Engineering Physics Colloquium
Tuesday, November 12
4:00 PM to 5:00 PM
106 Engineering Research Building
Speaker: Professor Michael Arnold, University of Wisconsin - Madison
"Semiconducting Carbon Nanomaterials for Advanced Electronics and Light Harvesting"
Abstract: In this talk, I will detail two of our recent advances in (1) realizing carbon nanotube-based light harvesting materials and (2) graphene and graphene nanostructure engineering and CVD. (1) We have discovered how to efficiently harvest photons using semiconducting carbon nanotubes. Usually, when a film of nanotubes is illuminated, the photogenerated electron/hole pairs (excitons) are “stuck” to each other and rapidly lost to heat. We have overcome this problem and unlocked nanotubes’ potential as absorbers by (i) dramatically reducing their structural and electronic heterogeneity and (ii) discovering how to drive the dissociation of excitons in the materials using type-II donor/acceptor heterojunctions. (2) My group has pioneered a synthetic method for rationally growing graphene nanostructures by chemical vapor deposition (CVD) with tailored shape, size, and crystallographic orientation. Our approach called barrier-guided CVD (BG-CVD) confines the lateral crystal growth of monolayered graphene to nm-scale channels and features. This strategy for bottom-up growth coupled with the use of sub-10 nm lithographic templates formed using self-assembled block copolymers give us a powerful pathway for realizing wafer-scale arrays of high-quality nanostructured graphene materials with tailored and novel properties, with relevance for semiconductor electronics, infra-red optoelectronics, and spintronics.
Biography: Michael S. Arnold joined the faculty of the Department of Materials Science and Engineering at the University of Wisconsin-Madison as an assistant professor in August 2008. There, he has built a research program in the fundamental materials science of carbon nanomaterials (nanotubes, graphene, and related nanostructures). Prof. Arnold graduated summa cum laude from the University of Illinois at Urbana-Champaign with a Bachelor of Science degree in Electrical Engineering in 2001. He earned his Doctor of Philosophy degree in 2006 from Northwestern University in Materials Science and Engineering, pioneering carbon nanotube sorting with Prof. Samuel I. Stupp and Prof. Mark C. Hersam. Prof. Arnold also conducted post-doctoral research at the University of Michigan at Ann Arbor, with Prof. Stephen R. Forrest, where he studied organic materials for white lighting and photovoltaics. Arnold has been a recipient of the ACS Arthur K. Doolittle Award in Polymeric Materials Science and Engineering (2012); the Presidential Early Career Award for Scientists and Engineers (PECASE) – nominated by the U.S. Department of Defense, Army Research Office (2011); the U.S. Department of Energy (DOE) Early Career Research Award (2011); and a 3M Non-Tenured Faculty Award (2011, 2012, 2013).