New Publications are available for Infrared and Raman spectra in inorganic crystals
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New Publications are available now online for this publication.
Please follow the links to view the publication.Luminescence spectrum analysis of CdSe/CdS core/shell quantum dots prepared by ultrasonic irradiation
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0821
The steady-state and time-resolved luminescent properties of CdSe/CdS core/shell quantum dots are discussed. A combination of UV-Visible absorption spectroscopy photoluminescence (PL) spectroscopy and up-conversion luminescence is employed to analyze the optical characters. Near IR laser (800nm) excitation causes a blue shift of the emission peak compared to 400 nm laser excitation. It is found that up-conversion luminescence is composed of a photoinduced trapping and a band edge excitonic state. The blue shift of the emission peak is caused by the relative change in luminescence intensity between excitonic and trapping states.Comparison between PPY and PPY/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> as SAW sensitive films
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.1087
We present for the first time, to the best of authors' knowledge, a comparison investigation between the performance of polypyrrole (PPy) and PPy/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> as surface acoustic wave (SAW) sensitive films employed in situ polymerization and self-assembly method onto ST-X cut quartz substrates for testing TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> dynamically at room temperature. Both sensitive films are characterized with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopic (FT-IR) techniques. The performance of the device is analyzed in terms of frequency shift, which is real time collected by Universal Counter, as a function of the gas concentrations. For the sensitivity of both films, approximately negative frequency shifts of 30 Hz are measured for PPy to 15 ppm of NO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> but the nearly same amount of positive frequency shifts for PPy/ TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> to lOppm of NO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>. And for the selectivity of both films, about negative 90 Hz and 50 Hz frequency shifts for PPy, but positive 110 Hz and 5 Hz frequency shifts for PPy/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> are observed towards 100 ppm of NO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> and 100 ppm of H<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>S, respectively.Chemical analysis of LGS and LGT crystals by ICP-AES
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040820
In this paper we report the method used to dissolve the Langasite and Langatate crystals. Then the characterization of chemical impurities like Al, Fe, Na, Li... incorporated in the crystal during the pooling or coming from strating oxides (La<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>, Ga<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>, Ta<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> and SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>) is discussed. Finally, the comparison with the quartz crystal material has been done as well in the IR range as in term of chemical impurities.Thermoluminescence investigations in Ge-doped cultured quartz crystals
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040824
Thermoluminescence spectral characteristics of a Ge-doped quartz crystal show the presence of a temperature-glow peak at 200 EC. This peak is not observable in conventionally grown quartz undoped with Ge. Results have been compared and discussed with the near infrared spectral characteristics of natural and conventionally grown quartz crystals.Cadmium selenide quantum dot doping of organic-inorganic hybrid materials derived by sol-gel processing
http://dl-live.theiet.org/content/conferences/10.1049/ic_19971240
Nanosized phenyl-capped CdSe particles (quantum dots) were isolated, after preparation inside reversed micelles present in AOT/H<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O/heptane, and then successfully redispersed in amine-functionalised ormosils derived from 3-aminopropyl(trimethoxy)silane (i.e. SA). Doped ormosils were formed into films of a few μm thickness or small bulk samples. Host ormosils were structurally characterised by means of absorption spectroscopy, in the near- and mid-infrared ranges, and by <sup xmlns="http://pub2web.metastore.ingenta.com/ns/">29</sup>Si and <sup xmlns="http://pub2web.metastore.ingenta.com/ns/">13</sup>C solid state nuclear magnetic resonance (NMR) spectroscopy. Doped ormosils were prepared and investigated via visible spectroscopy. The size of CdSe particles dispersed into the aminosrmosil hosts was calculated using the effective mass model. (6 pages)An automatic method to extract the grating coupling coefficient in DFB lasers: evaluation of different types of fabricated lasers
http://dl-live.theiet.org/content/conferences/10.1049/cp_19971451
The grating coupling coefficients for a large number of 1.3 μm and 1.55 μm MQW DFB lasers with no, one, or two facets as-cleaved have been successfully extracted from spontaneous emission spectra.Raman imaging as a structural probe for silicon structures
http://dl-live.theiet.org/content/conferences/10.1049/ic_19951467
The Microline Focus Spectrometer (MiFS) instrument is capable of obtaining Raman spectra from a surface with sub-micron resolution and can generate profiles and images representing intensity (species concentration), frequency (stress) and bandwidth (crystallinity). This approach is an objective compromise between the time consuming and high positional stability demands of point by point sampling of the surface and the spectroscopically limited global illumination method. In addition the method does not rely upon moving optical components and thus is inherently stable. An essential element of Raman imaging is the ability to achieve a direct registration of the Raman image with a reflected light image. This is easily achieved using the MiFS approach, either by generating an image in reflected laser light from the surface as a separate experiment or by collecting reflected laser plasma line intensity simultaneously with the Raman image data. Raman images are shown from an experimental silicon structure with groups of alternate stripes of oxide and nitride on the surface. The images clearly reveal a marked change from tensile to compressive stresses as the stripe spacing is reduced to 0.5 μm. Closer analysis shows more complex variations in shift and bandwidth across and between the stripes. Silicon etching to produce complex microstructures is controlled by etch stop boundaries of boron doped silicon. Diffusion of boron into the silicon matrix results in Raman shift and bandwidth changes as the silicon lattice is adjusted to accommodate the B atoms. Raman mapping of the cross sectional edge of a silicon wafer, which has been subjected to 2 hours of B diffusion, is shown. Both the Raman shift and bandwidth images show the B doped region extending 4.5 μm into the silicon surface. (3 pages)Preparation of β-cyclodextrin-modified multi-walled CNTs and its application in capturing β-naphthol from wastewater
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0426
