AC conduction and current voltage characteristics of (Sb2Se3)2 (Sb2Te3)1 thin films

Abstract

Amorphous thin films of (Sb2Se3)2(Sb2Te3)1 are prepared by the thermal evaporation of the studied composition on glass substrates. The differential thermal analysis (DTA) with four different heating rates α = 15, 20, 25 and 30 °C/min are recorded for the studied sample in powder form under non-isothermal condition. Dielectric properties and AC conduction at temperature range (303–373 K) and frequency range (102–105Hz) are studied for the investigated composition in thin film form. AC conductivity obeys the law σac(ω) = A ωs where s is the frequency exponent, ω is the angular frequency, s < 1 and s inversely proportion to temperature. The suitable mechanism of conduction is the correlated barrier-hopping (CBH) model between random close pairs of centers (NVAP,s). The dielectric loss ε2 and dielectric constant ε1 are dependent on temperature and frequency. The value of maximum barrier height WM calculated using Guintini equation and is in agreement with the hopping theory of Elliott in chalcogenide glasses. The change of dielectric constant with temperature is investigated also. The current—voltage characteristics are ohmic in the low field region followed by non-ohmic region in the high field region which is explained by the Poole–Frenkel effect.