. To resolve the discrepancies between the superconductivities measured with ex-situ transport and in-situ STS. We also studied the influence of Au overlay on the Pb thin films with LT-STM/S, and found out the deposition of Au on Pb dramatically roughened the Pb films. Finally, we successfully grew large scale near perfect 2ML Pb films. There are two types of films which exhibit different Moiré patterns. LT-STS studies revealed there is big difference in the superconductivity Tc of these two films, both of which decreased dramatically from that of the 4ML film.
dc.format.medium electronic
dc.language.iso eng
dc.rights Copyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.
dc.subject.lcsh Thin films
dc.subject.lcsh Metallic films
dc.subject.lcsh Superconductivity
dc.subject.lcsh Superconductors
dc.subject.lcsh Scanning tunneling microscopy
dc.subject.lcsh Nanostructures--Magnetic properties
dc.title Low temperature scanning tunneling microscope study of metallic thin films and nanostructures on the semiconductor substrates
dc.description.department Physics
dc.type.genre Thesis
dc.type.material text
thesis.degree.department Physics
thesis.degree.discipline Physics
thesis.degree.grantor The University of Texas at Austin
thesis.degree.level Doctoral
thesis.degree.name Doctor of Philosophy

Files in this work

Download File: qins17137.pdf
Size: 3.461Mb
Format: application/pdf

This work appears in the following Collection(s)

Show simple record


Advanced Search

Browse

My Account

Statistics

Information