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Micro & Nano Letters, IET

Issue 12 • Date December 2011

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Displaying Results 1 - 13 of 13
  • Thermoluminescence and mechanoluminescence of gamma-ray-irradiated SrB4O7:Dy phosphors

    Page(s): 978 - 981
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (183 KB)  

    Undoped and Dy-doped SrB4O7 phosphors were synthesised by solid-state reaction technique. X-ray diffraction pattern of the sample was recorded to confirm the formation of the sample. Thermoluminescence (TL) and mechanoluminescence (ML) of the gamma-ray-irradiated samples have been studied. A band in the range 200-260-C was observed in the TL glow curve of the gamma-ray-irradiated phosphors. Occurrence of a band in the TL glow curve is probably due to the overlapping of two or more than two quasi-static TL peaks. ML was excited impulsively by dropping a piston of mass 0.6-kg onto the samples with various impact velocities. A single peak was observed in the ML intensity against time curve. ML peak intensity increases with increasing impact velocity (stress rate). To study the effect of deformation on the TL of the SrB4O7 phosphors, TL of the deformed samples was recorded. It was observed that TL intensity reduced drastically and it was also observed that TL intensity decreased with increasing the deformation rate and the shape of glow curve was also changed. Decrement in TL with deformation is probably due to the de-trapping of trapped charge carriers responsible for TL and de-trapping of charge carriers increases with increasing deformation rate. Post-irradiation deformation may cause the redistribution of traps; consequently, shape of the glow curve may change. View full abstract»

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  • Facile synthesis of MnO2/ordered mesoporous carbon composite for supercapacitors

    Page(s): 982 - 984
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (166 KB)  

    A technique named as incipient wetness impregnation-hydrothermal method, combining both incipient wetness impregnation and hydrothermal method is proposed to prepare MnO2/ordered mesoporous carbon (OMC) composite as high performance electrode material for supercapacitors. The composite delivers the specific capacitance of 157.6 F/g, which is larger than that of the OMC. View full abstract»

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  • Fabrication and characterisation of multipod ZnO nanostructures by CVD on Al2O3-coat Si (111) substrate

    Page(s): 985 - 987
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (226 KB)  

    Multipod ZnO nanostructures were fabricated on Al2O3-coat Si (111) substrate by chemical vapour deposition method at 1050°C using the mixture of ZnO and C powders as source materials. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy were used to synthesise the structure, morphology and microstructure of the multipod ZnO nanostructures. X-ray photoelectron spectroscopy was used to investigate the chemical composition of the multipod ZnO nanostructure. Finally, the growth mechanism of the multipod ZnO nanostructures was also discussed. View full abstract»

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  • Green synthesis of highly hierarchical CaMoO4 microstructures with tunable morphologies and luminescent properties

    Page(s): 988 - 991
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (222 KB)  

    Uniform, highly hierarchical CaMoO4 microstructures with various shapes have been fabricated on a large scale by means of green solution-based synthesis without adding any surfactant in a pure water reaction system. The shape and size of the as-prepared architectures can be tuned effectively by controlling the reaction temperature and pH value of the reaction solution. The photoluminescence spectra display a strong blue emission of CaMoO4 microstructures and show acidic reaction solution. The higher reaction temperature is in favour for much stronger optical properties of the prepared hierarchical CaMoO4 microstructures. This Letter sheds some light on the design of well-defined highly hierarchical CaMoO4 microstructures with tunable optical properties and explores the potential applications of the obtained architectures in an optical device. View full abstract»

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  • Very high sensitivity ZEP resist using MEK:MIBK developer

    Page(s): 992 - 994
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (263 KB)  

    Low throughput is the major drawback for electron beam lithography. Chemically amplified resists that have high sensitivity are often used to keep the exposure time within practical limit. In this Letter the authors show that the popular non-chemically amplified electron beam resist ZEP-520A can achieve 2.6 C/cm2 sensitivity when using methyl ethyl ketone:methyl isobutyl ketone developer and 5 keV exposure, though at the cost of reduced contrast compared to standard developers xylene, n-amyl acetate or hexyl acetate. The achievable resolution was found to depend strongly on the resist's adhesion to the substrate or under-layer and thus obtained 40'nm half-pitch resolution using ZEP resist spun on a layer of anti-reflection coating that was treated by oxygen plasma. View full abstract»

