[26p-F408-1~11] 16.3 Bulk, thin-film and other silicon-based solar cells

△ [26p-F408-5] Investigation of the IWO Film Deposition Conditions for the Bottom Cell in Tandem Solar Cells

〇SHIYU ZHANG¹, Tappei Nishihara¹, Hyunju Lee^1,3, Yoshio Ohshita², Atsushi Ogura^1,3 (1.Meiji University, 2.Toyota Tech. Inst., 3.Meiji Renewable Energy Institute)

Keywords:IWO films, TCO, Tandem Solar Cells

In crystalline Si solar cells as bottom cells used in high-efficiency tandem solar cells, the transparent conductive film (TCO) is required to have high transmittance in the NIR region (900-1200 nm). Especially on the rearside, a relatively thick film is used to obtain good reflectivity. The common TCO, ITO (indium oxide doped with a few percent of tin), has a large optical loss due to free carrier absorption (FCA) in the NIR region, so alternative materials are being explored. IWO film, which is In₂O₃ doped with tungsten, has high transmittance in the NIR region while maintaining the same resistivity as ITO. In this paper, the effects of transmittance for O₂/Ar flow ratio and annealing temperature on the IWO films in the NIR region are investigated.