Multi-walled carbon nanotubes (MWCNTs) were covalently modified with water-soluble β-cyclodextrin (β-CD) through ester bond. The products cyclodextrin-modified multi-walled carbon nanotubes (MWCNTs-COO-CD) were characterised by <sup xmlns="http://pub2web.metastore.ingenta.com/ns/">1</sup>H-NMR, Fourier transform infrared spectroscopy and thermogravimetric analysis. The solubility of MWCNTs-COO-CD in water was 357.3 mg/l and no precipitates were observed after 18 months. The fluorescence spectra proved that the MWCNTs-COO-CD as a spectral probe could be used in the molecular recognition of β-naphthol (β-NOH), and the effective association constant (<i xmlns="http://pub2web.metastore.ingenta.com/ns/">K</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/">a</sub>) was calculated 2.22×10<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sup> from fluorescence spectra. By centrifugation at a speed of 16 000 rpm/min, the β-NOH with MWCNTs-COO-CD could be separated from water, collected and reused repeatedly. The results showed that the MWCNTs-COO-CD could be used to capture the aromatic pollutant such as β-NOH from wastewater. This study will widen the application of nanosupramolecule materials.Preparation of stochiometric CuInS<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> nanostructures by ultrasonic method
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0393
In this Letter, an ultrasonic method for the synthesis of CuInS<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> nanostructure with the use of no surfactants is described. This method is facile and provides an appropriate condition for the preparation of structures with various morphologies. In this study, the effect of different parameters such as type of sulphur sources, concentration of precursors, time and power of ultrasonic irradiation on the morphology and the particle size were studied. The results indicated that the type of sulphur source plays an important role in the morphology of CuInS<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>. The synthesised materials were characterised by means of X-ray diffraction, energy-dispersive X-ray analysis, scanning electron microscopy, transmission electron microscopy, infrared spectrum and photoluminescence spectroscopy. CuInS<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> nanoparticles were obtained after calcinations of the products at 350°C. The obtained results are discussed in detail.Nanostructured manganese dioxides as active materials for micro-supercapacitors
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0226
This Letter presents the design, synthesis and characterisation of nanostructured manganese dioxides (MnO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>) and their composites as electrode materials for high-capacity micro-supercapacitors. Three MnO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> samples have been synthesised by liquid-phase reaction processes, and characterised by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, surface area measurement and electrochemical tests. As a result, a preferred composite containing nano-MnO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> powder as active material, acetylene black as conductive agent and polyvinylidene fluoride as binder, exhibits a specific capacitance as high as 160 F/g in 0.2 M K<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>SO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub> aqueous solution. Then a micro-supercapacitor device with 3D interdigital structure using the composite material as electrodes has been achieved by MEMS fabrication technology. The micro-supercapacitor has well-performed capacitive behaviour under various scan rates and has a large specific capacitance of 30 mF/cm<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sup> in terms of footprint area or 50 F/cm<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sup> in terms of effective volume, which indicates that the composite is a promising material for energy storage on chips.Facile hydrothermal synthesis and electrochemical properties of hollow urchin-like α-FeOOH
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0399
Hollow urchin-like α-FeOOH was successfully prepared without template or surfactant, employing a facile route incorporating hydrothermal treatment with ammonium iron (III) sulphate solution. α-FeOOH was characterised by X-ray diffraction, thermal gravimetric analysis, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and Fourier transform infrared spectroscopy. The Ostwald ripening process was believed to be the main driving force for the formation of hollow urchin-like architectures. Furthermore, the electrochemical properties of hollow urchin-like α-FeOOH were investigated by cyclic voltammetry (CV) and galvanostatic charge–discharge measurements. The CV results implied that the capacitance was mainly associated with the redox mechanism. The specific capacitance value was 88.5 F/g calculated from the discharge curve at the current density of 0.5 A·g. The hollow urchin-like α-FeOOH shows a good electrochemical performance.Controllable synthesis and flame-retardant properties of spherical zinc borate nanostructure
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0418
A nanosphere-like zinc borate 4ZnO·B<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>·H<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O was successfully synthesised through homogeneous precipitation reaction, with hexadecyl trimethyl ammonium bromide as the surfactant. X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, transmission electron microscopy were utilised to characterise the samples. These crystal products demonstrated spherical morphology with about 50–100 nm particle size. Moreover, the effect of initial pH combined with concentration of raw materials was briefly studied. The effect of char promotion of nanosphere-like zinc borate 4ZnO·B<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>·H<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O in polystyrene as flame retardant was also revealed via the pilot study.Facile synthesis of V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>/C composite and the effect of V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> and V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>/C on decomposition of ammonium perchlorate
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0422
A V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>/carbon core–shell structured composite (V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>/C) was successfully synthesised using V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">5</sub> and glucose as the starting materials by a facile hydrothermal route and subsequent calcinations at 700°C for 2 h under Ar atmosphere. The as-obtained products were characterised by X-ray powder diffraction, energy-dispersive X-ray spectrometer, elemental analysis, Fourier transform infrared spectroscopy, Raman spectrum, scanning electron microscopy and transmission electron microscopy. Furthermore, V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> and V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>/C were explored as the additives to the thermal decomposition of ammonium perchlorate (AP), the key component of composite solid propellants. The thermal decomposition temperatures of AP in the presence of V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> and V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>/C were reduced by 49 and 73°C, respectively, which indicates that V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>/C has higher activity than that of V<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>.Influence of Al nitrate and Al chloride doping sources on structural and optical properties of sol–gel derived Al:ZnO nanoparticles
