ASIAA/CCMS/IAMS/LeCosPA/NTU-Phys/NTNU-Phys Joint Colloquia

September 18, 2018

Kwo-Ray Chu 

NTU-physics

Host:  Yuan-Huei Chang
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
High Frequency Microwave Heating 
- A Research Tool, Preliminary Results, 
  and Potential for Collaboration

Abstract

An excessive temperature spread due to uneven energy deposition has been a persistent obstacle to most microwave heating applications. We present a theoretical and experimental study aimed at a deeper understanding of the causes for this difficulty and a fundamentally different approach to overcome it.
The main research tool is a microwave applicator, which features the rarely-used ISM frequency of 24 GHz with a heating rate about 2-3 orders of magnitude faster than the mainstream frequencies of 2.45 GHz and 27 MHz. High radiation uniformity (~99%), polarization control, and real-time IR images allow highly repeatable data acquisition for scientific analyses. Preliminary results on the study of a major but hitherto unnoticed cause for non-uniformity (polarization charge shielding) and an effective remedy will be reported.
Research is being conducted with colleagues in the College of Bioresources and Agriculture on microwave control of grain insects, seed-borne bacteria, and dragon fruit virus. Some encouraging initial results will also be reported. d We are looking forward to collaborations with interested colleagues on more applications such as pest control of museum artifacts and microwave treatment of 2D materials.

Brief Bio

Experience
1973-1977, Research Scientist, Science Applications International Corporation, Virginia, U.S.A.
1977-1983, Supervisory Research Physicist, U.S. Naval Research Laboratory, Washington, D. C., U.S.A.
1983-2010, Professor/Distinguished Chair, Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
2010-present, Distinguished Chair, Department of Physics, National Taiwan University, Taipei, Taiwan

Research
Kwo Ray Chu specializes in plasma physics and, in particular, the generation of coherent electromagnetic waves via the electron cyclotron maser (ECM) interaction. The ECM is based on a stimulated cyclotron emission process involving energetic electrons in gyrational motion. It constitutes a cornerstone of relativistic electronics, a discipline that has emerged from our understanding and utilization of relativistic effects for the generation of coherent radiation from free electrons. Over a span of four decades, the ECM has undergone a remarkably successful evolution from basic research to device implementation while continuously being enriched by new physical insights. By delivering unprecedented power levels, ECM-based devices have occupied a unique position in the millimeter and submillimeter regions of the electromagnetic spectrum, and find use in numerous applications such as fusion plasma heating, advanced radars, industrial processing, materials characterization, particle acceleration, and tracking of space objects.

September 25, 2018

Stefano Profumo

UC Santa Cruz

Host:  Cheng-Wei Chiang
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
What is the Dark Matter?

Abstract

Four fifths of the matter in the universe is made of something completely different from the "ordinary matter" we know and love. I will explain why the dark matter is an unavoidable ingredient to explain the universe as we observe it, and I will describe what the fundamental, particle nature of the dark matter could possibly be. I will then give an overview of strategies to search for dark matter as a particle, describe a few examples of possible hints of discovery, and outline possible ways forward in this exciting hunt.

Brief Bio

Dr. Stefano Profumo is a Professor of Physics at the University of California, Santa Cruz, and the Deputy Director for Theory of the Santa Cruz Institute for Particle Physics. Dr. Profumo earned his MS from Scuola Normale Superiore in Pisa, Italy, in 2001, and a PhD in Elementary Particles Theory from the International School for Advanced Studies in Trieste, Italy, in 2004. He joined the faculty at the University of California in 2007 after two postdoctoral positions, one at Florida State University (2004-5) and one at the California Institute for Technology (2005-7).
Dr. Profumo’s research work spans particle physics theory, cosmology, and high-energy astrophysics. He has published over 150 peer-reviewed articles, many of which on the topic of particle dark matter; his research work has been cited more than 14,000 times, according to Google Scholar. He is the author of the textbook "An Introduction to Particle Dark Matter".
Dr. Profumo is also an avid runner, biker, and triathlete.

