- Hydrostatic pressure dependence of the photoluminescence of Si nanocrystals in SiO2
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We have measured the hydrostatic pressure dependence of the photoluminescence (PL) of Si nanocrystals in SiO2 layers at room temperature and at pressures up to 50 kbar. The samples were fabricated by ion implantation and subsequent annealing. For the two
- Cheong, Hyeonsik M.,Paul,Withrow,Zhu,Budai,White,Hembree Jr.
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- Crystallization of Amorphous Silicon Thin Films Using a Viscous Nickel Solution
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A viscous Ni solution was applied on amorphous Si films and its effect on the crystallization of amorphous Si films was investigated. A viscous Ni solution was prepared by dissolving NiCl2 in 1 N HCl and mixing it with propylene glycol. NiCl2 and Ni was uniformly deposited by spin coating and drying the viscous metal solution, and it enhanced the crystallization at lower temperature overcoming the nonuniform coating of diluted acid metal solution. The a-Si films deposited by low pressure chemical vapor deposition with Si2H6 were fully crystallized in 10 h at 500°C by furnace annealing and in 8 h at 480°C by microwave annealing. The enhanced crystallization was due to the mediation by NiSi2. The surface roughness of the crystallized Si films using the Ni solution was smoother than that of the crystallized Si films with Ni metal layer.
- Ahn, Jin Hyung,Ahn, Byung Tae
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- Mechanism of photoluminescence of Si nanocrystals fabricated in a SiO2 matrix
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The luminescence properties of silicon nanocrystals fabricated by Si ion implantation into a SiO2 matrix and subsequent thermal annealing have been studied. To identify the mechanism of photoluminescence of Si nanocrystals, the dependencies of the steady-state photoluminescence on temperature and excitation power density, and the time-resolved photoluminescence have been investigated. The experimental results point to the mechanism of recombination via the levels of centers which are presumably localized at the silicon nanocrystal-silicon dioxide boundary.
- Zhuravlev,Gilinsky,Kobitsky
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- The effect of surface nucleation on the evolution of crystalline microstructure during solid phase crystallization of amorphous Si films on SiO2
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The effect of surface nucleation on the evolution of crystalline microstructure during the solid phase crystallization (SPC) of an amorphous Si (a-Si) film, deposited by low pressure chemical vapor deposition (LPCVD) on SiO2, has been investigated. The surface nucleation phenomenon was observed by suppressing the interface (a-Si/SiO2) nucleation by the incorporation of oxygen atoms during the initial deposition period of a-Si. It was found that the surface-nucleated polycrystalline Si (poly-Si) had equiaxial grains with the size of about 3-5 μm, while interface-nucleated one had elliptical grains with the size of about 0.3-1 μm.
- Ryu, Myung-Kwan,Hwang, Seok-Min,Kim, Tae-Hoon,Kim, Ki-Bum,Min, Seok-Hong
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- Thermally deposited amorphous silicon
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We investigated a thermally deposited amorphous silicon (TAS) film before and after annealing. We used monosilane (SiH4) or disilane (Si2H6) as the Si source gas at a deposition pressure of 0.1 to 0.5 Torr. The activation energy of SiH4 deposition was 1.7 eV (560 to 600 °C) and that of Si2H6 was 0.6 eV (510 to 570 °C). From TEM observation, the TAS film from 450 °C Si2H6 deposition was completely amorphous without crystals and had a smooth surface. Film deposited at 560 °C had a few crystals at the Si/SiO2 interface and had a few bumps on the Si surface. After annealing, the mean grain size of 450 °C-Si2H6 film was about 2 μm and that of 560 °C-SiH4 film was about 0.3 μm. We also evaluated the crystallinity by XRD and Raman spectroscopy. Films deposited at lower temperatures after annealing showed strong 〈111〉-orientations and high crystal qualities.
- Mieno,Sukegawa,Iizuka,Miyata,Nomura,Tsukune,Furumura
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- White light emission from a mixture of silicon quantum dots and gold nanoclusters and its utilities in sensing of mercury(ii) ions and thiol containing amino acid
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White light emitting mixture (WLEM) was produced by controlled mixing of blue emitting silicon quantum dots (Si QDs) and orange red emitting gold nanoclusters (Au NCs). The chromaticity color co-ordinate of the WLEM studied using CIE (Commission Internationale del'Eclairage) diagram was found to be (0.33, 0.32), which was very close to that of perfect white light emitting source. The WLEM can also be achieved in the form of gel, solid and film with nearly the same CIE co-ordinates which enhances its utility as white light-emitting source in solid state devices. The reversible and thermo-responsive behaviour of the WLEM broadens its application in thermal sensing. Furthermore, the system was found to be showing fast, sensitive and selective detection of Hg2+ ions and thiol containing amino acid cysteine.
- Tanwar, Swati,Sharma, Bhagwati,Kaur, Vishaldeep,Sen, Tapasi
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- The metallic Zintl phase Ba3Si4 - Synthesis, crystal structure, chemical bonding, and physical properties
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The Zintl phase Ba3Si4 has been synthesized from the elements at 1273 K as a single phase. No homogeneity range has been found. The compound decomposes peritectically at 1307(5) K to BaSi2 and melt. The butterfly-shaped Si46- Zintl anion in the crystal structure of Ba3Si4 (Pearson symbol tP28, space group P42/mnm, a = 8.5233(3) A, c = 11.8322(6) A) shows only slightly different Si-Si bond lengths of d(Si-Si) = 2.4183(6) A (1x) and 2.4254(3) A (4x). The compound is diamagnetic with χ ≈ -50 × 10-6 cm3 mol-1. DC resistivity measurements show a high electrical resistivity (ρ(300 K) ≈ 1.2 × 10 -3 Ω m) with positive temperature gradient dρ/dT. The temperature dependence of the isotropic signal shift and the spin-lattice relaxation times in 29Si NMR spectroscopy confirms the metallic behavior. The experimental results are in accordance with the calculated electronic band structure, which indicates a metal with a low density of states at the Fermi level. The electron localization function (ELF) is used for analysis of chemical bonding. The reaction of solid Ba3Si4 with gaseous HCl leads to the oxidation of the Si46- Zintl anion and yields nanoporous silicon.
- Aydemir, Umut,Ormeci, Alim,Borrmann, Horst,Boehme, Bodo,Zuercher, Fabio,Uslu, Burcu,Goebel, Thorsten,Schnelle, Walter,Simon, Paul,Carrillo-Cabrera, Wilder,Haarmann, Frank,Baitinger, Michael,Nesper, Reinhard,Von Schnering, Hans Georg,Grin, Yuri
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- Initial carrier relaxation dynamics in ion-implanted Si nanocrystals: Femtosecond transient absorption study
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Transient absorption spectra of ion-implanted Si nanocrystals (NCs) exhibit two picosecond photoinduced absorption features, attributed to carriers in NC quantized states (high-energy band) and Si/SiO2 interface states (low-energy band). Fast relaxation of the high-energy band indicates that populations of quantized states are short lived and decay on the sub-10-ps time scale due to efficient surface trapping. This shows that the red emission in our samples is not due to carriers in quantized states but rather is a result of deactivation of surface traps.
- Klimov,Schwarz,McBranch,White
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- Nanometer-scale Si selective growth on Ga-adsorbed voids in ultrathin SiO2 films
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We examined nanometer-scale Ga selective doping by Si growth on Ga-adsorbed voids in ultrathin silicon-dioxide on Si(111) surfaces. The doping processes were observed by scanning tunneling microscopy (STM). Voids in ultrathin oxide films were plugged with a (√3 × √3)-Ga structure, and the selective growth was performed by introducing disilane gas (Si2H6). Si crystals were selectively grown only in the voids at 460-550°C. Two-dimensional nucleation was found to start from the edge of the voids. Incorporated Ga atoms mostly segregated during the selective growth and were reconstructed to the (√3 × √3) structure by annealing at 600°C. These results show that Ga doped dots of nanometer-scale can be formed by selective epitaxial growth using an ultrathin silicon-dioxide mask.
- Nitta, Yoshiki,Shibata, Motoshi,Fujita, Ken,Ichikawa, Masakazu
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- Fabrication of solution-processed hydrogenated amorphous silicon single-junction solar cells
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Hydrogenated amorphous silicon solar cells were fabricated using solution-based processes. All silicon layers of the p-i-n junction were stacked by a spin-cast method using doped and non-doped polydihydrosilane solutions. Further, a hydrogen-radical treatment under vacuum conditions was employed to reduce spin density in the silicon films. Following this treatment, the electric properties of the silicon films were improved, and the power conversion efficiency of the solar cells was also increased from 0.01% to 0.30%-0.51% under the AM-1.5G (100 mW/cm2) illumination conditions.
- Masuda, Takashi,Sotani, Naoya,Hamada, Hiroki,Matsuki, Yasuo,Shimoda, Tatsuya
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- Efficient defect passivation by hot-wire hydrogenation
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Atomic hydrogen, produced at a hot wire, passivates bulk defects in polycrystalline silicon without damaging surface regions. Solar cells from such polycrystalline silicon respond much more favorably to hot-wire hydrogenation than to low-energy ion implantation or a direct-current plasma treatment. Hot-wire passivation yields a hydrogen concentration close to the surface of 8 × 1019 cm-3 and improves the minority carrier diffusion length of solar cells by up to 100%. Implantation as well as conventional plasma treatment result in lower hydrogen concentration and, consequently, in much smaller improvements of diffusion lengths.
