Day 2 :
Keynote Forum
John Cerne
University at Buffalo, USA
Keynote: Quantum Hall effect near the cyclotron resonance of a two-dimensional electron gas
Time : 09:30-10:10
Biography:
John Cerne completed his Batchelor’s degree in Physics at Princeton University and his PhD in Condensed Matter Experimental Physics at the University of California, Santa Barbara. He is a Physics Professor at the University at Buffalo, where is also the Director of Undergraduate Studies for the Physics Department. He has published 60 papers in refereed journals.
Abstract:
Although the fundamental nature of quantum Hall effect (QHE) involves a constant flow of carriers in topologicallyprotected edge states where backscattering is supressed, the QHE has been found to persist at terahertz (THz, ~4 meV) frequencies in various 2D systems such as graphene and semiconductor 2D electron gases. We measure the Hall conductivity of a two-dimensional electron gas formed at a GaAs/AlGaAs heterojunction in the THz regime close to the cyclotron resonance (CR) frequency using highly sensitive Faraday rotation measurements. The sample is electrically gated, allowing the electron density to be changed continuously by more than a factor of 3. We observe clear plateau like and steplike features in the Faraday
rotation angle vs. electron density and magnetic field (Landau-level filling factor) even at fields or frequencies within half a linewidth of the CR absorption. It is surpising to see QHE plateaus where the conductivity is dominated by inter-Landau level optical absorption. We have also looked for signatures of the QHE near CR in graphene at mid-infrared energies (~100 meV).
Keynote Forum
Eun-Jae Chung
Seoul National University College of Medicine, South Korea
Keynote: Bioartificial esophagus: Strategy for layered structure regeneration
Time : 10:10 - 10:50
Biography:
Eun-Jae Chung has completed his PhD from the Korea University, Seoul, Korea. He is the Associate Professor of Seoul National University, Seoul, Korea. He has published more than 30 papers in reputed journals.
Abstract:
A number of congenital and acquired disorders require esophageal tissue replacement. Various surgical techniques, such as gastric and colonic interposition, are standards of treatment, but frequently complicated by stenosis and other problems. Autologous graft therapies using tissues from colon, and small and large intestine or gastric transplantations have been attempted but have constraints like leakage, infection and stenosis at the implanted site, which leads to severe morbidity and mortality. An alternative for autologous grafts are allogenic and xenogenic grafts, which have better availability but disease transmission and immunogenicity limit their applications. Regenerative medicine approaches facilitate the use of biological constructs to replace or regenerate normal tissue function. Use of biodegradable and biocompatible scaffolds to engineer the esophagus promises to be an effective regenerative strategy for treatment of esophageal disorders. Nanotopography of the fibrous scaffolds mimics the natural extracellular matrix (ECM) of the tissue and incorporation of chemical cues and tailoring mechanical properties
provide the right microenvironment for co-culture of different cell types. Scaffolds cultured with esophageal cells (epithelial cells, fibroblast and smooth muscle cells) might show enhancement of the biofunctionality in vivo. This review attempts to address the various strategies and challenges involved in successful tissue engineering of the esophagus. Novel approaches need to be designed to allow for peristalsis and vascularization in the engineered esophagus.
Keynote Forum
Konstantinos Papagelis
Foundation for Research and Technology-Hellas (FORTH), Greece
Keynote: Mechanical strain in two-dimensional materials
Time : 11:05-11:45
Biography:
Konstantinos Papagelis is a Professor at the Physics Department of the University of Patras and collaborating Faculty Member at FORTH/ICEHT. He conducted research
for more than four years at the University of Sussex (UK), Regensburg (Germany), Bristol (UK) and Technische Universität Berlin (Germany). His current research activities
focused on the optical and mechanical properties of graphene and other 2D materials and the production of high volume fraction nanocarbon/polymer nanocomposites.
He has published more than 130 scientific articles and received the award of the John S Latsis Public Benefit Foundation in 2011. He is Member of the Editorial Board of
Scientific Reports (NPG).
Abstract:
The application of mechanical strain in single- and few-layer graphenes as well as in other two dimensional (2D) materials
(MoS2, WS2) is an important perturbation to tune their optical and electronic properties. Raman spectroscopy has
been proven a very successful technique to study the influence of mechanical strain in 2D materials under uniaxial tension,
compression or hydrostatic (biaxial) strain. The monitoring of optical phonons seems to be the clearest and simplest way to
quantify the macroscopic stress/strain imparted to 2D membranes. In this speech, recent results on the uniaxial and biaxial
Raman response of selected 2D materials will be presented and discussed. The results will be coupled by theoretical analysis
based on molecular dynamics simulations using accurate atomistic potentials. Emphasis should be given on the perspectives
in the design of graphene based nanocomposites and flexible electronics.
- Pleanary Session
Location: Frankfurt, Germany
Session Introduction
Feng-Shou Zhang
Beijing Normal University, China
Title: Collision-induced fusion of two single-walled carbon nanotubes: A quantitative study
Time : 12:10-12:40
Biography:
Prof. Feng-Shou Zhang has completed his PhD at the age of 30 years from Lanzhou University. He is Dean of the College of Nuclear Sciences and Technology of Beijing Normal University, the director of Beijing Radiation Center. He has published more than 135 papers in reputed journals and has been serving as an editorial board member of repute.
