Given k pairs of terminals {(s1, t1), . . . , (sk, tk)} in a graph G, the min-sum k vertex-disjoint paths problem is to find a collection {Q1, Q2, . . . , Qk} of vertex-disjoint paths with minimum total length, where Qi is an si-to-ti path between si and ti. We consider the problem in planar graphs, where little is known about computational tractability, even in restricted cases. Kobayashi and ...

UNLABELLED We investigated hybrid inorganic-organic solar cells combining monocrystalline n-type silicon (n-Si) and a highly conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) ( PEDOT PSS). The build-in potential, photo- and dark saturation current at this hybrid interface are monitored for varying n-Si doping concentrations. We corroborate that a high build-in potent...

0021-9517/$ see front matter 2009 Elsevier Inc. A doi:10.1016/j.jcat.2009.10.015 * Corresponding author. Address: Goesmann 222, Amherst, MA 01003-9336, USA. Fax: +1 413 545 4490 E-mail addresses: [email protected] (V. Ag (G.W. Huber), [email protected] (W.C. Conner edu (S.M. Auerbach). We have performed embedded-cluster calculations using density functional theory to investigate mechan...

In this study, the geometries of the [SiNinHn]q and [SiCunHn]q clusters, (n = 4,5,6 and q = 0,+1,-1) complexes have been optimized to form complexes with four, five and six planar and nonplanarsubstituents, with negative, neutral or positive atomic charge, using Density FunctionalTheory (DFT) at B3LYP/6-311+G (3df, p) computational level and then their thermodynamicstability were investigated b...

We report comparison of lasing dynamics in InAs quantum dot (QD) micro-disk lasers (MDLs) monolithically grown on V-groove patterned and planar Si (001) substrates. TEM characterizations reveal abrupt interfaces and reduced threading dislocations in the QD active regions when using the GaAs-on-V-grooved-Si template. The improved crystalline quality translates into lower threshold power in the o...

UNLABELLED Periodic silicon nanocones (SiNCs) with different periodicities are fabricated by dry etching of a Si substrate patterned using monolayer polystyrene (PS) nanospheres as a mask. Hybrid Si/ PEDOT PSS solar cells based on the SiNCs are then fabricated and characterized in terms of their optical, electrical, and photovoltaic properties. The optical properties of the SiNCs are also inv...

A fundamental strategy to enhance optical transmission through a continuous metallic film based on strong interference dominated by interface phase shift is developed. In a metallic film coated with a thin semiconductor film, both transmission and absorption are simultaneously enhanced as a result of dramatically reduced reflection. For a 50-nm-thick Ag film, experimental transmission enhanceme...

An np-Si microwire array coupled with a two-layer catalyst film consisting of Ni–Mo nanopowder and TiO2 light-scattering nanoparticles has been used to simultaneously achieve high fill factors and lightlimited photocurrent densities from photocathodes that produce H2(g) directly from sunlight and water. The TiO2 layer scattered light back into the Si microwire array, while optically obscuring t...

A method to fabricate silicon (Si) inverse opals with diamond structure is introduced. The method is based on the arrangement of silica particles in a template consisting of Si pillars periodically distributed. The profile of the pillars is specially designed to induce the self-organized growth of the particles in a diamond lattice along the (1 1 0) direction. Afterwards, the inverse structure ...

This paper investigates mechanisms of enhanced light absorption exhibited by ultrathin Si solar microcells integrated with a periodically nanostructured, semitransparent metallic reflector. This backside reflector comprises periodic nanoscale relief features formed by soft-imprint lithography with a thin (~35 nm) coating of Au. The work shows that microcells placed in direct contact above the n...