ZnO nanorods decorated with nanocrystalline (nc) Au Particles:Electronic structure and magnetic behaviours

Abstract

Electronic structures and magnetic behaviours of zinc oxide nanorods (ZnO-NRs) decorated with nanocrystalline “Au”-particles (nc-Au) have been studied using different spectroscopies, superconducting quantum interference device-type magnetometer and plane wave pseudopotential density functional theory calculations. The presence of intrinsic defects viz. zinc interstitials (Zni) and/or oxygen vacancies (VO) are established using different spectroscopies measurements. Ultraviolet photoelectron spectroscopy and valence band photoemission spectroscopy suggests that the valence band density of states of O 2p - Zn 4sp hybridized states of nc-Au/ZnO-NRs is higher than pure ZnO-NRs that could be correlated with its higher ferromagnetic behaviour. An enhanced room temperature ferromagnetism has been observed when nanocrystalline (nc) gold (Au) particles are decorated on the surface of ZnO-nanorods (ZnO-NRs). This enhanced magnetic moment in nc-Au/ZnO-NRs comes from the metallic electrons of nc-Au that induces large orbital magnetic moment at the nc-Au/ZnO-NR interface. Theoretical calculations shows the enhancement of the density of states at the valence band region of ZnO with a decoration of optimum content nc-Au particles along with the increase of oxygen vacancies in nc-Au/ZnO-NRs; that further confirms the enhancement of magnetization.