Structural, optical and magnetic properties of stencil-free printed ZnO layers doped with Fe2+ and Fe3+ ions

Abstract

In this paper we investigate the doping effect of FeO and Fe2 O3 on the structural, optical and magnetic properties of ZnO layers prepared by a new stencil-free technique. Samples were characterized by X-ray diffraction (XRD), atom force and magnetic force microscopy, photoluminescence and Raman spectroscopy. A quite high quality of the printed Fe-doped ZnO layers was demonstrated. It was shown that the incorporated Fe2+ or Fe3+ ions substitute Zn2+ ions in ZnO lattice and, unlike the doped layers prepared by other technological methods, were uniformly distributed in the Zn2+ sites. The levels of doping with different impurities that make it possible to obtain layers free of second phase inclusions were established. The printed ZnO:Fe layers illustrated pronounced ferromagnetic behavior at ambient conditions. The values of the magnetic field correlated with the impurity content. The value of magnetization of the ZnO:Fe3+ layers was shown to be approximately twice that of the printed ZnO:Fe2+ layers. At the same time, magnetization of ZnO:Fe2+ layers was approximately the same as of the printed ZnO:Co2+ and ZnO:Mn2+ layers studied by us previously. The higher magnetization observed in ZnO:Fe3+ layers was supposed to be due to the carrier-mediated mechanism of magnetization in these layers.