Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 62: Graphene: Applications, Luminescence and Spin Relaxation (HL with O/TT)

O 62.5: Vortrag

Mittwoch, 18. März 2015, 17:45–18:00, ER 270

Ultrafast photocurrents in back-gated graphene — •Felix Schade, Andreas Brenneis, Jose A. Garrido, Simon Drieschner, and Alexander W. Holleitner — Walter Schottky Institut and Physik-Department, Technische Universität München, Am Coulombwall 4a, Garching, Germany

We present picosecond time-resolved photocurrent measurements of back-gated CVD grown graphene on sapphire substrates. We examine the optoelectronic dynamics with respect to (i) the thermal coupling of graphene to its environment [1], (ii) different doping levels by tuning the back-gate voltage with respect to the Dirac point, and (iii) thermoelectric, photovoltaic as well as bolometric contributions. To this end, the graphene sheets are contacted by a THz-stripline circuit, and the ultrafast response is read-out by an Auston-switch [2]. The back-gate is separated from the graphene by the help of ALD-grown sapphire.

The ERC grant NanoREAL is acknowledged.

[1] A. Brenneis, et al., Nature Nanotechnology, DOI: 10.1038/NNANO.2014.276 (2015). [2] L. Prechtel, et al. Nature Comm. 3, 646 (2012).