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O: Fachverband Oberflächenphysik
O 77: Poster Session - 2D Materials: Stacking and Heterostructures
O 77.1: Poster
Mittwoch, 18. März 2020, 18:15–20:00, P2/EG
Electronic transport in graphene on monolayer hexagonal boron nitride on the local scale — •Benno Harling, Anna Sinterhauf, and Martin Wenderoth — IV. Physikalisches Institut, Universität Göttingen, Germany
The promising electronic transport properties of the first true two-dimensional material graphene are known to be strongly affected by interactions with the substrate below the graphene sheet. One method currently being considered to reduce this influence is the use of suitable dielectric substrates such as boron nitride.
Here, we use the AFM-based method of Kelvin probe force microscopy with additionally applied in-plane bias voltage [1] to investigate the local electronic transport properties of the commercially available van-der-Waals-system monolayer graphene on monolayer hexagonal boron nitride on SiO2 under ambient conditions. Our measurements reveal a highly inhomogeneous transport behavior. We find a strongly locally varying potential gradient as well as local voltage drops. These local voltage drops depend on the direction of the current flow through the sample and on the current density. The asymmetric behavior of the device under current flow reversal is additionally observed in macroscopic measurements. Furthermore, we find a dependence of the sheet resistance on temperature and propose a model based on a resistor network consisting of ohmic resistors and diodes, with which it is possible to describe large parts of the experimental findings. Financial support by the DFG through project We 1889/13-1 is gratefully acknowledged.
[1] Willke et al., Carbon 102, 470-476 (2016)