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A MoO(sub x)/SiO(sub 2) catalyst prepared with a Mo loading of 0.44 Mo/nm(super 2) consisted of isolated, pentacoordinated molybdate species containing a single Mo=O bond. Raman spectroscopy results showed that these are reduced by H(sub 2) to molybdate species containing Mo(super IV) cations but methane and CO are not effective reducing agents hence active species for methane oxidation is a peroxide species formed by the reaction of oxygen with the low concentration of reduced molybdate species present on catalyst surface.

A demonstration that electrochemical machining of p-Si substrates may be accomplished in an HF-based solution using nanosecond pulses applied between the substrate and a tungsten tool electrode is presented. The study concluded that micrometer precision may be obtained with highly doped substrates and that experimental data can be explained within a simple model, taking the charging time of the interface without application of a mask on the surface.

The adsorption of systematically substituted silanes with either simple alkyl or alkyl phenyl ether chains onto oxidized Si is used to study the electronic effects of such molecular monolayers on Si. It is concluded that there is no significant change in surface potential if the length or structure of the connecting chain between the attached dipolar unit and the silicon surface is varied.

A new class of nanoparticles and tree-like aggregates is assembled by the influence of an electric filed during the synthesis of metallic, intermetallic, carbon, and silicon nanoparticles from the vapor phase. Enormous electrostatic aggregation due to dipole forces is observed between the nanoparticles to form chain filaments, and between the chain filaments to form tree-like fibers.

The adsorption and thermal decomposition behavior of azomethane on the Si(111)-7 x 7 surface is studied by high-resolution electron energy loss spectroscopy (HREELS), synchrotron radiation photoelectron spectroscopy in the soft x-ray and UV photon energy ranges, and scanning tunneling spectroscopy (STM). It is found that at 90 K substrate temperature, azomethane is adsorbed largely intact in both trans and cis forms.

The hybrid materials constituted by polypyrrole doped with the polyoxometalate (POM) anion [SiCr(H2O)W11O39](super 5-) are electrogenerated from acetonitrile solutions. The electrochemical behavior of the hybrid films is studied by cyclic voltammetry in three different electrolytes formed by two anions and two cations dissolved in acetonitrile.

The retention of aromaticity is a strong driving force controlling selectivity in bonding of multifunctional molecules to the Si(001) surface. The difference in selectivity between Pyrrole and its derivative 3-pyrroline helps to distinguish between the structural and electronic factors controlling the adsorption process.

The (super 23)Na and (super 29)Si NMR spectra of the sodium-silicon clathrate materials Na(sub 8)Si(sub 46) and Na(sub x)Si(sub 136) are studied in detail. NMR, XPS and XANES results showed an interaction between Na atom and the Si framework of the clathrates.

A new study investigates the transient photocurrent in hydrogenated amorphous silicon in all relevant time regimes and light-intensity ranges.

Si electrodes in alkaline solutions undergo electrodissolution and passivation when H-terminated Si is irreversibly oxidated to a monohydroxylated surface species. The latter may also undergo further oxidation to form a dihydroxylated species causing 2D surface blocking or as an Si(II) species producing an H-terminated species. The blocking species may be dissolved as Si(IV). Both physical phenomena can also occur when water reacts with Si and H2.

Research was conducted to examine the electrochemical characteristics of alkyl-terminated, (111)-oriented, n-type Si surfaces, prepared using a two-step halogenation/alkylation method. The analysis was carried out in contact with CH3OH-1,1'-dimethylferrocene(super +/0) (Me2Fc(super+/0)) solutions. Results suggest that the electrochemical properties of the alkyl-terminated surfaces were very similar to those of the H-terminated Si surface.

Terbium-exchanged MFI zeolite type materials, microporous-mesoporous Zeolite-1 with the Si/Al ratio in the range of 33-200, Zeogrid with the Si/Al ratio of 75 and nanocrystalline MFI with Si/Al ratio 75 were prepared via an ion exchange procedure and investigated by time resolved photoluminescence techniques. The results show that, in Zeolite 1 and Zeogrid, two distinct locations of [Tb.sup.3+] exist which might correlate with two types of exchange sites, one on the internal surface of mesopores, the other inside the pores while for MFI, the site predominate inside the pores.

