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Nanowire Arrays (nanowire + array)
Kinds of Nanowire Arrays Selected AbstractsPerfectly Ordered, Free-Standing Nanowire Arrays With Controllable Geometry,ADVANCED ENGINEERING MATERIALS, Issue 11 2009Adam Philip Robinson We demonstrate a novel focused ion beam (FIB) based technique for the production of substrate-supported, free-standing, perfectly ordered nanowire arrays with control over the pore geometry, pitch, diameter, and length. A FIB may be used to influence the site of pore formation in ultra-thin (<1 µm) oxide nanoporous templates adhered to substrates. Electrodeposition through the template results in the production of nanowire arrays with controlled, perfect ordering. [source] Mesoporous Systems for the Preparation of Ordered Magnetic Nanowire Arrays,ADVANCED ENGINEERING MATERIALS, Issue 4 2005A. Eliseev Some tendencies in data storage technologies based on magnetic nanostructures are discussed and a novel approach to anisotropic magnetic nanoparticles which can be used as an active components of magnetic storage media is proposed by the authors [source] A General Approach for Fabricating Arc-Shaped Composite Nanowire Arrays by Pulsed Laser DepositionADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Yue Shen Abstract Here, a new method is demonstrated that uses sideways pulsed laser deposition to deliberately bend nanowires into a desired shape after growth and fabricate arc-shaped composite nanowire arrays of a wide range of nanomaterials. The starting nanowires can be ZnO, but the materials to be deposited can be metallic, semiconductor, or ceramic depending on the application. This method provides a general approach for rational fabrication of a wide range of side-by-side or "core,shell" nanowire arrays with controllable degree of bending and internal strain. Considering the ZnO is a piezoelectric and semiconductive material, its electrical properties change when deformed. This technique has potential applications in tunable electronics, optoelectronics, and piezotronics. [source] Light-Emitting Rubrene Nanowire Arrays: A Comparison with Rubrene Single CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Jin Woo Lee Abstract This is a report on a new method of growth of a light-emitting rubrene nanowires array with diameters of 200,±,10,nm by using organic vapor transport through Al2O3 nanoporous templates. Nanometer-scale laser confocal microscope (LCM) photoluminescence (PL) spectra and crystalline structures of the rubrene nanowires are compared with those of rubrene single crystals prepared with the same experimental conditions without the template. In the LCM PL spectra it is observed that the PL spectra and intensity varies with the detecting positions because of the crystal growth characteristics of the rubrene molecules. A single rubrene nanowire has a wider LCM PL band width than that of the rubrene single crystal. This may originate from the light emissions of the mixed polarized bands due to additional new crystallinity in the formation of the nanowires. From the current,voltage characteristic curves, the semiconducting nature of both the rubrene nanowires and single crystals is observed. [source] Large-Area Silver-Coated Silicon Nanowire Arrays for Molecular Sensing Using Surface-Enhanced Raman Spectroscopy,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2008Baohua Zhang Abstract A new and facile method to prepare large-area silver-coated silicon nanowire arrays for surface-enhanced Raman spectroscopy (SERS)-based sensing is introduced. High-quality silicon nanowire arrays are prepared by a chemical etching method and used as a template for the generation of SERS-active silver-coated silicon nanowire arrays. The morphologies of the silicon nanowire arrays and the type of silver-plating solution are two key factors determining the magnitude of SERS signal enhancement and the sensitivity of detection; they are investigated in detail for the purpose of optimization. The optimized silver-coated silicon nanowire arrays exhibit great potential for ultrasensitive molecular sensing in terms of high SERS signal enhancement ability, good stability, and reproducibility. Their further applications