1984 — 1990 |
Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Experimental Transport Studies of Low Dimensional Conductors @ University of California-Berkeley |
0.915 |
1984 — 1989 |
Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Presidential Young Investigator Award @ University of California-Berkeley |
0.915 |
1991 — 1994 |
Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Electronic and Mechanical Properties of Low Dimensional Conductors @ University of California-Berkeley
This research program plans to study the linear and nonlinear dynamics and elastic properties of low dimensional conductors supporting charge density wave (CDW) and spin density wave (SDW) condensates. The CDW systems include, among others nyobium selenides and sulfides, tantalum sulfide, and several alkali molybdates, while the SDW systems include chromium, uranium- ruthenium silicide and a one-dimensional organic chain. A variety of electrical conductivity and noise measurements will be performed over a wide range of frequency, magnetic field, pressure, and sample spatial extent to determine the internal mode dynamics, metastable state structure, and the role of electron-electron correlations. The properties of the dynamic SPW condensates will be explored. Elastic measurements of CDW or SDW materials in the presence of ac + dc electric fields and other perturbations will help establish internal mode deformations and lattice couplings. Nonlinear dynamics (chaos) studies will help reveal the number of active degrees of freedom in CDW transport and the role of amplitude dynamics.
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0.915 |
1994 — 1997 |
Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Fullerene-Based Conductors and Superconductors @ University of California-Berkeley
9404755 Zettl The electronic and thermal properties of fullerene-based materials, pure and alkali-doped carbon-60 and carbon-70, will be examined using various transport, structural, mechanical and tunneling measurements. Electron phonon coupling in the normal and superconducting states will be investigated through transport, tunneling, and isotopic replacement on both the alkali and carbon sites. Carrier concentration and possible correlation-induced localization effects will be explored using Hall measurements. High pressures will be applied to probe transport properties and superconductivity as a function of lattice constants and variable density of states. % % % % The properties of novel carbon materials formed from so called fullerenes will be explored using a variety of probes, including transport of electricity and heat through the materials at atmospheric and high pressures. The mechanical strength of the structures will be determined using elasticity measurements. Atoms of different masses (different isotopes) will be introduced in the structures to help understand the interactions between the electrons and the vibrations of the atoms. This interaction may be responsible for some of the materials being superconducting (zero electrical resistance). ***
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0.915 |
1995 — 1998 |
Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Development of a Low Temperature, High-Field, Ultra-High Vacuum Scanning Tunneling Microscope @ University of California-Berkeley
9501156 Zettl The invention of the scanning tunneling microscope (STM) has had tremendous impact on condensed matter physics and other disciplines. Although the STM was used originally only as a high-resolution, low-speed electronic imaging device, recent generation STM's have seen a wider variety of applications, including the picosecond resolution of tunneling and excitation processes and the control of nonlinear optical processes such as frequency mixing and harmonic generation. One long-time goal has been the ability to use the STM to construct and characterize new nanoscale structures, formed atom-by-atom or molecule-by-molecule. Although elusive, this capability promises the investigation of quantum size effects, atomic interactions, and novel electronic circuit elements. This award will find the construction of the next-generation STM, designed specifically to assemble and characterize nanoscale structures with unusual electronic properties. This machine will uniquely combine materials synthesis, manipulation, and high-resolution characterization capabilities, including operation at low temperature in ultrahigh vacuum (UHV) under high magnetic field, with atomic resolution and with unsurpassed high-speed data processing. Several outstanding problems in condensed matter physics necessitate such a machine and provide the initial motivation for its construction: (1) studies of metallic and superconducting clusters; (2) spectroscopy of one-and two-dimensional materials; and (3) fabrication of networks and quantum confined structures. ***
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0.915 |
1998 — 2001 |
Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Transport Studies of Novel Electronic and Magnetic Materials @ University of California-Berkeley
