Observation of the Berreman Effect in Infrared Reflection-Absorption Spectra of Amorphous Titanium Oxide Thin Films Deposited on Aluminum

Trasferetti, B. C.; Davanzo, Celso U.; Cruz, Nilson Cristino da; Moraes, Márcio de

doi:10.1366/0003702001949933

Cited by 18 publications

(23 citation statements)

References 22 publications

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“…These integration values were correlated with the attached amount of CMC measured with the polyelectrolyte titration technique in a cubic model. The cubic model was chosen because it is predicted by theory (Tolstoy et al 2003).…”

Section: Irras Measurementsmentioning

confidence: 99%

“…al. 1985;Trasferetti et al 2000). This opens up the possibility of quantitative measurements of CMC attached to cellulosic fibers.…”

Section: Introductionmentioning

confidence: 96%

“…The first theoretical explanation of this effect was given by (Berreman 1969), who gave the effect its name. The Berreman effect was later explained within the quantum mechanical regime of Polaritons (Tolstoy et al 2003), where the thin film structure causes an additional oszillator, and thus an additional optical phonon band.…”

Section: Introductionmentioning

confidence: 99%

“…This gives for the p-spectrum a band at the TO frequency (as in the s-polarized case) and an additional band at the LO frequency m LO . Therefore, all the bands that only exist in the p-spectrum can be detected very well by subtracting the s-spectrum from the p-spectrum, which yields a very sensitive detection method for thin films on dielectric or metallic substrates (Tolstoy et al 2003).…”

Section: Introductionmentioning

confidence: 99%

“…This measurement was made with a pellet made from pure CMC, to find the TO and LO frequencies. The real part of the dielectric function, e 0 , has an inflection point at the TO frequency, while the imaginary part e 00 has a maximum (Tolstoy et al 2003). However, the problem of the measurement is the grain size of the CMC particles.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of CMC attachment onto cellulosic fibers by infrared spectroscopy

et al. 2009

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Infrared spectroscopy has been used to measure the amount of carboxymethyl cellulose (CMC) attached to cellulosic fibers. CMC was attached to an unbleached kraft pulp in aqueous conditions. Isotropic handsheets were then prepared and ATR spectroscopy was used to measure the intensity of the carboxyl vibration, which correlates to the amount of attached CMC that was determined using a wet chemical approach. The ATR method is rather time consuming as several measurement points on the sample have to be averaged, although it is still much faster than the wet chemical approach. Infrared reflection absorption spectroscopy (IRRAS) using polarized light was further used to measure the amount of attached CMC. In this method the intensity of an electromagnetic wave confined to the thin layer is used to correlate the spectroscopy to the amount of CMC on the fiber surface in the paper sample. The measurement time is shorter than with the ATR method. The proposed IRRAS method could be employed as a fast and reliable way to quantify adsorption of chemicals on pulp fibers.

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Section: Irras Measurementsmentioning

confidence: 99%

“…al. 1985;Trasferetti et al 2000). This opens up the possibility of quantitative measurements of CMC attached to cellulosic fibers.…”

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of CMC attachment onto cellulosic fibers by infrared spectroscopy

et al. 2009

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Interpretation of IR Spectra of Ultrathin Films

2003

Handbook of Infrared Spectroscopy of Ultrathin Films

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Generally speaking, IR spectral measurements of ultrathin films are undertaken to determine (i) the chemical identity of adsorbed species (including dissociation fragments); (ii) the geometric or structural arrangement (orientation) of these species and their positions with respect to the surface atoms of the substrate; (iii) their vibrational, rotational, and translational motion on the surface; (iv) the charge distribution and energy level structure of the valence electrons in both adsorbate and substrate; and (v) the effects of external perturbations, such as the electric and magnetic fields, photons, electrons, heating, and surface pressure on factors (i)-(iv) [1]. However, such information cannot be extracted directly from the IR spectra of ultrathin films due to the strong dependence of the shape and relative intensity of the bands on the geometry of the experiment, the optical properties of the substrate, the surroundings, the gradient of the optical properties at the film-substrate interface and in the film itself, as well as on the film thickness, and the particle size in the case of powder or islandlike supports. These effects and their physical background are discussed in Sections 3.1-3.5 and 3.9. In addition, there can be an intensity transfer between modes of coadsorbed species and a change in the band position with surface coverage. This effect is used for determining the mode of the surface filling and the degree of intermixing of different species at the surface (Section 3.6). If the film under study is located at the electrode-solution interface, the resulting spectrum is made up of contributions of all species in the path of radiation that are affected by the electrode potential, which further complicates the interpretation. Apart from technical means (Chapter 4), there exist analytical and mathematical approaches to resolve contributions of different species in such a complex spectrum (Sections 3.7 and 3.8). Another feature of the IR spectra of ultrathin films that is perhaps surprising and unexpected is their sensitivity to the volume fraction, shape, and orientation of inhomogeneities (e.g., pores or inclusions) in the film. Moreover, if the characteristic size of the 140

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Deposition of Barrier Layers for Thin Film Solar Cells Assisted by Bipolar Substrate Biasing

Häberle

Kopecki

Schulz

et al. 2009

Plasma Processes & Polymers

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For the development of diffusion and insulation barriers for thin film solar cells on unpolished steel with a rough surface as substrate, investigations of the shape of deposited SiOx layers in dependence on an applied substrate biasing are carried out. Si‐wafers with a well‐defined surface structure in the range of micrometre are used as ‘model’ substrate. As a result, the deposition in the indentations of this surface is much higher in the case of a biased substrate. To determine the influence of the bias on the molecular structure, first investigations of the deposited layer without an applied bias are performed with in situ Fourier Transform InfraRed (FTIR) spectroscopy. Hence the molecular composition of the films is monitored during the deposition. In these spectra the Berreman effect occurs and is analysed.

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Observation of the Berreman Effect in Infrared Reflection-Absorption Spectra of Amorphous Titanium Oxide Thin Films Deposited on Aluminum

Cited by 18 publications

References 22 publications

Analysis of CMC attachment onto cellulosic fibers by infrared spectroscopy

Analysis of CMC attachment onto cellulosic fibers by infrared spectroscopy

Interpretation of IR Spectra of Ultrathin Films

Deposition of Barrier Layers for Thin Film Solar Cells Assisted by Bipolar Substrate Biasing

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