Structural, optical and photoluminescence studies of heavily Mn-doped ZnO nanoparticles annealed under Ar atmosphere

Abstract

Undoped and heavily Mn-doped with ZnO nanoparticles (Zn 1-x Mn x O, x = 0.0, 0.05, 0.1 and 0.2) annealed under Ar atmosphere have been synthesized by a sol-gel method. The structural properties and optical absorption of the prepared samples have been examined by powder X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared (FTIR) spectroscopy and UV-visible spectrophotometer. Hexagonal wurtzite structure of the samples is confirmed by the XRD spectra. The average crystalline size of the Zn 1-x Mn x O nanoparticles has been calculated from X-ray line broadening and is decreased from 35.73 to 18.24 nm with increase in Mn concentrations from 0.0 to 0.2. The increase in lattice parameters indicates the substitution of Mn in ZnO lattice. SEM and TEM photographs indicated that the grain size of undoped ZnO is bigger than the Mn-doped ZnO which is due to the limitations of grain growth upon Mn doping. The presence of functional groups and the chemical bonding due to Mn doping is confirmed by FTIR spectra. PL spectra of the Zn 1-x Mn x O system showed that the shift in near band edge emission at 390 nm and a blue band emission at 450-490 nm which confirms the substitution of Mn.

Enhanced room temperature ferromagnetism and photoluminescence behavior of Cu-doped ZnO co-doped with Mn

“…The non-radiative Auger recombination processes associated with degenerated electrons, in which the energy released by an electron recombination is immediately absorbed by another electron and then this energy is dissipated by phonons. The increase of defects density states leads to increase the non-radiative recombination centers and thus resulting in reduction of emission intensity [28]. Deepa et al also noticed similar reduction of emission intensity in Mn doped ZnO thin films with the increase of Mn doping concentration [29].…”

Formulation of Synthesized Zinc Oxide Nanopowder into Hybrid Beads for Dye Separation

“…Where the two FTIR spectrums of ZnO nanoparticles and their polymeric hybrid showed identical characteristic peaks at about 551 cm −1 in case of pure ZnO which corresponds to the Zn-O bond stretching vibration that shifted to about 505 cm −1 for the polymeric hybrid [33]. Moreover the medium to weak bands at 889 cm −1 for pure ZnO and 852 cm −1 at ZnO polymeric hybrid are assigned to the vibrational frequencies due to the change in the microstructural features into Zn-O lattice [34]. The weak peaks sited at 1165 cm −1 and 1383 cm −1 for pure ZnO that shifted to 1064 cm −1 and 1392 cm −1 for polymeric hybrid were regarding presence of C-O and C-H vibration modes of PVP, which acts as a capping agent for synthesis of nano-zinc oxide [35].…”

Microstructure, surface morphology and optical properties of Na x Cu y Zn1−x−y O thin films

“…It can be explained that such behavior is due to non-radiative Auger recombination transition associated with degenerated electrons, in which the energy released by an electron recombination is immediately absorbed by another electron, and then this energy is dissipated by phonons. Auger process has been thought of as a major reason of non-radiative recombination in semiconductor [45]. In wide band gap semiconductor, Auger process depends on the concentration of doping atom and defects in the lattice.…”