w:\awards\awards96\*.doc 9801738 Zettl This experimental research project focuses on the electronic transport properties of novel collossal magnetoresistance (CMR) manganite perovskite materials. Emphasis is on the electronic, thermal and magnetic properties studied by means of transport annd magnetic measurements. Much of the study will focus on the use of high pressures to which the CMR effect is particularly sensitive. Both teflon-seal and diamond anvil cells will be employed. Isotopic substitution will also be performed, independently and in conjunction with the pressure studies. The aim of the research is to clarify the fundamental interactions, such as polaron formation and dynamics, responsible for the unusual transport and magnetotransport behaviors of these scientifically intriguing and potentially very useful materials. Other materials of interest using the same experimental methods are perovskite superlattices and fullerene polymers. The latter system displays a pressure-induced insulator-metal transition similar to that seen in CMR systems, although the underlying physics is expected to be different. This research program is interdisciplinary in nature and involves several graduate students, who receive excellent training in preparation for careers in industry, government laboratories or academia. %%% This experimental basic research project focuses on the high sensitivity of the electrical resistance of a class of oxide materials to a magnetic field. This effect, which has become known as "colossal magnetoresistance" (CMR) is scientifically interesting and potentially of importance in improved technology. In this situation, the electrical resistance of the material is changed by an applied magnetic field, and such effects, which are usually very small, in these materials are usefully large. An attra ction of a magnetoresistive sensor is that it is more easlily minaturized, simpler, and cheaper to produce, than, say, the coil of wire in many traditional magnetic pickup devices. Magnetic sensors are well known in computer hard drives, magnetic tape recorders and other electronic applications, but are actually widespread in simpler applications like rotation speed sensors (tachometers) and many others. This experimental work focuses on CMR materials in the manganite perovskite class, and seeks to clarify the physical basis for the effect. The experiments concern the electronic, thermal and magnetic properties studied by means of transport and magnetic measurements. Much of the study will focus on the use of high pressures to which the CMR effect is particularly sensitive. Both teflon-seal and diamond anvil cells will be employed. Isotopic substitution will also be performed, independently and in conjunction with the pressure studies. Other materials of interest using the same experimental methods are perovskite superlattices and fullerene polymers. The latter system displays a pressure-induced insulator-metal transition similar to that seen in CMR systems, although the underlying physics is expected to be different. This research program is interdisciplinary in nature and involves several graduate students, who receive excellent training in preparation for careers in industry, government laboratories or academia. ***
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0.915 |
2002 — 2008 |
Zettl, Alex Frechet, Jean M. J. Crommie, Michael [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Nirt: Synthesis and Control of Molecular Machines @ University of California-Berkeley
CCR-0210176 Crommie, Michael
This proposal was received in response to the Nanoscale Science and Engineering initiative, NSF 01-157, category NIRT. The main objective of this project is to develop and characterize mechanical devices at the nanoscale. This will be performed through the creation of new, synthetic molecular machines purposefully designed in a molecule-by-molecule fashion. In order to achieve this goal an interdisciplinary team of researchers has been gathered that will engage in the following activities: 1) chemically synthesize new molecules having tailored properties to be used as nano-machine components, 2) adhere newly synthesized molecules to prepared surfaces and demonstrate mechanical functionality, 3) combine photolithographic MEMS technology with carbon growth techniques to create electro-mechanically actuated molecular motors from carbon nanotubes. Two new categories of functional molecular assemblies are expected to result from this research. The first involves chemically engineered molecules designed with specific mechanical functions in mind. This research thrust will be supported by a strong chemical synthesis effort aimed at the development of new classes of molecules able to undergo conformational changes when triggered by an outside stimulus. The second category involves the engineering of multi-wall carbon nanotubes to form the basis of a new mechano-molecular technology. This effort is expected to culminate in the demonstration of the first functional nanotube motor.
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0.915 |
2004 — 2012 |
Majumdar, Arunava (co-PI) [⬀] Zettl, Alex Howe, Roger (co-PI) [⬀] Howe, Roger (co-PI) [⬀] Maboudian, Roya (co-PI) [⬀] Yang, Peidong (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Nsec: Center of Integrated Nanomechanical Systems (Coins) @ University of California-Berkeley
The Nanoscale Science and Engineering Center entitled Center of Integrated Nanomechanical Systems (COINS) is a partnership between UC Berkeley, Caltech, Stanford and UC Merced. This team will interact closely with partners from national laboratories (Sandia and Lawrence Berkeley National Labs) and industry (HP, Nanosys, IBM, GE, Intel, Honeywell, and ChevronTexaco). The NSEC includes 27 investigators from 7 departments.
