Day 2 :
Keynote Forum
James C Sung
Synthetic Element Six (SES), Taiwan
Keynote: Large single crystal graphene manufacture
Time : 09:00-09:45
Biography:
James C Sung was responsible for diamond production technology at GE Super Abrasives, for diamond tools development at Norton. He has set the diamond grid specifications for diamond disks used worldwide for CMP of IC wafers, and helped IPO of Kink Company in Taiwan. He co-founded graphene synthetic with Huang-He worldwide, the world' largest diamond maker located in Henan China. He is now Chairman of Applied Diamond Inc., selling the most advanced CMP diamond disks-V the manufacture of next generation interconnects.
Abstract:
Graphene has phenomenal properties, such as 100X of steel’s tensile strength and 100X of copper’s electrical Conductivity. However, such properties depend on intact honeycomb structure of carbon atoms that may be present in natural graphite across nanometer scales of la or lc. In order to expand defects less graphite crystals to micron sizes honeycomb area about one million times, we invented a metal catalytic process to regrow graphite. By heat treatment of nickel metal to saturate carbon atoms as solute, la can be enlarged with temperature and time as shown below. In addition to expand the single crystals of regrown graphite, we also exfoliate such single crystals by a liquid injection method with high pressure NMP that contains suspended graphite through a diamond nozzle. The supersonic speed of liquid can suddenly expand graphite to fewer layers. In the meantime, the defect ridden region of the regrown graphite is removed.
Keynote Forum
Somnath Bhattacharyya
University of the Witwatersrand, South Africa
Keynote: Odd-frequency superconducting order parameter in Boron-doped nanocrystalline diamond films
Time : 09:45-10:30
Biography:
Somnath Bhattacharyya is a Professor in the School of Physics at the University of the Witwatersrand, Johannesburg, South Africa since 2012. After completing his doctoral degree from the Indian Institute of Science, Bangalore in 1997 he worked as a Researcher in the USA, Germany and England. In 2007 he established his new research group the nano-scale transport physics laboratory at the University of the Witwatersrand. His major interest is in the transport properties of carbon and major achievements include the demonstration of resonant tunnel devices based on amorphous carbon, gigahertz transport in carbon devices, n-type doping of nanocrystalline diamond and developing theoretical models for transport in disordered carbon. He has published four book chapters and over 70 papers in peer reviewed journals.
Abstract:
Nanocrystalline diamond films can be described as a granular superconducting system with Josephson’s tunneling between superconducting diamond grains separated by a very thin layer of disordered sp2 hybridized (i.e. graphene-like) carbon. Presently we concentrate on electrical transport properties of heavily boron–doped nanocrystalline diamond films around the superconducting transition point based on the Berezinskii-Kosterlitz-Thouless transition. The magnetoresistance (MR) of these films was found to change from negative to a positive value at a particular temperature close to this transition which is explained through the transition from weak localization to weak anti-localization effect. Through the application of a low bias current negative magnetoresistance (MR) features can be seen with periodic oscillatory features these are attributed to tunneling associated with non-s wave order parameters in a multi-junction system. Presence of an odd frequency superconducting order parameter has been claimed from pronounced zero bias conductance peak as well as spin valve-like effect in MR. Ultimately from the angle-dependent change of critical temperature as well as the MR peaks we demonstrate signature of spin triplet superconductivity in these films. The microstructure essentially forms a graphene on diamond system which has been suggested as a good candidate for topological insulator. Hence the superconducting nanodiamond heterostructures can be useful for developing topological qubits for quantum computing, some device concepts are thus discussed.
Keynote Forum
Gokul Gopalakrishnan
University of Wisconsin, USA
Keynote: Stiction assisted fabrication of single crystal silicon nanomembranes for MEMS applications
Time : 10:50-11:35
Biography:
Silicon nanomembranes are suspended sheets of single-crystal silicon, less than a few hundred nanometers thick, with areas exceeding thousands of square micrometers. Challenges in fabrication arise from strains in the silicon-on-insulator (SOI) starting material, which result in buckling instabilities in thin membranes. I recently developed a simple technique to fabricate flat nanomembranes, with thicknesses as low as 5 nm, using an elastically metastable configuration that is subsequently stabilized. The technique involves embracing, rather than avoiding, the effects of stiction, which are typically considered a detriment to MEMS fabrication. This ability to easily produce flat nanomembranes beyond the buckling threshold expands opportunities to study nanoscale properties free from the influence of a nearby substrate, but also provides a technology platform for smaller and more sensitive MEMS devices, from high-sensitivity, low-footprint pressure sensors to lab-on-a-chip devices for macromolecular separation and sensing.
