Optical Properties of Mg-Substituted ZnO Nanoparticles Obtained by Solution Growth

In this paper, we report the optical properties of magnesium (Mg)-substituted zinc oxide (ZnO) (Zn_1-xMgxO) nanoparticles (diameter ≤ 20 nm). The ZnO and alloyed nanoparticles were synthesized by chemical route and have Wurzite structure. The maximum Mg substitution reported here is ≈7.5%. This leads to a blue shift of the absorption spectra by 0.5 eV as well as a blue shift of the near-band edge photo luminescence. Our analysis shows that small change in average size of the nanoparticles, as described in this paper, does not have much effect on the observed blue shift of the absorption spectra due to alloying. At the maximum concentration of Mg incorporated into ZnO, the material does not show phase segregation and retains the excitonic nature of the fundamental-absorption edge.