Spikes in the current self-oscillations of doped GaAs/AlAs superlattices

Abstract

In doped, weakly coupled superlattices, current self-oscillations occur due to a recycling motion of a charge monopole, which forms the boundary between two electric field domains. In addition to these fundamental oscillations, the current also contains a high-frequency modulation in form of spikes, which are caused by the tunneling process of the charge monopole over a single superlattice period. The number of spikes within one fundamental oscillation can therefore serve as a measure for the number of superlattice periods, which are involved in the recycling motion. Spiking may reflect non-stationary tunneling effects for sufficiently large applied electric fields.