Effect of Plasma Treatment on Native Defects and Photocatalytic Activities of Zinc Oxide Tetrapods

ZnO tetrapods, as a ZnO nanostructure with a low defect concentration, were subjected to plasma treatments using different gases to induce different types of defects in the samples and examine their effects on sample properties. Hydrogen and argon plasmas resulted in significant oxygen deficiencies, but no defect emission appeared. Oxygen plasma had only a minor effect on the sample composition, but it resulted in the appearance of defect emission and a significant overall reduction in luminescence intensity. On the other hand, the photocatalytic activity was significantly reduced in samples exhibiting oxygen deficiencies. It can thus be concluded that oxygen vacancies do not participate in the green emission of ZnO and also that their presence at the sample surface does not enhance the photocatalytic activity.