Induced ferromagnetic and gas sensing properties in ZnO-nanostructures by altering defect concentration of oxygen and zinc vacancies

Abstract

We report on the effect of the synthesis reaction-time on the structural, optical, magnetic and sensing properties of ZnO-nanostructures. Electron paramagnetic resonance and photoluminescence analyses reveal that singly ionized oxygen vacancies (VþO ) and zinc vacancies(VZn) are the main defects and that their relative concentration decreases within creasing particlesizes, resulting in decreased ferromagnet- ism (FM). Moreover, the sensing performance decreased with an increase in nanostructures synthesis reaction-time due to a decreased surface area, as well as VþO and VZn concentrations. Thus, the synthesis reaction-time clearly controls the relative occupancy of the VþO and VZn present on the surface of ZnO- nanostructures, which is enunciated to be critical for enhanced FM and sensing characteristics.