Live Streaming and Video

October 02, 2018

Spencer Chang 

University of Oregon

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Learning Physics from Machine Learning

Abstract

Machine learning is a powerful technique which is increasingly important in everyday life as well as scientific research. Despite enormous recent progress, in particular involving deep neural networks, it remains a challenge to understand what the machine is "learning."
I will first give a brief review of neural networks. Then, focusing on classification problems (e.g. signal vs. background), I will describe a technique called "data planing" which allows one to test the importance of any given physics variable in a classification scenario. Thus, this allows one to reverse engineer the relevant information that the neural network has "discovered."
As a demonstration, I will use a simple particle physics search to illustrate the procedure in action. At the end of the talk, I will discuss future directions in data planing as well as other ideas on how to better understand/utilize machine learning in physics.

Brief Bio

Education and Academic Positions
1995-1999 Stanford University - B.S. in Physics
1999-2004 Harvard University - PhD in Theoretical Particle Physics (Advisor: Howard Georgi)
2004-2008 New York University - Postdoc
2008-2011 University of California at Davis - Postdoc
2011-2017 University of Oregon, Assistant Professor of Physics
2017-current University of Oregon, Associate Professor of Physics
2018-2019 National Taiwan University, Courtesy Associate Professor of Physics

Live Streaming and Video

October 09, 2018

Jordi Miralda Escudé

University of Barcelona

Host:  Naomi Hirano
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Clues to the Small-Scale Mass Distribution of 
the Dark Matter Probed by Gravitational Lensing

Abstract

Dark matter continues to pose one of the most important questions in modern cosmology. Gravitationally lensed multiple images of galaxies, quasars and stars provide several opportunities for testing the clumpiness of dark matter on small scales due to, for example, compact objects, axion mini-clusters and waves, or subhalos orbiting on galactic or cluster dark matter halos. The idea of using highly magnified stars by lensing clusters to probe this small-scale granularity in the dark matter will be discussed.

Brief Bio

After studying Physics in Catalonia, Dr. Jordi Miralda Escudé obtained his doctorate at Princeton University and did postdoctoral research at the University of Cambridge and the Institute for Advanced Study. He was professor at the University of Pennsylvania and at the Ohio State University, and he returned to Barcelona with an ICREA research professor position. Dr. Miralda Escudé’s research interests are on the intergalactic medium, gravitational lensing, galactic dynamics and dark matter.

Live Streaming and Video

October 16, 2018

Goan Hsi-Sheng

 NTU-Physics

Host:  Yuan-Huei Chang
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Overview and Recent Developments 
in Quantum Computers and 
Quantum Computing

Abstract

Advances in quantum algorithms which outperform their best known classical counterparts have prompted scientists to build a practical quantum computer. Shor’s quantum factoring algorithm, for example, can enabled a quantum computer, if available, to break the cryptographic keys and thus compromise the security of the currently existing cryptosystems. Due to exponential growth of the number of basis states in Hilbert space with the quantum bit (qubit) number n, the computational capabilities of a 100-qubit quantum computing system for some problems are already beyond those of today’s classical computing systems, achieving "quantum supremacy". In other words, 100-qubit or more-qubit quantum processors, available in the next 5 to 10 years, may be able to solve some problems that cannot be solved by today's most powerful supercomputers.
In this talk, I will give an overview and recent developments in building practical quantum computers and recent progress in the emerging and exciting field of quantum computing. In particular, I will describe and discuss the prospects and challenges for realizing a quantum computer using semiconductor silicon-based quantum-dot spin qubits.

Brief Bio

Professor Hsi-Sheng Goan received his Ph.D. degrees in Physics from the University of Maryland, College Park, USA in 1999. He then worked as a postdoctoral research fellow at the University of Queensland, Brisbane, Australia from 1999-2001. From 2002-2004, he was a senior research fellow awarded the Hewlett-Packard Fellowship at the Center for Quantum Computer Technology at the University of New South Wales, Sydney, Australia before he took up a faculty position at the Department of Physics, National Taiwan University in 2005. He is currently a Professor of Physics at NTU working in the fields of Quantum Computing and Quantum Information Theory, Quantum Control, Mesoscopic (Nano) Physics, and Quantum Optics (Theory).

