Kavli Nanoscience Institute

Pasadena, CA, United States

Kavli Nanoscience Institute

Pasadena, CA, United States
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Burgos S.P.,Applied Materials | Batara N.A.,Applied Materials | Atwater H.A.,Applied Materials | Atwater H.A.,Kavli Nanoscience Institute | And 2 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2013

Photoresponsive materials that adapt their morphologies, growth directions, and growth rates dynamically in response to the local incident electromagnetic field would provide a remarkable route to the synthesis of complex 3D mesostructures via feedback between illumination and the structure that develops under optical excitation. We report the spontaneous development of ordered, nanoscale lamellar patterns in electrodeposited selenium-tellurium (Se-Te) alloy films grown under noncoherent, uniform illumination on unpatterned substrates in an isotropic electrolyte solution. These inorganic nanostructures exhibited phototropic growth in which lamellar stripes grew toward the incident light source, adopted an orientation parallel to the light polarization direction with a period controlled by the illumination wavelength, and showed an increased growth rate with increasing light intensity. Furthermore, the patterns responded dynamically to changes during growth in the polarization, wavelength, and angle of the incident light, enabling the template-free and pattern-free synthesis, on a variety of substrates, of woodpile, spiral, branched, or zigzag structures, along with dynamically directed growth toward a noncoherent, uniform intensity light source. Full-wave electromagnetic simulations in combination with Monte Carlo growth simulations were used to model light-matter interactions in the Se-Te films and produced a model for the morphological evolution of the lamellar structures under phototropic growth conditions. The experiments and simulations are consistent with a phototropic growth mechanism in which the optical near-field intensity profile selects and reinforces the dominant morphological mode in the emergent nanoscale patterns.

