Wir anerkennen Paul JL Webster für die 3D-Rendering von optischen Daten mit Amira. Phil Muñoz und Benjamin Franta Rückmeldungen auf das Manuskript im Laufe seiner Entwicklung. Die Forschung in diesem Papier beschrieben wurde von der Air Force Office of Scientific Research unter Zuschüsse FA9550-09-1 bis 0546 und FA9550-10-1 bis 0402 unterstützt.

Ein. Herstellung von Metall-Ionen dotierter Polymerfilm <ol><li> Messen Sie 8 ml Wasser in einem Becherglas. </li><li> Hinzufügen 206 mg PVP zu Wasser. Mix mit Magnetrührer oder Vortex-Mixer, bis die Lösung klar ist. </li><li> Fügen Sie 210 mg AgNO 3 zur Lösung. Mix mit Magnetrührer oder Vortex-Mixer, bis die Lösung klar ist. </li><li> Coat Glasplatte mit Lösung durch Drop Casting. </li><li> Glasobjektträger Ort im Ofen eingestellte bei 100 ° C Backen Probe für 30 min. </li><li> Wägegut vom Ofen und lassen für 30 Minuten kühl. </li></ol> 2. Herstellung von Disconnected Silber Structures <ol><li> Richten Sie Setup in Abbildung 1 auf optischen Tisch mit Schwingungsisolatoren dargestellt. </li><li> Passen Kompressor 50-fs Impulse nach Mikroskopobjektiv erhalten. </li><li> Passen Neutralfilter bis 3-nJ Impulse nach dem Ziel zu erhalten. </li><li> Stellen Sie sicher, Messfleck ist größer als Rückapertur der Mikroskop-Objektiv. </li><li>Set akustooptischen Modulator bis 10-usec Belichtungsfenster, während der die Probe bestrahlt wird erzeugen. </li><li> Block Laserstrahl vor Erreichen des Mikroskops und Ort Probe auf 3-Achsen-Verschiebungselement. Der Strahlengang der Femtosekunden-Laserpulsen sollte durch die Bildgebung Mikroskopobjektiv und in die Probe gelangen. </li><li> Schalten Mikroskop Beleuchtungsquelle, um die Probe in situ unter Verwendung CCD-Kamera zu beobachten. </li><li> Übersetzen z-Achse der Stufe zur Grenzfläche zwischen Glassubstrat und Polymerfilm finden. Dann refokussieren Mikroskops auf die gewünschte Tiefe im Inneren Polymers zum Mustern untersten Schicht. Z-Translation während Strukturieren muss in der Richtung weg von dem Glas-Polymer-Schnittstelle sein, um Streuung mit gefertigten Strukturen zu vermeiden. </li><li> Unblock Laserstrahl-und Set Motion-Controller-Software zur Probe in x übersetzen -, y - und z - Richtung mit einer Geschwindigkeit von 100 mu m / sec. Bestrahlen einzigen Voxel für 10 usec einernd getrennte benachbarte Voxel durch wenigstens einigen Mikrometern für klare In-situ-Bildgebung. Einstellen akustooptischen Modulator Wiederholungsrate bis 25 Hz produziert 4-Abstand um. Laser belichteten Bereichen wird Silber enthalten Strukturen. </li></ol>

