[14a-PA5-1~23] 13.9 Compound solar cells

[14a-PA5-12] Effect of optical properties on sodium doped SnS-related thin films

〇Keina Kusatsu¹, Khatri Ishwor², Joonam Kim^1,2, Mutsumi Sugiyama^1,2 (1.Tokyo Univ. of Sci., 2.RIST TUS)

Keywords:SnS, Na doping, Photoluminescence

Tin sulfide (SnS) thin film composed by tin (Sn) and sulfur (S) which are abundant in the crust and inexpensive elements, has high light absorption coefficient over 10⁴cm^-1 and a band gap of 1.3 eV. However, the currently reported maximum SnS solar cells efficiency is 4.8%, which is lower than the theoretical conversion efficiency. There are expected reasons such as S re-evaporation during high-temperature growth and formation of SnS₂ or Sn₂S₃ having n-type conductivity. In general, for CIGS and CZTS which are Cu-based compound semiconductors, it has been reported that the addition of Na improves the properties for a solar cell caused by increasing the carrier density and suppressing grain boundaries. Although it is known that the crystal quality and the solar cell characteristics of SnS are improved by Na doping, there are few reports on the effect of Na on SnS. In this study, the relationship between defects and optical properties was examined by a Photoluminescence for the Na doped SnS thin film.