Zn-catalyzed growth processes and ferromagnetism of Mn-doped ZnO nanorods on Si substrate

► Vertically ZnO nanorods are fabricated on the substrate. ► Zn catalyst is used to induce the growth of ZnO nanorods. ► The FM originates from the Mn 2+-Mn 2+ ferromagnetic coupling. ► The growth of nanorods follows a VLS and self-catalyzed model. Well-aligned ZnO nanorods and Mn-doped ZnO nanorods are fabricated on Si (1 0 0) substrate according to the contribution of Zn metal catalysts. Scanning electron microscopy and high-resolution transmission electron microscopy images indicate that the influence of Zn catalyst on the properties of ZnO can be excluded and the growth of ZnO nanorods follows a vapor–liquid–solid and self-catalyzed model. Mn-doped ZnO nanorods show a typical room temperature ferromagnetic characteristic with a saturation magnetization ( M S ) of 0.273 μ B /Mn. Cathodoluminescence suggests that the ferromagnetism of Mn-doped ZnO nanorods originates from the Mn 2+–Mn 2+ ferromagnetic coupling mediated by oxygen vacancies. This technique provides exciting prospect for the integration of next generation Si-technology-based ZnO spintronic devices.