Energy spectrum of the quantum-dot in a Si single-electron-device

We have extracted the energy spectrum of the quantum dot in a Si single electron transistor from the gate voltage and drain voltage dependence of the drain current. The device used is a point contact MOSFET acting as a single quantum dot transistor fabricated on a SOI substrate using the anisotropic etching technique. The width of the most constricted part of the channel is less than 10 nm. Negative differential conductance is observed in the single electron transistor. The experimental results suggest that accurate understanding of the electronic states in the dot becomes much more important for the design of extremely small single electron devices for room temperature operation.