The Synthesization Of Co-doped ZnO Matrix Diluted Magnetic Semiconductors Using The Sol-gel Process

Diluted magnetic semiconductors (DMSs) is a new kind of semiconductors materials combining the carrier's spin degree of freedom with charge degrees of freedom. The research on diluted magnetic semiconductors has become one of the hot topics because of its new characters such as magneto-optical, magneto-electric, magnetic transport and its application prospect. As a wide band-gap semiconductor with prefer physical and chemical characteristics, ZnO can be used as the matrix of DMSs to obtain room-temperature ferromagnetism. And room-temperature (RT) ferromagnetism has been predicted in Co-doped ZnO.In this thesis, transition metallic ions(Co²⁺) were introduced into ZnO -based DMSs powder material by sol-gel method, and the RT ferromagnetism of Zn_1-xO:Co_x samples was achieved successfully. The influence of the synthesis condition on the structure and magnetism characteristic of Zn_1-xO:Co_x had been studied systematically through orthogonalizing design method and single factor experiments.The component, structure and magnetism of these samples have been characterized by XRD and VSM. The results of the experiment show that the wurtzite crystal structure of ZnO was not changed by the Co-doping, but the crystal quality was poorer with the increasing of Co-doping. The RT ferromagnetic behavior probably enhanced with fast annealing processing.The analysis of the test result of the samples magnetic and the magnetic property of monoatomic cobalt and cobalt oxide suggests that the ferromagnetism of the samples does not come from the secondary phase, but the intrinsic property of the Co-doped DMSs, Moreover, the magnetism of the samples was analyzed, and the magnetic property difference among the samples prepared with different parameters was explained reasonably based on n-carrier induced-double exchange mechanism.