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Electronics and Telecommunications Research Institute (한국전자통신연구원)
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Interface Analysis of Cu(In,Ga)Se2 and ZnS Formed Using Sulfur Thermal Cracker

  • Cho, Dae-Hyung (ICT Materials & Components Research Laboratory, ETRI) ;
  • Lee, Woo-Jung (ICT Materials & Components Research Laboratory, ETRI) ;
  • Wi, Jae-Hyung (ICT Materials & Components Research Laboratory, ETRI) ;
  • Han, Won Seok (ICT Materials & Components Research Laboratory, ETRI) ;
  • Kim, Tae Gun (Korea Research Institute of Standards and Science and also with Korea University of Science and Technology) ;
  • Kim, Jeong Won (Korea Research Institute of Standards and Science and also with Korea University of Science and Technology) ;
  • Chung, Yong-Duck (ICT Materials & Components Research Laboratory, ETRI)
  • Received : 2015.07.31
  • Accepted : 2016.02.18
  • Published : 2016.04.01
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Abstract

We analyzed the interface characteristics of Zn-based thin-film buffer layers formed by a sulfur thermal cracker on a $Cu(In,Ga)Se_2$ (CIGS) light-absorber layer. The analyzed Zn-based thin-film buffer layers are processed by a proposed method comprising two processes - Zn-sputtering and cracker-sulfurization. The processed buffer layers are then suitable to be used in the fabrication of highly efficient CIGS solar cells. Among the various Zn-based film thicknesses, an 8 nm-thick Zn-based film shows the highest power conversion efficiency for a solar cell. The band alignment of the buffer/CIGS was investigated by measuring the band-gap energies and valence band levels across the depth direction. The conduction band difference between the near surface and interface in the buffer layer enables an efficient electron transport across the junction. We found the origin of the energy band structure by observing the chemical states. The fabricated buffer/CIGS layers have a structurally and chemically distinct interface with little elemental inter-diffusion.

Keywords

References

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