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Metal Nanostructures (metal + nanostructure)

Distribution by Scientific Domains

Physics and Astronomy	50%

Selected Abstracts

Functional Nanostructured Plasmonic Materials

ADVANCED MATERIALS, Issue 10 2010
Jimin Yao
Abstract Plasmonic crystals fabricated with precisely controlled arrays of subwavelength metal nanostructures provide a promising platform for sensing and imaging of surface binding events with micrometer spatial resolution over large areas. Soft nanoimprint lithography provides a robust, cost-effective method for producing highly uniform plasmonic crystals of this type with predictable optical properties. The tunable multimode plasmonic resonances of these crystals and their ability for integration into lab-on-a-chip microfluidic systems can both be harnessed to achieve exceptionally high analytical sensitivities down to submonolayer levels using even a common optical microscope, circumventing numerous technical limitations of more conventional surface plasmon resonance techniques. In this article, we highlight some recent advances in this field with an emphasis on the fabrication and characterization of these integrated devices and their demonstrated applications. [source]

Design of Plasmonic Thin-Film Solar Cells with Broadband Absorption Enhancements

ADVANCED MATERIALS, Issue 34 2009
Ragip A. Pala
Noble metal nanostructures can enhance absorption in thin-film solar cells by simultaneously taking advantage of i) high near-fields surrounding the nanostructures close to their surface plasmon resonance frequency and ii) coupling to waveguide modes. We develop basic design rules for the realization of broadband absorption enhancements for such structures. [source]

Porous silicon/metal nanocomposite with tailored magnetic properties

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2009
Petra Granitzer
Abstract Porous silicon (PS) templates in the meso/macro porous regime with oriented pores clearly separated from each other and filled in a galvanic deposition process with various metals, especially ferromagnetic ones are magnetically investigated. The employment of different metals (e.g. Ni, Co, NiCo) together with the variation of the electrochemical deposition parameters modifies the structural characteristics of the PS/metal nanocomposite and thus leads to distinct magnetic properties of the hybrid system. Furthermore the use of different PS-templates which means a change of the pore-diameter and interpore spacing results also in various magnetic characteristics, especially influences on the magnetic interactions among the deposited metal nanostructures. Therefore the specimens show tailored magnetic properties like coercivity, squareness and magnetic anisotropy. The achieved nanocomposite merges electronic properties of a semiconductor with nanomagnetism and therefore opens the possibility of integrated spin-based electronic devices. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Unconventional control of excited states of a dimer molecule by a localized light field between metal nanostructures

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009
Takuya Iida
Abstract We have made a theoretical study of the spatial interplay between the localized light field (LLF) and the electronic wavefunction of molecules. When the LLF has a nanoscale spatial variation comparable to a molecular wavefunction, this interplay is crucial to determine the optical response of molecular excited states. Such a condition can be realized in case that a molecule is lying in the vicinity of a metal nanogap. By using the calculation method applicable to arbitrary-shaped samples, we demonstrate a drastic enhancement of the response electromagnetic field from an optical forbidden state whose magnitude is comparable to that from an allowed state. The obtained result indicates that we have a possibility to control the excited states of molecules by designing the LLF with metal nanostructures. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Waveguide-plasmon polaritons in photonic crystal slabs with metal nanowires

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2005
S. G. Tikhodeev
Abstract The optical properties of a photonic crystal slab made of periodic arrays of gold nanowires on top of different dielectric substrates, supporting and not supporting the guided modes are discussed. While only Rayleigh-type anomalies are observed for thin dielectric substrates, thicker waveguiding substrates demonstrate strong coupling phenomena. It is shown that the interaction between the quasiguided modes in the photonic crystal slab and the localised plasmons in metal nanostructures results in the formation of a strongly coupled waveguide-plasmon polariton. The formation of the new quasiparticle manifests itself in the strong anticrossing between quasiguided modes and plasmon resonances in the measured as well as calculated optical spectra. The effect opens new possibilities for photonic band gap engineering in metallic-dielectric photonic crystals. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Silver Coated Platinum Core,Shell Nanostructures on Etched Si Nanowires: Atomic Layer Deposition (ALD) Processing and Application in SERS

CHEMPHYSCHEM, Issue 9 2010
Vladimir A. Sivakov Dr.
Abstract A new method to prepare plasmonically active noble metal nanostructures on large surface area silicon nanowires (SiNWs) mediated by atomic layer deposition (ALD) technology has successfully been demonstrated for applications of surface-enhanced Raman spectroscopy (SERS)-based sensing. As host material for the plasmonically active nanostructures we use dense single-crystalline SiNWs with diameters of less than 100 nm as obtained by a wet chemical etching method based on silver nitrate and hydrofluoric acid solutions. The SERS active metal nanoparticles/islands are made from silver (Ag) shells as deposited by autometallography on the core nanoislands made from platinum (Pt) that can easily be deposited by ALD in the form of nanoislands covering the SiNW surfaces in a controlled way. The density of the plasmonically inactive Pt islands as well as the thickness of noble metal Ag shell are two key factors determining the magnitude of the SERS signal enhancement and sensitivity of detection. The optimized Ag coated Pt islands on SiNWs exhibit great potential for ultrasensitive molecular sensing in terms of high SERS signal enhancement ability, good stability and reproducibility. The plasmonic activity of the core-shell Pt//Ag system that will be experimentally realized in this paper as an example was demonstrated in numerical finite element simulations as well as experimentally in Raman measurements of SERS activity of a highly diluted model dye molecule. The morphology and structure of the core-shell Pt//Ag nanoparticles on SiNW surfaces were investigated by scanning- and transmission electron microscopy. Optimized core,shell nanoparticle geometries for maximum Raman signal enhancement is discussed essentially based on the finite element modeling. [source]