Dissertation
Photoelectron spectroscopy studies on group IV semiconductor clusters and novel binary clusters
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2007
DOI:
https://doi.org/10.7273/000005755
Abstract
Clusters consisting of a few to a few hundred atoms (~ 2 nm) cover a critical size range, in which the finite-sized systems evolve from molecular-like species to nanoparticles. Photoelectron spectroscopy of size-selected cluster anions in gas phase is a powerful technique to investigate their electronic structure and follow the evolution from discrete molecular features to bulk band structures. Advances in our laboratory to improve the photoelectron energy resolution and to control cluster temperatures have enabled us to obtain well-resolved photoelectron spectra for a wide range of gas-phase
atomic clusters. This dissertation mainly focuses on studies of group IV semiconductor (Si, Ge, Sn) clusters. Several binary cluster systems, such as hydrogenated aluminum clusters and alkali and coinage metal alloy clusters were also investigated. We have confirmed a prolate-to-spherical structural transition with the increase of size for silicon clusters. A semiconductor-to-metal transition was elucidated for tin clusters as a function of size. More importantly, we discovered a stable 12-atom tin cluster Sn12 2-, which has a
highly symmetric icosahedral structure and is named stannashperene for its high stability, high symmetry and π-bonding characters. This icosahedral cage has a size comparable to that of C60 and can be considered as an inorganic analog of the fullerenes. Subsequently, we have synthesized a series of endohedral cage clusters M@Sn12 2-, where M is a transition metal atom. The doped atom in M@Sn12 - keeps its quasi-atomic nature with large magnetic moments. These endohedral cage clusters might thus be viewed as “superatoms”, yielding a rich class of new building blocks for cluster-assembled materials with tunable magnetic, electronic, and chemical properties.
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Details
- Title
- Photoelectron spectroscopy studies on group IV semiconductor clusters and novel binary clusters
- Creators
- Lifeng Cui
- Contributors
- Lai-Sheng Wang (Chair)J Thomas Dickinson (Committee Member) - Washington State University, Department of Physics and AstronomyAlexander Dequan Li (Committee Member) - Washington State University, Department of Chemistry
- Awarding Institution
- Washington State University
- Academic Unit
- Materials Science and Engineering Program
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 272
- Identifiers
- 99901054759001842
- Language
- English
- Resource Type
- Dissertation