From One Electron to One Hole: Quasiparticle Counting in Graphene Quantum Dots Determined by Electrochemical and Plasma Etching

Quantum dots of around 20 nm in size are fabricated using local anodic oxidation. The behavior of the smallest dots in a magnetic field (see image) allows the identification of the charge-neutrality point and distinguishing of the states with one electron, no charge, and one hole left inside the quantum dot.