Microcrystalline silicon‐carbon alloys as anti‐reflection window layers in high efficiency thin film silicon solar cells

Microcrystalline silicon‐carbide (μc‐SiC:H) films were prepared using hot wire chemical vapor deposition at low substrate temperature. The μc‐SiC:H films were employed as window layers in microcrystalline silicon (μc‐Si:H) solar cells. The short‐circuit current density (J_SC) in these n‐side illuminated n–i–p cells increases with increasing the deposition time t_W of the μc‐SiC:H window layer from 5 min to 60 min. The enhanced J_SC is attributed to both the high transparency and an anti‐reflection effect of the μc‐SiC:H window layer. Using these favourable optical properties of the μc‐SiC:H window layer in μc‐Si:H solar cells, a J_SC value of 23.8 mA/cm² and cell efficiencies above 8.0% were achieved with an absorber layer thickness of 1 μm and a Ag back reflector. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Salts of the cobalt(I) complexes [Co(CO)5]+ and [Co(CO)2(NO)(2)]+ and the Lewis acid-base adduct [Co2(CO)7CO--B(CF3)3

The reaction of [Co(2)(CO)(8)] with (CF(3))(3)BCO in hexane leads to the Lewis acid-base adduct [Co(2)(CO)(7)CO--B(CF(3))(3)] in high yield. When the reaction is performed in anhydrous HF solution [Co(CO)(5)][(CF(3))(3)BF] is isolated. The product contains the first example of a homoleptic metal pentacarbonyl cation with 18 valence electrons and a trigonal-bipyramidal structure. Treatment of [Co(2)(CO)(8)] or [Co(CO)(3)NO] with NO(+) salts of weakly coordinating anions results in mixed crystals containing the [Co(CO)(5)](+)/[Co(CO)(2)(NO)(2)](+) ions or pure novel [Co(CO)(2)(NO)(2)](+) salts, respectively. This is a promising route to other new metal carbonyl nitrosyl cations or even homoleptic metal nitrosyl cations. All compounds were characterized by vibrational spectroscopy and by single-crystal X-ray diffraction.     

Silicene on hydrogen‐passivated Si(111) and Ge(111) substrates

By means of first‐principles calculations we predict the stability of silicene as buckled honeycomb lattice on passivated substrates of group‐IV(111)1 × 1 surfaces. The weak van‐der‐Waals interaction between silicene and substrates does not destroy its linear bands forming Dirac cones at the Brillouin zone corners. Only very small fundamental gaps are opened around the Fermi level.

     

Rare isotope beams at ISAC—target & ion source systems

The present status of the ISAC facility for rare isotopes beams after its first 10 years of operation is presented. Planning for the ISAC facility started in 1985 with the Parksville workshop on radioactive ion beams (Buchmann and D’Auria 1985). It was put on halt by the KAON proposal and planning was only resumed in 1993 after the cancellation of KAON. The ISAC facility was built to satisfy the scientific need for accelerated beams of rare isotopes for use in applications such as nuclear physics, nuclear astrophysics, atomic and condensed matter physics as well as medicine. At the time of the ISAC proposal submission, a number of facilities were either planned or under construction. In order to have an impact in the field, the requirements and specifications for the driver beam intensity on target was set to 100 μA, 500 MeV protons, which for ISAC results in a driver beam power of 50 kW.     

Reaktionen der Digalliumverbindung R2Ga–GaR2 [R = CH(SiMe3)2] mit Wasser und Carbonsäuren – Synthese von μ‐Hydroxo‐μ‐carboxylatodigallium‐Verbindungen unter Erhalt der Ga–Ga‐Bindungen

Treatment of the digallium compound R₂Ga–GaR₂ [ 1 , R = CH(SiMe₃)₂] with a broad variety of functionalized carboxylic acids in the presence of water yielded μ‐hydroxo‐μ‐carboxylatodigallium compounds ( 2 – 10 ) containing intact Ga–Ga bonds in high to moderate yields. The compounds form dimeric formula units in which the unsupported Ga–Ga bonds are bridged by two hydroxo and two carboxylato ligands. Each gallium atom is terminally coordinated by a bulky alkyl group. NMR spectroscopy revealed mixtures of two isomeric compounds in solution in all cases. The second component may show a different bridging mode with each Ga–Ga bond bridged by a bidentate carboxylato ligand to form Ga₂O₂C five‐membered heterocycles.     

Experimental and numerical investigations in skeletal muscle modelling

In the present paper, a method to compare displacement results of a muscle contraction simulation with results of optical experiments is proposed. A human skeletal muscle has been reconstructed to a volume element out of real two-dimensional MRI data. The surrounding tissue has also been taken into account in order to describe the interaction with other components in a realistic way. These regions of the interface have been supported by several spring stiffness. The numerical model has been fitted by this stiffness on one significant node. The results shown satisfied agreement with the optical experiments. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effective particle size from molecular dynamics simulations in fluids

We report molecular dynamics simulations designed to investigate the effective size of colloidal particles suspended in a fluid in the vicinity of a rigid wall where all interactions are defined by smooth atomic potential functions. These simulations are used to assess how the behavior of this system at the atomistic length scale compares to continuum mechanics models. In order to determine the effective size of the particles, we calculate the solvent forces on spherical particles of different radii as a function of different positions near and overlapping with the atomistically defined wall and compare them to continuum models. This procedure also then determines the effective position of the wall. Our analysis is based solely on forces that the particles sense, ensuring self-consistency of the method. The simulations were carried out using both Weeks–Chandler–Andersen and modified Lennard-Jones (LJ) potentials to identify the different contributions of simple repulsion and van der Waals attractive forces. Upon correction for behavior arising the discreteness of the atomic system, the underlying continuum physics analysis appeared to be correct down to much less than the particle radius. For both particle types, the effective radius was found to be \(\sim 0.75\sigma \), where \(\sigma \) defines the length scale of the force interaction (the LJ diameter). The effective “hydrodynamic” radii determined by this means are distinct from commonly assumed values of \(0.5\sigma \) and \(1.0\sigma \), but agree with a value developed from the atomistic analysis of the viscosity of such systems.