Quantum Capacitance in Graphene - What is it Really Good For?

April 19, 2013
Location: Interschool Lab (750 CEPSR)
Hosted by: EFRC Special Seminar
Speaker: Prof. Steve Koester (University of Minnesota)


Graphene is a recently isolated two-dimensional material that has many unique and remarkable properties, including high mobility, broadband optical absorption and high mechanical strength that make it interesting for use in a wide variety of electronic and photonic device applications. Single-layer graphene also has very low density of states, which leads to strong quantum capacitance, an effect whereby the electrostatic potential changes as electrons are added or removed from the graphene. Though this property of graphene is well known, it remains a subject of some debate as to whether or not this property is really useful for device applications. In this talk, I will describe two novel graphene quantum capacitance device concepts: passive wireless sensors for biological and environmental sensing applications and optical modulators for high-speed, very lowpower, broadband optical communications. I will report on recent simulation and experimental results and will highlight the primary design and fabrication challenges involved with realizing these device concepts, as well as discuss their fundamental performance limitations.

Speaker Biography

Dr. Koester received his Ph.D. in 1995 from the University of California, Santa Barbara. From 1997 to 2010 he was a research staff member at the IBM T. J. Watson Research Center and performed research on a wide variety of electronic and optoelectronic devices, with an emphasis on those utilizing the Si/SiGe material system. From 2006-2010 he served as manager of Exploratory Technology at IBM Research where his team investigated advanced devices for use in advanced microprocessor technology. Since 2010, he has been a Professor of Electrical & Computer Engineering at the University of Minnesota where his research focuses in part on novel electronic and photonic device concepts. Dr. Koester has authored or co-authored over 160 technical publications and conference presentations, 7 volumes, 4 book chapters, and holds 41 United States patents. He is a senior member of IEEE and is an associate editor for IEEE Electron Device Letters.

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