Effects of level broadening and electron overheating in tunneling structures based on metal clusters

The effect of level broadening and electronic subsystem overheating of disk-shaped and spherical gold clusters/islands on the current-voltage characteristic of the three-electrode structure has been studied. A scheme for calculating the electronic level broadening in the one-dimensional case of rectangular barriers has been proposed. In the two-temperature electron-ion model of a metal cluster, taking into account the size dependence of the Debye frequency, the kinetic electron temperature has been estimated as a function of the bias voltage. At low ion temperatures, the broadening and electron overheating effects result in disappearance of steps of quantum and Coulomb staircases, i.e., a strong smoothness of the current-voltage characteristic even in structures on clusters consisting of a denumerable number of atoms, which is actually observed experimentally.