High Frequency DC Induced Oscillations in 2D

Abstract

In recent years DC induced current oscillations have been observed in many different types of 2d structures. In this paper we present results on GaAs/AlGaAs MQW structures that exhibit this behaviour at low temperatures (<260K) and low applied electric fields (<1KV/cm). The frequency of the oscillations depends to some extent on the applied electric field but was generally approximately 15MHz. The magnitude of the electric field at which the oscillations occur and the frequency of the oscillations mean that the well known mechanisms of DC induced current oscillations such as the Gunn Effect and the acousto-electric effect cannot be used in this instance. There are three current models^1,3,4 proposed to explain oscillations in 2d systems. Two of these models involve the interaction of carriers in the quantum well and the barrier. The third involves only carriers in the quantum well