News Article | October 28, 2015
Site: news.mit.edu

The School of Engineering will add an exceptionally large class of new faculty to its ranks during the 2015-16 academic year. Eighteen engineers whose skills span scholarship, invention, innovation, and teaching will contribute to new directions in research and education across the school and to a range of labs and centers across the Institute. “We are welcoming a large and remarkably talented group of young faculty to engineering this year,” says Ian A. Waitz, dean of the School of Engineering. “They are working on an amazing range of exciting topics with direct applications to the world, from medical devices, to energy storage, to data optimization, to biofabrication strategies, and more. Their energy and enthusiasm for solving practical problems is an inspiration — to me, and to our students.” The new School of Engineering faculty members are: Michael Birnbaum will join the Department of Biological Engineering faculty as an assistant professor and become a core member of the Koch Institute for Integrative Cancer Research in January 2016. He received an BA in chemical and physical biology from Harvard University and a PhD in immunology from Stanford University, where he received the Gerald Lieberman Award, given to the school’s most outstanding medical school PhD graduate. Birnbaum’s research combines protein engineering, structural biology, and bioinformatics to understand and manipulate immune-cell responses to antigenic stimuli in cancer and infectious disease. He will teach the Department of Biological Engineering's required sophomore biological thermodynamics subject and assist in creating a new immunoengineering elective. Irmgard Bischofberger will join the faculty in the Department of Mechanical Engineering in January 2016. She received her BS, MS, and PhD in physics from the University of Fribourg in Switzerland, and is currently a postdoc at the University of Chicago. Bischofberger received a Kadanoff-Rice postdoctoral fellowship at the University of Chicago, as well as a Swiss National Science Foundation postdoctoral fellowship, and was a poster prize winner for the APS Gallery of Fluid Motion in 2012. She works in the areas of fluid dynamics and soft-matter physics, with a focus on the formation of patterns from instabilities in fluid and technological systems. In her graduate work, she studied the phase behavior and solvation properties of thermosensitive polymers. As a postdoc, she has discovered “proportional growth” — a new growth pattern that had not been previously observed despite its common occurrence in biological systems. Guy Bresler, the Bonnie and Marty (1964) Career Development Professor, joined the faculty in July in both the Department of Electrical Engineering and Computer Science and the Institute for Data, Systems, and Society; he will also be a member of the Laboratory for Information and Decision Systems. Bresler received his BS in electrical and computer engineering and an MS in mathematics from the University of Illinois at Urbana-Champaign. He received his PhD from the Department of Electrical Engineering and Computer Science at the University of California at Berkeley, and was subsequently a postdoc at MIT. He is the recipient of a National Science Foundation graduate research fellowship, a Vodafone graduate fellowship, the Barry M. Goldwater scholarship, and the Roberto Padovani Award from Qualcomm. Bresler’s research interests are at the interface of statistics, computation, and information theory. A current focus is on understanding the relationship between combinatorial structure and computational tractability of high-dimensional inference in graphical and statistical models. Betar Gallant will join the MIT faculty in January 2016 as an assistant professor of mechanical engineering. Gallant completed her BS, MS, and PhD in mechanical engineering at MIT. During her graduate studies with Professor Yang Shao-Horn, she was an National Science Foundation graduate research fellow, an MIT Martin Family Fellow and an MIT Energy Initiative Fellow. Gallant was a Kavli Nanoscience Institute Prize postdoctoral fellow at Caltech, where her research focused on tuning mechanical properties via surface chemistry control in Si-polymer structures for solar fuels applications. She will develop materials and devices for energy and environmental cleanup applications including greenhouse gas and pollutant capture and conversion, which will be informed by the understanding of chemical and electrochemical reaction pathways. She plans to utilize nanoscale insights into heat and mass transfer and energy conversion to bridge molecular control of processes with scalable environmental technologies. Ming Guo joined the faculty in the Department of Mechanical Engineering in August. He received a BE and an ME in engineering mechanics from Tsinghua University in China, and an MS and PhD from Harvard University. His doctoral research investigated the mechanical and dynamic properties of living mammalian cells, with an emphasis on intracellular mechanics and forces, the mechanics of cytoskeletal polymers, the equation of state of living cells, and the effect of cell volume and intracellular crowding on cell mechanics and gene expression. Guo discovered that there is a direct relationship between cell stiffness and volume. By varying the cell volume through a number of different techniques, he showed that the volume of cells is a much better predictor of their stiffness than any other cue, and he developed a method to measure the mechanical properties and overall motor forces inside living cells by monitoring the fluctuation of microbeads inside the cells and delineating the timescales under which the contribution of active cellular processes could be distinguished from passive mechanical properties. Jeehwan Kim joined the Department of Mechanical Engineering faculty in September. He received his BS from Hongik University in South Korea, his MS from Seoul National University, and his PhD from the University of California at Los Angeles in 2008, all in materials science. Since 2008, Kim has been a research staff member at IBM’s T.J. Watson Research Center, conducting research in photovoltaics, 2-D materials, graphene, and advanced complementary metal-oxide semiconductor (CMOS) devices. He has been named a master inventor at IBM for his prolific creativity, with over 100 patent filings in five years. Kim’s breakthrough contributions include: demonstration of peeling of large-area single-crystal graphene grown from a SiC substrate, enabling reuse of the expensive substrate; successful