Abstract:
The coalescence processes of two (6,0) single-walled carbon nanotubes are investigated via coaxial collision based on the self-consistent-charge density-functional tight-binding molecular dynamics method. According to the structure characteristics of the nanotubes, five impact cases are studied to explore the coalescence processes of the nanotubes. The simulation shows that various kinds of carbon nanomaterials, such as graphene sheets, graphene nanoribbons, and singlewalled carbon nanotubes with larger diameters, are created after collision. Moreover, some defects formed in the carbon nanomaterials can be eliminated, and even the final configurations which are originally fragmented can almost become intact structures by properly quenching and annealing.
Chase T Ellis
U.S. Naval Research Laboratory, USA
Title: Light-matter interactions in 2D materials throughout the infrared-THz spectral regime
Time : 12:40-13:10
Biography:
Chase T Ellis completed his PhD in the Department of Physics at the University of Buffalo (SUNY) in 2013, where he studied the magneto-optical properties of mono- and multi-layer epitaxial graphene. After completing his PhD, he served as a National Research Council Postdoctoral Fellow at the U S Naval Research Laboratory (NRL) in Washington, DC, and is now a Staff Scientist in the Electronics Science & Technology Division at NRL. His current research interests focus on the photonic properties of both 2D and 3D polar-dielectric materials that support plasmonic-like resonances that operate in the long-wave infrared spectral regime.
Abstract:
Two-dimensional materials have been shown to support many remarkable electrical and optical phenomena, where for the latter, our group has demonstrated the ability to significantly modify the polarization of light with a single graphene monolayer. In this talk, I will discuss the results of magneto-optical Kerr effect measurements, which elucidate the interactions between polarized infrared light and mono-/multi-layer graphene. In general, these measurements are extremely sensitive to the number and the stacking arrangment (AA, AB, ABC, etc) of graphene layers. We also find that the graphene doping density plays a major role in turning on and off the changes in polarization, which opens up the opportunity to produce fast, graphene-based polarization modulators by employing an electrically tunable gate. In addition, I will discuss our recent work on highly anisotropic nanostructured two-dimensional materials, such as hexagonal BN pillars, which are able to strongly confine infrared light beyond the diffraction limit. When combined, these two materials systems can potentially result in nearfield polarization control.
Giuseppina Raffaini
Politecnico di Milano, Italy
Title: Importance of protein adsorption on carbon allotropes: From biomaterials to separation techniques by molecular dynamics study
Time : 13:10-13:40
Biography:
Giuseppina Raffaini received the degree in Chemistry, the Postgraduate Diploma in "Advanced School in Polymer Science G. Natta", Inter-university Master’s in Biomaterials, in 2005, and PhD in Materials Engineering at Politecnico di Milano. In 2008, she became Assistant Professor and in 2014 Associate Professor at the Politecnico di Milano. Her research interests are molecular dynamics simulations of protein adsorption on biomaterials, inclusion complexes and self-assembling of modified cyclodextrins, organic inhibitors in concrete. She is co-author of 45 original peer-reviewed ISI papers (H-index Scopus = 18), two invited reviews, and 5 contributions to books.
Abstract:
Protein adsorption on carbon allotropes is an important process in different fields. Using molecular dynamics (MD) simulations, the adsorption of an albumin fragment, the most abundant blood protein, and of two fibronectin modules, important for cell adhesion, are studied to understand the first interaction when biomedical devices interact with biological fluids. Graphene favorably interacts with proteins, while two flat planes yield better interaction inducing larger conformational changes for the softer albumin, compared to fibronectin because of its stable ï¢-sheets. Interesting is the peculiar surface ordering obtained upon adsorption. Different topographies of carbon nanostructures influence protein adsorption. Armchair SWCNTs, similar to a graphene surface having different curvature, interact with proteins both on the external and on the internal surface. Using MD simulations we found that increasing the curvature, increases the interaction strength. When encapsulated in the inner nanotube surface, proteins better interact maximizing the CNTs surface adhesion, forming non-covalent complexes with larger stability. Considering finally armchair and chiral CNTs having similar curvature, the adsorption of an albumin ï¡-helix on outer convex and on inner concave surface is studied. In the final adsorbed state, the oligopeptide maximizes its contact with the surface, displaying complexes with unlike stability. Therefore, MD simulations in this theoretical study suggest the possible separation of chiral enantiomeric nanotubes by interaction with chiral oligopeptides. Also, they suggest the possible use of aligned chiral SWCNTs as stationary phase for racemic mixtures separation, and in proteomics, because favorable protein–nanotube interaction would yield different retention times.
Yvette Hancock
University of York, UK
Title: Graphene nanodevice design and pathways to industry
Time : 14:10-14:40
Biography:
Y Hancock obtained her PhD in 2003 at Monash University in Melbourne, Australia, with specialization in Theoretical Quantum Physics and Engineering of Nanoscale Technologies. While at Aalto University in Helsinki from 2006-2009, she was the Research Manager of a large-scale collaboration with the Nokia Corporation where one of the projects that she supervised was the application of graphene in next-generation mobile technologies. Since 2009, she has been at the University of York, UK, where she leads research in developing models for realistic simulation of nanographene and for graphene device design.
