H.L. Liu

A study of structural, optical and magnetic properties of Cr, Ce co-doping in ZnO diluted magnetic semiconductors

We present the structural, optical and magnetic properties of pure ZnO, Zn0.97Cr0.03O and Zn0.96Cr0.03Ce0.01O samples, the samples were synthesized by sol–gel method. The microstructures, optical and magnetic properties of samples were investigated by X-ray diffraction (XRD), transmission electron microscope , X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), Raman spectroscopy and vibrating sample magnetometer. XRD and XPS data confirmed the formation of a single phase wurtzite type ZnO structure for all the samples. PL measurements revealed that all the three samples had an UV emission and a defect emission, and the Ce ions doping induced a red shift in the UV emission and an increase in the defect emission. Zn0.97Cr0.03O and Zn0.96Cr0.03Ce0.01O samples showed the obvious hysteresis loops at room temperature and the saturation magnetization (Ms) increases with incorporating of Ce.

Effects of different sintering atmosphere on the structure and properties of Cu-doped ZnO powders prepared by sol–gel method

Cu-doped ZnO powders have been successfully synthesized by the sol–gel method in different sintering atmospheres, including argon and air, respectively. The effects of the sintering atmosphere on the structure, magnetic and optical properties of Cu-doped ZnO were investigated in detail by X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, vibrating sample magnetometer and photoluminescence measurements. The results showed that the Cu-doped ZnO powders sintered in Ar had a hexagonal wurtzite structure without any secondary phase, however, CuO was observed in the sample sintered in air. From the magnetic and photoluminescence spectra, it could be seen that the sintering atmospheres strongly influenced the magnetic and optical properties of the powders.

Low-temperature growth and optical properties of Ce-doped ZnO nanorods

Ce-doped ZnO nanorod arrays were grown on zinc foils by a hydrothermal method at 180°C. The effects of Ce-doping on the structure and optical properties of ZnO nanorods were investigated in detail. The characterisation of the rod array with X-ray diffraction and X-ray photoelectron spectroscopy indicated that Ce3+ ions were incorporated into the ZnO lattices. There were no diffraction peaks of Ce or cerium oxide in the pattern. From UV-Vis spectra, we observed a red shift in the wavelength of absorption and decreased band gap due to the Ce ion incorporation in ZnO. The photoluminescence integrated intensity ratio of the UV emission to the deep-level green emission (I UV/I DLE) was 1.25 and 2.87, for ZnO and Ce-doped ZnO nanorods, respectively, which shows a great promise for the Ce-doped ZnO nanorods with applications in optoelectronic devices.Ce-doped ZnO nanorod arrays were grown on zinc foils by a hydrothermal method at 180°C. The effects of Ce-doping on the structure and optical properties of ZnO nanorods were investigated in detail. The characterisation of the rod array with X-ray diffraction and X-ray photoelectron spectroscopy indicated that Ce3+ ions were incorporated into the ZnO lattices. There were no diffraction peaks of Ce or cerium oxide in the pattern. From UV-Vis spectra, we observed a red shift in the wavelength of absorption and decreased band gap due to the Ce ion incorporation in ZnO. The photoluminescence integrated intensity ratio of the UV emission to the deep-level green emission (I UV/I DLE) was 1.25 and 2.87, for ZnO and Ce-doped ZnO nanorods, respectively, which shows a great promise for the Ce-doped ZnO nanorods with applications in optoelectronic devices.