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Ballistic bipolar junctions in chemically gated graphene ribbons.

ABSTRACT: The realization of ballistic graphene pn-junctions is an essential task in order to study Klein tunneling phenomena. Here we show that intercalation of Ge under the buffer layer of pre-structured SiC-samples succeeds to make truly nano-scaled pn-junctions. By means of local tunneling spectroscopy the junction width is found to be as narrow as 5 nm which is a hundred times smaller compared to electrically gated structures. The ballistic transmission across the junction is directly proven by systematic transport measurements with a 4-tip STM. Various npn- and pnp-junctions are studied with respect to the barrier length. The pn-junctions are shown to act as polarizer and analyzer with the second junction becoming transparent in case of a fully ballistic barrier. This can be attributed to the almost full suppression of electron transmission through the junction away from normal incidence.

SUBMITTER: Baringhaus J

PROVIDER: S-EPMC4404713 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Ballistic bipolar junctions in chemically gated graphene ribbons.

Baringhaus Jens J Stöhr Alexander A Forti Stiven S Starke Ulrich U Tegenkamp Christoph C

Scientific reports 20150421

The realization of ballistic graphene pn-junctions is an essential task in order to study Klein tunneling phenomena. Here we show that intercalation of Ge under the buffer layer of pre-structured SiC-samples succeeds to make truly nano-scaled pn-junctions. By means of local tunneling spectroscopy the junction width is found to be as narrow as 5 nm which is a hundred times smaller compared to electrically gated structures. The ballistic transmission across the junction is directly proven by syste ...[more]

PMID: 25898259

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