in rapidly detecting molecules relating to human health and safety are discussed. A 10 s data acquisition time is capable of achieving a limit of detection of approximately 4,×,10,6M calcium dipicolinate (CaDPA), a biomarker for anthrax. This value is 1/15 the infectious dose of spores (6,×,10,5,M required), revealing that the optimized silver-coated silicon nanowire arrays as SERS-based ultrasensitive sensors are extremely suitable for detecting Bacillus anthracis spores. [source] Synthesis and Lasing Properties of Highly Ordered CdS Nanowire Arrays,ADVANCED FUNCTIONAL MATERIALS, Issue 9 2007L. Cao Abstract Highly ordered large-area arrays of wurtzite CdS nanowires are synthesized on Cd-foil substrates via a simple liquid reaction route using thiosemicarbazide and Cd foil as the starting materials. The CdS nanowires are single crystals growing along the [001],direction and are perpendicular to the surface of the substrate. The characteristic Raman peaks of CdS are red-shifted and show asymmetric broadening, which is ascribed to phonon confinement effects arising from the nanoscale dimensions of the nanowires. Significantly, the uniform CdS nanowire arrays can act as laser cavities in the visible-light range, leading to bandgap lasing at ca.,515,nm with obvious modes. The high density of nuclei and the preferential growth direction induce the formation of aligned CdS nanowires on the metal substrate. [source] Hierarchical Shelled ZnO Structures Made of Bunched Nanowire Arrays,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2007P. Jiang Abstract The size- and morphology-controlled growth of ZnO nanowire (NW) arrays is potentially of interest for the design of advanced catalysts and nanodevices. By adjusting the reaction temperature, shelled structures of ZnO made of bunched ZnO NW arrays are prepared, grown out of metallic Zn microspheres through a wet-chemical route in a closed Teflon reactor. In this process, ZnO NWs are nucleated and subsequently grown into NWs on the surfaces of the microspheres as well as in strong alkali solution under the condition of the pre-existence of zincate (ZnO22,) ions. At a higher temperature (200,°C), three different types of bunched ZnO NW or sub-micrometer rodlike (SMR) aggregates are observed. At room temperature, however, the bunched ZnO NW arrays are found only to occur on the Zn microsphere surface, while double-pyramid-shaped or rhombus-shaped ZnO particles are formed in solution. The ZnO NWs exhibit an ultrathin structure with a length of ca.,,500,nm and a diameter of ca.,10,nm. The phenomenon may be well understood by the temperature-dependent growth process involved in different nucleation sources. A growth mechanism has been proposed in which the degree of ZnO22,saturation in the reaction solution plays a key role in controlling the nucleation and growth of the ZnO NWs or SMRs as well as in oxidizing the metallic Zn microspheres. Based on this consideration, ultrathin ZnO NW cluster arrays on the Zn microspheres are successfully obtained. Raman spectroscopy and photoluminescence measurements of the ultrathin ZnO NW cluster arrays have also been performed. [source] Well-Aligned ZnO Nanowire Arrays Fabricated on Silicon Substrates ,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2004C. Geng Abstract Arrays of well-aligned single-crystal zinc oxide (ZnO) nanowires of uniform diameter and length have been synthesized on a (100) silicon substrate via a simple horizontal double-tube system using chemical vapor transport and condensation method. X-ray diffraction and transmission electron microscopy (TEM) characterizations showed that the as-grown nanowires had the single-crystal hexagonal wurtzite structure with detectable defects and a <0002> growth direction. Raman spectra revealed phonon confinement effect when compared with those of ZnO bulk powder, nanoribbons, and nanoparticles. Photoluminescence exhibited strong ultraviolet emission at 3.29,eV under 355,nm excitation and green emission at 2.21,eV under 514.5,nm excitation. No catalyst particles were found at the tip of the nanowires, suggesting that the growth mechanism followed a self-catalyzed and saturated vapor,liquid,solid (VLS) model. Self-alignment of nanowires was attributed to the local balance and steady state of vapor flow at the substrate. The growth technique would be of particular interest for direct integration in the current silicon-technology-based optoelectronic devices. [source] Well-Defined Fullerene Nanowire Arrays,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2003Y.