Defect-related optical properties of Mg-doped ZnO nanoparticles synthesized via low temperature hydrothermal method

Abstract

In this work, the monodispersed Mg-doped ZnO (Zn1-xMgxO, x = 0–0.06) nanoparticles (NPs) were synthesized through low temperature hydrothermal method. The as-prepared Zn1-xMgxO NPs exhibited single hexagonal wurtzite structure, confirming the incorporation of Mg2+ into ZnO lattice by replacing the Zn2+ ions. Optical analyses suggested the optical band gap of Zn1-xMgxO NPs increased from 3.46 to 3.59 eV with increasing Mg content from 0 to 0.06. The photoluminescence (PL) spectra of undoped and Mg doped ZnO NPs showed strong and broad visible emissions. With increasing Mg2+ content, the PL peak energy, intensity, and PL lifetime increased. The broad visible emission band was consisted of green, yellow, and red emission bands associated with different defect states. Based on the Mg content- and the temperature-dependent PL spectra, we proposed the possible origin of the observed visible emissions, which can be favorable for further understanding the correlation between the lattice states and PL property of doped ZnO NPs.