  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.
