Single-electron effects in slim semiconductor superlattices

Abstract

We fabricated laterally confined GaAs–AlGaAs superlattices with diameters between 500 nm and 2 μm. With decreasing device diameter, a gap evolves in the current–voltage curve around zero bias and steps show up at the onset of the current. This behavior is interpreted in terms of Coulomb blockade, a depletion of the center of the superlattice, and single-electron tunneling through donor levels.