High-frequency self-sustained current oscillation in an Esaki-Tsu superlattice monitored via microwave emission

Abstract We report the observation of a high-frequency self-sustained current oscillation in an n doped GaAs AlAs superlattice (at room temperature) that shows a negative differential conductance (Esaki-Tsu superlattice). The superlattice biased in the region of the negative differential conductance emitted microwave radiation at a fundamental frequency of about 6 GHz and at harmonics. We attribute the oscillation to space charge instabilities inside the superlattice caused by Bragg reflection of electrons in the lowest, wide miniband.