Abstract:
Graphene nanosystems have vast potential to be used in the development of energy-efficient, low power and low loss devices, such as solar cells, batteries and transistors, for example. However, there remains substantial challenges in developing fabrication processes for nanographene that produce precision-designed systems for targeted applications and successful industry mass-production. Such challenges are linked to the properties of nanographene being highly sensitive to system size, edge structure, patterning and chemical functionalisation—to name just a few design parameters. Although this versatility means opportunities in materials discovery, it also presents practical difficulties in materials design and production, which can be assisted by accurate and fast simulation. In this presentation, I will give an overview of graphene nanosystems research and development, covering progress in both top-down and bottom-up methods of fabrication, as well in device modelling. On the latter, I will also present my group’s work and within this context, discuss the development of accurate simulation to advance nanographene to its full commercial potential.
Luca Camilli
Danish Technical University, Denmark
Title: Controlled formation of nano-domains in two-dimensional heterostructures
Time : 14:40 - 15:10
Biography:
Luca Camilli has completed his PhD in Physics in 2012 from University of Tor Vergata, in Rome (Italy). He later moved to Brookhaven National Laboratory (NY, USA), where he started working on two-dimensional materials under the supervision of Dr. Sutter. Currently, he is a Marie Curie fellow at the Danish Technical University (Denmark). His research interests are synthesis and applications of two-dimensional materials, especially graphene and hexagonal boron nitride.
Abstract:
Nanoscale structures are of great interest both for basic science and for potential technological applications. In particular, when two or more nanostructures are combined together, the resulting architecture – i.e., a nanoscale heterostructure
– may exhibit new properties that are different from those of the individual components. The advent of two-dimensional materials has provided the ideal platforms where such heterostructures can be envisioned. Notably, owing to their similar lattice parameters but complementary electronic properties, graphene and hexagonal boron nitride are with no doubt the optimal building blocks for fabricating novel nanoscale heterostructures. However, the ability to fabricate nanoscale domains in two-dimensional materials is extremely challenging, and a reliable synthesis protocol is still unavailable. Here, I will review the current progress in the field, with particular attention to the reports about formation of planar heterostructures, i.e. architectures where two individual two-dimensional materials are integrated within a single atomically thin sheet.
Yanjun Li
Osaka University, Japan
Title: Local dipole moment on rutile TiO2(110) surface by electrostatic force microscopy
Time : 15:10-15:40
Biography:
Y J Li has completed her PhD from the University of Tsukuba, Japan during 1998-2001. From 2001-2003, she was a Research Fellow at Institute for Molecular Science, Okazaki, National Research Institutes, Japan. From 2004-2009, she worked as Visiting Associate Professor at Osaka University, Japan and from 2010-present, as an Associate Professor at Osaka University, Japan. She has published more than 70 papers in reputed journals.
Abstract:
Au/TiO2(110) surfaces display extremely high catalytic reactivity. There are many representative models that explain the emerging catalytic activity of Au nanoclusters. It is widely accepted that the perimeter interface of Au/TiO2 is the reaction site for CO oxidation. However, the injection/extraction mechanism of electrons and the reaction process are not clarified by a comprehensive experimental description. In this study, we proposed a new method to simultaneously measuring topography, local contact potential difference (LCPD) and dipole moment distribution on TiO2(110) surface. In the experiment, the DC bias added with ac bias voltage is applied between the tip and sample. Three lock-in amplifiers are used to detect frequency shift of ω, 2ω and3ω. The contact potential difference is numerically calculated from the divided result of ω and 2ω signals and dipole moment is obtained from frequency shift of 3ω. The simultaneously measurement result of topography, LCPD and dipole moment images were obtained on TiO2(110) surface. The details will be reported in the meeting.
Oleksii Nazarov
Lashkaryov Institute of Semiconductor Physics NASU, Ukraine
Title: Low-Temperature Reduction of Graphene Oxide
Time : 15:40-16:10
Biography:
Alexei Nazarov has completed his habilitation on DrSci in Physics and Mathematics at the age of 42 years from Institute of Semiconductor Physics NASU. He is the head of department of Functional Materials and Nanostructure. He has published more than 250 papers in reputed journals and has been serving as special editor and author of 11 books and journals.
Abstract:
Reduced graphene oxide (GO) is very promising 2D material for fabrication of high conductive transparent thin films and chemical sensors. However up to now reducing of this material was performed in vacuum or in some special atmosphere at high temperature. In this work we study the electrical and structural properties of GO films after their thermal reduction at temperature not more than 250°C at room atmosphere. The GO was synthesized by Hummers’ method and transformed into water solution. The GO films were obtained by drying of the deposited solution on glass wafer. Deposited and annealed samples were measured by 4 probe method, micro-Raman spectroscopy, FTIR spectroscopy, AFM and KPSM. It was shown that in temperature range from 100 to 220°C a resistance of the GO films strongly decreased from 4x1011 to 3x106 Ohm sq. During such strong transformation of the electrical conductivity we detected extraction of water molecules and OH bonds from the material and formation C=O and C-O-C bonds. The mRS demonstrates formation of D* phonon line at 1120 cm-1 which is associated with sp3 rich phase of disordered amorphous carbons. Study by AFM and KPSM combined with heating control system shows strong changing surface potential inside of the GO flakes during annealing from 100 to 220°C, that can be associated with desorption of water molecules and OH groups, and small changing of the flakes thickness. Important thing is the absence of surface potential changing on edges of the GO flakes. The origin of observed phenomena is discussed.
