Detailed electron microscopic investigations of the crystal structure defects exhibiting displacement fringe contrast in Te-doped GaAs (~-1 0 '~ 0 1 3 1~~) after thermal treatment at 800 to 900 "C are reported. These defects are demonstrated to be platelet-shaped precipitates resulting from decomposition of the supersaturated, solid solution of Te in GaAs. The displacement vector was found by a method based on the analysis of the intensities in the electron micrographs. The results are interpreted using the theoretical estimated distribution of Te impurity atoms caused by their interaction. npOBeAeHbI AeTanbHbIe 3JIeKTPOHHOMRKPOCKOnMgeCKMe HCCnenOBaHMH ne@eHTOB KpMCTaJIJlH~IeCHO% CTpYKTYpbl C KOHTpaCTOM nOJIOC CMeU(eHkifl B GaAs, JIerkipO-BaHHOM Te A 0 10" CM-3 Li IlOABeprHyTOM TepMOO6pa6OTKe npki 800 A 0 900 "c. nOKa3aH0, 9TO 3TM He@KTbI npeACTaBJIRI0T CO6Ofi IIJIaCTHB'iaTbIe BbIAeJleHAR M Ha OCHOBe aHaJIH3a PaCnpeneJIeHkiR MHTeHCABHOCTB Ha 3neKTpOHHOMMKpOCHOnki-nOJIy ¶eHHbIe pe3yJIbTaTbI PIHTepnpeTApyI0TCfi C I I O M O U b H ) TeOPeTH' ieCKHX OUeHOK PaCIIpeneJIeHMH IIpkiMeCHbIX aTOMOB Te, 06yCJIOBJIeHHOrO M X B3aklMOlle~CTBBeM. HBJIHIOTCH p e 3 y n b~a~o~ pacnana nepecmuemioro Tsepnoro pacmopa Te B GaAs. gecmx m06pame~wflx ne@eKToB onpeneneHa Bem'iwa HX semopa cMeqeaufi.

A calculation is made of the internal friction in GaP single crystals, produced by the reorientation of the divacancies of Ga atoms due to external stresses and the interaction between the vacancies. The ratio of the internal friction maxima in GaP, which correspond to the longitudinal oscillations in the [100] and [111] directions is found to be equal to 1.6, which is in good agreement with the results obtained experimentally for nondoped GaP single crystals with the help of the composite piezoelectrical oscillator method.

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