Markus Rotter, Werner Ruile, Achim Wixforth, and Jörg P. Kotthaus
ABSTRACT The combination of the electronic properties of semiconductor heterojunctions and the acoustic properties of piezoelectric materials yields very promising surface acoustic wave (SAW) hybrid systems. Quasi-monolithical integration of thin GaAs/InGaAs/AlGaAs-quantum well structures on LiNbO3 SAW devices is achieved using the epitaxial lift-off (ELO) technique. The conductivity of the two-dimensional electron system in the quantum well, which can be controlled via field effect, modifies the velocity of the SAW. Due to the high electromechanical coupling coefficient of LiNbO3 a large phase shift can be obtained. As an example for this new class of voltage-tunable single chip SAW devices, a voltage-controlled oscillator (VCO) is presented in which the output frequency can be tuned by an applied gate voltage.
1999 IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control Vol. 46, pp. 120-125, 1999
© 1999, by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.