Title page for etd-0606116-103156


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URN etd-0606116-103156
Author Chun-Ying Fang
Author's Email Address No Public.
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Department Materials and Optoelectronic Science
Year 2015
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Condensation and crystallization upon pulsed laser ablation of AlN polycrystal in vacuum and tetraethyl orthosilicate
Date of Defense 2016-06-28
Page Count 78
Keyword
  • pulsed laser ablation
  • aluminum nitride
  • aluminum oxide
  • TEOS
  • spinel structure
  • Abstract This research is about pulsed laser ablation (PLA) of hexagonal wurtzite-type AlN polycrystal in vacuum and tetraethyl orthosilicate (TEOS) to form solidified particulates and nanocondensates for X-ray diffraction, electron microscopy and optical spectroscopic characterizations.
    The product produced in vacuum and accumulated on a C-coated collodion film (regardless of Q-switch or free run mode being adopted for PLA) turned out to be C-N doped γ-Al2O3-x and C-N-O doped fcc-type Al with characteristic optical luster, XPS spectrum and UV-visible absorbance. The spinel-type γ-Al2O3-x occurred as solidified particulate hardly with (hkl) facets. The fcc-type Al particulates and nanocondensates however have well-developed ~{111} vicinal surface for mutual coalescence as polycrystal with relic subgrain boundaries. A higher N fugacity by N2 gas purging under a specified flow rate during PLA of AlN in vacuum caused the formation of novel spinel-type C-O doped Al2N1-x besides the C-N-O doped fcc-Al. Such nonrefractory nanocondensates more or less with paracrystalline distribution of defect clusters tended to be parallel epitaxially coalesced into unity leaving abundant relic of the subgrains and dislocations.
    By contrast, the sample produced by PLA of AlN in TEOS consists of C-Si-H doped AlO1-x amorphous phase in the form of spherical particles ranging from 20 to 200 nm in diameter. Whereas PLA of metal Al in TEOS, caused additional C-Si-H doped γ-Al2O3-x nanocondensates with paracrystalline distribution of defect clusters and well-developed {111} and {100} surfaces for parallel-epitaxial coalescence as a spherical particle which became polysynthetic twinned and then amorphized upon electron irradiation for tens of minutes. The particles produced by PLA of AlN and Al in TEOS showed different UV-visible absorbances.
    Advisory Committee
  • C.N. Huang - chair
  • Shuei-Yuan Chen - co-chair
  • P. Shen - advisor
  • Files
  • etd-0606116-103156.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2016-07-06

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