Investigation of electrical and dielectric properties of antimony oxide (Sb2O4) semiconductor thin films for TCO and optoelectronic applications

Abstract

This work presents some electrical properties based on the impedance measurements as well as the dielectric constants on thermal evaporated Sb2O4 thin films additional to structural, opto-thermal and optical investigations which are reported previously by Ouni et al. in Journal of Non-Crystalline Solids (vol. 356 (2010) 1294–1299). The electrical conductivity and dielectric properties of Sb2O4 thin film were indeed studied using impedance spectroscopy technique in the frequency range 5Hz–13MHz at various temperatures (325–450°C). The complex impedance diagram at different temperatures showed a single semicircle, implying that the response originated from a single capacitive element corresponding to the grains. AC and DC conductivities were studied to explore the mechanisms of conduction. It can be seen from the experimental data that the AC conductivity in thin films of Sb2O4 is proportional to ωs (s<1), the value of s is to be temperature-dependent, which has a tendency to decrease in temperature. The temperature dependence of both AC conductivity and the parameter s is reasonably well interpreted by the correlated barrier hopping (CBH) model. Values of dielectric constants ε1 and ε2 were found to decrease with frequency and increase with temperature. Activation energy values deduced from both DC conductivity and relaxation frequency are of the order of Ea~0.7eV. The analysis of the parameter s leads to the barrier height Wm value which is in agreement with that proposed by the theory of hopping of charge carriers over the potential barrier between the defect states in the band tail as suggested by Elliott.