<ol>
	<li>von Freymann, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-Dimensional+Nanostructures+for+Photonics.">Three-Dimensional Nanostructures for Photonics.</a> Advanced Functional Materials. 20, 1038-1052 (2010).</li><li>LaFratta, C. N., Fourkas, J. T., Baldacchini, T., Farrer, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiphoton+Fabrication.">Multiphoton Fabrication.</a> Angewandte Chemie International Edition. 46, 6238-6258 (2007).</li><li>Gattass, R. R., Mazur, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Femtosecond+laser+micromachining+in+transparent+materials.">Femtosecond laser micromachining in transparent materials.</a> Nat. Photon. 2, 219-225 (2008).</li><li>Li, L., Gattass, R. R., Gershgoren, E., Hwang, H., Fourkas, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Achieving+&#955;/20+Resolution+by+One-Color+Initiation+and+Deactivation+of+Polymerization.">Achieving &#955;/20 Resolution by One-Color Initiation and Deactivation of Polymerization.</a> Science. 324, 910-913 (2009).</li><li>Haske, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=65+nm+feature+sizes+using+visible+wavelength+3-D+multiphoton+lithography.">65 nm feature sizes using visible wavelength 3-D multiphoton lithography.</a> Opt. Express. 15, 3426-3436 (2007).</li><li>Xing, J. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+spatial+resolution+of+two-photon+microfabrication+by+using+photoinitiator+with+high+initiating+efficiency.">Improving spatial resolution of two-photon microfabrication by using photoinitiator with high initiating efficiency.</a> Appl. Phys. Lett. 90, 131106 (2007).</li><li>Tan, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+in+feature+size+of+two-photon+polymerization+using+SCR500.">Reduction in feature size of two-photon polymerization using SCR500.</a> Appl. Phys. Lett. 90, 071106 (2007).</li><li>Vora, K., Kang, S., Shukla, S., Mazur, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+disconnected+three-dimensional+silver+nanostructures+in+a+polymer+matrix.">Fabrication of disconnected three-dimensional silver nanostructures in a polymer matrix.</a> Appl. Phys. Lett. 100, 063120 (2012).</li><li>G&#252;ney, D. &. #. 2. 1. 4. ;., Koschny, T., Soukoulis, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intra-connected+three-dimensionally+isotropic+bulk+negative+index+photonic+metamaterial.">Intra-connected three-dimensionally isotropic bulk negative index photonic metamaterial.</a> Opt. Express. 18, 12348-12353 (2010).</li><li>Grigorenko, A. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanofabricated+media+with+negative+permeability+at+visible+frequencies.">Nanofabricated media with negative permeability at visible frequencies.</a> Nat. Photon. 438, 335-338 (2005).</li><li>Grigorenko, A. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Negative+refractive+index+in+artificial+metamaterials.">Negative refractive index in artificial metamaterials.</a> Opt. Lett. 31, 2483-2485 (2006).</li><li>Shalaev, V. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Negative+index+of+refraction+in+optical+metamaterials.">Negative index of refraction in optical metamaterials.</a> Opt. Lett. 30, 3356-3358 (2005).</li><li>Ishikawa, A., Tanaka, T., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+excitation+of+magnetic+resonance+in+metamaterials+at+far-infrared+frequencies.">Magnetic excitation of magnetic resonance in metamaterials at far-infrared frequencies.</a> Appl. Phys. Lett. 91, 113118 (2007).</li><li>Tanaka, T., Ishikawa, A., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-photon-induced+reduction+of+metal+ions+for+fabricating+three-dimensional+electrically+conductive+metallic+microstructure.">Two-photon-induced reduction of metal ions for fabricating three-dimensional electrically conductive metallic microstructure.</a> Appl. Phys. Lett. 88, 081107 (2006).</li><li>Ishikawa, A., Tanaka, T., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvement+in+the+reduction+of+silver+ions+in+aqueous+solution+using+two-photon+sensitive+dye.">Improvement in the reduction of silver ions in aqueous solution using two-photon sensitive dye.</a> Appl. Phys. Lett. 89, 113102 (2006).</li><li>Cao, Y. -. Y., Takeyasu, N., Tanaka, T., Duan, X. -. M., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+Metallic+Nanostructure+Fabrication+by+Surfactant-Assisted+Multiphoton-Induced+Reduction.">3D Metallic Nanostructure Fabrication by Surfactant-Assisted Multiphoton-Induced Reduction.</a> Small. 5, 1144-1148 (2009).</li></ol>

Keine Interessenskonflikte erklärt.

Der Schlüssel für den Prozess wird Erhalten eines dotierten dielektrischen Matrix, die Hochauflösung Fertigung ermöglicht, aber nicht bald nach der Herstellung verschlechtern. Eine einfache Mischung aus PVP, AgNO 3 und H 2 O ermöglicht die Erstellung von hochauflösenden Silber Nanostrukturen, die in einem Support-Matrix eingebettet sind. Variieren des PVP an AgNO 3-Verhältnis ändert die Laserenergie für die Herstellung erforderlich, und möglicherweise andere Eigenschaften wie M...

