Deep electron traps and origin ofp-type conductivity in the earth-abundant solar-cell material Cu2ZnSnS4

• DOI: 10.1103/physrevb.87.155206
• Publication Date: 2013-04-15T21:20:13Z
• Authors: Dong Han; Y. Y. Sun; Junhyeok Bang; Y. Y. Zhang; Hong-Bo Sun; Xian-Bin Li; S. B. Zhang
• Keywords: Acceptor

Using hybrid functional calculation, we identify the key intrinsic defects in Cu${}_{2}$ZnSnS${}_{4}$ (CZTS), an important earth-abundant solar-cell material. The Sn-on-Zn antisite and defect complex having three Cu atoms occupying a Sn vacancy are found to be main deep electron traps. This result explains optimal growth condition for CZTS, which is poor Zn rich, as several recent experiments. We show that, under that minimizes traps, could contribute majority of hole carriers, while Cu-on-Zn will become dominant acceptor if favors its formation.