Eleventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. IV France 06 (1996) C8-871-C8-874
Internal Friction and Photoacoustic Effects in A2B6 and A2B7(HgI2) Single Crystals at Different Levels of Ultrasound Strain AmplitudeB.K. Kardashev
A.F. Ioffe Physico-Technical Institute of the Russian Academy of Sciences, St. Petersburg, 194021, Russia
A comparison of effects in damping and Young modulus under the influence of illumination for ZnSe and HgI2 demonstrates quite different mechanisms of photoacoustic interaction in the crystals : a drift of photocarriers in the electric field which arises due to piezoelectricity for the first case and a dislocation pinning mechanism for the second one. Spectral responses of the photoacoustic effect in both amplitude independent and dependent damping range are presented for mercury iodide crystals. The newly found acousto- and photo-optic effects in the luminescence spectrum of HgI2 allow one to specify the photosensitive dislocation pinning centre as an exciton state of carriers on a stoichiometric point defect of the lattice (iodine or mercury vacancy or interstitial).
© EDP Sciences 1996