Effect of Mg doping on structural, morphological, optical and thermal properties of ZnO nanoparticles

Doping of group II elements in ZnO is an efficient way to enhance the optical properties of ZnO nanoparticles. For this purpose, Zn1-xMgxO nanoparticles (x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1) are synthesized using co-precipitation technique. Effect of 'Mg' doping on structural, morphological, optical and thermal properties of ZnO nanoparticles is investigated. XRD results verify that synthesized nanoparticles are poly-crystalline with typical hexagonal wurtzite structure and possess no other impurity or dopant phases. Crystallite size is increased with the increase in 'Mg' content. SEM analysis reveals that polyhedral grains are aggregated with the increase in doping concentration of Mg. For the highest dopant concentration, surface morphology is entirely changed with the formation of nanowires. Optical band gap energy of Mg-doped ZnO nanoparticles is greater than that of pristine ZnO nanoparticles. The blue shift in band gap is observed with Mg content x <= 0.04, followed by red shift for higher Mg content. The decrease in phase transition and increase in decomposition temperature for Mg-doped ZnO nanoparticles suggest their thermal stability. Tailoring of band gap makes ZnO nanoparticles a promising material for photocatalysis, optoelectronic and display devices.