October 23, 2018

Jyhpyng Wang

IAMS, Academia Sinica

Host:  Yuan-Huei Chang
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Intense Laser Based on Chirped 
Pulse Amplification

Abstract

The 2018 Nobel Prize in Physics was awarded with one half to Arthur Ashkin "for the optical tweezers and their application to biological systems" and the other half jointly to Gérard Mourou and Donna Strickland "for their method of generating high-intensity, ultra-short optical pulses". In this colloquium talk I shall (1) introduce the basic physics of ultra-short pulse lasers, (2) explain why the method invented by Gérard Mourou and Donna Strickland, known as chirped pulse amplification, was a breakthrough to producing high-intensity, ultra-short optical pulses, and (3) discuss the applications and prospect their method has led to, including high-gradient accelerators, short-pulse X-ray and extreme-UV sources, and frequency-tunable gamma-ray beam.

Brief Bio

Dr. Jyhpyng Wang is a research fellow of Institute of Atomic and Molecular Sciences, Academia Sinica, with joint appointments in the physics departments of National Taiwan University and National Central University. He was an early pioneer of femtosecond mode-locked Ti:sapphire laser and led a team to build a 100-TW laser system at National Central University for research in laser accelerator, short-pulse x-ray/extreme-UV sources, and plasma nonlinear optics.

Live Streaming and Video

October 30, 2018

Ken’ichi Nomoto

IPMU

Host:  Naomi Hirano
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
First Stars: Models of Supernova 
Explosions and Constraints from 
Extremely Metal-Poor Stars

Abstract

The first stars in the Universe must have played crucial roles in the evolution of early universe, yet their nature has not been well-understood. I will present possible theoretical models of first stars, i.e., their evolution with mass accretion, explosions as first supernovae, and explosive nucleosynthesis. I will show how the comparison between the nucleosynthesis yields and the peculiar abundance patterns observed in extremely metal-poor stars can constrain the properties (mass function, explosion energy, asphericity, etc.) of first stars and first supernovae.

Brief Bio

Experience
1974 PhD in Astronomy at the University of Tokyo; Post Doc at the University of Tokyo
1976 Assistant Professor at Department of Physics, Ibaraki University
1982 Assistant Professor at Department of General Systems Studies, University of Tokyo
1985 Associate Professor at Department of Earth Science and Astronomy, University of Tokyo
1989 Associate Professor at Department of Astronomy, University of Tokyo
1993 Professor at Department of Astronomy, University of Tokyo
2008 Professor at Kavli IPMU, University of Tokyo
2017 Senior Scientist at Kavli IPMU, University of Tokyo; Professor Emeritus of the University of Tokyo

Received the following prizes for the theoretical work on stellar evolution, supernova explosion, nucleosynthesis, and gamma-ray bursts
1989 Nishina Memorial Prize
1995 Japan Academy Prize
2010 IAP Medal (Institut d'Astrophysique de Paris)
2015 Marcel Grossmann Award
2019 Hans A. Bethe Prize (American Physical Society)

Live Streaming and Video

November 13, 2018

David Jewitt

UCLA

Host:  Wei-Hsin Sun
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Two Freaks and a Conundrum

Abstract

In this talk, I will discuss three recent solar system investigations having very surprising results. The first relates to a bizarre asteroid whose morphology is not accounted for by any model. The second concerns an amazing comet, whose activity is actually impossible according to established models. The third addresses the origin of the Trojans.

Brief Bio

Education
1979 B. Sc. University College London
1980 M. S. California Institute of Technology
1983 Ph. D. California Institute of Technology

Honors
1994 Regent's Medal, University of Hawaii
1996 Scientist of the Year, ARCS
1996 Exceptional Scientific Achievement Award, NASA
1998 Fellow of University College London
2005 Fellow of the American Academy of Arts and Sciences
2005 Fellow of the American Association for the Advancement of Science
2005 Member of the National Academy of Sciences
2006-2011 National Observatory, Chinese Academy of Sciences, Honorary Professor
2007 National Central University, Taiwan, Adjunct Professor
2012 The Shaw Prize for Astronomy
2012 The Kavli Prize for Astrophysics
2012 Foreign Member, Norwegian Academy of Sciences & Letters

