Umberto Ravaioli - US grants

It is usual to define the electronic properties of microstructure of solid state devices in relation to the degree of freedom of mobile charge carriers, i. e. simple layered structures are referred as 2- dimensional (2D) systems, double confined structures or quantum wires and quantum balls are defined as 1-D and 0-D systems respectively. In general, these systems are referred to as Ultra-Low Dimensional Systems (ULDS). Current technology is based on the 2-D systems. However, advances in high resolution fine line lithography and crystal growth techniques indicate that microstructure on the scale of quantum wires and balls may be possible. The potential use of the artificial materials with 1-D or 0-D microstructures for computer memory and ultra-high device integration is considerable. Efficient device simulation algorithms are necessary for modeling the properties of the microstructure and indispensable to the introduction of this next generation of VLSI technology. This research project addresses the development of a robust, fast, and flexible algorithm to determine the relevant physical and microstructure parameters for optimal design and performance of devices of the Ultra-low Dimensional Systems. A team of young investigators composed of device physicists, numerical analyst, and computer scientist will be formed as an interdisciplinary group.

A Center for Computational Electronics (CCE) will be formed at the University of Illinois at Urbana-Champaign and located in the Beckman Institute. The Center shall promote effective use of large computational resources and shared experiences for simulations including device modeling, process simulations and particle Monte Carlo codes, which includes physical details as electronic band-structure and scattering mechanisms. It will provide a forum for the exchange of ideas and technical assistance for matters involving device modeling using supercomputers. The Center will not provide directives for research goals nor will it interfere with the activities of any research group or individual. However, it will promote collaboration between investigators with similar interests and make available basic computer codes. The standardization of material parameters is the second goal of this Center. The Center shall collect, organize, and format the data for the device simulation community and make them available in cooperation with the Center for Compound Semiconductor Microelectronics (NSF-ERC). The Center will support graduate students in a cross-disciplinary environment with special emphasis on algorithm development for solid-state device modeling. Futhermore, the Center will participate in the on-going Visitor's program of the Beckman Institute and National Center for Supercomputing Application. The Center will act as an international contact with research groups overseas, to organize periodic workshops, to publish a newsletter, and to establish and maintain a strong communication network for the device simulation researchers.

This is a renewal support of NCCE, the National Center for Computational Electronics, previously supported under NSF grant ECS-8809023. There are three major components: research, education and computational services. Research focus is electron transport in solid-state semiconductors. The specific used in Monte Carlo Simulation for the solution to the Boltzman Transport Equation; up-grade standard drift- diffusion simulators by including full band-structure in a Monte Carlo add-on package; higher-order moment closure (hydrodynamic) models for parallel implementation; include lattice temperature effects for high current/voltage regimes; coupling of device performance to circuit and thermal boundary conditions (mixed-mode simulation). Educational activities includes the support of post-doctoral visitors at the Beckman Institute and NCSA, the National Center for Supercomputing Applications, regular workshop and tutorials for graduate students, and developing stronger ties to the SRC Technology Transfer Courses (TTC's). Creation of a board environment for the students in device modeling which will include not only electrical engineering but also applied mathematicians, aeronautical and mechanical engineers, computer scientists all of whom have similar computational difficulties. NCCE will continue to be the node for computational resources for device modeling community. It will coordinate with NCSA for block time on a mix of platforms, vector, massively parallel, high-eng graphics, etc. Furthermore, NCCE will continue to provide software consultation to the community on improving code efficiency on the supercomputers. Finally, NCCE will continue the development and expansion of cross-disciplinary groups and collaboration between academic institutions and industrial laboratories.

