Conductive oxide thin films: Model systems for understanding and controlling surface plasmon resonance Attenuated-total-reflection predictions to surface-plasmon resonance in a layered structure J. Appl. Phys. 98, 053708 (2005); 10.1063/1.1991977 High resolution surface plasmon resonance spectroscopy Rev. Sci. Instrum. 70, 4656 (1999); 10.1063/1.1150128Detection of surface-plasmon evanescent fields using a metallic probe tip covered with fluorescence Rev.

Surface plasmon resonance (SPR) measurements provide a highly sensitive means for detecting biomolecular interactions in a label-free manner. Numerous studies of biomolecular interactions have been performed with fixed-angle SPR imaging (SPRi) on surfaces patterned with a variety of biomolecules such as DNA, RNA, proteins, and peptides. 1 Arrays increase the information obtainable in a single experiment as multiple reactions can be monitored in parallel.A current and significant limitation of SPR is that the substrate must be a metal thin film. A number of metal thin films are capable of supporting surface plasmons in the near-infrared and visible regions of the electromagnetic spectrum. 2,3 Gold surfaces have been the substrate of choice for SPR measurements for two reasons: gold is relatively stable in the aqueous environments needed for monitoring biomolecular interactions and a versatile chemistry based on the attachment of sulfur-containing ligands to the gold surface has been developed and wellcharacterized. The readily formed gold-sulfur bond enables the direct attachment of ligands to the gold surface 4 as well as attachment via an intermediate self-assembled monolayer (SAM). 5-7 This gold-thiol chemistry has made possible the routine analysis of aqueous binding processes to immobilized molecules at near-neutral pH values and moderate temperatures. The susceptibility of the gold-sulfur bond to oxidation and photodecomposition has prevented SPR sensing from finding utility in areas such as on-surface combinatorial chemistry (due to the harsh chemical conditions employed) and photolithography (due to the adverse effects of ultraviolet radiation on the gold-sulfur bond). 8Here we describe the development of a lamellar structure in which a thin layer of amorphous carbon is deposited onto a surface plasmon-active gold thin film (Figure 1a). Carbon-based surfaces are readily modified with biomolecules of interest using a well-developed and robust chemistry, based upon the attachment of alkene-containing molecules to the substrate through the UV light-mediated formation of carbon-carbon bonds. 9 Recently, a similar lamellar structure utilizing a thin silicate overlayer was used to fabricate and monitor supported bilayer membranes with SPR. 10 E-mail: smith@chem.wisc.edu. Arrays prepared on functionalized carbon-based substrates such as diamond thin films, 11,12 glassy carbon, 12 and amorphous carbon thin films 13 have superior stability to analogous arrays prepared on functionalized glass, silicon, and gold substrates. Amorphous carbon is of particular interest as it can be deposited at room temperature, allowing it to be integrated with other materials 14 such as quartz crystal microbalances, 13 electrodes, 15 and metal thin films without perturbing their structure. The utility of a multilayered substrate containing a metal thin film and an amorphous carbon overlayer is shown here by their use for in situ synthesis of oligonucleotide arrays, which are then employed in the analysis of biomolecule binding proces...

The sections in this article are Introduction to Polarization‐Modulation Reflection–Absorption Spectroscopy Experimental Considerations for the PM ‐ IRRAS Measurement Experimental Setup The PEM The PM ‐ IRRAS Measurement PM ‐ IRRAS Spectral Normalization Examples and Applications of PM ‐ IRRAS Measurement Metal Surfaces – Ex Situ Self‐Assembled Monolayers in the CH Stretching Region SAMs in the Fingerprint Region Metal Surfaces – Liquid Phase In Situ Structural Studies of SAMs Electrochemical Studies Metal Surfaces – Gas Phase In Situ Corrosion Studies on Copper Carbon Monoxide on Co (0001) Organic Vapors on Silicon Dioxide Nanoparticle Thin Films on Gold Air/Water Interface Summary

The gold-sulfur (Au-S) and silver-sulfur (Ag-S) bonds are integral to the surface modification of metal films with alkanethiol monolayers. Although the metal-sulfur bond can be characterized with surface-enhanced Raman spectroscopy (SERS) at roughened metal films, some applications require or perform better when using a smooth metal surface, which is not suitable for SERS signal enhancement. Directional-surface-plasmon-coupled Raman scattering (directional Raman scattering) is an approach to measure metal-sulfur bonds on smooth metal films with sub-monolayer sensitivity. The metal-sulfur bonds formed from a benzenethiol monolayer on smooth planar gold or silver films are observed in the directional Raman scattering spectra between 240 and 270 cm À1 ; the signal-to-noise ratio of the Au-S Raman peak is 60. Importantly, the directional Raman scattering signal measured with smooth metal surfaces can be simply modeled and easily compared across many samples. Directional Raman scattering can also be measured at roughened metal films, which makes it applicable for many analyses.