[10a-PB3-1~14] 13.9 Compound solar cells

[10a-PB3-7] Preparation of Cu₂Sn_1-xGe_xS₃ thin film by sol-gel sulfurization method

〇Kyouhei Yamamoto¹, Kunihiko Tanaka¹ (1.Nagaoka Univ. of Tech)

Keywords:Cu2Sn1-xGexS3

Band gap energy of the Cu₂SnS₃ (CTS) can be increased by substituting of a part of Sn with Ge, Cu₂Sn_1-xGe_xS₃ (CTGS), from 0.84 to 1.54 eV, and therefore the band gap energy can be adjusted to suitable value for solar cell’s absorption layer of ~1.5 eV. In this study, CTGS thin film was deposited by sol-gel sulfurization method which has been known as a low cost and non-vacuum process in order to reduce production cost. A Cu-Sn-Ge (CTG) coating solution was prepared from Cu acetate, Sn chloride and Ge oxide dissolved into 2-methoxyethanol and pure-water as solvents. CTG precursors were fabricated by coating the solution. The prepared precursors were sulfurized a H2S containing atmosphere. All sulfurized samples showed a XRD peak which shit from CTS (200) to CGS (200) side and the peak was attributed to CTGS (200). The XRD from the sample sulfurized at 400°C showed a peak attributed to CuS, and the XRD from the sample sulfurized at 500°C showed a CGS (200) peak in addition to CTGS (200). The sample sulfurized at 600°C showed only peaks attributed to CTGS with the shifting diffraction angle of 0.4°, chemical composition ratio of Ge/(Ge+Sn) is ~0.5.