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0197
Al-doped ZnO nanoparticles have been synthesised via sol–gel method. Aluminum nitrate and aluminum chloride, as two widespread doping sources, have been compared in various Al/Zn molar ratios of 0.1, 0.5, 1, 2 and 5. After sol preparation, all samples with different Al content have been aged and then dried at 120°C. The resultant grinned powders calcined at different temperatures of 400, 500, and 600°C. X-ray diffraction (XRD) method has been used to investigate crystallisation behaviour and structural properties of samples. Less crystallinity in chloride source samples is detected compared to the nitrate source; however, identical distortion of hexagonal wurtzite unit cell in both sources was evident in XRD results. Field emission scanning electron microscopy demonstrates semisphere morphology of ZnO nanoparticles with particle size less than 60 nm. Fourier transform infrared spectroscopy was conducted to find possible chemical reactions and complexes during the sol–gel process in different Al source samples. UV-vis spectroscopy was carried out to find optical properties of the Al:ZnO samples. The results represent different optical properties in Al chloride and Al nitrate sources.Synthesis of γ-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> nanoparticles by homogeneous co-precipitation method
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0310
Pure maghemite (γ-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>) nanoparticles were prepared via so-called homogeneous co-precipitation method using urea and ammonia as precipitation agent for ferrous and ferric ions at ambient temperature. X-ray diffraction, energy dispersive spectrometer and Fourier transform infrared spectrophotometer revealed that the obtained product was pure γ-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>. Transmission electron microscope investigations showed the morphology of the nanoparticles were of approximate spherical shape with an average diameter of 11 nm. Magnetic measurements showed that resulting iron oxide nanopowder exhibited a characteristic ferromagnetism with a maximum saturation magnetisation of 66.83 emu/g.Adsorptive removal of chromium (VI) and phenol from aqueous solutions using carbonaceous microspheres as an adsorbent
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0205
Carbonaceous microspheres adsorbents prepared from the carbonisation process of glucose during hydrothermal treatment have been studied for Cr (VI) and phenol removal from aqueous solutions. Carbonaceous microspheres were characterised by scanning electron microscopy, energy-dispersive X-ray analysis and Fourier transform infrared spectroscopies. It was found that there were abundant oxygen-containing functional groups on the surface of the carbonaceous microspheres. The equilibrium data of the adsorption and the effect of pH, initial concentration of pollutant and temperature of solution on the adsorption of Cr (VI) and phenol by carbonaceous microspheres were studied. The carbonaceous microspheres exhibited excellent adsorption capacity for Cr (VI) and phenol.Octahedral and tetrahedral cobalt species in nanodimensional pores of mordenite zeolite as modified carbon paste electrode for determination of ascorbic acid
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0187
A new method is developed for the catalytic oxidation of ascorbic acid (AA) at zeolite-modified carbon paste electrode, doped with cobalt (II) (Co<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">2+</sup> MOR/ZME). Characterisation of Co<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">2+</sup>-loaded mordenite zeolite has been carried out by diffuse reflectance spectroscopy (DRS), Fourier transform-infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). FTIR and DRS show octahedral and tetrahedral Co<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">2+</sup> species into mordenite channels. TEM pictures reveal the formation of cobalt phyllosilicate. Cobalt (II) exchanged in zeolite-type mordenite acts as a catalyst to oxidise AA. The modified electrode lowered the overpotential of the reaction by ∼500 mV. The mechanism of electrochemical oxidation of AA using modified electrode was investigated by cyclic voltammetry (CV) study. Results of CV using this modified electrode show one well-resolved anodic wave for the oxidation of AA, which makes it possible for determination of compound.Synthesis, stabilisation and characterisation of rhamnolipid-capped ZnS nanoparticles in aqueous medium
http://dl-live.theiet.org/content/journals/10.1049/iet-nbt.2009.0010
Capping agents stabilise the size of the nanoparticles in the range of 1–10 nm. Microbial surfactants as capping agents are beneficial replacements for chemically synthesised ones because of lower toxicity. Rhamnolipids are surfactants produced by <i xmlns="http://pub2web.metastore.ingenta.com/ns/">Pseudomonas aeruginosa</i>, having high affinity for metal ions. In this study, the authors used rhamnolipids for capping ZnS nanoparticles. The capped particles were stabilised in aqueous environment and its characteristics were studied using Fourier transform infrared spectroscopy (FT-IR), small angle X-ray scattering (SAXS), high resolution transmission electron microscopy (HR-TEM) and ultraviolet–visible spectra, fluorescence spectra. The particle Bohr radius was found to be 4.5 nm both by SAXS and HRTEM, thus proving rhamnolipid to be an effective capping agent for the synthesis of uniform nanoparticles. SAXS study not only reveals the particle size and distribution but also its self-affined agglomeration behaviour. This work is a novel method for stabilising nanoparticles in aqueous condition using biosurfactant.One-step synthesis and characterisation of chitosan-mediated micro-sized gold nanoplates through a thermal process
http://dl-live.theiet.org/content/journals/10.1049/iet-nbt_20070018
Most of the synthesising methods of gold nanoplates reported to date rely heavily on the use of chemical reducing agents such as <i xmlns="http://pub2web.metastore.ingenta.com/ns/">N</i>, <i xmlns="http://pub2web.metastore.ingenta.com/ns/">N</i>-dimethylformamide, sodium borohydride or other organic compounds. All of these chemicals are highly reactive and may pose potential biological risks. A simple, convenient and economical route for the mass synthesis of single-crystalline, micro-sized, polygonal gold nanoplates using chitosan as a reducing/capping agent is reported. The nanoplates possess well-defined shapes with sharp edges confirmed by scanning electron microscopy. The gold nanoplates are single crystals bound primarily by (1 1 1) lattice planes, as revealed by both selected area electron diffraction and powder X-ray diffraction. These large gold nanoplates had strong absorption in the near-infrared region. The concentration and molecular weight of chitosan are important factors for the morphology and size control of the final product. This facile approach may be extended to the synthesis of some other metal nanostructures.Optoelectronic and structural properties of polysilicon produced by excimer laser and furnace crystallisation of hydrogenated amorphous silicon (a-Si:H)
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_19949959
