In this work, thin films of phase-pure Cu₂ZnSnS₄ (CZTS) were developed from a stack of binary metal sulfides by post-deposition thermal processing. The precursor stack SnS/Cu/ZnS was grown by sequential electrodeposition of SnS and Cu layers followed by thermal evaporation of ZnS layer. The transformation from binary/ternary composition to phase-pure CZTS was studied using different experimental tools such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The TEM images revealed the formation of tetragonal crystals with interplanar spacing 0.312 nm. Raman spectra of the films confirmed that annealing at 550°C for 30 min under N₂/S ambient resulted in the formation of phase-pure CZTS film. The bandgap estimated from the optical transmittance and reflectance spectra showed a direct transition at 1.59 eV. The films are photosensitive and the photo electrochemical measurements showed the p-type conductivity of the films.

A numerical simulation is a valuable tool since it allows the optimization of both time and the cost of experimental processes for time optimization and the cost of experimental processes. In addition, it will enable the interpretation of developed measurements in complex structures, the design and optimization of solar cells, and the prediction of the optimal parameters that contribute to manufacturing a device with the best performance. In this sense, a detailed simulation study was carried out in this work by the Solar Cell Capacitance Simulator (SCAPS). In particular, we evaluate the influence of absorber and buffer thickness, absorber defect density, work function in back contact, R_s, R_sh, and carrier concentration on a CdTe/CdS cell to maximize its performance. Furthermore, the incorporation effect of ZnO:Al (TCO) and CuSCN (HTL) nanolayers was studied for the first time. As a result, the efficiency of the solar cell was maximized from 16.04% to 17.74% by increasing the J_sc and V_oc. This work will play an essential role in enhancing the performance of CdTe-based devices with the best performance.