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  • Synthesis and electrocatalytic property of Ni(OH)2 nanoplates for H2O2 reduction

    Page(s): 995 - 997
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (198 KB)  

    β-Ni(OH)2 nanoplates were prepared by hydrothermal process. The products are characterised in detail using multiform techniques such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction and energy-dispersive X-ray analysis. The results show that the products are hexagonal β-Ni(OH)2 nanoplates with the thickness of 20-40-nm and side length of 100-200-nm. Electrocatalytic property of the prepared --Ni(OH)2 nanoplates was characterised by cyclic voltammetry (CV). CV results indicate that β-Ni(OH)2 nanoplates exhibit a remarkable electrocatalytic activity for the H2O2 reduction. Furthermore, the obtained β-Ni(OH)2 nanoplates have been employed as electrode materials for electrochemical sensing of H2O2. View full abstract»

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  • Low-temperature synthesis of flower-like TiO2 nanocrystals

    Page(s): 998 - 1001
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (375 KB)  

    Flower-like titania nanocrystals were synthesised by hydrolysis of titanium (IV) chloride at a low temperature of 70°C in 6°h, employing nanocrystal cellulose as a morphology controlling agent. Transmission electron microscope (TEM) and high resolution TEM (HRTEM) investigations revealed that the morphology of the nanocrystals was flower-like, and each flower was composed of several nanoneedles with a diameter of 15°20°nm and a length of 100°200°nm. The X-ray diffraction (XRD) results showed that the crystalline phase of the nanocrystals had a strong dependence on the mole ratio of TiCl4 to H2O. This low-temperature-prepared TiO2 exhibited high activity in the photocatalytic degradation of methyl orange in aqueous solution under high-pressure mercury lamp. This study provides a simple and high-efficient method to prepare TiO2 nanocrystals with high photocatalytic activity at low temperature. View full abstract»

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  • Supercapacitor studies on globular polypyrrole microstructures developed by a facile electrochemical route

    Page(s): 1002 - 1006
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (525 KB)  

    Micrometre-scale polypyrrole (PPy) structures are synthesised for electrochemical supercapacitor applications by a facile electrochemical route. Globular polypyrrole microstructures of size <;5<;<;m are grown on stainless steel (SS-304) substrate by electro-polymerisation of pyrrole on oxygen microbubble templates electrochemically generated and stabilised in the presence of surfactant/supporting electrolyte/dopant <;-naphthalene sulfonic acid (<;-NSA). Microstructures obtained with scan range of 0<;1.6<;V (against Ag/AgCl) are uniformly distributed over the surface with high coverage density of 5<;105 to 8×10×cm-2. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed that the formed microstructures are of β-NSA doped PPy. Scanning electron microscopy showed the uniform spread and good coverage of microstructures over the substrate. Supercapacitor properties of PPy films are investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge methods with 1.0βM KCl as electrolyte in a three-electrode electrochemical cell. Specific capacitance of 583βFg-1 is obtained, which is greater than the values (350-400-Fg-1 highest) usually reported for this material. Electrochemical impedance spectroscopy proves the supercapacitance behaviour and explains the special inductive component of impedance observed in the high-frequency regime because of the globular structures of PPy deposited. View full abstract»

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  • Spring constant analysis of the AFM rectangular, V-shaped and dagger cantilever probes

    Page(s): 1007 - 1011
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (215 KB)  

    Atomic force microscope (AFM) is primarily a tool for characterising surface topography, but there is also a strong interest in using AFM as a nanomanipulator to modify the sample surface or manipulate nanostructures. It is greatly important to understand the mechanics of AFM-based manipulation for efficient and reliable handling of nanoparticles. However, the microscopes for this kind of application have not been developed completely. During nanomanipulation process by AFM, the manipulation forces are measured according to cantilever deflection which is affected directly by spring constants of cantilever probe. Hence the cantilever probe is the most significant and sensitive component of the AFM. Typically, there are three cantilever types which are used for AFM, that is rectangular, V-shaped and dagger probes. In this Letter, the lateral, longitudinal and normal spring constants of the mentioned cantilever probes are analysed and discussed. View full abstract»

