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Zinc Oxide (zinc + oxide)
Terms modified by Zinc Oxide Selected AbstractsElectrocatalysis and Amperometric Detection of the Reduced Form of Nicotinamide Adenine Dinucleotide at Toluidine Blue/Zinc Oxide Coated ElectrodesELECTROANALYSIS, Issue 18 2007Ashok Kumar Abstract Thin toluidine blue (TBO) and zinc oxide (ZnO) hybrid films have been grown on glassy carbon electrode (GCE) and indium tin oxide coated (SnO2) glass electrodes by using cyclic voltammetry (CV). Scanning electron microscopy (SEM) images revealed spherical and beads-like shape of highly oriented TBO/ZnO hybrid films. Energy dispersive spectrometry (EDS) results declared that the films composed mainly of Zn and O. Moreover, TBO/ZnO hybrid films modified electrode is electrochemically active, dye molecules were not easily leached out from the ZnO matrix and the hybrid films can be considered for potential applications as sensor for amperometric determination of reduced nicotinamide adenine dinucleotide (NADH) at 0.0,V. A linear correlation between electrocatalytic current and NADH concentration was found to be in the range between 25,,M and 100,,M in phosphate buffer. In addition, we observed that dopamine, ascorbic acid and uric acid are not interference in amperometric detection of NADH in this proposed method. In addition, TBO/ZnO hybrid film modified electrode was highly stable and its response to the NADH also remained relentless. [source] Solution-Deposited Zinc Oxide and Zinc Oxide/Pentacene Bilayer Transistors: High Mobility n-Channel, Ambipolar, and Nonvolatile Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 12 2008Bhola Nath Pal Abstract A solution processed n-channel zinc oxide (ZnO) field effect transistor (FET) was fabricated by simple dip coating and subsequent heat treatment of a zinc acetate film. The field effect mobility of electrons depends on ZnO grain size, controlled by changing the number of coatings and zinc acetate solution concentration. The highest electron mobility achieved by this method is 7.2,cm2 V,1 s,1 with On/Off ratio of 70. This electron mobility is higher than for the most recently reported solution processed ZnO transistor. We also fabricated bilayer transistors where the first layer is ZnO, and the second layer is pentacene, a p-channel organic which is deposited by thermal evaporation. By changing the ZnO grain size (or thickness) this type of bilayer transistor shows p-channel, ambipolar and n-channel behavior. For the ambipolar transistor, well balanced electron and hole mobilities are 7.6,×,10,3 and 6.3,×,10,3,cm2 V,1 s,1 respectively. When the ZnO layer is very thin, the transistor shows p-channel behavior with very high reversible hysteresis. The nonvolatile tuning function of this transistor was investigated. [source] Structure,Property,Function Relationships in Nanoscale Oxide Sensors: A Case Study Based on Zinc Oxide,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2007S. Polarz Abstract Chemical sensing on oxide sensors is a complex phenomenon involving catalytic activity as well as electronic properties. Thus, the properties of oxide sensors are highly sensitive towards structural changes. Effects like surface area, grain size, and, in addition, the occurrence of defects give separate contributions to the current. Structure,property,function relationships can be elucidated using a combination of state-of-the-art analytical techniques. It is shown, that impurity atoms in the oxide lattice influence the performance of ZnO sensors more strongly than the other factors. [source] Ultralow-Threshold Laser Realized in Zinc OxideADVANCED MATERIALS, Issue 16 2009Hai Zhu Lasing action is realized in a ZnO/GaN heterojunction by employing a MgO interlayer. The MgO layer can confine electrons in the ZnO layer, while holes can pass through the MgO layer and enter into the n-ZnO layer from the p-GaN layer. The threshold of the lasing action is as low as 0.8,mA.. [source] Evidence for the Microwave Effect During the Annealing of Zinc OxideJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2007J. Binner A microwave/conventional hybrid furnace has been used to anneal virtually fully dense zinc oxide ceramics under pure conventional and a microwave/conventional hybrid heating regime with a view to obtaining evidence for the "microwave effect" during the resulting grain growth. In each case it was ensured that each sample within a series had an identical thermal