a method to fabricate disconnected silver nanostructures in 3d

Der Standard Nanofabrikation Toolkit umfasst Techniken in erster Linie an die Erstellung von 2D-Muster in dielektrischen Medien abzielen. Erstellen Metall Muster auf einem Submikrometerbereich erfordert eine Kombination von Nanofabrikation Tools und mehrere Material Verarbeitungsschritte. Zum Beispiel, Schritte zum Erstellen planaren Metall-Strukturen mit UV Photolithographie und Elektronenstrahl-Lithographie können Sample Exposition, Probe Entwicklung, Metallabscheidung und Metall liftoff gehören. Um 3D-Metall-Strukturen zu schaffen, wird die Sequenz mehrere Male wiederholt. Die Komplexität und die Schwierigkeit, Stapeln und Ausrichten mehreren Schichten begrenzt praktische Implementierungen von 3D-Metall-Strukturierung mit Standard Nanofabrikation Tools. Femtosekunden-Laser-Direkt-Schreiben als eine herausragende Technik für 3D Nanofabrikation entstanden. 1,2 Femtosekunden-Laser werden häufig verwendet, um 3D-Muster in Polymeren und Gläsern zu schaffen. 3-7 jedoch, 3D Metall-direct-Schreiben bleibt eine Herausforderung. Hier haben wirbeschreiben ein Verfahren zu Silber Nanostrukturen in einer Polymermatrix mit einem Femtosekunden-Laser bei 800 nm zentriert eingebetteten herzustellen. Das Verfahren ermöglicht die Herstellung von Mustern nicht durchführbar unter Verwendung anderer Techniken, wie z. B. 3D-Arrays getrennt Silber Voxeln. 8 Disconnected 3D Metallstrukturen sind Metamaterialien wo Elementarzellen sind nicht in Kontakt miteinander, 9 wie gekoppelten Metalls dot 10 nützlich, 11 oder gekoppelten Metallstab 12,13 Resonatoren. Potenzielle Anwendungen sind negativer Index Metamaterialien, Unsichtbarkeitsmäntel und perfekte Linsen. Im Femtosekunden-Laser-Direkt-Schreibens wird die Laserwellenlänge gewählt, dass Photonen nicht linear in das Zielmedium absorbiert. Wenn der Laser Impulsdauer zur Femtosekundenzeitskala komprimiert und die Strahlung dicht innerhalb des Targets fokussiert, induziert die extrem hohe Intensität nichtlinearen Absorption. Mehrere Photonen absorbiert gleichzeitigely, um elektronische Übergänge, die wesentliche Änderung im Fokus Region führen verursachen. Mit diesem Ansatz kann ein Strukturen in der Masse eines Materials, anstatt auf seiner Oberfläche zu bilden. Die meiste Arbeit auf 3D direkte Metall-Schreibgeräte hat auf die Schaffung self-supported Metall Strukturen. 14-16 Die hier beschriebene Methode ergibt Sub-Mikrometer-silber Strukturen, die nicht brauchen, um sich selbst nicht unterstützt, da sie innerhalb einer Matrix eingebettet sind. Dotiertes Polymermatrix hergestellt wird unter Verwendung einer Mischung von Silbernitrat (AgNO 3), Polyvinylpyrrolidon (PVP) und Wasser (H 2 O). Die Proben werden dann durch Bestrahlung mit einem 11-MHz Femtosekundenlaser Herstellung 50-fs-Pulse gemustert. Während der Bestrahlung wird Photoreduktion von Silberionen durch nichtlineare Absorption induziert, wodurch ein Aggregat von Silber-Nanopartikeln im Fokusbereich. Mit diesem Ansatz schaffen wir silberne Muster in einem dotierten PVP-Matrix eingebettet. Hinzufügen von 3D-Übersetzung des sausreichend erweitert die Strukturierung auf drei Dimensionen.

Der akustooptische Modulator und Neutralfilter (Abbildung 1) erlauben, die Menge an Energie, hinterlegt in der Probe zu steuern. Verwendung einer Belichtung von 110 Impulsen pro Voxel und 3 nJ pro Impuls, wobei die Stufe der Übersetzung bei 100 um / sec, sind die resultierenden Strukturen Silber leicht sichtbar durch die in-situ optischen Mikroskop. Niedrigere Laser Exposition (durch Verringerung Pulsenergie und / oder Impulszahl) führen zu kleineren Silber Merkmale;. Wir Merkmalen so klein w...

Watch this Scientific Journal Video about A Method to Fabricate Disconnected Silver Nanostructures in 3D at JoVE.com

A Method to Fabricate Disconnected Silver Nanostructures in 3D

Femtosekunden-Laser-Direkt-Schreiben wird häufig verwendet, um dreidimensionale (3D) Strukturen in Polymeren und Gläsern zu schaffen. Allerdings bleibt Strukturierung Metallen in 3D eine Herausforderung. Wir beschreiben ein Verfahren zum Herstellen Silber Nanostrukturen in einer Polymermatrix durch einen Femtosekunden-Laser bei 800 nm zentriert eingebettet.

