Investigation of optimum annealing parameters for formation of dip coated Cu₂ZnSnS₄ thin film

Cu₂ZnSnS₄ (CZTS) is most attractive absorber material for inorganic solar cell applications because of its cost effective and ecofriendly nature. To obtain phase pure CZTS film, effects of annealing parameters on synthesis of CZTS thin film are investigated. CZTS films are deposited through dip coating method followed by heat treatment to form crystalline CZTS thin films. Factors influencing the crystallinity, morphology and composition of the films such as annealing temperature, time, rate and atmosphere are studied through X-Ray Diffraction, Raman Spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy. After numerous experiments of synthesis of CZTS in different annealing conditions and its characterization, it is observed that 1.4 eV band gap CZTS thin film of kesterite structure is obtained by annealing the film in nitrogen atmosphere for 60 min at 300 °C with 10 °C/min ramping rate. - Highlights: • Dip coated Cu₂ZnSnS₄ film is developed using non-hydrazine based precursor solution. • Optimum annealing condition to achieve best crystalline film is studied. • Optimal condition is 300 °C in N₂ atmosphere for 60 min at 10 °C/min ramping rate. • Bandgap of prepared films is 1.4 eV, suitable for solar cell applications.