The morphology and optical properties of ZnO crystals fabricated by hydrothermal method under pulsed magnetic field

Abstract

In this study, ZnO crystals have been synthesized via hydrothermal method by adjusting the component of the precursor with the pulsed magnetic field. The effects of the molar ratio of the reactants and pulsed magnetic field applied in the synthesis process on the microstructure and optical properties of ZnO crystals were investigated systematically. The samples were characterized by X‐ray diffraction, scanning electron microscopy, UV‐Vis spectrophotometer and micro‐Raman scattering. The results demonstrate that pulsed magnetic field increases the defects concentration and reduces the band gap of ZnO. And it also promotes nucleation and crystal growth, the crystals obtained under pulsed magnetic field are more uniform and complete. The change of molar ratios influences the pH value so that the environment for the growth of ZnO crystals changed dramatically. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Effects of Ge substitution on the structural and physical properties of CuFeO2delafossite oxide

“…This absorption peak was primarily attributed to the charge-transfer excitation from the valence band to the conduction band. 26) The corresponding direct optical band gaps (E g ) of the delafossite samples were deduced from the relationship between the absorption coefficient and the photon energy (hν), which can be expressed as (αhν) 2 = A(hν − E g ), 27) where A is a constant. The optical band gaps were obtained from a plot of (αhν) 2 versus hν with the linear extrapolation of the curve to zero absorption, as shown in Fig.…”