Red Luminescence in Sonochemically Synthesized Nitrogen Doped ZnO Nanorods

Sonochemically prepared nanopowders of ZnO pure and doped with 'N' ion are reported in this investigation. These powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FTIR), photoluminescence (PL) and UV-visible (UV-VIS) absorption measurements. The average crystallite sizes of nitrogen doped ZnO nano-crystallites were found to be 59 nm and 48 nm (+/- 1.0 nm) for continuous (CS) mode and pulsed (PS) mode sonicated powders respectively. Presence of nitrogen was confirmed from energy dispersive analysis of X-rays (EDAX) and infrared spectral measurements. Excitation with 354 nm band of light gave red emission bands at 608 nm and 627 nm in both CS and PS mode ZnO:N powders. Although five absorption bands were observed for ZnO and ZnO:N powders, these absorption bands changed their position upon 'N' incorporation into ZnO lattice. The blue shift of these bands has been explained in the light of quantum confinement effect due to size reduction in this system.