2.1 Characteristic Energies

   Charging an island with a small number of electrons is associated with two kinds of energies. One kind arises from electron-electron interaction and the other is linked to the spatial confinement of electrons. These energies are only significant for very small structures in the nanometer regime. Otherwise they are masked by thermal fluctuations.

We discuss two other important characteristic energies, the work done by the voltage sources and Helmholtz's free energy, and the role they play in single-electron device behavior.