Physics Colloquium: The Carbon Scaffold: Building Next-Generation Materials and Devices on Quasi-freestanding Epitaxial Graphene
Prof. Kevin Daniels, University of Maryland
Abstract: Two-dimensional materials possess unique mechanical, optical, and electronic properties that can exceed those of their bulk crystal counterparts. For example, graphene, a two-dimensional material composed of a single layer of carbon atoms, exhibits exceptionally high carrier mobilities (~100,000 cm2/Vs), high surface area (2630 m2/g), quasi-ballistic transport of carriers, ability to support surface plasmons and low noise making it an attractive material for various applications in electronics, optics, and sensing. In this talk, I will focus on the synthesis and applications of quasi-freestanding epitaxial graphene (QEG) on silicon carbide, grown from the sublimation of silicon from silicon carbide and the subsequent hydrogen passivation of silicon carbide substrate, for chemical and biological sensing, plasmonics, electron emission, and electrochemical material growth. I will discuss phenomena observed in QEG, from polarization-induced strain enabling the selective detection of very few copies of viruses like SARS-CoV-2, the virus responsible for COVID-19, to phonon-assisted electron emission, enabling emission of electrons at only 150°C, and the rapid electrodeposition of layered transition metal oxides for gas sensing. This work is enabled by and arises from the higher quality and single-crystal nature of epitaxial graphene compared to other growth graphene growth methods and the reduction in carrier scattering and electron-phonon coupling due to the quasi-freestanding nature of the QEG.
Biography: Dr. Kevin Daniels is an Assistant Professor of Electrical and Computer Engineering and the Institute for Electronics and Applied Physics at the University of Maryland, College Park, and director of the Dimensional Materials Laboratory (DML), which focuses on exploiting the electrical, optical, and mechanical properties of 2D and low-dimensional materials synthesized in the lab for chemical and biological sensing, quantum science and plasmonics. He received his B.S., M.E., and Ph.D. from the University of South Carolina in 2009, 2012, and 2014 respectively. Before joining the University of Maryland faculty in 2017, he was a National Research Council Postdoctoral Fellow residing at the U.S. Naval Research Laboratory from 2014-2017, receiving postdoctoral training from Rachael Myers-Ward and Kurt Gaskill. He is a National Science Foundation CAREER award (2022) recipient, and his scientific contributions have led to 40 publications in 2D and wide bandgap semiconductor material synthesis, characterization, and applications.