Part II, Measurement*

To confine charge carriers and define quantum dot in WS, a monolayer and a bilayer of WS have been encapsulated with hexagonal Boron Nitride (hBN) layers and transferred to the local accumulating and confining gates. We have observed the Coulomb blockade effects at temperatures as low as 30 mK in our p-type quantum dots where we were able to estimate the gate-tunable size of the quantum dot. For the first time, single quantum excited states in WS quantum dot are realized and confirmed through temperature dependency of resistance peaks. We will also report observation of an unprecedented ambipolar behavior in WS quantum dot.