history in terms of its temperature/time profile. The results showed that grain growth was enhanced during hybrid heating compared with pure conventional heating; the greatest enhancement, a factor of ,3 increase in average grain size, was observed in the range 1100°,1150°C. The grain growth exponent decreased from 3 during conventional heating to 1.4 during hybrid heating in this temperature range, suggesting an acceleration of the diffusional processes involved. Temperature gradients within the samples were found to be too small to explain the results. This suggests that clear evidence has been found to support the existence of a genuine "microwave effect." [source] ChemInform Abstract: Zinc Oxide,Tetrabutylammonium Bromide Tandem as a Highly Efficient, Green, and Reusable Catalyst for the Michael Addition of Pyrimidine and Purine Nucleobases to ,,,-Unsaturated Esters under Solvent-Free Conditions.CHEMINFORM, Issue 39 2008Abdolkarim Zare Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Ring-Fluorinated Fluoresceins as an Organic Photosensitizer for Dye-Sensitized Solar Cells Using Nanocrystalline Zinc Oxide.CHEMINFORM, Issue 26 2006Kazumasa Funabiki Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Solvent-Free and One-Step Beckmann Rearrangement of Ketones and Aldehydes by Zinc Oxide.CHEMINFORM, Issue 39 2002Hashem Sharghi Abstract For Abstract see ChemInform Abstract in Full Text. [source] Low temperature hydrothermal growth and optical properties of ZnO nanorodsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2009J. H. Yang Abstract Well-faceted hexagonal ZnO nanorods have been synthesized by a simple hydrothermal method at relative low temperature (90°C) without any catalysts or templates. Zinc oxide (ZnO) nanorods were grown in an aqueous solution that contained Zinc chloride (ZnCl2, Aldrich, purity 98%) and ammonia (25%). Most of the ZnO nanorods show the perfect hexagonal cross section and well-faceted top and side surfaces. The diameter of ZnO nanorods decreased with the reaction time prolonging. The samples have been characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) measurement. XRD pattern confirmed that the as-prepared ZnO was the single-phase wurtzite structure formation. SEM results showed that the samples were rod textures. The surface-related optical properties have been investigated by photoluminescence (PL) spectrum and Raman spectrum. Photoluminescence measurements showed each spectrum consists of a weak band ultraviolet (UV) band and a relatively broad visible light emission peak for the samples grown at different time. It has been found that the green emission in Raman measurement may be related to surface states. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Solvent-Free Microwave-Assisted Efficient Synthesis of 4,4-Disubstituted 2-OxazolinesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2003Fernando García-Tellado Abstract 4,4-Disubstituted 2-oxazolines have been synthesized by a microwave-promoted solvent-free direct condensation of carboxylic acids and disubstituted ,-amino alcohols in good to excellent yields. Zinc oxide is a very good solid support in cases where a Lewis acid is required. The method described herein is a very good, safe, clean, economical, and environmentally friendly alternative to the classical procedures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Microstructure, Morphology, and Ultraviolet Emission of Zinc Oxide Nanopolycrystalline Films by the Modified Successive Ionic Layer Adsorption and Reaction MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2010Daoli Zhang Zinc oxide (ZnO) nanopolycrystalline films were successfully prepared by the modified successive ionic layer adsorption and reaction technique, which was based on the alternate immersion of substrate in the alkaline zinc precursor and deionized water. ZnO films were formed through an accumulation of ZnO crystal clusters. The size of the clusters ranged from 200 to 500 nm based on scanning electron micrographic images. Prepared ZnO films exhibited a wurtzite structure, with good microstructure, surface morphology, and optical properties. Ethanolamine was used as a complex reagent, which improved the adsorption of zinc complex with the substrate. Effects of processing parameters on the properties of ZnO nanopolycrystalline films were studied in detail. Intensive and sharp ultraviolet emission peaks at about 400 nm could be observed in the photoluminescence