Rapid thermal sulphurisation of Cu-rich and Cu-poor Cu-In precursors for the production of CuInS2 layers for photovoltaic applications: a microstructural study

For the formation of CuInS₂ absorber layers, Cu-rich and Cu-poor Cu-In precursor layers have been deposited on Mo-coated glass slides and annealed in a rapid thermal process at 500°C with elemental sulphur. Samples taken at different stages of the sulphurisation process have been analysed by transmission electron microscopy (TEM) and energy dispersive X-ray microanalysis (EDX), in combination with X-ray diffraction (XRD), Raman scattering and Auger electron spectroscopy (AES). The formation of CuInS₂ has been detected before reaching 500°C and complete sulphurisation occurs at 120s for both samples. Secondary phases are CuS in the Cu-rich case and CuIn₅S₈ and β-In₂S₃ for the Cu-poor sample.