Cu₂Si_xSn_1−xS₃ Thin Films Prepared by Reactive Magnetron Sputtering For Low-Cost Thin Film Solar Cells

We report the preparation of Cu₂Si_xSn_1−xS₃ thin films for thin film solar cell absorbers using the reactive magnetron co−sputtering technique. Energy dispersive spectrometer and x-ray diffraction analyses indicate that Cu₂Si_1−xSn_xS₃ thin films can be synthesized successfully by partly substituting Si atoms for Sn atoms in the Cu₂SnS₃ lattice, leading to a shrinkage of the lattice, and, accordingly, by 2θ shifting to larger values. The blue shift of the Raman peak further confirms the formation of Cu₂Si_xSn_1−xS₃. Environmental scanning electron microscope analyses reveal a polycrystalline and homogeneous morphology with a grain size of about 200–300 nm. Optical measurements indicate an optical absorption coefficient of higher than 10⁴ cm⁻¹ and an optical bandgap of 1.17±0.01 eV.