DIELECTRIC PROPERTIES OF Co- And Yb-DOPED SINGLE CRYSTALS OF TlGaS2
Abstract
Electrical conductivity and dielectric properties of TlGaS2, TlGa0,999Yb0,001S2 and TlGa0,99 Co0,01S2 single crystals are investigated in the temperature range 150–320 K at the measuring field frequencies of 103 –106 Hz. The values of generalized activation energy of charge carriers in these crystals are determined. It is shown that the absolute values of the characteristics studied increase with temperature. The temperature dependences of the dielectric constant of these crystals have revealed the anomalies in the form of wide peaks, indicating the presence of their structural changes at temperatures ~ 170–250 K. The dispersion of the dielectric properties of the single crystals under study is seen: with a frequency growth the dielectric constant values decrease, and electrical conductivity values increase. It is found that the cobalt and ytterbium doping of TlGaS2 crystals decrease permittivity values and increase electrical conductivity values.