Samir Farhat
Sorbonne Paris Cité University, France
Title: Plasma Enhanced Chemicial Vapor Deposition of Graphene
Time : 16:30-17:00
Biography:
Samir Farhat has completed his PhD from Institut National Polytechnique of Toulouse in France where he was awarded Léopold Escand Price and his Habilitation from Université Paris 13. He is actually Associate Professor at University Paris 13 where he developed arc discharge reactors for the synthesis of carbon nanotubes and PECVD reactors for the growth of nanotubes and graphene. He collaborated with Johnson Space Center and ONERA to develop a global understanding of the growth mechanism of nanotubes and is currently involved in parallel projects for graphene. He has published more than 65 papers and 5 book chapters.
Abstract:
Plasma-enhanced CVD (PECVD) has emerged as a versatile method to produce different carbon materials such as diamond, carbon nanotubes and graphene. High energy electrons generated by the plasma are accelerated by the electric field and enhance ionization, excitation and dissociation processes leading to a rich chemical environment and a relatively low gas temperature. In the case of graphene, growth rate is reduced but the film quality can be controlled better. In this direction, we propose a quantitative understanding of the gas phase chemistry as well as the growth mechanism in the specific conditions of PECVD. We will discuss the significant roles of process parameters in the deposition of graphene films via catalyzed decomposition of methane diluted in hydrogen. Different conditions obtained by varying plasma power, total pressure, substrate temperature, methane flow rate and catalyst nature will be experimentally analyzed via ex situ Raman spectroscopy and correlated to in situ optical emission spectroscopy measurements (OES) in order to access the rotational and excitation temperatures of the plasma as well as the relative H-atom concentration. Different modeling approaches at (0D), (1D) and (2D) will be presented to analyze the plasma environment during graphene growth. The (0D) model extends classical chemistry formulation to non-equilibrium plasma reactors that include gas, electron and vibrational temperatures while (1D) and (2D) uses more sophisticated geometries and surface chemistry. In addition, self-consistent two-dimensional model (2D) is used in order to determine auto coherently the electromagnetic field, gas and electron temperatures, heavy species, electron and ions densities distribution in the reactor. Models are validated by comparison with experimental data obtained from atomic and molecular emission providing insight regarding graphene growth under specific plasma conditions.
G Reza Yazdi
Linköping University, Sweden
Title: Growth of Epitaxial Graphene on SiC and its Sensing Application
Time : 17:00-17:30
Biography:
G Reza Yazdi has completed his PhD in (2008) from Linkoping University and Postdoctoral studies from the same university. He has published more than 40 papers and book chapters in reputed journals.
Abstract:
To develop growth conditions for cm scale monolayer (ML) graphene on SiC, a series of samples were grown on SiC substrates in argon ambient and in an inductively heated furnace. Graphene formation was analyzed in respect to step
bunching and surface decomposition energy. The result showed that the buffer layer halts the step bunching process, which means the surface energy becomes uniform all over the substrate surface after the coverage by a buffer layer. Graphene samples grown at different argon ambient pressure prove that there is an optimal argon pressure yielding a large coverage of ML graphene. The environment, temperature, and time dependence of the graphene layers also will be presented in this work. Here surface functionalization of epitaxial graphene grown on SiC was performed by two methods, i) Silver ion irradiation at four different fluence, ii) doped graphene quantum dots with Cl, B, and N, to investigate their gas sensing capabilities. As-fabricated sensors were tested at room temperature with NO2, NH3, and C6H6. The AFM study on irradiated graphene layer showed formation of hillocks, wrinkles, and folding of graphene. The gas sensing results indicated existence of an optimal fluence and consequently optimal amounts of defects, which maximize the gas sensing response towards NO2 and NH3 gases. The results for functionalization with doped GQDs showed that sensitivity towards NO2 for the GQD-sensors were clearly lower than pristine epitaxial graphene. Moreover, Cl-doped sensor showed outstanding limit of detection and response time towards C6H6 in ppb range (down to 25 ppb).
Mohsen Adeli
Lorestan University, Iran
Title: Synthesis of Well-Defined 2D Nanomaterials to Study the Mechanism of Graphene- Pathogen Interactions
Time : 17:30-18:00
Biography:
Mohsen Adeli received his Undergraduate Degree from Lorestan University (Iran) in 1996. He obtained his MS and PhD degrees from Tabriz University in 1998 and 2005, respectively. After joining Lorestan University in 2005, he added a Postdoctoral stage from the Institute for Nanoscience and Nanotechnology of Sharif University of Technology in 2007. He was promoted to the rank of Full Professor in 2013. One of his research interests is synthesis, functionalization and applications of 2D nanomaterials.