COINS has a focus on molecular and nanometer level mechanics at the interface of hard and soft matter, with five thrusts centering on an "element-to-device-to-system" research strategy: (I) Key Nanomechanical Building Blocks; (II) Theoretical Simulation of Nanomechanics; (III) Mechanical. Behavior of Nanostructure Elements; (IV) Instrumentations for Nanomechanical Measurements; and (V) Nanomechanical System Integration.
Chemical synthesis (Thrust I) plays a significant role in generating key nanomechanical building blocks including synthetic/biological molecules, nanotubes and nanowires. Computational schemes at the atomistic and continuum levels (Thrust II) will be developed to address the scaling effects observed in the experiments and offer theoretical insight and guidance for the experimental works in COINS. Research Thrust III probes the intrinsic mechanical behaviors of the key nanomechanical building blocks produced in Thrust I. Optical tweezers, AFM/STM and in-situ TEM are used to systematically study the quality factor, strength, friction, wear, and energy dissipation at nanometer scale. In addition, novel nanomechanical testing procedures and devices (Thrust IV) will be designed in order to assess the mechanical properties of the nanomechanical building blocks. These include AFM systems for RF resonator characterization, MEMS-based testing platforms for nanostructures, and non-contact nanomechanical instrumentation. Thrust V will tackle the system integration issues utilizing nanomechanical units developed and characterized in the other four thrusts. Here, the bottom-up synthetic techniques will substantially leverage the conventional top-down approaches for NEMS fabrication. Concepts of selforganization will be adapted from nature in intriguing biological mechanical systems. Thrust V will ultimately enable the integration of individual devices into fully functional nanomechanical systems capable of performing highly complex tasks. All five thrust areas will be represented at Berkeley; Stanford University will contribute to Thrusts II, III, and IV, and Cal Tech will contribute to Thrusts III, IV, and V.
The Center has broader impacts in addressing the real-time study of nanotechnology as a leading edge system of innovation; the influence of the intellectual property system; standard-setting; control on emerging nanotechnological industries; industrial location, both within the United States and around the world; and the management of risks-both real risks and the perception of risks created by potentially disruptive technologies.
Educational efforts within COINS will not only encompass the scientific themes proposed for the Center, but also address the broader need of workforce training in the emerging world of nanoscale science and technology. COINS includes an education program involving the general public, high school and college students to attract them to the diverse educational paths and career opportunities. A "Capital Science" workshop program will be designed to help state legislators and their staff make better policy decisions on issues with a significant scientific and technical dimensions. As a result of the NSF IGERT and the Designated Emphasis in Nanoscale Science and Engineering, Berkeley is in the process of developing a number of new graduate and undergraduate courses in nanoscience. In particular, an introductory course on nanoscience and a course on nanomechanics will be developed. In addition, COINS will support education and outreach activities at UC Merced, which will open in August 2005, and is likely to qualify as a Hispanic-Serving Institution. The Chancellor of UC Merced has set a goal to enroll half of the student body from the Central San Joaquin Valley, an economically and educationally underserved area. Fifty-three percent of the students demonstrating an interest in UC Merced were from households with incomes of $40,000 or less. We will focus on creating online modules that cover key concepts in nanoscience. Undergraduates from UC Merced and partner community colleges will construct the modules, under the supervision of graduate students and faculty. This experience will also include time in residence in the laboratories of faculty participants. This will enable their exposure to university research early on in their academic careers. The courseware developed in this effort will be used in K-12 outreach efforts that UC Merced faculty will undertake in the lower Central Valley. In addition, a nanoscale technology component will be incorporated into the Environmental Engineering program, one of the opening majors for UC Merced.
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0.915 |
2006 — 2007 |
Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
6th Nsf-Mext Joint Symposium On Nano-Systems @ University of California-Berkeley
CMMI - 0652129
ABSTRACT:
A focused, bi-lateral US-Japan Workshop is proposed for October 10, 11 and 12 of 2006 at the University of Tokyo, Japan, with leading researchers and engineers in the targeted area of building systems out of nanoscale elements. The workshop will explore the opportunities, barriers and challenges to these novel nanomaterials and systems. The possibilities for international collaboration between the two countries with major investment can be envisaged as a result of the Workshop. We will review the field by leading experts in both countries. This comes at an opportune time. Many exciting results on the structural, electronic, optical, and transport properties of nanoscale building blocks have already been achieved, and this symposium aims to provide a forum where experts in different aspects of nano systems get together, share information on the state-of-the-art of related research and discuss future prospects.