The International Workshop on Computational Electronics will be held at the Beckman Institute of the University of Illinois at Urbana-Champaign on May 28-29, 1992. The workshop will cover all aspects of advanced simulation of electronic transport in semiconductors and semiconductor devices, particularly those which use large computational resources. Topics will include: 2-D and 3-D standard simulations (drift- diffusion, hydrodynamic equations), Monte Carlo device simulations, and Approaches to quantum transport. The workshop is intended to be an international forum for the discussion on the current trends and the future directions of computational electronics. A significant number of invited papers presented by speakers from major universities and laboratories in Europe an Asia will be included. Plenary sessions will be followed by poster presentations from US groups, to stimulate and contribute to overall discussion. The emphasis of the contributions will be on interdisciplinary aspects of Computational Electronics, encompassing Applied Physics, Engineering and Applied Mathematics. Active participation of graduate students, including student poster papers, will be strongly encouraged. The results of the workshop will be disseminated in the form of proceedings. In the past Kluwer Academic Publishers has efficiently handled the printing of the proceedings which then where distributed to the participants within a few months after the meeting. Attempt to have similar arrangements with a publisher to be determined by university procedures will be made.

9509751 Kerkhoven This research will focus on the development of numerical simulation approaches suitable for the analysis and design of nanostructures. The investigations will address quantum wire and quantum dot structures, with the goal to develop comprehensive physical and numerical models that can explain the results of measurements on experimental nanostructures, in a wide range of temperatures. The work will also consider new structures based on modification of existing silicon technology scaled into the nanometer range. A major effort will be in the area of 3-D models, to extend previous work to even more realistic situations, and improve the ability to treat extremely large numerical problems efficiently. Among other problems of interest is the development of direct numerical approaches for the characterization of atomic cluster, like the writing tip of a Scanning Tunneling Microscope (STM) in proximity of the surface of a nanostructure and 3-D solvers for the optical behavior of microstructure semiconductor lasers with surface emitting topology. For both applications, the unique approaches that were developed earlier for the solution of large sparse eigenvalue problems for semiconductor structures, will be adapted and extended.

9802730
Hess
A Distributed Center for Advanced Electronics Simulation called DesCArtES will be established to address the needs of predictive physical models and computational tools for future generations of nanoelectronic and optoelectronic devices. The efforts will focus on several key research themes of highest priority, through the formation of a strong collaborative team linking four of the leading academic groups in Computational Electronics: the University of Illinois at Urbana-Champaign (acting as lead institution), Stanford University, Purdue University and Arizona State University. These groups have each their own strengths, and at the same time sufficient overlap of interests and a track record of collaboration, so that joint research efforts on the proposed themes can be effectively pursued.

The research themes include:

a) Continuum and Semi-Classical Simulation of Devices;
b) Optoelectronics Simulation;
c) Atomic-Scale Process Modeling for Nanoelectronics;
d) Quantum Transport in Nanoscale Devices.

The goals of this research consortium impact applications on a very large computational scale. While most of the development and testing can be conducted on typical workstations, realistic calculations, particularly in 3-D, will require considerable use of multiprocessor supercomputers. DesCArtES will have key interactions with many industrial laboratories, e.g. the National Center for Supercomputing Applications (NCSA) in Illinois, the Jet Propulsion Laboratory (JPL) and NASA Ames Research Center in California. Through the close relationship with these centers, the consortium will gain access to the high performance computational infrastructure necessary for the research efforts proposed. The collaboration with JPL and NASA also emphasizes goals that are new and in many ways complementary to the goals usually pursued in the industrial collaborations of this partnership. From the variety of collaborations as well as the interdisciplinary emphasis of some of the proposed research, the center will derive a well-rounded and creative perspective of new and important applications in Computational Electronics, thus creating the necessary environment to pursue successfully the proposed research themes.
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In recent years, there has been continuous miniaturization of microelectronic devices and circuits. Typical channel lengths in electronic devices, currently at 180 nm, are expected to fall to 70 nm by the year 2008 and new devices in the 3-40 nm range have already been fabricated in research laboratories. Despite drops in supply voltage, power dissipation in emerging transistor designs is expected to reach 160 W per chip by the end of this decade. Emerging technologies, such as silicon-on-insulator (SOI) FETs, face severely increased self-heating because of the thermally insulating properties of the chip design, and thermally-induced failures are expected to increase. This proposal seeks to explore computationally the coupled electro-thermal behavior of microelectronic devices. Though channel scales ranging from 10-180 nm will be studied to build a complete picture, the emphasis of the proposal is on understanding thermal behavior at the smaller scales. The proposed work will explore the influence of important micro-scale thermal phenomena such as phonon boundary scattering, small heat-source effects due to ballistic phonon transport in the hot spot, and phonon confinement effects, which substantially alter phonon dispersion curves and decrease phonon group velocities. Models based on both molecular dynamics as well as the Boltzmann transport equation will be developed, with electron-phonon interaction being computed by the full-band Monte Carlo simulator MOCA. Finally, these phonon transport and heat generation models will be coupled to Fourier conduction models for other device structures to understand the thermal behavior of emerging ultra-scaled devices. This proposal was submitted in response to NSF 02-168 Information Technology Research, in the "Small" category. The award has been funded by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division.