The authors report on the optoelectronic and structural properties of polysilicon produced by excimer (ArF) laser crystallisation of undoped hydrogenated amorphous silicon (a-Si:H). Micro-structure and average grain size are determined by TEM and electron diffraction. A maximum areal grain size of 0.2 µm<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sup> is observed in excimer (ArF) laser crystallised polysilicon, grain size is also demonstrated to be dependent on the a-Si:H precursor deposition temperature. UV reflectivity and FTIR spectroscopy are employed to investigate the degree of crystallinity and atomic bonding configurations. DC conductivity measurements are used to infer information on transport properties. These data are compared with studies of low-temperature (600 degrees C) furnace crystallised polysilicon.Stoichiometric effects on optical properties of cadmium sulphide quantum dots
http://dl-live.theiet.org/content/journals/10.1049/iet-cds_20070048
Size quantised cadmium sulphide (CdS) nanocrystalline thin films with different particle sizes and stoichiometric ratios were successfully grown on indium tin oxide substrates using an aqueous synthetic route. The effect of cadmium (Cd) to sulphur (S) ratio on the optical properties of CdS nanocrystalline films was investigated using EDAX, UV–vis spectroscopy, photoluminescence and Raman spectroscopy. A satisfactory stoichiometric condition was achieved for 0.13 M concentration of thiourea whereas concentrations in the range of 1–1.2% of mercaptoethanol capping agents produced values much smaller than Wannier exciton diameter for CdS grain sizes, leading to quantum confinement. Photoluminescence emission bands and Raman peaks were analysed for the physical understanding of optimum growth of CdS quantum dots.Characterisation of intrinsic and compensated defect microstructures in dilute III–V–N alloys
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_20030915
A comprehensive analysis of the Fourier transform infrared (FTIR) absorption and Raman scattering data on impurity modes is reported for the technologically important dilute ternary GaAs<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1−<i>x</i></sub>N<sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>x</i></sub>, and GaP<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1−<i>x</i></sub>N<sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>x</i></sub> (<i xmlns="http://pub2web.metastore.ingenta.com/ns/">x</i><0.03) alloys grown on GaAs and GaP, respectively, by metal organic chemical vapour deposition (MOCVD) and solid source molecular beam epitaxy (MBE). For low nitrogen concentrations in GaAs<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1−<i>x</i></sub>N<sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>x</i></sub> [GaP<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1−<i>x</i></sub>N<sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>x</i></sub>] (i.e. <i xmlns="http://pub2web.metastore.ingenta.com/ns/">x</i><0.015), most of the N atoms occupy the As [P] sublattice <i xmlns="http://pub2web.metastore.ingenta.com/ns/">N</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/">As</sub> [<i xmlns="http://pub2web.metastore.ingenta.com/ns/">N</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/">P</sub>]. They prefer, however, to move out of their substitutional sites to more energetically favourable locations at higher <i xmlns="http://pub2web.metastore.ingenta.com/ns/">x</i> values. To comprehend the large width of the localised vibrational mode (LVM) in GaAs<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1−<i>x</i></sub>N<sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>x</i></sub> near 470 cm<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">−1</sup>, the possibilities of Ga isotopes (<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">69</sup>Ga and <sup xmlns="http://pub2web.metastore.ingenta.com/ns/">71</sup>Ga) and/or intrinsic defects participating with <i xmlns="http://pub2web.metastore.ingenta.com/ns/">N</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/">As</sub> in different configurations were studied. Theoretical results for the N-local modes and its isotopic shifts are found in good agreement with the FTIR data. Although, the presence of isolated N-interstitials. (<i xmlns="http://pub2web.metastore.ingenta.com/ns/">N</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/">int</sub>) in GaAs<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1−<i>x</i></sub>N<sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>x</i></sub> is quite unlikely at higher compositions (0.03><i xmlns="http://pub2web.metastore.ingenta.com/ns/">x</i>>0.015), the formations of nonradiative complex microstructures involving N and/or intrinsic defects are energetically favourable. The impurity modes for such complex centres were predicted and the possibility of observing them by optical spectroscopy was evaluated.Controlled synthesis of hempflower-like Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres applied on the water treatment
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0163
Hempflower-like Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres were synthesised by a simple method and its structure was determined by the scanning electron microscopy, X-ray diffraction patterns and Fourier transform infrared spectrum. The effect of reaction temperature and time on the formation and size of hempflower-like Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres was further investigated in detail. These results show that the formation of Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres with hempflower-like structure strongly depends on the reaction temperature and that the size (ca. 2–10 µm) of hempflower-like Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres can be easily controlled by adjusting the reaction time. Moreover, the synthesised hempflower-like Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres were used as water treatment for the water containing with Cu(II). The adsorption capacity of Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres was as high as 35.4 mg/g. The hempflower-like Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> microspheres was expected to apply in water treatment.Synthesis, characterisation and magnetic/electrical properties of the magnesium-doped Li–Zn nanoferrites
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0148
Nano-sized magnesium-doped Li–Zn mixed ferrite system, Li<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">0.25</sub>Mg<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">0.5−<i>X</i></sub>Zn<sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>X</i></sub>Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2.25</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub> where <i xmlns="http://pub2web.metastore.ingenta.com/ns/">X</i> varies from 0 to 0.5 in steps of 0.1 has been prepared by novel solution combustion method using oxalyl-dihydrazide as capping agent and were characterised by X-ray diffraction, infrared, Mössbauer studies and transmission electron microscopy (TEM). The magnetic and electrical properties of the nanoparticles have been investigated by vibrating sample magnetometer and two-probe method, respectively, and results are compared with bulk materials. TEM and electrical studies reveal the formation of one-dimensional semiconducting nanorods that find an extensive application in lithium batteries and in the fast-paced miniaturisation of modern electronic devices. The variation in dielectric constant with frequency has been studied.Deposition of AlN thin films on Si substrates using 3C-SiC as buffer layer by reactive magnetron sputtering
http://dl-live.theiet.org/content/journals/10.1049/el_20081366
