Comparison on Photoluminescence and Magnetism between Two Kinds of Undoped ZnO Nanorods

We carried out a detailed comparison on the defect-related photoluminescence and magnetism in two kinds of undoped ZnO nanorods synthesized by low-temperature chemical bath deposition and high-temperature chemical vapor deposition methods to clarify further the nature of visible emission and d(0) ferromagnetism in ZnO based on the fact that these two kinds of ZnO nanorods have significantly different crystallinity and defect states. The results obtained by analyzing X-ray diffraction, electron paramagnetic resonance, and Raman scattering show that the intrinsic ferromagnetism in ZnO nanorods is originated from the single ionized oxygen defects (vacancies and interstitials). Particularly, it is demonstrated that the lattice disorder along the c-axis along with the introduced oxygen interstitials can boost ferromagnetism and induce the red-shift in visible emission.