Effect of sulfurization temperature on the surface roughening, electrical and optical properties of FeS2 films deposited by sol–gel method

FeS2 films were prepared by sulfurizing precursive Fe2O3 films at different temperatures. The structural and photoelectrical characters were determined. According to these results, precursive Fe2O3 sulfurized at temperatures 400–600 °C could transform into FeS2 films. The RMS roughness decreases in the low temperature period from 300 to 400 °C and then increases by further increasing the temperature. The changes of surface roughness can be attributed to the different interactions of surface energy and interface energy at different sulfurization temperatures. The optical and electrical properties of the films depend mainly on the changes of the density of crystal defects and the microstructure. With the sulfurization temperature increasing, the optical absorption coefficient and band gap decrease while the electrical resistivity increases.

AFM morphologies of the pyrite films prepared at different sulfurization temperatures: (a) 300 °C, (b) 400 °C, (c) 500 °C and (d) 600 °C. See the text for further illustration.Figure optionsDownload as PowerPoint slideHighlights
► FeS2 films were synthesized by sol–gel dip-coating method.
► Thermal roughening appears at high temperature regime while kinetic roughening (atoms migrate slowly) occurs at low temperature regime.
► The optical and electrical properties of the films depend mainly on the changes of the density of crystal defects and the microstructure.
► With the sulfurization temperature increasing, optical absorption coefficient and band gap decrease while the electrical resistivity increases.