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The ability of plasmonic metal nanostructures (PMNs), such as silver and gold nanoparticles, to manipulate and concentrate electromagnetic fields at the nanoscale is the foundation for wide range of applications, including nanoscale optics, solar energy harvesting, and photocatalysis. However, there are inherent problems associated with plasmonic metals, such as high Ohmic losses and poorer compatibility with the conventional complementary metal−oxide−semiconductor (CMOS) microfabrication processes. These limitations inhibit the broader use of PMNs in practical applications. Herein, we report submicrometer cuprous oxide (Cu 2 O) cubic particles can exhibit strong electric and magnetic Mie resonances with extinction/scattering cross sections comparable to or slightly exceeding those of Ag particles. Using size-and shape-controlling particle synthesis techniques, optical spectroscopy, and finite-difference time-domain simulations, we show that the Mie resonance wavelengths are size-and shape-dependent and tunable in the visible to near-infrared regions. Therefore, submicrometer Cu 2 O cubic particles may potentially emerge as high-performance alternatives to PMNs. The strong electric and magnetic Mie-resonance-mediated nanoantenna attribute of the Cu 2 O cubic particles can be potentially used in a wide range of applications, including nanoscale optics, surface-enhanced Raman spectroscopy, surface-enhanced infrared absorption spectroscopy, photocatalysis, and photovoltaics.

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Distinct conformational changes of single photoactive yellow protein (PYP) molecules were captured under photoexcitation, using a SERS substrate approach. These steps conform to those in PYP's photocycle. At the single molecule level, SERS of PYP yields well-resolved peaks, some of which were not reported earlier. Further, exclusive peak pairs have been identified that can elucidate PYP's conformational steps and chemisorption configuration on Ag using the SERS selection rules. Despite the "weak chemisorption" of PYP on silver that only allows the single molecule signal to sustain for approximately 1 s, this duration may be long enough to resolve PYP's photocycle (approximately 0.3 s).

Our "grow-in-place" approach to Si nanowire devices uses a silicon precursor gas (e.g., SiH 4 ) to directly produce self-assembled, electrically contacted, crystalline Si nanowires without any intervening silicon material formation or collection/positioning steps. The approach uses the vapor−liquid−solid (VLS) growth mechanism and lithographically fabricated, permanent, nanochannel growth templates to control the size, shape, orientation, and positioning of the nanowires and ribbons. These horizontal templates are an integral component of the final devices and provide contacts, interconnects, and passivation/encapsulation. The approach results in self-assembly of the Si nanowires (SiNWs) and nanoribbons (SiNRs) into interconnected devices without any "pick-and-place" or printing steps, thereby avoiding the most serious problems encountered in process control, assembly, contacting, and integration of SiNWs and SiNRs for IC applications. As an initial demonstration of our approach, we have fabricated SiNW and SiNR resistors with built-in electrical contacts and encapsulation and report conductivity measurements.

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Porous carbons, including carbon (C-) aerogels, are technologically important materials, while polyacrylonitrile (PAN) is the main industrial source of graphite fiber. Graphite aerogels are synthesized herewith pyrolytically from PAN aerogels, which in turn are prepared first by solution copolymerization in toluene of acrylonitrile (AN) with ethylene glycol dimethacrylate (EGDMA) or 1,6-hexanediol diacrylate (HDDA). Gelation is induced photochemically and involves phase-separation of "live" nanoparticles that get linked covalently into a robust 3D network. The goal of this work was to transfer that process into aqueous systems and obtain similar nanostructures in terms of particle sizes, porosity, and surface areas. That was accomplished by forcing the monomers into (micro)emulsions, in essence inducing phase-separation of virtual primary particles before polymerization. Small angle neutron scattering (SANS) in combination with location-ofinitiator control experiments support that monomer reservoir droplets feed polymerization in ∼3 nm radius micelles yielding eventually large (∼60 nm) primary particles. The latter form gels that are dried into macro-/mesoporous aerogels under ambient pressure from water. PAN aerogels by either solution or emulsion gelation are aromatized (240 °C, air), carbonized (800 °C, Ar), and graphitized (2300 °C, He) into porous structures (49−64% v/v empty space) with electrical conductivities >5× higher than those reported for other C-aerogels at similar densities. Despite a significant pyrolytic loss of matter (up to 50−70% w/w), samples shrink conformally (31−57%) and remain monolithic. Chemical transformations are followed with CHN analysis, 13 C NMR, XRD, Raman, and HRTEM. Materials properties are monitored by SEM and N 2 -sorption. The extent and effectiveness of interparticle connectivity is evaluated by quasi-static compression. Overall, irrespective of the gelation method, PAN aerogels and the resulting carbons are identical materials in terms of their chemical composition and microstructure. Although cross-linkers EGDMA and HDDA decompose completely by 800 °C, surprisingly their signature in terms of different surface areas, crystallinity, and electrical conductivities is traced in all the pyrolytic products.