Raman study on surface layers and thin films by using total reflection experiments

Hölzer, W.; Schröter, O.; Richter, A.

doi:10.1016/0022-2860(90)80366-r

Cited by 8 publications

(6 citation statements)

References 10 publications

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“…This technique originated from the seminal work by Ikeshoji et al (1973) on the glass/carbon disulfide system and developed by Iwamoto et al and Hölzer et al. in their studies on polymer-coated surfaces . Here, the type of dielectric materials is limited by some specific requirements.…”

Section: Introductionmentioning

confidence: 99%

“…This technique originated from the seminal work by Ikeshoji et al 15 (1973) on the glass/carbon disulfide system and developed by Iwamoto et al 16 and Holzer et al in their studies on polymercoated surfaces. 17 Here, the type of dielectric materials is limited by some specific requirements. For example, dielectrics must exhibit a higher refractive index than the surrounding media (including the analyte), to meet conditions for total internal reflection above the critical angle and propagate the resulting evanescent wave through the adsorbed analytes.…”

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confidence: 99%

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Enhanced Raman Scattering with Dielectrics

2016

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Dielectrics represent a new frontier for surface-enhanced Raman scattering. They can serve as either a complement or an alternative to conventional, metal-based SERS, offering key advantages in terms of low invasiveness, reproducibility, versatility, and recyclability. In comparison to metals, dielectric systems and, in particular, semiconductors are characterized by a much greater variety of parameters and properties that can be tailored to achieve enhanced Raman scattering or related effects. Light-trapping and subwavelength-focusing capabilities, morphology-dependent resonances, control of band gap and stoichiometry, size-dependent plasmons and excitons, and charge transfer from semiconductors to molecules and vice versa are a few examples of the manifold opportunities associated with the use of semiconductors as SERS-active materials. This review provides a broad analysis of SERS with dielectrics, encompassing different optical phenomena at the basis of the Raman scattering enhancement and introducing future challenges for light harvesting, vibrational spectroscopy, imaging, and sensing.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Enhanced Raman Scattering with Dielectrics

2016

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“…Total internal reflection (TIR) Raman spectroscopy measures chemically specific information from an analyte located within a hundred nanometers to a few micrometers from an interface. − Under TIR, the illuminating laser light is directed onto a prism/analyte interface at an incident angle higher than the critical angle (Figure a). Under these conditions, the Raman signal is confined to the interface as a result of the generated evanescent wave’s limited penetration into the sample.…”

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confidence: 99%

Plasmon Waveguide Resonance Raman Spectroscopy

2012

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Raman spectra were collected from a 1.25 M aqueous pyridine solution, 100-nm polystyrene film or a trimethyl(phenyl)silane monolayer at a plasmon waveguide interface under total internal reflection (TIR). The plasmon waveguide resonance (PWR) interface consisted of a sapphire prism/49 to 50 nm Au/548 to 630 nm SiO(2) and a monolayer, thin film or aqueous analyte. The Raman peak area as a function of incident angle was measured using a 785-nm excitation wavelength, and was compared to the Raman peak area obtained at a sapphire or sapphire/50 nm Au interface. In contrast to measurements at a bare sapphire prism, increased surface sensitivity and signal were obtained from the PWR interface. In contrast to measurements at a bare Au film where only p-polarized incident light generates an enhanced interfacial electric field, plasmon waveguide interfaces enable excitation with orthogonal polarizations using s- or p-polarized incident light. The Raman scatter from a monolayer was recorded at the PWR interface with a signal-to-noise ratio of 5.6 when averaging 3 accumulations with 3 min acquisition times using nonresonant excitation, whereas no signal was recorded from a monolayer at the sapphire interface. The reflected light from the interface enabled the identification of the incident angle where the maximum Raman scatter was produced, and the Raman signal generated at the plasmon waveguide interface was modeled by the enhanced interfacial mean square electric field relative to the incident field. In comparison to the techniques on which this work was based (i.e., PWR spectroscopy, TIR Raman spectroscopy at the prism interface, and surface plasmon resonance (SPR) Raman spectroscopy at the prism/Au interface), chemical specificity was added to PWR spectroscopy, a signal enhancement mechanism was introduced for TIR Raman spectroscopy, and polarization control of the interfacial electric field was added to SPR Raman spectroscopy.

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“…At angles above the critical angle, total internal reflection conditions occur, and a surface-sensitive evanescent wave is generated in the sample. TIR-Raman spectroscopy has been useful in studying films, surfactants, plants, and adsorbates at various interfaces. − As with conventional Raman spectroscopy, TIR Raman spectroscopy has the benefits of being noninvasive, fast, and requiring minimal sample preparation provided the sample can be optically coupled to the prism. For conditions where the same amount of analyte is probed, the TIR Raman geometry acts as a signal enhancement mechanism, and excellent signal-to-noise ratio spectra are possible for thin films using several second acquisition times.…”

Section: Introductionmentioning

confidence: 99%

Scanning Angle Plasmon Waveguide Resonance Raman Spectroscopy for the Analysis of Thin Polystyrene Films

et al. 2012

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Scanning angle (SA) Raman spectroscopy was used to characterize thin polymer films at a sapphire/50 nm gold film/polystyrene/air interface. When the polymer thickness is greater than ∼260 nm, this interface behaves as a plasmon waveguide; Raman scatter is greatly enhanced with both p-and s-polarized excitation compared to an interface without the gold film. In this study, the reflected light intensities from the interface and Raman spectra were collected as a function of incident angle for three samples with different polystyrene thicknesses. The Raman peak areas were well modeled with the calculated mean-square electric field (MSEF) integrated over the polymer film at varying incident angles. A 412 nm polystyrene plasmon waveguide generated 3.34× the Raman signal at 40.52° (the plasmon waveguide resonance angle) compared to the signal measured at 70.4° (the surface plasmon resonance angle). None of the studied polystyrene plasmon waveguides produced detectable Raman scatter using a 180° backscatter collection geometry, demonstrating the sensitivity of the SA Raman technique. The data highlight the ability to measure polymer thickness, chemical content, and, when combined with calculations of MSEF as a function of distance from the interface, details of polymer structure and order. The SA Raman spectroscopy thickness measurements agreed with those obtained from optical interferometery with an average difference of 2.6%. This technique has the potential to impact the rapidly developing technologies utilizing metal/polymer films for energy storage and electronic devices.

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Raman study on surface layers and thin films by using total reflection experiments

Cited by 8 publications

References 10 publications

Enhanced Raman Scattering with Dielectrics

Enhanced Raman Scattering with Dielectrics

Plasmon Waveguide Resonance Raman Spectroscopy

Scanning Angle Plasmon Waveguide Resonance Raman Spectroscopy for the Analysis of Thin Polystyrene Films

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