Abstract: | Un-doped and Mn-doped ZnO nanoparticles were successfully synthesized in an ethanolic solution by using a sol-gel method.
Material properties of the samples dependence on preparation conditions and Mn concentrations were investigated while other
parameters were controlled to ensure reproducibility. It was observed that the structural properties, particle size, band
gap, photoluminescence intensity and wavelength of maximum intensity were influenced by the amount of Mn ions present in the
precursor. The XRD spectra for ZnO nanoparticles show the entire peaks corresponding to the various planes of wurtzite ZnO,
indicating a single phase. The diffraction peaks of doped samples are slightly shifted to lower angles with an increase in
the Mn ion concentration, signifying the expansion of the lattice constants and increase in the band gap of ZnO. All the samples
show the absorption in the visible region. The absorbance spectra show that the excitonic absorption peak shifts towards the
lower wavelength side with the Mn-doped ZnO nanoparticles. The PL spectra of undoped ZnO consist of UV emission at 388 nm
and broad visible emission at 560 nm with varying relative peak intensities. The doping of ZnO with Mn quenches significantly
the green emission while UV luminescence is slightly affected. |