Thermal studies of Mn²⁺-doped ZnO powders formation by sol–gel method

In the present contribution, the study of nanostuctured powders of Mn²⁺-doped ZnO with different doping concentration (1, 2, 5 at%) was approached. The samples were synthesized by sol–gel method, and the influence of the Mn content on the thermal behavior of the resulted gels was established by thermogravimetric and thermodifferential analysis. Based on the results obtained by thermal analysis, the gels were isothermally treated at 500 °C, 1 h. The XRD powder measurements revealed that all samples had hexagonal wurtzite structure and no other secondary phases were observed suggesting that the Mn²⁺ ions have substituted Zn sites. Moreover, the incorporation of Mn²⁺ into ZnO lattice was also confirmed by Infrared and Raman spectroscopy. Energy-dispersive X-ray analysis indicates the existence of Mn²⁺ in all samples, even in that with 1 at% Mn. The morphology of the samples depends on Mn²⁺ concentrations. A decrease in the grain size with the increase in Mn²⁺ concentration was observed. Mn²⁺-doped ZnO nanopowders with desired structure and properties as promising materials in potential piezoelectric applications, were obtained.