Abstract:
Understanding the mechanism of interactions between 2D nanomaterials and pathogens is vital to develop and control their antimicrobial properties1-3. This is possible when the system is well-defined. In this work, a stimuli responsive
graphene derivative with defined structure and properties is designed and synthesized and the mechanism of its interactions with E.coli is investigated. Polyethyleneglycol-block-(poly-N-isopropylacrylamide) copolymer (PEG-b-PNIPAM) with the triazine joint point was attached to the surface of graphene by [2+1] cycloaddition reaction and a photothermo responsive nanomaterial was obtained. It was found that hydrophobic interactions is one of the most important driving forces in the graphene-E.coli interface. Transformation of the functionalized graphene sheets from a hydrophilic to hydrophobic state by photo- or thermos- stimuli factors influenced their interactions with the bacteria membrane, dramatically. This study shows that interactions between graphene and pathogens could be controlled by manipulation of the hydrophobicity of their surface.
- Plenary Session
Location: Frankfurt, Germany
Session Introduction
John Parthenios
Foundation for Research and Technology-Hellas (FORTH), Greece
Title: Polymer/ graphene hybrids as building blocks for flexible touch screens
Time : 11:45-12:15
Biography:
John Parthenios is a Principal Scientist at FORTH/ICEHT, Greece with experience in physics and mechanical properties of graphene, the production of high volume fraction carbon nanotube and graphene based polymer nanocomposites with superior mechanical properties. His expertise covers the production of 2D materials such as graphene and MoS2 & WS2 under CVD conditions. He is a Distinguished Member of the Hellenic Physical Society and Co-founder of FORTH Graphene Centre. He has 90 publications in total, 23 refereed books of proceedings and more than 100 conferences.
Abstract:
Thin films supported on substrates are of technological importance and are common place in biological systems such as cell walls and hard skins on soft plant and animal tissues. Stacks of graphene that are laid onto a flat transparent polymer substrate constitute the main part of a flexible touch screen where transparent and conductive electrodes are needed. The number of stacked graphene layers defines the optical transmittance of the screen as well as the conductivity for either resistive or capacitive mode of operation. Both transmittance and conductivity are functions of the quality of the grown graphene layer and, more importantly, of its morphology after the attachment onto the target substrate. Conventional wet transferring techniques involve intermediate carrier films, and therefore several contact and separation events before the deposition of the graphene layer on the target substrate. Such processes result in a transfer-induced texturing of graphene with folds, wrinkles and cracks. In the present work, a systematic investigation is carried out for morphological, mechanical and electrical characterization of graphene stacks on PET substrates. In particular, samples consisted of one, two, three and five graphene layers (nLG) deposited onto a transparent PET film of 125 μm in thickness by the ‘bubbling’ technique were supplied by BGT materials. By means of SEM and AFM microscopies, the texturing of the PET surface after stacking sequentially a number of graphene layers was identified. The texturing of the 1LG resembles to a thin film under biaxial compression that has been buckled into wrinkles and folds. The subsequent stacking from 2LG up to 5LG results in a different pattern on the PET surface. Within this pattern the folds are broader (~150 nm) and higher (~15 nm) delineating individual domains. Uniaxial tensile tests in combination with Raman microscopy and electrical conductivity measurements were performed to assess the interlayer and the PET/layer adhesive interactions in each stacking configuration and their influence on the hybrid material conductivity. Finally, the optimum number of graphene stacks for a PET/ graphene hybrid is proposed for flexible electronic applications.
Andrey L Stepanov
Kazan Federal University, Russia
Title: Surface periodic micro-nanosctructuring of diamond by boron and silver ion implantation
Time : 12:15-12:45
Biography:
A Stepanov is with Kazan Physical-Technical Institute, Russian Academy of Sciences since 1992. During 1997-1999, he was a Research Fellow at the Sussex University, UK (the Royal Society/NATO). From 1999 to 2003, he was a Research Fellow of the RWTH in Germany (the Alexander von Humboldt Foundation). During 2003-2004, he was granted Lise Meitner Fellowship (Austrian Scientific Society) in Karl-Franzens-University in Graz. From 2004 to 2011, he was a Research Fellow in Laser Zentrum Hannover in Germany (DAAD, DFG and the AvH). In 2013, he was granted the National Scholarship of the Slovak Republic.
Abstract:
Modern tasks of integrated optics require the use of special new materials and the development of technologies for productions of components and devices based on them. One of the specific areas is diamond optics. The interest in
diamond is explained due to its radiation resistance and high thermal conductivity. Diamond Optical Elements (DOE) have a wide window transparency from 0.2 to 5 ïm. Diamond fills well at very high temperature and in aggressive chemical environments. In practice, the diamonds are used for production various diffractive optical elements as gratings, focusers, equalizers, etc. DOE can be applied with the high-power beam of the CO2-laser until the power density of the illumination up to 20 kW/cm2, to create a photonic crystal resonators to implement quantum information storage devices and to control the
radiation fluxes in the X-ray optics, for example, using diamond Bragg mirror with a reflectivity of 100% etc. The present study relates to new method for a fabrication of diffractive optical elements with diamond surface nanostructuring. The diffraction grating was obtained on diamond by implantation of boron or silver ions through a mask. In the process of implantation in the unmasked areas of the irradiated diamond was graphitized and nanostructured. The formation of periodic diffraction microstructures on the diamond surface was monitored by optical, electron and atomic force microscopy.
