Physics Seminar
Wednesday, October 15, 4:10 - 5:30 PM
Biology 19
This event is open to the public.
Matthew Graham, Oregon State University, on "Micro-Femto Energetics: Nano-Physics in the Twinkling of an Eye."
When light and matter interact, electron micro-femto energetics begin. Our just-constructed lab is able to ‘film’ the excited electron’s energetic journey from light absorption to photocurrent generation with sub-micron (<10-6 m) spatial resolution and femtosecond (~10-15 s) time-resolution. By 'filming' how electrons move and relax at nanoscale interfaces, we identify the bottlenecks that inherently limit the efficiency of solar voltaics and photosensors. We will show how our ultrafast ‘moives’ give a time-space resolved microscopy map of the electronic population in materials such as graphene and single atomic layer dichalcogenides devices. For graphene, our measurements reveal how electrons relax near the Fermi energy through a radically accelerated supercollision mechanism. The discovery of this novel electronic mechanism provides the missing link required to predict current generation from electronic population in graphene.
For more information, contact Mary Sullivan.
Posted on Oct 9, 2014
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