Graphene-based charge sensors

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.

7 pages, 7 figures

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Cited by in corpus (8)

• Robust and accurate electric field sensing with solid state spin ensembles
• High-sensitivity, spin-based electrometry with an ensemble of nitrogen-vacancy centers in diamond
• Fractional Coulomb blockade in a coupling controlled metallic quantum dot
• Single-electron Transport in Graphene-like Nanostructures
• Detection of the relaxation rates of an interacting quantum dot by a capacitively coupled sensor dot
• From diffusive to ballistic transport in etched graphene constrictions and nanoribbons
• Negative quantum capacitance in graphene nanoribbons with lateral gates
• Back action of graphene charge detectors on graphene and carbon nanotube quantum dots