Ein Verfahren zur Getrennt Silber Nanostrukturen in 3D Fabricate

The standard nanofabrication toolkit includes  techniques primarily aimed at creating 2D patterns in dielectric media. Creating  metal patterns on a ...

a-method-to-fabricate-disconnected-silver-nanostructures-in-3d

Research

JoVE Journal

Engineering

13.7K Aufrufe.  Harvard University. Femtosekunden-Laser-Direkt-Schreiben wird häufig verwendet, um dreidimensionale (3D) Strukturen in Polymeren und Gläsern zu schaffen. Allerdings bleibt Strukturierung Metallen in 3D eine Herausforderung. Wir beschreiben ein Verfahren zum Herstellen Silber Nanostrukturen in einer Polymermatrix durch einen Femtosekunden-Laser bei 800 nm zentriert eingebettet.

Serie: A Method to Fabricate Disconnected Silver Nanostructures in 3D

High-resolution, High-speed, Three-dimensional Video Imaging with Digital Fringe Projection Techniques

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses triangulation between matching points in two views of the same scene at different angles to compute depth.&#160;However, unlike a stereo-based method, DFP uses a digital video projector to replace one of the cameras1. The projector rapidly projects a known sinusoidal pattern onto the subject, and the surface of the subject distorts these patterns in the camera&#8217;s field of view. Three distorted patterns (fringe images) from the camera can be used to compute the depth using triangulation.
Unlike other 3D measurement methods, DFP techniques lead to systems that tend to be faster, lower in equipment cost, more flexible, and easier to develop.&#160;DFP systems can also achieve the same measurement resolution as the camera.&#160;For this reason, DFP and other digital structured light techniques have recently been the focus of intense research (as summarized in1-5). Taking advantage of DFP, the graphics processing unit, and optimized algorithms, we have developed a system capable of 30&#160;Hz 3D video data acquisition, reconstruction, and display for over 300,000 measurement points per frame6,7.&#160;Binary defocusing DFP methods can achieve even greater speeds8.
Diverse applications can benefit from DFP techniques. Our collaborators have used our systems for facial function analysis9, facial animation10, cardiac mechanics studies11, and fluid surface measurements, but many other potential applications exist.&#160;This video will teach the fundamentals of DFP techniques and illustrate the design and operation of a binary defocusing DFP system.

This video describes the fundamentals of digital fringe projection techniques, which provide dense 3D measurements of dynamically changing surfaces.&#160;It also demonstrates the design and operation of a high-speed binary defocusing system based on these techniques.

High-Auflösung, High-Speed-, Three-dimensional Imaging mit Digital-Video-Streifenprojektionstechnik

Digital fringe projection (DFP) techniques provide dense 3D measurements of dynamically changing surfaces.&#160;Like the human eyes and brain, DFP uses ...

Forschung

Ingenieurwesen

Evaluating Plasmonic Transport in Current-carrying Silver Nanowires

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information support1,2,3. In this context, metal nanowires are especially desirable for realizing dense routing networks4. A prerequisite to operate such shared nanowire-based platform relies on our ability to electrically contact individual metal nanowires and efficiently excite surface plasmon polaritons5 in this information support. In this article, we describe a protocol to bring electrical terminals to chemically-synthesized silver nanowires6 randomly distributed on a glass substrate7. The positions of the nanowire ends with respect to predefined landmarks are precisely located using standard optical transmission microscopy before encapsulation in an electron-sensitive resist. Trenches representing the electrode layout are subsequently designed by electron-beam lithography. Metal electrodes are then fabricated by thermally evaporating a Cr/Au layer followed by a chemical lift-off. The contacted silver nanowires are finally transferred to a leakage radiation microscope for surface plasmon excitation and characterization8,9. Surface plasmons are launched in the nanowires by focusing a near infrared laser beam on a diffraction-limited spot overlapping one nanowire extremity5,9. For sufficiently large nanowires, the surface plasmon mode leaks into the glass substrate9,10. This leakage radiation is readily detected, imaged, and analyzed in the different conjugate planes in leakage radiation microscopy9,11. The electrical terminals do not affect the plasmon propagation. However, a current-induced morphological deterioration of the nanowire drastically degrades the flow of surface plasmons. The combination of surface plasmon leakage radiation microscopy with a simultaneous analysis of the nanowire electrical transport characteristics reveals the intrinsic limitations of such plasmonic circuitry.

Silver nanowires can simultaneously transport electrons and optical information in the form of surface plasmons. A procedure is described here to realize such a shared circuitry and the limitations at propagating both information carriers are evaluated.

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information ...

