Parametric Study of Copper Zinc Tin Sulfide Thin Films by Convective Deposition Method

Abstract

Nowadays, most of the energy production is from fossil fuel-resources, which is a major source of greenhouse gases. Therefore, several researchers have been looking for the alternative energy that is clean and renewable energy. One of the outstanding alternatives is to utilize solar energy for conversion into electricity. Recently, CZTS (copper zinc tin sulfide, Cu2ZnSnS4) thin film solar cells have received numerous interest because of its decent energy band gap of about 1.4 – 1.6 eV, which matches with the solar spectrum, and its high absorption coefficient. Nevertheless, the manufacture of CZTS solar cells has used sophisticated methods for fabrication including CZTS which is an absorber layer. Therefore, this work was aimed to use the solution-based convective deposition method for fabrication of CZTS thin films due to its simplicity and low-cost yet effective. The focus of this work was to investigate the effects of various deposition parameters including deposition speed, types of solvent (2-methoxyethanol and deionized water) and fraction of solvents on the physical properties of CZTS films. According to the experimental results, higher deposition speed led to small grains of CZTS in the films. Moreover, CZTS film prepared from a solvent with higher fraction of deionized water resulted in a compact film. On the contrary, the film prepared from a solvent with pure 2-methoxyethanol resulted in porous film. This desired compact CZTS film was proved to show a better performance (higher efficiency) of CZTS solar cell. As a consequence, it could be confirmed that a desired morphology of CZTS thin films could be obtained under a controlled deposition condition. Furthermore, convective deposition can be a potential method for fabrication of thin films for various applications.