Quantum dots growing of Mn/ZnO nanowires and optimizing the optical properties

Mn-doped zinc oxide (ZnO) nanostructures with different manganese concentrations along with high structural and optical quality were grown through a simple method without using any metal catalysts and through the source quantum dots of the nanowires (ZnO and MnO2). The cross section of the prepared nanowires has been a hexagon with a diameter between 35 and 50 nm and a length between 3 and 6 μm. The surface morphology of the samples was characterized by scanning electron microscopy. The results of the x-ray diffraction analysis showed the wurtzite structure for the prepared samples with a strong preferred peak (002). The energy dispersive x-ray spectra showed a high percentage of Mn at the tip of the samples, and the x-ray photoelectron spectroscopy showed the spectra of MnO2 in the structure of the nanowires. These wires produced a large PL emission peak in the ultraviolet (UV) region and a relatively high peak in the visible region. With the increase of the doping percentage, the intensity of the visible emission increased, and this amount reached to the highest peak intensity and maximum quantum yield (QY=39%) at 5% of the dopant as the quenching point. The UV peak of the Mn/ZnO nanowires amounts to 11-nm blueshifted with respect to pure ZnO nanowires confirmed by the UV–visible absorption spectra.