Properties of a Monolithic Electroacoustic Device Geometry Using GaAs Resonant Tunnelling Structures

Abstract

We present experimental and theoretical work on a monolithic electroacoustic system which exploits the interaction between a 1 GHz surface acoustic wave and electrons in a GaAs-AlGaAs resonant tunnelling structure. Non-annealed Ohmic contacts using in situ grown Al are employed to obtain stable dc operation. The microwave response of the system is explained, with features attributed to charge accumulation in the spacer layer adjacent to the quantum well. The influence of screening of the surface acoustic wave potential by the highly-doped substrate is also investigated, showing the need for a wide depletion layer. Potential applications for this system in signal processing and power microwave devices are discussed, along with a suggested mechanism for a non-dispersive surface acoustic wave transducer which relies on the nonlinear properties of the system.