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Optical Spectroscopy of Nanostructured Materials

Hartschuh, Ryan D.
http://rave.ohiolink.edu/etdc/view?acc_num=akron1195016254

Abstract Details

2007, Doctor of Philosophy, University of Akron, Polymer Science.
Significant interest in nanotechnology is stimulated by the fact that materials exhibit qualitative changes of properties when their dimensions approach nanometer scales. Quantization of electronic, optical, and acoustic energies with nanoscale dimensions provides exciting, novel functions and opportunities, with interests spanning from electronics and photonics to biology. Characterizing the behavior of nanoscale materials is critical for the full utilization of such novel properties, but metrology for nanostructures is not yet well developed. In particular, mechanical properties of nanoscale particles or features are critical to the manipulation and stability of individual elements, yet changes in mechanical and thermodynamic properties in nanostructured materials create complications in fabrication. This thesis involves the application of Brillouin light scattering to quantify and utilize confinement induced vibrational spectra to understand phononics and elastic properties of nanostructured materials. Measurement and proper interpretation of acoustic waves in polymeric, inorganic, and biological nanostructures provides information about elastic properties and self-assembly. Brillouin light scattering was used to study the vibrational spectra of two-dimensionally confined photoresist and silicon oxide nanolines and three-dimensionally confined poly(methyl methacrylate) spheres and spherical-like viruses. These applications extend the capabilities of Brillouin from characterization of thin films and well-defined spheres to more complex structures. Acoustic waves propagating along the polymeric and silicon oxide lines allowed determination of modulus and its anisotropy. An unexpected acoustic mode was identified in the spectra from nanolines that provided a means to measure mechanical anisotropy. In polymeric lines as narrow as 88nm, neither a change in elastic properties relative to bulk elastic values nor anisotropy in elastic constants was observed. The acoustic waves propagating within polymeric and silicon oxide nanolines were mostly similar, but differed somewhat due to the ratio of elasticities between the lines and the substrate. More localized vibrations were observed in the photoresist lines than in the silicon oxide lines, both of which rested on a silicon oxide substrate. Analysis of the Brillouin spectra from Wiseana Iridoviruses (WIV) revealed strong mechanical coupling between close-packed viruses, unlike the behavior of polymeric colloidal particles. In contrast to traditional model assumptions, Brillouin spectra indicated that their DNA core, rather than their protein shell, dominated the elastic properties of WIV.
Alexei Sokolov (Advisor)
222 p.
Brillouin light scattering; acoustic surface waves; mechanical properties of nanostructures; mechanical properties of viruses; mechanical properties of photoresist features; mechanical properties of thin films; optical characterization

Recommended Citations

Citations

  • Hartschuh, R. D. (2007). Optical Spectroscopy of Nanostructured Materials [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1195016254

    APA Style (7th edition)

  • Hartschuh, Ryan. Optical Spectroscopy of Nanostructured Materials. 2007. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1195016254.

    MLA Style (8th edition)

  • Hartschuh, Ryan. "Optical Spectroscopy of Nanostructured Materials." Doctoral dissertation, University of Akron, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1195016254

    Chicago Manual of Style (17th edition)

akron1195016254
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© 2007, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.