Structure of Ag-Containing Cu2ZnSnS4 Thin Films, Obtained by Spray Pyrolysis

Abstract

Kesterite Cu₂ZnSnS₄ thin films were synthesized by the spray pyrolysis method with subsequent annealing at temperatures in the range from 425 to 525°C. To understand the impact of Ag on the Cu₂ZnSnS₄ structural properties, changes in the elemental and phase composition, as well as microstructure were studied by electron microanalysis, X-ray phase and Raman analysis, scanning probe microscopy and scanning electron microscopy. The obtained samples have a compact morphology without appreciable voids and pores and crystallize in the tetragonal structure of kesterite CZTS. Phase analysis indicated incorporation of Ag in different concentrations without formation of other impurity compounds. An increase in the annealing temperature leads to an increase in the coherent scattering region, while the stoichiometric ratio of metals to chalcogen approaches 1, remaining close to that upon Ag alloying.