Scientific Program

Conference Series Ltd invites all the participants across the globe to attend 3rd International Conference on Nanotek and Expo Hampton Inn Tropicana Las Vegas, USA .

Day 3 :

  • Track 5: Nanodevices and Nanosensors (Session 1)
Location: Salon A
Speaker

Chair

Dominique Ausserre

Universite du Maine, France

Speaker

Co-Chair

Kohki Mukai

Yokohama National University, Japan

Session Introduction

Sushil K. Misra

Concordia University, Canada

Title: The role of reduced graphene oxide capping on defect induced ferromagnetism of ZnO nanorods

Time : 09:00-09:20

Speaker
Biography:

Sushil K. Misra is a Full Professor of Physics at Concordia University, Montreal, Canada. He has done extensive experimental and theoretical research in electron paramagnetic resonance, with some 270 papers to his credit. Currently, he collaborates with ACERT (Advanced Center for Electron Spin Resonance Technology) at Cornell University. He has written numerous review articles and book chapters on EPR, and has been invited frequently as a specialist to present lectures at international conferences. He was one of the early EPR researchers invited by the People’s Republic of China as a foreign expert on EPR in 1985.

Abstract:

In this study, the effect of different numbers of layers of reduced graphene oxide (RGO) on the ferromagnetic behavior of zinc oxide-reduced graphene oxide (ZnO-RGO) hybrid architectures has been investigated. Scanning and transmission electron microscopy along with x-ray diffraction of these hybrids confirm that ZnO nanorods are wrapped with different numbers of layers of RGO in a controlled way and their hexagonal phase is unaffected by these layers. Raman and photoelectron spectroscopy of these hybrids reveals that RGO does not alter the nonpolar optical phonon E2 (high) mode and chemical state of Zn(2+) in ZnO. Electron paramagnetic resonance (EPR) spectra show that RGO passivates singly charged oxygen vacancies (VCOS) in ZnO. It correlates the passivation efficiency of VCOS to the number of RGO layers and this has been achieved up to 90% by _31 layers of RGO. Due to passivation of VCOS in ZnO by RGO, the ferromagnetic behavior (saturation magnetization and divergence between zero field cooled and field cooled) in ZnO-RGO hybrids is suppressed as compared to ZnO. Combining the EPR and magnetic behavior, a direct link between the passivation of the singly charged oxygen vacancies present on the surface of ZnO nanorods and the number of RGO layers is established.

Tomohiro Amemiya

Tokyo Institute of Technology, Japan

Title: Photonic metamaterials for InP-based optical communication devices

Time : 09:20-09:40

Speaker
Biography:

Tomohiro Amemiya received his Ph.D. degree from the University of Tokyo, Japan, in 2009. In 2009, he moved to the Quantum Electronics Research Center (QNERC), Tokyo Institute of Technology, where he is currently an Assistant Professor. His research interests are in the physics of semiconductor light-controlling devices, metamaterials for optical frequency, magneto-optical devices, and in the processing technologies for fabricate these devices. He was the recipient of the 2007 IEEE Photonics Society Annual Student Paper award, the 2008 IEEE Photonics Society Graduate Student Fellowships, and 2012 KONICA MINOLTA Imaging award.

Abstract:

Photonic metamaterials offer new opportunities for innovation in the field of electromagnetic parameter design, such as the design of permittivity ε and permeability μ. The major focus of attention is to create artificial materials with unique ε-μ values that cannot be observed in any existing media and to take advantage of these expanded parameters for better control of electromagnetic waves. Recent progress in photonic metamaterials has allowed researchers to move material properties away from the non-magnetic line μ=1 and has opened the third quadrant of the parameter space (i.e., ε<0 and simultaneously μ<0), which was previously inaccessible. One of the next trends in this field is to think of metamaterials as devices, where the structuring of metal and the hybridization with functional agents brings new functionality. Especially, introducing photonic metamaterials into actual optical communication devices poses an exciting challenge. Much effort has been expended in the development of advanced optical applications using the concept of metamaterials; leading examples of such applications include MEMS actuators with split-ring resonators and Si-based optically-controlled modulators that can perform negative-index tuning. In this talk, we report InP-based optical communication devices combined with metamaterials to show the possibility of permeability control on the semiconductor-based photonics platform. As an actual device, we demonstrate an electrically-driven permeability-controlled optical modulator, which shows great promise for using both the permittivity and permeability in semiconductor-based photonic devices.

Kohki Mukai

Yokohama National University, Japan

Title: Template method for nano-order positioning and dense packing of colloidal quantum dots

Time : 09:40-10:00

Speaker
Biography:

Kohki Mukai received Ph.D. in Electronics Engineering from Kyoto University, Japan. He is the Professor of Graduate School of Engineering, Yokohama National University. In 1994, he invented the method to grow self-assembled InGaAs quantum dots (QDs) which emit at the optical telecommunication wavelength of 1.3 and 1.55 μm. In 1999 he realized the first 1.3-μm CW lasing of QDs at room temperature. His achievements led to the world's first establishment of QD's photonic device provider, QD Laser, Inc.

Abstract:

Semiconductor quantum dot (QD) is promising for various future optoelectronic devices. One important application is the quantum information device. It is necessary to set QDs at the desired position for the fabrication of the quantum circuit. The methods to form the epitaxial QDs on the processed surface of the substrate have been proposed, but the generation of the nonradiative defects is unavoidable at the surface. QD is also attractive to the solar cell application. If the QDs are packed densely with long periodicity, the intermediate band will be created due to the overlap of the electron wave function among QDs. This artificial energy band will expand the light absorption wavelength, and will raise the photoelectric conversion efficiency up to 70%. Such epitaxial growth of QDs is, however, not easy. In this paper, we propose the usage of the colloidal QDs (C-QDs) in these applications. The emission wavelength of the C-QDs covers from visible to infrared. The positioning of the PbS C-QD was achieved using nano-scale holes processed by the scanning probe microscope (SPM) lithography of Si substrate. The SPM oxidation lines were used as a negative etching mask to form the holes of the depth same as the C-QD diameter. We also report that the three-dimensional long-periodic ordering of the C-QDs is attainable by depositing C-QDs into the pyramidal holes processed by the anisotropic etching of Si substrate. Microscope observations and optical evaluations suggested the creation of the intermediate band after the slow sedimentation of C-QDs into the holes.

Speaker
Biography:

Dominique Ausserre has completed his Ph.D. in 1985 from College de France, Paris. He joined the CNRS in 1986 and was a visiting scientist in IBM Almaden in 1987. He started a new lab in Institut Curie in 1988, and moved to Universite du Mans in 1991. He is director of research in CNRS since 1993. As the main inventor of the SEEC technique, he launched the start-up Nanoraptor in 2001. He has published more than 60 papers in reputed journals and filled about 15 patents, covering from instrumental optics to the physics of surfaces, complex fluids and polymers.

Abstract:

Using an anti-reflecting layer as supporting plate for imaging an ultrathin film in reflected light with better contrast is a powerful trick. This contrast is defined as the ratio of the difference and the sum of the object and background intensities. Thus, in principles, its value is one when the background reflectance is turned off. For homogeneous, isotropic and purely dielectric materials, single AR layers are defined by the two famous conditions n12=n0n2 and e1=λ/4n1 ruling respectively the refractive index and the thickness of the layer. Among other applications, such AR-layers may be used in order to probe ligand binding on surface grafted receptors. Then, the AR layer must be positioned between the solid support and the ligand solution, which refractive index is close to that of water. With a glass support for instance, the index condition imposes that the layer index is about 1.27. It does not correspond to any homogeneous material. It is therefore difficult to realize. Here we will present a new family of anti-reflecting layers which are particularly suited for biophotonic applications. They were obtained by a theoretical approach that we will expose. Their number is infinite. We will discuss their performances, their practical use for real time high contrast imaging in ligand-receptor experiments, and their manufacturing. At least, we hope that we will be able to present first experimental results.

