Influence Of Doping On The Structure And Properties Of Tetra-Pod Shaped ZnO Whiskers

In this thesis, the intrinsic defects and extrinsic defects of Tetra-pod shape ZnO (T-ZnO) whiskers were controlled and induced respectively. The micro morphology, crystal structure, electric conducting properties, optical properties and moisture sensitive characteristics of as-doped T-ZnO whiskers were measured and analyzed. The intrinsic defects concentration of ZnO was changed through heat treatment at 900℃ and annealing in air, N₂ and H₂ atmosphere respectively; Al, Fe, Ag were doped in T-Zno by solution absorption/physical blending pretreatment following by high temperature diffusing process. The micro morphology, the phase composition and crystal structure of as prepared samples were analyzed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and Inductively Coupled Plasma emission spectrometry (ICP) respectively. The result shows that Sn has influence on the morphology of T-ZnO which may results from c-axis preferred growth; Fe can be completely doped into ZnO crystal lattice and it substitution of Zn sites may only happens in (110) and (201) crystal plane of ZnO; Al tends to form ZnAl₂O₄ on the surface of T-ZnO While only small amount of Al can solid solutionized into ZnO lattice. The photo excitation properties and band structure of doped T-ZnO were measure through photo luminescence spectrometry (PL), which showed that induction of intrinsic defect has changed the energy band structure of T-ZnO. The electric conducting properties of the as-prepared doped samples were characterized by electric resistance tests and I-V curve, Fe and Ag doped T-ZnO show an electric resistance drop of three...