Preparation Of Cu₂ZnSnS₄ Films By Electrodeposition Using Reline Electrolyte

The composition of quaternary compound semiconduer Cu₂ZnSnS₄?CZTS? thin films are one of the most viable materials for low-cost, thin-film solar cells since they are produced from abundant materials, and have a band-gap energy of 1.45 eV and an absorption coefficient of over 104 cm-1? It has the concern of short availability of constituent elements?e.g. In, Ga? which limits its development.In our study, the CZTS precursor was electrochemically deposited by Reline electrolyte as the electrolyte. After annealing and sulfurization of the precursor, CZTS thin film was obtained. And the experimental parameters in annealing and sulfurization, such as temperature and duration, was studied for the impact of the properties of the film. The study was mainly on three parts:The first part of the work was the study of the electrochemical properties of the Reline electrolyte systematically, and its electrodepositon condition for the CZTS precursor deposition. For the CZTS solar cell, the CZTS film is the absorption layer, the quality and composition of which plays an important role in the solar cell performance. In our experiments, different deposition volt was adapted to study its impact on the precursor composition. Finally, we made CZTS precursor with proper composition ratio.The second part of the work was the annealing of the CZTS precursor. By controlling the temperature and duration during annealing, the effect of the temperature and the duration on morphology and composition was studied. The composition was measured by XRF at different deposition condition, then the optimal condition was obtained. At last, the XRD measurement was conducted on the best precursor, validated the fact that the alloying of the precursor during the annealing process.The third part of the work was the sulfurization of the annealed precursor in order to obtain the CZTS film, and sulfur powder was selected as sulfur source. Different sulfurization temperature was adapted to observe its impact on the film morphology and compostion. Raman measurements was conducted to confirm the formation the CZTS crystallization. For the sulfurization process was performed at high temperature, the insufficient of Tin was found in the final film. The volatilization of Sn was very common in sulfurization, which was also found in our study. Therefore, the mechanism of the volatilization of Sn still requires further investigation.