-G. Guo Abstract Fullerene nanowire arrays with well-defined size and length have been prepared by a controllable technique. Fullerene molecules such as C60 are introduced into the pores of anodic aluminum oxide (AAO) templates under a direct current (DC) electric field and polymerized in the pores. Structure analysis shows that the C60 nanowires are mainly polycrystalline, and a rhombohedral polymeric phase is observed in their vibration spectra. The electrical conductivity of so-prepared nanowire arrays show a semiconducting behavior. The ability to fabricate the fullerene nanowire arrays with controlled structures represents an important step toward the development of chemical sensors and nanoscale electronic devices based on fullerenes. [source] Formation of Thick Porous Anodic Alumina Films and Nanowire Arrays on Silicon Wafers and Glass,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2003O. Rabin Abstract A method for the fabrication of thick films of porous anodic alumina on rigid substrates is described. The anodic alumina film was generated by the anodization of an aluminum film evaporated on the substrate. The morphology of the barrier layer between the porous film and the substrate was different from that of anodic films grown on aluminum substrates. The removal of the barrier layer and the electrochemical growth of nanowires within the ordered pores were accomplished without the need to remove the anodic film from the substrate. We fabricated porous anodic alumina samples over large areas (up to 70 cm2), and deposited in them nanowire arrays of various materials. Long nanowires were obtained with lengths of at least 9 ,m and aspect ratios as high as 300. Due to their mechanical robustness and the built-in contact between the conducting substrate and the nanowires, the structures were useful for electrical transport measurements on the arrays. The method was also demonstrated on patterned and non-planar substrates, further expanding the range of applications of these porous alumina and nanowire assemblies. [source] Bottom-Imprint Method for VSS Growth of Epitaxial Silicon Nanowire Arrays with an Aluminium CatalystADVANCED MATERIALS, Issue 46 2009Zhang Zhang A bottom-imprint method to fabricate high-quality Si [100] nanowire arrays is described (see figure). This new approach combines the functions of a highly ordered anodic aluminum oxide (AAO) template that acts as both a stamp and a template. Vertically aligned, Al-catalyzed Si nanowire (NW) arrays are grown epitaxially on the Si substrate with a narrow size distribution. [source] Precisely Defined Heterogeneous Conducting Polymer Nanowire Arrays , Fabrication and Chemical Sensing ApplicationsADVANCED MATERIALS, Issue 20 2009Yixuan Chen Heterogeneous conducting polymer nanostructures are fabricated using a newly developed method. Completely isolated nanowires of several conducting polymer materials can be fabricated side-by-side with perfect registry to each other on a rigid or flexible substrate. Results of a chemical sensing study using PPY and PEDOT nanowires are presented (see figure). [source] Morphological Control of Single-Crystalline Silicon Nanowire Arrays near Room Temperature,ADVANCED MATERIALS, Issue 20 2008Chia-Yun Chen Control of the orientation, diameter, and length of silicon nanowires (SiNWs) is achieved in large-scale single-crystalline SiNW arrays fabricated by a statistical electroless metal deposition technique. Taguchi methods are employed to optimize the diameter control and to understand the influence of all processing factors on the growth. The ,100, directions are found to be the preferred crystallographic orientation of the growing SiNWs (see figure). [source] Focused-Ion-Beam-Based Selective Closing and Opening of Anodic Alumina Nanochannels for the Growth of Nanowire Arrays Comprising Multiple Elements,ADVANCED MATERIALS, Issue 13 2008Nai-Wei Liu A lithographic