Millimeter-wave emission from current oscillations in semiconductor superlattices: present status and future prospects

Abstract

Recent results of millimeter wave generation with doped GaAs/AlAs superlattices are reviewed. The wide-miniband superlattices show negative differential conductance caused by Bloch oscillations of the miniband electrons. The millimeter wave emission is due to current oscillations driven by traveling dipole domains. The oscillation frequency is given by the ratio of the domain velocity and the superlattice length. The experimental results show that the oscillation frequency increases with increasing peak drift velocity, which strongly depends on the miniband width. Current oscillations in GaAs/AlAs superlattices up to a frequency of 103 GHz at a power level of about 0.5 mW are reported. The superlattice oscillator will be compared with resonant tunneling diode oscillators and Gunn diode oscillators. The possibility of using different material systems for the superlattices will be discussed.