Intellectual Merits of the proposal activities. A nano system is a highly integrated system composed of many elements that have dimensions of nanometers. Unlike nano materials that are currently used in bulk or film form, the fabrication of the nano system requires nanometer accuracy in patterning, machining, positioning and interconnecting individual components. In order realize the nano system, it is necessary to combine different disciplines such as electronics, optics,mechanics(MEMS), material science, bio technology and chemistry in terms of fabrication and application. In other words, so-called bottom-up and top-down approaches are both required.
Broader Impact Resulting from the Proposed Activities. Observers from NSF and silicon valley companies will attend the Workshop. We will also advertise the workshop to selected academic and industrial labs to attract interested researchers to the audience to maximize the impact of the Workshop. The results of the Workshop will be presented in a report to NSF and made available for wide distribution, including presentation slides. The possibilities for international collaboration between the two countries with major investment can be envisaged as a result of the Workshop.
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0.915 |
2009 — 2012 |
Zettl, Alex Crommie, Michael [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Interactive Microscopy of Graphene Nanostructures @ University of California-Berkeley
******TECHNICAL ABSTRACT*******
Graphene is a remarkable newly isolated two-dimensional material that has novel physical properties and great potential for new nanotechnological advances. The central goals of this research project are to understand and control atomic-scale behavior in graphene nanostructures via newly developed techniques of "interactive microscopy". These methods allow graphene nanostructures to be not only probed at the atomic scale, but also to be manipulated. The strategy for this project revolves around the complementary use of scanning tunneling microscopy and transmission electron microscopy to characterize and manipulate graphene in a collaborative effort between the groups of M.F. Crommie and A. Zettl. Both microscopy techniques will be used in a coordinated, collaborative approach to explore the fundamental electronic and structural properties of graphene nanostructures such as edges, defects, nanoribbons, and nanoplatelets, and to correlate these properties with graphene nanodevice behavior. This project will provide scientific training to graduate students, undergraduates, and high school students in a strongly interdisciplinary area.
*******NON-TECHNICAL ABSTRACT********
Graphene is a remarkable new material that consists of a single sheet of carbon atoms chemically bonded in a periodic honeycomb pattern. This material has great promise for creating new electronic, magnetic, and mechanical devices that can be miniaturized beyond the level of current technology, with great potential advantages. To realize these advantages, however, the properties of graphene must be understood and controlled down to the atomic-scale (i.e., down to the size of single atoms). The central goal of this research project is to perform this task via newly developed interactive microscopy techniques. These techniques allow graphene to not only be imaged at atomic length scales, but also to be manipulated and changed at this same small length scale. Different state-of-the-art microscopy techniques with atomic-scale spatial resolution will be used in a coordinated, collaborative approach to explore the fundamental electrical and structural properties of graphene devices having different shapes and disorder properties at very small length scales. Critically important shapes include, for example, ribbons of graphene that have a width in the range of 10 nanometers. This project will provide interdisciplinary scientific training to graduate students, undergraduates, and high school students in the most powerful modern methods of microscopy and device characterization.
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0.915 |
2009 — 2014 |
Yang, Peidong (co-PI) [⬀] Zettl, Alex Maboudian, Roya (co-PI) [⬀] Liu, Tsu-Jae (co-PI) [⬀] Fearing, Ronald (co-PI) [⬀] Majumdar, Arunava (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
The Center of Integrated Nanomechanical Systems (Coins) Renewal Yrs 6-10 @ University of California-Berkeley
Center of Integrated Nanomechanical Systems (COINS)
Abstract
The goal of this program is to develop and integrate cutting-edge nanotechnologies into a versatile platform with various ultra-sensitive, ultra-selective, self-powering, mobile, wirelessly communicating detection applications. The success of this mission requires new advances in nano-electro-mechanical devices, from fundamental building blocks to enabling technologies to full device integration. The research approach combines five major thrusts that strive to push the limits of utilizing nanotechnology in Energy, Sensing, Mobility, Electronics, and Communication. Each of these areas encompasses research projects spanning the full spectrum of basic through applied levels. Deliverables include key advances in each research area as well as new approaches for integrating these advances together into a single, mobile sensing platform. An example includes the recent construction of a fully self-contained radio system with integral single-atom mass detection capability built out of a single carbon nanotube.
