https://doi.org/10.15407/jopt.2017.52.108

Optoelectron. Semicond. Tech. 52, 108-122 (2017)

Ya.M. Olikh, M.D. Tymochko, N.V. Safriuk, M.I. Ilashchuk1, O.Ya. Olikh2

ІNVESTIGATIONS OF NEAR DISLOCATION CLUSTERS OF POINT DEFECTS IN CdZnTe CRYSTALS BY USING THE HALL METHOD UNDER THE ULTRASOUND LOADING THE CRYSTALS

Temperature dependences (77…300) K of the electron concentration n(T) and mobility µH(Т) were studied by using the “acousto-Hall method” (Hall method under ultrasound loading the crystals) to find out mechanisms of ultrasound influence on electrical activity of near-dislocation clusters in n-type low-ohmic CdZnTe single crystals (NCl ≈ 1024 m–3) of different dislocation density (0.4…5.1)·1010 m–2. The electrical parameter changes depending on temperature and ultrasound intensity were found out. In order to evaluate relative contribution of different charge carrier mechanisms of scattering (by lattices, ionized impurity, neutral impurity and dislocations), as well as their changes under ultrasound loading, the differential evolution method was used. The method made it possible to analyze experimental dependences µH(Т) by their nonlinear approximation with account of characteristic temperature dependences of µH for each mechanism. It has been ascertained the increase in scattering by neutral impurity and decrease in components of scattering by ionized impurities and dislocations were observed during the ultrasound loading. The character and magnitude of these acousto-induced changes correlate with dislocation characteristics of particular samples. It has been concluded that the observed effects are related to the acousto-induced transformation of the point-defect structure, mainly in the near-dislocation regions of crystals.

Keywords: ultrasound, CdZnTe crystals, point defects, dislocation clusters, Hall effect.