Investigation and optimization of an effective fabrication process to develop a high-quality CZTS thin layer for photovoltaic applications

Despite its outstanding advantages, its relatively low practical efficiency has prevented CZTS from replacing CIGS. The most important reason for this drawback is known to be the poor crystallization and high porosity of the produced CZTS thin films, causing defect-related recombination. In this work, an organic-based sol-gel method has been used to develop CZTS thin films and several parameters have been examined to optimize the developed thin film quality. Controlled parameters include the molar ratio of precursor solution, drying atmosphere of the samples, thermal annealing, and sulfurization concurrent to thermal annealing. The effect of each parameter was experimentally evaluated using the produced samples' structural, morphological, optical, and electrical characterization. The experimental details of the synthesis and post-processing procedures are presented in addition to the results of performed characterizations such as XRD, UV–vis, Raman spectroscopy, SEM micrographs, EDS analysis, and sheet resistance, which are discussed in this article. Finally, the optimized thin film's response to different wavelengths was evaluated and exhibited an excellent response to the applied wavelengths. The findings of this study would be useful in the development of high-quality CZTS thin films for photovoltaic applications.