Optical properties and kinetic parameters in Cu2FeSnS4 thin films prepared by spray pyrolysis

The results of investigation of optical and electrical properties of p-Cu₂FeSnS₄ thin polycrystalline films obtained by spray pyrolysis of aqueous solutions of salts of CuCl₂∙2H₂O, FeCl₃∙6H₂O and SnCl₄∙5H₂O and (NH₂)₂CS are presented. On the basis of the analysis of the light absorption spectra, the optical band gap of the films E_g ≈ 1.72 eV was determined and the dynamics of its change during thermal treatment under low vacuum conditions (0.1 Pa). The conductivity activation energies (E_a = 0.75 eV) and the height of the energy barriers between the grain boundaries (E_b = 0.07 eV) are determined from the temperature dependences of the electrical conductivity.