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

Schreiben und Niedertemperatur-Charakterisierung von Nanostrukturen

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial resolution, and is even capable of providing atomically resolved elemental maps. In this technique, a highly focused electron beam is incident upon a thin sample and the energy of emitted X-rays is measured in order to determine the atomic species of material within the beam path. This elementally sensitive spectroscopy technique can be extended to three dimensional tomographic imaging by acquiring multiple spectrum images with the sample tilted along an axis perpendicular to the electron beam direction.
Elemental distributions within single nanoparticles are often important for determining their optical, catalytic and magnetic properties. Techniques such as X-ray tomography and slice and view energy dispersive X-ray mapping in the scanning electron microscope provide elementally sensitive three dimensional imaging but are typically limited to spatial resolutions of &gt; 20 nm. Atom probe tomography provides near atomic resolution but preparing nanoparticle samples for atom probe analysis is often challenging. Thus, elementally sensitive techniques applied within the scanning transmission electron microscope are uniquely placed to study elemental distributions within nanoparticles of dimensions 10-100 nm.
Here, energy dispersive X-ray (EDX) spectroscopy within the STEM is applied to investigate the distribution of elements in single AgAu nanoparticles. The surface segregation of both Ag and Au, at different nanoparticle compositions, has been observed.

The use of energy dispersive X-ray tomography in the scanning transmission electron microscope to characterize elemental distributions within single nanoparticles in three dimensions is described.

Energieröntgentomografie für 3D-Elementar Zuordnung einzelner Nanopartikel

Energy dispersive X-ray spectroscopy within the scanning transmission electron microscope (STEM) provides accurate elemental analysis with high spatial ...

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor performance, which suggest a new direction for the development of next-generation ultrathin and flexible photonic and electronic devices. Enhanced luminescence quantum efficiency has been widely observed in these atomically thin 2D crystals. However, dimension effects beyond quantum confinement thicknesses or even at the micrometer scale are not expected and have rarely been observed. In this study, molybdenum diselenide (MoSe2) layer crystals with a thickness range of 6-2,700 nm were fabricated as two- or four-terminal devices. Ohmic contact formation was successfully achieved by the focused-ion beam (FIB) deposition method using platinum (Pt) as a contact metal. Layer crystals with various thicknesses were prepared through simple mechanical exfoliation by using dicing tape. Current-voltage curve measurements were performed to determine the conductivity value of the layer nanocrystals. In addition, high-resolution transmission electron microscopy, selected-area electron diffractometry, and energy-dispersive X-ray spectroscopy were used to characterize the interface of the metal&#8211;semiconductor contact of the FIB-fabricated MoSe2 devices. After applying the approaches, the substantial thickness-dependent electrical conductivity in a wide thickness range for the MoSe2-layer semiconductor was observed. The conductivity increased by over two orders of magnitude from 4.6 to 1,500 &#937;&#8722;1 cm&#8722;1, with a decrease in the thickness from 2,700 to 6 nm. In addition, the temperature-dependent conductivity indicated that the thin MoSe2 multilayers exhibited considerably weak semiconducting behavior with activation energies of 3.5-8.5 meV, which are considerably smaller than those (36-38 meV) of the bulk. Probable surface-dominant transport properties and the presence of a high surface electron concentration in MoSe2 are proposed. Similar results can be obtained for other layer semiconductor materials such as MoS2 and WS2.

We describe the approaches for the device fabrication and electrical characterization of molybdenum diselenide (MoSe2) layer semiconductor nanostructures with different thicknesses. In addition, the fabrication of ohmic contacts for MoSe2-layer nanocrystals by the focused-ion beam deposition method using platinum (Pt) as a contact metal is described.

Ohmsche Kontakt Fabrication unter Verwendung eines fokussierten Ionenstrahl-Technik und Elektrische Charakterisierung für Layer-Halbleiter-Nanostrukturen

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

Integration of Light Trapping Silber-Nanostrukturen in Hydrogenated Microcrystalline Silicon Solar Cells durch Transferdruck

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing technology is used to fabricate particles with slender arms connected at a common center. Shapes explored are crosses (two perpendicular rods), jacks (three perpendicular rods), triads (three rods in triangular planar symmetry), and tetrads (four arms in tetrahedral symmetry). Methods for producing on the order of 10,000 fluorescently dyed particles are described. Time-resolved measurements of their orientation and solid-body rotation rate are obtained from four synchronized videos of their motion in a turbulent flow between oscillating grids with R&#955; = 91. In this relatively low-Reynolds number flow, the advected particles are small enough that they approximate ellipsoidal tracer particles. We present results of time-resolved 3D trajectories of position and orientation of the particles as well as measurements of their rotation rates.