- Plieninger,Wanka,Kuehnle,Werner
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- Etching, insertion, and abstraction reactions of atomic deuterium with amorphous silicon hydride films
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We report structural and kinetic studies of the reactions of hydride species in Si thin films with atomic deuterium (Dat). Infrared (IR) spectroscopy is used to obtain Si-H bonding information, and direct recoiling methods are used to measure reaction rates. Two kinds of films are prepared by filament-assisted growth from Si2H6 and are characterized by IR spectroscopy. A film containing only monohydride hydrogen is grown at 200 °C, and a polymer containing tri-, di-, and monohydride is grown at -110°C. Rates of H abstraction by Dat, and of Dat insertion into Si-Si bonds, are reported. The abstraction rate of H by Dat in both films is similar to the abstraction rate on H-terminated crystal Si surfaces. The insertion rate into Si-Si bonds in both films is about one-tenth the rate of abstraction. A qualitative study of the etching reaction of Dat with the polymeric film is reported, and a strong temperature dependence is observed.
- Chiang,Gates,Lee, Szetsen S.,Kong,Bent, Stacey F.
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- Roles of SiH4 and SiF4 in growth and structural changes of poly-Si films
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The structural properties of polycrystalline silicon films, prepared by plasma enhanced chemical vapor deposition system, with different flow rates of SiH4/SiF4 mixtures at 300 °C were investigated. This study indicates that the low
- Haddad-Adel,Inokuma,Kurata,Hasegawa
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- Synthesis of Crystalline Silicon Tubular Nanostructures with ZnS Nanowires as Removable Templates
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Silicon epitaxy on ZnS nanowires results in the formation of ZnS/Si core/shell nanowires; chemical removal of the zinc blende nanowire templates produces monocrystalline silicon tubular nanostructures with outer diameters of about 60-180 nm, wall thicknes
- Hu, Junqing,Bando, Yoshio,Liu, Zongwen,Zhan, Jinhua,Goldberg, Dmitri,Sekiguchi, Takashi
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- CATHODIC DEPOSITION OF AMORPHOUS SILICON FROM TETRAETHYLORTHOSILICATE IN ORGANIC SOLVENTS.
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A blue thin film of amorphous silicon has been deposited on a nickel cathode by the electrolysis of a solution of tetraethylorthosilicate in acetic acid. The maximum thickness of the film obtained was about 0. 5 mu m. The deposit was confirmed to be amorphous silicon by IR reflection spectra, RHEED, and nondispersive x-ray analysis in the scanning electron microscope. This work is pertinent to solar cells.
- Takeda,Kanno,Yamamoto,Mohan,Chia-Hao Lee,Kroger
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- Effects of hydrogen surface pretreatment of silicon dioxide on the nucleation and surface roughness of polycrystalline silicon films prepared by rapid thermal chemical vapor deposition
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It is well known that Si surface treatment is crucial for low-temperature Si epitaxy. Although considerable work exists which is aimed at elucidating the effects of Si surface pretreatments on Si epitaxy, little is known about the effects of SiO2 surface pretreatments for polycrystalline silicon (poly-Si) growth. We report on a study of SiO2 surface pretreatment effects on poly-Si nucleation and film surface roughness using a low energy hydrogen ion beam (200 eV) and H2 gas annealing (850°C) in a rapid thermal chemical vapor deposition system. In situ real-time ellipsometry was used to monitor the surfaces during pretreatment and observe the nucleation. The microstructure and surface roughness of the deposited poly-Si films are determined by analysis of in situ spectroscopic ellipsometry (SE) and atomic force microscopy (AFM) measurements. Hydrogen ion beam pretreatment was found to produce higher nuclei density and a smoother poly-Si surface than nonpretreated substrates, and the opposite was found for hydrogen gas annealing giving lower nuclei density and rougher poly-Si.
- Hu,Zhao,Basa,Gao,Irene
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- Theoretical/experimental study of silicon epitaxy in horizontal single-wafer chemical vapor deposition reactors
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The main goal of this study is to examine the possibility of using detailed three-dimensional simulations of transport of momentum, energy, and mass in horizontal single-wafer epitaxial silicon reactors in conjunction with relatively simple kinetic models to describe the reactor's performance over the entire range of operating conditions. As the SiHCl3-H2 system is a widely used precursor for epitaxial silicon deposition in industrial applications, we have chosen to focus our model development on this system. In the development of the model we have considered the dependence of the gas properties on the gas composition as well as on the temperature. In addition, mass transport due to thermal diffusion has been considered. The accuracy of the simulation model has been examined by comparing the predicted silicon deposition rates and profiles in two commercial chemical vapor deposition (CVD) reactors with the experimentally measured values. A comparison of simulation and experimental results has indicated that a detailed transport model in conjunction with a Langmuir-Hinshelwood type kinetic model for silicon deposition accurately describes the epitaxial silicon deposition rate and deposition profile. In turn, this lumped reaction kinetic model has been used for optimization of commercially available horizontal CVD reactors for epitaxial deposition of silicon.
- Kommu, Srikanth,Wilson, Gregory M.,Khomami, Bamin
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- Optical properties of n-type porous silicon obtained by photoelectrochemical etching
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The optical studies of n-type porous silicon prepared by the photo-assisted chemical etching are reported here. The optical properties of samples obtained under different conditions have been investigated by photoluminescence and Fourier transform infrared absorption measurements, and they are compared with that of p-type porous silicon. Our results clearly demonstrate that the blue emission in porous silicon originates from surface compounds. From the infrared absorption measurement, we point out that the surface compounds are Si-OH complexes. This conclusion is further supported by a recent calculation which shows that Si-OH complexes can emit the photon energy in the range observed here. We show that the optical properties of the n-type porous silicon are more stable than that of the p-type porous silicon. The result provides the evidence to support the fact that the n-type porous silicon is a better candidate for the application in optoelectronics.
- Chen,Chen
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- The influence of cooling rate on the formation of an amorphous phase in Si-based multicomponent alloys and its thermal stability
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By adding Ni, Cr, and Zr to the Si-Al-Fe system and using a higher surface velocity of the copper wheel of 63 m/s, the composition range of an amorphous single phase was extended to 60 at% Si. An amorphous Si60Al18Fe12Ni4Cr3Zr 3 alloy was produced. The amorphous phase in the Si-Al-TM (TM = transition metals) alloys shows higher thermal stability than in the Al-Si-TM alloys. By the shift of differential scanning calorimetry (DSC) peaks with change of heating rate, the activation energy for the transformation was determined to be 343 kJ/mol for Si55Al20Fe10Ni5Cr5Zr 5 alloy and 374 kJ/mol for Si50Al25Fe10Ni5Cr5Zr 5 alloy.
- Louzguine, Dmitri V.,Inoue, Akihisa
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- Wide fluctuations in fluorescence lifetimes of individual rovibronic levels in SiH2 (1B1)
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We have measured fiuorescence lifetimes of individual rovibronic levels in SiH2 (1B1,020).The lifetimes vary widely from one level to the next, ranging from 10 ns to 1 μs.Similar behavior is seen in the (000), (010), and (03
- Thoman, J. W.,Steinfeld, J. I.,McKay, R. I.,Knight, A. E. W.
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- The Silicon-Boron system
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RECENTLY the synthesis of a compound of the composition SiB4 has been reported in two articles1,2. Concurrent with this work we have been investigating this compound as a part of our programme for studying high-temperature materials.
- Brosset, Cyrill,Magnusson, Bengt
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- Fabrication of poly-Si films by continuous local thermal chemical vapor deposition on flexible quartz glass substrate
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The continuous deposition of polycrystalline silicon film on quartz fiber by local thermal chemical deposition was investigated. High-speed deposition owing to high temperature and locality was examined using fixed and moving substrates. We confirmed the high-speed deposition of polycrystalline silicon and achieved a maximum speed of over 1 μms. Furthermore, we succeeded in a continuous deposition of polycrystalline thin silicon with a thickness of 50-100 nm on a quartz fiber with low roughness and low impurity content. Thin film transistor with a mobility more than 3.7 cm2 V s was achieved by using this film.
- Nakamura,Kuraseko,Hanazawa,Koaizawa,Uraoka,Fuyuki,Mimura
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- Absorption spectroscopy of SiH2 near 640 nm
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The A 1B1-X 1A1 absorption spectrum of SiH2 has been observed using intracavity laser absorption spectroscopy with an equivalent path length of up to 13.0 km and the A 1B1(0, 0, 0)-X 1A1(0, 0, 0) band near 640 nm recorded for the first time. The silylene radical was generated in a continuous discharge in a flowing mixture of silane in argon, giving a concentration of the order of 1010 SiH2/cm3. The spectrum spans the region between 15350 and 16100 cm-1. Rotational transitions have been assigned to levels up to J = 16 and Ka = 9, with ΔKa up to 5, ΔKc up to 4. Perturbations have been detected in the spectrum, due to Renner-Teller and spin-orbit interactions between both electronic states and the 3B1 state, predicted to be between them. However, the strength of the irregular perturbations affecting the rotational states of A 1B1(0,0,0) state is found to be much weaker than that affecting the other (0, v′2, 0) levels previously studied. The analysis of the spectrum has allowed the determination of the rotational constants of the 1B1 (0,0,0) level, and a new estimation of those of the vibrational and electronic ground state. The geometry of the excited electronic level has also been determined for the first time from accurate experimental data. A change in the structure of this molecule takes place with this transition, the equilibrium angle opening from 92° to 122.4°, while the bond distance is reduced from 1.51 to 1.485 A.
