Fabrication of optically active nanostructures by chemical methods
Moran, Cristin Erin
Halas, Naomi J.
Doctor of Philosophy
A new method of fabricating long-range, planar arrays of discrete, submicron metal structures on glass or SiO2/Si surfaces has been developed without the use of resist masks or chemical etching. The approach combines microcontact printing and electroless plating for the controlled deposition of islands or lines of gold or silver. The metallic structures are varied in size, separation and shape by using a variety of commercial diffraction gratings to mold the polydimethylsiloxane (PDMS) elastomer stamps. An assortment of distinct geometrical patterns have been fabricated and imaged on a range of length scales using scanning probe, scanning electron, and optical microscopies. Additionally, the same chemical techniques can be used to pattern surfaces with biomolecules and ordered arrays of metal nanoshells. These arrays of metal nanostructures support surface plasmon propagation and also show plasmon-plasmon interactions dependent on the geometry of the metal features. These structures were used to investigate the effects of molecular functionalization on the excitation and propagation properties of the surface plasmons that are supported by this geometry. Distinct variations in the dispersion and energy gaps of surface plasmons on these structures due to chemical functionalization of the metal structures is observed. A second type of optically active structure, rare-earth doped silica particles, has been synthesized using wet chemistry. The polydispersity of the particles can be controlled by changing the concentration of dopant salt. These particles may be useful for microlaser or display technologies.
Physical chemistry; Chemical engineering; Condensed matter physics; Engineering; Materials science