spectra. [source] Effects of Individual Layer Thickness on the Microstructure and Optoelectronic Properties of Sol,Gel-Derived Zinc Oxide Thin FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2008Noureddine Bel Hadj Tahar Zinc oxide (ZnO) thin films were prepared under different conditions on glass substrates using a sol,gel process. The microstructure of ZnO films was investigated by means of diffraction analysis, and plan-view and cross-sectional scanning electron microscopy. It was found that the preparation conditions strongly affected the structure and the optoelectronic properties of the films. A structural evolution in morphology from spherical to columnar growth was observed. The crystallinity of the films was improved and columnar film growth became more dominant as the zinc concentration and the substrate withdrawal speed decreased. The individual layer thickness for layer-by-layer homoepitaxy growth that resulted in columnar grains was <20 nm. The grain columns are grown through the entire film with a nearly unchanged lateral dimension through the full film thickness. The columnar ZnO grains are c -axis oriented perpendicular to the interface and possess a polycrystalline structure. Optical transmittance up to 90% in the visible range and electrical resistivity as low as 6.8 × 10,3·,·cm were obtained under optimal deposition conditions. [source] Synthesis of Zinc Oxide Nanostructures with Controlled Morphologies Using a Simple Sonochemical MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2007Xi-peng Pu Zinc oxide (ZnO) nanostructures were synthesized by a simple sonochemical method without the assistance of an additional surfactant. The morphologies can simply be controlled only by changing the addition sequence of NH3·H2O. When NH3·H2O was added before or at the beginning of the ultrasonic treatment, a flower-like nanostructure and ellipsoidal particles self-assembled by nanorods were obtained, respectively. The strong visible emission implied high atomic defects. The emission intensity was dependent on the addition sequence of NH3·H2O greatly. [source] Microstructure of Varistors Prepared with Zinc Oxide Nanoparticles Coated with Bi2O3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2004Fangli Yuan Zinc oxide (ZnO) nanoparticles coated with 1,5 wt% Bi2O3 were prepared by precipitating a Bi(NO3)3 solution onto a ZnO precursor. Transmission electron microscopy showed that a homogeneous Bi2O3 layer coated the surface of the ZnO nanoparticles and that the ZnO particle size was ,30,50 nm. Scanning electron microscopy showed that ZnO grains sintered at 1150°C were homogeneous in size and surrounded by a uniform Bi2O3 layer. When the ZnO grains were surrounded fully by Bi2O3 liquid phases, further increases in the ZnO grain size were not affected by the Bi2O3 content. This predesigned ZnO nanoparticle structure was shown to promote homogeneous ZnO grains with perfect crystal growth. [source] Bioinspired Mineralization of Inorganics from Aqueous Media Controlled by Synthetic PolymersMACROMOLECULAR BIOSCIENCE, Issue 2 2007Katarzyna Gorna Abstract The formation of inorganic structures in nature is commonly controlled by biogenic macromolecules. The understanding of mineralization phenomena and the nucleation and growth mechanisms involved is still a challenge in science but also of great industrial interest. This article focuses on the formation and mineralization of two archetypical inorganic materials: zinc oxide and amorphous calcium carbonate (ACC). Zinc oxide is selected as a model compound to investigate the role that polymers play in mineralization. Most of the effort has been devoted to the investigation of the effects of double-hydrophilic block and graft copolymers. Recent work has demonstrated that latex particles synthesized by miniemulsion polymerization, properly functionalized by various chemical groups, have similar effects to conventional block copolymers and are excellently suited for morphology control of ZnO crystals. Latex particles might serve as analogues of natural proteins in biomineralization. The second example presented, ACC, addresses the issue of whether this amorphous phase is an intermediate in the biomineralization of calcite, vaterite, or aragonite. Conditions under which amorphous calcium carbonate can be obtained as nanometer-sized spheres as a consequence of a liquid,liquid phase segregation are presented. Addition of specific block copolymers allows control of the particle size