| Metal nanoshells consist of a spherical dielectric core surrounded by a metallic shell. The fabrication of silver nanoshells is experimentally described and quantified using Mie scattering theory. These particles are used as surfaced enhanced Raman scattering (SERS) substrates at an excitation wavelength of 1.06 □m. This represents the first time silver particles in solution have been used as SERS substrates at this wavelength. Enhancement factors on the order of 1 x 106 are observed. It is also demonstrated that silver colloidal aggregates deposited on a large silica particle are sufficient to move the surface plasmon to the infrared for surface enhanced Raman spectroscopy. The measured enhancement factors were on the order of 4 x 105. The use of SnCl2 in functionalizing a silica surface as a precursor for metal nanoshell growth is explored along with theoretical calculations of the optical extinctions for nanoshells using different metals, such as copper, nickel, or platinum. |
