Physical characteristics of Cu₂MgSnS₄ thin films synthesized using sol-gel dip coating technique for solar cell applications

In this study, Cu₂MgSnS₄ (CMTS) thin films have been prepared as a potential absorber layer in thin-film-based solar cells by the sol-gel method and deposited on ordinary glass substrates by the dip-coating technique. The as-prepared films have been characterised using a range of analytical techniques, including X-ray diffraction (XRD), Raman spectroscopy (RS), energy dispersive x-ray spectroscopy (EDS), a scanning electron microscope (SEM), a UV-visible spectrophotometer (UV), and a four-point probe technique (FPP). This comprehensive approach has enabled the investigation of their structural, optical, morphological, and electrical properties. The effect of annealing temperature on different Cu₂MgSnS₄ properties was also investigated at 350, 375 and 400 °C. XRD and RS results showed the formation of a polycrystalline structure with peaks corresponding to a single CMTS phase. Furthermore, annealing temperature showed variations in different CMTS properties. SEM micrographs indicated that the surface morphology of the samples is uniform with densely packed grains without any voids. Absorption coefficients were found to be larger than 104 cm⁻¹, with optical band gaps decreasing from 1.58 to 1.50 eV as the annealing temperature increases. The SCAPS-1D simulation tool was used to assess the performance of a CMTS-based solar cell using properties of CMTS annealed at 400 °C, as it showed good optical and electrical properties. The performance of this cell was evaluated by carefully changing the thickness, carrier density, defect density and working temperature. The experimental and numerical results of this study show that further investigations are needed to determine whether this material can be used as a potential absorber layer in thin film solar cells.