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  Valakh, M.Ya.; Dzhagan, V.M.; Babichuk, I. S.; Fontane, X.; Perez-Rodriguez, A.; Schorr, S.: Optically Induced Structural Transformation in Disordered Kesterite Cu₂ZnSnS₄. JETP Letters 98 (2013), p. 255-258

10.1134/S0021364013180136

Abstract:
The kesteritestructured semiconductor Cu2ZnSnS4is one of the most promising compound for earthabundant lowcost solar cells. One of the complex problem on this way deals with its stoichiometry. In this work Raman spectra of Curich Cu2ZnSnS4 crystals are discussed in connection with the nonstoichiometric composition and disordering within the cation sublattice of the kesterite. The shift of the main A peak from 338 to 331 cm–1 and its broadening are attributed here to transition from the kesterite (I-4symmetry) to the disordered kesterite structure (I-2m symmetry). It is shown that this transition may also be driven by an intense light, which could stimulate transformation of Cu+ ion to Cu2+ ions and facilitates generation of CuZn defects on 2d crystalographic positions.