from the micrometer to the submicrometer length scale. The physical properties of novel materials synthesized from concentrated solution and their potential applications as a filler of polymers are also discussed. [source] Effect of precursor concentration on the structural and optical properties of ZnO nanostructuresPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2010Sharul Ashikin Kamaruddin Abstract Zinc oxide (ZnO) is an emerging material in large area electronic applications such as thin-film solar cells and transistors. We report on the fabrication and characterization of ZnO nanostructures. ZnO nanostructures have been synthesized using sol,gel immerse technique on oxidized silicon substrates. Different precursor's concentrations ranging from 0.0001 to 0.01,M using zinc nitrate hexahydrate [Zn(NO3)2.6H2O] and hexamethylenetetramine [C6H12N4] has been employed in the synthesis of ZnO nanostructures. The surface morphologies were examined using scanning electron microscope (SEM) and atomic force microscopy (AFM). In order to investigate the structural properties, the ZnO nanostructures were measured using X-ray diffractometer (XRD). The optical properties of the ZnO nanostructures were measured using photoluminescence (PL) spectrometer. [source] Review Article: ZnO: From basics towards applicationsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 9 2007C. Klingshirn The cover picture of the current issue depicts a selection of luminescence colours of zinc oxide and relates to the Review Article by Claus Klingshirn (University of Karlsruhe) [1]. Zinc oxide is a wide band gap semiconductor which shows intrinsic luminescence in the blue and near-UV spectral range as well as extrinsic emission from the blue to the infrared. The author discusses in detail why ZnO is a promising material for optoelectronics, in particular for the blue and ultraviolet region of the spectrum. His fields of research include the (non)linear, temporally or spatially resolved spectroscopy of semiconductors and their growth by molecular beam epitaxy. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preface: phys. stat. sol. (c) 1/10PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2004Eun-Kyung Suh The Fifth International Symposium on Blue Laser and Light Emitting Diodes (ISBLLED-2004) was held in Gyeongju, Korea from 15,19 March 2004. Gyeongju, the ancient capital of the thousand-year Silla kingdom (57 B.C. to 935 A.D.) provided additional pleasure to the participants as an exceptional open-air museum with antique treasures scattered all around the city. During the last decade we have witnessed remarkable developments in wide-gap semiconductors and light emitting devices in the spectral range from the visible to deep UV. The purpose of the Symposium was to provide a forum for intensive discussion on the issues and main progress especially in optoelectronic devices, material growth and characterization, and quantum structures of wide bandgap semiconductors. A total of 243 papers including 220 contributed and 23 invited ones were presented and discussed by 487 participants from 17 countries world-wide. Among them, 154 manuscripts were submitted and reviewed by the usual evaluation process of physica status solidi. Some were rejected or withdrawn, and finally 139 papers are published in the special issues of physica status solidi (a), (b), and (c). We gratefully acknowledge the referees for their careful review. The papers are grouped into 7 categories. The subheadings and the number of papers in each are as follows: Optoelectronic devices, 43; Growth and characterization, 45; Nano and quantum structures, 21; Contacts, 8; Zinc oxide, 9; Indium nitride and indium rich InGaN, 6; Others, 7. The special session of the Symposium, "The LED Highlight", designed partially to meet the challenging targets of the technology, i.e., energy savings and clean environment preservation, drew much attention and is edited as a special coloured section in this issue. The next symposium is scheduled for Montpellier, France, in 2006. We wish the organizers of that symposium the best of luck and hope to see all of the ISBLLED-2004 participants again at ISBLLED-2006. ISBLLED-2004 was sponsored by The Research Society for the Wide-gap Semiconductors, Korean Physical Society, Office of Naval Research, Korea Science and Engineering Foundation, Korea Research Foundation, Korea Association for Photonics Industry Development, Asian Office of Aerospace