process based on focused ion beam bombardment is developed for selectively closing and opening nanochannels on a porous anodic alumina film. This resist-free process is based on the use of focused ion beams with different energies that strike a balance between material sputtering and material relocation. This process is used to selectively grow nanowire patterns of different elements. [source] Ultrafine Single-Crystalline Gold Nanowire Arrays by Oriented Attachment,ADVANCED MATERIALS, Issue 14 2007A. Halder Ultrafine single-crystalline gold nanowires (see figure) are synthesized by oriented attachment of nanoparticles in the solution phase. An amine capping agent is preferentially removed from the {111} planes, which causes the wires to form by fusion along these planes. Such nanowires can be used as the fundamental building blocks for nanoelectronics, and will enable basic studies on electric transport in one-dimensional structures to be carried out. [source] Synthesis of Vertical High-Density Epitaxial Si(100) Nanowire Arrays on a Si(100) Substrate Using an Anodic Aluminum Oxide Template,ADVANCED MATERIALS, Issue 7 2007T. Shimizu Growth of vertical epitaxial Si(100) nanowires on Si(100) substrates is demonstrated (see figure) using a combination of an anodic aluminum oxide template, catalytic Au particles embedded in nanopores directly on the Si substrate by using electroless deposition, and vapor,liquid,solid growth using SiH4. HF acid treatment of the porous alumina template is important to realize a direct contact between deposited Au in the AAO nanopores and the Si substrate. [source] Titelbild: Supersensitive Detection of Explosives by Silicon Nanowire Arrays (Angew. Chem.ANGEWANDTE CHEMIE, Issue 38 201038/2010) TNT und andere Explosivstoffe werden in Luft durch Anordnungen von Siliciumnanodrähten erkannt, die mit Monoschichten eines elektronenreichen Aminosilans modifiziert sind. F. Patolsky et,al. beschreiben diese Funktionseinheiten in ihrer Zuschrift auf S.,6982,ff.: Die elektronenarmen Moleküle des Explosivstoffs werden über einen Ladungstransfer an die Monoschicht gebunden, was einen schnellen und markierungsfreien Nachweis der Explosivstoffe bis hinab zu 0.1-femtomolarer Konzentration (1×10,6,ppt) ermöglicht. Bildgestaltung durch Tremani. [source] Supersensitive Detection of Explosives by Silicon Nanowire Arrays,ANGEWANDTE CHEMIE, Issue 38 2010Yoni Engel Chip als Spürnase: Empfindlicher denn je lassen sich Explosivstoffe mit Siliciumnanodraht-Feldeffekttransistor-Sensoranordnungen nachweisen, die mit Monoschichten eines elektronenreichen Aminosilans modifiziert sind und Komplexe mit den Analyten bilden (siehe Bild). Diese Nano-,Spürnasen" bemerken TNT-Konzentrationen von nur 1×10,6,ppt und sind somit Spürhunden und allen anderen bekannten Nachweismethoden für Explosivstoffe überlegen. [source] Synthesis and Photoelectrochemical Study of Vertically Aligned Silicon Nanowire Arrays,ANGEWANDTE CHEMIE, Issue 51 2009Guangbi Yuan Photoelektroden aus Drähtchen: Parallele Siliciumnanodrähte wurden chemisch synthetisiert und auf die Umwandlung von Sonnenenergie hin geprüft. Experimente belegen, dass solche Nanodrahtanordnungen durch langsames Wachstum aufgebaut werden können. In photoelektrochemischen Untersuchungen erwiesen sich die Nanodrähte als vielversprechende Kandidaten für effiziente Solarzellen. [source] Tantalum-Doped Titanium Dioxide Nanowire Arrays for Dye-Sensitized Solar Cells with High Open-Circuit Voltage,ANGEWANDTE CHEMIE, Issue 43 2009Xinjian Feng Dr. Nanodrähte in der Sonne: Durch Hydrothermalsynthese wurden homogen tantaldotierte Titanoxid-Nanodrahtanordnungen auf transparenten leitfähigen Oxidsubstraten hergestellt. Mit dieser Methode sollten Titanoxid-Nanodrähte mit unterschiedlichen Übergangsmetallen dotiert werden können. So hergestellte Funktionseinheiten sind leistungsstärker, wie farbstoffsensibilisierte Solarzellen mit sehr hoher Photo-Ruhespannung belegen (siehe Bild). [source] Heterointegration of Pt/Si/Ag Nanowire Photodiodes and Their Photocatalytic PropertiesADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Yongquan Qu Abstract Photocatalyst mediated photoelectrochemical processes can make use of the photogenerated electrons and holes onsite for photocatalytic redox reactions, and enable the harness and conversion of solar energy into chemical energy, in analogy to natural photosynthesis. