Vibrational properties of stannite and kesterite type compounds: Raman scattering analysis of Cu2(Fe,Zn)SnS4

This work reports the analysis of the vibrational properties of stannite–kesterite Cu2(Fe,Zn)SnS4 compounds that has been performed by Raman scattering measurements. The detailed analysis of the experimental spectra has allowed determining the frequency and symmetry assignment of the main and weaker peaks from both stannite Cu2FeSnS4 (CFTS) and kesterite Cu2ZnSnS4 (CZTS) phases. The measurements performed in the kesterite CZTS samples have also revealed the presence of local inhomogeneities that are characterised by an additional peak in the spectra at about 331 cm−1. This peak has been related to the presence in these local regions of a high degree of disorder in the cation sublattice, in agreement with previous neutron diffraction analysis in similar samples. Finally, the spectra from the solid solution alloys show a one-mode behaviour of the main A/A1 peak with the chemical composition.

► Analysis of main and weaker Raman peaks from Cu2FeZnS4 and Cu2ZnSnS4 compounds.
► Identification of a cation disorder induced Raman peak in Cu2ZnSnS4.
► Analysis of spectral features of main Raman peaks from Cu2(Fe,Zn)SnS4.