The role of pre-annealing in the sulfurization of Cu-Zn-Sn stacked metal layer prepared by magnetron sputtering

Cu2ZnSnS4 (CZTS) films were fabricated by sulfurizing the stacked metal layer (SML) prepared by DC magnetron sputtering. The influence of pre-annealing treatment of the SML precursor on the sulfurization process and the crystal growth characteristics of the CZTS film were investigated. It was found that the crystallinity of the CZTS film was improved with the increase of the pre-annealing temperature and duration, indicating that the pre-annealing treatment promoted the sulfurization. The formation and distribution of the metal compounds in the SML dominated the sulfurization reaction. And, the microstructure and elemental composition of the CZTS film depended very much on the properties of the SML. The role of pre-annealing treatment in the sulfurization of metal stacked precursors is proposed. A highly crystalline p-type kesterite Cu2ZnSnS4 film with carrier concentration of 2.38 × 1017 cm−3, mobility of 1.38 cm2/V s and optical bandgap of 1.46 eV was obtained. The CZTS layers are expected to fabricate high efficiency thin film solar cells.