AC conductivity properties of annealed In₂S₃ film deposited by spray technique

In₂S₃ thin film was prepared by chemical spray pyrolysis technique onto clean soda–lime glass substrate. Indium chloride and thiourea were used as reagents. This film was sealed into Pyrex tube at a pressure of 10⁻⁶ Torr and then annealed at 673 K for 3 h. The film was characterized by means of X-ray diffraction (XRD), atomic force microscope (AFM) and by impedance spectroscopy measurements. XRD spectra show that In₂S₃ film is polycrystalline with a cubic phase and preferentially oriented towards (400). The film grain size is about 45 nm. AFM analysis shows that root mean square (RMS) roughness is equal to 112 nm. The film electrical conductance is found to be dependent on measurement temperature and frequency. The direct current conductivity measurement outlines the dominance of the hopping mechanism. The alternating current electrical conductivity of the sample is controlled by the correlated barrier hopping conduction mechanism. The activation energy is found to be in the order of 90 meV. Furthermore, the film exhibits a photoconductive behavior.