Abstract:
Gokul Gopalakrishnan has a Ph.D. in Physics from the Ohio State University studying transport in two-dimensional electron gases. As a postdoctoral fellow at Harvard University, he investigated the metal-insulator transition in thin film and nanostructured vanadium dioxide. At the University of Wisconsin - Madison,Gopalakrishnan developed x-ray scattering tools to probe phonons in nanostructures. Currently at the Engineering Physics Department at the University of Wisconsin - Platteville, he is creating techniques to fabricate crystalline semiconductor nanostructures. Gopalakrishnan is on the board of the Regional Materials and Manufacturing Network, an academic-industry consortium to streamline materials research and development.
- Nanomaterials and Nanotechnology | Applications of Graphene in Energy and Biomedicals Semiconductor Materials and Nanostructures | Electrochemistry of Diamond and Nano Carbon Materials | Materials for Energy Conversion and Storage Devices
Location: Oasis C
Chair
Richard A Clark
Morgan Advanced Materials, USA
Session Introduction
Yeong-Tarng Shieh
National University of Kaohsiung, Taiwan
Title: Carbon nanotubes used as a thermal stabilizer in polymers
Time : 11:45-12:15
Biography:
Yeong-Tarng Shieh is currently a professor at Department of Chemical and Materials Engineering of National University of Kaohsiung (NUK), Kaohsiung, Taiwan. He was the department head from 2014-2017. His research interest recently includes living free radical polymerizations, stimuli-responsive polymers, preparation of carbon dioxide-switchable nanoparticle dispersion, supercritical carbon dioxide fluids technology, and applications of carbon nanotubes.
Abstract:
We began with the study of various surface-modified multiwalled carbon nanotubes (CNT) for a use as a radical scavenger. Electron spin resonance (ESR) and ultraviolet/visible spectrophotometer (UV/Vis) were used to measure radical scavenging efficiencies of the modified CNT for hydroxyl (OH.) radical and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, respectively. ESR, UV/Vis, and Raman spectra revealed that all CNT samples were good radical scavengers for both radicals and the radical scavenging efficiencies increased with increasing contents of defect sites on the modified CNT. We also investigated the radical scavenging efficiencies of silane-grafted CNTs for OH and DPPH radicals and found that the radical scavenging efficiencies decreased upon increasing the degree of the silane grafting, due to the steric bulk of the silane grafts on the surfaces of the CNTs. We used DSC to examine the effects of the silane-grafted CNTs on the exothermic peaks of the free radical–initiated crosslinking reactions of vinyl ester/styrene resins. The silane-grafted CNTs were found to retard the crosslinking reactions to various extents: a higher degree of grafting resulting in a lower crosslinking retardation. Finally, we assessed the surface-modified CNT (CNT, bmCNT, and CNT-COOH) as thermal stabilizers in poly (vinyl chloride) (PVC). Films of pure PVC, CNT/PVC, bmCNT/PVC, and CNT-COOH/PVC cast from tetrahydrofuran were subjected to thermal aging in N2 in a test tube submerged in an oil bath maintained at 180 °C for a certain time. FTIR and UV-Vis spectra and discoloration of aged PVC composites were investigated on the formation of conjugated polyene structure in PVC. The results found that all three types of CNT of small amounts (0.1 or 0.3 phr) could stabilize PVC against thermal degradation by resisting the formation of a conjugated polyene structure in the order of bmCNT > CNT > CNT-COOH. Moreover, Congo red test and pH measurement were investigated on the dehydrochlorination of PVC during the thermal aging. The bmCNT was also the most effective thermal stabilizer among the three types of nanotubes studied to resist degradation of HCl from PVC. This newly-developed PVC composite with CNT as an additive can provide an efficient route towards the development of highly thermal-stabilized PVC.
