Structure and dielectric behavior of TlSbS2

Abstract

A comparison of structure and dielectric properties of TlSbS2 thin films, deposited in different thicknesses (400-4100 ) by thermal evaporation of TlSbS2 crystals that were grown by the Stockbarger-Bridgman technique and the bulk material properties of TlSbS2 are presented. Dielectric constant epsilon (1) and dielectric loss epsilon (2) have been calculated by measuring capacitance and dielectric loss factor in the frequency range 20 Hz-10 KHz and in the temperature range 273-433 K. It is observed that at 1 kHz frequency and 293 K temperature the dielectric constant of TlSbS2 thin films is epsilon (1)=1.8-6 and the dielectric loss of TlSbS2 thin films is epsilon (2)=0.5-3 depending on film thickness. In the given intervals, both of dielectric constant and dielectric loss decrease with frequency, but increase with temperature. The maximum barrier height W (m) is calculated from the dielectric measurements. The values of W (m) for TlSbS2 films and bulk are obtained as 0.56 eV and 0.62 eV at room temperature, respectively. The obtained values agree with those proposed by the theory of hopping over the potential barrier. The temperature variation of ac conductivity can be reasonably interpreted in terms of the correlated barrier hopping model since it obeys the omega (s) law with a temperature dependent s (s < 1) and going down as the temperature is increased. The temperature coefficient of capacitance (TCC) and permittivity (TCP) are evaluated for both thin films and bulk material of TlSbS2.