Role Of Zn-interstitial Defects In The Ultraviolet Emission From ZnO

ZnO layers having variable percentage of Zn-contents were prepared to ascertain the role of Zn-interstitial defect in the ultraviolet (UV) emission from ZnO with the help of photoluminescence (PL) measurements. The typical PL spectrum performed at room temperature displayed a dominant UV line at 3.28 eV and a visible line centered at 2.25 eV. A detailed investigation reveals that the UV emission is due to bound exciton transition-Zn-interstitial transition. The UV intensity due to Zn-rich sample was almost double as compared to that of the sample with lower Zn-contents. The results obtained from the energy dispersive x-ray spectrum (EDAX) and Raman spectroscopy strengthened the PL results