12CaO.7Al2O3 ceramic: A review of the electronic and optoelectronic applications in display devices

The alumina-based compound, 12CaO.7Al2O3, is a ceramic material with a unique cage-like lattice. Such a structure has enabled scientists to extract various new characteristics from this compound, most of which were unknown until quite recently. This compound has the ability to incorporate different anionic species and even electrons to the empty space inside its cages, thereby changing from an insulator into a conductive oxide. The cage walls can also incorporate different rare earth phosphor elements producing an oxide-based phosphor. All these characteristics are obtained without a significant change in the structure of the lattice. It is, therefore, reasonable to expect that this compound will receive attention as a potential material for display applications. This review article presents recent investigations into the application of 12CaO.7Al2O3 ceramic in various display devices, the challenges, opportunities and possible areas of future investigation into the development of this naturally abundant and environmental friendly material in the field of display.LP Displays Ltd, Blackburn, UK for partial funding of the studentship at Queen Mary, University of London. Dr Lesley Hanna of Wolfson Centre for Materials Processing, Brunel University Londo

ZnGa2O4:Mn2+ phosphors grown by Laser Floating Zone

Cubic zinc gallate (c-ZnGa2O4) has attracted the attention of the scientific community due to its potential phosphor applications, namely in field emission displays (FEDs) and other electroluminescent devices. Among other advantages, this oxide matrix shows superior thermal and chemical stability when compared to ZnS based phosphors. Most of the above mentioned works comprise nanostructures, thin films or pressed pellets while scarce information is found on bulk c-ZnGa2O4 material. In particular, no records were found regarding c-ZnGa2O4 crystal growth by the laser floating zone (LFZ) technique. In this work, crystalline fibres of manganese doped (0.01 mol %) zinc gallate were produced via LFZ in order to investigate its applicability in efficient phosphors. The transition metal ions are suitable activators and show some advantages over the widely used rare earths, namely at environmental and economic levels

Display devices: past, present and future

Display devices: past, present and futur

Ternary biogenic silica/magnetite/graphene oxide composite for the hyperactivation of Candida rugosa lipase in the esterification production of ethyl valerate

Oil palm leaves (OPL) silica (SiO2) can replace the energy-intensive, commercially produced SiO2. Moreover, the agronomically sourced biogenic SiO2 is more biocompatible and cost-effective enzyme support, which properties could be improved by the addition of magnetite (Fe3O4) and graphene oxide (GO) to yield better ternary support to immobilize enzymes, i.e., Candida rugosa lipase (CRL). This study aimed to optimize the Candida rugosa lipase (CRL immobilization onto the ternary OPL-silica-magnetite (Fe3O4)-GO (SiO2/Fe3O4/GO) support, for use as biocatalyst for ethyl valerate (EV) production. Notably, this is the first study detailing the CRL/SiO2/Fe3O4/GO biocatalyst preparation for rapid and high yield production of ethyl valerate (EV). AFM and FESEM micrographs revealed globules of CRL covalently bound to GL-A-SiO2/Fe3O4/GO; similar to Raman and UV–spectroscopy results. FTIR spectra revealed amide bonds at 3478 cm–1 and 1640 cm–1 from covalent interactions between CRL and GL-A-SiO2/Fe3O4/GO. Optimum immobilization conditions were 4% (v/v) glutaraldehyde, 8 mg/mL CRL, at 16 h stirring in 150 mM NaCl at 30 °C, offering 24.78 ± 0.26 mg/g protein (specific activity = 65.24 ± 0.88 U/g). The CRL/SiO2/Fe3O4/GO yielded 77.43 ± 1.04 % of EV compared to free CRL (48.75 ± 0.70 %), verifying the suitability of SiO2/Fe3O4/GO to hyperactivate and stabilize CRL for satisfactory EV production

A proposal for a new type of thin-film field-emission display by edge breakdown of MIS structure

A new type of field emission display(FED) based on an edge-enhance electron emission from metal-insulator-semiconductor (MIS) thin film structure is proposed. The electrons produced by an avalanche breakdown in the semiconductor near the edge of a top metal electrode are initially injected to the thin film of an insulator with a negative electron affinity (NEA), and then are injected into vacuum in proximity to the top electrode edge. The condition for the deep-depletition breakdown near the edge of the top metal electrode is analytically found in terms of ratio of the insulator thickness to the maximum (breakdown) width of the semiconductor depletition region: this ratio should be less than 2/(3 \pi - 2) = 0.27. The influence of a neighboring metal electrode and an electrode thickness on this condition are analyzed. Different practical schemes of the proposed display with a special reference to M/CaF_2/Si structure are considered.Comment: 11 pages, 5 figure

Design and process development of an integrated phosphor field emission device

An Integrated Phosphor Field Emission Device (IPFED) has been fabricated at the Rochester Institute of Technology for the purpose of developing a new, flat panel display technology. The device incorporates a new, cathodoluminescent, thin film phosphor (Ta2Zn308) developed at RIT as an anode. A cathode and control gate, both consisting of a thin layer of molybdenum are also included in the device. Electrons are tunneled from the cathode via Fowler-Nordheim tunneling to energetically strike the phosphor anode. The anode then produces light, via cathodoluminescence, which the human eye can detect. Standard semiconductor processes were utilized in the fabrication of the device. These processes include; sputtering of Zinc Oxide, tantalum, molybdenum, and quartz, deposition of chemically vapor deposited (CVD) oxide, reactive ion etching of tantalum, molybdenum, and silicon dioxide using CHF3/He, CF4/H2, or SF6 plasmas, using a G-line stepper and diazonaphthoquinone (DNQ) novolac resin resists to pattern the aforementioned materials, and utilizing a Rapid Thermal Processor (RTP). The device can be scaled from ultra high resolution (10 jim pitch or less) to standard SVGA resolution (0.28mm pitch). Bright (no way to quantify) pixels have been observed at 200nA of current at 100V of acceleration energy. The control gate which was built into the structure does not function as designed due to shorting problems between the control gate and cathode. A process for the vacuum encapsulation of the devices has also been developed. This process does not require any special alignment of a separate faceplate. Many of the known problems with other field emissive displays have been circumvented by this new design

Inorganic Nanostructured Materials for Technological Applications

Inorganic Nanostructured Materials for Technological Application