A comparative study of the defect point physics and luminescence of the kesterites Cu2ZnSnS4 and Cu2ZnSnSe4 and chalcopyrite Cu(In,Ga)Se2

In this contribution, we present a comparative study of the luminescence of the kesterites Cu₂ZnSnS₄ (CZTS) and Cu₂ZnSnSe₄ (CZTSe) and their related chalcopyrite Cu(In,Ga)Se₂ (CIGSe). Luminescence spectroscopy suggests that the electronic properties of Zn-rich, Cu-poor kesterites (both CZTS and CZTSe) and Cu-poor CIGSe are dictated by fluctuations of the electrostatic and chemical potentials. The large redshift in the luminescence of grain boundaries in CIGSe, associated with the formation of a neutral barrier is clearly observed in CZTSe, and, to some extent, in CZTS. Kesterites can therefore replicate the fundamental electronic properties of CIGSe.