Synthesis of 1D and heavily doped Zn1−xCoxO six-prism nanorods: improvement of blue–green emission and room temperature ferromagnetism

Abstract

In this work, one-dimensional (1D) and heavily doped Zn_1−xCo_xO (x = 0.05, 0.1, 0.15 and 0.2) nanorods (NRs) were successfully fabricated by a new solvothermal method. Such a Zn_1−xCo_xO nanorod exhibits a hexagonal prism-like microcrystal with a pyramidal top. Analyses from transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) indicated that Zn_1−xCo_xO NRs possess perfect single crystal wurtzite structures. The influence of Co doping on the structural, optical and magnetic properties of NRs was investigated in detail. It was verified that Co was successfully doped into the ZnO wurtzite lattice structure by X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). The Zn_1−xCo_xO NRs show an obvious blue–green emission except for the weak UV emission. The corresponding luminescence mechanism was discussed, and the environment of cobalt in the ZnO wurtzite lattice was also identified through UV-vis spectroscopy. In addition, the magnetic hysteresis (M–H) curves demonstrated that the Zn_1−xCo_xO NRs possess obvious ferromagnetic characteristics at room temperature. These Zn_1−xCo_xO NRs are suggested to have potential applications in spintronic, field emission and optoelectronic devices, etc.