Fabrication of Co-doped ZnO nanorods for spintronic devices

Abstract

Herein, single-crystalline Zn1−xCoxO (0.0≤x≤0.10) nanorods were prepared using a facile microwave irradiation method. Structural analyses by X-ray diffraction and transmission electron microscopy revealed the incorporation of Co2+ in the lattice position of Zn2+ ions into the ZnO matrix. Field emission scanning electron microscopy and TEM micrographs revealed that the length and diameter of the undoped ZnO nanorods were about ∼2 μm and ∼200 nm, respectively. For Co-doped ZnO, the length and diameter were found to increase with an increase of Co doping. The selected area electron diffraction pattern indicated that the Zn1−xCoxO (0.0≤x≤0.10) nanorods had a single phase nature with the preferential growth direction along the [0 0 1] plane. Raman scattering spectra confirmed the shift of the E 2 high mode toward a lower wave number, suggested successful doping of Co ions at Zn site into the ZnO. Magnetic studies showed that Co doped ZnO nanorods exhibited room temperature ferromagnetism and the magnetization value increased with an increase in Co doping. The synthesis method presented here is a simple approach to prepare ZnO based diluted magnetic semiconductors nanostructures for practical application to spintronic devices.