This project will create InvertNet, an on-line virtual museum comprising >50 million insect and related arthropod specimens housed at 22 Midwestern institutions, focusing on the research theme of effects of land use changes on the biota of the Great Lakes and upper Mississippi River drainage basins. These collections document 160 years of environmental change and are an invaluable and irreplaceable resource but, at present, are largely inaccessible to scientists and the general public. Most previous efforts to capture and disseminate invertebrate collection data have focused on label data alone. InvertNet will use advanced digitization and networking technologies to capture and display 2D and 3D images of specimens and labels, and incorporate them into a searchable database. These new techniques should reduce the cost of digitizing insect specimens substantially.

By allowing users to find and view detailed images of specimens of particular species and their associated data labels, InvertNet will provide universal access to collections previously restricted to researchers. It will include links to the popular BugGuide.net insect identification website and to other biodiversity data portals used by researchers, educators, and the general public. This will facilitate and support many aspects of biological research and education, including species discovery and identification, pest management, ecology and biogeography. InvertNet will serve as a model, applicable to other kinds of biological collections, for the use of efficient, computer-assisted procedures to increase the speed and accuracy of collection data capture. This award is made as part of the National Resource for Digitization of Biological Collections through the Advancing Digitization of Biological Collections program and all data resulting from this award will be available through the national resource.

This proposal aims to establish the nanoBIO node of the reconfigured Network for Computational Nanotechnology (NCN) at Illinois. The proposed node will create extensive online resources with the purpose to position the NCN Cyber Platform as the focal point for collaborative interactions of a diverse computational and experimental nanoBIO community. Although the proposal covers a comprehensive range of activities, the overriding goal is to organize the node as the first step towards a nanoBIO eco-system, by completing a set of four high-priority technical objectives: 1) development of critical online computational tools as essential building blocks for nanoBIO device simulation and experimental validation; 2) development of workflows linking simulations at different scales and leading to an extensible online environment for nanoBIO device design; 3) creation of transformative educational resources for biology, infusing modern nanoscience concepts via interactive simulation and visualization; 4) demonstration of a new paradigm for information sharing and knowledge discovery, with innovative scalable databases for searchable collections of computational and experimental nanoBIO datasets.

To optimize the available resources, the nanoBIO node planning strategy has been to organize a network within the network, reaching out to key bioengineering and life science groups on campus, followed by forging partnerships with related IGERT programs, multi-university centers, and industrial collaborations to create a national fabric of interactions. A key partnership has also been established with the University of California-Merced to capitalize on existing collaborations in research and education and to leverage their computational biology based undergraduate programs. A cooperative effort to design engaging material between UC-Merced and the School of Molecular and Cellular Biology at UIUC will drive the NCN to become a revolutionary biology classroom environment that integrates research with education and stimulates undergraduates to develop interdisciplinary thinking, mirroring the IGERT mission. These rich online resources will also facilitate the access and understanding of nanoBIO concepts in K-12 education. To address the focus on devices and systems, the nanoBIO node will engage laboratories at UIUC with cutting-edge expertise in computational biology, bio-device fabrication and information technology, these laboratories include: the Beckman Institute, the Micro & Nanotechnology Laboratory, the Institute for Genomic Biology, and the National Center for Supercomputing Applications. UC Merced will also play an important role in creating and directing qualified underrepresented students towards pursuing careers in nanoBIO disciplines.

