Fig. 4. (a) XRD patterns of pure ZnO nanoparticles at 750 °C, Zn1-xMgxO nanoparticles,partially opened nanowire-on-spherical shells, hemispheric shells and chainlike nanoparticles with x = 2.87%, 3.51%, 4.43% and 5.01% at 750, 850, 900 and1000 °C, respectively. (b) XRD patterns of around the (002) peaks.