- Escribano, Rafael,Campargue, Alain
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- Fabrication of silicon-submicron-wire-based solar cells on UMG-Si substrates using nickel catalyst
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Solar cells based on arrays of vertical Si submicron or nano-sized wires are promising candidates for lowering production-related material costs while still obtaining efficiencies competitive with those of planar multicrystalline Si cells. To the best of our knowledge, our study is the first to examine the growth of silicon submicron wires on upgraded metallurgical-grade Si (UMG-Si) substrates catalyzed by nickel (Ni) using the chemical vapor deposition technique. We examined which conditions are most favorable for the growth of silicon submicron wires by varying the annealing temperature and the annealing time duration: Ni film was annealed with a temperature range of 900-975°C and a time range of 2-12 min. We subsequently analyzed and compared the output characteristics of the silicon submicron-wire-based (Si-SMW-based) solar cells. Our results indicate that silicon wires with diameters ranging from 0.2 to 0.8 μm could be grown with the present technique. Moreover, a conversion efficiency of greater than 1 was achieved for the Si-SMW solar cells fabricated with the Ni catalytic film annealed at 950°C. In particular, annealing the Ni catalytic film for 2 min while growing the submicron wire structure produced a solar cell with an efficiency as high as 2.06%.
- Chiang, Chin-Hsuan,Ci, Ji-Wei,Uen, Wu-Yih,Lan, Shan-Ming,Liao, Sen-Mao,Yang, Tsun-Neng
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- Clathrates of group 14 with alkali metals: An exploration
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The quantitative synthesis of four silicon and germanium compounds with the clathrate-II structure, Cs8Na16Si136 (1), Cs8Na16Ge136 (2), Rb8Na16Si136 (3), and Rb8Na16Ge36 (4), and their characterizations are reported. The corresponding Si-Si and Ge-Ge distances are determined with high accuracy from extensive single-crystal X-ray diffraction work. The compounds (cubic, space group Fd3m, a=14.7560(4), 15.4805(6), 14.7400(4), and 15.4858(6) A for 1, 2, 3, and 4, respectively) are stoichiometric, metallic, and remarkably stable. No evidence was found for vacancies in the silicon and germanium networks or partial occupancies of the alkali metal sites. The stoichiometry of these completely filled clathrates is consistent with the measured temperature-independent Pauli paramagnetism (χ = 7.2 x 10-4, 6.5 x 10-4, 6.9 x 10-5, and 1.4 x 10-4 emu/mol for 1, 2, 3, and 4, respectively) and metallic resistivity (ρ293 ? 10-5 Ω-cm). (C) 2000 Academic Press.
- Bobev, Svilen,Sevov, Slavi C.
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- Operation mechanism of Schottky barrier nonvolatile memory with high conductivity InGaZnO active layer
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Influence of Schottky contact between source/drain electrodes and high conductivity a-InGaZnO active layer to the performance of nonvolatile memory devices was first proposed. The Schottky barrier devices faced to the difficulty on electrical discharging process due to the energy barrier forming at the interface, which can be resolved by using Ohmic devices. A memory window of 2.83V at programming/erasing voltage of ± 13V for Ohmic and 5.58V at programming voltage of 13V and light assisted erasing at -7 V for Schottky devices was obtained. Both memory devices using SiO2/SiO x/SiOxNy stacks showed a retention exceeding 70% of trapped charges 10 yr with operation voltages of ±13V at an only programming duration of 1ms.
- Trinh, Thanh Thuy,Nguyen, Van Duy,Nguyen, Hong Hanh,Raja, Jayapal,Jang, Juyeon,Jang, Kyungsoo,Baek, Kyunghyun,Dao, Vinh Ai,Yi, Junsin
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- Separation of silicon isotopes by silicon tetrafluoride-silane technology
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Silane enriched in silicon isotopes was obtained in high yield by reacting SiF4 with a solution of NaAlH4 in diethylene glycol dimethyl ether in a purpose-designed apparatus. Chemical analyses are presented for isotopically enriched silicon obtained by the thermal decomposition of silane.
- Korolev,Mashirov,Perepech,Polyakov,Shil'nikov,Godisov,Kaliteevskii,Ber,Kovarskii
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- Ultrahigh growth rate of epitaxial silicon by chemical vapor deposition at low temperature with neopentasilane
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A precursor, neopentasilane, is used to produce high-quality silicon epitaxy by chemical vapor deposition under 700 °C with very high growth rates. Low background dopant concentration and excellent crystal quality were determined from secondary-ion-mass s
- Chung,Yao,Benziger,Sturm,Singh,Carlson,Kuppurao
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- Micro-Raman spectroscopy of Si nanowires: Influence of diameter and temperature
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Raman spectroscopy provides nondestructive information about nanoscaled semiconductors by modeling the phonon confinement effect. However, the Raman spectrum is also sensitive to the temperature, which can mix with the size effects borrowing the interpret
- Torres,Martin-Martin,Martinez,Prieto,Hortelano,Jimnez,Rodriguez,Sangrador,Rodriguez
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- Effect of hydrogen dilution on the structure of amorphous silicon alloys
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We investigate why high levels of hydrogen dilution of the process gas lead to enhanced light soaking stability of amorphous silicon (a-Si) alloy solar cells by studying the microstructural properties of the material using high-resolution transmission electron microscopy (TEM) and Raman spectroscopy. The TEM results show that a-Si alloy (with or without hydrogen dilution) is a heterogeneous mixture of amorphous network and linear-like objects that show evidence of order along their length. The volume fraction of these ordered regions increases with increasing hydrogen dilution.
- Tsu,Chao,Ovshinsky,Guha,Yang
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- Nanocrystal-mediated crystallization of silicon and germanium nanowires in organic solvents: The role of catalysis and solid-phase seeding
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(Figure Presented) The top seed: Various metal nanocrystals are studied as crystallization seeds for silicon and germanium nanowires. The wires are grown by decomposing silane or germane reactants in supercritical organic solvents. Co and Ni nanocrystals
- Tuan, Hsing-Yu,Lee, Doh C.,Korgel, Brian A.
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- Phosphorus doping and hydrogen passivation of donors and defects in silicon nanowires synthesized by laser ablation
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Phosphorus (P) doping was performed during the synthesis of silicon nanowires (SiNWs) by laser ablation. At least three types of signals were observed by electron spin resonance (ESR) at 4.2 K. Phosphorus doping into substitutional sites of crystalline Si in SiNWs was demonstrated by the detection of an ESR signal with a g value of 1.998, which corresponds to conduction electrons in crystalline Si, and by an energy-dispersive x-ray spectroscopy spectrum of the P Kα line. The ESR results also revealed the presence of defects. These defects were partially passivated by hydrogen and oxygen atoms.
- Fukata,Chen,Sekiguchi,Matsushita,Oshima,Uchida,Murakami,Tsurui,Ito
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- Evidence of x-ray absorption-edge shift as a function of luminescence wavelength in porous silicon
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X-ray absorption fine structure (XAFS) at the Si K edge in porous silicon has been measured by monitoring the photoluminescence yield (PLY) in different parts of the luminescence band: at increasing luminescence energy, a continuous positive shift of the x-ray absorption edge has been observed. The peculiar selectivity of the partial PLY-XAFS technique to the luminescent sites allows us to perform a size selection of the different nanostructures distributed in a single porous-silicon sample. The recombination of carriers localized in quantum confined nanocrystals is confirmed to be the main cause of the optical emission.
- Dalba,Daldosso,Fornasini,Grimaldi,Grisenti,Rocca
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- 1.5 μm luminescence of silicon nanowires fabricated by thermal evaporation of SiO
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Silicon nanowires (NWs) fabricated by thermal evaporation of SiO were studied by cathodoluminescence. A band around 1550 nm (0.8 eV) was observed. It appears above 225 K and its intensity increases with increasing temperature. The broad band consists of the defect-related D1 and D2 lines and is supposed to be formed by extended defects within the NWs that are decorated with oxygen. Moreover, luminescence bands are found that are related to Si oxide and/or the interface between Si and Si oxide. In addition, the Si band-to-band line and the G center are observed.
- Jia,Kittler,Su,Yang,Sha
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- Absolute Rate Constant for the Reaction SiH2+D2
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An absolute rate constant for the reaction of silylene with molecular deuterium at room temperature has been measured by laser resonance absorption flash kinetic spectroscopy.The rate constant is four orders of magnitude larger than previous data suggest
- Jasinski, Joseph M.
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- Synthesis of coaxial nanowires of silicon nitride sheathed with silicon and silicon oxide
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Coaxial nanowires, with about 45 nm in diameter and about 15 μm in length, have been synthesized by reaction of silicon dioxide nanoparticles with active carbon at 1450 °C in flowing nitrogen atmosphere. Their structures consist of an α-phase silicon nitride core, an amorphous silicon and a silicon dioxide outer shell, similar to those of coaxial nanocables. The formation mechanism of the coaxial nanowires is discussed.
- Wu,Song,Zhao,Huang,Pu,Sun,Du
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- Shock-induced transformation of β-Si3N4 to a high-pressure cubic-spinel phase
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β-Si3N4 powders were shock compressed and quenched from 12 to 115 GPa. β-Si3N4 transforms to the spinel-type Si3N4 (c-Si3N4) by a fast reconstructive process at pressures above about 20 GPa. The yield of c-Si3N4 recovered from 50 GPa and about 2400 K reaches about 80% and the grain sizes are about 10-50 nm. It is proposed that the fast transformation to c-Si3N4 occurs by rearrangement of nitrogen stacking layers, which initiates partial breakup of the SiN4 tetrahedra and formation of SiN6 octahedra at high density. Because of the advantages of massive production and the nanometer characteristics of shock-synthesized c-Si3N4, it is possible to investigate the mechanical properties experimentally and to develop new industrial applications.
