A5072339438- Silicon Carbide Semiconductor Technologies
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Semiconductor materials and devices
- Ferroelectric and Piezoelectric Materials
- Advanced Energy Technologies and Civil Engineering Innovations
- GaN-based semiconductor devices and materials
- Alkaloids: synthesis and pharmacology
- Advancements in Battery Materials
- Chemical synthesis and alkaloids
- Advanced Battery Materials and Technologies
- Magnetic and transport properties of perovskites and related materials
- Advanced Materials and Semiconductor Technologies
- Multiferroics and related materials
- Advancements in Solid Oxide Fuel Cells
- Chemical Synthesis and Characterization
- Microwave Dielectric Ceramics Synthesis
- Iron oxide chemistry and applications
- Advanced Condensed Matter Physics
- Geomagnetism and Paleomagnetism Studies
- Oxidative Organic Chemistry Reactions
- Minerals Flotation and Separation Techniques
- Diamond and Carbon-based Materials Research
- Copper Interconnects and Reliability
- Extraction and Separation Processes
The Faraday Institution
2020-2023
University of Sheffield
2020-2023
University of Liverpool
2007-2021
Alder Hey Children's Hospital
2021
Nottingham University Hospitals NHS Trust
2021
Queen's Medical Centre
2021
Liverpool Women's Hospital
2021
Aalto University
2017-2021
Widetronix (United States)
2016-2020
University of Oslo
2012-2014
Abstract Increasing concerns regarding the sustainability of lithium sources, due to their limited availability and consequent expected price increase, have raised awareness importance developing alternative energy-storage candidates that can sustain ever-growing energy demand. Furthermore, limitations on transition metals used in manufacturing cathode materials, together with questionable mining practices, are driving development towards more sustainable elements. Given uniformly high...
Abstract Li-ion batteries have revolutionized the portable electronics industry and empowered electric vehicle (EV) revolution. Unfortunately, traditional chemistry is approaching its physicochemical limit. The demand for higher density (longer range), high power (fast charging), safer EVs has recently created a resurgence of interest in solid state (SSB). Historically, research focused on improving ionic conductivity electrolytes, yet ceramic solids now deliver sufficient conductivity....
A betavoltaic cell in 4H SiC is demonstrated. p-n diode structure was used to collect the charge from a 1mCi Ni-63 source. An open circuit voltage of 0.72V and short current density 16.8nA∕cm2 were measured single junction. 6% lower bound on power conversion efficiency obtained. simple photovoltaic-type model explain results. Fill factor backscattering effects included calculation. The performance device limited by edge recombination.
Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P+N junction used to collect high-energy electrons. The electron a titanium tritide (TiH3x) foil, or integrated region formed by diffusion into titanium. specific activity directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm2. Samples with external foil produced open voltage 2.09 V, 75.47...
Combining long-range magnetic order with polarity in the same structure is a prerequisite for design of (magnetoelectric) multiferroic materials. There are now several demonstrated strategies to achieve this goal, but retaining above room temperature remains difficult target. Iron oxides +3 oxidation state have high ordering temperatures due size coupled moments. Here we prepare and characterize ScFeO(3) (SFO), which under pressure strain-stabilized thin films adopts polar variant corundum...
Bi ( Fe 1 ∕ 2 Cr ) O 3 , a recently proposed candidate multiferroic perovskite, is prepared in bulk form by high pressure solid-state synthesis. The material isostructural with polar BiFeO3 but paramagnetic at room temperature due to disorder of the Fe3+ and Cr3+ cations on B site. Mössbauer magnetization measurements show transition cooperative magnetic state below 130K.
The two-dimensional polyhedral anion network melilites La1+xSr1−xGa3O7+0.5x exhibit interstitial oxide ion conductivity. solid solution is shown to extend x = 0.64, and the variation of conductivity with investigated. At high temperatures, all these compounds adopt typical tetragonal melilite structure. When > 0.6, cooling below 600 °C results in a reversible phase transition an orthorhombic structure which reduces ionic Quenching experiments have has higher compared same composition....
The spatial ordering of interstitial oxide charge carriers in La1.64Ca0.36Ga3O7.32 melilite reduces the ion conductivity. complex pattern is produced by accommodation local structural relaxation around oxides, which extends beyond simple formation GaO5 trigonal bipyramids from GaO4 tetrahedra (see picture; brown, orange, and teal are Ga, all others O) disordered structures at low concentrations. Solid fuel cells (SOFCs) a major candidate technology for clean energy conversion because their...
