Atomic Structures of Metallic and Semiconducting Nanocrystals by Coherent Electron Diffraction

The third application of the single-particle diffraction technique is to measure the temperature-dependent structures of individual nanocrystals. Again, Au nanocrystals were studied for this experiment. Experimentally, we recorded diffraction patterns from the same Au nanocrystals at different temperatures. From the diffraction data, we found that the coefficient of thermal expansion (CTE) of TiO2-supported Au nanocrystals is size dependent: the CTE is positive for nanocrystals larger than 7 nanometers in diameter and negative for the smaller nanocrystals. From the diffraction intensity, we also extracted through modeling the mean square displacement of the surface atoms of the Au nanocrystals as a function of temperature, and found that surface atoms have a significantly larger vibration amplitude than the interior atoms.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science and Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Huang, Weijie

Contributors dc:contributor

• Zuo, Jian-Min

• Engineering, Materials Science

Language dc:language

eng

Identifier

(MiAaPQ)AAI3314793

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/82819