Li-dan Tang

Structural, optical and electrical properties of Li-doped ZnO thin films influenced by annealing temperature

Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500–600 °C and the p type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.

Effects of pulsed electromagnetic field on morphology and size of cobalt oxalate particles

Abstract It is of much significance to control the morphology and size of cobalt oxalate precursor for the preparation of cobalt powders. The cobalt oxalate powders were prepared by conventional precipitation at different initial cobalt chloride concentrations in the presence of pulsed electromagnetic field. Scanning electron microscopy images and size analysis indicate that spherical and fine cobalt oxalate particles with uniform size are obtained. Conductivity analysis demonstrates that pulsed electromagnetic field plays an important role in the preparation of monodisperse cobalt oxalate particles owing to the inhibition of the secondary nucleation. X-ray powder diffraction results show the formation of β-CoC2O4·2H2O with a micro-size change of cobalt oxalate grain when the extra pulsed electromagnetic field is present. Fourier transform infrared spectroscopy results indicate that the transition of bond way in CoC2O4·2H2O favours to develop stable crystal nucleus. Besides, a possible mechanism for the interaction between pulsed electromagnetic field and cobalt oxalate reaction system was preliminarily discussed.

Al doping effects on ZnO nanostructure and growth mechanism

Abstract High-energy and large surface Al-doped ZnO nanostructure arrays were fabricated using hydrothermal methods under the action of pulsed electromagnetic field. The morphology, structure and component features were analysed by field emission scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. Results showed that the hexagonal sheet like Al-doped ZnO regularly interlaced with each other and vertically grew on the FTO substrate. The surfaces of the ZnO nanosheets were larger than those of the undoped ZnO nanorods. In addition, the formation mechanism of Al-doped ZnO nanostructure was explained.