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Nano Lett. 2014 Sep 10;14(9):5371-5. doi: 10.1021/nl502114w. Epub 2014 Sep 2.

Experimental verification of carrier multiplication in graphene.

Author information

1
Institute of Semiconductor Electronics, RWTH Aachen University , Sommerfeldstrasse 24, 52074 Aachen, Germany.

Abstract

We report on the first direct experimental observation of carrier multiplication in graphene reaching a multiplication factor of up to 2 and persisting on a picoseconds time scale. Exploiting multicolor pump-probe measurement techniques, the excited nonequilibrium carrier distribution is retrieved on an ultrafast time scale. This provides access to the temporal evolution of the optically excited carrier density and thus allows quantitative conclusions on possible carrier multiplication. Microscopic time- and momentum-resolved calculations on the ultrafast relaxation dynamics of optically excited carriers confirm the observation of carrier multiplication under corresponding experimental conditions, suggesting graphene as a promising material for novel high-efficiency photodetection devices.

KEYWORDS:

Auger scattering; Graphene; carrier multiplication; relaxation dynamics

PMID:
25144320
DOI:
10.1021/nl502114w

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