Defects passivity and UV emission characteristics in yttrium doped ZnO nanoparticles

Abstract

Trivalent rare-earth Yttrium ions, Ydoped ZnO nanoparticles (NPs) and undoped NPs with chemical formulae Zn1-xYxO (x = 0–7 mol%) are synthesized by sol–gel auto-combustion (SGAC) technique. X-ray diffraction (XRD) analysis shows the solid-solution behaviour of Yions into ZnO matrix up to 1 mol% doping level. Raman spectra of the solid solution sample reveals an enhancement in the characteristic E2 vibrational modes and a subsequent lowering of the defects mediated Raman modes at higher doping levels. The undoped NPs exhibit enhanced luminescence characteristics whereas doped NPs present optimum luminescence characteristics at 1 mol% doping level due to effectual substitution of Yions. The corresponding results exhibited by Yttria (Y2O3) accommodated 2 and 5 mol% Y doped ZnO NPs match surprisingly with those of 0.5 mol% Y doped single phase NPs. The luminescence characteristics are suggested to be influenced by the fluctuations of charge clouds of O2–ions by Y3+ions of Zn-O-Y and Y-O-Y bonds.