Thz Band Gap In Encapsulated Graphene Quantum Dots

Graphene possesses many exceptional properties that are highly attractive for THz technology. However, opening a band gap in graphene is a crucial step toward practical THz applications. Here, we report high-quality encapsulated graphene quantum dots of 240 nm diameter that possess a gap frequency within the THz range. The encapsulation of the graphene with hexagonal Boron Nitride layers provides reduced disorder by preserving the graphene from chemical contamination during nanopatterning process and also by a weak perturbation of the substrate. Encapsulated graphene quantum dots open the way to achieve low doping regimes that is crucial for operation at THz frequency.