- Sekine,He, Hongliang,Kobayashi,Zhang, Ming,Xu, Fangfang
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- Silica to silicon. Key carbothermic reactions and kinetics
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The primary carbothermic reactions for the reduction of silica to produce silicon were defined and the reaction kinetics were determined. Most possible reactions between silicon oxide and carbon or carbon compounds were studied by a series of thermogravim
- Filsinger,Bourrie
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- Silicon molecular layer epitaxy
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This paper reports on recent results of silicon molecular layer epitaxy (MLE) using SiH2Cl2 and hydrogen. Growth conditions for monomolecular layers by the monomolecular layer deposition process have been investigated as a function o
- Nishizawa,Aoki,Suzuki,Kikuchi
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- PRODUCTION OF SILICON FOR SOLAR CELLS: PRESSURE EFFECTS ON THE SiF4-Na REACTION AND ITS PRODUCTS.
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The effects of the SiF//4 pressure on the SiF//4-Na reaction and its products have been studied. Constant volume batch experiments were carried out in which Na, preheated to 250 degree C, was exposed to SiF//4 at different pressures. Because of the exothermic character of the reaction, the temperature at the reaction zone peaks to a maximum that depends on the pressure of SiF//4. At SiF//4 pressure around 1 atm, the temperature maximum reaches the highest values, near the melting point of silicon (1412 degree C). Depending on the SiF//4 pressure, three distinct reaction behaviors and corresponding reaction products can be identified. The pressure range of more interest for practical application of the SiF//4-Na reaction lies between 350 and 760 torr. At these pressures, clear segregation between the Si and NaF phases is observed and the average Si particle size is 0. 2 mm.
- SANJURJO,NANIS
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- Silicene: Wet-Chemical Exfoliation Synthesis and Biodegradable Tumor Nanomedicine
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Silicon-based biomaterials play an indispensable role in biomedical engineering; however, due to the lack of intrinsic functionalities of silicon, the applications of silicon-based nanomaterials are largely limited to only serving as carriers for drug delivery systems. Meanwhile, the intrinsically poor biodegradation nature for silicon-based biomaterials as typical inorganic materials also impedes their further in vivo biomedical use and clinical translation. Herein, by the rational design and wet chemical exfoliation synthesis of the 2D silicene nanosheets, traditional 0D nanoparticulate nanosystems are transformed into 2D material systems, silicene nanosheets (SNSs), which feature an intriguing physiochemical nature for photo-triggered therapeutics and diagnostic imaging and greatly favorable biological effects of biocompatibility and biodegradation. In combination with DFT-based molecular dynamics (MD) calculations, the underlying mechanism of silicene interactions with bio-milieu and its degradation behavior are probed under specific simulated physiological conditions. This work introduces a new form of silicon-based biomaterials with 2D structure featuring biodegradability, biocompatibility, and multifunctionality for theranostic nanomedicine, which is expected to promise high clinical potentials.
- Lin, Han,Qiu, Wujie,Liu, Jianjun,Yu, Luodan,Gao, Shanshan,Yao, Heliang,Chen, Yu,Shi, Jianlin
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Read Online
- Si nanowires synthesized by laser ablation of mixed SiC and SiO2 powders
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By using a KrF excimer laser to ablate a target of SiC powder mixed with 10 wt.% SiO2 powder at 1400°C, Si nanowires were deposited on the inner wall of a ceramic tube. Transmission electron microscopy shows that the nanowires are around 14 nm in diameter and co-exist with a small amount of nanoparticles. High-resolution transmission electron microscopy shows that the nanowires are crystalline Si nanowires and the nanoparticles are cubic SiC. The intergrowth of heterocrystal nanowires and nanoparticles verifies that the oxide-assisted growth model of Si nanowires is reasonable.
- Tang,Zhang,Peng,Wang,Lee,Lee
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Read Online
- A silicon–carbonyl complex stable at room temperature
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Main-group-element compounds with energetically high-lying donor and low-lying acceptor orbitals are able to mimic chemical bonding motifs and reactivity patterns known in transition metal chemistry, including small-molecule activation and catalytic reactions. Monovalent group 13 compounds and divalent group 14 compounds, particularly silylenes, have been shown to be excellent candidates for this purpose. However, one of the most common reactions of transition metal complexes, the direct reaction with carbon monoxide and formation of room-temperature isolable carbonyl complexes, is virtually unknown in main-group-element chemistry. Here, we show the synthesis, single-crystal X-ray structure, and density functional theory computations of a room-temperature-stable silylene carbonyl complex [L(Br)Ga]2Si:–CO (L = HC[C(Me)N(2,6-iPr2-C6H3)]2), which was obtained by direct carbonylation of the electron-rich silylene intermediate [L(Br)Ga]2Si:. Furthermore, [L(Br)Ga]2Si:–CO reacts with H2 and PBr3 with bond activation, whereas the reaction with cyclohexyl isocyanide proceeds with CO substitution. [Figure not available: see fulltext.]
- Ganesamoorthy, Chelladurai,Schoening, Juliane,W?lper, Christoph,Song, Lijuan,Schreiner, Peter R.,Schulz, Stephan
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p. 608 - 614
(2020/05/05)
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- Nucleophile induced ligand rearrangement reactions of alkoxy- and arylsilanes
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The ligand-redistribution reactions of aryl- and alkoxy-hydrosilanes can potentially cause the formation of gaseous hydrosilanes, which are flammable and pyrophoric. The ability of generic nucleophiles to initiate the ligand-redistribution reaction of commonly used hydrosilane reagents was investigated, alongside methods to hinder and halt the formation of hazardous hydrosilanes. Our results show that the ligand-redistribution reaction can be completely inhibited by common electrophiles and first-row transition metal pre-catalysts.
- Docherty, Jamie H.,Dominey, Andrew P.,Thomas, Stephen P.
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p. 3330 - 3335
(2019/05/10)
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- Dual Role of Doubly Reduced Arylboranes as Dihydrogen- and Hydride-Transfer Catalysts
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Doubly reduced 9,10-dihydro-9,10-diboraanthracenes (DBAs) are introduced as catalysts for hydrogenation as well as hydride-transfer reactions. The required alkali metal salts M2[DBA] are readily accessible from the respective neutral DBAs and Li metal, Na metal, or KC8. In the first step, the ambiphilic M2[DBA] activate H2 in a concerted, metal-like fashion. The rates of H2 activation strongly depend on the B-bonded substituents and the counter cations. Smaller substituents (e.g., H, Me) are superior to bulkier groups (e.g., Et, pTol), and a Mes substituent is even prohibitively large. Li+ ions, which form persistent contact ion pairs with [DBA]2-, slow the H2-addition rate to a higher extent than more weakly coordinating Na+/K+ ions. For the hydrogenation of unsaturated compounds, we identified Li2[4] (Me substituents at boron) as the best performing catalyst; its substrate scope encompasses Ph(H)CNtBu, Ph2CCH2, and anthracene. The conversion of E-Cl to E-H bonds (E = C, Si, Ge, P) was best achieved by using Na2[4]. The latter protocol provides facile access also to Me2Si(H)Cl, a most important silicone building block. Whereas the H2-transfer reaction regenerates the dianion [4]2- and is thus immediately catalytic, the H--transfer process releases the neutral 4, which has to be recharged by Na metal before it can enter the cycle again. To avoid Wurtz-type coupling of the substrate, the reduction of 4 must be performed in the absence of the element halide, which demands an alternating process management (similar to the industrial anthraquinone process).
- Von Grotthuss, Esther,Prey, Sven E.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
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supporting information
(2019/04/17)
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- Dual Role of Doubly Reduced Arylboranes as Dihydrogen- and Hydride-Transfer Catalysts
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Doubly reduced 9,10-dihydro-9,10-diboraanthracenes (DBAs) are introduced as catalysts for hydrogenation as well as hydride-transfer reactions. The required alkali metal salts M2[DBA] are readily accessible from the respective neutral DBAs and Li metal, Na metal, or KC8. In the first step, the ambiphilic M2[DBA] activate H2 in a concerted, metal-like fashion. The rates of H2 activation strongly depend on the B-bonded substituents and the counter cations. Smaller substituents (e.g., H, Me) are superior to bulkier groups (e.g., Et, pTol), and a Mes substituent is even prohibitively large. Li+ ions, which form persistent contact ion pairs with [DBA]2-, slow the H2-addition rate to a higher extent than more weakly coordinating Na+/K+ ions. For the hydrogenation of unsaturated compounds, we identified Li2[4] (Me substituents at boron) as the best performing catalyst; its substrate scope encompasses Ph(H)C=NtBu, Ph2C=CH2, and anthracene. The conversion of E-Cl to E-H bonds (E = C, Si, Ge, P) was best achieved by using Na2[4]. The latter protocol provides facile access also to Me2Si(H)Cl, a most important silicone building block. Whereas the H2-transfer reaction regenerates the dianion [4]2- and is thus immediately catalytic, the H--transfer process releases the neutral 4, which has to be recharged by Na metal before it can enter the cycle again. To avoid Wurtz-type coupling of the substrate, the reduction of 4 must be performed in the absence of the element halide, which demands an alternating process management (similar to the industrial anthraquinone process).