We report a novel, facile and asymmetric approach to both enantiomers of the indole alkaloid deplancheine from readily available, nonracemic chiral template. The natural product its antipode are isolated with >95% ee.
Surface effects on the current instability of 4H-SiC MESFETs were studied by comparing different surface structures. The phenomenon was illustrated bias sweeping methods and recovery time measurements. A reduction in observed for gate-recessed buried-gate devices compared to nonrecessed channel-recessed devices. In addition, found have higher density breakdown voltage devices, resulting from their shorter effective gate length lower electric field distribution under gate, respectively. With...
Abstract We present a facile and highly stereoselective approach to the indolo[2,3‐ ]quinolizine ring system from readily available, non‐racemic chiral template. demonstrate potential for application of this methodology natural product synthesis through conversion template some representative indole alkaloids with high enantiomeric purity in both series. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Lamellar oxides form an important class of functional materials and are often susceptible to topotactic substitution the ions between layers. This opens up structure direct reactions with alkylammonium substituting for group 1 forcing increase in layer separation. Proton exchange is also possible mineral acids resulting protonated typically being acidic. These solid can further react bases such as alkyl amines again causing interlayer Alcohols do not readily stable ROH2+X– (R chain, X...
The isostructural double perovskites Ba2CuTeO6 and Ba2CuWO6 are shown by theory experiment to be frustrated square-lattice antiferromagnets with opposing dominant magnetic interactions. This is driven differences in orbital hybridisation of Te6+ W6+. A spin-liquid-like ground state predicted for Ba2Cu(Te1-xWx)O6 solid solution similar recent observations Sr2Cu(Te1-xWx)O6.
A two dimensional electron gas (2DEG) was observed in a C-face 3C∕4H SiC heteropolytype junction. Sheet carrier concentrations of ∼3×1013cm−2 and Hall mobility ∼314cm2∕Vs were measured at 77K. The temperature dependences concentration clearly demonstrate the presence 2DEG. Comparison with theory indicates that carriers originate from both spontaneous polarization unintentional degenerate nitrogen doping 3C-SiC, suggesting 77K 2DEG ∼700cm2∕Vs parallel bulk hopping conduction. Mobility high...
The authors report on the electronic properties of a rectifying Si face 3C∕4H SiC heteropolytype junction n+ 4H SiC. Capacitance-voltage profiling at temperatures from 4–300K showed high apparent carrier concentration. A semiclassical model was used to explain behavior. predicted spontaneous polarization-induced valence band quantum well in 3C, indicating polarization charge 9.7×1012cm−2 for SiC, good agreement with theory. formation two-dimensional hole gas predicted. Using...
A measurement of the mean e-h pair creation energy ⟨Ee-h⟩ in SiC using a scanning electron microscope is presented. Uncertainties stemming from backscattering high Z metal contacts, as well semiconductor surface, are removed by explicit through direct bombardment bare surface. reduced value ⟨Ee-h⟩=5.05eV for 4H reported, which significantly lower than previously reported values. Good correspondence with Monte Carlo simulations impact ionization was obtained.
The breakdown mechanism of SiC MESFETs has been analyzed by careful investigation gate leakage current characteristics. It is proposed that current-induced avalanche breakdown, rather than drain the dominant failure for MESFETs: thermionic-field emission and field are ON state (above pinch-off voltage) OFF (below voltage), respectively. effect Si/sub 3/N/sub 4/ passivation on voltage also investigated. decreases due to higher electric at edge compared fields before passivation. A reduction...
Scandium perovskite (Sc0.94Mn0.06)Mn0.65Ni0.35O3, synthesized at high pressure and temperature, has a triclinic structure (space group ) room temperature ambient with √2ap×√2ap×2ap α≈90(°),β≈89(°),γ≈90(°). Magnetic measurements show that the material displays Curie-Weiss behaviour above 50 K C=2.11 emu mol(-1) (μeff=4.11 μB per formula unit) θ=-95.27 K. Bond valence sum analysis of crystal shows manganese is present in three different oxidation states (+2, +3, +4), +2 state on A site...