Venue: Room 806, T5 building, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi

Time: 4h pm, Friday, 20^th April 2018

Speaker: Prof. Sung Hun Jin

Affiliation: Department of Electronic Engineering, Incheon National University, Incheon, South Korea

Abstract:

For nearly five decades, scientists and engineers have managed to drive revolutionary technology by shrinking silicon transistors, the building blocks for all computing. Now transistors are approaching fundamental roadblocks that mean the devices cannot still be fashioned from silicon if they are to become any smaller. Researchers are therefore looking for materials to replace silicon. Among many candidates, one of the most promising options is single wall carbon nanotube (SWNT) based transistors because their ability to operate at low voltages (saving chip power) and their exceptional performance in devices in which the length of the current-carrying CNT channel is less than 10 nanometers. However, the road to producing transistors from single-walled carbon nanotubes (SWNTs) has been hedged about the difficulties of purifying and controllably positioning these tiny molecular cylinders, which have a diameter of about 1 nanometer.

Here we report one of the most fascinating methods for obtaining arrays of highly purified semiconducting CNTs with its process scalability and compatibility with the state of the art Si technology. Nanoscale thermocapillary flows in thin-film organic coatings followed by reactive ion etching serve as highly efficient means for selectively removing metallic carbon nanotubes from electronically heterogeneous aligned arrays grown on quartz substrates. The low temperatures and unusual physics associated with this process enable robust, scalable operation, with clear potential for practical use. We carry out detailed experimental and theoretical studies to reveal all of the essential attributes of the underlying thermo physical phenomena. In this talk, from the perspective of electrical engineering, the recent amazing progress particularly since 2012 on carbon nanotube electronics toward mass production and its future will be also introduced and discussed with a concise manner. In addition, recent progress in the fields of transient electronics based on SWNT and a-IGZO FETs for hardware-secure systems or clandestine electronic devices for military applications as well as many environmentally friendly sensors with minimized waste streams are also introduced. Finally, the latest activities in the field of transparent conducting film (TCF) are summarized and their opportunity by means of SWNTs films for the applications of flexible electronics will be also discussed casually.

Biography:

Sung Hun Jin obtained the M.S. and Ph. D degrees in electrical engineering from Seoul National University (SNU), Seoul, Korea, in 2000 and 2006, respectively. During that time, he researched on micro display of one-chip FED and OLEDs, organic thin film transistors and its device physics on scaling down effects. After getting Ph. D, he worked as a senior engineer in Samsung electronics for about 4 years. As a project manager, he researched on the development of Smart TEGs, advanced Samsung TFT model, model parameter extraction, and TCAD simulation for next generation TFTs in the panel design and computer aided engineering (CAE) group.

For nano and flexible electronics, he joined in in Prof. John A. Rogers’ group at University of Illinois at Urbana-Champaign (UIUC) since Nov. 2009. His main research accomplishments on purification of aligned carbon nanotubes outcome was published in Nature nanotech. 8, 347 (2013). After he served as BK assistant professor in Seoul National University in 2013, he joined in Incheon National University in 2014. His current research interests include hybrid multi-scale materials (SWNTs, TMDCs, Si, et) and devices for smart flexible system. Furthermore, he has extended his research scope toward neuromorphic devices, bio-and-chemical sensors, transient electronics, and supercapacitors as one of energy storage devices, for the bio-, eco-friendly-, security related applications.

Venue: 806, T5 building, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi

Time: 2h pm, Monday, 26th March 2018

Speaker: Dr. Isabelle Kleiner

Affiliation: Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS et Universités Paris Est-UPEC et Paris Diderot,  France

Abstract: Spectroscopy and optical measurements are amongst the most powerful tools used by geophysicists and astrophysicists to obtain, at distance, information about the planetary atmospheres and about the interstellar medium. Morever spectroscopy also allows us to determine molecular structures and to understand the intra-molecular interactions. The topic of our work concerned mainly molecules containing large amplitude motions and in particular molecules containing one or two methyl (CH3) internal rotors or inversion like in ammonia NH3.

