Miniband Transport and Resonant Tunneling in Superlattices

Recent experimental results of miniband transport in superlattices are reviewed. The Bloch type of conduction is observed either for electron or for hole minibands. The nonlinear conduction in the superlattice direction is obtained by means of either pure electrical methods or by time resolved and spectral photoconduction data. In short period superlattices, the negative differential conductivity is different from that of a resonant tunneling between different subbands. The microscopic origin of the observed phenomena can be interpreted either in terms of Esaki-Tsu non-linear effective mass or in terms of resonant tunneling in WannierStark “localized” states.