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here, it is shown that a Pt/Si/Ag nanowire heterostructure can be rationally synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. The synthesis of Pt/Si/Ag nanowire diodes involves a scalable process including the formation of silicon nanowire array through wet chemical etching, electrodeposition of platinum and photoreduction of silver. The Pt/Si/Ag diodes exhibit highly efficient photocatalytic activity for a wide range of applications including environmental remediation and solar fuel production in the visible range. In this article, photodegradation of indigo carmine and 4-nitrophenol are used to evaluate the photoactivity of Pt/Si/Ag diodes. The Pt/Si/Ag diodes also show high activity for photoconversion of formic acid into carbon dioxide and hydrogen. [source] Heterointegration of Pt/Si/Ag Nanowire Photodiodes and Their Photocatalytic PropertiesADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Yongquan Qu Abstract Photocatalyst mediated photoelectrochemical processes can make use of the photogenerated electrons and holes onsite for photocatalytic redox reactions, and enable the harness and conversion of solar energy into chemical energy, in analogy to natural photosynthesis. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here, it is shown that a Pt/Si/Ag nanowire heterostructure can be rationally synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. The synthesis of Pt/Si/Ag nanowire diodes involves a scalable process including the formation of silicon nanowire array through wet chemical etching, electrodeposition of platinum and photoreduction of silver. The Pt/Si/Ag diodes exhibit highly efficient photocatalytic activity for a wide range of applications including environmental remediation and solar fuel production in the visible range. In this article, photodegradation of indigo carmine and 4-nitrophenol are used to evaluate the photoactivity of Pt/Si/Ag diodes. The Pt/Si/Ag diodes also show high activity for photoconversion of formic acid into carbon dioxide and hydrogen. [source] Vertically Aligned Nanowires on Flexible Silicone using a Supported Alumina Template prepared by Pulsed AnodizationADVANCED MATERIALS, Issue 40 2009Stefan Mįtéfi-Tempfli Carpets of vertically aligned nanowires on flexible substrates are successfully realized by a template method. Applying special pulsed anodization conditions, defect-free nanoporous alumina structures supported on polydimethylsiloxane (PDMS), a flexible silicone elastomer, are created. By using this template with nanopores ending on a conducting underlayer, a high-density nanowire array can be simply grown by direct DC-electrodeposition on the top of the silicone rubber. [source] Nanowire-Templated Lateral Epitaxial Growth of Low-Dislocation Density Nonpolar a -Plane GaN on r -Plane SapphireADVANCED MATERIALS, Issue 23 2009Qiming Li Coalescence of a vertically aligned GaN nanowire array on r -plane sapphire, a technique called nanowire-templated lateral epitaxial growth, is used to grow low-dislocation density a -plane GaN. The resulting film is connected to the lattice-mismatched substrate by nanowires, which facilitates dramatic strain relaxation and leads to a significant reduction in defects. [source] Vertically Aligned Antimony Nanowires as Solid-State pH SensorsCHEMPHYSCHEM, Issue 1 2007Pai-Chun Chang Antimony pH nanoelectrodes based on Sb nanowire arrays are fabricated by a template-assisted electrodeposition technique (see picture). Based on their highly linear response to hydrogen ion (H+) concentration, the Sb nanowire array demonstrates excellent characteristics for pH detection and offers the possibility of use in nanoscale solid-state sensing devices for biological systems. [source] Perfectly Ordered, Free-Standing Nanowire Arrays With Controllable Geometry,ADVANCED ENGINEERING MATERIALS, Issue 11 2009Adam Philip Robinson We demonstrate a novel focused ion beam (FIB) based technique for the production of substrate-supported, free-standing, perfectly ordered nanowire arrays with control