Title: Nano-infrared imaging and spectroscopy of epitaxial graphene on SiC
Abstract: Epitaxial graphene on silicon carbide (SiC) is one of the most important types of graphene for technological applications due to its scalability, high quality, a
nd potential for generating new electronic properties. In this work, we demonstrate that scattering-type scanning near-field optical microscopy (s-SNOM) is a powerful and efficient technique for characterizing epitaxial graphene due to its capability of high-resolution infrared (IR) imaging and spectroscopy. With nano-IR imaging, we were able to map microscopic graphene domains with various thicknesses and doping. With nano-IR spectroscopy, we found the mapped graphene domains have distinct IR contrasts at different spectral regions due to their interactions with the optical phonon resonance of SiC. Furthermore, we performed quantitative modeling of the nano-IR spectra, based on which we were able to estimate the Fermi energy of the different graphene domains. Our work uncovered new IR responses and surface properties of epitaxial graphene on SiC and paved the way for future large-scale applications of epitaxial graphene in wafer-scale electronics and optoelectronics.
Bio: Michael Orcino Fralaide is a Ph.D. candidate in the Electrical Engineering department at Iowa State University working with co-major professors Dr. Zhe Fei and Dr. Rana Biswas. His current projects utilize scattering-type scanning near-field optical microscopy (s-SNOM) to study various 2D materials, such as pristine epitaxial graphene, graphene with metal intercalation, and graphene magnetoplasmons. His previous projects at Iowa State include using corrugated patterned plastic substrates to improve OLED light outcoupling and tunable perovskite-based optical sensing, under the direction of professors Dr. Joesph Shinar and Dr. Ruth Shinar.
Michael received his Master of Science in Applied Physics under Dr. Saikat Talapatra at Southern Illinois University Carbondale in 2015 with his thesis, “Electrical Transport and Photoconduction of Ambipolar Tungsten Diselenide and n-type Indium Selenide.” He graduated from Benedictine University in Lisle, IL in 2011 with his Bachelor of Science in Physics under Dr. Andrew Wig, where he studied the motility strength of E. coli bacteria using optical tweezers.
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