Defects and Its Effects on Properties of Cu-Deficient Cu_2ZnSnSe_4 Bulks with Different Zn/Sn Ratios

摘要

The concept of defect chemistry is applied to investigate the defects in Cu-deficient Cu_2ZnSnSe_4 (CZTSe) bulks liquid-phase sintered at 600 ℃ with soluble sintering aids of Sb_2S_3 and Te. By changing the Zn/Sn ratio, CZTSe changed from n-type to p-type semiconductor. Measurements of electrical properties with the changes in the Zn/Sn ratio were carried out to determine defect behaviors. Current jump in current-voltage tests and the big change in mobility can be attributed to the existence of Cu~(2+) defects, which became dominant at a higher Zn/Sn ratio of 1.35 and introduced stronger plasmon interaction.