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  Bär, M.; Schubert, B.-A.; Marsen, B.; Schorr, S.; Wilks, R.G.; Weinhardt, L.; Pookpanratana, S.; Blum, M.; Krause, S.; Zhang, Y.; Yang, W.; Unold, T.; Heske, C.; Schock, H.-W.: Electronic structure of Cu₂ZnSnS₄ probed by soft x-ray emission and absorption spectroscopy. Physical Review B 84 (2011), p. 035308/1-6

10.1103/PhysRevB.84.035308

Abstract:
The electronic structure of Cu2ZnSnS4 has been investigated by S L2,3 x-ray emission and absorption spectroscopy. An empirical assignment of the most prominent spectral features of the valence and conduction band, respectively, can be made based on a comparison with spectra of corresponding binary compounds and with calculated densities of states. We find that the top of the valence band is dominated by hybridized antibonding Cu 3d – S 3p (Sn 5s – S 3p) states, while the bottom of the conduction band is dominated by respective Sn 5s – S 3p states. We also determine the electronic band gap near the Cu2ZnSnS4 surface to be 1.5 (± 0.3) eV.