[21a-B202-1~11] 13.9 Compound solar cells

[21a-B202-9] Electronic structure of CIS/Mo back interface in CIS Solar cells

〇Kohei Hamashiri¹, Tsubasa Imanishi¹, Yu Miyanohara¹, Oki Kozima¹, Motoya Ohba¹, Takuya Kato², Yoshinori Kimoto², Syogo Ishiduka³, Jiro Nishinaga³, Hajime Shibata³, Yukiko Kamikawa³, Norio Terada¹ (1.Kagoshima Univ., 2.Idemitsu Kosan Co.Ltd., 3.AIST)

Keywords:CIS Solar cells

For determining the band alignment at the interface between the back surface of Cu(In,Gs)(S,Se)₂(CIS) absorber and the surface of Mo back electrode in the CIS-based solar cell, the back surface of the CIS and the surface of the Mo exposed by means of lift-off in UHV were characterized by means of in-situ direct and inverse photoemission spectroscopy and Kelvin probe microscopy. The experiments have revealed that the surface of the Mo electrode is covered with Mo-dichalcogenide layer with a work function higher than that of the back surface of the CIS. On the other hand, the work function of the metallic region of the Mo electrode is lower by about 1.0 eV than that of the surface. These results indicate that an upward band bending presents in the CIS-side interface and a large hole barrier exists between the surface and metallic region of the Mo electrode. The latter indicates that the tunnel conduction is a domination mechanism of the hole transportation in the CIS/Mo interface.