Synthesis and Optical and Magnetic Properties of Diluted Magnetic Semiconductor Zn_1−<i>x</i>Mn_<i>x</i>O Hollow Spherical Structures

Abstract

A simple chemical vapor deposition technique has been employed to realize Zn1−xMnxO hollow spherical structures with room temperature ferromagnetism. We propose a special experimental scheme for the appropriate growth temperature, which could not only realize effective evaporation of the source materials, but also make further vaporization of the Zn enclosed in the Mn-doped ZnO layer and avoid the formation of Mn-related oxides on the substrates. A series of controlled experiments have been carried out for better understanding the formation mechanism. The morphology, structure, and composition have been investigated by field-emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and energy dispersive X-ray analysis, indicating that Mn2+ was successfully substituted into the Zn2+ site. Raman results show an additional mode (520−530 cm−1) in the doped samples due to the lattice defects triggered by Mn doping. Multipeak Gaussian fitting of the photoluminscence spectra exhibits an emission related to the d−d transition of Mn2+ from the ground state 6A1(G) to the excited state 4E(G). The origin of the room temperature ferromagnetism has been attributed to the magnetic coupling between Mn atoms.