Multi-peak negative differential resistance arising from tunneling current through few germanium quantum dots

Metal-oxide-silicon(MOS) capacitors incorporating 2 ~ 3 germanium (Ge) quantum dots (QDs) in the gate oxide were fabricated to exhibit multi-peak negative differential resistance (NDR) for multiple-value memories and logics. The tunneling current through the Ge-QD MOS capacitors is theoretically and experimentally studied. We found that negative differential resistance (NDR) arises from the interdot Coulomb interactions and the QDs with shell-filling conditions. The experimental results qualitatively match with theoretical prediction.