Gate-Tunable Quantum Dot in a High Quality Single Layer MoS$_{\mathrm{2}}$ Van der Waals Heterostructure

TL;DR

This paper demonstrates the creation of a gate-tunable quantum dot in a high-quality monolayer MoS2 heterostructure, showing Coulomb blockade and double dot behavior, advancing quantum device applications in 2D materials.

Contribution

It introduces a novel fabrication method for quantum dots in monolayer MoS2 with tunable properties and observes Coulomb blockade and double dot phenomena.

Findings

High electron mobility of 3000 cm²/Vs at low temperature

Observation of Coulomb blockade in MoS2 quantum dot

Realization of double quantum dot regime with honeycomb charge stability pattern

Abstract

We have fabricated an encapsulated monolayer MoS$_{\mathrm{2}}$ device with metallic ohmic contacts through a pre-patterned hBN layer. In the bulk, we observe an electron mobility as high as 3000 cm$^{\mathrm{2}}$/Vs at a density of 7 $\times$ 10$^{\mathrm{12}}$ cm$^{\mathrm{-2}}$ at a temperature of 1.7 K. Shubnikov-de Haas oscillations start at magnetic fields as low as 3.3 T. By realizing a single quantum dot gate structure on top of the hBN we are able to confine electrons in MoS$_{\mathrm{2}}$ and observe the Coulomb blockade effect. By tuning the middle gate voltage we reach a double dot regime where we observe the standard honeycomb pattern in the charge stability diagram.