Characterization of FeS2-pyrite thin films synthesized by sulphuration of amorphous iron oxide films pre-deposited by spray pyrolysis

• Published in: Materials characterization Vol. 54; no. 4-5; pp. 431 - 437
• Main Authors: OUERTANI, B, OUERFELLI, J, SAADOUN, M, BESSAIS, B, EZZAOUIA, H, BERNEDE, J. C
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Science 01.05.2005
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Solidification; Pyrolysis; 61.66.Fn; 68.37.Hk; Spray pyrolysis; Electrical properties; Oxide layer; Sulphuration; Spray coatings; Iron oxide (Fe2O3); Thin films; 61.10.Nz; Pyrite; 78.40.Fy Thin films; Optical properties; 61.50.Nw; Oxidation; Iron oxides; FeS2
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2005.01.009

FeS2--thin films with good crystallinity were synthesized by a simple method which consists of sulphuration, under vacuum, of amorphous iron oxide thin films pre--deposited by spray pyrolysis of FeCl3*6H2O (0*03 M)--based aqueous solution onto glass substrates heated at 350 deg C. At optimum sulphuration temperature (450 deg C) and duration (6 h), black green layers having granular structure and high absorption coefficient (~5*10(4)cm(--1)) were obtained. The study of the electrical properties of the as--prepared films vs. the temperature variations showed three temperature domain dependence of the conductivity behaviour. The first one corresponds to the high temperature range (330 K--550 K) for which an Arrhenius plot type was obtained. The activation energy value was estimated at about 61*47 meV. The second domain corresponding to the intermediate temperature range (80 K--330 K) showed a variable activation energy between the grain boundaries. The barrier height, q*f*?, was estimated to 27+/--0*5 meV, and the standard deviation, qsigma*f, was evaluated at about 14+/--0*5 meV. We found that at lower temperatures (20 K--80 K), the conductivity is governed by two conduction types. The density of localised states, was about 2*45x10(2)(0)eV(--1)cm(--3).