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Zachary C. M. Winter: Point contacts in dry transferred ultrahigh-mobility CVD graphene

posted 18 Jul 2016, 04:48 by info admin
Z.C.M. Winter, L. Banszerus, M. Schmitz, A. Epping, T. Khodkov, T. Taniguchi, K.  Watanabe, B. Beschoten, and C. Stampfer
JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany

A novel dry transfer process is shown for graphene grown by chemical vapor deposition (CVD) utilizing van der Waals forces to lift it directly off the Cu substrate without using wet chemicals or any intermediary contact with epoxy, polymers, or other chemical agents. Carrier mobilities have been reported as high as 350,000 cm2/Vs at around 2K [1] as well as ballistic transport exceeding 28µm [2] using this technique. We use such ultrahigh-quality graphene samples and demonstrate the fabrication of sub-micrometer internal point-like contacts – expected less invasive than side contacts and useful for the fabrication of electron-optical devices. This is important for experiments where the graphene edge poses a potential problem to measuring transport and has to be avoided. In summary, we present details on the complete fabrication process of making CVD graphene hBN heterostructures with non-invasive electrical contacts. 

[1] L. Banszerus, M. Schmitz, S. Engels, J. Dauber, M. Oellers, F. Haupt, K. Watanabe, T. Taniguchi, B. Beschoten, and C. Stampfer, Science Advances 1, e1500222 (2015)
[2] L. Banszerus, M. Schmitz, S. Engels, M. Goldsche, K. Watanabe, T. Taniguchi, B. Beschoten, and C. Stampfer, Nano Lett. 16, 1387 (2016)

Zachary Winter is currently a master’s student studying physics at the RWTH Aachen University. He’s currently working in the group of Prof. C. Stampfer and is interested in the CVD synthesis of graphene and the fabrication of electron-optical devices therewith as well as materials science. He received his B. S. in Physics from Montana State University, Bozeman (2014) where he conducted magnetic transport measurements in superconducting polycrystalline YBCO as well as phase transitions in single crystalline CuO.