Rahul Ramamurti
Ultra Clean Technology, Canada
Title: Synthesis of nanocrystalline diamond for applications in high temperature electronics
Time : 12:15-12:45
Biography:
Rahul Ramamurti expertise in plasma physics, thin film materials, nano technology, Chemical Vapour Deposition (CVD), Physical Vapour Deposition (PVD), process development of diamond, DLC, SiC, SiCN coatings for several applications.He has a PhD in Materials Science and Engineering from the University of Cincinnati and Post Doctoral Research experience at Michigan State University/Fraunhofer U.S.A. He has worked in companies involving DLC coatings for the oil and gas industry, single crystal diamond for gem applications and oxide coatings for optical filter applications
Abstract:
High-temperature electronics and MEMS (Micro-Electro-Mechanical Systems) based on polycrystalline diamond (PCD) are promising because of its wide band gap, high thermal conductivity, and large carrier mobility. To take advantage of this opportunity, research was undertaken to develop techniques for the synthesis of both undoped and doped high quality PCD films with good surface flatness suitable for the fabrication of high temperature electronics and MEMS devices. One way to fabricate smooth films is to decrease the grain size because diamond films with large grain size bring forth problems in contact formation and device fabrication due to the large surface roughness. Consequently, there is a need to fabricate nanocrystalline films with small grain size and good smoothness. In addition, the electrical properties and conduction mechanisms in nanocrystalline diamond (NCD) films have not been sufficiently analyzed. This study also aims at achieving high resistivity nanocrystalline diamond films and to study the electrical conduction mechanism. Electrical properties of the microcrystalline and nanocrystalline diamond films were measured over a range of temperatures by fabricating capacitors using a metal-insulator-metal (MIM) configuration that could withstand temperatures up to 600 °C. Typical electrical resistivities of MCD were ~1012 W.cm while the dielectric constant was near 5.6, which was representative of natural diamond. For NCD, the electrical resistivities were of ~1011 W.cm was obtained, which was eight orders of magnitude higher than values reported by other researchers. A lower dielectric constant of 5.2 was obtained for the NCD. The electrical conduction mechanisms in undoped MCD, NCD, and nitrogen-doped films were studied. The Hill’s conduction mechanism was dominant in MCD and NCD films due to the deep-level traps present, which contributed to grain-boundary conduction. The average distances between the trap sites were found to be 11 nm for the MCD, and 5 nm for the NCD were estimated. These related to the hopping conduction across impurities present in the grain boundaries. These impurities were attributed to graphite in the PCD films. The nitrogen-doped diamond films were processed to fabricate a metal-insulator-semiconductor (MIS) structure. The resistivity of a 1% nitrogen-doped diamond was 2.8x107 Wcm. The space-charge-limited-conduction mechanism was suggested for the nitrogen-doped diamond films due to holes injected from the p-type silicon into the n-type diamond layer, and the injected holes played a role of the current carriers.
Hamid Idriss
University of Sharjah, UAE
Title: synthesis pathway for silver capped nanoparticles
Time : 12:45-13:15
Biography:
Hamid Idriss is working as Senior Chemistry Labs officer in the Department of chemistry, College of Sciences, University of Sharjah. He has a long experience in forensic chemistry and Natural products. He published two papers on Tarminalia brownii a plant used as a traditional medication for a number of diseases. He worked also as senior chemistry Laboratory in Qatar petroleum for more than 5 years. His interest shifted to the synthesis of Nanoparticles using green techniques such as plant extracts.
Abstract:
Fascinating green and cost-effective technique for the synthesis and preparation of silver nanoparticles for an easy assay for the detection of hydrogen peroxide as reactive oxygen species is described in the present study. Silver nanoparticles were capped using an extract of an algae harvested from the Arabian sea in Al-Fujairah, UAE. Nanoparticles were obtained at an optimum time of 3h under an optimum temperature of 75ËšC in a water bath shaker. The optimum pH was found to be the normal pH of the plant extract (pH= 7). The nanoparticles were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS) and Energy-Dispersive X-ray Spectroscopy (EDS). The nanoparticles were used for the sensing of hydrogen peroxide based on a colorimetric technique. The silver catalytic ability for the decomposition of hydrogen peroxide was assessed using a different concentration of AgNPs, pH effect, temperature effect and different loads of hydrogen peroxide. The red color of the silver nanoparticles solution was found to change gradually to a transparent solution with the increase of the concentration of H2O2.