Speaker
Biography:

Chih-Chun Chien obtained his Ph.D. in theoretical physics from the University of Chicago in 2009 and he is currently a distinguished J. R. Oppenheimer fellow in the Theoretical Division of Los Alamos National Laboratory. In addition to being an expert on theoretical atomic and molecular physics, he is part of a joint team (with K. A. Kirill, M. Zwolak, and Y. Dubi) working on designing and understanding the fundamentals of nano-scale thermal devices using biomaterials. He has published more than 40 papers in reputed journals.

Abstract:

By clamping a piece of DNA in between two metallic leads with slightly different temperatures, a nano-scale thermal junction can be realized using this “molecule of life”. DNA has a well-defined structural transition-the denaturation of its doublestranded form into two single strands that strongly affects its thermal transport properties. We show that, according to a widely implemented model for DNA denaturation, one can engineer DNA ‘heattronic’ devices that have a rapidly increasing thermal conductance over a narrow temperature range across the denaturation transition (around 80 ºC). The origin of this rapid increase of conductance, or ‘switching’, is the softening of the lattice and suppression of nonlinear effects as the temperature crosses the transition temperature and DNA denatures. Most importantly, we demonstrate that DNA nano-junctions have a broad range of thermal tunability by varying the sequence and length, and exploiting the underlying nonlinear behavior. We discuss the role of disorder in the base sequence, as well as the relation to genomic DNA. These results set the basis for developing thermal devices out of materials with nonlinear structural dynamics, as well as understanding the underlying mechanisms of DNA denaturation.

Break: Coffee Break 11:00-11:15 @ Bora Foyer

Lily Zu

Sympatec Inc. New Jersey, USA

Title: Effects of dilution on particle size measurement in dynamic light scattering

Time : 11:15-11:35

Speaker
Biography:

Lily Zu is the manager of nanoparticle division for Sympatec GmbH, and a member of the ISO committee for particle characterization. She has 22 years of experience in dynamic and static laser light scattering as well as sedimentation instrumentation design. She specializes in physical characterization of nanoparticles and macromolecules, including submicron particle size and distribution; electrophoretic mobility and phase analysis on zeta potential and size exclusion chromatography on molecular weight analysis using multi-angle light scattering. She is the inventor of the Optical Ball Lens Light Scattering Apparatus and Method.

Abstract:

The purpose of this paper is to articulate the effects of sample dilutionin particle size measurement using DLS technology, and how these effects may be minimized by using Photon Cross Correlation Spectroscopy (PCCS). Dynamic Light Scattering (DLS) is a non-invasive, fast and well established technique for characterizing submicron particle size and distribution. Generally, it requires significant sample dilution in order to achieve a correct result by avoiding multiple scattering phenomena. Sample dilution may change the chemical environment of the suspended particles in the sample. As a result, the measured size and distribution may deviate from its original value. PCCS is a subset of DLS, extending the range of sample concentrations that can be measured with DLS up to 106. A set of measurements for a series diluted NIST traceable monodispersed polystyrene latex nanoparticles gives comparative results for using PCCS vs PCS. It enables the clarification and verification of concentration dependency in particle size measurements and eliminates many of the assumptions in DLS measurements which are inherent with sample dilutionsthat may lead to skewed conclusions in a real application. Graph1 shows two repetitive PCCS measurements give a correct peak diameter of 101nm (green and blue curve), and PCS measurements give an artificially smaller peak diameter of 55nm (red and purple curve) in the concentration level.

Speaker
Biography:

Tamara Floyd-Smith completed her B.S. degree in chemical engineering at Tuskegee University in 1996 and her M.S. and Ph.D. degrees in chemical engineering at the Massachusetts Institute of Technology in 1998 and 2001 respectively. She is currently Professor of Chemical Engineering, 3M Scholar and Adjunct Professor of Materials Science and Engineering at Tuskegee University.

Abstract:

A carbon nanofiber array (CNF) sensor with electrochemical detection is proposed for the detection of both glucose and interleukin 6 (IL-6), an important biomarker in immune response. The CNFs are vertically aligned with a range in diameter from 25 to 100 nm and a range in height from hundreds of nanometers to one micrometer. In this study, the CNF array is capped with polydimethylsiloxane (PDMS) microchannels that allow confined flow over the array. Prior to modifying the carbon nanofibers for biomarker detection, the flow characteristics of the system needed to be investigated. Initially, the flow characteristics of inactive CNF array sensors capped with PDMS microchannels approximately 300 μm in depth were studied. Flow rates as high as 10 ml/min were tested corresponding to pressures lower than 30 kPa revealing that the CNF array and shallow microchannels do not create a significant barrier to reagent flow. The experimental results obtained in this study were also compared to theoretical models to gain additional insight into the behavior of this system. After characterizing the fluid mechanics of capped CNF array sensors, the electrochemical characteristics of the system were investigated for the biomarkers of interest. The results of the fluid mechanics and electrochemistry studies will be discussed.

Speaker
Biography:

Iwan Moreels obtained his Ph.D. degree in applied physics at Ghent University (Belgium) in April 2009. His work consisted of the synthesis, processing and application of near-infrared PbS and PbSe colloidal quantum dots on a silicon photonics platform. Ph.D. studies were followed by post-doctoral research in optical spectroscopy at Ghent University and the IBM Zurich research lab (Switzerland). In Januari 2012 he joined the Istituto Italiano di Tecnologia (Italy), where he now is leading the Nanophotonics Lab. He has published 35 papers in peer-reviewed journals, including 2 review articles.

Abstract:

Colloidal CdSe/CdS quantum rods (Qrods) are a versatile nanomaterial. By growing a CdS rod-like shell around a spherical CdSe core, surface defect formation can be efficiently suppressed, yielding a high photoluminescence quantum efficiency routinely larger than 50%. Furthermore, the small valence band offset between CdSe and CdS allows further control over their optical properties due to electron delocalization into the shell, which modifies the electron-hole wave function overlap and hence the luminescence spectrum and decay rate. The stimulated emission (SE) of these nanocrystals can also be controlled in great detail. SE can be obtained from CdS bandedge states, CdSe core states, or even both simultaneously, by control the carrier dynamics with the core diameter and the rod length. Moreover, temperature-dependent measurements from 325 K down to 5 K have revealed that the discrete nature of the electronic states leads to a nearly constant SE threshold, paving the way for temperature-insensitive quantum dot lasers. A large CdS rod encompassing the CdSe core is also beneficial for enhancing the two-photon absorption (2PA). Investigating the 2PA spectrum in CdSe/CdS Qrods, we observed a strong blue shift of the 2PA transitions compared to the linear absorption (1PA) spectrum. Results are quantitatively explained by k.p calculations, which attribute the blue shift to different optical selection rules applying to 1PA and 2PA. Combining these data with the Qrod SE results, we could demonstrate low-threshold gain by pumping under the appropriate two-photon conditions.

  • Track 5: Nanodevices and Nanosensors (Session 2)
Location: Salon A
Speaker

Chair

Arno Ehresmann

the University of Kassel, Germany

Speaker

Co-Chair

Seyed Sadeghi

University of Alabama, USA

Session Introduction

Seyed Sadeghi

University of Alabama, USA

Title: Quantum nanosensors based on quantum dot-metallic nanoparticle systems

Time : 12:15-12:35

Speaker
Biography:

Seyed Sadeghi received his Ph.D. in Physics from the University of British Columbia in Canada. He held NSERC postdoctoral fellowship before joining industry. In 2007, he joined University of Alabama in Huntsville. His fields of research include nanomaterials, quantum sensors based on hybrid nanoparticle systems, coherent optics of nanoparticles, and photophysics and photochemistry of colloidal quantum dots. Currently he is serving as an editorial board member of Journal of Nanomedicine and Nanotechnology and Dataset Papers in Optics.