Aluminium nitride (AlN) thin films were deposited on a polycrystalline (poly) 3C-SiC layer by a pulsed reactive magnetron sputtering system. The columnar structure of AlN thin films was observed by FE-SEM. The surface roughness of AlN films on the 3C-SiC layer was 9.3 nm. The X-ray diffraction pattern of AlN films on SiC buffer layers was highly oriented at (002). Full width at half maximum of the rocking curve near (002) reflections was 1.3°. The infrared absorbance spectrum indicated that the residual stress of AlN thin films grown on SiC buffer layers was nearly negligible. The 3C-SiC intermediate layers are promising for the realisation of nitride based electronic and mechanical devices.Preparation and characterisation of nano-ATO colloid suspension
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0052
Colloidal processing has been proved to be an ideal technology for nanopowder dispersion and to be an effective way to disperse nanopowders such as TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>, ZnO, CaCO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>, Cu, TiN, and so on. Few reports that are focused on the dispersion of nano-scaled ATO powder in aqueous media. In this Letter, the nano-ATO colloid suspension was prepared with colloidal processing. Nano-ATO powders were treated in aqueous media with ultrasonic wave and γ-methacryloxypropyl trimethoxy silane (MTS) was added as the coupling agent. The plausible modified mechanism of the silane coupling agent involves the hydrolysis of MTS, condensation of hydrolysis product and formation of a covalent bond, which is confirmed by Fourier transform infrared. Factors that affect the stability of nano-ATO colloid suspension were investigated in detail. Results show that the well-dispersed nano-ATO colloid suspension can be obtained under the following optimum conditions: the ultrasonication time is 30 min; pH of the colloid suspension is controlled at 7.0; the amount of MTS is 5.0%; the reaction temperature is 60°C. The particle size of nano-ATO colloid suspension is 65.2 nm and its distribution is unimodal distribution, which is further confirmed with transmission electron microscopy.Simple preparation of Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup>-doped LaVO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub> by ethylene glycol route: a luminescence study
http://dl-live.theiet.org/content/journals/10.1049/mnl.2010.0186
LaVO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> nanoparticles were synthesised successfully through a ethylene glycol route at a low temperature of 140°C. The structural, thermal and optical properties of the prepared samples were characterised using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric and differential thermal analysis (TG-DTA) and Fourier transform infrared (FTIR) and photoluminescence spectroscopy. The XRD patterns indicate monoclinic system of pure LaVO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub> (JCPDF 70-2392). The unit cell volume calculated from XRD data shows a gradual decrease with increasing Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> concentration indicating the quantitative substitution of La<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> lattice sites by Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> in LaVO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub>. The TEM image shows rectangular-shaped nanoparticles having diameter of 11–13 nm and length of 20–22 nm. TG-DTA analysis shows no phase change up to 900°C. FTIR study reveals that the O–H stretching vibration disappeared after annealing the sample. The luminescence study of the as-prepared nanoparticles led to the confirmation that LaVO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> shows a strong red emission at 615 nm originating from <sup xmlns="http://pub2web.metastore.ingenta.com/ns/">5</sup>D<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">0</sub>→<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">7</sup>F<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> hypersensitive transition of Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> ion. The energy transfer process was further studied by kinetic decay curves of Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> upon excitation into the VO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub><sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3−</sup> ion. Optimum emission intensity is observed at 7 at.% Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup>-doped LaVO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub> nanoparticles. Above this concentration, luminescence intensity decreases because of the concentration quenching effect.Fe- and Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>C-filled carbon nanotube-aligned arrays and flower-like carbon nanostructured clusters with a high coercivity
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0597
Fe- and Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>C-filled carbon nanostructures were synthesised by simply catalytically pyrolysing ferrocene and acetonitrile. The novel hybrid structures fabricated were thoroughly characterised by X-ray diffraction, scanning and transmission electron microscopy, electron energy loss spectroscopy, Raman spectroscopy and magnetic measurement. Aligned arrays of Fe- and Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>C-filled carbon nanotubes (CNTs) and flower-like Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>C-filled <i xmlns="http://pub2web.metastore.ingenta.com/ns/">N</i>-doped multi-branched CNTs clusters were revealed. High coercivity of 670 Oe for the flower-like nanostructures was observed, and the possible mechanism for coercivity enhancement was discussed.Low temperature VUV-assisted oxidation of Ge
http://dl-live.theiet.org/content/journals/10.1049/el_19980072
Direct photo-oxidation of germanium at temperatures < 400 °C using vacuum ultraviolet (VUV) radiation from an excimer lamp has been investigated. The oxidation rate of 0.1 nm/min is significantly faster than conventional thermal oxidation. Single wavelength ellipsometry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy measurements indicate that the grown layers are stoichiometric GeO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>.Raman emission in porous silicon at 1.54 µm
http://dl-live.theiet.org/content/journals/10.1049/el_20045284
There have been many reports regarding visible luminescence and light emission at 1.54 µm, at room temperature, from porous silicon and from Er-doped porous silicon, respectively. Described is a different approach, based on Raman scattering in porous silicon, to generate radiation at 1.54 µm. Preliminary experimental results regarding Raman emission in porous silicon samples at 1.54 µm are also reported.Characterisation, analysis and optical properties of nanostructure ZnO using the sol–gel method
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0681
Nanostructure ZnO was grown on thin aluminium layer, deposited on silicon substrate using the sol–gel method. The surface morphologies of nanostructure ZnO at different precursor concentrations were studied using scanning electron microscopy. Raman spectroscopy suggested that nanorods started to grow along with nanoflakes at a precursor concentration of 50 mM and the density of the nanorods significantly increases when the concentration was raised to 75 mM. Raman spectra were intensified and red shifted with the increment of precursor concentration. Optical properties of refractive index and optical dielectric constant are investigated. The structural defects at lower level of precursor were probably due to the hypoxic environment, whereas the red shift of Raman spectra was due to the structural change of ZnO nanocrystals.Synthesis of neutral SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> hydrosol and its photocatalytic degradation of nitric oxide gas