- Von Grotthuss, Esther,Prey, Sven E.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
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supporting information
p. 6082 - 6091
(2019/04/17)
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- Determination of internal residual strain induced by cryogenic thermal cycling in partially-crystalized Fe-based metallic glasses
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The intrinsic heterogeneities of the metallic glasses can be activated through cryogenic thermal cycling, making irreversible structural changes after the treatment and inducing rejuvenation to the materials. Although the energy rise after cryogenic thermal cycling can be easily determined from calorimetry, the energy change made by the heterogeneities is unknown because of the difficulty in witnessing these heterogeneities. In this paper, we investigated the changes of a typical heterogeneity: the Fe3Si crystallite, embedded in two partially-crystallized Fe-based metallic glasses, and subsequently deduced its influence on the neighbouring glassy matrix. It was found that even in the initial, partially-crystallized alloys, the Fe3Si nanocrystals were under residual expansion. Furthermore, both expansion and contraction can be detected after cryogenic thermal cycling depending on the applied number of cycles. The maximum residual volumetric strain preserved after CTC is in the order of 0.1%. Moreover, the stored energy of both crystals and glasses are calculated and the total energy rise is determined at the order of 5–50 mJ/g. The study of partially-crystallized alloys not only provides a useful model of heterogeneous materials but also reflects the structural change of the glassy phases, making this method attractive in understanding the effects of thermo-mechanical processing on heterogeneities.
- Ri,Sun,Xue,Ding,Wang
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p. 357 - 361
(2019/01/03)
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- A fleeting glimpse of the dual roles of SiB4 in promoting the hydrogen storage performance of LiBH4
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In this study, the positive effects and dual roles of SiB4 on the dehydrogenation and rehydrogenation performance of the LiBH4-SiB4 system are reported. Characterizations were performed through temperature programmed desorption mass spectrometry (TPD-MS), isothermal kinetics measurements, and XRD and FTIR analyses. For the hydrogen desorption from LiBH4, SiB4 played the role of a catalyst to kinetically facilitate the structural destabilization of LiBH4 and its intermediate phase Li2B12H12. Accordingly, a dehydrogenation capacity of 2.24 at. H/f.u. LiBH4 (close to 10.3 wt% H) was attained at a relative temperature of 350 °C. For hydrogen absorption to generate LiBH4, SiB4 was unexpectedly found to act as a reactant to thermodynamically improve the rehydrogenation process by reacting with LiH under moderate conditions of 10 MPa H2 and 400 °C, and a superior reversible capacity of 2.16 at. H/f.u. LiBH4 was achieved. These experimental results remind us to take into account the explicit role(s) of the employed components during the dehydrogenation and rehydrogenation reactions when designing a desirable LiBH4-based system.
- Cai, Weitong,Yang, Yuanzheng,Tao, Pingjun,Ouyang, Liuzhang,Wang, Hui,Yang, Xusheng
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p. 1314 - 1321
(2019/01/30)
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- Method for preparing hydrogen silane by using calcium hydride to conduct reduction on chlorosilane
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The invention discloses a method for preparing hydrogen silane by using calcium hydride to conduct reduction on chlorosilane and belongs to the technical field of chlorosilane reduction. The problemsof harsh reaction conditions, low reaction speed and the like of chlorosilane reduction through CaH2 in the prior art are solved. In an organic solvent, under catalysis of a catalyst, calcium hydrideis used as a reducing agent, and chlorosilane is reduced into hydrogen silane; the catalyst is borane or borohydride or lithium aluminum hydride, and the organic solvent is tetrahydrofuran or diethylene glycol dimethyl ether or other ether solvents. The method can be applied to hydrogen silane preparation through chlorosilane reduction.
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Paragraph 0094-0095
(2018/07/30)
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- Crystal Growth Conditions of Types i and II Na-Si Clathrates by Evaporation of Na from a Na-Si-Sn Solution
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Single crystals of the type I clathrate Na8Si46 were synthesized by the evaporation of Na from a Na-Si-Sn solution (Na:Si:Sn = 6:2:1 molar ratio) at 723-873 K under an Ar atmosphere of 105 Pa. In the mixture of type I and type II clathrates prepared by heating at 773 K for 72 h, type I single crystals with sizes of up to 5 mm were found. A single phase of single crystals of the Na24Si136 type-II clathrate having a {111} crystal facet of about 2 mm on one side was obtained by heating at 873 K for 9 h.
- Morito, Haruhiko,Shimoda, Masashi,Yamane, Hisanori,Fujiwara, Kozo
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p. 351 - 355
(2017/12/28)
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- Combustion synthesis of silicon by magnesiothermic reduction
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Magnesiothermic reduction of silica is a powerful method for producing silicon owing to its simplicity, low reduction temperature and low production cost. However, the inevitable formation of magnesium silicide (Mg2Si) limits the use of this method. A new approach was developed in this research to prevent the formation of Mg2Si by using alumina as a consumer of gaseous magnesium. Utilizing this approach, highly pure silicon was produced by firstly purifying the silica regent by acid-leaching. It was then subjected to magnesiothermic reduction regimes in order to optimize the power input and molar Mg/SiO2 ratio to minimize Mg2Si production. Silicon products were analyzed by X-ray powder diffraction (XRD) and quantitative Rietveld refinement. Optimum electrical power and molar ratio were found to be 3.75?kW and 2.25:1, respectively. The silicon product was examined by glow discharge mass spectrometry which indicated that its purity was 99.96%, with 0.10?ppm of B and 0.15?ppm of P, making it an attractive material for solar cell generation.
- Haouli, Saida,Boudebane, Said,Slipper, Ian J.,Lemboub, Samia,G?bara, Piotr,Mezrag, Samiha
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p. 280 - 287
(2018/02/06)
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- Selflating synthesis of silicon nanorods from natural sepiolite for high-performance lithium-ion battery anodes
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Nanostructured silicon is an attractive anode material for next-generation lithium-ion batteries, but its commercialization remains a challenge owing to the energy-intensive, costly, and complex preparation of nanostructured silicon. Herein, one-dimensional (1D) silicon nanorods (SNRs) have been synthesized from natural sepiolite by a simple selflating synthesis method. The intrinsic crystal structure and chemical composition of sepiolite allow for the maintenance of 1D structures during magnesiothermic reduction without any additional templates and heat scavengers. The as-prepared SNRs showed a large specific surface area (~122 m2 g-1) and hierarchical porous structure (i.e., macro- A nd meso-pores). As anodes for lithium-ion batteries, SNRs exhibited a high reversible capacity of 1350 mA h g-1 at 1.0 A g-1 after 100 cycles, and 816 mA h g-1 at 5.0 A g-1 after 500 cycles (with a capacity retention of 98%). With a low-cost precursor and facile approach, this strategy for synthesizing 1D nanostructured Si would be promising in practical production of high-performance anode materials for lithium-ion batteries.
- Chen, Qingze,Zhu, Runliang,Liu, Shaohong,Wu, DIngcai,Fu, Haoyang,Zhu, Jianxi,He, Hongping
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p. 6356 - 6362
(2018/04/23)
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- Direct electrochemical preparation of nanostructured silicon carbide and its nitridation behavior
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Silicon carbide was synthesized from mixtures of SiO2 and graphite by applying the concept of the FFC-Cambridge process and several fundamental aspects of the synthesis route were investigated. Porous disks composed of powders of SiO2 and graphite in molar ratios of 1:0.5, 1:1 and 1:1.5 were prepared by sintering in inert atmosphere and subjected to electro-deoxidation in molten CaCl2 at 1173 K under a range of experimental conditions. Disks of molar ratio 1:1.5, reduced at an applied voltage of 2.8 V for a duration of 6 h, yielded exclusively phase-pure SiC of nanowire morphology as the reaction product, while the other precursor compositions provided significant amounts of calcium silicides. Voltages lower than 2.8 V gave mixtures of SiC with elemental Si and graphite, and voltages higher than that gave CaSi alone. Shorter electro-deoxidation times led to incomplete reduction and allowed for the identification of CaSiO3 as a transient phase. Based on the experimental results a multipath reaction mechanism is proposed, consisting of the electrochemical reduction of SiO2 and CaSiO3 to Si and the subsequent in-situ carbonization of the Si formed to SiC. The effect of N2 at high temperature on the electrochemically synthesized SiC was investigated and the formation of nanowire Si2N2O was observed. Overall, the process presented is a facile single-step and low-temperature method for the synthesis of SiC with possible commercial prospects.
- Vishnu, D. Sri Maha,Sure, Jagadeesh,Kim, Hyun-Kyung,Kim, Ji-Young,Kumar, R. Vasant,Schwandt, Carsten
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p. D731 - D742
(2019/01/03)
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- Carbon coated mesoporous Si anode prepared by a partial magnesiothermic reduction for lithium-ion batteries
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Owing to its high theoretical capacity, Si based anode materials have been regarded as the most promising alternative anode materials for lithium-ion batteries. Unfortunately, the commercial application of Si based anode materials has been greatly hindered, due to the large volume change of Si materials during their lithiation/delithiation process, which results in severe pulverization, loss of electrical contact and rapid capacity fading. To address these issues, we reported a partial magnesiothermic reduction method by adjusting the proportion of added Mg powder to convert SiO2 into Si/SiO2 and subsequently to coat such a composite with a carbon layer. After removing unreacted SiO2 using HF, carbon-coated mesoporous Si (p-Si@C) can be obtained. The internal pores could accommodate the volume changes of Si and the carbon coating layer could effectively stabilize the interface during cycling. With this design, the as-prepared p-Si@C shows superior electrochemical performance compared with bare Si. When the p-Si@C electrode evaluated at a rate of 0.5?A?g?1, a reversible capacity of 1146?mAh g?1 could still be maintained after 100 cycles.
