Transition between coherent to incoherent superlattices transport

Ballistic electron transport is used to study the transmittance of GaAs/GaAlAs superlattice. In a three terminal transistor type devices an energy tunable electron beam is injected via a tunneling barrier into an undoped superlattice. The transmitted current is measured as function of the injector energy. Resonance in the collector current are observed due to miniband conduction in the GaAs/AlGaAs superlattice. A significant decreased of the miniband transmission is observed with increasing electric field across the superlattice, which is attributed to the the quenching of coherent transport. For longer superlattices an asymmetry between positive and negative bias is found which is assigned to the transition between coherent and incoherent transport.