Intellectual Merit: An immense challenge faced by designers and manufacturers of nanoBIO devices and systems is the lack of integrated computational and training tools addressing the multiple length scales and the physical complexity needed to bridge biology with engineering. The establishment of a dedicated nanoBIO node of NCN provides an exciting opportunity to address this and formulates a comprehensive plan with nation-wide reach to support nanoBIO research and education. The vision for this NCN nanoBIO node is to form an active community that accelerates the creation of multidisciplinary computational tools and transformative training materials in nanoscience and nanoengineering for the design of novel nanoBIO devices and systems that will have a positive influence on our quality of life and environment. This effort will have a major impact on the development of human resources by facilitating training. The availability of online tools will also benefit industry, particularly small businesses and nanoBIO start-ups needing access to specialized resources.

Broader Impact: The urgency to contain health care costs and improve services, the imperatives to provide safe and plentiful food supplies, and the need for efficient bio-fuel production as part of a sustainable energy strategy all point to biology as the pivotal science of the future, and nanotechnology as the enabler. The ultimate goal of the nanoBIO node is to create resources for the discovery of devices suitable for nanoBIO applications, and to train the next generation of leaders who will translate nanoBIO technologies from research to the marketplace. These are crucial steps toward sustained transformation and revitalization of the health care industry, with broad potential impact on the creation of new high-tech jobs in an important manufacturing sector in the US. A new breed of scientists and engineers, with expertise across multiple physical and life science disciplines, is needed to sustain this vision. The node aspires to be the catalysts for truly innovative interdisciplinary education opportunities, putting forward an exciting educational plan which lays the foundations for a multi-faceted and integrated K-to-PhD pathway.

TECHNICAL SUMMARY:
The purpose of this project is to establish an REU site in the area of nanotechnology at the University of Illinois at Urbana-Champaign with support from the NSF Division of Engineering Education and Centers. Students participating in the program will be embedded in a rich environment providing integrated research and educational experiences in a wide range of nanotechnology areas, from nanoelectronics to nanophotonics, nanomaterials and nanobiotechnology. The ultimate goal is to solidify the students' interest in graduate research and education and contribute to the diversity of the national workforce pipeline, through experiences designed not only to expose the participants to cutting edge and interdisciplinary technical aspects of nanotechnology but also to infuse critical thinking, leadership, communication, team-building, and ethics training. Additionally, the assessment and evaluation activities will be embedded throughout the program to determine the effectiveness of the various training components and students will be tracked longitudinally to determine the impact of the program on individuals, institutions and the field as a whole. The REU program will engage ten domestic undergraduate students (rising sophomores to rising seniors) in a ten week summer curriculum on the University of Illinois campus each year, combining a range of common activities (orientations, seminars and workshops) with personalized experiences in the laboratories affiliated with this effort. Students will spend at least 30 hours per week doing research with faculty and graduate student mentors, and will be fully engaged in normal laboratory activities attending group meeting performing literature reviews, running experiments and simulations and keeping laboratory notebooks. Research topics will be assigned matching the interest of the participants and representative projects may include: design of plasmonic nanoparticles for live cell sensing; DNA sequencing through solid state nanopores; design and fabrication of nano-porous conformal films for photonic applications; simulation of charge transport in nanosystems. Capstone of the experience will be participation, during the tenth week of the program, in the campus-wide Illinois Summer Research Symposium where students will present the results of their work.


NON-TECHNICAL SUMMARY:
Nanotechnology is a broad interdisciplinary field which holds the promise to address grand challenge problems, leading to the improvement of quality of life and providing new opportunities for economic growth. Progress in nanotechnology needs the availability of a qualified workforce with technical knowledge and interdisciplinary skills. The purpose of this project is to establish an REU site in the area of nanotechnology at the University of Illinois at Urbana-Champaign with support from the NSF Division of Engineering Education and Centers. The program will engage each summer a diverse group of ten domestic undergraduate students recruited around the country for a ten week summer curriculum which combines a range of common professional development activities with personalized experiences in research laboratories. The goal is to provide, through an early experience in exciting cutting-edge areas of nanoscience and engineering, the motivation to choose a professional path in research. Through hands-on activities embedded in leading nanotechnology laboratories, students will have the opportunity to work next to faculty and graduate student mentors, contributing to the development of new materials that could enable further miniaturization of electronics chips or fabricating novel sensors for diagnostics and therapeutics in personalized medicine.