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0331
A neutral transparent SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> composite hydrosol was prepared by a coprecipitation-peptisation method using titanium tetrachloride and SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> hydrosol as raw materials. The prepared SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> hydrosols were characterised by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. The evaluation of photocatalytic activity for nitric oxide degradation showed the optimal weight ratio of SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> is around 1.5. After heating at 700°C for 1 h, the prepared SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> hydrosol exhibits much higher photocatalytic activity than the commercial TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> materials, Degussa P25 and ONID TH. The presence of Ti–O–Si bond in the composite hydrosol results in its good thermal stability. The prepared transparent SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> hydrosols were stable without agglomeration or gelation after storage at room temperature for over 1.5 years. The neutral SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>/TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> hydrosol could be used as the coating material applying for glass or ceramic building materials which must be treated at high temperature.Relationship between the size of SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> nanospheres and the structure colour
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0124
According to the emerging requirement in the nanofabrication field of obtaining the quantitative relationship between the nanostructure and the colour exhibited, a sphere-size colour model has been proposed and proved by experiments. The photonic crystal structures of SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> nanospheres with different diameters are fabricated on glass substrate by the self-assembly method. Simulation is carried out by thin film principle using the plane segmentation method, and a model is fitted to express the relationship between the peak wavelength and the diameter of the nanospheres. The result shows good agreement with that by the improved Bragg equation, and matched the experimental results quite well. Thus, the characteristics of its colour can be determined by the spectra obtained and the colorimetric principle. Finally, according to the model, the linear relationship between the sphere size and the peak wavelength, namely the colour of the sample, has been built.Synthesis and characterisation of CuO nanorods via a hydrothermal method
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0341
CuO nanorods were synthesised on a large scale via a simple hydrothermal method. CuCl<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>·2H<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O and cetyltrimethylammonium bromide (CTAB) were used as the copper source and surfactant, respectively. The microstructure and morphology of the CuO nanorods were examined by X-ray diffraction, Raman spectrum, field-emission scanning electron microscopy, transmission electron microscopy (TEM) and UV–vis spectrum. The CuO nanorods were monoclinic, and their diameter and length ranged from 20 to 30 nm and 150 to 200 nm, respectively. High resolution TEM and selected area electron diffraction results indicated that the CuO nanorods grow along the [010] direction. A possible growth mechanism for the formation of CuO nanorods was proposed. The concentration of surfactant CTAB in the solution was found to be a critical factor on the CuO morphology during the hydrothermal stage. The bandgap of the CuO nanorods was calculated to be 2.01 eV from the UV–vis spectrum.Economical and simple fabrication of rod-like hydroxyapatite nanocrystal with good dispersity and crystallinity
http://dl-live.theiet.org/content/journals/10.1049/mnl.2010.0041
The homogeneous hydroxyapatite rod-like nanocrystal was prepared through an economical and simple route under gentle conditions by the aqueous chemical method. The high-resolution transmission electron microscope (HRTEM) displayed that the products were well-dispersed nanorods. The diameter of the nanorods was 4±0.1 nm and the length was 20±0.8 nm. The corresponding selected area electron diffraction (SAED) analysis demonstrated that the products were crystalline. Additionally, both X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) spectra indicated the characteristic peaks of hydroxyapatite. Moreover, the energy dispersive system (EDS) analysis demonstrated the Ca/P ratio of the product was 1.67, which was in consistent with commercial hydroxyapatite.Core/shell Y(OH)CO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup>/YBO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> phosphors with sphericity, submicrometre size and non-aggregation characteristics
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0241
Core/shell Y(OH)CO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup>/YBO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> composites with a well-defined spherical shape and narrow size distribution were fabricated through a simple hydrothermal process for the first time. Y(OH)CO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup>/YBO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> composites can be obtained via Y(OH)CO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> colloidal spheres partly reacted with H<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>BO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>, with the morphology well-retained. Under UV excitation, the core/shell Y(OH)CO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup>/YBO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> phosphor emits the typical orange-colour light originating from the <sup xmlns="http://pub2web.metastore.ingenta.com/ns/">5</sup><i xmlns="http://pub2web.metastore.ingenta.com/ns/">D</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/">0</sub>→<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">7</sup><i xmlns="http://pub2web.metastore.ingenta.com/ns/">F</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/"><i>J</i></sub> transitions of the YBO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Eu<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> shell. The spherical particles might have potential application for high resolution screens, displays and flat panels.Facile hydrothermal synthesis and electrochemical properties of flowerlike α-FeOOH
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0511
