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arXiv · 1304.0039

Graphene-based charge sensors

C. Neumann·C. Volk·S. Engels·C. Stampfer
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Abstract

We discuss graphene nanoribbon-based charge sensors and focus on their functionality in the presence of external magnetic fields and high frequency pulses applied to a nearby gate electrode. The charge detectors work well with in-plane magnetic fields of up to 7 T and pulse frequencies of up to 20 MHz. By analyzing the step height in the charge detector's current at individual charging events in a nearby quantum dot, we determine the ideal operation conditions with respect to the applied charge detector bias. Average charge sensitivities of 1.3*10^-3 e/sqrt{Hz} can be achieved. Additionally, we investigate the back action of the charge detector current on the quantum transport through a nearby quantum dot. By setting the charge detector bias from 0 to 4.5 mV, we can increase the Coulomb peak currents measured at the quantum dot by a factor of around 400. Furthermore, we can completely lift the Coulomb blockade in the quantum dot.

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C. Neumann, C. Volk, S. Engels, C. Stampfer. 2013-03-29. Graphene-based charge sensors. https://doi.org/10.1088/0957-4484/24/44/444001

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