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Heat Transport across Graphene Interfaces – How Heat Can Be Efficiently Dissipated From Graphene Devices?

Dr. KOH Yee Kan
Thu, 08/11/2012 - 12:00pm to 1:00pm
Physics Conference Room 13-M01-11
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Many emerging devices including graphene devices contain a high density of interfaces, which are usually located in close vicinity of active functioning areas of the devices. Thus, knowledge on how heat is transported across the interfaces is crucial for the design and performance of these novel devices. Unfortunately, understanding of heat transfer at nanometer length scales is still incomplete, partly due to the challenges in measuring heat transport at such a small length scale. As a result, thermal management of the emerging devices is often designed in an ad hoc manner.

In this talk, I will present a state-of-the-art characterization technique, called time-domain thermoreflectance (TDTR), to measure the heat transport across interfaces. Using the novel technique, we studied the physics of heat transport across different interfaces. I will first discuss heat transport across atomically discrete semiconductor/semiconductor interfaces and how phonons are scattered by these interfaces. Then, I will present our TDTR measurements on metal/graphene interfaces, which advance our understanding on heat dissipation through graphene interfaces. Finally, I will present some preliminary measurements on heat transport across different metal contacts for graphene devices. Our results facilitate choices of metal contacts for better thermal management of future graphene devices.


KOH Yee Kan received a B.S. and a M.Eng. in Mechanical Engineering from the University of Technology Malaysia. In 2004, he enrolled in the University of Illinois at Urbana-Champaign, and obtained a M.S. in Physics in 2007 and a Ph.D. in Materials Science and Engineering in 2010 from the university. After his graduation in 2010, Koh joined the Department of Mechanical Engineering in National University of Singapore (NUS) as an assistant professor. Koh’s expertise is in heat transport in nanostructures and across interfaces, with emphasis on applications in thermoelectric energy conversion and thermal management of emerging electronic devices (e.g., graphene devices). Koh is an expert in time-domain thermoreflectance (TDTR), a modulated pump-probe technique to measure heat conduction on nanometer length scales. He has published 13 papers on nanoscale heat transport and has received numerous awards, including the Ross J. Martin award (2010), SMF-NUS Research Horizons Award (2010), NUS Young Investigator Award (2011), and the prestigious Fulbright fellowship (2004).

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