Low-temperature spray-pyrolysis of FeS2 films and their electrical and optical properties

Abstract

Iron disulfide (FeS₂) films with a wide range of electrical resistivities 100 Ω cm ⩽ ρ ⩽ 800 kΩ cm, a high adhesion to the substrate, and a resistance to aggressive media have been prepared by the spray pyrolysis of aqueous solutions of the salts FeCl₃ · 6H₂O and (NH₂)₂CS at low temperatures in the range 250°C ⩽ T_S ⩽ 400°C. It has been found that the FeS₂ films have a high transmittance T ≈ 60–70% and are characterized by a sharp transmission edge. It has been shown that the optical band gap for direct (E_g^op = 2.19–2.78 eV) and indirect (E_g^′op = 1.26–1.36 eV) optical transitions depends on the conditions of film preparation.