growth of GaN on graphene, with 25 percent lattice mismatch, demonstrating that GaN films grown from the process function well as LEDs and pointing to a new principle for growing common semiconductors for flexible electronics; and achieving high efficiency in silicon/polymer tandem solar cells and 3-D solar cells. Luqiao Liu joined MIT as an assistant professor in electrical engineering and computer science in September. He received his BS in physics from Peking University in China and his PhD in applied physics from Cornell University. He received a graduate student fellowship and the Aravind V. Subramanium T.L. Memorial Award from Cornell. Before joining MIT, Liu worked as a research staff member at IBM’s T.J. Watson Research Center. His research is in the field of spin electronics. In particular, he focuses on nanoscale materials and devices for spin logic, non-volatile memory, and microwave applications. Liu is also a recipient of the Patent Application Achievement Award from IBM. Nuno Loureiro will join the Department of Nuclear Science and Engineering faculty as an assistant professor in January 2016; he will work with the theory group of the MIT Plasma Science and Fusion Center. He earned a degree in physics engineering from Instituto Superior Técnico (IST) in Portugal, and a PhD in plasma physics from Imperial College for analytical and numerical work on the tearing instability. Loureiro held a postdoctoral position at the Princeton Plasma Physics Laboratory, a fusion research fellowship at the Culham Center for Fusion Energy in the UK, and was awarded an advanced fellowship from the Portuguese Science and Technology Foundation to work at the Institute for Plasmas and Nuclear Fusion (IPFN) at IST Lisbon. In 2012 Loureiro was appointed head of the Theory and Modeling Group at IPFN and served as an invited associate professor at the physics department of IST. His research interests cover a broad range of plasma-physics theoretical problems, including magnetic reconnection, the generation and amplification of magnetic fields, turbulent transport in magnetized plasmas, and fast-particle-driven instabilities in fusion plasmas. Loureiro is the 2015 recipient of the American Physical Society’s Thomas H. Stix Award for outstanding early career contributions to plasma physics. Robert Macfarlane, the AMAX Career Development Professor in Materials Engineering, joined the faculty as an assistant professor in the Department of Materials Science and Engineering this past summer. He earned his BA in biochemistry at Willamette University and his PhD in chemistry at Northwestern University. Macfarlane’s research is focused on developing a set of design principles for synthesizing new inorganic/organic composite materials, where nanoscale structure can be manipulated to tune the emergent physical properties of a bulk material. These structures have the potential to significantly impact energy-related research via light manipulation (e.g. photonic band gaps or plasmonic metamaterials), electronic device fabrication (e.g. semiconducting substrates or data storage devices), and environmental and medical research (e.g. hydrogels for sustained drug delivery). Karthish Manthiram will join the faculty as an assistant professor in the Department of Chemical Engineering in 2017. Currently a postdoc at Caltech, he received a bachelor’s degree in chemical engineering from Stanford University and his PhD in chemical engineering from the University of California at Berkeley. He received the Dan Cubicciotti Award of the Electrochemical Society, a Department of Energy Office of Science graduate fellowship, a Tau Beta Pi fellowship, the Mason and Marsden prize, a Dow Excellence in Teaching Award, and the Berkeley Department of Chemical and Biomolecular Engineering teaching award. As a graduate student, Manthiram developed transition-metal oxide hosts for redox-tunable plasmons and nanoparticle electrocatalysts for reducing carbon dioxide. His research program at MIT will focus on the molecular engineering of electrocatalysts for the synthesis of organic molecules, including pharmaceuticals, fuels, and commodity chemicals, using renewable feedstocks. Benedetto Marelli will join the faculty as an assistant professor in the Department of Civil and Environmental Engineering in November. He received a BE and an MS in biomedical engineering from Polytechnic University of Milan and pursued his doctoral studies in materials science and engineering at McGill University. His dissertation focused on the biomineralization of tissue-equivalent collagenous constructs and their use as rapidly-implantable osteogenic materials. As a postdoc at Tufts University, Marelli worked on the self-assembly and polymorphism of structural proteins, particularly silk fibroin. Marelli’s research at MIT will be in the area of structural biopolymers, biomineralization and self-assembly, mechanical and optoelectronic properties of natural polymers, biocomposites, additive manufacturing, and emerging technologies. By combining basic material principles with advanced fabrication techniques and additive manufacturing, he has developed new strategies to drive the self-assembly of structural biopolymers in advanced materials with unconventional forms and functions such as inkjet prints of silk fibroin that change in color in the presence of bacteria or flexible keratin-made photonic crystals. Using biofabrication strategies, his group will design bio-inspired materials that act at the biotic/abiotic interface to reduce or mitigate environmental impact. Admir Masic joined the faculty as an assistant professor in the Department of Civil and Environmental Engineering in September. He received an MS in inorganic chemistry and a PhD in physical chemistry from the University of Torino in Italy. He was a postdoc at the Max Planck Institute of Colloids and Interfaces, investigating the structural and mechanical properties of biological materials and received the Young Investigator Award from the German Research Foundation focusing on effects of water on the mechanical properties of collagen-based materials. During his PhD, Masic developed advanced characterization methodologies for the non-invasive study of deterioration pathways in ancient manuscripts, including quantifying the extent of collagen degradation in Dead Sea Scrolls. His research focus is on the development of novel, high-performance, in situ, and multi-scale characterization techniques that are able to overcome current research bottlenecks in the investigation of complex hierarchically organized materials. His work is geared towards