Doping Zn2+ in CuS Nanoflowers into Chemically Homogeneous Zn0.49Cu0.50S1.01 Superlattice Crystal Structure as High-Efficiency n‑Type Photoelectric Semiconductors

Doping Zn2+ in CuS nanoflower into chemically homogeneous superlattice crystal structure is proposed to convert p-type CuS semiconductor to an n-type CuS semiconductor for significantly enhanced photoelectric response performance. In this study, the chemically homogeneous Zn-doped CuS nanoflowers (Zn0.06Cu0.94S, Zn0.26Cu0.73S1.01, Zn0.36Cu0.62S1.02, Zn0.49Cu0.50S1.01, Zn0.58Cu0.40S1.02) are synthesized by reacting appropriate amounts of CuCl and Zn­(Ac)2·2H2O with sulfur powders in ethanol solvothermal process. By tuning the Zn/Cu atomic ratios to ∼1:1, the chemically homogeneous Zn-doped CuS nanoflowers could be converted to the perfect Zn0.49Cu0.50S1.01 superlattice structure, corresponding to the periodic Cu–S–Zn atom arrangements in the entire crystal lattice, which can induce an effective built-in electric field with n-type semiconductor characteristics to significantly improve the photoelectric response performance, such as the lifetime of photogenerated charge carriers up to 6 × 10–8–6 × 10–4 s with the transient photovoltage (TPV) response intensity to ∼44 mV. This study reveals that the Zn2+ doping in CuS nanoflowers is a key factor in determining the superlattice structure, semiconductor type, and the dynamic behaviors of charge carriers.