Preparation Of Absorbing Layer Of Copper - Zinc - Sn - Sn Film Solar Cell By Magnetron Sputtering

In recent years, people pay more and more attention to the use of photovoltaic about solar radiation. CZTS thin film solar cells with low cost, high conversion efficiency and absorption coefficient, appropriate band and non-toxicity have become research focus of thin film solar cells in recent years.In this paper, CZTS thin films prepared by magnetron sputtering were studied. The composition, crystal structure, surface morphology and optical properties of the CZTS thin films were characterized by X-ray diffraction, Micro Raman spectroscopy, scanning electron microscopy(SEM) and ultraviolet visible spectrophotometer(UV-VIS), the relationship between critical parameters(sputtering pressure, sputtering power of copper, vulcanization temperature and vulcanization time) and the properties of CZTS thin films were investigated systematically, optimized parameters of the sputtering process for better performance of CZTS thin films were obtained.Besides, CZTS powders were prepared by solid phase reaction method successfully, the effect of sintering temperature on the sample composition and phase structure were studied, and the morphology and optical properties of the powder were characterized.The dissertation’s main results are as follows:(1) Cu2 Zn Sn S4(CZTS) thin films were successfully fabricated by alloying and sulfurizing CZT precursors on coating-Mo glass substrate. the influence of the sputtering pressure on the properties of CZTS thin films were studied. When the sputtering pressure is 0.3Pa, the thin film components close to the demand of the CZTS thin film solar cell absorption layer, and the film is uniform and dense, the adhesion is good. The influence of sputtering power of copper on the properties of CZTS thin films were studied. When sputtering power of copper is 70 W, the film is dense, and the adhesion is good.(2) Higher sulfurization temperature and sulfurization time promoted the sputtered particles to crystallize and grow on the substrate, leading to improving the crystalline quality of the films, and the optical properties of the films could be enhanced. when sulfuration temperature is 530℃ and sulfuration time is 15 min, the film is dense, the adhesion is good, and the absorbance is high. Optimized sputtering parameters and sulfuration parameters are obtained. the sputtering pressure is 0.3Pa, the sputtering power of Cu is 70 W, the sulfuration temperature is 530℃, and the sulfuration time is 15 min.(3) Cu2 Zn Sn S4 powder materials were prepared by the solid state reaction method. the powders contained Cu S impurity phase when the sintering temperatures are 400℃ and 450℃. The pure CZTS powders were prepared while the annealing temperature is above 500℃.The atomic ratios Cu/(Zn+Sn) and Zn/Sn are close to 1, consistent with the stoichiometric composition, as-obtained CZTS powders have obvious absorption in the visible light, and the band gap, is about 1.51 e V. Combining with the parameters of the solid state reaction method, Optimized parameters are obtained: the annealing temperature is 550℃, and the annealing time is 30 h.