Abstract:

Conventional nanosensors are based on intrinsic resonances of metallic nanoparticles (localized surface plasmons) and/ or semiconductor quantum dots (excitons). In this report, we propose ultra-sensitive sensors based on fundamentally different concepts and principles. In these sensors the rules of quantum mechanics are used to detect ultra-small variations of the refractive index of the environment. These quantum nanosensors are based on hybrid systems consisting of metallic nanoparticles and quantum dots. Interaction of these systems with a laser field generates quantum coherence and coherent exciton-plasmon coupling. This allows us to convert minuscule changes in the environment, caused by biological molecules for example, into dramatic optical events detectable by conventional and simple electronic and optical means. These sensors are not based on excitons or plasmons as in conventional sensors, rather they utilize the way environment influences the dynamics of coherent exciton-plasmon coupling and the intrinsic resonances (plasmonic meta-resonances) of the hybrid quantum dotmetallic nanoparticle systems.

Break: Lunch Break 12:35-13:05 @ Coral AB
Speaker
Biography:

Arno Ehresmann has completed his Ph.D. in Experimental Atomic Physics at the age of 29 from The University of Kaiserslautern, Germany. Postdoctoral studies on molecular photoionization and dissociation followed at Tokyo Institute of Technology and a position as vice president R&D systems technology and project manager at Deutsche Babcock Turbo-Lufttechnik, (wind tunnel instrumentation and solar simulation systems). He is now Professor of Experimental Physics at The University of Kassel and Director of the Center for Interdisciplinary Science and Technology (CINSaT) with 28 individual groups working in the nano sciences. He has published more than 140 papers in peer-reviewed journals.

Abstract:

Artificial magnetic domain patterns can be fabricated in exchange biased bilayers and some other magnetic multilayer systems by light-ion bombardment induced magnetic patterning (keV He+ ion bombardment in combination with resist masks and an applied magnetic field during the bombardment). This technique enables a local modification of, e.g., the exchange bias field in magnitude and in direction. Remanently stable magnetic patterns (artificial domains) may be created without large changes in surface topography. These patterns allow also a tailoring of the associated magnetic strayfield landscapes due to tailored magnetic charges at domain walls. The fundamentals for fabricating such artificial domain patterns will be discussed. The corresponding stray fields may be dynamically changed by overlaid external macroscopic magnetic fields or by a controlled domain wall motion. The use of the associated static and dynamic magnetic field landscapes for positioning of molecules and for the controlled movement of superparamagnetic particles by moving domain walls will be shown and their possible application in a lab on a chip device will be discussed. Besides the application point of view experiments on fundamental aspects of particle transport on or close to surfaces will be presented.

Speaker
Biography:

Jonathan S Lloyd is a post-doctoral researcher in the Nanoelectronics Research Group within the Multidisciplinary Nanotechnology Centre in the College of Engineering. He completed his Ph.D. in physics in 2011 after gaining a 1st class honours master’s degree in physics both at Swansea University, UK. His Ph.D.. focused on optical characterisation of nanostructures and in particular nano-Raman spectroscopy. Since then his research interests have centred around the integration of nano-materials into sensors for biological and chemical sensing applications. Kar Seng Teng is a Senior Lecturer at Swansea University and he is the Head of the Nanoelectronics Research Group within the Multidisciplinary Nanotechnology Centre in the College of Engineering. His research interest is in the application of nanotechnology in electronic materials and devices, which have major impacts in healthcare, energy and information technologies. His current funded research projects include nanobiosensors for continuous monitoring of chronic diseases, nanoplasmonics for photovoltaic and fabrication of nanowires devices using printing technology.

Abstract:

Zinc oxide (ZnO) nanowires have found many potential applications, ranging from sensors to optoelectronics, due to its unique chemical, electrical, optical and piezoelectric properties. Furthermore, the biocompatibility and high isoelectric point of ZnO nanowire means that the nanomaterial is an excellent candidate for biosensing application. Here we discuss the development of glucose biosensor chip based on ZnO nanowires. The device can be used in the continuous monitoring of blood glucose that is of paramount importance in managing chronic disease, such as diabetes. In this talk, the use of flexographic printing technique and hydrothermal growth of nanowires that enable high-volume low-cost production of these devices will be presented. Such fabrication technique would significantly reduce the production cost of these devicesand hence rendering them commercially viable.

Speaker
Biography:

Mehrdad Irannejad is optical Materials scientist, specializing in plasmonic devices and laser host materials engineering based on glass, glasssemiconductor and glass-polymer composite materials. He obtained his Ph.D. (University of Leeds, UK in 2012) in Photonics Materials Science Engineering and Master’s degree (University of Leeds, UK, 2008) in Nanoelectronic and Photonic Components Engineering. He is currently Postdoctoral Research Fellow at Waterloo Institute for Nanotechnology (WIN) at University of Waterloo, ON, Canada. His research interests include engineering of plasmonic devices, graphene electronics, laser hosts, glass-semiconductor integration and thin film technology. He has membership of OSA, IEEE and IoP.

Abstract:

Transmission enhancement of light through nanoscale holes or slits arrays in noble metal films has been an active research area back to 1998 when extraordinary transmission phenomenon was observed by Ebbesen et. al. Due to limit of nanofabrication, the nano-hole array (NHA) patterned in a noble metal film always has a non-vertical sidewall profile. There are three main methods that have been employed to pattern NHAs in a noble metal (e.g. Au or Ag) film, all of which lead to a tapered profile. The most popular method is focused ion beam (FIB) milling of holes into the metal film. A more efficient method for EOT device fabrication is nanoimprint/electron beam lithography followed by a liftoff process. However, the profile is tapered due to the lateral deposition of the noble metal during evaporation. The third method involves the fabrication of free standing thin (i.e.100 nm) membrane having hole array pattern, followed by evaporation of noble metal on top of it which leads to a negative tapered profile (i.e. opening becomes smaller toward the top of the hole). In this talk the optical behavior of non-vertical profile of NHA at different tapered angle and geometrical parameters is investigated by showing the examples of numerical and experimental results of positive and negative NHA profiles. The optimum geometrical parameters such as structural period, tapered angle and hole radius are demonstrated for higher transmission peaks and narrow peak line width which leads to increase the EOT device sensitivity. The effects of varying the refractive index of supporting material of the NHA on the optical transmission spectra are also studied and the optimum substrate refractive index which produces higher transmission peak and narrow peak line width is also reported.

Speaker
Biography:

Shane A. Catledge received his Ph.D. in Materials Science from The University of Alabama at Birmingham (UAB) in 1999, where he continued postdoctoral studies. His research career has focused primarily on nano-biotechnology as it applies to development of nanostructured diamond coatings for orthopaedic/dental implants, electrospun composite scaffolds for tissue regeneration, and nanodiamond fluorescence in biosensing. He has more than 55 peer-reviewed publications in the period from 2003-2013, which includes 3 book chapters as 1st author.

Abstract:

Fluorescent nanodiamond offers a promising platform for many biological applications including imaging probes, drug delivery, and biosensing. This is due, in part, to the potential to incorporate photostable luminescent defect centers into nanoscale diamond crystals which are biologically compatible and easy to functionalize. We present the first demonstration of spatially controlled nanodiamonds with nitrogen-enhanced photoluminescence from silicon-vacancy (Si-V) defect centers incorporated during microwave-plasma chemical vapor deposition. The potential for further enhancement of Si-V emission from these nanodiamonds is demonstrated through controlled nitrogen doping by adding varying amounts of N2 in a H2+CH4 feedgas mixture. At low levels, isolated substitutional nitrogen in {100} growth sectors is believed to act as a donor to increase the population of optically active (Si-V)- at the expense of optically inactive Si-V defects, thus increasing the observed luminescence from this center. The direct placement and manipulation of nanodiamonds is done by scanning probe lithography (SPL) using “inked” cantilevers. We explore suitable nanodiamond inks, the mechanism of ink transport, and parameters such as humidity and dwell time that affect the SPL process. The precise control in spatial arrangement of these highly photostable particles and their strong emission in the far-red (c.a. 738 nm) lends them well for applications in targeted drug delivery, biosensing and imaging devices as well as single cell in vitro studies for very specific therapeutic dosing or release kinetics.

