Structural and optical properties of sol-gel synthesised Zn(1-x)Mg(x)O nanocrystals.

Zn(1-x)Mg(x)O nanocrystals with various compositions (x = 0-0.1) were synthesised by sol-gel process using tri ethanol amine (TEA) as a capping agent. The structural properties of the prepared materials were studied by X-ray diffraction analysis. Un-agglomerated nanocrystals with spherical morphology were observed by scanning electron microscope (SEM). The presence of Mg in the Zn(1-x)Mg(x)O was confirmed by X-ray photoelectron spectroscopy (XPS). Moreover, the Mg composition relatively increases in the synthesised nanocrystals as it increases in the precursor solution. The optical absorption studies of the Zn(1-x)Mg(x)O samples show the blue shift from the pure ZnO due to the incorporation of Mg in ZnO lattice. The photoluminescence studies demonstrated that the intensity of defect related deep level emission increases drastically with increasing the x value from 0.02 to 0.08 and decreases sharply on further increase of Mg from 0.08 to 0.1. The mechanism for the enhanced green emission was explained based on the structural properties of the Zn(1-x)Mg(x)O samples.