Induced effects by the substitution of Zn in Cu2ZnSnX4 (X= S and Se)

Publication date: Available online 10 February 2016
Source:Thin Solid Films
Author(s): Guohua Zhong, Kinfai Tse, Yiou Zhang, Xiaoguang Li, Li Huang, Chunlei Yang, Junyi Zhu, Zhi Zeng, Zhenyu Zhang, Xudong Xiao
Based on the density functional theory with hybrid functional approach, we have studied the structural and thermodynamic stabilities of Cu 2 MSnX 4 (M = Zn, Mg, and Ca; X = S and Se) alloy, and have further investigated the electronic and optical properties of stable Cu 2MgSnS 4 and Cu 2MgSnSe 4 phases. Thermal stability analysis indicates that Cu 2MgSnS 4 and Cu 2MgSnSe 4 are thermodynamically stable, while Cu 2CaSnS 4 and Cu 2CaSnSe 4 are unstable. The ground state configuration of the compound changes from kesterite into stannite structure when Zn atoms are substitued by larger Mg or Ca atoms. An energy separation between stannite and kesterite phase similar to that of CZTS is observed. Calculated electronic structures and optical properties suggest that Cu 2MgSnS 4 and Cu 2MgSnSe 4 can be efficient photovoltaic materials.