Speaker
Biography:

Nekane Guarrotxena is a Ph.D. from the University of Complutense, Madrid-Spain in 1994 and has been post-doctoral research at the Ecole Nationale Superieure d´Arts et Metiers, Paris-France (1994-1995) and the University of ScienceII, Montpellier-France (1995-1997). From 2008-2011, she was visiting professor in the Department of Chemistry, Biochemistry and Materials at University of California, Santa Barbara-USA and the CaSTL at University of California, Irvine-USA. She is currently Research Scientist at the Institute of Polymers Science and Technology, CSIC-Spain. Her research interest focuses on the synthesis and assembly of hybrid nanomaterials, nanoplasmonics, and their uses in nanobiotechnology applications (bioimaging, drug delivery, therapy and biosensing).

Abstract:

Metal nanostructures strongly increase Raman signal intensities, making surface-enhanced Raman spectroscopy (SERS) a powerful analytical technique for ultrasensitive chemical and biochemical analysis. A key feature is that collective and resonant excitation (surface plasmon resonance) of the free electrons in metal nanostructures can enhance the electromagnetic fields near the particle surface, large enough for single molecule detection. This enhancement effect is exceptionally strong at the interstitial site between plasmon-coupled metal nanoparticles, making dimer-like metal (Au, Ag) nanoparticles or small aggregates promising SERS active nanostructures for sensory applications. A current challenge in designing these SERS hotspots is to maximize their uniformity, reproducibility, stability and intensity. In this sense, a rational control of agglomeration and ligand exchange of linker-mediated nanoassembly is relevant for effective exploitation of structure-dependent material properties in sensing applications. While our recent work has shown important improvements in SERS nanostructures sensitivity (SERSbased sensors with fM protein detection level) by properly managing surface properties on AgNP assemblies, the current nanofabrication methods are still far from ideal in achieving these controls. An alternative to non-ideal NPs assembly would be an effective postsynthetic purification method for collecting efficient SERS structure of linked dimers from NP assemblies. So, given that interparticle junctions (hotspots) produce the strongest SERS signals, this communication reports a post-synthetic strategy which leads to effective enrichment of SERS active Ag dimer-assemblies with higher SERS intensities for novel applications, such as optical sensors.

Georg Lefkidis

University of Kaiserslautern, Germany

Title: The quest for logic functionalization of magnetic nanoclusters

Time : 14:45-15:05

Speaker
Biography:

Georg Lefkidis studied Chemistry at the Aristotle University of Thessaloniki, Greece, where he also got his Ph.D. in the Laboratory of Applied Quantum Chemistry in 2002. In 2003 he joined the Physics Department of the University of Kaiserslautern, Germany, first as a postdoctoral fellow and, since 2007, as a tenured Senior Researcher/Lecturer. He has published more than 35 peer reviewed articles and serves as referee for several journals. His main research interests include second harmonic generation, ultrafast (magneto-) optics, laser induced dynamics and spintronics of nanoclusters, as well as the various degrees of freedom involved in the processes.

Abstract:

In this talk our quest for functional magnetic logic elements will be revised. Ever since the laser-induced ultrafast demagnetization of ferromagnetic materials was discovered, spintronics has become a main research field in the area of magnetism and optical control. Starting from one-magnetic-center over to two- and three-magnetic-center molecules, the necessary elementary mechanisms (spin flip and spin transfer) will be discussed to finally arrive at more complex functionalities such as actually constructing and preparing magnetic logic gates. With the help of high-level ab initio quantum chemistry the possible spin manipulation scenarios will be elucidated, followed by a discussion pertinent to the design of magnetic structures whose purpose is the coherent magneto-optical control. Emphasis will be given on the structural aspects of the most successful nanostructures as well as their electronic-level scheme. Along the way some derived rules-of-thumb and important physical aspects, like the conservation of total angular momentum, the spin and charge dynamics decoupling as well as the role of phonons and symmetry breaking will also be addressed.

Tetsuo Kodera

Tokyo Institute of Technology, Japan

Title: Silicon spin-based quantum information devices

Time : 15:05-15:25

Speaker
Biography:

Tetsuo Kodera has completed his doctorate in physics at the age of 27 years at the University of Tokyo. He was research associate at Institute for Nano Quantum Information Electronics, the University of Tokyo. He is an Assistant Professor at Quantum Nanoelectronics Research Center, Tokyo Institute of Technology. He has published more than 40 papers in reputed journals. He served as a Program Committee Member for the Meetings of Physical Society of Japan from 2010 to 2011. He was the recipient of the Presentation Award of the Japan Society of Applied Physics, and the Tokyo Tech Young Investigator Engineering Award.

Abstract:

Quantum information devices have been well studied because they are expected to have functionalities beyond existing information devices. A single electron spin in Si quantum dots (QDs) is one of the most promising candidates for implementing a quantum bit (qubit) as a unit of information in quantum computers. Long coherence time of electron spins is expected in Si QDs, because hyperfine coupling between electron spins and nuclear spins is small in Si. We develop a novel device structure of lithographically-defined Si QDs toward qubits. The Si QDs are fabricated using electron beam lithography, reactive ion etching, and oxidation, in a metal-oxide-semiconductor (MOS) structure on silicon-oninsulator (SOI) substrates. The advantage of our device is that well-defined confinement potential and small QDs (~20 nm in diameter) can be obtained. We studied both single QD and double QD devices. Charge detection of change in number of electron in QDs, one by one, has been successfully demonstrated in both devices. Few-electron regimes in QDs are also realized in both devices. Using the double QD devices, we succeed in observing spin-related tunneling phenomena. These achievements are the important steps for realizing qubits.

Biography:

Feng Long is Associate Professor at Renmin University of China. He received his Ph.D. from Tsinghua University in 2008 and completed postdoctoral studies from Department of Chemistry, Massachusetts Institute of Technology. He has extensive experience in conducting frontier research and developing tangible technologies such as nanostructure biosensors and evanescent wave optical biosensors. He also demonstrated excellence of track record in technology development, publication, patenting and technology transfer. He has published more than 35 papers in reputed journals and has been serving as an editorial board member of reputed journals.

Abstract:

A simple optofludics-based nanosensing system for sensitive and selective of trace environmental pollutants was successfully achieved by the effective integration of microfluidic platform with a QD-FRET-based bioassay. Nanoprobes were synthesized by conjugating carboxyl quantum dots with bisphenol A-BSA (BPA-BSA). Based on the indirect competitive immunoassay mode, the biosensing assay of BPA using the optofluidics-based nanosensing system in water samples featured good characteristics with its high sensitivity, rapidity, small sample volume, and minimum sample manipulation. BPA was quantified over the concentration range of 0.92 nM to 10.5 nM with a detection limit of 0.43 nM. Compared with traditional techniques, this system provides several advantages. First, by using assembled functional haptens that are conjugated to QD surfaces as recognition elements, the QD-hapten nanoprobe is more stable in complex environmental samples. Moreover, the binding properties of immobilized biomolecules are not compromised when the probes are prepared by immobilizing haptens onto the QD surface. Second, the structure of QD-protein-haptens prevents steric hindrance and maintains the high activity of the QD nanoprobe for its specific. Third, the FRET efficiency is higher because of the increased number of acceptor dyes bound to one QD surface, which results in the high sensitivity of the QD-FRET assay. Finally, an important feature of this optofluidic biosensing system is that only a small amount of sample solution (<10 μL) is required for analyses.

