Fabrication of High Quality Bornite and Chalcopyrite Thin Films by Aerosol-Assisted Chemical Vapor Deposition

Recently, several transition metal chalcogenide materialswithfavorable optical and electrical properties suitable for sustainablesolar-based energy generation have been identified. In this work,thin films of two promising ternary sulfides (bornite and chalcopyrite)in the Cu-Fe-S system were successfully synthesizedas thin films from utilizing tris-N,N-diethyldithiocarbamate iron(III) and bis-N,N-diethyldithiocarbamate copper(II) molecular precursorsin aerosol-assisted chemical vapor deposition at 450 & DEG;C for 1h. The deposited thin films were studied by powder X-ray diffraction,and the resulting patterns were indexed to orthorhombic and tetragonalcopper iron sulfide (bornite, Cu5FeS4 and chalcopyrite,CuFeS2). The morphology of the films at the microscalewas explored by scanning electron microscopy, revealing a polycrystallinethin film with elemental ratios (i.e., Cu:Fe:S) of the two materialscorresponding to those expected for bornite (& AP;5:1:4) and chalcopyrite(& AP;1:1:2), consistent with the X-ray structural characterization.Characterization of the electrical transport properties of these high-qualitythin films by the four-point probe method was performed. The resultsrevealed resistivities of 1.8 x 10(-4) & omega;& BULL;mfor bornite and 1.6 x 10(-2) & omega;& BULL;m forchalcopyrite, which are consistent with previously reported valuesfor the bulk materials. Estimation of the optical energy band gapfrom Tauc plots of the ultraviolet-visible spectroscopy data was takenfor bornite and chalcopyrite giving direct band gap energies of 1.28and 0.97/1.62 eV, respectively, demonstrating their potential utilityas either solar absorbing thin films or for photocatalysts for watersplitting.

Automated summary

Recently, favorable transition metal chalcogenide materials for sustainable solar-based energy generation have been identified. In this study, thin films of two promising ternary sulfides in the Cu-Fe-S system were successfully synthesized through chemical vapor deposition. The films exhibited the expected crystal structures and elemental ratios, with electrical and optical properties consistent with their potential applications in solar energy conversion and photocatalysis.