We use 3D printing to fabricate anisotropic particles in the shapes of jacks, crosses, tetrads, and triads, whose alignments and rotations in turbulent fluid flow can be measured from multiple simultaneous video images.

Verfahren zur Messung der Neigung und Drehrate von 3D-gedruckten Particles in Turbulence

Experimental methods are presented for measuring the rotational and translational motion of anisotropic particles in turbulent fluid flows. 3D printing ...

A Fabrication Method for Highly Stretchable Conductors with Silver Nanowires

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of stretchable electronic devices is the preparation of stretchable conductors with great mechanical stability. In this study, we developed a simple fabrication method to chemically solder the contact points between silver nanowire (AgNW) networks. AgNW nanomesh was first deposited on a glass slide via spray coating method. A reactive ink composed of silver nanoparticle (AgNPs) precursors was applied over the spray coated AgNW thin films. After heating for 40 min, AgNPs were preferentially generated over the nanowire junctions to solder the AgNW nanomesh, and reinforced the conducting network. The chemically modified AgNW thin film was then transferred to polyurethane (PU) substrates by casting method. The soldered AgNW thin films on PU exhibited no obvious change in electrical conductivity under stretching or rolling process with elongation strains up to 120%.

A simple synthesis method is used to chemically solder silver nanowire thin film to fabricate highly stretchable and conductive metal conductors.

Ein Herstellungsverfahren für hochverstreckbare Leiter mit Silber Nanodrähte

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of ...

Challenges in Rheological Characterization of Highly Concentrated Suspensions &#8212; A Case Study for Screen-printing Silver Pastes

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the manifold requirements during processing and application of such complex fluids. In this investigation, measuring protocols for a conclusive assessment of different process relevant rheological parameters have been evaluated. This includes the determination of yield stress, viscosity, wall slip velocity, structural recovery after large deformation and elongation at break as well as tensile force during filament stretching.
The importance of concomitant video recordings during parallel-plate rotational rheometry for a significant determination of rheological quantities is demonstrated. The deformation profile and flow field at the sample edge can be determined using appropriate markers. Thus, measurement parameter settings and plate roughness values can be identified for which yield stress and viscosity measurements are possible. Slip velocity can be measured directly and measuring conditions at which plug flow, shear banding or sample spillover occur can be identified clearly. 
Video recordings further confirm that the change in shear moduli observed during three stage oscillatory shear tests with small deformation amplitude in stage I and III but large oscillation amplitude in stage II can be directly attributed to structural break down and recovery. For the pastes investigated here, the degree of irreversible, shear-induced structural change increases with increasing deformation amplitude in stage II until a saturation is reached at deformations corresponding to the crossover of G' and G'', but the irreversible damage is independent of the duration of large amplitude shear. 
A capillary breakup elongational rheometer and a tensile tester have been used to characterize deformation and breakup behavior of highly filled pastes in uniaxial elongation. Significant differences were observed in all experiments described above for two commercial screen-printing silver pastes used for front side metallization of Si-solar cells.

A protocol for a robust and application relevant rheological characterization of highly concentrated suspensions is presented. Silver pastes used for screen-printing application in solar cell production are employed as model systems.

Herausforderungen in rheologische Charakterisierung von hochkonzentrierten Suspensionen - Eine Fallstudie für Serigrafie Silberpasten

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the ...

A Standard and Reliable Method to Fabricate Two-Dimensional Nanoelectronics

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D materials is still in nascent stages, scientists cannot fully rely on traditional semiconductor techniques for related research. Delicate processes from locating the materials to electrode definition need to be well controlled. In this article, a universal fabrication protocol required in manufacturing nanoscale electronics, such as 2D quasi-heterojunction bipolar transistors (Q-HBT), and 2D back-gated transistors are demonstrated. This protocol includes the determination of material position, electron beam lithography (EBL), metal electrode definition, et al. A step by step narrative of the fabrication procedures for these devices are also presented. Furthermore, results show that each of the fabricated devices has achieved high performance with high repeatability. This work reveals a comprehensive description of process flow for preparing 2D nano-electronics, enables the research groups to access this information, and pave the way toward future electronics.

The article aims to introduce a standard and reliable fabrication procedure for the development of future low dimensional nanoelectronics.

Eine Standard und zuverlässige Methode, zweidimensionale Nanoelektronik zu fabrizieren

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D ...