Deposition temperature effect on the electric and dielectric properties of InSbSe3 thin films

Thin films of InSbSe3 compound were obtained by thermal evaporation on to clean glass substrates maintained at various deposition temperatures from 423 to 593 K. At deposition temperature Td⩽473 K, the films have an amorphous structure, while those prepared at Td>473 K have a polycrystalline structure identified by X-ray diffraction analysis. The DC electrical conductivity of the films increases as Td increases, whereas activation energy decreases with increasing Td, which reflects a change in the degree of disorder. AC conductivity was studied as a function of frequency in the range (102–105 Hz) and as a function of deposition temperature. The dependence of Td 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 Wm and the density of defect states N were also determined. Finally, the dependence of dielectric constant and dielectric loss on Td 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 Td treatment and there by reduces the relaxation time.