Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 17: Poster I

HL 17.6: Poster

Monday, February 25, 2008, 16:30–19:00, Poster D

Morphology of graphene layers deposited on various substrates — •Ulrich Stöberl, Jonathan Eroms, Ursula Wurstbauer, Werner Wegscheider, and Dieter Weiss — Institut für Experimentelle und Angewandte Physik, Universität Regensburg

Following recent TEM studies on suspended graphene sheets, the ripple structure of graphene is believed to be an intrinsic property, influencing transport quantities, such as the minimum conductivity and the mobility of the carriers. Here, we investigate to what extent the roughness of the underlying substrate can modify the morphology of graphene layers. To this end, we have prepared single and few layer graphene samples using the mechanical exfoliation technique on standard, oxidized silicon wafers, and MBE grown GaAs and InGaAs wafers. The latter show a characteristic cross-hatched pattern with an rms roughness of about 5 nm, whereas the silicon wafers are smooth with a roughness below 1 nm. AFM investigations demonstrate that the surface of the graphene films is determined by the roughness of the underlying substrates. Furthermore this has important implications on the transport properties of the graphene film.