- Wu, Lili,Zhou, Haochen,Yang, Juan,Zhou, Xiangyang,Ren, Yongpeng,Nie, Yang,Chen, Song
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p. 204 - 209
(2017/05/15)
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- Enabling and Probing Oxidative Addition and Reductive Elimination at a Group 14 Metal Center: Cleavage and Functionalization of E-H Bonds by a Bis(boryl)stannylene
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By employing strongly σ-donating boryl ancillary ligands, the oxidative addition of H2 to a single site SnII system has been achieved for the first time, generating (boryl)2SnH2. Similar chemistry can also be achieved for protic and hydridic E-H bonds (N-H/O-H, Si-H/B-H, respectively). In the case of ammonia (and water, albeit more slowly), E-H oxidative addition can be shown to be followed by reductive elimination to give an N- (or O-)borylated product. Thus, in stoichiometric fashion, redox-based bond cleavage/formation is demonstrated for a single main group metal center at room temperature. From a mechanistic viewpoint, a two-step coordination/proton transfer process for N-H activation is shown to be viable through the isolation of species of the types Sn(boryl)2·NH3 and [Sn(boryl)2(NH2)]- and their onward conversion to the formal oxidative addition product Sn(boryl)2(H)(NH2).
- Protchenko, Andrey V.,Bates, Joshua I.,Saleh, Liban M. A.,Blake, Matthew P.,Schwarz, Andrew D.,Kolychev, Eugene L.,Thompson, Amber L.,Jones, Cameron,Mountford, Philip,Aldridge, Simon
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p. 4555 - 4564
(2016/05/09)
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- Apparatus and method for the condensed phase production of trisilylamine
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The present invention is directed to a condensed phase batch process for synthesis of trisilylamine (TSA). An improved synthesis process that incorporates a solvent to help promote a condensed-phase reaction between ammonia gas (or liquid) and liquified monochlorosilane (MCS) in good yields is described. This process facilitates the removal of the byproduct waste with little to no reactor down time, substantial reduction of down-stream solids contamination and high-purity product from first-pass distillation.
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Page/Page column 9-11
(2016/10/17)
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- Formal SiH4 chemistry using stable and easy-to-handle surrogates
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Monosilane (SiH4) is far less well behaved than its carbon analogue methane (CH4). It is a colourless gas that is industrially relevant as a source of elemental silicon, but its pyrophoric and explosive nature makes its handling and use challenging. Consequently, synthetic applications of SiH4 in academic laboratories are extremely rare and methodologies based on SiH4 are underdeveloped. Safe and controlled alternatives to the substituent redistribution approaches of hydrosilanes are desirable and cyclohexa-2,5-dien-1-ylsilanes where the cyclohexa-1,4-diene units serve as placeholders for the hydrogen atoms have been identified as potent surrogates of SiH4. We disclose here that the commercially available Lewis acid tris(pentafluorophenyl)borane, B(C6F5)3, is able to promote the release of the Si-H bond catalytically while subsequently enabling the hydrosilylation of C-C multiple bonds in the same pot. The net reactions are transition-metal-free transfer hydrosilylations with SiH4 as a building block for the preparation of various hydrosilanes.
- Simonneau, Antoine,Oestreich, Martin
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p. 816 - 822
(2015/10/05)
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- Fabrication and characterization of thermoelectric CrSi2 compound by mechanical alloying and spark plasma sintering
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A mixture of elemental Cr-Si powders has been subjected to mechanical alloying (MA) at room temperature to prepare CrSi2 thermoelectric compound.The MA powders were sintered at 800-1000?°C Cunder 60 MPa using spark plasma sintering (SPS) technique. Due to the observed larger loss of Si relative Cr during ball milling, the starting composition was modified to Cr30Si70, Cr31.5Si68.5 and Cr33Si67 to get a single phase of CrSi2 compound. The single phase CrSi2 has been obtained by MA of Cr31.5Si68.5 mixture powders for 70 h and subsequently sintered at 1000?°C. X-ray diffraction data shows that the SPS compact sintered at 1000?°C consists of only nanocrystalline CrSi2 compound with a grain size of 250 nm. The value of Seebeck coefficient of CrSi2 compound increases with temperature and reaches maximum value of 245 ??V/K at 300?°C.
- Lee, Chung-Hyo
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p. 5070 - 5073
(2015/03/03)
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- Silicon nanoparticles by the oxidation of [Si4]4-- and [Si9]4--containing Zintl phases and their corresponding yield
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The Zintl phases with nominal compositions Na4Si4, Rb7NaSi8, and A12Si17 (A = K, Rb, Cs) were utilized as precursors in the synthesis of silicon nanoparticles (Si NPs). The present study characterizes and compares the yields of Si NPs synthesized from Na4Si4, Rb7NaSi8, and A12Si17 (A = K, Rb, Cs). Na4Si4 and Rb7NaSi8 Zintl phases consist of anionic silicon tetrahedra stabilized by group I cations. The A12Si17 (A = K, Rb, Cs) Zintl phases that contain [Si9]4- and [Si4]4- clusters have been speculated to be more soluble than the A4Si4 (A = Na, Rb, Cs) Zintl phases that contain solely [Si4]4- clusters due to the lower charge density of the [Si9]4- cluster. The Zintl phases were reacted with NH4Br in dimethylformamide (DMF) and subsequently capped with allylamine. The Si NPs were characterized by transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), UV-vis, and photoluminescence (PL) spectrophotometry. Furthermore, the Si yields were characterized by inductively coupled plasma mass spectrometry (ICP-MS) to evaluate if the reactions of [Si9]4- cluster containing Zintl phases resulted in higher yields of Si NPs. The yield of Si increased with larger or mixed alkali metal Zintl phases, leading to the conclusion that Coulombic interactions between the cations and anions affect the Zintl phase's reactivity. The size of the Si NPs also increased with larger and mixed alkali metal cations, resulting in similar NP concentrations regardless of the starting material. With respect to ease of synthesis and yield, Na4Si4 remains the most practical precursor for the solution synthesis of Si NPs; however, the larger and mixed alkali metal precursors show promise for further development.
- Nolan, Bradley M.,Henneberger, Thomas,Waibel, Markus,F?ssler, Thomas F.,Kauzlarich, Susan M.
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p. 396 - 401
(2015/03/04)
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- Alkaline-Earth-Metal-Induced Liberation of Rare Allotropes of Elemental Silicon and Germanium from N-Heterocyclic Metallylenes
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The synthesis and striking reactivity of the unprecedented N-heterocyclic silylene and germylene ("metallylene") alkaline-earth metal (Ae) complexes of the type [(η5-C5Me5)2Ae←:E(NtBuCH)2] (3, 4, and 7-9; Ae = Ca, E = Ge 3; Ae = Sr, E = Ge 4; Ae = Sr, E = Si 7; Ae = Ba, E = Si 8; Ae = Ba, E = Ge 9) are reported. All complexes have been characterized by spectroscopic means, and their bonding situations investigated by density functional theory (DFT) methods. Single-crystal X-ray diffraction analyses of examples revealed relatively long Si-Ae and Ge-Ae distances, respectively, indicative of weak E:→Ae (E = Si, Ge) dative bonds, further supported by the calculated Wiberg bond indices, which are rather low in all cases (~0.5). Unexpectedly, the complexes undergo facile transformation to 1,4-diazabuta-1,3-diene Ae metal complexes of the type [(η5-C5Me5)2Ae(κ2-{NtBu = CHCH = NtBu})] (Ae = Sr 10, Ae = Ba 11) or in the case of calcium to the dinuclear complex [(η5-C5Me5)2Ca←:N(tBu) = CHCH = (tBu)N:→Ca(η5-C5Me5)2] (12) under concomitant liberation of elemental silicon and germanium. The formation of elemental silicon and germanium is proven by inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy, selected area electron diffraction, and energy dispersive X-ray spectroscopy. Notably, the decomposition of the Si(II)→Ba complex 8 produces allo-silicon, a rare allotropic form of elemental silicon. Similarly, the analogous Ge(II)→Ba complex 9, upon decomposition, forms tetragonal germanium, a dense and rare allotrope of elemental germanium. The energetics of this unprecedented alkaline-earth-metal-induced liberation of elemental silicon and germanium was additionally studied by DFT methods, revealing that the transformations are pronouncedly exergonic and considerably larger for the N-heterocyclic germylene complexes than those of the corresponding silicon analogues. (Figure Presented).
- Blom, Burgert,Said, Amro,Szilvási, Tibor,Menezes, Prashanth W.,Tan, Gengwen,Baumgartner, Judith,Driess, Matthias
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supporting information
p. 8840 - 8848
(2015/09/21)
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- Si-H and Si-C bond cleavage reactions of silane and phenylsilanes with Mo(PMe3)6: Silyl, hypervalent silyl, silane, and disilane complexes
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Mo(PMe3)6 cleaves the Si-H bonds of SiH4, PhSiH3, and Ph2SiH2 to afford a variety of novel silyl, hypervalent silyl, silane, and disilane complexes, as respectively illustrated by Mo(PMe3)4(SiH3) 2H2, Mo(PMe3)4(κ2- H2-H2SiPh2H)H, Mo(PMe3) 3(σ-HSiHPh2)H4, and Mo(PMe 3)3(κ2-H2-H2Si 2Ph4)H2. Mo(PMe3) 4(κ2-H2-H2SiPh2H)H and Mo(PMe3)3(κ2-H2-H 2Si2Ph4)H2 are respectively the first examples of complexes that feature a hypervalent κ2- H2-H2SiPh2H silyl ligand and a chelating disilane ligand, and both compounds convert to the diphenylsilane adduct, Mo(PMe3)3(σ-HSiHPh2)H4, in the presence of H2. Mo(PMe3)4(SiH 3)2H2 undergoes isotope exchange with SiD 4, and NMR spectroscopic analysis of the SiHxD 4-x isotopologues released indicates that the reaction does not occur via initial reductive elimination of SiH4, but rather by a metathesis pathway.