Break: Coffee Break 15:45-16:00 @ Bora Foyer
  • Track 4: Nanotechnology in Food and Agriculture
    Track 7: Nanotechnology in Energy Systems
    Track 8: Environment, Health and Safety Issues of Nanotechnology
Location: Fiji
Speaker

Chair

Bobby Kannan Mathan

James Cook University, Australia

Speaker

Co-Chair

Krishna Feron

CSIRO & University of Newcastle, Australia

Session Introduction

Bobby Kannan Mathan

James Cook University, Australia

Title: Degradation control of biodegradable biomaterials using nanotechnology

Time : 09:00-09:20

Speaker
Biography:

Bobby Kannan Mathan received his Ph.D. from the Indian Institute of Technology (IIT) Bombay in 2005. His Ph.D. dissertation was on developing a phenomenological model for the environment-assisted cracking mechanism in high strength aluminium alloys used in aircraft structures. He won the best Ph.D. Thesis Award from the National Association of Corrosion Engineers (NACE), India Section. After completing his Ph.D., he worked as a post-doctoral fellow at the Helmholtz Research Centre in Germany. His research focus was on understanding the localized corrosion behaviour of advanced magnesium alloys. In November 2006, he joined Monash University as a post-doctoral fellow, where he worked on magnesiumbased biodegradable biomaterials. In February 2009 he joined JCU as a Lecturer of Chemical Engineering. He is currently the Head of Chemical Engineering in the School of Engineering and Physical Sciences. He is the group leader of the Biomaterials and Engineering Materials (BEM) laboratory at JCU. His current research interests include electrochemical engineering, biomaterials, corrosion, wastewater treatment, environmentassisted cracking, polymer coatings and failure analysis of engineering materials. He has written four book chapters and published over 50 papers in journals and peer-reviewed conference proceedings.

Abstract:

In this ageing population, the use of implants for repair of fractured bone tissues has been increasing rapidly. Traditionally, implant materials such as stainless steel and titanium alloys are used for temporary mini-implant applications in orthopaedics and dental maxillofacial fixation. Due to the risk of toxic metallic ion release through corrosion and/or wear, these implants are removed surgically after the tissues have healed completely. However, it is well known that any surgical process poses risk to the patient. Biomaterials that support tissue regeneration and healing by material degradation and simultaneous implant replacement by the surrounding tissues can resolve these problems. Magnesium is a suitable material for biodegradable implant applications if its degradation rate is controlled. In fact, the biocompatibility and mechanical properties of magnesium are very attractive for such applications. A considerable amount of work, especially on conventional methods such as alloying and coating, has been done to control the high degradation rate of magnesium in body fluid. However, nanotechnology has proven to enhance the performance of magnesium-based alloys significantly. In this talk, the advancement made on magnesium-based biomaterials using nanotechnology for potential temporary mini-implant applications will be discussed.

Krishna Feron

CSIRO & University of Newcastle, Australia

Title: Nanoparticle organic solar cells

Time : 09:20-09:40

Speaker
Biography:

Krishna Feron obtained his B.Sc. in Applied Physics (Cum Laude) at Twente University in the Netherlands and has completed his Ph.D. at the age of 25 from the University of Newcastle in Australia. Subsequently he received a postdoctoral fellowship from the Australian Renewable Energy Agency to conduct research into the energy losses in organic cells. He has a joint appointment with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Centre for Organic Electronics at the University of Newcastle. He published several papers in the field of organic solar cells, including an invited review.

Abstract:

Organic solar cells show great potential as a cheap renewable energy technology. In the fabrication process of organic solar cells usually two photo-active components are dissolved in an organic solvent such as chloroform. This solution can be deposited using a variety of printing and coating techniques to obtain a thin film of photo-active material. Deposition processes using organic solvents, however, are undesirable as these pose health and environmental risks, especially in large-scale deposition approaches. In order to mitigate these risks, aqueous based organic semiconductor nanoparticles were prepared using a miniemulsion technique. The added advantage of using a nanoparticle based approach is the inherent control over domain size. The nano-structure of the photo-active materials is known to have a major impact on the photo-electron conversion efficiency and a domain size of the order of tens of nanometers is found to be optimal. In order to induce a favorable nano-structure, thermal treatments were employed. X-ray photo-electron spectroscopy (XPS) depth profiling measurements were used to determine the chemical composition throughout the organic solar cell. The results provided insight into what drives molecular diffusion of the photo-active constituents and they elucidated the effect of the nano-structure on device performance. Finally, the XPS measurements were used to identify an approach to easily increase device performance while mitigating the health, safety and environmental risks associated with organic solvents.

Kukutschova Jana

VSB Technical University Ostrava, Czech Republic

Title: Braking of automobiles: A potential source of nanoparticulate emissions

Time : 09:40-10:00

Biography:

Kukutschova Jana has completed his Ph.D. and postdoctoral studies from Faculty of Metallurgy and Materials Engineering at VSB-Technical University of Ostrava, Czech Republic. She is the Head of Department of Bionanotechnology at Nanotechnology Center of VSB, Technical University of Ostrava. She has published more than 20 papers in reputed journals and is a member of American Nano Society, Society of Automotive Engineers and Czech Chemical Society.

Abstract:

Considerable amounts of pollutants are generated by more than one billion registered vehicles worldwide. While the emissions related to exhaust gasses and tire wear were addressed extensively, the released brake wear debris and its impact were studied to a considerably lesser extent. Our previous work indicated that the released wear debris can have negative impact on environment. A characteristic automotive brake pad is a multicomponent composite typically formulated of more than 10 constituents. Manufacturers of brake pads worldwide use several thousand different raw materials, e.g. various metals and their compounds, carbon-based components and many others. This contribution addresses the character of wear debris released from a model friction material, used in a typical brake in Europe, USA and Asia. Brake samples were subjected to the standardized brake dynamometer test simulations and collected particles were further studied using a high resolution transmission electron microscopy with the EDX microanalysis. Our experiments demonstrated that airborne wear particles with sizes between 10 nm and 20 μm can be released into the air. Phase analysis revealed numerous compounds which were not present in the original brake material. Nano-sized Cu, Fe, and Sn oxides and carbon particles were confirmed in the released coarse, fine and ultrafine wear debris fractions. Moreover, nano-sized wear particles were observed to be released after a contact with water from the non-airborne wear particles which settle on road surfaces. These findings proved contribution of braking of automobiles to nanoparticulate air pollution which may potentially pose health risks in areas with heavy traffic.

Speaker
Biography:

Stephen Skinner is a Reader in Materials Chemistry in the Department of Materials at Imperial College London with research interests in new materials for energy generation/storage technologies. He is primarily interested in the development of materials for solid oxide fuel cells and in understanding their transport properties, utilizing a combination of diffraction and spectroscopic techniques. In-situ structural and electrical characterization of oxides and the determination of the oxygen transport kinetics are key areas of interest. He has published over 90 papers in this area and is currently associate editor of the Journal of Materials Chemistry A.

Abstract:

The need for high performance mixed conductors in a variety of electrochemical devices is well documented: from electrolysis to fuel cells, batteries, & permeation membranes. Many of these devices are also reliant on the exchange of species from the gas phase to the solid phase through an oxygen reduction reaction. However the understanding of these processes at the outermost surface is not well understood. Current models suggest that in many oxides it is the presence of transition metal species on the surface that facilitates the oxygen reduction reaction. Recently, with the advent of new surface sensitive techniques such as low energy ion scattering, we have been able to demonstrate that in perovskite and related materials the transition metal is not the terminating species on the surface, which has implications for development of models of oxygen reduction. In this work we have used model thin film systems to demonstrate these features.

Speaker
Biography:

Alireza Valanezhad received a Ph.D. in biomaterials from Kyushu University Japan. Began his career as a lecturer in Sahand University of Tabriz. He became Assistant Professor of Kyushu University Japan in 2011 and followed as a research staff of Chubu University Japan. His research interests are surface coating, modification, energy materials, nanotechnology and biomaterials.