Research and Development, and Korea Photonics Technology Institute. We would like to thank Ms. E. S. Hwang for her devotion to the preparation and the Proceedings of the symposium including the manuscript handling for publication. [source] Transformation of a zinc inclusion complex to wurtzite ZnS microflowers under solvothermal conditionsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2010Liwei Mi Abstract Wurtzite zinc sulfide (ZnS) microflowers were synthesized successfully by a convenient solvothermal route in ethylene glycol (EG) and ethylenediamine (EN) using thiourea and zinc inclusion complex as starting materials. The inclusion complex {[Zn(bipy)2(H2O)2](4-Cl-3-NH2 -C6H3SO3)2(bipy) (H2O)2}n was achieved by the reaction of zinc oxide (ZnO) and 4-Cl-3-NH2 -C6H3SO3 with the bridging ligand bipy under moderate conditions, in which bipy is 4,4,-bipyridine and 4-Cl-3-NH2C6H3SO3NH is 4-Chloro-3-aminobenzene sulfonic acid. The phase purity of bulk products was confirmed by powder X-ray diffraction and element analysis. The factors that might affect the purity of the ZnS product during the synthesis were discussed in detail. It was found that the products were significantly affected by the mixed solvents and the starting materials. X-ray single crystal diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) were used to characterize the products. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation of undoped and indium doped ZnO thin films by pulsed laser deposition methodCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2005B. Kotlyarchuk Abstract An original modification of the standard Pulse Laser Deposition (PLD) method for preparing both undoped and indium doped zinc oxide (ZnO:In) thin films at low substrate temperature is proposed. This preparation method does not demand any further post-deposition annealing treatment of the grown films. The developed method allows to grow thin films at low substrate temperature that prevents them from the considerable loss of their intrinsic electrical and optical properties. The influence of deposition parameters on the electrical and optical parameters of the undoped and the indium doped ZnO thin films is also analysed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Vertical-type organic device using thin-film ZnO transparent electrodeELECTRICAL ENGINEERING IN JAPAN, Issue 2 2007Hiroyuki Iechi Abstract We propose a double heterojunction organic light-emitting diode (OLED) using a zinc oxide (ZnO) film, which works as a transparent and electron injection layer. The crystal structure of the ZnO films as a function of Ar/O2 flow ratio and the basic characteristics of the OLED depending on the ZnO sputtering conditions are investigated. Excellent characteristics of the novel OLED were obtained, as high as 470 cd/m2 at 22 V and 7.6 mA/cm2. The results obtained here demonstrate that the vertical organic light-emitting transistor (OLET) using a ZnO layer as an electron injection layer is promising as a key element for flexible sheet displays. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 49,55, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20151 [source] Zinc Oxide/Zinc Hexacyanoferrate Hybrid Film-Modified Electrodes for Guanine DetectionELECTROANALYSIS, Issue 18 2007Hung-Wei Chu Abstract An electroactive polynuclear hybrid films of zinc oxide and zinc hexacyanoferrate (ZnO/ZnHCF) have been deposited on electrode surfaces from H2SO4 solution containing Zn(NO3)2 and K3[Fe(CN)6] by repetitive potential cycling method. Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) measurements demonstrate the steady growth of hybrid film. There are two redox couples present in the voltammograms of hybrid film and it is obvious in the case of pH,2. Surface morphology of hybrid film was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Energy dispersive spectrometer (EDS) data confirm existence of zinc oxide in the hybrid film. The effect of type of monovalent cations on the redox behavior of resulting film was investigated. In pure supporting electrolyte, electrochemical responses of modified electrode resemble with that of a surface immobilized redox couple. The electrocatalytic activity of ZnO/ZnHCF hybrid film was investigated towards guanine using cyclic voltammetry and rotating disc electrode (RDE) techniques. Finally, feasibility of using ZnO/ZnHCF hybrid film-coated electrodes for guanine estimation in flow injection analysis (FIA) was also