Kazuhiro Marumoto
University of Tsukuba, Japan
Title: Direct observation of electrically controllable spin states in single-layer graphene using electron spin resonance spectroscopy
Time : 12:45-13:15
Biography:
Kazuhiro Marumoto has completed his PhD from Osaka University and worked as an Assistant Professor at Nagoya University. He is an Associate Professor of Division
of Materials Science at University of Tsukuba, and also a member of Tsukuba Research Center for Interdisciplinary Materials Science (TIMS) at University of Tsukuba. He
has published more than 140 papers in journals, and has been serving as a Chief Editor of The Society of Electron Spin Science and Technology (SEST) and an Editorial
Board Member of Scientific Reports.
Abstract:
Graphene has been actively investigated as an electronic material owing to many excellent physical properties such as high charge mobility and quantum Hall effect due to the characteristics of a linear band structure and an ideal two-dimensional electron system. However, the correlations between the transport characteristics and the spin states of charge carriers or atomic vacancies in graphene have not yet been fully elucidated. Here, we show the spin states of single-layer graphene to clarify the correlations using an electron spin resonance (ESR) spectroscopy as a function of accumulated charge density using transistor structures. Two different electrically induced ESR signals were observed. One is originated from a Fermi-degenerate two-dimensional electron system, demonstrating the first observation of electrically induced Pauli paramagnetism from a microscopic viewpoint, showing a clear contrast to no ESR observation of Pauli paramagnetism in carbon nanotubes (CNTs) due to a one-dimensional electron system. The other is originated from the electrically induced ambipolar spin vanishments due to atomic vacancies in graphene, showing a universal phenomenon for carbon materials including CNTs. The degenerate electron system with the ambipolar spin vanishments would contribute to high charge mobility due to the decrease in spin scatterings in graphene.
Nadezhda Nebogatikova
Rzhanov’s Institute of Semiconductors Physics SB RAS, Russia
Title: Nanostructured few-layer graphene and fluorographene films for a wide range of electronic applications
Time : 14:00-14:30
Biography:
Nadezhda Nebogatikova has her expertise in the area of graphene functionalization, graphene quantum dots, suspensions and inks for 2D-inkjet printing. She has 14 publications. She along with her colleagues have found an approach to create different fluorinated graphene-based materials. Her investigations of graphene fluorination open new pathways for improving graphene-based devices with a wide range of electronic and structural properties.
Abstract:
One of the most important tasks for the graphene-based nanoelectronics development is saving graphene excellent electric properties during its nanostructuring. The most dramatical changes of electric properties are caused by dangling bonds and edge atoms. We created several types of graphene nanostructures without such defects. The first type is partially fluorinated
graphene suspensions with nanosized graphene islands embedded into a stable fluorographene matrix. Films created on the base of such suspensions exhibited a row of promising for application properties depending on the suspension fluorination degree. Moreover, we used high energy ions (26 – 167 MeV) to create a continuous graphene surface between two perforated layers. We tried to cut holes in neighboring graphene layers and to bond the chemically active atoms from different layers forming a closed structure of sp2-hybridized carbon atoms. Such approach was suggested by L.A. Chernozatonskii. Both scanning electron microscopy and atomic force microscopy demonstrate nanosized holes (20-40 nm in diameter) formed by ions irradiation. The initial ions energy determines the amount of electronic loss and the value of a sharp local temperature rise in the films. As a consequence, the type of the holes edge may be reconstructed in the range from the dangling bonds to connected edges. The formed nanostructures are very attractive as well as for nanoelectronic devices because of the appearance of the bandgap with a combination of a relatively high carrier mobility.
- Sessions: Synthesis of Graphene and 2D Materials | Graphene and 2D Materials based Nanocomposites | Graphite, Graphene & their polymer nano composites | Graphene and Graphene oxide | Graphene Modification and Functionalisation
Location: Frankfurt, Germany
Chair
John Bell
Queensland University of Technology, Australia
Co-Chair
Feng-Shou Zhang
Beijing Normal University, China
Session Introduction
Gagik Shmavonyan
National Polytechnic University, Armenia
Title: Substrates rubbing method for obtaining mono- and few layer graphene and 2D materials
Time : 14:30-14:50
Biography:
Gagik Sh Shmavonyan is Full Professor at National Polytechnic University of Armenia. He got his PhD in Physics in 1996 and DSc in Engineering in 2009 at the same university. He did Postdoc at National Taiwan University, Taiwan (2001-2002). He was a Visiting Professor at the University of Hull, UK (2000, 2003), Polytechnic of Milan, Italy (2004-2005), University of Bremen, Germany (2002, 2006), Free University Berlin, Germany (2011), Trinity College Dublin, Ireland (2012), University of Santiago de Compostela, Spain (2013-2014) and University of Cergy-Pontoise, France (2016, 2017). His current research interests are 2D atomic materials, their structures and devices. He has authored more than 100 refereed papers, 20 patents, 4 books and a chapter in a textbook for European students. His most significant reasearch awards are: Cleantech Oscar Award (2015, Silicon Valley, USA); ARPA Institute Invention Competition Awards (2013 and 2014, Los Angeles, USA).
