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

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Two-dimensional layered materials, like transition metal dichalcogenides (TMDCs), offer unique electronic properties for future electronics.
• Atomically thin quantum dots (QDs) can be formed on TMDCs due to their inherent band gap.

Purpose of the Study:

• To demonstrate the fabrication of quantum confined structures on WSe2 using electric-field-defined tunnel barriers.
• To eliminate edge states commonly found in gapless graphene QDs by avoiding etching steps.

Main Methods:

• Utilized standard semiconductor fabrication techniques.
• Employed electric fields to define tunnel barriers for quantum confinement.
• Investigated quantum dot formation and characteristics through electrical measurements.

Main Results:

• Successfully demonstrated quantum confined structures on WSe2.
• Observed over 40 consecutive Coulomb diamonds, indicating QD formation with a charging energy of ~2 meV.
• Tuned the QD size by a factor of 2 using applied gate voltages, consistent with simulations.

Conclusions:

• Established a method for creating smaller quantum dots on TMDCs compared to traditional GaAs/AlGaAs heterostructures.
• The electric-field-defined approach offers a pathway for advanced electronic devices utilizing TMDC-based QDs.