One of the goals of our work is to model the line positions and intensities and to analyse the spectra for these molecules. That way we can provide reliable predictions of line positions and intensities for astrophysical molecules containing one internal rotor CH3, such as the isotopic species of methyl formate HCOOCH3, methanol CH3OH, acetic acid CH3COOH, acetaldehyde CH3CHO, acetamide CH3CONH2 or methyl acetate molecule CH3-O-C(=O)-CH3, which has been very recently detected in the interstellar cloud Orion thanks our prediction.

Another goal of our work is to get some knowledge of the structural properties of small organic molecules or biomimetic molecules. Fourier transform microwave spectroscopy in the gas phase coupled with high level quantum chemical calculations has recently led to the precise determination of molecular structures for the lowest energy conformers of a number of molecules. In this talk, I will show results from molecules which can be considered as prototypes of odorant molecules, like isoamyl acetate (so-called “banana oil”) or linalool, an acyclic mono-terpene present in lavender and other plants and emitted in the earth atmosphere.

Biography: Dr Kleiner is Directeur de Recherches at the Centre National de la Recherche Scientifique (CNRS) and belongs to the Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), Université Paris Est-UPEC and Université Paris Diderot in France. She did her Ph.D at the University Libre de Bruxelles (Belgium) and her post-doctoral fellowship with Dr Jon. T. Hougen at the National Institute for Standards and Technology (NIST, USA). Her field is high resolution spectroscopy and in particular the modelling of the large amplitude motion and internal rotation of one or more methyl groups with application to astrophysical and biomimetic molecules, but also modelling of infrared spectra for planetological applications for C3v molecules such as ammonia NH3, phosphine PH3, acetonitrile CH3CN, etc.

Venue: 806, T5 building, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi

Time: 10h, Tuesday, 27^th February 2018

Speaker: Nguyen Hai Son

Affiliation: Ecole Centrale de Lyon – Institut des Nanotechnologies de Lyon, INL/CNRS

Abstract: Engineering the energy-momentum dispersion of photonic structures is at the heart of photonic research. In contemporary optics, two types of dispersions have been extensively studied: flatband dispersion and Dirac dispersion. The first one gives rise to localized stationary eigenstates which are extremely sensitive to disorder effects due to an infinite effective mass, thus suggests a new regime of light localization.  Being an opposite extreme to flat dispersion, Dirac dispersion corresponds to massless photonic states and enables many exotic physical features such as Klein tunneling, zero-refractive index materials and photonic topological insulator. Other than flatband and Dirac dispersions, most recently, it is also suggested that photonic multi-valley dispersion can provide squeezed light, as well as Josephson oscillation in momentum space.

In this presentation, I will show that symmetry breaking can opens a new degree of freedom to tailor energy-momentum dispersion in photonic crystal. This enables an on-demand tuning of the local density of states of the same photonic band from zero (Dirac cone dispersion) to infinity (flatband dispersion), as well as any constant density over an adjustable spectral range. As a proof-of-concept, we demonstrate experimentally the transformation of the very same photonic band from conventional quadratic shape to a Dirac dispersion, a flatband dispersion and a multivalley one. This transition is achieved by finely tuning the vertical symmetry breaking of the photonic structures. Our results provide an unprecedented degree of freedom for optical dispersion engineering in planar integrated photonic devices. As application, making use of W-shaped dispersion, we demonstrate for the first time a mono-mode micro laser emitting at high oblique angle (20 degrees), operating at room temperature, on Silicon substrate and in the telecom range.

Biography: Hai Son NGUYEN obtained his PhD at the Laboratoire Pierre Aigrain, Ecole Normale Supérieure de Paris in 2011 on single photon emission of semiconductor quantum dots. From 2011-2014, he was CNRS researcher at Laboratoire de Photonique et de Nanostructures, working on polaritonic physics for all-optical integrated circuit and gravitational analogous. He joined Ecole Centrale de Lyon, Institut des Nanotechnologies de Lyon (INL-CNRS, France) as Associate Professor since September 2014. His research topic are Perovskite-based optoelectronic devices, Intergrated silicon photonic and Novel photonic crystal concepts.