Abstract:

It is important for electrodes for electrochemical reactions such as fuel cell or solar cells to show high total surface area, electrical conductivity and catalyst fixation ability on their surfaces. In the present study, pure Ti metal was soaked in 5 M NaOH aqueous solution at 60°C for 1 h, then in 0.5 mM HCl solution at 40°C for 3 h and heated at 600-1000°C in N2 gas for 1-12 h. The surface structural changes, especially about the effect of temperature and duration time of heat treatment on the incorporation of elements N, electrical conductivity were studied. After chemical and heat treatments, a porous nano network structure with high surface area mainly composed of Ti oxides such as anatase, Ti-oxynitride and Ti nitrides such as Ti2N with about 600 nm in thickness was formed on their surfaces. It is revealed by X-ray photoelectron spectroscopy analyses on elemental ratio and depth profile that the N was incorporated preferentially into the deep dense region below the network layer at low heat treatment temperature, but incorporated more and more into the network structure at top surface at higher temperature or for longer period. It was also revealed that their conductivities increased with increasing N incorporation amount and that the treated Ti metal can fix some redox catalyst on its surface and work electrochemically. Conclusively, the Ti electrode with high specific surface area, conductivity and catalyst fixation ability on its surface can be prepared by heat treatment in N2 atmosphere after alkali and acid treatments.

Hemali Rathnayake

Western Kentucky University, USA

Title: Innovative energy harvesting nanostructures for organic-based solar cells

Time : 10:40-11:00

Speaker
Biography:

Hemali Rathnayake obtained her Ph.D. under the supervision of Prof. Paul M. Lahti, UMass Amherst, Department of Chemistry in 2007. Just after she finished her Ph.D. thesis defense, she joined Emrick’s Research group at Polymer Science & Engineering, UMass Amherst. During her Postdoctoral time period (December 2006 to June 2009), she has worked on various projects on developing new polymer-nanocomposites and hybrid nanostructures. In July 2009, she joined the Chemistry department at WKU as an Assistant Professor.

Abstract:

Linear conjugated polymers (LCPs) exhibit very complex self-assembly behavior due to their structural flexibility, longer chain length, and wide molecular weight distribution. It is essential to develop LCPs having both improved optoelectronic and organizable self-assembly properties. To improve the progress of organic-based devices, synthetic methods need to be developed to make well-defined three-dimensional structures with a controlled size and shape in conjunction with delicately organized selfassembly properties. Here, a series of donor- and acceptor-functionalized nanostructures having both improved optoelectronic and well defined self-assembly properties for low-cost, high efficiency, and flexible solar cells will be disussed. This work will contribute to the fundamental knowledge in this discipline by developing better synthetic methodologies, designing novel hybrid nanostructures, and assembling them in organic polymer matrices. Incorporating linear conjugated polymers to selfguidable three-dimensional structures should avoid the formation of micrometer-sized phase segregated domains, which leads to incomplete exciton dissociation. Improvements inefficiency will be realized by obtaining nanoscale phase separation using these hybrid materials.

Break: Coffee Break 11:00-11:15 @ Bora Foyer
Speaker
Biography:

Tetsuji Okuda is Assistant Professor at Hiroshima University, Japan. His research work focuses on the remediation of contaminated soil. His other interests’ are waste and water treatment by chemical and physical methods in where he published several papers in international journals and presented at several international conferences.

Abstract:

Soil pollution by persistent organic pollutants (POPs) and heavy metals, especially lead, arsenic, cadmium, chromium and fluorine are major environmental concern in Japan, especially after the Soil Contamination Countermeasures Law enforcement in 2003. In addition, in Japan, the major concern on the radioactive cesium deposition and its soil contamination due to the emission from the Fukushima Daiichi Nuclear Power Plant showed up after a massive quake on March 11, 2011. Hence, its remediation is recognized to be one of the most difficult problems to be solved by taking advantage of suitable technologies. Recently, the impacts of nanotechnology are increasingly evident in the field of environmental studies and treatment. In present study, we focused synthesis and application of nanosize metallic calcium and iron dispersion for detoxification of multi-pollutants containing radioactive cesium, heavy metals and POPs in contaminated soil. Results show that the dechlorination of POPs was about 97, 59, 60 and 29% in 0, 1, 4.4 and 9.6% soil moisture content, respectively. While, about 95-99% heavy metals immobilization was achieved by mechanochemical treatment of soil with nano-metallic-calcium and phosphoric acid, which improved to make thin cover on soil surface by developing low soluble calcium apatite. In addition, the high concentration of cesium and heavy metals containing soil fraction, was also separated by magnetic separation by the addition of iron powder after treatment with nano-metallic-calcium. With iron fraction, high concentration of heavy metals was successfully separated about 36-45%, with high condensed heavy metal concentration about 85-95%by the magnetic separation of small particle fractions with high specific surface area, where both pollutants and iron accumulated. Similarly, about 30 wt% magnetic and 70 wt% non-magnetic fraction soils were separated, and its condensed cesium concentration was about 80% and 20%, respectively. Furthermore, we revealed two major effects, i.e. the reduction of chlorine from POPs (chemical effect) and coating and blocking of soil surface (physical effect) as the remediation mechanisms.

Speaker
Biography:

Srinivasa Reddy Mallampati is a Postdoctoral Research Fellow in Department of Environmental Sciences at Prefectural University of Hiroshima, Japan. His research work focused on the “synthesis and application of nano-size metallic calcium and iron dispersion for detoxification of multipollutants containing radioactive cesium, heavy metals and POPs in contaminated soil”. He has been awarded with JSPS Postdoctoral Research Fellowship during 2007-2009. He did his Ph.D. work at CSMCRI, one of the National Laboratories of India (CSIR). He is the author of more than 25 papers in reputed journals. He has also presented papers at several international conferences and they have been enthusiastically received. Recently, he got Young Scientist Award from American Academy of Sciences, Houston, TX. USA.

Abstract:

In Japan, the major concern on the radioactive cesium (134Cs and 137Cs) deposition and its contamination due to the emission from the Fukushima Daiichi nuclear power plant showed up after a massive quake on March 11, 2011. By the end of March 2012, ash containing 100,000 to 140,000 becquerels per kilogram (Bq kg−1) of (134Csand 137Cs) was recorded. High levels of 134Cs and 137Cs are also present in incineration ash from normal garbage. The volume of radioactive cesium contaminated ash in the northern part of Japan is growing at 360 t/d. During and after 30 years it takes for 137Cs to decay by half, each time it rains, 134Cs and 137Cs deposited will be washed down to where people live. For the entire ecosystem, 134Cs and 137Cs are being accumulated in the environment. Temporary disposal sites for incinerated ash containing 134Cs and 137Cs are rapidly filling up. No alternative landfills are available. Therefore, the134Cs and 137Cs removal and immobilization in contaminated fly ash are recognized as important problems to be solved using suitable technologies. Recently the impacts of nanotechnology are increasingly evident in the field of environmental studies and treatment. Treatment and remediation has seemingly experienced the most growth in recent years. In terms of site remediation, the development and deployment of nanotechnology for contaminant destruction has already taken place. Present study, first time we conducted to determine the capability of nanometallic Ca/CaO methanol suspension to extract and immobilize 134Cs and 137Cs in contaminated fly ash. Simultaneous high cesium extraction and immobilization were achieved using methanol/nanometallic Ca/ CaO methanol suspension in a synthetically prepared stable cesium (133Cs) contaminated fly ash sample. For actual radioactive cesium contaminated fly ash samples obtained for Fukushima, Japan, after with nanometallic Ca/CaO methanol suspension extraction, total 134Cs and 137Cs concentrations in fly ash was much lower, 3,583 Bq kg−1 than the Japanese Ministry of the environment regulatory limit of 8,000 Bq kg−1, which allows the ash to be buried in landfills. Scanning electron microscopy with electron dispersive spectroscopy (SEM-EDS) revealed that the mass percent of 133Cs detectable on the fly ash surface was decreased 100% after nanometallic Ca/CaO methanol suspension extraction, perhaps because of its agglomeration with the Ca/ CaO hydration product matrix. The most probable mechanisms for enhanced cesium removal and immobilization capacity with nanometallic Ca/CaO methanol suspension extraction are portrayed schematically in (Fig. 1). These results highlight the potential of nanometallic Ca/CaO methanol suspension as a unique amendment for remediation of 134Cs and 137Cs in contaminated fly ash.

