Dresden 2017 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 30: Two-dimensional materials IV (jointly with HL/TT)
DS 30.2: Vortrag
Mittwoch, 22. März 2017, 09:45–10:00, POT 51
Ballistic transport in 2D periodically modulated graphene — •Andreas Sandner1, Martin Drienovsky1, Kenji Watanabe2, Takashi Taniguchi2, Dieter Weiss1, and Jonathan Eroms1 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Germany — 2NIMS, 1-1 Namiki, Tsukuba, Japan
Embedding graphene into a heterostructure with hexagonal boron nitride was shown to be an efficient way of achieving a high bulk mobility. The encapsulated graphene is protected in any further top-down fabrication procedure and pronounced commensurability features could be observed in 2D antidot lattices [1].
Here, we want to introduce a new method for periodical modulation of the carrier density, employing a few layer graphene patterned bottom gate. The bottom gate is defined by etching a 2D hole array into the few layer graphene and adapts perfectly to the commonly used stacking method for van der Waals heterostructures. By tuning the local bottom gate and the global back gate voltage, we can switch between the unipolar and bipolar transport regime.
We fabricated patterned bottom gates with lattice periods down to 150 nm and observe pronounced commensurability peaks that can be nicely compared to experiments with hard-wall graphene antidot lattices. We report on the difference between the unipolar and the bipolar regime, as well as the influence of the magnitude of the imposed superlattice potential.
[1] A. Sandner et al., Nano Lett. 15, 8402 (2015)