Giờ: từ 2 giờ 00 chiều đến 3 giờ 00 chiều

Địa điểm: Phòng 408F, nhà T1, 334 Nguyễn Trãi

Speaker: Dr. Nguyen Quoc Hung (Nano and Energy Center, VNU University of Science and

Niels Bohr Institute, University of Copenhagen)

Title: Topological quantum computing with hybrid semiconductor/superconductor nanowires

Abstract: Performance of quantum devices based on superconducting materials suffer from short decoherence time of it superposition states. Despite monumental effort, short life time of a qubit is a major roadblock to a practical quantum computer. The recent success that combines a semiconductor with a thin layer of superconductor of high quality has lead to new possibilities. Under axial magnetic field, Cooper pairings combined with spin orbit interactions lead to symmetrical excitations along one dimension. Known as Majorana, these quasiparticles extend nonlocally, and thus remain robust against environment fluctuations. It is an attractive candidate to construct a qubit that could have a long decoherence time. Two pairs of Majorana are created in a double dot configuration, which allows a continuous control on their hybridization. The Majorana parity state can be projected to the charge state of each dot, which is readout in the time domain by charge sensing. In the topological regime, we observed Rabi oscillation of a charge qubit, a milestone toward a topological protected qubit.

Venue: 503, T2 building, VNU University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi

Time: 10h, Friday, 5^th January 2018

Speaker: Nhiem Tran

Affiliation: School of Science, RMIT University, Melbourne, Australia

Biography: Dr Nhiem Tran is a Vice-Chancellor’s Research Fellow at the School of Science, RMIT University, Australia. He received a BSc in Physics from Hanoi University of Science in 2005 and a PhD in Physics from Brown University (USA) in 2011. He then worked at Department of Orthopaedics, Rhode Island Hospital (USA) before moving to Melbourne, Australia to join CSIRO and Australian Synchrotron in 2013. The goal of his research is to use advanced technologies to create novel materials that can solve healthcare problems. The materials of interest include self-assembled lipids for drug delivery and in vivo imaging, and coatings for anti-bacterial and tissue regenerating medical implants.

Abstract: Recent advances in nanomaterial research have revolutionised how we diagnose and treat many serious diseases including cancer and bacterial infection. Among these novel nanomaterials, self-assembled lipid nanoparticles have shown potential as drug carriers due to their unique internal mesoporous nanostructures. In water, lipid molecules organise themselves into various structures including a lamellar, inverse bicontinuous cubic, and hexagonal phases. Their nanostructures allow for the controlled release of various drugs, proteins, peptides of both hydrophilic and hydrophobic nature. Additionally, multiple imaging modalities can be encapsulated within the nanoparticles for in vivo contrast enhancement and nanoparticle tracking. Furthermore, bioconjugation of antibodies to lipid nanoparticles allow them to actively recognised molecules on cancer cells or bacteria for targeted delivery of drugs. Since the internal nanostructures directly influence the properties of nanoparticles as drug carriers, it is important to understand the phase behaviour of these nanoparticles in order to further tailor their nanostructures to suit specific biomedical applications. This seminar aims to provide general knowledge regarding the nanostructures created by lipid self-assembly and their potential applications. A special case, in which the nanoparticles are engineered to treat aggressive ovarian cancer, will be discussed.

Người trình bầy: TS Nguyễn Đức Minh, Pohang University of Science and Technology (POSTECH)

Thời gian: 14h ngày thứ 2, 3/7/2017

Địa điểm: P204 nhà T2, Trường Đại học Khoa học Tự nhiên, 334 Nguyễn Trãi.

