Effect of the Chemical Composition of TlIn1 – xErxS2 (0 ≤ x ≤ 0.01) Crystals on Their Dielectric Characteristics and the Parameters of Localized States.

The frequency dependences of the real (ε') and imaginary (ε'') parts of the complex dielectric permittivity, the dielectric loss tangent (tanδ), and the ac conductivity (σac) in the frequency range f = 5 × 104–3.5 × 107 Hz have been studied in the TlIn1 –xErxS2 (0 ≤ x ≤ 0.01) crystals synthesized in this work. It is found that, in TlIn1 –xErxS2, the relaxation dispersions of ε' and ε'' take place. The effect of the erbium concentration (Er) in the TlIn1 –xErxS2 crystals on their dielectric coefficients has been studied. At high frequencies, the ac conductivity of the TlIn1 –xErxS2 crystals obeys the relationship σac ~ f 0.8, which is characteristic of the hopping mechanism of the charge transfer over states localized near the Fermi level. The parameters of the states localized in the forbidden band of TlIn1 –xErxS2 and the influence of the chemical composition of the crystals on these parameters are estimated. [ABSTRACT FROM AUTHOR]