Research Interests
Solar System Formation, Trans-Neptunian solar system
Physical properties of comets and cometary dust
Comet - asteroid interrelations, Centaurs, irregular satellites, Trojans, Active Asteroids
Submillimeter properties of comets and young stars

Live Streaming and Video

November 13, 2018

Dr. Julie Kim-Zajonz

Managing Editor, Physical Review Applied

Host:  Din Ping Tsai
Time: 3:50 pm -4:50 pm
Place: Room 104, CCMS-New Phys. building
Title:
The Physical Review Family of Journals: 
An Insider’s Look

Abstract

You have done the hard work and now have some results you want to share with the world. It is time to write up your paper and get it published! In this talk, I will present a quick overview of the Physical Review family of journals. We will then explore the inner workings of the publication process, from the perspectives of an author and of a referee. What should you keep in mind when preparing a manuscript? What can you expect during the refereeing process? If you are called upon to be a referee, how can you best facilitate the process? What do the editors want to help us make an informed decision?

Brief Bio

Julie Kim-Zajonz received her Ph.D. from the University of Munich, working on high-pressure x-ray diffraction. She was born in Hong Kong, has Korean ancestry, and grew up in England, Hong Kong, and Los Angeles. She began working for Physical Review B in 1999, and has been Editor of PRB Rapid Communications since 2002. As Editor of that section, she handled a wide range of subject areas including semiconductors, metamaterials, surfaces, nanomaterials, and molecular electronics. In November of 2013 she became the Managing Editor of Physical Review Applied.

November 27, 2018

Yann‐Wen Lan  

NTNU-Physics

Host:  Ya-Ping Hsieh
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Device Physics and Potential 
Applications Based on Novel 
2D Materials Nanoelectronics

Abstract

The 20^th century ushered in the Information Age with the silicon electronics industry’s aggressive and persistent scaling down of the Complementary Metal-Oxide-Semiconductor Field-Effect Transistors’ (MOSFET) dimensions. However, we now face the impending stall of Moore’s Law and must find alternative materials and novel device concepts which may augment commercial silicon technology for enabling high performance and low power consumption. During the last decade, tremendous research efforts have been focused on two-dimensional (2D) materials due to their rich physics and great potentials for many applications. Accordingly, in this talk we present some experimental results of 2D materials electronics, including high performance MoS₂ field effect transistors _[1], quasi-heterojunction bipolar transistor _[2], tunnelling field effect transistor _[3], vertical hot electron transistor _[4], photodetector _[5], magnetic property for spintronics _[6], piezoelectric effect _[7] and quantum tunnelling behaviour _[8]. Our results suggest that electronics based on 2D materials could potentially lead to energy generation and low power dissipation for future device applications.

Reference:
[1] “Effective N-Methyl-2-pyrrolidone wet cleaning for fabricating high-performance monolayer MoS2 transistors”, https://doi.org/10.1007/s12274-018-2215-5. Nano Research (2018).
[2] “Atomic-Monolayer Two-Dimensional Lateral Quasi-Heterojunction Bipolar Transistors with Resonant Tunneling Phenomenon”, ACS Nano, 11(11), 11015-11023, 2017
[3] “Atomic-monolayer MoS2 band-to-band tunneling field-effect transistor”, SMALL, doi:10.1002/smll.201601310, 2016.
[4] “High-current gain two-dimensional MoS2-base hot-electron transistors”, Nano Letters 15, 7905-7912, 2015.
[5] “Self-aligned graphene oxide nanoribbon stack with gradient bandgap for visible-light photodetection”, Nano energy, 27, 114-120, 2016
[6] “Strong Rashba-Edelstein Effect-Induced Spin-Orbit Torques in Monolayer Transition Metal Dichalcogenides/Ferromagnet Bilayers”, Nano Letters, 16(12), 7514-7520,2016.
[7] “Piezoelectric effect in CVD-grown atomic-monolayer triangular MoS2 piezotronics”, Nature Communications, 6, pp7430, 2015.
[8] “Resonant tunneling through discrete quantum states in stacked atomic-layered MoS2”, Nano Letters, 14(5), pp 2381-2386, 2014.