Place: Room 301, T1 building, VNU University of Science, 334 Nguyen Trai street, Hanoi, Vietnam

First presentation: Boviet Solar Technology and its R&D activities

By: Dr Wu Chung-Han, Director of R&D

Second presentation: R&D activities on solar cells at NEC

By: Dr NGUYEN Tran Thuat, Solar cell group leader

Abstract:

During this workshop, the activities R&D of solar cell and of materials applied in solar technology are presented. On one hand, Boviet Solar Technology, which was founded in 2011 and is currently running the biggest solar factory in Vietnam with capacity of 200MW, would like to develop its R&D in order to optimize the solar cells process and to increase the efficiency. On the other hand, Nano and Energy Center, which was also founded in 2011, develops research themes on silicon solar cells and other new materials for applications in solar cells. There are some common points between the two parties, and these points would be developed more in future.

Website of Boviet Solar Technology

By: Prof. Bernard Drevillon, (LPICM), Ecole Polytechnique (X)

Time: 14h PM, Friday, 17th May 2016

Place: Room 408f, T1 building, VNU University of Science

Abstract:

In the last years Polarimetric Imaging has received considerable attention in the literature thanks to its tremendous potential for the assessment of biological tissues in biomedical diagnostics. Light Polarization allows obtaining morphological information on tissues microscopic structure, potentially improving the diagnosis and treatment of several pathologies. Moreover, polarimetric imaging can be implemented using conventional light sources, like LED or halogen lamps, making it a cheap alternative to current standards. For several years the PICM Laboratory has designed and built innovative polarimetric imagers for biomedical applications. In particular, the development of the eigenvalue calibration method  led to the design of several polarimeters for macroscopic and microscopic analysis (in real and Fourier space) of ex vivo samples and for in vivo diagnoses. The development of such new instruments ranged from the simple measurement of polarization degree to the complete Mueller polarimetry.

Several studies were devoted to the early detection and staging of uterine cervix cancer and to show that polarimetric imaging is effective for the visualisation and first grading of cervical dysplastic regions for patients with anomalous Pap smear. Mueller matrix imaging polarimetry also provides enhanced contrast to differentiate types of cancer of colon and their stage of progress and penetration, which is currently detectable only by histological examination. Moreover, this technique may also be useful to quickly verify the presence of residual cancer in the rectum after treatment with radiochemotherapy. Finally, as a promising development of these experimental techniques, first results of Mueller polarimetric endoscopy are presented.

In conclusion the synergy of new experimental techniques based on polarimetry with the biomedical analysis and theoretical computer models, led to significant advances in the field of biological tissues characterization and diagnosis of related pathologies.   

About Prof. Bernard Dreviloon, link on wiki, research team link

By: Prof. László Forró, Director of Laboratory of  Physics of Complex Matter (LPMC), Ecole Polytechnique federale de Lausanne (EPFL)

Time: 10h AM, Monday, 14th March 2016

Place: Room 401, T1 building, VNU University of Science

Abstract:

In the last few years, the organolead halide perovskite CH3NH3PbI3 and its derivatives have been found to be very efficient light harvesters and ambipolar semiconductors revolutionizing the field of solid-state solar cells. Its low temperature fabrication process allowed to design simpler solar cell structures (i.e. from mesoscopic to planar junctions) which yielded efficiencies approaching 20%. 

We have shown that one can synthesize nanowires of this photovoltaic perovskite (Horváth et al, in Nano Letters DOI: 10.1021/nl5020684) which in association with carbon nanostructures (carbon nanotubes and graphene) makes outstanding composites with rapid and strong photoresponse. They can serve as conducting electrodes and as central components of sensors, detectors. The demonstration of the performance of several devices based on these composite structures will be given.