investigating the structural and mechanical properties of biological materials, including the study of ageing and pathological processes. He is interested in the degradation and preservation of cultural artifacts, historical buildings, and civil infrastructure. Julia Ortony, the John Chipman Career Development Professor, will join the Department of Materials Science and Engineering faculty in January 2016. She earned her BS in chemistry at the University of Minnesota and her PhD in materials chemistry at the University of California at Santa Barbara. Ortony’s research interests are in two main areas: the design and optimization of soft materials with nanoscale structure for important new technologies, and the development of advanced instrumentation for measuring conformational and water dynamics analogous to molecular dynamics simulations. By combining these thrusts, technologies ranging from biomedical therapies to energy materials will be explored with special consideration paid to molecular motion. Ellen Roche will join the Department of Mechanical Engineering faculty in summer 2016, following postdoctoral training at the University of Galway; she will also be a core member of the Institute for Medical Engineering and Science. She received her BE in biomedical engineering from the National University of Ireland in Galway, and her MS in bioengineering from Trinity College in Dublin. Between these degrees, she spent five years working on medical device design for Mednova Ltd., Abbot Vascular, and Medtronic. She later received her PhD in bioengineering from Harvard University. Roche’s awards include the American Heart Association Pre-doctoral fellowship, a Fulbright international science and technology award, the Harvard Pierce fellowship for outstanding graduates, the Medtronic AVE Award, and the Ryan Hanley Award. She specializes in the design of cardiac medical devices. At Harvard, she performed research on the design, modeling, experimentation, and pre-clinical evaluation of a novel soft-robotic device that helps patients with heart failure. Her invention, the Harvard Ventricular Assist Device (HarVAD), is a soft-robotic sleeve device that goes around the heart, squeezing and twisting it to maintain the heart’s functionality. The device has no contact with blood, dramatically reducing the risks of infection or blood clotting as compared to current devices. Additionally, she worked on incorporation of biomaterials into the device to deliver regenerative therapy directly to the heart. Roche’s device, which has been validated in testing with animals, could restore normal heart function in heart failure patients. Serguei Saavedra will join the faculty in January 2016 as an assistant professor in the Department of Civil and Environmental Engineering. He received a PhD in engineering science from Oxford University. For the past four years he has been working as a postdoc at the Department of Integrative Ecology at Doñana Biological Station in Spain, at the Department of Environmental Systems Science at ETH Zurich, and at the Institute of Evolutionary Biology and Environmental Studies at the University of Zurich. Saavedra works in the area of community ecology, developing quantitative methods to understand the factors responsible for sustaining large species interaction networks. His work has revealed significant connections between the structure of these networks and the range of conditions leading to species coexistence. He has established foundations to study the response of these networks to the effects of environmental change. Saavedra’s work also has applications to sustainability in large socioeconomic systems. Justin Solomon will join the faculty as an assistant professor in the Department of Electrical Engineering and Computer Science by July 2016. He is currently a National Science Foundation mathematical sciences postdoc in applied math at Princeton University. He earned his MS and PhD in computer science from Stanford University, where he also earned a BS in mathematics and computer science. Solomon is a past recipient of the Hertz Foundation fellowship, a National Science Foundation graduate fellowship, and the National Defense science and engineering graduate fellowship. His research focuses on geometric problems appearing in shape analysis, optimization, and data processing, with application in computer graphics, medical imaging, machine learning, and other areas. He taught classes on numerical analysis, computational differential geometry, and computer science at Stanford. His textbook, "Numerical Algorithms," was released in 2015 (CRC Press). Cem Tasan will join the faculty in the Department of Materials Science and Engineering in January 2016. He holds a BS and MS from Middle East Technical University in Turkey, both in metallurgical and materials engineering, and a PhD from Eindhoven University of Technology in the Netherlands in mechanical engineering. Tasan was previously a group leader in adaptive structural materials at the Max Planck Institute for Iron Research, where he had also been a postdoc working on microplasticity at phase boundaries of multi-phase steels. He explores the boundaries of physical metallurgy, solid mechanics, and analytical microscopy in order to provide structural materials solutions to environmental challenges. His interests in micro-mechanically guided design of damage-resistant alloys and simulation-guided design of healable alloys have many applications for problems in energy and the environment. Caroline Uhler joined the Department of Electrical Engineering and Computer Science and the Institute for Data, Systems, and Society as an assistant professor in October. She holds an MS in mathematics, a BS in biology, and an MEd in high school mathematics education from the University of Zurich. She obtained her PhD in statistics, with a designated emphasis in computational and genomic biology, from the University of California at Berkeley. She is an elected member of the International Statistical Institute and received a START Award from the Austrian Science Fund. After a semester as a research fellow in the program on “Theoretical Foundations of Big Data Analysis” at the Simons Institute at Berkeley and postdoctoral positions at the Institute of Mathematics and its Applications at the University of Minnesota, and at ETH Zurich, she joined the Institute of Science and Technology Austria as an assistant professor. Her research focuses on mathematical statistics, in particular on graphical models and the use of algebraic and geometric methods in statistics, and its applications to biology.

