Characterization, film elemental

Copper, silver, and gold colloids have been prepared by Chemical Liquid Deposition (CLD) with dimethoxymethane, 2-methoxyethyl ether, and ethylene glycol dimethyl ether. The metals are evaporated to yield atoms which are solvated at low temperatures and during the warm-up process colloidal sols with metal clusters are obtained. Evaporation of the solvent was carried out under vacuum-generating metal films. These films are showing very low carbon/hydrogen content and were characterized by elemental analyses and infrared spectroscopy (Cardenas et al., 1994). 

Thin-Film Elemental Analyses for Precise Characterization of Minerals... 

All of the new derivatives were off-white colored materials that formed brittle films. They were characterized by elemental analysis and NMR spectroscopy. The salts required extended periods of drying to completely remove all solvents, after which they gave satisfactory elemental analysis. 

Two triphenylamino-substituted chromophores with and without hydroxyl end, named TIOH and Tl (Figure 6.7), respectively, were synthesized and incorporated into hybrid organic-inorganic materials derived from 3-glydoxypropyltrimethoxysi-lane, tetraethoxysilane, and 3-aminopropyltriethoxysilane [54]. These stilbene-type chromophores were characterized by elemental analysis by NMR, FT-IR, UV-vis spectra, and TGA. The hyperpolarizabilities were characterized through solvato-chromic method. Both chromophores possessed higher thermal stability and competitive hyperpolarizabilities. Second harmonic generation was observed on poled films. The nonlinear coefficient of the samples was established at 41.2 pm/V for TIOFJ doped film and at 24.8 pm/V for Tl doped film. 

The chemical and electronic properties of elements at the interfaces between very thin films and bulk substrates are important in several technological areas, particularly microelectronics, sensors, catalysis, metal protection, and solar cells. To study conditions at an interface, depth profiling by ion bombardment is inadvisable, because both composition and chemical state can be altered by interaction with energetic positive ions. The normal procedure is, therefore, to start with a clean or other well-characterized substrate and deposit the thin film on to it slowly at a chosen temperature while XPS is used to monitor the composition and chemical state by recording selected characteristic spectra. The procedure continues until no further spectral changes occur, as a function of film thickness, of time elapsed since deposition, or of changes in substrate temperature. 

The majority of deposits formed in this group have been on Au electrodes, as they are robust, easy to clean, have a well characterized electrochemical behavior, and reasonable quality films can be formed by a number of methodologies. However, Au is a soft metal, there is significant surface mobility for the atoms, which can lead to surface reconstructions, and alloying with depositing elements. In addition, Au it is not well lattice-matched to most of the compounds being formed by EC-ALE. 

For a given detector and a given pair of elements the last two factors give a single constant (Icab) that can be treated as a relative sensitivity factor. Both that factor and the method obtained their names after the two people who introduced them, Cliff and Lorimer (1975). The simplicity originates from the fact that the Uab factor does not depend either on the rest of elements also present in the sample or on the other parameters of the sample (thickness, density), as far as the thin film criterion is fulfilled. The Cliff-Lorimer factors can either be calculated using the known parameters of the detector or can be measured if a well-characterized thin film sample (standard) is available. In the first case the method is standardless. In the second case the known weight fractions and the measured intensity ratio provides the Cliff-Lorimer factor for the pair of elements. 

The sample surface is bombarded with a beam of around 1 keV ions of some gas such as argon and neon. The action of the beam sputters atoms from the surface in the form of secondary ions, which are detected and analyzed to produce a characterization of the elemental nature of the surface. The depth of the analysis is usually less than a nanometer, making this process the most suitable for analyzing extremely thin films. 

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