Website of Prof. László Forró

By: Dr LAI Ngoc Diep

Time: 10h AM, Wednesday, 23rd December 2015

Place: Room 408F, T1 building, VNU University of Science

Abstract: In relation with the strong and fast development of sub-diffractive fabrication techniques, a great deal of interest has been devoted to suitable and inexpensive materials, which may form desired micro and nanostructures. Polymer materials offer unique opportunities in nanophotonics since both top-down and bottom-up strategies can be pursued and combined towards the nanoscale. Besides, polymer materials can be, with simple methods, functionalized with nonlinear optical or fluorescent materials (organic, inorganic, or metal). The ensemble can be optically structured in a flexible way to obtain a polymer-based photonic nanostructure (“host”) containing active materials (“guest”). The engineered coupling between a guest moiety (molecule, nanoparticle) and the host photonic nanostructure may provide an enhancement of the guest optical response, leading to attractive applications. In this seminar, I will explain two important fabrications techniques, namely interference and one-photon absorption direct laser writing, which present different advantages and allow to obtain desired sub-micrometric 2D and 3D structures. I also discuss about some potential applications of these polymer-based structures, for example, laser, nonlinear optics, plasmonics, as well as quantum optics (single photon source).

Website of Dr LAI Ngoc Diep

By: Dr Phong Tran

Time: 10h AM, thursday, 16th April 2015

Place: 204, T2 building, VNU University of Science, 334th Nguyen Trai street, Hanoi

Abstract: 

This talk will highlight some of our research in developing materials for applications in medical implants, tissue engineering and drug delivery. The first example will discuss our study of using nanometer structured selenium as a promising material for implants in bone-cancer patients. Experimental results showed much promise for selenium nanocluster coatings on traditional implants. Experimental results of this study were complemented by computer simulation results of protein interactions on the nanometer rough surfaces created by selenium nanocluster coatings. Specifically, here it was demonstrated that selenium nanocluster coatings can be readily applied to bone implant metallic materials (titanium, stainless steel). Selenium nanoparticles were prepared using similar synthesis processes. Biological experiments showed that the selenium coatings on titanium promoted healthy bone cell functions. The increase in healthy bone cell functions on selenium coated surfaces was shown to be attributed to the increase in adsorption of fibronectin, one of the most important cell adhesive proteins that regulate interactions between bone cells and an implant surface. The increase in fibronectin adsorption was hypothesized to be due to the increase in root-mean-square (RMS) nanometer roughness of the selenium coated surfaces compared to the uncoated surfaces. To test this hypothesis, computer simulation was used to simulate the adsorption of fibronectin on the generated surfaces. Simulation results showed good agreement with experimental results. Moreover, results demonstrated decreased bone cancer cell functions while increased healthy bone cell functions on selenium coated implants. The decrease in cancerous bone cell growth was shown to be due to the release of selenium into cell culture media. Healthy bone cells were not affected by the released selenium in culture media. In the second example, I will discuss our study in using biomaterials as antimicrobial agents instead of antibiotics for biomedical applications. Antibiotics have successfully been used to treat infections. However, with the increasingly high number of bacteria that are resistant to multiple drugs, new type of antimicrobial agents are being developed. We focus on studying metallic materials that exhibit antimicrobial activities. First, I will discuss the antimicrobial activity of selenium coatings on polymeric substrates (including PVC, PU and silicone) against S. aureus, an important bacterium that infects all implants, especially catheters. I will then discuss our work in the new silver-based hybrid materials for controlled antimicrobial delivery. The findings from our studies suggest that these biomaterials have the potential to be used in a wide range of medical implants/devices for anti-cancer and/or antimicrobial purposes. Finally, I will present some of our new research direction in development of materials for soft/hard tissue regeneration such as for skin/fat/bone regeneration.

Short bio: 

Dr. Phong Tran is a Vice-Chancellor’s Research Fellow at The Institute of Health and Biomedical Innovation, Queensland University of Technology. Before taking up this position, he was a McKenzie Research Fellow in the Department of Chemical and Biomolecular Engineering, the University of Melbourne. Dr. Tran’s research has been focused on developing advanced materials for applications in medical devices, tissue regenerations and drug delivery. His research has attracted more than $500,000 in funding, resulted in more than 20 publications, 380+ citations, two international patents, two spin-off companies with commercial products available. Dr. Tran earned his PhD from Brown University (USA) in 2010 and migrated to Australia in 2011. He is now living in Brisbane with his wife and daughter.