Shin Y.S.,Kavli Nanoscience Institute | Remacle F.,University of Liège | Fan R.,Yale University | Hwang K.,Kavli Nanoscience Institute | And 6 more authors.
Biophysical Journal | Year: 2011

Protein signaling networks among cells play critical roles in a host of pathophysiological processes, from inflammation to tumorigenesis. We report on an approach that integrates microfluidic cell handling, in situ protein secretion profiling, and information theory to determine an extracellular protein-signaling network and the role of perturbations. We assayed 12 proteins secreted from human macrophages that were subjected to lipopolysaccharide challenge, which emulates the macrophage-based innate immune responses against Gram-negative bacteria. We characterize the fluctuations in protein secretion of single cells, and of small cell colonies (n = 2, 3,...), as a function of colony size. Measuring the fluctuations permits a validation of the conditions required for the application of a quantitative version of the Le Chatelier's principle, as derived using information theory. This principle provides a quantitative prediction of the role of perturbations and allows a characterization of a protein-protein interaction network. © 2011 by the Biophysical Society.

Henry M.D.,California Institute of Technology | Henry M.D.,Kavli Nanoscience Institute | Shearn M.J.,California Institute of Technology | Shearn M.J.,Kavli Nanoscience Institute | And 4 more authors.
Nanotechnology | Year: 2010

By using a dry etch chemistry which relies on the highly preferential etching of silicon, over that of gallium (Ga), we show resist-free fabrication of precision, high aspect ratio nanostructures and microstructures in silicon using a focused ion beam (FIB) and an inductively coupled plasma reactive ion etcher (ICP-RIE). Silicon etch masks are patterned via Ga+ ion implantation in a FIB and then anisotropically etched in an ICP-RIE using fluorinated etch chemistries. We determine the critical areal density of the implanted Ga layer in silicon required to achieve a desired etch depth for both a Pseudo Bosch (SF6/C4F8) and cryogenic fluorine (SF6/O2) silicon etching. High fidelity nanoscale structures down to 30nm and high aspect ratio structures of 17:1 are demonstrated. Since etch masks may be patterned on uneven surfaces, we utilize this lithography to create multilayer structures in silicon. The linear selectivity versus implanted Ga density enables grayscale lithography. Limits on the ultimate resolution and selectivity of Ga lithography are also discussed. © 2010 IOP Publishing Ltd.

Berweger S.,U.S. National Institute of Standards and Technology | Weber J.C.,U.S. National Institute of Standards and Technology | John J.,California Institute of Technology | Velazquez J.M.,Kavli Nanoscience Institute | And 11 more authors.
Nano Letters | Year: 2015

Optimizing new generations of two-dimensional devices based on van der Waals materials will require techniques capable of measuring variations in electronic properties in situ and with nanometer spatial resolution. We perform scanning microwave microscopy (SMM) imaging of single layers of MoS2 and n- and p-doped WSe2. By controlling the sample charge carrier concentration through the applied tip bias, we are able to reversibly control and optimize the SMM contrast to image variations in electronic structure and the localized effects of surface contaminants. By further performing tip bias-dependent point spectroscopy together with finite element simulations, we distinguish the effects of the quantum capacitance and determine the local dominant charge carrier species and dopant concentration. These results underscore the capability of SMM for the study of 2D materials to image, identify, and study electronic defects. © 2015 American Chemical Society.

Heath J.,Kavli Nanoscience Institute
Optics InfoBase Conference Papers | Year: 2011

There exist multiple classes of energy conversion materials and devices - including electrochemical cells, photovoltaics, and thermoelectrics. In all systems, heat dissipation can be a limiting factor in determining overall efficiency. In this talk, I will discuss thermoelectric materials (TEs), which are materials that interconvert thermal gradients and electric fields for power generation or for refrigeration. TEs find only niche applications because of their limited efficiency, which is measured by the dimensionless parameter ZT=S2sσ/κ. Here S is the Seebeck coefficient, or thermoelectric power (measured in Volts K-1), and σ and κ are the electrical and thermal conductivities, respectively. Maximizing ZT is challenging because optimizing one physical parameter often adversely affects another - for example, the Weidemann-Franz law limits the ratio of σ/κ to be a constant for metallic systems. Several groups have achieved significant improvements in ZT through multi-component nanostructured TEs (5-7), such as Bi2Te3/Sb2Te3 thin film superlattices, or embedded PbSeTe quantum dot superlattices. We recently reported efficient TE performance from the single component system of silicon nanowires (SiNWs) for cross-sectional areas of 10nm × 20nm and 20nm × 20nm. By varying the nanowire size and impurity doping levels, ZT values representing an approximately 100-fold improvement over bulk Si are achieved over a broad temperature range, including a ZT ~ 1 at 200K. Independent measurements of S, s, and σ, combined with theory, indicate that the improved efficiency originates from phonon effects. For the smallest width nanowires, the thermal conductivity was observed to be below the Slack-limit for silicon, implying that fundamentally new physics is being observed in these materials. In addition, phonon drag appears to make important, positive contributions to the nanowires thermopower. These results are expected to apply to other classes of semiconductor nanomaterials, as well as nanostructured bulk materials, and I will discuss some of our recent work that is aimed toward exploring these ideas. Finally, from a practical point of view, thermoelectric or thermocooling applications require both p- and n-type conductors. For Si NWs, both p- and n-type NWs can exhibit a high thermoelectric efficiency, although there are differences between the two materials. © 2008 OSA.

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