Transition between static and dynamic electric-field domain formation in weakly coupled GaAs/AlAs superlattices

The transition between static and dynamic electric-field domain formation has been investigated in undoped, photoexcited GaAs/AlAs superlattices by varying the carrier density and temperature. The frequency spectra of the photocurrent oscillations exhibit as a function of bias voltage regions without any current oscillations. With decreasing carrier density or increasing temperature, these voltage regions become narrower. These observations indicate that with increasing carrier density the domain formation changes from dynamic to static. However, thermal activation appears to enhance the formation of dynamic domains. [S0163-1829(98)52036-X].