Mechanically tunable graphene Quantum Dot

Researchers create a mechanically tunable graphene quantum dot - Credit: TU Delft

Researchers at Delft University of Technology (TU Delft) have presented the first mechanically tunable monolayer graphene Quantum Dot (QD) whose electronic properties can be modified by in-plane nanometer displacements.

Precisely manipulating individual charge carriers is a cornerstone for single-electron transistors and for solid-state qubits. 

In order to access both the electrical and mechanical information from the sample, the researchers used a platform called the mechanically controlled break junction to measure the electromechanical properties of their device during three-point bending. The sample consists of a van der Waals heterostructure made by stacking several 2-D material flakes on top of a flexible substrate: a graphite back gate to electrostatically control the current through the device, a hexagonal boron nitride dielectric layer and a monolayer graphene conducting channel.

The results of the room-temperature measurements during bending demonstrate that the graphene, patterned into a nanobowtie shape with a constriction width of 160 nm, eventually breaks (zero current) but can also be remade (microampere currents) due to sliding and overlapping of the graphene edges. (

The paper has been published in Nano Letters.

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