Investigation of physical properties and impedance spectroscopy study of Cu3SbS3 thin films

Cu3SbS3 ingot material was successfully grown by direct melting of the constituent elements taken in stoichiometry compositions using high-purity copper, antimony and sulfide elements. Cu3SbS3 thin films were prepared by single source vacuum thermal evaporation method under vacuum (10−5 Torr) onto no heated glass substrates. The X-ray diffraction experimental data revealed that the Cu3SbS3 powder exhibiting an orthorhombic structure and lattice parameters a, b and c were calculated. It has been shown that the as-deposited Cu3SbS3 thin films were overall amorphous and the film thicknesses were around 400 nm. The absorption spectra of the films showed that the Cu3SbS3 compound is a direct band gap material and the gap value is closed to 1.46 eV. The as-deposited Cu3SbS3 films show absorption coefficients of about 2 × 105 cm−1 near the absorption edge. The as-deposited Cu3SbS3 films exhibit p-conductivity type by using hot probe method. A Schottky diode (Al/p-Cu3SbS3/Mo) was fabricated by simple deposition of pure Aluminum on the front side of the Cu3SbS3 thin film. I–V characteristics show that the Al makes Schottky contact with p-Cu3SbS3. Impedance spectroscopy technique was used to evaluate the conduction processes of the samples as a function of temperature (598–673 K) in the range 1 Hz–13 MHz. We found a decrease with temperature of the entire serial resistance Rs, the parallel resistance Rp and the capacitance Cp. In effort to modeling these results an equivalent electrical circuit was used. From the Arrhenius diagram, we estimated activation energy at 0.16 eV which represents the energy difference between the trap level and the valence band.