Doctoral Dissertations

Wan Shou

Abstract

"The transport and interfacial phenomena in laser melting and crystallization of silicon in micro-/nano-scale confinement lacks sufficient understanding. Uncovering the underlying mechanisms, and hence harness the melting and crystallization processes can help the formation of controllable single-crystal structures or patterns. In this dissertation, a molecular dynamics (MD) simulation was conducted to calculate the interfacial free energy of the silicon system in contact with flat and structured walls. Then the calculated interfacial energies were employed to predict the nucleation mechanisms in a slab of liquid silicon confined by two walls and compared with MD simulation results. Further, in combination with a macroscopic model, it was concluded that for a given domain size, longer laser pulse increases the probability of forming single crystals. It was also suggested that for micro size Si domains, a continuous wave (CW) laser operated in a scanning mode can possibly generate single crystal structure.

To examine the theoretical predication, CW laser crystallization of Si nanoparticles was conducted. A non-vacuum printing process, aerosol printing, was adopted in this dissertation, which enabled us to prepare Si film and lines with a cost-effective manner. Followed with pressing, the Si nanoparticles were densified and planarized. Then, the nanoparticles were laser melted and crystallized in the confined domain. It was found that the morphology and crystalline structure can be modulated from poly-crystal line to single-crystal islands through tuning the gap of confinement"--Abstract, page iv.

Advisor(s)

Pan, Heng

Committee Member(s)

Tsai, Hai-Lung
Liou, Frank W.
Leu, M. C. (Ming-Chuan)
Newkirk, Joseph William

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Sponsor(s)

National Science Foundation (U.S.)
Missouri University of Science and Technology. Intelligent System Center

Comments

This work was supported by the National Science Foundation under Grant No. 1363313. This work was also partially supported by ORAU Ralph E. Powe Junior Faculty Enhancement Award. This research was also partially supported Intelligent System Center (ISC) and Material Research Center (MRC) at Missouri University of Science and Technology.

Research Center/Lab(s)

Intelligent Systems Center

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2018

Journal article titles appearing in thesis/dissertation

  • Silicon-wall interfacial free energies via thermodynamics integration
  • Transport and interfacial phenomena in nanoscale confined laser crystallization
  • Direct printing single-crystal Si islands by microscale nanoparticle printing and confined laser melting and crystallization

Pagination

xi, 91 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2018 Wan Shou, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11725

Electronic OCLC #

1164805369

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