Transmittance spectra of Cu2ZnSnS4 thin films

Thin films of the quaternary compound semiconductor Cu2ZnSnS4 (CZTS) were produced by ion beam sputtering at substrate temperatures of 323 K, 423 K, and 573 K. The chemical and structural properties of the thin films were studied by electron microprobe analysis and grazing incidence x-ray diffraction. It was shown that, similarly to the corresponding crystals, the main phase in the thin films was Cu2ZnSnS4 with a tetragonal lattice and the space group l4Їl4Ї . The transmittance spectra near the fundamental absorption edge were used to establish the energies and nature of optical transitions. The energies of crystal-field splitting (Δcr) and spin–orbit splitting (Δso) of the valence band of the Cu2ZnSnS4 quaternary compound were calculated on the basis of the Hopfield quasi-cubic model