Henry C de Groh
NASA Glenn Research Center, USA
Title: Electrical conductivity of a copper-metallic carbon nanotube composite
Biography:
Henry C. de Groh received his B.S. in Metallurgical Engineering from the University of Arizona in 1985, and his M.S. in Materials Sci. & Eng. from Case Western Reserve University in 1988 and has been at NASA for 32 years. de Groh is currently working on Oxide Dispersion Strengthened alloys for high temperature engines; Cu and Al carbon nanotube composites for wire; and high strength textile fibers through incorporation of CNT into silk. Mr. de Groh is married with two sons in college and likes to sail, plays guitar and sings in a band, and is a competitive Olympic weightlifter at the international level.
Abstract:
NASA is investing in advanced aviation propulsion technology that includes greater electrification of the power train. Increased electrical conductivity of power transmission wires is a technology that can substantially improve future aircraft. Both higher electrical conductivity and lower densities compared to copper and aluminum are needed. Carbon nanotubes (CNT) are being considered as a composite component to improve the electrical properties of Cu and Al. Electrical conductivity, density, and chemistry were measured for dilute Cu-CNT composites. CNT electrical conductivity depends on structure, or its chirality. All commercially available CNT consist of a mixture of approximately 66% CNT with structures that result in conductivities characteristic of semiconductors and 33% with conductivities more like metals. The average electrical conductivity of this mixture of CNT is not high enough to benefit Cu or Al. In this work composites with Cu were made using no CNT, mixed CNT, and sorted metallic only CNT. For composte wire fabrication, carbon nanotubes were coated with Cu and sealed in an evacuated pure Cu 0.25 in. diameter tube; sealed tube assemblies were hot isostatically pressed and mechanically worked into 1 mm diameter wires. The conductivity of both mixed and sorted CNT composites was 10 to 25% lower than Cu. The decrease in electrical conductivity of the composites was large compared to a bounding estimate of introducing equivalent void fractions and this suggests multiple factors were affecting the conductivity. Detailed analysis of the factors will be presented and will provide insight into future options for improving conductivity.
Eimutis Juzeliunas
Klaipeda University, Lithuania
Title: Electrochemical synthesis of photoactive carbon-carbide structure on silicon
Time : 14:45-15:15
Biography:
Eimutis Juzeliūnas is the rector of the Klaipeda University and the principal research associate at the Centre for Physical Sciences and Technology in Vilnius, Lithuania. His recent research areas include silicon electrochemistry for energy applications, environmental and microbiological degradation of metallic materials, PVD alloys, molten salt electrochemistry. The research leading to these results has received funding from the European Commission 7th Framework Programme under grant agreement PIOF-GA-300501.
Abstract:
Carbon-silicon compositions are promising to improve light harvesting performance of silicon-based solar cells. Silicon modification by carbon species could increase light absorbance and accelerate photoelectron generation. Procedures of chemical or physical vapour deposition as well as various etchings are typically used to improve antireflection performance of silicon surface. Most of these techniques, however, are not cost effective and also include hazardous reactants. We demonstrate an environmentally friendly electrochemical method of silicon surface modification by a carbon-carbide system in molten calcium chloride. Silicon-carbon-carbide compositions were obtained by polarizing silicon-silica precursor in molten calcium chloride electrolyte using a graphite anode. A reaction scheme is discussed, which includes release of oxygen from silica, its interaction with a graphite electrode and reduction of carbon dioxide by calcium metal. Structure and composition of the structures have been studied by EDX, XRD, and XPS. Semiconductor properties of the structures have been studied by Mott-Schottky characteristics, EIS and photo electrochemistry. High photo activity of the structures is demonstrated. The surfaces absorbed over 90% of white light in a broad region of wavelengths from 400 nm to 1100 nm. The proposed method offers new opportunities for production of carbon-modified silicon surfaces with superior antireflection and protective properties for solar devices or photo electrodes.
