Enhanced photoluminescence of nitrogen-doped ZnO nanoparticles fabricated by Nd : YAG laser ablation

Undoped and nitrogen-doped ZnO (ZnO : N) with a typical size of about 60 nm were fabricated by Nd : YAG laser ablation of a Zn target under mixed O2/N2 gas. Their photoluminescence (PL) was studied. Compared with undoped ZnO, approximately a 500% PL enhancement was observed when nitrogen gas at 150 kPa was added to a fixed 100 kPa background oxygen atmosphere. The PL evolution of ZnO : N nanoparticles with temperature increasing from 20 to 290 K indicates that the dominant emission at room temperature is mainly composed of near band-edge(NBE) emissions. Furthermore, it is possible that NO-Zni complexes, formed by nitrogen substitution of oxygen (NO) and interstitial zinc (Zni), are responsible for the observed PL enhancement, which was centred at the ~3.26 eV NBE emission.