Comparative electrodeposition of iron onto the surface of silicon is investigated at large overpotential in the presence of some base electrolytes and the nanostructure of the iron electrodeposits was analyzed with scanning electron microscopies (SEM) and field emission-SEM (FE-SEM) measurements. The results have highlighted the effects of ion specificity on the rate of hydrogen evolution and of selective ion adsorption on the morphology of the iron electrodeposits.

The computational and infrared studies of the reactions of nitrobenzene on a Si(100) surface which is a prototypical model reaction for understanding the behavior of bifunctional molecules on semiconductor surfaces is described. Computational exploration suggests that two stable structures could be formed and the initial reaction of nitrobenzene with the Si(100)-2*1 occurs through 1,3-dipolar cycloadditions of the nitro group to the silicon surface dimer.

The intermediate structures of the aggregates in the aqueous solution of an ABA-type silicone surfactant and in the process of an SDS-induced vesicle-micelle transition are described. The electrical conductivity measurements have shown that complex micelles of SDS and silicone surfactant were formed in the solution due to the interaction between the SDS and poly(ethylene oxide) (PEO) part of the silicone surfactant.

Si(111)-alkyl layer interfaces are prepared with a very low density of electronic traps after careful control of the grafting conditions. Water exclusion from the monolayer has promoted long-term passivation of the silicon surface against oxidation in air and water as well as perfect corrosion inhibition in 20% NH4F.

The preparation of gold nanoparticles directly deposited onto the surface of silicon and sapphire substrates by a physical methodology, consisting in the thermal evaporation of a thin Au film and its successive annealing is reported. The method guarantees the preparation of monodispersed single-crystal Au nanoparticles with a strong surface plasmon resonance peak centered at about 540 nm.

The cumulative double bond (C=C=C), an important intermediate in synthetic organic chemistry, was successfully prepared via the selective attachment of acetylethyne to Si(111)-7 X 7. The cumulative double bonds C=C=C may be considered as a precursor for further dry organic syntheses ad modification of silicon surfaces.

The alignment of energy levels and chemical interaction of the organic pigments ZnPc, substituted F16ZnPc, and ZnTPP on H-terminated Si(111) derived from valence band and core level photoelectron spectroscopy with high surface sensitivity for coverage below and in the monolayer region is reported.

Hybrid density functional calculations is carried out on a cluster models of the pristine and oxidized hydrogen-terminated Si(100)-2x1 surface in order to examine the changes in the surface infrared absorption spectrum upon incorporation of oxygen. A tremendous increase in the nu(Si-H) band intensity is found for the oxidized surface due to a combination of geometric and electronic effects.

The nylon-6 and polystyrene as prototypical materials with organic groups are used to demonstrate that for silicon or gold substrates, features due to the molecular vibrations can be seen in the ellipsometric spectra for thin films with signal to noise ratios ranging from 2 to 10. For all the substrates, infrared (IR) ellipsometry provides molecular structure information.

A detailed characterization of thiophene terminated Si(111) surfaces and photoelectrochemical growth of polythiophene on these surfaces is presented. This process leads to the formation of robust conducting polymer/silicon junctions in which the polymer is covalently linked to the silicon substrate through an alkyl spacer.

Photocatalytic systems have the potential to promote difficult reactions and are examined in both oxidative and nonoxidative systems for methane conversion. The results suggest that the pair sites consisting of the dispersed AlO4 and TiO4 species are responsible for a high activity of the SiO2-Al2O3-TiO2 photocatalyst in this reaction.

The microwave reflectance methods were used to study the kinetics of photogeneration of hydrogen on p-Si in acidic fluoride solutions. The surface charging as the result of slow kinetics was expected to lead to band edge even at low light intensities, and the existence of this effect was confirmed by transient photocapacitance measurements.

Four methods such as Lewis acid-mediated reduction of a terminal alkene, anodixzation in diethyl ether containing 3.0 M CH(sub 3)MgI are used to fictionalize crystalline Si(111) surfaces with alkyl groups. The chemical properties of each surface are characterized as a function of time exposed to air using X-ray photoelectron spectroscopy and the electrical properties of the various surfaces are probed using time-resolved radio frequency photoconductivity decay methods.

The adsorption of several simple methylamines on the Si(100)-(2 x 1) surface is examined with the help of Auger electron spectroscopy (AES), thermal desorption spectroscopy, low-energy electron diffraction. The conclusion states that the surface saturation coverage of trimethylamine on Si(100) is 0.26 manolayers, consistent with the photoemission results, while both methylamine and dimethylamine appear to saturate at about 0.48 monolayers.

