Quantitative analysis of the effect of disorder-induced mode coupling on infrared absorption in silica

Kirk, Charles T.

doi:10.1103/physrevb.38.1255

Cited by 663 publications

(540 citation statements)

References 29 publications

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“…The dielectric function of the oxide consists of three Lorentz-like harmonic oscillators modeling the optically active Si-O rocking and stretching vibrations. 45 The oxide produces very subtle effects in the M 33 spectra between 13 and 37 THz. The presence of the depletion layer is expressed as small offsets primarily in the MIR spectral region.…”

Section: Resultsmentioning

confidence: 99%

Variable-wavelength frequency-domain terahertz ellipsometry

Hofmann

Herzinger

Boosalis

et al. 2010

Review of Scientific Instruments

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We report an experimental setup for wavelength-tunable frequency-domain ellipsometric measurements in the terahertz spectral range from 0.2 to 1.5 THz employing a desktop-based backward wave oscillator source. The instrument allows for variable angles of incidence between 30°and 90°and operates in a polarizer-sample-rotating analyzer scheme. The backward wave oscillator source has a tunable base frequency of 107-177 GHz and is augmented with a set of Schottky diode frequency multipliers in order to extend the spectral range to 1.5 THz. We use an odd-bounce image rotation system in combination with a wire grid polarizer to prepare the input polarization state. A highly phosphorous-doped Si substrate serves as a first sample model system. We show that the ellipsometric data obtained with our novel terahertz ellipsometer can be well described within the classical Drude model, which at the same time is in perfect agreement with midinfrared ellipsometry data obtained from the same sample for comparison. The analysis of the terahertz ellipsometric data of a low phosphorous-doped n-type Si substrate demonstrates that ellipsometry in the terahertz spectral range allows the determination of free charge-carrier properties for electron concentrations as low as 8 ϫ 10 14 cm −3 .

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Section: Resultsmentioning

confidence: 99%

Variable-wavelength frequency-domain terahertz ellipsometry

Hofmann

Herzinger

Boosalis

et al. 2010

Review of Scientific Instruments

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“…2. To the best of our knowledge, the band at $1300 cm À1 has never been observed on silica films and crystals [2,7,8,[23][24][25][26]. In addition, the band is by about 250 cm À1 higher than that of Si-O-Mo stretching vibrations on SiO 2 =Moð112Þ [2].…”

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confidence: 90%

Growth and Structure of Crystalline Silica Sheet on Ru(0001)

et al. 2010

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Thin SiO 2 films were grown on a Ru(0001) single crystal and studied by photoelectron spectroscopy, infrared spectroscopy and scanning probe microscopy. The experimental results in combination with density functional theory calculations provide compelling evidence for the formation of crystalline, double-layer sheet silica weakly bound to a metal substrate. DOI: 10.1103/PhysRevLett.105.146104 PACS numbers: 68.35.Àp, 68.47.Gh, 68.55.Àa Silicon dioxide (SiO 2 ) plays a key role in many modern technologies and applications that range from insulating layers in integrated circuits to supports for metal and oxide clusters in catalysts. For better understanding of structureproperty relationships on silica-based materials, particularly of reduced dimensions, thin silica films grown on metal single crystal substrates are suggested as suitable model systems that allow the facile application of many ''surface science'' techniques. It has recently been shown that crystalline silica films and nanowires can be grown on Mo(112) [1][2][3][4][5]. The ultrathin film consists of a monolayer honeycomblike network of corner-sharing [SiO 4 ] tetrahedra, thus resulting in a SiO 2:5 stoichiometry of the film. The Si atoms in these films can be partly substituted by Al in the course of preparing metal supported aluminosilicate films [6], which is the first step towards experimental modeling of catalytic centers in zeolitelike materials. However, attempts to grow thicker silica films on the Mo substrates resulted in amorphous structures [7][8][9], most likely due to the formation of strong Si-O-Mo bonds at the interface that govern the growth mode [9]. Recently, the preparation of crystalline silica films on other supports such as Pd(100) [10] and Ni(111) [11] has been reported. However, the atomic structure of the films, film surface termination, and the nature of the silica-metal interface were not determined.In this Letter, we report on the preparation and the atomic structure of well-defined silica films on Ru(0001). The experimental results, obtained by photoelectron and vibrational spectroscopies and high-resolution scanning probe microscopy, are complemented by density functional theory calculations which together provide compelling evidence for the formation of a double-layer sheet silicate, with a SiO 2 stoichiometric composition, weakly bound to a metal support. The results open new perspectives for employing a ''surface science'' approach to understand the reactivity of silicate surfaces consisting of hydrophobic Si-O-Si bonds, such as those of microporous all-silica zeolites [12]. Also, these films can be used as model supports for catalytically active metal and oxide clusters [4,13].The experiments were performed in an ultrahigh vacuum chamber equipped with low energy electron diffraction (LEED) and Auger electron spectroscopy, x-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRAS), and scanning tunneling microscopy (STM). Atomically resolved atomic force microscopy (AFM) and STM image...

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“…We have collected the FTIR spectra on the various films, in order to examine the evolution of the so-called LO 4 -TO 4 doublet that is known to be indicative of the disorder within the SiO 2 matrix. 16 Figure 2 compares the corresponding FTIR spectra obtained at the Brewster incidence angle ͑65°͒ after being normalized on the LO 3 peak. One can observe that the intensity and structure of LO 4 -TO 4 doublet are slightly affected when T d increases from RT to 400°C.…”

Section: A Structural Analysesmentioning

confidence: 99%

Efficient energy transfer from Si-nanoclusters to Er ions in silica induced by substrate heating during deposition

Cueff

Labbé

Cardin

et al. 2010

Journal of Applied Physics

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Articles you may be interested inResonant structures based on amorphous silicon suboxide doped with Er 3 + with silicon nanoclusters for an efficient emission at 1550 nm J. Vac. Sci. Technol. B 27, L38 (2009) This study investigates the influence of the deposition temperature T d on the Si-mediated excitation of Er ions within silicon-rich silicon oxide layers obtained by magnetron cosputtering. For T d exceeding 200°C, an efficient indirect excitation of Er ions is observed for all as-deposited samples. The photoluminescence intensity improves gradually up to a maximum at T d = 600°C before decreasing for higher T d values. The effects of this "growth-induced annealing" are compared to those resulting from the same thermal budget used for the "classical" approach of postdeposition annealing performed after a room temperature deposition. It is demonstrated that the former approach is highly beneficial, not only in terms of saving time but also in the fourfold enhancement of the Er photoluminescence efficiency.

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Quantitative analysis of the effect of disorder-induced mode coupling on infrared absorption in silica

Cited by 663 publications

References 29 publications

Variable-wavelength frequency-domain terahertz ellipsometry

Variable-wavelength frequency-domain terahertz ellipsometry

Growth and Structure of Crystalline Silica Sheet on Ru(0001)

Efficient energy transfer from Si-nanoclusters to Er ions in silica induced by substrate heating during deposition

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