Microscopic view on the ultrafast photoluminescence from photoexcited graphene.

Winzer, Torben; Ciesielski, Richard; Handloser, Matthias; Comin, Alberto; Hartschuh, Achim; Malic, Ermin · Nano Lett · 2015

basic_science · Level V

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Abstract

We present a joint theory-experiment study on ultrafast photoluminescence from photoexcited graphene. On the basis of a microscopic theory, we reveal two distinct mechanisms behind the occurring photoluminescence: besides the well-known incoherent contribution driven by nonequilibrium carrier occupations, we found a coherent part that spectrally shifts with the excitation energy. In our experiments, we demonstrate for the first time the predicted appearance and spectral shift of the coherent photoluminescence.