Brief Bio

Yann-Wen Lan is an Associate Professor in National Taiwan Normal University in Taiwan. He received the B.S. and M.S. degrees from Chemical Engineering, National Taipei University of Technology, Taipei, Taiwan, in 2002 and 2004, respectively. He earned the Ph.D. degree from the Institute of Electrical Engineering, National Taiwan University, Taipei, Taiwan, in Jan 2012. From Feb 2012 to Feb 2014, he was a postdoc researcher at Institute of Physics, Academic Sinica in Taiwan. From March 2014 to June 2016, he was a postdoc research fellow in Device Research Laboratory at UCLA. From July 2016 to July 2017, he was a Research Fellow in the National Nano Device Laboratories in Taiwan. His research interests include fundamental physics and practical applications based on 1D nanowire/nanotube, 2D layered materials and energy nanoelectronics.

December 04, 2018

Ji-Xin Cheng

Boston University

Host:  Shi-Wei Chu
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Label-Free Chemical Imaging: 
Unveiling Hidden Signatures 
for Molecule-Based Diagnosis 
and Treatment

Abstract

Optical microscopy has been a fundamental tool to life science and materials science since its invention in the 17th century. Various labeling approaches have enabled selective visualization of cellular structures or biomolecules with high specificity under a light microscope. Despite great advances made recently, the labeling approach also has limitations: First, labels may perturb the function of a biological molecule or structure; Second, the labeling approach offers limited capacity of discovery because it is only applicable to mapping known species; Third, delivery of labels to a target could be difficult, especially under in vivo conditions; Fourth, potential toxicity often prevents the use of labels on human patients. Chemical microscopy, based on intrinsic molecular spectroscopic signals, opens a way to circumvent these barriers. I will present various advanced modalities of chemical microscopy, discoveries of hidden signatures in living organisms, and translation into clinic for molecule-based diagnosis and treatment. Additionally, I will present novel use of photons for eradication of drug-resistant bacteria and stimulation of neurons in brain.

Brief Bio

Ji-Xin Cheng attended University of Science and Technology of China (USTC) from 1989 to 1994. From 1994 to 1998, he carried out his PhD study on bond-selective chemistry under the supervision of Qingshi Zhu at USTC. As a graduate student, he worked as a research assistant at Universite Paris-sud (France) on vibrational spectroscopy and the Hong Kong University of Science and Technology (HKUST) on quantum dynamics theory. After postdoctoral training on ultrafast spectroscopy in Yijing Yan’s group at HKUST, he joined Sunney Xie’s group at Harvard University as a postdoc, where he and others developed CARS microscopy that allows high-speed vibrational imaging of cells and tissues. Cheng joined Purdue University in 2003 as Assistant Professor in Weldon School of Biomedical Engineering and Department of Chemistry, promoted to Associate Professor in 2009 and Full Professor in 2013. He joined Boston University as the Inaugural Theodore Moustakas Chair Professor in Photonics and Optoelectronics in summer 2017. Professor Cheng and his team has been constantly at the most forefront of the rising field of label-free optical spectroscopic imaging in technical innovation, discovery, and clinical translation.
Professor Cheng has been recognized by Fellow of Optical Society of America (2018), SPIE Translational Research Awards (2018, 2016, 2014), Purdue University College of Engineering Research Excellence Award (2016), Craver Award from Coblentz Society (2015), Chang-Jiang Scholar from Chinese Minister of Education (2015), Fellow of American Institute of Medicine and Biological Engineering (2014), Purdue University Faculty Scholar (2012-17), College of Engineering Early Career Research Award (2011), Research Excellence Award from Purdue Center for Cancer Research (2011), Outstanding Young Scientist Award from Chinese National Academy of Sciences (2009).