Speaker
Biography:

Malavath Thavarya is currently working as professor in JNT University, India. His research interests are mainly nanotechnology

Abstract:

This paper presents design and performance analysis of acrylic coated small scale passive solar air heater, which can be easily and economically fabricated from recycled aluminium drink cans. Aluminium cans are used as absorbing medium. In the experimental study, a solar air heater with the length of 1.2 m, width 0.6 m was fabricated and performance study was carried out in 8 different cases, without acrylic coating and with black coating of absorbing medium with natural air inlet and forced air inlet at horizontal and inclined with tilt angle of 35º of air heater. The experimental results show that coating and inclination and mass flow rate affect the efficiency of solar air heater. The efficiency is more at inclination than at horizontal.

Nitai Debnath

Amity University Haryana, India

Title: Nanoparticles as novel insecticidal agent for crop protection

Time : 12:15-12:35

Speaker
Biography:

Nitai Debnath Worked as a part-time lecturer of Zoology in Bejoy Narayan College, Itachuna, Hooghly, West Bengal (A Govt. aided College affiliated to University of Burdwan, approved by University Grant Commission, Govt. of India). Worked in a multi-institutional research project on computational biology of immune network (together with Indian Statistical Institute, Kolkata; All India Institute of Medical Sciences, New Delhi; Chittaranjan National Cancer Institute, Kolkata; B.Borooah Cancer Research Institute, Guwahati) under the guidance of Prof. D. Dutta Majumder (Professor Emeritus of CSIR and ISI, FNASc, FIETE, FCSI, FNAE, FNA, FIAPR, FTWAS).Worked as trainee molecular biologist, in the laboratory of Dr. Arunava Goswami of the Biological Sciences Division of the Indian Statistical Institute on `biotechnology and molecular biology of effects of plant derived biomolecules on insects and higher organisms.’ Incidentally, Dr. Goswami worked with Prof. Linda Buck of Harvard University, winner of Nobel Prize 2004. I received extensive advanced training under him for doing proteomics and genomics along with standard molecular biology applications in the research project mentioned above.

Abstract:

Break: Lunch Break 12:35-13:05 @ Coral AB
  • Track 6: Nano-electronics
Location: Fiji

Chair

Alexander Eisfeld

Max-Planck-Institute for the Physics of Complex Systems, Germany

Speaker

Co-Chair

Peter A. Sloan

University of Bath, UK

Session Introduction

Toshio Hayashi

Nagoya University, Japan

Title: Recent development of Si chemical dry etching technologies

Time : 13:05-13:25

Speaker
Biography:

Toshio Hayashi has completed his Ph.D. for molecular orbital calculations of organic compounds on 1976 from Tohoku University. He was the senior research manager of ULVAC Inc., and joined with Nagoya University on 2006. He has published more than 42 papers in reputed journals and patented over 80, and served as a reviewer of Jpn. J. Appl. Phys and an editorial committee member of J. Vac. Soc. Jpn. and serving as a program committee member of DPS-2013 symposium.

Abstract:

Chemical dry etching in wafer processing was first developed by Horiike and Shibagaki (1976) using CF4/O2 downflow plasma for poly-Si etching, to prevent the degradation of the electrical properties of ICs due to the bombardment of charged particles. Thereafter, many researchers developed and reported various chemical dry etching methods. Advanced Si chemical dry etching technology was developed by Tajima and Takahashi (2010), using N2 downflow plasma and NF3 flowing to the downflow plasma area. The etchant production mechanism for this technology was explained by us. In these technologies, the plasma source is necessary to produce the etchants (F for Si etching and HF+NH3 for SiO2 etching). Recently, a novel Si chemical dry etching technology was developed by us without plasma source, in which F atoms generated in F2 + NO → F + FNO; reaction is used for Si etching. The etch rate at room temperature is more than 5 μm/min and is dependent on the flow rate and on the distance between the gas mixing point and the wafer position. Increasing the substrate temperature, the minimum etch rate was obtained at 60ºC. Over this temperature, the etch rate increased again with increase of the substrate temperature. In the lower temperature region, the chemisorbed layer may be formed and the chemical reaction may be enhanced in this condensed layer. Increasing the temperature, this chemisorbed layer disappears around 60ºC. Over this temperature, the surface reaction mainly takes place according to Arrhenius equation.

Alexander Eisfeld

Max-Planck-Institute for the Physics of Complex Systems, Germany

Title: Rotational motion driven by single electron tunneling

Time : 13:25-13:45

Biography:

Alexander Eisfeld has obtained his Ph.D. from the University of Freiburg and is now leading the research group Quantum Aggregates at the Max- Planck-Institute for the Physics of Complex Systems.

Abstract:

Much effort has been devoted to investigate the coupling of electrical and mechanical degrees of freedom on the nanometer scale in order to design novel electronic devices. An example is the nano-mechanical single-electron transistor (NEMSET), where electrons are transported from a source to a drain electrode via a movable nano-object which can be occupied by exactly one electron. The charged object experiences a force caused by the electric field between source and drain. The interplay of vibrational motion of the particle and the strong distance dependence of tunneling (which is responsible for charging/decharging) gives rise to mechanically assisted electron transport, called electron shuttling. Recently we investigated a nano-rotor based on the same mechanism as the electron shuttle described above. This rotor exhibits novel effects, which could be used for various applications, like sensors or charge pumps. The coupling of mechanical motion and tunneling leads to the self-excitation of oscillatory motion and large bias voltage to rotational motion even in the presence of damping. The frequency of oscillation/rotation depends on the ratio of the driving force and the friction. For small ratios the rotors oscillates and the current through the device decreases with increasing bias voltage (negative differential conductance). For larger bias full rotations appear with increasing frequency. Thus one may realize a nanoscale motor driven by static voltage. We will also present new results how the direction of rotation depends on the asymmetry of the rotor.

Speaker
Biography:

Bohdan Schatschneider completed both his B.S. (1998) and M.S. (2001) in chemistry at Florida Atlantic University. He went on to complete his Ph.D. (2008) at the University of California, Riverside. He is now an Assistant Professor of Chemistry at Penn State University, Fayette where he has published 11 papers in reputed journals and has presented his work 5 times at conference events.

Abstract:

The quest for cheap, light, flexible materials for use in electronic applications has resulted in the exploration of soft organic materials as possible candidates, and several polycyclic aromatic hydrocarbons (PAH) have been shown to be versatile (semi) conductors. Dispersion corrected density functional theory is used to explore all crystalline PAHs existing within the Cambridge Crystal Structure Database (CSD) from both structural and electronic standpoints. Excellent agreement is achieved between the experimental and calculated structures, and electronic properties. It was found that addition of a 1.46 eV constant to the Kohn-Sham HOMO-LUMO band gap provided excellent agreement with experiment. Hirshfeld surface analysis revealed that there is a direct relationship between the density of the structures and the relative fractions of C...C intermolecular contacts. Relationships between the contact fractions and the band gap are established. An inverse relationship was found to exist between the density and band gap in these organic molecular crystals (OMC), where the beta and gamma motifs provide the smallest band gaps. Limits in the maximum band gaps of stable PAH crystals containing only aromatic carbon and hydrogen are established as a function of C...C close contact fractions, intermolecular cohesive energy, and density. A 2.0 eV band gap minima was also established for all stable PAH crystals.

