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January 7th, 2011
Defense: F. Chowdhury
UNIVERSITY OF UTAH
ELECTRICAL AND COMPUTER ENGINEERING DEPARTMENT
THESIS DEFENSE FOR THE DEGREE OF
MASTER OF SCIENCE
by
Faisal Chowdhury
Advisor: Massood Tabib-Azar
Surface Enhanced Raman Spectroscopy on Dielectrophoresis induced Diffusion Limited Aggregation of Gold Nanoparticles.
Wires formed by diffusion limited aggregation (DLA) induced by dielectrophoresis (DEP) of gold nanoparticles were investigated as an effective sample preparation method for surface enhanced Raman spectroscopy (SERS). Thymine was used as a test molecule and its SERS was measured to investigate the effectiveness of this technique that reproducibly resulted in x1E9 enhancement. It is known that molecules adsorbed near or at the surface of certain nanostructures produce strongly increased Raman signals and such phenomena is attributed to the concentration of electromagnetic (EM) optical fields at “hotspots” that usually occur at nanoscale junctions or clefts in metal nanostructures. Similarly, the enhancement obtained is attributed to the localized surface Plasmon’s of the gold nanoparticles and the formation of “hotspots” in DEP wires. There are other methods that reproducibly yield in excess of x1E8 enhancement in SERS using tunable lasers and very elaborate Raman spectroscopy. The results presented here are obtained using fixed laser excitation source at 785 nm and a simple spectrometer (5 cm-1 resolution).
Friday, January 7, 2011
10:00 a.m.
School of Computing Conference Room
3105 MEB
The public is invited