Live Streaming and Video

December 11, 2018

I-kai Lo 

NSYSU- Physics

Host:  Yuan-Huei Chang
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
High-efficiency III-Nitride 
Phosphor-Free Cold-White-light 
Micron LEDs

Abstract

GaN exhibits a stable wurtzite structure as a new-generation and energy-saving white light source, e.g., light-emitting diode (LED). The commercial white-light LEDs are mostly made of a phosphor-assisted InGaN/GaN quantum well (QW) with cerium-doped yttrium aluminum garnet (YAG). However, the phosphor-assisted white-light InGaN/GaN LED will lose its efficiency in the electrical-to-luminous energy transferring by the coating phosphor. We have developed a technique to grow individual red-green-blue InGaN/GaN micro-disk QWs, which can produce the white light without the assistance of any phosphor for the energy sustainable lighting source. The GaN micro-disk showed a high efficient luminescence for phosphor-free white-light LED applications.

Brief Bio

Dr. Ikai Lo (Ph.D. in Physics) is a professor of Physics Department, National Sun Yat-Sen University, Kaohsiung, Taiwan, and the principal investigator of Innovation and Application of Nanoscience Thematic Program, MOST (科技部奈米科技創新應用主軸計畫). He received his BS degree in Physics, National Tsing Hua University, Hsin-Chu, Taiwan (1980), and Ph. D. degree in Physics, State University of New York at Buffalo, NY, USA (1989). He served as a National Research Council (Washington, D.C.) post-doctoral fellow in Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio, USA (1989 – 1993) with an honor of National Research Council (Washington D.C., USA) associateship award. He became a faculty of Physics Department, National Sun Yat-Sen University, Taiwan since 1989, Chairman of Physics Department (2000 – 2002), and Dean of Science College (2011 – 2014). Dr. Ikai Lo has been assigned as Director of the Center for Nanoscience and Nanotechnology (NSYSU), since 2017.

Live Streaming and Video

December 18, 2018

Wen-Hao Chang 

NCTU-Electrophysics

Host:  Woei-Wu Pai
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
2D Layered Semiconductors beyond MoS₂

Abstract

2D layered materials, particularly semiconducting transition metal dichalcogenides (TMDs), such as MoS₂ and WSe₂, have attracted tremendous research works, due not only to their atomically thin thickness, but also to many exciting new phenomena associated with new materials. Recent advances in heterostructures formed by vertically stacked or laterally stitched 2D semiconductors further show their promise for novel device applications. In this talk, I will present our recent endeavors on the material synthesis and fundamental study of 2D TMDs. In particular, I shall demonstrate our recent progress on new TMDs, such as PtSe₂ and PdSe₂ grown of by chemical vapor deposition. In the second part, I will demonstrate some progress on new coupled spin-valley physics in TMD vertical heterojunctions caused by the interlayer quantum inference. Interlayer coupling and Moiré superlattice in twisted hetero-bilayers will be presented.

References: 1. W.-T. Hsu, L.-S. Lu, P.-H. Wu, M.-H. Lee, P.-J. Chen, P.-Y. Wu, Y.-C. Chou, H.-T. Jeng, L.-J. Li, M.-W. Chu & W.-H. Chang*, Nature Comm. 2018, 9, 1356.
2. W.-T. Hsu, L.-S. Lu, D. Wang, J.-K. Huang, M.-Y. Li, T.-R. Chang, Y.-C. Chou, Z.-Y. Juang, H.-T. Jeng, L.-J. Li & W.-H. Chang*, Nature Comm. 2017,8, 929.
3. W.-T. Hsu, Y.-L. Chen, C.-H. Chen, P.-S. Liu, T.-H. Hou, L.-J. Li & W.-H. Chang*, Nature Comm. 2015, 6, 8963.
4. M.-Y. Li, Y. Shi, C.-C. Cheng, L.-S. Lu, Y.-C. Lin, H.-L. Tang, M.-L. Tsai, C.-W. Chu, K.-H. Wei, J.-H. He, W.-H. Chang, K. Suenaga, L.-J. Li*, Science 2015, 349, 524-528.

