Anionic polymerization in Co and Fe doped ZnO: Nanorods, magnetism and photoactivity

The growth mechanism of Zn1−xCoxO (ZC) and Zn1−xFexO (ZF) nanorods, and resulting magnetic and optical properties have been studied. The ZC and ZF nanorods were prepared by sol–gel synthesis route. X-ray diffraction results in polycrystalline phase with wurtzite structure of ZC and ZF nanorods. The transmission electron microscopy images show the formation of nanorods. The growth mechanism of nanorods is explained on the basis of agglomeration of Zn2+ with OH− ions which is react with poly vinyl alcohol involve anionic polymerization of oriented growth. Magnetic measurement of ZC and ZF nanorods exhibit superferromagnetic behavior and the large value of saturation magnetization observed at room temperature. The magnetization below room temperature measurement confirms the origin of observed magnetism. Raman and photoluminescence spectra show good photoactivity. The observed Raman active modes show wurtzite structure belongs to C6v symmetry group. Photoluminescence measurements of ZC and ZF nanorods exhibit ultraviolet peaks at 413.90 nm (∼3 eV) due to free exciton emission and at 546.31 nm (∼2.27 eV) due to transition from deep donor states which arises from oxygen vacancy.