Structural development and dynamic process in sulfurizing precursors to prepare Cu2ZnSnS4 absorber layer

• CZTS films were fabricated by sulfurizing the fabricated precursor films.
• Annealing time and temperature are very important for synthesis of pure CZTS films.
• Pure CZTS films with high quality can prepared at 500 °C and 90 min.
• Both high temperature and long heating time causes the decomposition of CZTS films.

Cu2ZnSnS4 (CZTS) films were fabricated by sulfurizing the fabricated metal-precursor films under sulfur atmosphere. All samples prepared at different conditions were characterized by X-ray diffraction, Raman scattering measurements, scanning electron microscopy, energy dispersive X-ray spectroscopy, and UV spectrophotometer. We systematically studied the influence of sulfurization time and temperature on structures, morphologies, compositions, and optical properties, and analyzed deeply the transformation of structural phase and dynamic process during the formation process of CZTS films. Experimental results indicate that the proper sulfurization time and temperature play an important role in synthesizing pure CZTS films with high quality. Compared with the others, the prepared sample at 500 °C and 90 min shows uniform surface morphology, excellent crystal quality, and optical properties. Various growth conditions realize the modulation of structure, impurity phase, morphology and optical properties. The present research results are helpful for us to deeply understand the growth process of CZTS film and pave the way for realizing the fabrication of high quality CZTS absorption layer.