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  • 1
    Electronic Resource
    Electronic Resource
    The aluminum–polyimide interface: An electron-induced vibrational spectroscopy approach (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 3353-3362 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Clean polyimide films spin-coated onto gold substrate have been fully characterized by high resolution electron energy loss spectroscopy (HREELS): 19 electron-induced vibrational bands could be resolved and assigned by comparison with IR spectroscopy. The attribution of these peaks constitutes a firm and necessary basis for the detailed study of the incipient interface formation with aluminum at room temperature. The metal being evaporated at a low rate from a Knudsen effusion cell, its equivalent coverage on the polymer could be monitored very efficiently and allowed a clear distinction between three reaction steps: (i) at an Al coverage below 4×1014 Al atom/cm2, the aluminum atoms interact only with the C–O carbonyl in the polymer to form a C–O–metal complex; (ii) between 4 and 10×1014 atom/cm2, no further Al "reaction'' occurs, but the appearance of new CH and OH stretching bands is attributed to bond breaking in the polymer and diffusion of the residues towards the surface; (iii) after further metal evaporation, all the peaks reduce in intensity and the observation of a ν(Al–O) [or ν(Al–C) band] testifies the formation of an aluminum oxide (or carbide) at the surface. Although no dedicated theory can be invoked up to now for the interpretation of HREELS data collected with different electron impact energies and under different scattering geometries, the spectra measured from polyimide before and after aluminum condensation are consistent with a modification of the geometry of the polymer monomeric unit after bonding with the metallic atoms. The metallized polymer surface appears with an equal statistical spatial distribution of all the chemical groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453930
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  • 2
    Electronic Resource
    Electronic Resource
    Pumping picosecond optical parametric oscillators by a pulsed Nd:YAG laser mode locked using a nonlinear mirror (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 1945-1947 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the performances of the mode locking of a flash-lamp-pumped Nd:YAG laser using a frequency-doubling nonlinear mirror combined with a two-photon absorber. Pulse lengths from 12 to 8 ps are generated. We show that the flat shape of the pulse-train envelope generated by the oscillator is adapted for the synchronous pumping of optical parametric oscillators and we demonstrate the efficient generation of an infrared beam tunable from 3800 to 1100 cm−1 with bandwidth of 2 cm−1 in one single conversion stage in LiNbO3 or AgGaS2. The "all-solid-state" laser system enables surface sum-frequency generation spectroscopy to be performed with high sensitivity and high resolution. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1405433
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  • 3
    Electronic Resource
    Electronic Resource
    All-solid-state 12 ps actively passively mode-locked pulsed Nd:YAG laser using a nonlinear mirror (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 3066-3068 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Efficient mode locking of a flash-lamp-pumped Nd:YAG laser at 1.064 μm is achieved by combining the passive–positive feedback of a frequency doubling nonlinear mirror (FDNLM) and the passive–negative feedback of a GaAs platelet. the FDNLM consists of a BBO crystal and of a dichroïc mirror. Pulse durations as short as 12 ps are obtained. Temporal evolution of pulse duration in the pulse train is presented and discussed. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125232
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  • 4
    Electronic Resource
    Electronic Resource
    Hydrocarbon reaction with HF-cleaned Si(100) and effects on metal-oxide-semiconductor device quality (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 108-110 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The surface reactivity of hydrogen-passivated, HF-cleaned Si(100) towards hydrocarbon adsorption is examined by surface analysis; most hydrocarbons adsorb on the surface. Dangling bonds formed during thermal processing react with fragmented organic molecules forming SiC. Metal-oxide-semiconductor devices fabricated on contaminated surfaces are degraded, with the degree of degradation depending on the nature of the contaminant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.105560
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  • 5
    Electronic Resource
    Electronic Resource
    Surface analysis of polyethylene and hexatriacontane by high resolution electron energy loss spectroscopy (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 6452-6457 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Surfaces of polyethylene and n-hexatriacontane were for the first time studied by high resolution electron energy loss spectroscopy (HREELS). The vibrational band energies and intensities were recorded and compared to transmission infrared data. The attribution of most of the bands to methyl, methylene, and C–C vibrations is straightforward; but some of the bands remain unassigned. The intensities of the methyl associated electron energy losses are greatly enhanced. This confirms the extreme surface sensitivity of the spectroscopy and is consistent with a C–C skeleton preferentially oriented perpendicular to the surface. Measured cross section data vs electron impact energy (E0) show that while a dipolar-type interaction mechanism is dominating some regions of the cross-section curve, other resonance scattering may contribute significantly for low and high E0. This cross-section curve shows also that the polymer surfaces are to be considered as a "condensed gas,'' with weak intermolecular interaction, instead of a real solid state material with collective (phonon) vibrational excitations. No evidence of radiation damage could be found in the vibrational spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450852
