Structural, optical, and magnetic properties of low temperature hydrothermal synthesized (Gd, Al)-codoped ZnO nanoparticles

Abstract

Well-dispersed (Gd, Al)-codoped ZnO (Zn0.96–xGdxAl0.04O) nanoparticles (NPs) with different Gd content (x = 0–0.04) were synthesized by low temperature hydrothermal method and their structural, optical, and magnetic properties were investigated. All the as-prepared Zn0.96–xGdxAl0.04O NPs exhibit a hexagonal wurtzite structure with good crystal quality and small particle size (~3 nm). With increasing Gd-doping content from 0 to 0.04, the band gap Eg of Zn0.96–xGdxAl0.04O NPs increases from 3.46 to 3.62 eV owing to the substitution of Gd ions at Zn sites. The presence of additional intrinsic defects Zn-interstitial (Zni) and/or O-vacancy (VO) induced by Gd-doping results in the enhanced PL emission and increased PL lifetime. As compared with Al-doped ZnO, the room temperature ferromagnetic behavior of (Gd, Al)-codoped ZnO system is enhanced remarkably, which is explained based on the O-vacancy mediated exchange interactions between Gd and Al ions.