over the pore geometry, pitch, diameter, and length. A FIB may be used to influence the site of pore formation in ultra-thin (<1 µm) oxide nanoporous templates adhered to substrates. Electrodeposition through the template results in the production of nanowire arrays with controlled, perfect ordering. [source] A General Approach for Fabricating Arc-Shaped Composite Nanowire Arrays by Pulsed Laser DepositionADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Yue Shen Abstract Here, a new method is demonstrated that uses sideways pulsed laser deposition to deliberately bend nanowires into a desired shape after growth and fabricate arc-shaped composite nanowire arrays of a wide range of nanomaterials. The starting nanowires can be ZnO, but the materials to be deposited can be metallic, semiconductor, or ceramic depending on the application. This method provides a general approach for rational fabrication of a wide range of side-by-side or "core,shell" nanowire arrays with controllable degree of bending and internal strain. Considering the ZnO is a piezoelectric and semiconductive material, its electrical properties change when deformed. This technique has potential applications in tunable electronics, optoelectronics, and piezotronics. [source] Large-Area Silver-Coated Silicon Nanowire Arrays for Molecular Sensing Using Surface-Enhanced Raman Spectroscopy,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2008Baohua Zhang Abstract A new and facile method to prepare large-area silver-coated silicon nanowire arrays for surface-enhanced Raman spectroscopy (SERS)-based sensing is introduced. High-quality silicon nanowire arrays are prepared by a chemical etching method and used as a template for the generation of SERS-active silver-coated silicon nanowire arrays. The morphologies of the silicon nanowire arrays and the type of silver-plating solution are two key factors determining the magnitude of SERS signal enhancement and the sensitivity of detection; they are investigated in detail for the purpose of optimization. The optimized silver-coated silicon nanowire arrays exhibit great potential for ultrasensitive molecular sensing in terms of high SERS signal enhancement ability, good stability, and reproducibility. Their further applications in rapidly detecting molecules relating to human health and safety are discussed. A 10 s data acquisition time is capable of achieving a limit of detection of approximately 4,×,10,6M calcium dipicolinate (CaDPA), a biomarker for anthrax. This value is 1/15 the infectious dose of spores (6,×,10,5,M required), revealing that the optimized silver-coated silicon nanowire arrays as SERS-based ultrasensitive sensors are extremely suitable for detecting Bacillus anthracis spores. [source] Synthesis and Lasing Properties of Highly Ordered CdS Nanowire Arrays,ADVANCED FUNCTIONAL MATERIALS, Issue 9 2007L. Cao Abstract Highly ordered large-area arrays of wurtzite CdS nanowires are synthesized on Cd-foil substrates via a simple liquid reaction route using thiosemicarbazide and Cd foil as the starting materials. The CdS nanowires are single crystals growing along the [001],direction and are perpendicular to the surface of the substrate. The characteristic Raman peaks of CdS are red-shifted and show asymmetric broadening, which is ascribed to phonon confinement effects arising from the nanoscale dimensions of the nanowires. Significantly, the uniform CdS nanowire arrays can act as laser cavities in the visible-light range, leading to bandgap lasing at ca.,515,nm with obvious modes. The high density of nuclei and the preferential growth direction induce the formation of aligned CdS nanowires on the metal substrate. [source] Bottom-Imprint Method for VSS Growth of Epitaxial Silicon Nanowire Arrays with an Aluminium CatalystADVANCED MATERIALS, Issue 46 2009Zhang Zhang A bottom-imprint method to fabricate high-quality Si [100] nanowire arrays is described (see figure). This new approach combines the functions of a highly ordered anodic aluminum oxide (AAO) template that acts as both a stamp and a template. Vertically aligned, Al-catalyzed Si nanowire (NW) arrays are grown epitaxially on the Si substrate with a narrow size distribution. [source] | ||||||||||||||||