Tunnel injection into a Wannier–Stark ladder

Abstract
We describe tunneling measurements of the electronic states of superlattices in which an electric field has destroyed the miniband structure. The tunneling characteristics reveal that the minibands collapse into localized Wannier–Stark states, which can be resolved in the first two quantum wells of the superlattice. The positions can be accounted for quantitatively by a combination of electrostatic and quantum mechanical effects.