- Zuzek, Ashley A.,Parkin, Gerard
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p. 8177 - 8180
(2014/06/24)
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- BaRh2Si9-a new clathrate with a rhodium-silicon framework
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The semiconducting compound BaRh2Si9 is a new kind of intermetallic clathrate. It was obtained by reacting BaSi, Rh and Si at 950 °C. The crystal structure (space group C2/c; Pearson symbol mC48, a = 6.2221(5) A, b = 21.399(2) A, c = 6.2272(5) A, β = 90.306(7)°) displays a covalently bonded Rh-Si framework, in which four-connected Si atoms partly show unusually small bond angles. The Ba atoms are encapsulated in large polyhedral cages formed by 18 Si and 4 Rh atoms. The compound is a diamagnetic p-type semiconductor, which is in agreement with band structure calculations resulting in a band gap of 0.12 eV. Quantum chemical calculations reveal positively charged Ba atoms (Ba+1.3) and negatively charged Rh atoms (Rh-1). Si atoms with neighboring Rh atoms are positively charged, while those connected only with Si atoms are negatively charged.
- Jung, Walter,Ormeci, Alim,Schnelle, Walter,Nguyen, Hong Duong,Baitinger, Michael,Grin, Yuri
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p. 2140 - 2146
(2014/01/17)
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- Low temperature chemical reduction of fusional sodium metasilicate nonahydrate into a honeycomb porous silicon nanostructure
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Honeycomb porous silicon (hp-Si) has been synthesized by a low temperature (200 °C) magnesiothermic reduction of Na2SiO3· 9H2O. This process can be regarded as a general synthesis method for other silicide materials. Significantly, hp-Si features excellent electrochemical properties after graphene coating. the Partner Organisations 2014.
- Liang, Jianwen,Wei, Denghu,Lin, Ning,Zhu, Youngchun,Li, Xiaona,Zhang, Jingjing,Fan, Long,Qian, Yitai
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supporting information
p. 6856 - 6859
(2014/06/23)
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- Preparation of reduced iron powder using combined distribution of wood-charcoal by microwave heating
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In this paper, the influences of microwave heating with wood-charcoal as the reducing agent, on the reducing characterization of mill-scale were systematically investigated. The microstructures of the samples were characterized before and after microwave
- Ye, Qianxu,Zhu, Hongbo,Zhang, Libo,Ma, Ji,Zhou, Li,Liu, Peng,Chen, Jian,Chen, Guo,Peng, Jinhui
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p. 102 - 106
(2014/07/08)
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- Si/mesoporous carbon composite as an anode material for lithium ion batteries
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A novel synthesis of Si/mesoporous carbon (MC) composite is investigated in this work, as well as its lithium storage ability as an anode material. Nanosized Si particles are deposited in the pores of carbon matrix via magnesiothermic reduction, the content of Si is around 43 wt.% in the composite. The electrochemical performance of the composite electrode is effectively improved due to the buffering effect of carbon matrix and its Si-embedded structure. It exhibits an initial reversible capacity of 1220.9 mA h g -1, and an modified cycleability having the capacity of 594 mA h g-1 in the 50th cycle. Additionally, the good rate capability of the electrode can be ascribed to the rich porous channels and the good conductive network of mesoporous carbon.
- Shen, Xueyang,Mu, Daobin,Chen, Shi,Xu, Bin,Wu, Borong,Wu, Feng
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- Structural and mechanistic investigation of a cationic hydrogen-substituted ruthenium silylene catalyst for alkene hydrosilation
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The cationic ruthenium silylene complex [Cp*(iPr 3P)Ru(H)2(SiHMes)][CB11H6Br 6], a catalyst for olefin hydrosilations with primary silanes, was isolated and characterized by X-ray crystallography. Relatively strong interactions between the silylene Si atom and Ru-H hydride ligands appear to reflect a highly electrophilic silicon center. The mechanism of olefin hydrosilation was examined by kinetics measurements and other experiments to provide the first experimentally determined mechanism for the catalytic cycle. This mechanism involves a fast, initial addition of the Si-H bond of the silylene complex to the olefin. Subsequent elimination of the product silane produces an unsaturated intermediate, which can be reversibly trapped by olefin or intercepted by the silane substrate. The latter reaction pathway involves activation of the reactant silane by Si-H oxidative addition and α-hydrogen migration to regenerate the key silylene intermediate.
- Fasulo, Meg E.,Lipke, Mark C.,Tilley, T. Don
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p. 3882 - 3887
(2013/09/23)
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- Production of silicon from magnesium silicide
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Kinetic methods and thermogravimetry were used to study the oxidation process of magnesium silicide in air in the temperature range 300-1000 C. The reaction products were identified by X-ray phase analysis. It was found that the reaction occurs in the tem
- Borshchev,D'Yachenko,Kiselev,Kraidenko
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p. 493 - 497
(2013/07/05)
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- METHOD FOR THE PRODUCTION OF SILICON FROM SILYL HALIDES
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The present invention relates to a method for the production of silicon from silyl halides. In a first step, the silyl halide is converted, with the generation of a plasma discharge, to a halogenated polysilane, which is subsequently decomposed to silicon, in a second step, with heating.
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Page/Page column 4
(2012/06/18)
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- Kinetic modeling of low temperature epitaxy growth of SiGe using disilane and digermane
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Low temperature epitaxy (LTE) in Chemical Vapor Deposition (CVD) refers to 350-650°C interval. This temperature range is critical for this process since the thermal and lattice mismatch (or strain relaxation) issues diminish in advanced BiCMOS processing. The modeling of the epitaxy process is a vital task to increase the understanding the growth process and to design any desired device structure. In this study, an empirical model for Si2H 6/Ge2H6-based LTE of SiGe is developed and compared with experimental work. The model can predict the number of free sites on Si surface, growth rate of Si and SiGe, and the Ge content at low temperatures. A good agreement between the model and the experimental data is obtained.
- Kolahdouz,Salemi,Moeen,Oestling,Radamson
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p. H478-H481
(2012/06/04)
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- Facile preparation of silicon hollow spheres and their use in electrochemical capacitive energy storage
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Nanostructured silicon hollow spheres with a thin shell have been synthesized by magnesium reduction of silica spheres, which possess a high BET surface area and are electrochemically active in capacitive energy storage with a maximum specific capacitance of 193 F g-1 in the neutral Na 2SO4 aqueous solution. The Royal Society of Chemistry 2012.
- Liu, Mei-Pin,Li, Cheng-Hui,Du, Hong-Bin,You, Xiao-Zeng
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p. 4950 - 4952
(2012/06/01)
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- High ON/OFF ratio and multimode transport in silicon nanochains field effect transistors
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We have observed multimode transport and high ON/OFF ratio in silicon nanochain devices. Silicon nanochains grown by thermal evaporation of SiO solid sources consisted of chains of silicon nanocrystals ~10 nm in diameter, separated by SiO2 regi
- Rafiq,Masubuchi,Durrani,Colli,Mizuta,Milne,Oda
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- Silicon electrodeposition in molten fluorides
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Silicon nucleation process was investigated in molten NaF-KF (40-60 mol%) on silver electrodes in the 820-950 °C temperature range in order to optimize silicon coating operating conditions. Chronoamperometric measurements evidenced that silicon electrodeposition process involved an instantaneous nucleation with diffusion-controlled nuclei growth whatever temperature and Si(IV) ions concentration in the mixture. The overpotential and temperature influence on nucleation sites number was also studied. Silicon deposits were obtained using the same temperature range as nucleation study, for different current densities on substrates: Ni, Ag, Cgraphite and C vitreous. A sensitive influence of the cathodic substrate on the deposit adherence and roughness was observed and discussed.
- Bieber,Massot,Gibilaro,Cassayre,Taxil,Chamelot
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p. 282 - 289
(2012/03/12)
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- Hydrogen-terminated silicon nanowire photocatalysis: Benzene oxidation and methyl red decomposition
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Hydrogen-terminated silicon nanowires (H-SiNWs) were used as heterogeneous photocatalysts for the hydroxylation of benzene and for the decomposition of methyl red under visible light irradiation. The above reactions were monitored by GC-MS and UV-Vis spectrophotometry, respectively, which shows 100% selectivity for the transformation of benzene to phenol. A complete decomposition of a 2 × 10-4 M methyl red solution was achieved within 30 min. The high selectivity for the hydroxylation of benzene and the photodecomposition demonstrate the catalytic activity of ultrafine H-SiNWs during nanocatalysis.
- Lian, Suoyuan,Tsang, Chi Him A.,Kang, Zhenhui,Liu, Yang,Wong, Ningbew,Lee, Shuit-Tong
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p. 2441 - 2444
(2012/01/04)
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- Galvanic deposition of nanoporous Si onto 6061 Al alloy from aqueous HF
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We report galvanic deposition of Si onto 6061 Al alloy from dilute aqueous hydrofluoric acid (HF) at pH 2.5. The overall reaction involves reduction of SiF62- to Si with simultaneous oxidation and dissolution of Al. The Si film is ab
- Krishnamurthy, Aarti,Rasmussen, Don H.,Suni, Ian I.
