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Surfaces with silver nanostructures are useful, due to their potential to resonate strongly with visible light. This report demonstrates a process for the directed extraction of silver at the surface of a transparent superionic conductor. A focused electron beam incident on superionic AgIAgPO3 glass results in localized negative charge deposition, which is neutralized by the electrochemical reduction of free silver ions. This process was characterized for beam energies ranging from 1 to 12 kV and primary beam fluence ranging from 50 pC μm−2 to 35 nC μm−2. For electron fluence less than 2.5 nC μm−2 the process produces vibrant coloration of the glass which can be tuned throughout the entire visible spectrum. Fluence greater than 2.5 nC μm−2 results in the controlled writing of bulk silver on the surface, with a minimum line width as small as 400 nm and narrow gaps as small as 50 nm. The high ionic conductivity of the substrate is shown to be a vital component to the process, allowing the wide range of colors to be produced along with the controlled, nondendritic growth of silver structures.

Theoretical analyses of a set of iterated-tour partitioning vehicle routing algorithms applicable to a wide variety of commonly used vehicle routing problem variants are presented. We analyze the worst-case performance of the algorithms and establish tightness of the derived bounds. Among other variants, we capture the cases of pick-up and delivery and multiple depots. We also introduce brand new concepts such as mobile depots, partitioning of customer nodes into groups, and potential opportunistic under-utilization of vehicle capacity by only partially loading the vehicle, among others, which arise from a printed circuit board application. The problems studied are of critical importance in many practical applications. © 2012 Wiley Periodicals, Inc. NETWORKS, 2013

Active, programmable control of interfacial adhesion is an important, desired feature of many existing and envisioned systems, including medical tapes, releasable joints, and stamps for transfer printing. Here a design for an elastomeric surface that offers switchable adhesion strength through a combination of peel-rate dependent effects and actuation of sub-surface fluid chambers is presented. Microchannels and open reservoirs positioned under a thin surface membrane can be pressurized in a controlled manner to induce various levels of surface deformation via inflation. These pressurized structures demonstrate utility in controllably decreasing the strength of adhesion of flat, solid objects to the elastomeric surface, particularly in the limit of low peel-rates. Experimental and theoretical studies of these systems reveal the key mechanisms, and guide optimized geometries for broad control over adhesion, in a programmable and reversible manner. Implementing these concepts in stamps for transfer printing enables new modes for deterministic assembly of micro- and nanoscale materials onto diverse types of substrates. Collections of silicon plates delivered onto plastic, paper and other surfaces with single or multiply addressable stamps illustrate some of the capabilities.

In this paper we present mechanics and materials aspects of elastomeric stamps that have angled features of relief on their surfaces, designed to enable control of adhesion strength by peeling direction, in a way that can be exploited in schemes for deterministic assembly by transfer printing. Detailed mechanics models capture the essential physics of interface adhesion in this system. Experiments with cylindrical stamps that have this design demonstrate their potential for use in a continuous, roller mode of operation.

Self-similar Sierpinski carpet fractals were fabricated using a new nanopatterning technique, i.e. solid-state superionic stamping (S4), to study the effect of feature size on plasmon-enhanced Raman scattering. A real-time Raman image showing electromagnetic (EM) field enhancement contrast is demonstrated. The effects were studied and explained in the context of modes of surface plasmon excitation. Additionally, we find that the EM field enhancement supported by the fractals extends further spatially as compared to continuous Ag surfaces. Copyright © 2010 John Wiley & Sons, Ltd.

This article demonstrates a method for fabricating high quality single-crystal silicon ribbons, platelets and bars with dimensions between ∼100 nm and ∼5 cm from bulk (111) wafers by using phase shift and amplitude photolithographic methods in conjunction with anisotropic chemical etching procedures. This “top-down” approach affords excellent control over the thicknesses, lengths, and widths of these structures and yields almost defect-free, monodisperse elements with well defined doping levels, surface morphologies and crystalline orientations. Dry transfer printing these elements from the source wafers to target substrates by use of soft, elastomeric stamps enables high yield integration onto wafers, glass plates, plastic sheets, rubber slabs or other surfaces. As one application example, bottom gate thin-film transistors that use aligned arrays of ribbons as the channel material exhibit good electrical properties, with mobilites as high as ∼200 cm 2 V –1 s –1 and on/off ratios >10 4 .

Multijunction (MJ) solar cells have the potential to operate across the entire solar spectrum, for ultrahigh efficiencies in light to electricity conversion. Here an MJ cell architecture is presented that offers enhanced capabilities in photon recycling and photon extraction, compared to those of conventional devices. Ideally, each layer of a MJ cell should recycle and re-emit its own luminescence to achieve the maximum possible voltage. This design involves materials with low refractive indices as interfaces between sub-cells in the MJ structure. Experiments demonstrate that thin-film GaAs devices printed on low-index substrates exhibit improved photon recycling, leading to increased open-circuit voltages (V oc), consistent with theoretical predictions. Additional systematic studies reveal important considerations in the thermal behavior of these structures under highly concentrated illumination. Particularly when combined with other optical elements such as anti-reflective coatings, these architectures represent important aspects of design for solar cells that approach thermodynamic efficiency limits for full spectrum operation.