investigated. [source] Electrocatalysis and Amperometric Detection of the Reduced Form of Nicotinamide Adenine Dinucleotide at Toluidine Blue/Zinc Oxide Coated ElectrodesELECTROANALYSIS, Issue 18 2007Ashok Kumar Abstract Thin toluidine blue (TBO) and zinc oxide (ZnO) hybrid films have been grown on glassy carbon electrode (GCE) and indium tin oxide coated (SnO2) glass electrodes by using cyclic voltammetry (CV). Scanning electron microscopy (SEM) images revealed spherical and beads-like shape of highly oriented TBO/ZnO hybrid films. Energy dispersive spectrometry (EDS) results declared that the films composed mainly of Zn and O. Moreover, TBO/ZnO hybrid films modified electrode is electrochemically active, dye molecules were not easily leached out from the ZnO matrix and the hybrid films can be considered for potential applications as sensor for amperometric determination of reduced nicotinamide adenine dinucleotide (NADH) at 0.0,V. A linear correlation between electrocatalytic current and NADH concentration was found to be in the range between 25,,M and 100,,M in phosphate buffer. In addition, we observed that dopamine, ascorbic acid and uric acid are not interference in amperometric detection of NADH in this proposed method. In addition, TBO/ZnO hybrid film modified electrode was highly stable and its response to the NADH also remained relentless. [source] Fabrication and evaluation of complementary logic circuits using zinc oxide and pentacene thin film transistorELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 9 2009Hiroyuki Iechi Abstract We fabricated hybrid complementary inverters with n-channel zinc oxide (ZnO) transistors as the n-type inorganic material and p-channel organic transistors using pentacene as the p-type organic material. The complementary inverter exhibited a large voltage gain of 10 to 12 and a cutoff frequency of 0.5 kHz. ZnO thin film transistors show n-type semiconducting properties having field-effect mobility of 2.1×10,3 cm2/Vs. On the other hand, pentacene thin film transistors show p-type semiconducting properties having field-effect mobility of 3.2×10,2 cm2/Vs. We describe basic charge transfer characteristics of ZnO thin films. The results obtained here demonstrate that it is important for the transistor using ZnO to be injected charge from electrode to semiconducting material effectively. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(9): 36,42, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10085 [source] A Study of the Influence of Composition on the Microstructural Properties of ZnO/Al2O3 Mixed Oxides,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2009Shaojun Miao Abstract A series of ZnO/Al2O3 mixed oxide samples with varyingZn/Al ratio is prepared by coprecipitation, ageing, drying, and calcination. Samples are investigated in the state after drying and calcination. The applied methods include X-ray diffraction, solid-state 27Al magic-angle spinning nuclear magnetic resonance spectroscopy, transmission electron microscopy and thermogravimetric experiments coupled with evolved gas analysis. Phases present in the dried precursor samples include hydrozincite, zaccagnaite, and an unknown phase. After calcination zinc oxide and spinel can be found. All results indicate the substitution of Al ions for Zn ions in zinc oxide of zinc-rich samples. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] X-Ray absorption fine structure analysis of the local environment of zinc in dentine treated with zinc compoundsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2005Tsutomu Takatsuka It has been reported that zinc oxide (ZnO) inhibits dentine demineralization. By using the X-ray absorption fine structure (XAFS) technique, our aims in this study were to provide information about the local environment of zinc atoms in dentine that had been treated with zinc compounds. We measured the Zn K-edge X-ray absorption near-edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS) of dentine specimens treated with zinc chloride or ZnO. In XAFS analyses, the spectra of dentine specimens treated with ZnO (D-ZO) or with zinc chloride (D-ZC) were similar and obviously different from the reference ZnO spectrum. This suggests that most of the zinc atoms detected in D-ZO are not derived from particles of ZnO. The spectra of D-ZO and D-ZC were similar to the spectrum of the synthetic, zinc-containing hydroxyapatite, but were not similar to that of zinc in ZnCl2 -treated collagen. The results of this