Fe ions were implanted into well-aligned single-crystal ZnO nanotips grown on SiO 2/quartz substrates using metal-organic chemical vapor deposition (MOCVD). The Fe ion concentration distribution within a single nanotip is mapped by electron energy loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) and the nanotips imaged by high-resolution transmission electron microscopy (TEM). X-ray absorption spectroscopy (XAS) identified the presence of Fe 2+ and Fe 3+ ions in both as-implanted and annealed samples. However, Fe 3+ ion concentration increased during postannealing. Superconducting quantum interference device (SQUID) measurements show that the as-implanted and postannealed ZnO nanotips are ferromagnetic at room temperature. The observed ferromagnetism in the as-implanted nanotips is primarily attributed to the near surface 10-nm region that has high Fe concentration. The saturation magnetization reduces after annealing.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry