A gate defined quantum dot on the two-dimensional transition metal dichalcogenide semiconductor WSe2

TL;DR

This paper demonstrates gate-defined quantum dots on WSe2, a 2D TMDC, using electric fields to achieve tunable quantum confinement without edge-induced defects, advancing quantum nano-device research.

Contribution

It introduces a fabrication method for gate-defined quantum dots on WSe2 that avoids edge states, with tunable size and consistent Coulomb blockade measurements.

Findings

Over 40 Coulomb diamonds observed

Quantum dot size tunable by a factor of 2

Charging energy approximately 2 meV

Abstract

Two-dimensional layered materials, such as transition metal dichalcogenides (TMDCs), are promising materials for future electronics owing to their unique electronic properties. With the presence of a band gap, atomically thin gate defined quantum dots (QDs) can be achieved on TMDCs. Here, standard semiconductor fabrication techniques are used to demonstrate quantum confined structures on WSe2 with tunnel barriers defined by electric fields, thereby eliminating the edge states induced by etching steps, which commonly appear in gapless graphene QDs. Over 40 consecutive Coulomb diamonds with a charging energy of approximately 2 meV were observed, showing the formation of a QD, which is consistent with the simulations. The size of the QD could be tuned over a factor of 2 by changing the voltages applied to the top gates. These results shed light on quantum nano-devices on TMDCs for further researches.