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  • 6
    Electronic Resource
    Electronic Resource
    C60 growth on Si(100), GaSe(0001) and GeS(001) (1993)
    Springer
    Applied physics 56 (1993), S. 175-183 
    Details
    ISSN: 1432-0630
    Keywords: 68.55.−a ; 73.60.−n ; 79.20.Kz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract C60 films have been grown in ultra high vacuum on various crystalline substrates and the structure of the films has been investigated by low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The C60 films form randomly oriented nanocrystals on Si(100), mesoscopic polycrystals on GaSe(0001) and microscopic single crystals on GeS(001). The vibrational structure of the C60/substrate interfaces is analyzed in detail by HREELS carried out in the dipole and impact scattering regimes. It is shown that the epitaxy of C60 on GeS(001) is induced by the weak van der Waals bonding and the peculiar corrugation of the substrate surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539471
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  • 7
    Electronic Resource
    Electronic Resource
    AES and HREELS studies of the Cu/MgO(100) interface (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 16 (1990), S. 446-451 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: We have studied the formation of the Cu/MgO interface with Auger electron spectroscopy and high-resolution electron energy-loss spectroscopy (HREELS). Copper overlayers ranging in thickness from 1 to 20 Å were formed on an MgO single- crystal substrate by evaporation from a Knudsen effusion cell. Direct Auger spectra for the O KLL, Cu LMM and Mg KLL lines were collected. The evolution of the Auger peak intensities shows that the copper initially forms a complete monolayer, followed by island formation (i.e. Stransky-Krastanov growth). Low energy electron diffraction patterns recorded after Cu deposition confirmed the ordering of the first monolayer.A significant decrease in energy of the surface MgO phonon peak was observed by HREELS following deposition of 20 Å of copper. Simultaneously with this shift of the phonon energy, we observed a decrease of the intensity ratio of the phonon-loss and elastic peaks. These results have been interpreted using the dielectric theory. Theoretical spectra of MgO covered by a layer of Cu2O obtained by using dielectric constants taken from the literature were able to reproduce qualitatively the decreases in energy and intensity of the phonon-loss peak with increasing copper thickness.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740160192
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  • 8
    Electronic Resource
    Electronic Resource
    Analysis of semiconductors and insulators by high-resolution electron energy loss spectroscopy - prospects for quantificationInvited paper presented at the Quantitative Surface Analysis (QSA-5) Conference, London, 15-18 November 1988. (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 15 (1990), S. 189-205 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: High-resolution electron energy loss spectroscopy (HREELS) is now widely known and recognized for its very significant contributions to the characterization of molecules adsorbed on well-defined surfaces: many chemical surface reactions were understood successfully (adsorption sites, reaction scheme, time-resolved experiments) through the analysis of electron-induced vibrational spectra. Semiconductors and insulators form other classes of materials that contribute to vibrational spectra by intrinsic vibrations: compound semiconductors, and insulators present acoustic and optical phonons, i.e. collective lattice vibrations, whereas organic insulators (like polymers) offer numerous molecular groups to the vibrational excitation by the electron beam (extrinsic vibrations). Quantitative analysis of the surface of those materials rests on the understanding of the interaction mechanisms between monochromatized electrons and intrinsic or extrinsic vibrations.Three scattering processes have been recognized to contribute to HREEL spectra: dipole interaction, impact scattering and resonance scattering. They have been characterized theoretically and experimentally through their dependence versus variation of the electron beam energy and/or of the scattering angular geometry.Recent experiments have shown that the analysis of intrinsic phonons is very well understood for insulators. As a consequence, quantitative analysis of compound semiconductors is possible and brings additional information on the surface stoichiometry (of AlxGa1-xAs, for example) and on the doping level. For organic polymers, however, the excitation of molecular vibrations does not - up to now - appear to follow a simple scheme: all the scattering mechanisms (dipolar, impact and resonance) appear to play a significant role; a true quantification will be possible only through a systematic study of model compounds, and will require further theoretical treatments.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740150302
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