Brief Bio

Dr. Chang is currently a distinguished professor of physics at National Chiao Tung University (NCTU), Taiwan. He received his BS (1994), MS (1996) and PhD (2001) degrees in Physics from National Central University (NCU), Taiwan. After his postdoctoral research at NCU, he joined the Department of Electrophysics at NCTU as an assistant professor in 2005 and became a full professor since 2012. His research interests include light-matter interactions in semiconductor nanostructures, nanophotonics/plasmonics hybrid systems, and 2D layered materials. He has authored and co-authored more than 100 journal papers and received citation more than 4,800 times with an h index of 31, according to Google Scholar. He was awarded the Ta-Yu Wu Memorial Award of the Ministry of Science and Technology of Taiwan in 2010 and Sun Yet-Sen Academic Award in 2018. Dr. Chang is the Editor of Chinese Journal of Physics and the Editorial Board Members of Scientific Report. Dr. Chang now also serves as the Convener of the Physics Discipline of the Ministry of Science and Technology of Taiwan.

December 25, 2018

Li-Chyong Chen

 CCMS

Host:  Woei-Wu Pai
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Two-Dimensional Nanomaterials for 
Artificial Photosynthesis: 
Turning CO₂ into a Valuable Resource

Abstract

Photocatalytic CO₂ conversion to hydrocarbon fuels, the so-called artificial photosynthesis or solar fuels, making possible simultaneous solar energy harvesting and CO₂ reduction reaction (CO2RR), is considered a killing two birds with one stone approach to solving the energy and environmental problems. However, the development of solar fuels has been hampered by the low photon-to-fuel conversion efficiency of the photocatalysts and lack of the product selectivity. Here, I would like to present recent progress in developing two-dimensional (2D) nanomaterials for CO2RR application. Criteria in the choice of materials and the scientific issues regarding the interface physics and chemistry (e.g., the interaction of light with semiconductor and gaseous species) involved in the process of CO2RR will be addressed. Notably, defect engineering (interstitial, substitutional, and vacancy) in 2D chalcogenides was found to be a viable method towards promising photocatalysts for CO2RR. Two cases will be illustrated: the carbon-doped SnS₂ nanosheets and single/few-layer MoS₂ with vacancies controlled by plasma treatment. The role and interplay of the defects and the hosting 2D materials as well as their effects on CO2RR will be presented.

Brief Bio

Dr. Li-Chyong Chen is currently a Distinguished Research Fellow at the Center for Condensed Matter Sciences (CCMS) in National Taiwan University (NTU). She received her B.S. in Physics from NTU (1981), and Ph.D. in Applied Physics from Harvard University (1989); afterwards, she worked at the Materials Research Center in General Electric Corporate R&D, Schenectady, New York (1989–1994), before she joined the CCMS, NTU. Li-Chyong’s group is specialized in low-dimensional nanomaterials and their applications for optoelectronics, energy and sensing. Till date she has 14 patents, 15 book chapters/review articles and over 390 papers, with a total citations over 14,050 and an H-index of 62 by WOS. Selective honors Li-Chyong has received are: an Honorary Doctorate from Linköping University in Sweden, an outstanding alumnus of her alma mater in NTU, and she is also elected as a Fellow of the Physical Society of Taiwan (TPS), Taiwan Vacuum Society and the Materials Research Society (MRS) in USA.
Li-Chyong received twice the Ministry of Science and Technology Outstanding Research Award (2007, 2010), Laureate of the 22^nd Khwarizmi International Award, Iran (2009), Outstanding Scholar Foundation Award (2010), Ho Chin-Tui Outstanding Scholar Award in Materials Science (2012), Acharya Vinova International Award in Materials Science and Technology (2013), Academician of Asia Pacific Academy of Materials (2015), Taiwan Outstanding Women in Science (2017) and most recently, the Ministry of Education Academic Award (2018). Finally, Li-Chyong has actively served the professional communities, such as the Vice President of the TPS (2006-2007), Meeting Chair of the MRS-Fall (2009), Editor of Book Series in Nanoscience and Nanotechnology, World Scientific Publishers (since 2015), MRS Board of Directors (2017-2019), the Commission on Structure and Dynamics of Condensed Matter, International Union of Pure Applied Physics (2017-2020), and Board of Trustees of the National Synchrotron Radiation Research Center in Taiwan (since 2018).