If successful, the program will lead to enhancements in environmental monitoring technologies that open new possibilities for detection via substantially better spatial and temporal resolution, for example the tracking of air- and water-borne pollutants and a better understanding of the impact of source emissions on ambient concentrations and human exposure. The mobile platform has the potential to fundamentally change the way one responds to proliferation events or serious natural catastrophic events by providing much more accurate information on conditions, allowing for improved countermeasures and security. The research components of this program are highly leveraged to prepare, recruit, and retain the nanoscale science and engineering workforce; to increase the participation of underrepresented minorities and women in nanoscale science and engineering in both industry and academia; and to increase the general public?s awareness and understanding of nanoscale science and engineering.
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0.915 |
2012 — 2018 |
Zettl, Alex Crommie, Michael [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Microscopy of Hierarchical 2-D Interface Structures @ University of California-Berkeley
****Technical Abstract**** The purpose of this project is to fabricate low-dimensional interface structures that enable the creation of new types of matter and the observation of new nanoscale phenomena. Such phenomena include interactions between atoms, molecules, and nanocrystals in low-dimensional environments defined by the interfaces between 2D layers of graphene and boron nitride (BN). This program will employ newly developed techniques for manipulating single layers of graphene and BN in order to fabricate low dimensional interface structures and to characterize them using scanning tunneling microscopy and transmission electron microscopy techniques. Interface structures will be decorated with a combination of atoms, molecules, and nanocrystal elements deposited via vacuum deposition and solvent-based spin-coating techniques. These structures will allow the exploration of completely new transmembrane chemical bonding and tunable electromagnetic behavior at the nanoscale. Graduate students, undergraduates, and postdoctoral researchers will be engaged at every level of this research, and will obtain training in state-of-the-art nanofabrication and microscopy techniques. High school students will be offered internships in this program to promote recruitment into the sciences.
****Non-Technical Abstract**** This project is aimed at characterizing new types of microscopic structures made by trapping atoms and nanometer-sized particles between two-dimensional layers of graphene and boron nitride (BN). Because the graphene and BN layers can be made only one-atom-thick, particles on either side of these membranes will interact strongly with one another, thus changing their overall properties in ways that have not been previously observed. Particles trapped at the interfaces between such membranes will be visible to different types of high-resolution electron microscopy, allowing their detailed behavior to be measured. This will allow the creation of new types of two-dimensional materials whose properties can be tuned into useful regimes that have never before been accessible (including, for example, their optical, electronic, and magnetic behavior). Such materials are expected to be useful in future electronic devices and also for creating new surface coatings with highly desirable properties. Graduate students, undergraduates, and postdoctoral researchers will be engaged at every level of this research, and will obtain training in state-of-the-art nanostructure fabrication and microscopy techniques. High school students will be offered internships in this program to promote recruitment into the sciences.
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0.915 |
2015 — 2019 |
Wang, Feng (co-PI) [⬀] Louie, Steven (co-PI) [⬀] Zettl, Alex Zhang, Xiang [⬀] Zhang, Xiang [⬀] Crommie, Michael (co-PI) [⬀] |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Efri 2-Dare: Valley Optoelectronics With Atomically Thin Transition Metal Dichalcogenides @ University of California-Berkeley
Nontechnical Description: This project is aimed at exploiting the novel electronic and optical properties of two-dimensional (2D) materials through the use of a unique set of devices built at the nanometer scale. The main strategy is to implement new techniques to control the quantum mechanical behavior of electrons in 2D materials by tuning how they interact with photons of light as well as with precise electrical signals. The optoelectronic devices explored in this project have the potential to improve high-speed data communications and low-power electronics in a transformative way. This project provides an ideal framework for multidisciplinary education, where physics and engineering students in different research areas can interact closely with each other. The project also partners with existing programs at Berkeley (such as the Berkeley Edge program) that are aimed at enhancing the recruitment and training of underrepresented and woman students engaged the frontier research in science and engineering.
