| This thesis focuses on the improvement of techniques in synthesizing ZnO nanostructures in physical vapor deposition process and characterization of the synthesized nanostructures by electron microscopy techniques. Two goals have been achieved. First, the interface structure between substrate and aligned ZnO nanowires were examined by employing the ultramicrotomy technique to prepare cross-sectional TEM samples. It is observed that, a layer of nanowall-like structure grew first on the mica substrate, and the aligned ZnO nanowires grew on top of the nanowalls. Second, an easy-to-handle sealing system of the tube furnace reactor was developed to better control the carrier gas composition of the tube reactor. With the change of the stoppers of the reactor tube, the sealing of the whole system was greatly improved. Thus Zn nanostructures were synthesized. The effect of O2 on the ZnO nanostructure was discussed. |