study suggest that most of the zinc atoms detected were attached to hydroxyapatite and not to collagen. [source] Electro-Optical Materials: Electrically Addressable Hybrid Architectures of Zinc Oxide Nanowires Grown on Aligned Carbon Nanotubes (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Mater. Hybrid assemblies of zinc oxide (ZnO) nanowires grown on carbon nanotubes (CNTs) are presented by A. J. Hart et al. on page 2470. The foreground shows a transmission electron micrograph of an individual hybrid bundle where the ZnO nanowires extend radially from the surface of the CNTs. The background shows a scanning electron micrograph of the sidewall of a ZnO/CNT hybrid forest. Color was added using Adobe Photoshop. [source] Optically-Pumped Lasing in Hybrid Organic,Inorganic Light-Emitting DiodesADVANCED FUNCTIONAL MATERIALS, Issue 13 2009Myoung Hoon Song Abstract Here, the use of metal oxide layers both for charge transport and injection into an emissive semiconducting polymer and also for the control of the in-plane waveguided optical modes in light-emitting diodes (LEDs) is reported. The high refractive index of zinc oxide is used to confine these modes away from the absorbing electrodes, and include a nano-imprinted grating in the polymer layer to introduce distributed feedback and enhance optical out-coupling. These structures show a large increase in the luminescence efficiency over conventional devices, with photoluminescence efficiency increased by up to 45%. Furthermore, optically-pumped lasing in hybrid oxide polymer LEDs is demonstrated. A tuneable lasing emission is also obtained in a single device structure by employing a graduated thickness of a zinc oxide inter-layer. This demonstrates the scope for using such architectures to improve the external efficiency of organic semiconductor LEDs, and opens new possibilities for the realization of polymer injection lasers. [source] Size Effect on Properties of Varistors Made From Zinc Oxide Nanoparticles Through Low Temperature Spark Plasma SinteringADVANCED FUNCTIONAL MATERIALS, Issue 11 2009Léna Saint Macary Abstract Conditions for the elaboration of nanostructured varistors by spark plasma sintering (SPS) are investigated, using 8-nm zinc oxide nanoparticles synthesized following an organometallic approach. A binary system constituted of zinc oxide and bismuth oxide nanoparticles is used for this purpose. It is synthesized at room temperature in an organic solution through the hydrolysis of dicyclohexylzinc and bismuth acetate precursors. Sintering of this material is performed by SPS at various temperatures and dwell times. The determination of the microstructure and the chemical composition of the as-prepared ceramics are based on scanning electron microscopy and X-ray diffraction analysis. The nonlinear electrical characteristics are evidenced by current,voltage measurements. The breakdown voltage of these nanostructured varistors strongly depends on grain sizes. The results show that nanostructured varistors are obtained by SPS at sintering temperatures ranging from 550 to 600,°C. [source] Solution-Deposited Zinc Oxide and Zinc Oxide/Pentacene Bilayer Transistors: High Mobility n-Channel, Ambipolar, and Nonvolatile Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 12 2008Bhola Nath Pal Abstract A solution processed n-channel zinc oxide (ZnO) field effect transistor (FET) was fabricated by simple dip coating and subsequent heat treatment of a zinc acetate film. The field effect mobility of electrons depends on ZnO grain size, controlled by changing the number of coatings and zinc acetate solution concentration. The highest electron mobility achieved by this method is 7.2,cm2 V,1 s,1 with On/Off ratio of 70. This electron mobility is higher than for the most recently reported solution processed ZnO transistor. We also fabricated bilayer transistors where the first layer is ZnO, and the second layer is pentacene, a p-channel organic which is deposited by thermal evaporation. By changing the ZnO grain size (or thickness) this type of bilayer transistor shows p-channel, ambipolar and n-channel behavior. For the ambipolar transistor, well balanced electron and hole mobilities are 7.6,×,10,3 and 6.3,×,10,3,cm2 V,1 s,1 respectively. When the ZnO layer is very thin, the transistor shows p-channel behavior with very high reversible hysteresis. The nonvolatile tuning function of this transistor was investigated. [source] | |||||||||||||||||||||||||||||||||||||