Technical Description: This EFRI 2-DARE project aims to develop novel valleytronic and optoelectronic devices based on atomically thin transition metal dichalcogenide (MX2) crystals. Owing to their reduced dimensionality and high spin-orbital coupling, two-dimensional MX2 crystals (where M is a transition metal and X is a chalcogen) exhibit unusual quantum phenomena, including unique exciton physics and emergent valley degrees of freedom. An outstanding scientific question concerns the interplay between photons, excitons, and charge carriers with different valley and spin states in 2D MX2 crystals. This project aims at obtaining fundamental understanding of such interplay, and at developing novel valleytronic and optoelectronic devices based on these new insights. These goals will be achieved through an interdisciplinary and highly integrated approach that combines expertise in materials synthesis, spectroscopic characterization, device engineering, and theoretical modeling.
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0.915 |
2018 — 2021 |
Crommie, Michael [⬀] Zettl, Alex |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Interactive Microscopy of Hybrid Scattering Structures @ University of California-Berkeley
Non-technical Abstract The goal of this project is to understand how electrical current flows in small devices where it encounters obstacles whose size is on the order of the size of a single atom. This is important for miniaturizing electrical devices in order to make computers faster and more energy efficient, but it also creates new problems as the devices begin to reach sizes comparable to the distance between constituent atoms. In this size regime tiny defects such as a single misplaced atom - which might not have mattered in the past - suddenly can become very significant. The importance of this project is that it helps to clarify precisely how different atomic-scale objects affect electrical current in small devices, thus helping technology to be successfully miniaturized to the greatest extent possible. The difficulty here is the need to image atomic-scale structure inside actual operating devices to determine the cause-and-effect relationship between atomic-scale structure and device performance. This is accomplished using a scanning tunneling microscope that can see single atoms and also image electrons as they flow around the smallest possible obstacles, like water in a stream, according to the rules of quantum mechanics. Other types of microscopes are used that involve focused electron beams and helium ion beams to intentionally create atomic-scale structures that are not naturally occurring and thus intentionally manipulate the structure of electrical devices over the smallest distances possible. The broader impacts of this project lie in its strong education and outreach components and the fact that it provides high-level scientific training to graduate students, undergraduates, and high school students, preparing them for careers in STEM fields. Outreach efforts are performed at all levels by the investigators and team members and include creation of educational materials on nanoscience and technology for the Berkeley School/University Partnership Outreach Implementation Plan, as well as participation in the Bay Area Science in Schools program. Underrepresented minority students will be offered 5-week internships in the laboratories through the Summer Math and Science Honors Academy program at Berkeley, as well as mentoring opportunities through partnership with the UC Leadership Excellence through Advanced Degrees Program.
Technical Abstract The main goal of this project is to better understand how electrons in 2D materials interact with different structures at the atomic-scale under both equilibrium (i.e., zero transport current) and nonequilibrium (non-zero transport current) conditions. Conventional fabrication and imaging techniques are unable to access the atomic-scale for operational devices and so a gap has opened up in the understanding of how atomic-scale structures in 2D materials alter device functionality. This project will help to fill that gap by developing new techniques to synthesize atomically-precise structures in 2D devices and also to image them at the atomic-scale during device operation. A central question that is addressed is how the equilibrium electronic properties of microscopic scattering structures lead to their nonequilibrium response under high current density and differing device conditions. Specific objectives include the control and visualization of this behavior for point scatterers, quantum dots, and 1D superlattices at the surfaces of single-layer graphene field-effect transistor (FET) devices. Novel transmission electron microscopy (TEM), scanning tunneling microscopy (STM), and focused ion beam based synthesis techniques are used to modify boron nitride substrates with unprecedented spatial precision to engineer the electronic properties of graphene FET capping layers. This project combines the principal investigators' TEM, device fabrication, and scanned probe microscopy expertise to explore a unique set of nanoscale experimental systems. The intellectual merit of this project lies in the fact that it allows access to physical regimes that have never been explored, including the nonequilibrium properties of different atomic scale scatterers such as Coulomb impurities, resonant scatterers, and sp3 defects that break sublattice symmetry. The smallest possible atomically-precise quantum dots are explored in graphene, creating opportunity to visualize new types of edge-state behavior as well as electron lensing. Quantum dot wavefunctions are imaged with unprecedented resolution, enabling long-standing theoretical predictions to be tested. Defect behavior is studied in systems with engineered electrical anisotropy, a new frontier in 2D materials research.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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0.915 |