Epitaxial films of cuprous oxide, Cu2O, are electrodeposited from the aqueous solution onto single-crystalline Si(001). Cross-sectional transmission electron microscopy studies suggest that the growth mechanism involves an initial electroless deposition of Cu2O epitaxial seeds in direct contact with the Si(001).

The investigation on the covalent binding and structure of acetonitrile on Si(111)-7 * 7 is done to provide information on the interaction of pi-electrons of the C triple bond N group with the dangling bonds of Si(111)-7 * 7. The density functional theory (DFT) calculation results and all the experimental evidence revealed that functional organic monolayer of acetonitrile on Si(111)-7 * 7 are formed through a di-sigma binding mechanism involving the coupling of one pi(sub CN) bond with an adatom-rest atom pair at the interface.

The fabrication and properties of composite films composed of poly(phenylene vinylene) (PPV) and Erbium(Er)-doped silicon (Si) Nan crystals are presented. The presence of Er-doped Si nanoparticles in the film are found strongly impacting the steady-state photoluminescence of the PPV, while the presence or absence of solvent chosen for the nanocrystals influence the carrier transport and resultant visible electroluminescence of light-emitting diodes fabricated from these materials.

A quantitative analysis of Ti K-edge XANES spectra is used to obtain information about the Ti environment in Ti-Si binary oxides, including acid-catalyzed xerogels with molar ratios Ti/Si of 0.01 to 0.50. The results clarify a number of points concerning Ti environments in these xerogels.

A study was conducted to examine the surface chemistry of silicon in alkaline solution. The result shows that the surface chemistry and electrochemistry are determined to a large extend by an activated intermediate of the chemical etching reaction of silicon with water.

Adsorption and decompostion of tert-butylacetylacetate (tBAA) on S9(100) is investigated by using static secondary in mass spectrometry and temperature-programmed desorption. Results show that at low doses all tBAA molecules dissociate readily upon adsorption on the surface at temperatures as low as 160 degreeC.

The preparation of 20 (plus or minus) 5 nm diameter Si nanowires and the electrical characterization of Si nanowire devices are presented. The wires were investigated by high-resolution transmission electron microscopy.

An attempt was made to prepare thermal-sensitive surfaces by grafting poly(N-isopropylacrylamide) PNIPAAm on the surface of silicone wafers without a cross-linking agent. Dramatic changes of the hydrophilic/hydrophobic surface were observed by investigating the variation of the advancing contact angles.

The surface reactions of thiophene on Silicon(100)-2 x 1 are investigated as part of a larger study on the interaction between five-member heterocyclic aromatic molecules and silicon substrates. The growing interest in studying thiophene and its derivatives lies not only in better understanding of the electronic properties of five-membered heteroatom aromatic rings, but in practical realms as well.

The effect of photoexcitation of the adsorbed species on the electronic properties of the surface is investigated applying wavelength and time dependent two-photon photoemission spectroscopy. The conclusion states that photoexcitation of a small fraction of the weakly bound RB species causes a significant change in the electronic properties of the substrate.

Organic modification of oxide-free silicon surfaces offers a direct combination of molecular materials and solid-state semiconductor structures, making it an attractive approach to provide technologically useful and molecularly tunable thin films. The fabrication and characterization of these organic thin films covalently bound to silicon surfaces promise to improve the stability toward oxidation and to maintain satisfactory electrical properties of silicon electrodes.

The formation of precursors in the crystallization of Si-MFI from clear solutions using as the structure-directing agent bis(tripropylammonium) hexamethylene dihydroxide and bis(tripropylammonium-N-N'-hexamethylene)-N',N'-dipropylammonium trihydroxide are investigated. The result confirms that a common mechanism is proposed for organic-mediated crystallization of high-silica zeolites.

The vibrational modes of double four-member ring fragments (D4R), where Si and Al occupy tetrahedral sites and M(super +) is a monovalent charge compensating cation, are assigned to the framework vibrations of Linde type A (LTA) zeolites. The normal vibrations that arise from configurations with different Si, Al arrangements are calculated by the B3LYP method.

A (super 27)Al 3Q magic angle spinning (MAS), a quantitative (super 27)Al MAS, and a (super 29)Si MAS NMR study is carried out on La(x)NaY and H-USY. The (super 29)Si MAS and (super 27)Al MAS NMR results obtained at high fields (14.1 T) and fast MAS up to 27 kHz made a quantitative assignment possible of the framework and nonframework Al coordinations.