Optical and structural properties of Mn-doped ZnO nanorods grown by aqueous chemical growth for spintronic applications

• Synthesis of Mn-doped ZnO nanorods by hydrothermal method is demonstrated.
• Doping with Mn significantly changes the morphology of ZnO nanorods.
• Additional Mn-induced Raman modes evidence incorporation of Mn into ZnO matrix.
• Formation of secondary ZnMn2O4 spinel phase is found at high Mn concentrations.
• Contrast MFM images of ZnO:Mn nanorods indicate ferromagnetism at room temperature.

The effect of Mn-doping on the structural, morphological, optical and magnetic properties of the ZnO:Mn nanorods (NRs) synthesized by aqueous chemical process is reported. Grown ZnO:Mn NRs are shown to have hexagonal end facets and the diameters increasing with nominal Mn content. Optical absorption measurements show a decrease in optical band gap with increase of Mn concentration. Raman spectroscopy revealed significant modification of the lattice vibrational properties of the ZnO matrix upon Mn doping. The additional Mn-related vibrational mode, intensity of which increases with amount of Mn can be regarded as an evidence of Mn incorporation into the host lattice of the ZnO. At high Mn concentrations, coexistence of hexagonal Zn1 − xMnxO phase along with the secondary phases of ZnMn2O4 cubic spinel is revealed. Magnetic properties of ZnO:Mn NRs are studied by combinatorial atomic force microscopy and magnetic force microscopy imaging, and obtained clear magnetic contrast at room temperature provides a strong evidence of ferromagnetic behavior.