Synthesis And Magnetic Properties Of ZnO Nanorods

Diluted magnetic semiconductor is a semiconductor that exhibit magnetic properties between a non-magnetic semiconductor and a magnetic element. With its charge and spin degrees of freedom accommodated into single matter, diluted magnetic semiconductor shows charming application prospect in related spintronic devices. Znic oxide (ZnO) has been considered one of the materials that are most promising for being used in spinning devices ever since a long time ago. In spite of great efforts, today this material still cannot be used in practical application, the main reason for which is believed to be the indefinition of the origin of magnetism, so that people cannot handle magnetism. At present, a large number of studies show that the defects within the oxide materials could be one of the major causes giving rise to the magnetism. In this paper, in order to change the defect distribution of ZnO, and control the magnetism of materials, pure ZnO nanorods were firstly synthesized by using a single-step aqueous solution route, which were then treated by hydrogen peroxide (H2O2) and ammonia, respectively. This thesis contains the following works and innovations:(1) Proper raw materials were selected to prepare the pure ZnO nanorods. X-ray diffraction (XRD) data confirms the wurtzite structure without any detected phase separations. Scanning electron microscopy (SEM) proves that the small-size grains of hexagonal wurtzite structure of ZnO oriented nearly homogeneous throughout the substrate.(2) Combined with Physical properties measurement system (PPMS), X-ray photoemission spectroscopy (XPS) and Photoluminescence (PL), the results show that the H2O2and ammonia treatment exert a great influence on the oxygen interstitials (Io) near the ZnO particles, and play an important role in tailoring the magnetic properties of ZnO.(3) We investigated the ferromagnetism of undoped ZnO, in order to preclude the influence of magnetic elements; The variation of magnetism was studied by using a simple low temperature solution treatment, free of considering the rapid variation of defects that might take place under high temperature. Also, this method could control the change of defect distribution within minimal range near the surface of material, which facilitates the study.