X-Ray Absorption Spectroscopy Study of Structure and Stability of Disordered (Cu src='/images/tex/996.gif' alt='_{bf 2}'> SnS src='/images/tex/20074.gif' alt='_{bf 3}'> ) src='/images/tex/21592.gif' alt='_{bf 1-x}'> (ZnS) src='/images/tex/21531.gif' alt='_{bf x}'> Alloys

摘要

Secondary phase segregation is hypothesized to have detrimental impacts on CuZnSnS (CZTS) thin-film solar cells. In this study, we demonstrate the potential of using kinetic stabilization to inhibit phase decomposition in CZTS. By growing CZTS films at low temperature, we achieve a kinetically stabilized alloy with an expanded solid solution window in the pseudoternary CuS–ZnS–SnS phase diagram. Using X-ray absorption spectroscopy, we study the structural evolution and stability of this metastable alloy upon annealing. For near-stoichiometric samples, we observe a continuous emergence of short-range order toward crystalline CZTS that is nearly complete after a 1-min anneal at 450 °C. For Zn-rich samples, we detect precipitation of ZnS upon annealing, which suggests that the excess Zn exists as cation antisite defects in metastable CZTS.