Structural refinement, photoluminescence and Raman spectroscopy of Wurtzite Mn-doped ZnO pellets

Abstract

We report the results of the Rietveld refinement, photoluminescence and Raman spectroscopy of Mn-doped ZnO ceramic pellets. Rietveld refinement shows that samples crystallize in the wurtzite structure and for the Mn-doped sample indicates that the Mn atoms substitute the Zn tetrahedral crystallographic sites in the ZnO host lattice. The emission and absorption spectra of Mn-doped ZnO have been investigated in the Visible-UV region and the data have been interpreted in terms of the wurtzite ZnO electronic structure. Two broad bands, one due to superposition between donor bound excitons (DX) and free excitons (FX) and other due free-to-bond excitonic recombination (FB) dominates the low-temperature photoluminescence spectra of Mn-doped ZnO bulk. In the Raman spectrum, an extra mode at $\sim$520 cm$^{-1}$ has been observed in agreement with earlier works, and it is an indicator for the incorporation of Mn$^{+2}$ ions into the ZnO host matrix since it is not is observed in ZnO pristine.