The Effects of Mn Doping on the Structural and Optical Properties of ZnO

Abstract

Zn1−xMnxO (x = 0.00, 0.01, and 0.05, respectively) was synthesized by using solid state reaction method. The structural properties were characterized by using X-ray diffraction and scanning electron microscopy. Optical properties were investigated by UV-visible spectroscopy. X-ray diffraction patterns indicate that all samples have hexagonal wurtzite structure without any impurity phases. The diffraction intensity increases and the peak position shifts to a lower 2θ angle with Mn concentration. The lattice parameters a and c, the volume of unit cell increase with Mn content indicating that Mn 2+ ions go to Zn 2+ ions in ZnO lattice. The grain size increases with Mn doping while the microstrain and dislocation density decrease. UV-vis spectra of the samples show that undoped ZnO sample has an energy band gap Eg of 3.34 eV. The optical study indicates a red shift in the absorbance spectra and a decrease in the band gap Eg with Mn content. This decrease of band gap may be attributed to the influence of dopant ions. The morphology and grain distribution of ZnO samples were analysed by scanning electron microscopy. The particle sizes are higher in doped samples when compared to the undoped sample and the surface roughness increases with Mn content. The grains are closely, densely packed and pores/voids between the grains increase with Mn content.

Solubility of Mn in ZnO Crystallites Synthesized Using Solid State Techniques

“…In all these cases there were no impurity of secondary peaks observed as the dopant falls below 30% compared this work. The single-phase hexagonal wurtzite structure of ZnO as was observed in the samples conforms to those of Senol et al [19], Sebayang et al [20] and Bilgili [18]. This is an indication that, the procedure and conditions used for this solid state method is unique since at a low temperature of 200 °C and a high doping concentration of above 20% (Mn < 30%), no additional or secondary phase was observed.…”

“…With the work of Sebayang et al (2020), the peak intensity of the Mn doped ZnO nanoparticles was lower than that of the undoped ZnO and also found to be shifted to higher angles at a maximum doping concentration of 9%. Bilgili [18] observed an increase in the intensity of the diffraction peaks and a shift towards lower angles as the doping concentration increases. In all these cases there were no impurity of secondary peaks observed as the dopant falls below 30% compared this work.…”

“…Bilgili [18] uses the solid state method to dope ZnO with 1% and 5% Mn. During the synthesis, the appropriate amount of ZnO and Mn2O3 powders were ground and calcined for 8 h at 450 °C.…”

A systematic study on luminescence characterization of lanthanide-doped BeO ceramic dosimeters

“…The XRD patterns showed that BeO ceramics doped with different Ln 3+ ions synthesized under the same synthesis processes (i.e., calcination and sintering conditions) had the same phase. The XRD patterns do not contain any peaks related to Ln 3+ ions, this may be attributed to the incorporation of Ln 3+ ions into Be 2+ lattice sites rather than interstitial ones [39].…”

“…Both lattice parameters (a and c) and cell volume (V) were decreased with Ln 3+ doping due to an increase in the existing defect concentration in the lattice. This may be attributed to the larger ionic radius of Ln 3+ compared to that of Be 2+ , hence leading to a lattice contraction [39,40]. Furthermore, The Be-O bond length values obtained from the XRD data of the BeO:Ln 3+ samples are slightly lower than that of the undoped BeO sample (see Table 1.…”