Temperature dependence of Coulomb oscillations in a few-layer two-dimensional WS2 quantum dot

TL;DR

This study investigates how temperature affects Coulomb oscillations in a WS2 quantum dot, revealing linear broadening of peaks with temperature and suggesting a more uniform confining potential compared to graphene QDs.

Contribution

It provides the first detailed analysis of temperature dependence of Coulomb oscillations in WS2 quantum dots, highlighting differences from graphene QDs and implications for potential uniformity.

Findings

Coulomb peak width increases linearly with temperature

Peak height remains nearly constant across temperatures

WS2 QDs exhibit uniform potential unlike graphene QDs

Abstract

Standard semiconductor fabrication techniques are used to fabricate a quantum dot (QD) made of WS2, where Coulomb oscillations were found. The full-width-at-half-maximum of the Coulomb peaks increases linearly with temperature while the height of the peaks remains almost independent of temperature, which is consistent with standard semiconductor QD theory. Unlike graphene etched QDs, where Coulomb peaks belonging to the same QD can have different temperature dependences, these results indicate the absence of the disordered confining potential. This difference in the potential-forming mechanism between graphene etched QDs and WS2 QDs may be the reason for the larger potential fluctuation found in graphene QDs.