Effect of thickness and sulfur-free annealing atmosphere on the structural, optical and electrical properties of Cu 2 ZnSnS4 thin films prepared by dip-coating technique

Cu2ZnSnS4 thin films were prepared by dip-coating technique and annealed in N2 atmosphere. The effect of thickness and annealing temperature on structural, optical and electrical properties of Cu2ZnSnS4 thin films in the temperature range 400–540 °C were investigated. X-ray diffraction patterns corresponding to (112), (220) and (116) planes revealed that all Cu2ZnSnS4 thin films exhibited kesterite structure. Additionally, tetragonal kesterite phase of Cu2ZnSnS4 thin films was also confirmed with a strong 334 cm−1 peak using Raman spectroscopy. The results of Raman spectra, X-ray diffraction patterns and UV–Vis spectra indicated that 600 nm thick Cu2ZnSnS4 thin film at 450 °C showed kesterite phase and an excellent optical absorption coefficient over 105 cm−1 in visible region. Furthermore, the effect of annealing temperature on the presence of secondary phases was also clarified. Using the Cu2ZnSnS4 thin film as p-type thin film, p-Cu2ZnSnS4/n-Si (100) hetero-junction was prepared successfully with a good rectification behavior. Graphical Abstract CZTS thin films were prepared by dip-coating technique and annealed in N2 atmosphere. The effect of thickness and annealing temperatures on the quality of CZTS thin films were clarified. The results showed that CZTS thin films exhibited kesterite phase and an excellent optical absorption coefficient over 105 cm−1 in visible region. As annealing temperature increase above 450 °C, the presence of Cu2-xS secondary phase significantly affected the quality of CZTS. [InlineMediaObject not available: see fulltext.]