汎用原料を用いた Cu₂ZnSnS₄(CZTS) 薄膜太陽電池の紹介

抄録

  Cu₂ZnSnS₄ (CZTS) is one of the promising materials for low cost thin film solar cells, because of suitable band gap energy around 1.5 eV, and the large absorption coefficient over 10⁴ cm⁻¹. All constituents of this film are abundant on the crust of the earth, and they are not toxic. In 1996, we reported a fabrication process of CZTS films by sulfurization of EB evaporated precursors. We formed a new type of thin film solar cells having the structure of SLG/Mo/CZTS/CdS/ZnO: Al/Al and achieved the conversion efficiency of 0.66% for the first time. Recently, using CZTS compound target, we achieved over 6.4% efficiency with CZTS films prepared by the single sputtering followed by sulfurization. In this article, the development of CZTS-based thin film solar cells will be reviewed.