Flowerlike α-FeOOH products were successfully prepared through hydrothermal treatment of ammonium iron (II) sulphate solution without extra template or surfactant. The as-prepared products were characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and Fourier transform infrared spectroscopy. It was found that the reaction temperature and time were critical for the formation of flowerlike α-FeOOH products. The results revealed that the flowerlike α-FeOOH was single-crystal structure in nature. Furthermore, the electrochemical properties of flowerlike α-FeOOH were investigated by cyclic voltammetry and galvanostatic charge–discharge measurements. A pair of electrochemical redox peaks presenting on each cyclic voltammogram indicated the existence of Faradic process, which was a signature of pseudocapacitance. The shape of charge–discharge curve displayed typical characteristics of Faradic deposition. Flowerlike α-FeOOH showed a good electrochemical performance, which may be a promising candidate as electrode material for supercapacitors.Study of hydrophobic SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> films on enamel substrate via sol–gel process
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0143
In this Letter, sol–gel was used to prepare hydrophobic films on the enamel substrate. Using tetraethoxysilane (TEOS) as the precursor, which was combined with dimethyldichlorosilane (DDS), films with SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> nanoparticles were coated on the enamel substrate, which make the droplets contact angle increase to over 110°. Fourier transform infrared spectroscopy and field emission scanning electron microscope were used to determine the elements and structure of hydrophobic film on the enamel substrate. It was found that SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> nanoparticles were beneficial to increase surface roughness while –CH<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> incorporated could decrease the film surface energy. The high surface roughness and low surface energy make it a hydrophobic performance which brings a new value to the application of enamel materials.Facile synthesis and luminescence properties of Gd<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Tb hollow microspheres
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0386
Uniform Gd<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Tb hollow microspheres have been successfully prepared via a urea-based homogeneous precipitation technique with colloidal melamine formaldehyde (MF) microspheres as templates followed by a subsequent calcination process. X-ray diffraction and Fourier transform infrared spectroscopy results show that the MF templates can be effectively removed, and the amorphous precursor has been converted to crystalline Gd<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Tb during the annealing process. Scanning electron microscopy and transmission electron microscopy images indicate that the Gd<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Tb hollow spheres inherit a spherical shape and good dispersion of MF templates, and the shell of the hollow spheres is composed of a large amount of uniform nanoparticles. The as-obtained Gd<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Tb microspheres with a spherical shape and hollow structure are uniform in size and distribution, and the thickness of the shell is about 110 nm. The Gd<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub>:Tb<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> hollow microspheres exhibit bright strong green emission corresponding to the <sup xmlns="http://pub2web.metastore.ingenta.com/ns/">5</sup>D<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">4</sub>→<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">7</sup>F<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">5</sub> transition of the Tb<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">3+</sup> ions luminescence under ultraviolet light excitation, which might find potential applications in fields such as drug delivery or biological labelling because of their excellent dispersing and luminescence properties.Functionalisation of aligned carbon nanotubes with nitric acid vapour
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0357
Millimetre high aligned carbon nanotubes (ACNTs) were functionalised by nitric acid vapour at low temperature with the formation of carbonyl and carboxyl functional groups. Samples were analysed using a scanning electron microscope (SEM), EDX, Fourier transformed infrared (FTIR), Raman and X-ray photoelectron spectroscopy (XPS). Depending on the temperature and reaction time, the treatment can lead to uniform sidewall functionalisation preserving the alignment of the ACNT ‘forest’, to random destruction, leading to significant modification of the morphology of the ACNT ‘forest’, or in some cases to cutting off the ACNTs from the substrate. Influence of the treatment duration and temperature on samples morphology and oxygen-to-carbon ratio are discussed.Temperature dependence of gas-detection sensitivity of InGaAsSb/AlGaAsSb distributed feedback lasers at 2396 nm
http://dl-live.theiet.org/content/journals/10.1049/el.2011.3369
The HF gas detection sensitivity of GaSb-based distributed feedback lasers was studied in order to evaluate the potential use of operating temperature to control the laser output power in field applications. Measurements were made in the 2<i xmlns="http://pub2web.metastore.ingenta.com/ns/">f</i> wavelength modulation spectroscopy mode to monitor a prominent HF absorption feature at 2396 nm. An Allan variance analysis indicates that the best sensitivity is obtained when a larger thermoelectric current is applied to maintain temperature control by actively heating or cooling the laser. The reduced detection sensitivity for a setpoint near the ambient laser operating temperature is similar to that obtained without active temperature control.Intersubband transition in InGaAs/AlAsSb/InP coupled double quantum well structures optimised for communication wavelength operation
http://dl-live.theiet.org/content/journals/10.1049/el_20001354
InP based InGaAs/AlAs/AlAsSb coupled double quantum well (CDQW) structures have been developed for intersubband transition (ISBT) in the near-infrared region for operation at communication wavelength. ISBT in CDQWs is influenced by the well and barrier width, and by the carrier population in the ground subband state governed by the doping level or the carrier temperature. ISBT at 1.3 and 1.55 µm can be achieved in 1.0 nm AlAs barrier coupled InGaAs/AlAsSb DQW with well widths 2.1 nm doped to 10<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">18</sup> cm<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">-3</sup>, and 2.7 nm doped to 10<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">18</sup> cm<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">-3</sup>, respectively.Compound Hertzian chain model for copper–carbon nanocomposites' absorption spectrum
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0014
The infrared range optical absorption mechanism of carbon–copper composite thin layer coated on the diamond-like carbon buffer layer has been investigated. By consideration of weak interactions between copper nanoparticles in their network, optical absorption is modelled using their coherent dipole behaviour induced by the electromagnetic radiation. The copper nanoparticles in the bulk of carbon are assumed as a chain of plasmonic dipoles, which have coupling resonance. Considering nearest neighbour interactions for this metallic nanoparticles, surface plasmon resonance frequency (ω<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">0</sub>) and coupled plasmon resonance frequency (ω<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1</sub>) have been computed. The damping rate against wavelength is derived, which leads to the derivation of the optical absorption spectrum in terms of ω<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">0</sub> and ω<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1</sub>. The dependency of the absorption peaks to the particle size and the particle mean spacing is also investigated. The absorption spectrum is measured for different Cu–C thin films with various Cu particle size and spacing. The experimental results of absorption are compared with the obtained analytical ones.Hydrothermal synthesis of urchin-like ZnO and ZnO/ZnS heterogeneous architectures
