Influence of post-annealing on the structure and optical properties of ferromagnetic Zn1−xMnxO film prepared by PECVD technique

Room-temperature ferromagnetic Mn-doped ZnO films have been deposited on Si(0 0 1) substrates by plasma enhanced chemical vapor deposition technique. The microstructure, structure, optical and magnetic properties were investigated systematically. X-ray diffraction and transmission electron microscopy reveal that the all samples have a wurtzite polycrystalline structure and no secondary phase is found in films. Magnetization measurements indicate that Zn1−xMnxO films show room temperature ferromagnetism. In order to elucidate the origin of the ferromagnetism, Zn1−xMnxO films were annealed under different atmosphere. The results show that photoluminescence spectra are strongly dependent on defects in films and the interface between grains.