Abstract:
An extremely simple, fast, cost-effective, transfer- and chemical-free, reliable and industrially scalable non-conventional rubbing method (substrates rubbing method) for obtaining high quality and large size mono- and few layer (MFL)
graphene, hexagonal boron nitride (h-BN) and other two-dimensional (2D) material nanostripes (NSs) consisting of arrays of quantum dots, films and hybrid nanostructures consisting of NSs and/or films on different rigid and flexible inorganic and organic substrates with atomically flat or stepped (terraced) surfaces is suggested. 2D materials are obtained manually (homemade) or mechanically (for mass production) by rubbing graphite or other layered bulk materials on dielectric, semiconducting and metallic substrates at atmospheric pressure conditions. The combination of microscopic, spectroscopic and electrical characterization techniques, i.e. optical, atomic force (AFM), scanning electron (SEM) and high resolution transmission electron (HR-TEM) microscopy, ultraviolet (UV)–visible, fluorescence (PL), X-ray photoelectron (XPS) and Raman spectroscopy, X-ray diffraction (XRD) and I-V measurements reveal the mechanism of the formation of unique 2D material NSs and films consisting of the NSs on different substrates by defining the efficient rubbing conditions, as well as the requirements to both the substrates and material being rubbed (layered bulk powder, highly ordered pyrolytic graphite (HOPG), fullerene, nanotube). The suggested ecologically clean technology, in contrast to the conventional technologies, drastically decreases the production cost and time, facilitating the making process and avoiding the use of chemicals, solutions and any device, thus paving the way to industrial-scale 2D material production and new applications in next generation
ultrathin, lightweight flexible, hybrid and wearable electronics, as well as 2D material enhanced products.
Zari Tehrani
Swansea University, UK
Title: Graphene Sensors for Healthcare Applications
Time : 14:50-15:10
Biography:
Senior Researcher,College of Engineering, Swansea University, Singleton Park, Swansea, UK
Abstract:
Rapid detection of low concentration of specific analytes in small sample volumes is critical in early point-of-care diagnosis. Graphene’s unique electron transport properties and large surface area due to its atom-thick 2D structure makes it a promising candidate for biosensors. Recently, the graphene sensor technology promise to be a vision technology in next generation electronics and sensors - due to graphene’s exceptional electronic properties and aptitude for chemical modification. Graphene based biosensors have been developed, based on chemically functionalised graphene microchannels using wide range of graphene such as epitaxial graphene, screen printed graphene sensors and on CVD graphene. Several different chemical functionalisation methods for graphene have been evaluated and used in sensing applications of graphene, electrochemical and CHEMFET sensors. Direct and indirect (using a modification of an adsorbed layer or polymer film on top of the graphene) functionalisation techniques including diazotisation, aminosilane chemistry and non-covalent functionalisation methods were developed and reviewed. The chemical functionalisation plays a significant role in dictating the sensitivity of the device by improving the attachment of "bioreceptor" molecules, capable of specific and selective detection of target biomarkers. The technology is now being applied to detect blood based biomarkers related to Alzeimers Disease. Changes in the current-voltage characteristics of the graphene sensors are used to detect proteins.
Daniele Perilli
Università di Milano-Bicocca, Italy
Title: Water at the Interface Between Defective Graphene and Cu or Pt (111) Surface
Time : 15:10-15:30
Biography:
Daniele Perilli obtained his MSc in Chemistry in 2017 at the University of Milano-Bicocca with a thesis on the computational study of defective graphenic systems supported on metals. His work of bachelor and master thesis has been included in three international peer-reviewed articles. He is now pursing his PhD degree in Materials Science under the supervision of Prof. Cristiana Di Valentin. His current research focuses on quantum mechanical simulations of low dimensional materials, in particular electronic structure and catalysis of metal supported and defective h-BN sheet.
Abstract:
The presence of defects in the graphenic layers deposited on metal surfaces modifies the nature of the interaction. Unsaturated carbon atoms, due to vacancies in the lattice, form strong organometallic bonds with surface metal atoms that highly enhance the binding energy between the two materials. We investigate by means of a wide set of dispersion-corrected density functional theory calculations how such strong chemical bonds affect both the electronic properties of these hybrid interfaces and the chemical reactivity with water, which is commonly present in the working conditions. We compare different metal substrates (Cu vs. Pt) that present a different type of interaction with graphene and with defective graphene. This comparative analysis allows us to unravel the controlling factors of water reactivity, the role played by the carbon vacancies and by the confinement or “graphene cover effect”. Water is capable of breaking the C-Cu bond by dissociating at the undercoordinated carbon atom of the vacancy, restoring the weak van der Waals type of interaction between the two materials that allows for an easy detachment of graphene from the metal, but the same is not true in the case of Pt, where C-Pt bonds are much stronger. These conclusions can be used to rationalize water reactivity at other defective graphene/metal interfaces.
