Characterization of epitaxial silicene on the Ag(111) surface with synchrotron-based soft X-ray spectroscopy
The eventual incorporation of two-dimensional materials into electronic devices will require an intimate understanding of their electronic properties, as well as how these properties are affected by the material's local environment. The specific focus of this thesis is on silicene, the silicon-based analogue to the prototypical 2D material graphene. In particular, the studies contained within this thesis aim to elucidate the electronic properties of silicene monolayers and multilayers grown on the Ag(111) surface through combination of ab initio density functional theory calculations and synchrotron-based soft X-ray spectroscopy. The first study explores the electronic interaction between epitaxial silicene monolayers and their Ag(111) substrate, finding evidence for significant hybridization between them that confers a metallic electronic structure upon the silicene. The second examines the effects of oxidation on the electronic and structural characteristics of epitaxial silicene monolayers on Ag(111), refuting the notion of a bandgap opening at low oxygen coverage and showing that the structure is inherently unstable at high oxygen coverage. Finally, silicene growth beyond a monolayer is studied, and strong evidence for the instability of multilayer silicene on Ag(111) is presented. In addition, this thesis contains a review of the history, properties and potential applications of a variety of two-dimensional materials, focusing on the qualities that will impact their application to electronic devices. It also discusses the techniques involved in producing, structurally characterizing, and predicting and measuring the electronic properties of epitaxial silicene on Ag(111).
DegreeDoctor of Philosophy (Ph.D.)
DepartmentPhysics and Engineering Physics
CommitteeSham, Tsun-Kong; Xiao, Chijin; Tse, John S.; Kelly, Timothy L.
Copyright DateMay 2016
Density Functional Theory