Surface-acoustic-wave study of defects in GaAs grown by molecular-beam epitaxy at 220 °C

Phys. Rev. B 45, 4258 – Published 15 February 1992
Ken Khachaturyan, Eicke R. Weber, and Richard M. White


Surface acoustic waves (SAW’s) were used to study the influence of defects on the elastic properties of epitaxial films of semiconductors. The object of this study was As-rich GaAs grown by molecular-beam-epitaxy at 220 °C. The SAW velocity on 0.3-wavelength-thick epilayers was 1.2% smaller than on the substrate alone. That velocity difference decreased after loss of some excess As as a result of 350 °C–435 °C anneals. A persistent increase as much as 0.4% of the SAW velocity at low temperatures was observed after illumination; this increase could be quenched by annealing at 120–130 K. This behavior is caused by the metastable transition of EL2-like AsGa defects and constitutes the direct experimental proof of the illumination-induced large lattice relaxation of this defect. The SAW velocity increase was correlated with the persistent bleaching of EL2-related optical absorption. The spectral dependence of rate of illumination-induced SAW velocity increase was measured.


  • Received 6 September 1991
  • Published in the issue dated 15 February 1992

© 1992 The American Physical Society

Authors & Affiliations

Ken Khachaturyan and Eicke R. Weber

  • Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94120
  • Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720

Richard M. White

  • Berkeley Sensor & Actuator Center, Electronics Research Laboratory, Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720

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