Rashmi Chawla
University of Science and Technology Murthal, India
Title: GO/rGO: Structural and Electrical Correlation through Experimental and Software Simulation
Time : 15:30-15:50
Biography:
Rashmi Chawla is pursuing her PhD in the field of Graphene: 2D materials and its optoelectronic application. She is working as Assistant Professor in YMCA University of Science and Technology. She holds membership in several national and international professional bodies and serves in technical committees like Vigyan Prasar (Department of Science and Technology) in her area of research. She has published more than 20 papers in reputed journals and has been serving as an Editorial Board Member of repute.
Abstract:
Graphene oxide (GO) and Reduced Graphene Oxide (rGO) are easier to manufacture in large quantities than perfect singlelayer graphene and this quality of GO and rGO is lucrative for bulk material applications. In this paper, GO and rGO have been synthesized using chemical methods, and process parameters were examined. Further prepared GO and rGO were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. XRD patterns, Raman spectra and FTIR spectroscopy substantiate eloquent structural
changes while reducing GO to rGO. The obtained products were then analysed for their optical and electrical properties using UV spectroscopy, photoluminescence spectroscopy and four-point probe.The conductivity is measured by proposed 4-probe measuring device designed on LABVIEW software and is later on verified experimentally also. There have been minor changes in d-spacing and improvements in crystal perfection and orientation as concluded from XRD patterns. Various structural and electrical correlation in GO and rGO have also been observed and thermal impact on conductivity is shown theoretically and experimentally.
Amirmehdi Saedi,
Leiden University, Netherlands
Title: Synthesis of two-dimensional materials via liquid metal catalysts route: Instrument development for in situ investigation
Time : 15:50-16:10
Biography:
Amirmehdi Saedi has completed his PhD at the University of Twente (Physics of Interfaces and Nanostructures). He is currently Postdoctoral Fellow at the Leiden Institute of Chemistry (Catalysis and Surface Chemistry) in the Netherlands. His research background covers a diverse collection of topics within Surface Science, including Electrochemistry, Nano-Materials, Thin Film Growth, and Catalysis.
Abstract:
Two-dimensional materials (2DMs) hold great promise for future applications in many technological areas. However, the main hurdle against practical tilization of 2DMs is the lack of effective mass production techniques to satisfy the growing qualitative and quantitative demands for scientific and technological applications. The current state-of-the-art synthesis method of 2DMs involves the dissociative adsorption of gas-phase precursors on a solid catalyst. This process is slow by nature, inefficient, and environmentally unfriendly. Our analysis and recent experimental evidence suggest that using liquid metal catalysts (LMCats) instead of solid ones bears the prospect of a continuous production of 2DMs with unprecedented quality and production speed. However, the current knowledge about the catalytic properties of LMCats is extremely poor, as they had no technological significance in the past. In fact, there exist no well-established experimental facilities, nor theoretical frameworks to study the ongoing chemical reactions on a molten surface at elevated temperatures and under a reactive gas atmosphere. Our aim is to establish a central lab at the ESRF in Grenoble, under supervision of several scientific/engineering teams across Europe to develop instrumentation capable of studying the ongoing chemical reactions on the molten catalyst, with the goal to open two new lines of research, namely in situ investigations on the catalytic activity of LMCats in general, and unraveling the growth mechanisms of 2DMs on LMCat surfaces in specific. Gaining this knowledge would be the key toward establishing the first efficient mass production method for 2DMs using the new LMCat technology.
Elena Iuliana Bîru
University Politehnica of Bucharest, Romania
Title: New approach in graphene-oxide polybenzoxazine nanocomposites synthesis
Time : 16:40-17:00
Biography:
Elena Iuliana Bîru has completed her MSc studies in Polymer Science and Engineering at University Politehnica of Bucharest, Faculty of Applied Science and Materials Science. She is a PhD student since 2016 at University Politechnica of Bucharest, Advanced Polymer Materials Group. Her main research field refers to covalent functionalization of graphene oxide with polymers.
Abstract:
In this work, we propose an original route to synthesize new benzoxazine – functionalized graphene oxide monomers (GOBZ). The new method consists in the growth of the benzoxazine rings directly on the graphene oxide (GO) surface. In order to obtain the GO-BZ monomers the chlorination method using SOCl2 was employed. Firstly, the carboxylic groups from graphene oxide surface are acylated and then treated with a hydroxyamine (TYR) in order to synthesize hydroxilic groups on graphene oxide . These groups react further on with amine and formaldehyde to give the benzoxazine rings (Figure 2) which are polymerized in order to produce the polybenzoxazine matrix which will include the graphene oxide`s exfoliated layers within the polymer. Finally a nano structure with strong bonds between the graphene sheets and the polybenzoxazine chains is achieved. The formation of multi-benzoxazine functionalized graphene oxide was checked by FT-IR, 1H-NMR, TGA, Raman
spectrometry, XRD, HR-TEM and XPS analysis. The benzoxazine rings previously obtained will be subsequently polymerized to produce the polybenzoxazine structure including the graphene oxide sheets exfoliated within the polymer mass. The benzoxazine polymerization may take place either between the rings of the same GO layer (“in-graphene” polymerization) or between the rings of two neighbors of GO layers (“out-graphene” polymerization), in the end obtaining a nanostructure with strong bonds between the graphene sheets and the polybenzoxazine chains.