In this paper we investigate the carrier cooling dynamics in graphene flakes exploiting ultrafast transient absorption imaging technique. This tool enables us to combine nanoscale spatial resolution and sub-picosecond (ps) time resolution. It provides many advantages over the standard transient absorption techniques because it directly investigates the excited state dynamics at a local scale that would be usually averaged out. The local dynamics show a photobleaching recovery in the first ps, assigned to cooling by electron–phonon scattering. We found that the photoexcited carrier dynamics is spatially uniform over the micrometer-sized exfoliated graphene layer. Ultrafast pump–probe technique is combined with an optical microscope to investigate the local excited state dynamics in graphene flakes.
|Titolo:||Ultrafast spectroscopic imaging of exfoliated graphene|
|Data di pubblicazione:||2012|
|Appare nelle tipologie:||01.1 Articolo in Rivista|
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|grancini_pssb_2012.pdf||Post-print||Accesso riservato||Accesso riservato|