Luminescence properties of ZnO and Eu 3+-doped ZnO nanorods

Abstract

We have studied crystal structure, shape, and photoluminescence (PL) properties of undoped and Eu-doped ZnO nanorods. The transmission electron microscope studies show that the undoped and Eu-doped ZnO nanocrystals have the rod-like shape. Under the high energy excitation above the band-gap energy of ZnO, broad PL band as well as bound-exciton emission were observed in Eu-doped ZnO nanorods. On the contrary, several sharp PL lines were observed when the excitation energy almost coincides with the intra-4f transition energy of Eu 3+ ions. The broad PL band is thought to be due to the defects in ZnO nanorods while the sharp PL peaks are attributed to intra-4f transitions of Eu 3+ ions in ZnO nanorods.