Abstract
“Walking the Feynman’s Talk” with Focused Electron and Molecular Beams for Writing 3D Nanostructures and 2D Electronic and Quantum Materials
Focused Electron Beam Induced Processing (FEBIP) is a powerful method for atom-by-atom fabrication of topologically complex nanostructures from a variety of materials. Compared to a similar technique based on an ion beam, FEBIP can achieve higher resolution, inflicts minimal surface damage, and uses more accessible tools. It has unique potential to provide a comprehensive processing environment for emerging (bio)electronic and quantum devices based on 2D materials. We pioneered a family of multi-mode energized micro/nano-jet techniques for local precursor delivery to resolve the FEBID challenges and to expand the range of useful precursors from gas to liquid phase for broader FEBIP applications. Energized micro/nano-jets of thermally or electro-kinetically energized precursors in both gas and liquid phase provide unique capabilities for localized delivery of precursor molecules to the substrate, thus establishing locally controlled deposition/etching/doping site for FEBIP. This enhances the growth rate and purity by selectively tuning precursor sticking, diffusion, and adsorption/desorption activation energies. We demonstrated a new approach to FEBIP using liquid phase precursors delivered via a nanoelectrospray jetting process into a vacuum environment. This new technique, NESA-FEBIP, brings an important new dimension to direct-write nanofabrication by (1) extending the available precursor state from gas to liquid phase and (2) using the focused electric field rather than heating to activate new energy modes of the precursor molecules. Both purely aqueous and organic solvents have been successfully delivered by nanoelectrospray jets, enabling new FEBIP capabilities of (1) dramatically increasing the growth rate of deposition/etching, (2) enabling deposition of composite materials and alloys with tailored electromechanical properties, and (3) fabrication of new, truly 3D topologies of nanostructures that are fundamentally out of reach of current gas-phase FEBID techniques. These unique new capabilities of NESA-FEBIP are matched by the complexity of the underlying physics and chemistry of ion transport and electrochemical reaction interactions, which need to be understood on the most fundamental level to take full advantage of and further develop new FEBIP modes and applications to emerging electronic and quantum devices based on 2D materials. [1] I will discuss development and demonstration of a complete set of processing capabilities using FEBIP to fabricate devices from monolayer graphene, including high-resolution, high-speed etching, dynamic dopant patterning and n-p-n junction formation, low resistance, Ohmic contact at the metal-graphene junctions, and “direct-write” reduction of graphene oxide, forming high electronic mobility conductive line patterns for biosensing and bioelectronics. [2]
[1] Kim, S. and Fedorov, A.G., FEBIP for functional nanolithography of 2D nanomaterials, Nanofabrication: Nanolithography Techniques & Their Applications, J. M. De Teresa (Editor), Institute of Physics, UK, 2020.
[2] Wall Street Journal, The Nanotechnology Revolution Is Here—We Just Haven’t Noticed Yet, https://www.wsj.com/articles/the-nanotechnology-revolution-is-herewe-just-havent-noticed-yet11642827640?redirect=amp January 2022.
Biography
Andrei G. Fedorov is the Rae S. & Frank H. Neely Chair Professor in the Woodruff School of Mechanical Engineering at Georgia Tech. His current research focuses on electron-beam-mediated direct-write nanomanufacturing, MEMS-enabled bioanalytical instrumentation, understanding and prediction of brain temperature, and thermal management of high-power generation devices. Dr. Fedorov’s accomplishments have been recognized by peers, including the 2006 von Turkovich Outstanding Young Manufacturing Engineer Award from the Society of Manufacturing Engineers (SME) “for contributions and accomplishments in the manufacturing industry” and the 2007 Bergles-Rohsenow Award in Heat Transfer from the American Society of Mechanical Engineers (ASME) for “sustained contribution to heat, mass, and radiation transfer.” Most recently, Dr. Fedorov has been selected to become a recipient of the 2010 Gustus L. Larson Memorial Award, given jointly by Pi Tau Sigma (International Mechanical Engineering Honor Society) and the ASME, in recognition of outstanding achievements in mechanical engineering within ten to twenty years following graduation. In 2024, Georgia Clinical & Translational Science Alliance recognized Fedorov with the Presidents’ Award of Distinction for Team Science (jointly with Prof. Candace Fleischer, Emory University Medical School) for achievements in “Brain Thermometry Advances for Better Health."
Dr. Fedorov authored/co-authored over 200 archival articles published in premier technical journals and refereed conference/symposia proceedings, along with numerous plenary and keynote presentations at the major national and international conferences. He is a member of International Advisory Board of the Tokyo Tech’s Global Center of Excellence for Energy Science; serves on Editorial Advisory Boards of the Nanoscale & Microscale Thermophysical Engineering, the International Journal of Multiscale Computational Engineering, International Journal of Interfacial Phenomena and Heat Transfer, Journal of Nanoelectronics and Optoelectronics, and Transactions of the Japanese Society of Mechanical Engineers (JSME); and consults a number of government agencies and major corporations worldwide. Dr. Fedorov's research has led to development of new technologies for various applications, resulting in over 60 patented inventions. For his inventions of biomedical devices, the World Technology Network (WTN), in cooperation with AAAS Science Magazine, CNN and leading technology companies, selected Dr. Fedorov as a WTN Associate and one of twenty-five “most innovative people and organizations in the science and technology world” nominated for the 2005 World Technology Award in Health and Medicine. With his students and collaborators, he has started several technology companies to commercialize his inventions and was recognized with the inaugural Regents’ Entrepreneur title by the University System of Georgia (2022). Fedorov’s personal inspiration and angle to innovation come from his deep involvement with art and theatre, and he is a strong believer in creative power of “artist-scholar”.