Norifusa Satoh

National Institute for Materials Science, Japan

Title: Molecular technology for atomic-level precise artificial atom

Time : 14:05-14:25

Speaker
Biography:

Norifusa Satoh received his Ph.D. from Keio University with honors in 2006. After serving as a postdoctoral researcher and an Assistant Professor at Keio University, he moved to National Institute for Materials Science (NIMS) as a permanent staff researcher in 2009. During 2011-2013, he was a visiting scientist at Harvard University. Through his wide range of experiences manipulating atoms and electrons in molecular chemistry, he aims to apply the fundamental concepts to oxide-based materials and electronics.

Abstract:

As the future nanotechnology, atomic-level manufacturing is vital in various research fields including the next generation electronics and energy-related devices. Simultaneously, we need to consider our sustainable development: The limitation of elemental resources, impacts on the environment, material safety, and stability. Herein, we functionalize oxides based on a concept of artificial atom through atomic-level control of the structure because oxygen is the most abundant element existing as oxides on the earth. Additionally, artificial atom has attracted much attention to create artificial materials unlimited by the atomic properties and to develop single-electron electronics based on Coulomb blockade. To obtain an ideal artificial atom at room temperature (RT), the tiny dots need to be less than 2 nm in size so that the charging energy of each single electron exceeds the thermal energy at RT. Besides, reorganization of the surroundings dominates electron transfer in molecular scale as described by Marcus theory, which is totally different with electron tunneling adopted in nano scale. Therefore, we first established a method to deposit molecular-scale oxide dots on substrates based on the number of metal ions contained in super-molecular assembling precursor; oxide is beneficial to obtain atomic-level precise structures due to the strong binding energy of ionic covalent bond. Next, we seamlessly covered the surroundings with atomic layer deposition oxides. In the molecular technologies, the chemical design of precursors and chemoselective multistep processes like multistep total synthesis in organic chemistry make it possible to oxide-based complex structures with atomic-level precision.

Speaker
Biography:

Peter A. Sloan joined the University of Bath in 2010 as a Lecturer in Experimental Physics. He was awarded a Ph.D. in Physics from the University of Birmingham in 2004. He has worked as a Royal Society research fellow with the Nobel Prize winning chemist Prof. John Polanyi at the University of Toronto, and as a Research Officer at Birmingham. His research interests lie at the boundary of physics and chemistry and explore the possibilities of controlling and manipulating individual atoms and molecules.

Abstract:

The tip of a scanning tunnelling microscope can manipulate individual atoms and molecules on a surface with atomic precision. Such atomic manipulation is the cutting edge of bottom-up nanoscience. Conventional atomic manipulation occurs exclusively in the tunnel junction (i.e., local to the tip) and has revolutionized nanoscience by the painstaking one-atomat- a-time construction of bespoke nanostructures for proof-of-principle demonstrations. However, the serial one-at-a-time nature of conventional atomic manipulation makes the construction of extended structures impracticable. Here report on the system of chlorobenzene on the Si(111)-7x7 surface and the STM tunnel current induced chlorobenzene desorption will be reported. As the figure shows, charge injected from the STM tip (at ‘X’) induced molecular desorption of chlorobenzene molecules (dark-spots) from the Si (111)7x7 surface generating relatively clean (~10 nm radius) areas of crystal surrounding the injection site. The manipulation is therefore nonlocal to the tip, occurring many nanometres distant. This mode of manipulation offers the tantalizing possibility of manipulation many molecules in parallel all with (possibly) atomic resolution. The talk will be concluded with some thoughts on some possible future direction for nonlocal manipulation, what it can tell us about the manipulation process, what it may reveal about nanoscale transport properties.

Speaker
Biography:

Megumi Akai-Kasaya obtained her Ph.D. in Physical Chemistry from Osaka University in 1997 on the topic of STM imaging mechanisms of organic molecules combined with computational simulations. She is currently an Assistant Professor of Division of Precision Science & Technology at Graduate School of Engineering Osaka University. From 2005-2009, she joined the PRESTO program of “Structure Control and Function” at Japan Science and Technology agency. Her scientific interests include self-assembly in non-equilibrium/dynamic systems, carrier transport in nanostructured soft materials and development of new functional device utilizing their nanoscale physical properties.

Abstract:

Interface between organic semiconductor and dielectric is an important key requirement to survey the mechanism of carrier transport, because only few molecular layers at the interface govern the intrinsic feature in organic field effect transistors. Nevertheless, fundamental questions in terms of charge transport mechanisms in such low-dimensional organic layer are still controversial. A nonlinear conduction, which depends on both temperature and lateral voltage, is an intriguing and fundamental physical property of them. Recently, power law behaviors of current-voltage characteristics have been reported in low dimensional systems. In some cases, the apparent of power law has been related by dissipative tunneling processes, such as Coulomb blockade. The Coulomb blockade effect was rarely suggested for origin of the nonlinear conduction in condensed organic conductors. We investigated a charge transport through two-dimensional conjugated polymer monolayer. The observed features, lateral voltage threshold decrease as temperature increase and the subsequent current increase according a power law, coincide in an expression for electrical conductivity in two-dimensional Coulomb blockade array system. We propose a carrier transport model composed of isotropic extend state of charged carrier in the monolayer, which has been calculated by a density functional theory calculation. Quantitatively evaluated capacitances of the charged states are adequate to explain the experimental results, though they are quite small as compared with that of metal particles. We suggest that Coulomb blockade effect should be taken into account as one factor in origin of nonlinear charge transport, which is frequently observed in organic materials.

Wen Bin Jian

National Chiao Tung University, Taiwan

Title: Semiconductor nanowire field-effect transistors gated by metal nanowires

Time : 15:05-15:25

Speaker
Biography:

Wen-Bin Jian obtained his Ph.D. in Physics from National Taiwan University in 2002. He worked as a postdoctoral researcher in University of New Orleans (Advanced Materials Research Institute) in 2003 and, later on, as an Assistant Professor in National Chung Hsing University. In 2004, he joined Department of Electrophysics, National Chiao Tung University. He got promoted to be a full Professor in 2011. His current research interest is nanoscience. He was invited for more than 12 times of oral presentations and he gave more than 10 times of contributed talks in international conferences. He has published more than 40 peer-reviewed papers in international journals, including Nano Lett., Phys. Rev. Lett., J. Am. Chem. Soc., and ACS Nano.

Abstract:

Gating control of semiconductor nanowires, like ZnO nanowires, have been demonstrated for a decade. The semiconductor nanowire field-effect transistor (FET) is commonly gated by either a back gate or a top gate electrode. The back gate operation requires a high voltage to generate a high electric field whereas the top gate technique needs the insertion of a thin insulating layer. Here we propose to employ a metal nanowire as a top gating finger. Due to the ultra-small cross-sectional area and the Schottky contact between the metal and the semiconductor nanowires, a low gating voltage is enough to generate a high electric field. Moreover, the contact resistance is high thus the gating operation is realized without any insulating layers. The zinc tin oxides (ZTO) nanowire was selected and a gold (Au) nanowire was attached on top as a gating finger. Conducting wires with four ohmic contacts on the ZTO nanowire and one ohmic contact on the Au nanowire were patterned by standard electron-beam lithography so as to make nanowire-gated FET devices. Four probe measurements on ZTO nanowires revealed intrinsic electron transport properties which were well described by the model of Mott’s three-dimensional variable range hopping. Electrical characterization with one probe on ZTO and the other on Au nanowire exhibits a Schottky and nano Schottky contact features at high and low temperatures, respectively. The nanowire gating with a low voltage of ±1 V demonstrates much higher efficiencies in comparison with back gating operation. Furthermore, the device can be operated by both finger and back gates to materialize a logical operation of the tri-state buffer.

Break: Coffee Break 15:25-15:40 @ Bora Foyer