TUNNELING THROUGH ROUGH BARRIERS

The mean current density through tunnelling barriers with rough surfaces is considered. Special attention is paid to the current-bias characteristic. The roughness is modelled by uniformly distributed short-ranged bumps. It is found that roughness causes a change of the effective barrier thickness according to the mean height deviation from the ideal surface and gives rise to a diffuse current contribution that enhances the current through the barrier. A generalization of the results using the local density of states is given.