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- Silicon nanowire fabric as a lithium ion battery electrode material
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A nonwoven fabric with paperlike qualities composed of silicon nanowires is reported. The nanowires, made by the supercritical-fluid-liquid-solid process, are crystalline, range in diameter from 10 to 50 nm with an average length of >100 μm, and are coated with a thin chemisorbed polyphenylsilane shell. About 90% of the nanowire fabric volume is void space. Thermal annealing of the nanowire fabric in a reducing environment converts the polyphenylsilane coating to a carbonaceous layer that significantly increases the electrical conductivity of the material. This makes the nanowire fabric useful as a self-supporting, mechanically flexible, high-energy-storage anode material in a lithium ion battery. Anode capacities of more than 800 mA h g-1 were achieved without the addition of conductive carbon or binder.
- Chockla, Aaron M.,Harris, Justin T.,Akhavan, Vahid A.,Bogart, Timothy D.,Holmberg, Vincent C.,Steinhagen, Chet,Mullins, C. Buddie,Stevenson, Keith J.,Korgel, Brian A.
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p. 20914 - 20921
(2012/02/04)
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- Formation of impurity Si2OH6 in silane synthesized from silicon tetrafluoride
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The possibility of the reduction of hexafluorodisiloxane by calcium hydride in the synthesis of silane from silicon tetrafluoride has been studied. This reaction is shown to be not decisive for oxygen contamination of silane. The most likely reason for the appearance of impurity Si2OH6 in "fluoride" silane is the Ca(OH)2-catalyzed reaction of silane with trace water. The concentration of impurity Si2OH 6 in silane at the stage of synthesis may be efficiently decreased by the preliminary purging of calcium hydride with a hydrogen (grade A) flow.
- Bulanov,Sennikov,Sozin, A. Yu.,Lashkov, A. Yu.,Troshin, O. Yu.
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p. 510 - 512
(2011/07/29)
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- Corrosion of structural ceramics under sub-critical conditions in aqueous sodium chloride solution and in deionized water. Part II: Dissolution of Al 2O3-based ceramics
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Two types of alumina-based ceramics, pure solid-state sintered (SSS) alumina ceramics, and a liquid phase sintered (LPS) alumina were corrosion tested under both static and quasi-dynamic conditions in 0.5M NaCl solution and in deionized water reference medium at the temperature of 290°C. Static tests were also performed at 150° and 200°C in order to obtain the data for determination of kinetic parameters, and for calculation of the activation energies. The apparent activation energies of dissolution of the LPS alumina in deionized water and in 0.5M NaCl solution were identical and ranged around 49 kJ/mol. The SSS alumina ceramics corroded by grain-boundary attack and slow dissolution of alumina matrix grains, and the corrosion rates were negligible in both corrosion media. The LPS alumina, corroded by preferential attack and dissolution of calcium aluminosilicate grain-boundary glass. The alumina matrix remained relatively intact. The dissolution was markedly faster than in the SSS alumina. The rates of dissolution were found to be temperature dependent, but no influence of the corrosion medium was observed.
- Galuskova, Dagmar,Hnatko, Miroslav,Galusek, Dusan,Sajgalik, Pavol
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p. 3044 - 3052
(2012/01/12)
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- Phase separation and Si nanocrystal formation in bulk SiO studied by x-ray scattering
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We present an x-ray scattering study of the temperature-induced phase separation and Si nanocrystal formation in bulk amorphous SiOx with x≈1. X-ray Raman scattering at the Si LII,III -edge reveals a significant contribution of suboxides present in native amorphous SiO. The suboxide contribution decreases with increasing annealing temperature between 800-1200 °C pointing toward a phase separation of SiO into Si and SiO2 domains. In combination with x-ray diffraction and small angle x-ray scattering the SiO microstructure is found to be dominated by internal suboxide interfaces in the native state. For higher annealing temperatures above 900 °C growth of Si nanocrystals with rough surfaces embedded in a silicon oxide matrix can be observed.
- Feroughi,Sternemann,Sahle,Schroer,Sternemann,Conrad,Hohl,Seidler,Bradley,Fister,Balasubramanian,Sakko,Pirkkalainen,Haemaelaeinen,Tolan
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- Mechanically activated synthesis of monosilane by the reaction of calcium hydride with silicon tetrafluoride
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Possibility of performing a mechanically activated synthesis of pure monosilane by the reaction of calcium hydride with silicon tetrafluoride in a rotating flow-through reactor containing milling bodies was analyzed. A number of operation parameters of the grinding reactor were theoretically evaluated and experimentally determined.
- Troshin, O. Yu.,Bulanov,Mikheev,Lashkov, A. Yu.
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p. 984 - 988
(2011/01/10)
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- Electrochemical behavior of nanoporous/nanofibrous Si anode materials prepared by mechanochemical reduction
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A mixture of nanoporous and nanofibrous silicon (NPNF-Si) is prepared by the mechanochemical reduction of SiCl4 using Li13Si4 as reducing agent in the presence of Super P carbon (SP) and the following thermal treatment and washing process. Morphologies and structures of the as-obtained composites are investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). After carbon coating via pyrolysis of polyvinyl chloride (PVC), the resulting NPNF-Si/SP/C composite is evaluated for the use as anode material in lithium-ion battery. It exhibits the first discharge capacity of 746.6 mAh g-1 at current density of 0.2 mA mg-1 and capacity retention of 91.1% after 30 cycles. The good electrochemical performance arises from the particular Si nano-structure, which can alleviate the volume effect during lithium insertion and extraction.
- Lv, Rongguan,Yang, Jun,Gao, Pengfei,NuLi, Yanna,Wang, Jiulin
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- Effects of ultrasonic vibration on the iron-containing intermetallic compounds of high silicon aluminum alloy with 2% Fe
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The effects of ultrasonic vibration (USV), the combined effects of USV and the addition of Mn on the morphology of iron-containing intermetallic compounds of Al-20Si-2.0Fe-2.0Cu-0.4Mg-1.0Ni alloy have been studied respectively. The mechanism of shape-transformation of Fe-containing phases is also investigated. A large amount of long needle-like β-Al5FeSi phases accompanied with a few δ-Al4FeSi2 phases existed in the matrix of high silicon aluminum alloy with 2% Fe in traditional casting process. The effects of acoustic cavitation and acoustic streaming generated by USV which was applied near the liquidus temperature of this alloy, homogenized the solute distribution field and temperature field of the melt, lowered the concentration level of Fe atoms in solidification front, and decreased the start-freezing temperature of β phase. That the formation of acicular β phase was suppressed, contribute to enlarge the forming temperature range of δ phase of the alloy with certain time of USV imposed near the liquidus temperature. The finest δ particles and only a small amount of β phase were obtained in the matrix of the Fe-containing alloy with USV for 120 s. With the complex effects of USV and addition of 0.5% Mn, the forming of acicular β phase was almost repressed and the Fe-containing phases were in forms of fine Al4(Fe,Mn)Si2 and Al5(Fe,Mn)Si particles in the size of 20-30 μm. Crown Copyright
- Zhong, Gu,Wu, Shusen,Jiang, Huawen,An, Ping
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p. 482 - 487
(2010/06/14)
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- Low-temperature solid phase epitaxy for integrating advanced source/drain metal-oxide-semiconductor structures
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We show that chemical vapor deposition using trisilane decomposition opens capabilities for the deposition of amorphous silicon on Si substrate at low temperature. Based on this behavior we developed a process including amorphous silicon deposition and crystallization. Transmission electron microscopy observations prove that solid phase epitaxy (SPE) occurs and produces monocrystalline layers, free of extended defects and compatible with complementary metal-oxide-semiconductor technology. We also show that during SPE films remain amorphous on oxidized areas while they transform into single crystal on Si. This process opens promising perspectives for the fabrication of advanced MOS structures.
- Gouy,Berbezier,Favre,Amiard,Aouassa,Campidelli,Halimaoui
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- Temperature programmed desorption studies of deuterium passivated silicon nanocrystals
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As grown silicon (Si) surfaces are known to reconstruct in order to reduce the number of dangling bonds. Surface reconstructions of hydride-terminated Si(1 0 0) and Si(1 1 1) surfaces have already been extensively studied using temperature programmed deso
- Salivati, Navneethakrishnan,Ekerdt, John G.
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p. 1121 - 1125
(2009/08/15)
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- Synthesis of nanosized silicon particles by a rapid metathesis reaction
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A solid-state rapid metathesis reaction was performed in a bed of sodium silicofluoride (Na2SiF6) and sodium azide (NaN3) powders diluted with sodium fluoride (NaF), to produce silicon nanoparticles. After a local ignition
- Won,Nersisyan,Won,Lee
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p. 3201 - 3206
(2010/04/04)
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- Synthesis of polysilanes by tunneling reactions of H atoms with solid Si2H6 at 10K
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Tunneling reactions of H atoms with solid Si2H6 at 10K were investigated. The in situ and real-time reactions H + Si 2H6 to form silane and polysilanes were monitored using FT-IR. Quantitative analysis of gaseou
- Sogoshi, Norihito,Sato, Shoji,Takashima, Hideaki,Sato, Tetsuya,Hiraoka, Kenzo
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p. 986 - 987
(2012/09/22)
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- Controlled thermal decomposition of NaSi to derive silicon clathrate compounds
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Formation conditions of two types of sodium containing silicon clathrate compounds were determined by the controlled thermal decomposition of sodium monosilicide NaSi under vacuum. The decomposition began at 360 °C. Much higher decomposition temperatures
- Horie, Hiro-omi,Kikudome, Takashi,Teramura, Kyosuke,Yamanaka, Shoji
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p. 129 - 135
(2009/04/14)
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