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  • Polyvinyl pyrrolidone-assisted hydrothermal synthesis of octahedral ZnFe2O4 nanoparticles

    Page(s): 1012 - 1015
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (317 KB)  

    Octahedral ZnFe2O4 nanocrystals were prepared via a polyvinyl pyrrolidone (PVP)-assisted hydrothermal route. X-ray diffractometer, field emission scanning electron microscopy and high-resolution transmission electron microscopy measurements were carried out to investigate the products' structures and morphologies. Different dosages of PVP were tested and 0.3'g was found to be the optimal dosage for the synthesis of octahedral ZnFe2O4. The selective adsorption of PVP onto the crystallographic planes should be responsible for the formation of the final octahedral particles. Moreover, magnetisation measurements revealed that these ZnFe2O4 particles possessed a high magnetic parameter with a saturation magnetisation of 44.30 emu/g and a coercivity of 299.2 Oe at room temperature. View full abstract»

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  • Out-of-plane spiral-coil inductor self-assembled by locally controlled bimorph actuation

    Page(s): 1016 - 1018
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    A method to manufacture 3D microcoils based on locally controlled bimorph actuation is reported. A simple and batch-compatible method for producing out-of-plane spiral structures is developed to create inductors whose inductances are tuned independently of their base dimensions. A 500-nm-thick Cr layer used as the stress layer is patterned on a planar Cu coil to induce plastic deformation of the coil in the vertical direction uniformly, defining the final 3D coil shape. The Cr pattern, as well as the temperature of post-fabrication annealing, is varied to achieve different levels of vertical deformation and inductance of the coils. A maximum vertical expansion of 721 μm is demonstrated to yield a 12 inductance change. The Q factor of 17 and the self-resonance at ~1.2~GHz are obtained. View full abstract»

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  • Synthesis of Ag/Cu2O hybrids and their photocatalytic degradation treatment of p-nitrophenol

    Page(s): 1019 - 1022
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (309 KB)  

    Cu2O and Ag/Cu2O hybrids with different Ag contents were synthesised by reducing AgNO3 and Cu(Ac)2 with Na2SO3 via a hydrothermal method. The as-prepared samples were characterised by X-ray diffraction, transmission electron microscopy and scanning electron microscopy technologies. The final samples were used as catalysts for degradation of p-nitrophenol in wastewater, and their catalytic parameters, including irradiation time, catalyst composition, concentration of catalyst, initial concentration of pollutant and repeatability of catalyst, were investigated in detail. The results indicated that p-nitrophenol could be effectively degraded by Ag/Cu2O hybrid with higher Ag content (such as 20 or 25% Ag). After being used nine times, the corresponding catalyst still exhibited high catalytic activity. The possible photocatalytic mechanism was discussed. The technology possesses potential application in the treatment of wastewater containing nitrophenol pollutants. View full abstract»

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  • Tip and sample flexibility effects on tapping mode (amplitude modulation) AFM measurements

    Page(s): 1023 - 1028
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (513 KB)  

    This Letter is devoted to the investigation of the tip, substrate and particle flexibility effects on the elastic deformation, the maximum repulsive force and the topography images in tapping mode (amplitude modulation) atomic force microscopy (TM-AFM). Several quantitative comparisons among the different models are presented and the effects of the elastic deformations on TM-AFM measurement are investigated. View full abstract»

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Aims & Scope

Micro & Nano Letters offers express publication of short research papers presenting research conducted at the forefront of micro- and nanoscale science, engineering and technology, with at least one dimension ranging from a few tens of micrometres to a few nanometres.

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Meet Our Editors

Editors-in-Chief
Professor Gwo-Bin Vincent Lee
National Tsing-Hua University, Taiwan

Professor Peter Dobson
University of Oxford, UK