Особливостi дислокацiйного поглинання ультразвуку в безсубблочних кристалах Cd0,2Hg0,8Te

• Main Authors: Lysyuk, I. O., Olikh, Ya. M., Olikh, O. Ya., Beketov, G V.
• Format: Article
• Language: English; Ukrainian
• Published: Publishing house "Academperiodika" 2018
• Subjects: ultrasound; dislocations; CdxHg1−xTe; ультразвук; дислокацiї
• Online Access: https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2018412

The temperature dependence of the ultrasound wave absorption in bulk p-Cd0.2Hg0.8Te crystals free from low-angle grain boundaries has been studied experimentally for the first time in the frequency range 10–55 MHz and the temperature interval 150–300 K, and the corresponding results of measurements are presented. The maximum value of absorption coefficient is found to increase and to shift toward higher temperatures, as the ultrasound frequency grows. The results obtained can be satisfactorily explained in the framework of the Brailsford model, which associates the ultrasound absorption with vibrations of thermally activated dislocation kinks. The characteristic parameters of this model for p-Cd0.2Hg0.8Te are determined; namely, the frequency coefficient fk ≈ 6×10^9 Hz and the kink diffusion activation energy Wk ≈ 0.11 eV. The dislocation concentration is also evaluated (a ≈ 2×10^10 m^−2), with the determined value being consistent with that obtained by the selective etching method (0.7×10^10 m^−2).