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Using nylon-6 and polystyrene as prototypical materials with organic functional groups, we have demonstrated that for silicon or gold substrates, features due to the molecular vibrations can be seen in the ellipsometric spectra for films as thin as 50 Å with signal-to-noise ratios ranging from 2 to 10. It is expected that with some additional optimization, this could be improved by a factor of 2 to 4. For films on a gold substrate, due to the high reflectivity, one would expect to be able to see these features for 10 Å or thinner. For films on the glass substrate (or any other substrate that has an index of refraction near that of the film in the nonabsorbing region), IR ellipsometry provides thickness information that cannot readily be obtained from traditional ellipsometry. For all of the substrates, IR ellipsometry provides molecular structure information.

Electrodeposition of gold mesoparticles on anodized and chemically etched aluminum/copper films deposited on silicon wafers proceeds by instantaneous nucleation and with no diffusion limitations. Both of these phenomena favor the formation of relatively monodispersed gold particles. Under the reported electrodeposition conditions, the relative standard deviation of the particle diameter is 25%. The particle coverage is 7 x 10(8) particles cm(-2). The mean particle diameter varies as a function of electrodeposition time in the range of 40-80 nm. Optical constants of gold mesoparticles are resolved by spectroscopic ellipsometry. A two-layer optical model is constructed to determine both extinction coefficients and refractive indexes of gold mesoparticles as a function of the mean particle diameter. The absorption peak, associated with surface plasmons, is modeled with two Lorentz oscillators. Absorption peak maximums shift from 610 to 675 nm as the mean particle diameter increases from 42 to 74 nm. Electrodeposition of gold particles on technologically relevant substrates, such as aluminum/copper films, is expected to increase the utility of gold particles and facilitate their incorporation in nanostructured materials and a variety of electronic and optical devices.