Ferromagnetism in High-Surface-Area ZnO Nanosheets Prepared by a Template-Assisted Hydrothermal Method

High-surface-area ZnO nanosheets are prepared using a template-assisted hydrothermal method. A saturation moment as high as 0.02 emu/g is obtained for the ZnO nanosheets. Both photoluminescence spectroscopy and x-ray photoelectron spectroscopy demonstrate the existence of abundant oxygen vacancies on the surfaces of the nanosheets. In addition, the oxygen vacancy concentration increases with an increasing nanosheet surface area. The results show that the origin of the room-temperature ferromagnetism is closely related with a large surface area and oxygen vacancies of the nanosheets. This finding suggests that the high-surface-area ZnO nanosheets are promising to be applied to spintronic devices.