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0586
Urchin-like ZnO and ZnO/ZnS heterogeneous architectures were synthesised by a facile, inexpensive and improved hydrothermal process without any surfactants or templates at 150°C for 16 h. The morphology and qualitative analysis of the products were characterised by X-ray powder diffraction, transmission electron microscopy, field-emitting scanning electron microscopy and Fourier transform infrared spectroscopy. The results indicate that the products are urchin-like and well crystallised. The red shift of the Zn–O vibrations in the ZnO/ZnS heterogeneous architectures is ca. 23 cm<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">−1</sup> compared to that of the pure ZnO products. The growth mechanisms of ZnO and ZnO/ZnS heterogeneous architectures were discussed in detail.Fluorescence quenching of cationic organic dye by graphene: interaction and its mechanism
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0338
Graphene, an extended conjugated system, is an efficient fluorescence quencher for various organic dyes and quantum dots. In this Letter, rhodamine 6G (R6G) was used as a typical representative probe molecule to investigate the interaction between graphene and cationic organic dye. The as-prepared graphene oxide and graphene were characterised by UV–vis spectroscopy, infrared spectroscopy and atomic force microscope, respectively. The interaction between graphene and R6G was studied by various spectroscopic techniques. The results revealed that no ground state complex was formed in the presence of graphene. The observed fluorescence quenching of R6G by graphene went through an electron transfer process. The Stern–Volmer analysis indicated that the strong ability of graphene to quench the intrinsic fluorescence of R6G was based on a dynamic quenching mechanism. The fluorescence decay analysis of R6G in the presence of graphene showed a remarkable decrease in lifetime from 4.42 to 3.94 ns, which further confirmed that photoinduced electron transfer occurred between them, and the quenching of R6G by graphene was dynamic in nature.Preparation of carboxylate-intercalated layered double hydroxides using mixed hydroxides or oxides
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0323
The carboxylate-intercalated layered double hydroxides (LDHs) were prepared using mixed hydroxides or oxides under a hydrothermal or refluxing reaction. The structure of the intercalated LDHs was confirmed by X-ray diffraction patterns and Fourier transform infrared spectra. The influence of preparation conditions on the morphology of the intercalated LDHs was investigated. The intercalated LDHs with high purity and crystallinity were obtained when the raw materials were freshly generated hydroxides. In the cases of oxides as starting materials, some impurities appeared.Facile synthesis and magnetic properties of cross <i xmlns="http://pub2web.metastore.ingenta.com/ns/">α</i>-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> nanorods
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0367
Novel cross α-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> nanorods were obtained by forced hydrolysis of ferric chloride in the water solution system. The as-obtained products were characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectrum, Brunauer–Emmett–Teller and vibrating sample magnetometry. XRD results revealed that the product exhibited α-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> phase. A comprehensive TEM analysis revealed that the cross structures consisted of α-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> nanorods with an average length of 400 nm and diameter of about 75 nm. Magnetic hysteresis measurement reveals that the novel cross α-Fe<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub>O<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">3</sub> nanorods display weak ferromagnetic behaviour with a remanence of 0.115 emu/g and a coercivity of 491.5 Oe at room temperature.Wideband anti-reflective micro/nano dual-scale structures: fabrication and optical properties
http://dl-live.theiet.org/content/journals/10.1049/mnl.2011.0487
This Letter reports the fabrication and optical characteristics of large-area wideband anti-reflective micro/nano dual-scale (MNDS) structures. Microstructures, including inverted pyramids and V-shaped grooves, with controllable geometry sizes (e.g. width, pitch and depth) are fabricated by anisotropic wet etching of silicon. Highly dense arrays of high-aspect-ratio nanostructures are then formed atop those microstructures by an improved maskless deep-reactive ion etching process. Compared with the black silicon surface made of nanostructures only, these MNDS structures further reduce the optical reflectance to less than 0.6%, and the total light absorption has almost reached 95%. More importantly, by combining the light trap of microstructures and the anti-reflectance of nanostructures, these MNDS structures can efficiently suppress the reflectance of incident light at a wideband range of wavelengths from the ultraviolet, through the solar spectrum, to the near-infrared region (i.e. from 200 to 2500 nm).Strong normal-incidence infrared absorption and photo-current spectra from highly uniform (In,Ga)As/GaAs quantum dot structures
http://dl-live.theiet.org/content/journals/10.1049/el_19980589
The authors report normal-incidence infrared absorption in the wavelength range 12 – 14 µm and low temperature (40 K) photo-current spectra from an (In,Ga)As/GaAs quantum dot structure. The basic structure consists of 20 periods of highly uniform (In,Ga)As/GaAs dot arrays. The strong room temperature absorption indicates the high quality of the superlattice structure; this is considered to be very promising for the fabrication of high performance, long wavelength photodetectors.Hydrothermal synthesis and characterisation of potassium/sodium titanate nanofibres at different temperatures
http://dl-live.theiet.org/content/journals/10.1049/mnl.2012.0376
Various sized nanofibres (800 nm–5 µm in length and 15–50 nm in diameter) and nanosheets are synthesised from anatase powder (particle size; 300–400 nm) using a simple hydrothermal approach in the concentrated KOH and NaOH mixed solution. The products are analysed by a range of methods including powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and UV–vis spectrophotometer. It is found that the morphologies of titanate strongly depend on the hydrothermal temperature, in which alkali plays an important role during the whole process. The result shows that the reaction activity of NaOH with TiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> is better than that of KOH, because the radius of K (1.33 Å) is significantly larger than that of Na (0.97 Å). The aspect ratio of the products becomes larger with the increase of the KOH concentration. Furthermore, with the size decrease of the titanate nanofibres samples, the results show that their UV–vis spectra are blue-shift obviously. This work has provided an effective method to synthesise titanate composite nanofibres in alkali solution, which may also be applicable to the preparation of other composite nanomaterials.