Giorgio Speranza
Fondazione Bruno Kessler, Italy
Title: Graphene and carbon nanostructures/magnesium hybrid materials for hydrogen storage
Time : 15:15-15:45
Biography:
Giorgio Speranza is a Physicist graduated at University of Trento, Italy. He is Senior Researcher at the Fondazione Bruno Kessler, Trento. He is expert in material science and characterization of material surface properties by x-ray photoelectron spectroscopy. He is active in the areas of carbon nanostructures including graphene, carbon nanotubes, carbon dots for energy and biomedical applications. He has published more than 150 papers in reputed journals and has been serving as an Editorial Board Member of reputed journals.
Abstract:
The shortage of non-renewable fossil fuels (petroleum, coal, oil, gas) and the increasing worldwide demand for energy together with the increasing widespread pollution make imperative developing new types of “green” energies sources. It is estimated that the world will need to double its energy supply by 2050 calling for new methods to produce, convert and store energy. The latter is considered as one of the most challenging objective for achieving an economy based on renewable energy sources. However, to date there are no efficient systems to store energy in large amounts. A promising solution is to accumulate energy in a chemical form using hydrogen, which can then be conveniently transported as a gas or stored. In this work we present recent developments in the research for magnesium/graphene, magnesium/carbon nanostructures hybrid materials and their hydrogen-storage properties. MgH2 was synthesized by decomposing n-Dibutyl-Magnesium leading to direct formation of MgH2 nanoparticles on the carbon substrates. TEM images show that the size of the MgH2 particles formed on these substrates can be as low as 1-5 nm in diameters. It is demonstrated that demonstrate that playing with these nanoparticles the Mg-H bond enthalpy lowers. Experimental data show that the H desorption temperature lowers from 350°C typical of bulk MgH2 to 140°C improving the system efficiency. However, still there are open challenges including of synthesis optimization, nanoparticle stabilization on the support and tank design to obtain an efficient hydrogen storage system. Perspectives for use these materials for mobile applications will be also discussed.
Kimberly Cook-Chennault
Rutgers university, USA
Title: Surface modified barium titanate for optimal dielectric properties in polymer-ceramic nanocomposite films
Time : 15:45-16:15
Biography:
Kimberly Cook-Chennault is an Associate Professor in the Mechanical and Aerospace Engineering Department at Rutgers University. She holds BS and MS degrees in Mechanical Engineering from the University of Michigan and Stanford University respectively; and a PhD from the University of Michigan, Ann Arbor. Her research interests include design of integrated hybrid energy systems and investigation of the structure-property relationships in dielectric and piezoelectric films and bulk composites for sensing/actuation and energy storage/harvesting. Cook-Chennault’s research group, the Hybrid Energy Systems and Materials Laboratory, conducts work to understand the mechanisms and processing parameters that enable control of physical material characteristics.
Abstract:
High permittivity polymer-ceramic nano composite dielectric films leverage the ease of flexibility and processing of polymers and functional properties of ceramic fillers. Physical characteristics of these materials can be tuned for application to a variety of applications, such as, advanced embedded energy storage devices for printed wired electrical boards and battery seperators. In some cases, the incompatibility of the two constituent materials; hydrophilic ceramic filler and hydrophobic epoxy can limit the filler concentration and therefore, dielectric properties of these materials. Use of surfactants and core-shell processing of composite fillers is traditionally used to achieve electrostatic and steric stabilization for adequate ceramic particle distribution. This work aims to understand the role of surfactant concentration in establishing meaningful interfacial layers between the epoxy and ceramic filler particles by observing particle surface morphology, dielectric permittivity and device dissipation factors. A comprehensive study of nanocomposites that were comprised of non-treated and surface treated barium titanate (BT) embedded within an epoxy matrix was performed. The surface treatments were performed with ethanol and 3-glycidyloxypropyltrimethoxysilan, where the best distribution, highest value of permittivity (~ 48.03) and the lowest value of loss (~0.136) were observed for the samples that were fabricated using 0.5 volume fraction of BaTiO3 and 0.02 volume fraction of silane coupling agent.