Deposition temperature effect on the electric and dielectric properties of InSbSe 3 thin films

Abstract

Thin films of InSbSe 3 compound were obtained by thermal evaporation on to clean glass substrates maintained at various deposition temperatures from 423 to 593 K. At deposition temperature T d⩽473 K, the films have an amorphous structure, while those prepared at T d>473 K have a polycrystalline structure identified by X-ray diffraction analysis. The DC electrical conductivity of the films increases as T d increases, whereas activation energy decreases with increasing T d, which reflects a change in the degree of disorder. AC conductivity was studied as a function of frequency in the range (10 2–10 5 Hz) and as a function of deposition temperature. The dependence of T d on the frequency exponent s in the conductivity–frequency relation confirmed that the mechanism of AC conductivity is correlated barrier hopping with a single polaron hopping mechanism. The discrepancy between DC and AC activation energies was studied as a function of deposition temperature. The maximum barrier height W m and the density of defect states N were also determined. Finally, the dependence of dielectric constant and dielectric loss on T d were studied. A Debye-like relaxation of dielectric behavior was observed for crystalline films and is found to be a thermally activated process. The position of maximum dielectric loss is shifted towards higher temperature with T d treatment and there by reduces the relaxation time.