The Study Of Fabrication And Growth Mechanism Of ZnO Nanostructures By SS-CVD

Nanostructures ZnO materials have received broad attention due to their distinguished performance in electronics, optics and photonics. ZnO is a II-VI compound semiconductor which has many potential applications in short-wavelength optoelectronic devices, including light emitting diodes (LEDs) and laser diodes (LDs), ultraviolet detectors, high frequency and high power devices etc. With reduction in size, nanostructures ZnO materials exhibits more excellent performance compared with the bulk counterparts, which are largely believed to be the result of surface and quantum confinement effects. At the same time, novel electrical, mechanical, chemical and optical properties are introduced. So research into nanostructures ZnO materials has great significance not only for improvement in materials performance, but also for developing new generation nanodevices.In the dissertation, solid source chemical vapor deposition (SSCVD) technique was used to fabricate ZnO nanostructures materials. The structural, morphological, compositional and optical characteristics for the ZnO materials obtained here were investigated. Moreover, the formation mechanisms of the as synthesized nanostructures were elucidated. Listed below are the significant results achieved in this dissertation:1. By designing the technology of SSCVD, ball shaped, flowerlike, diamond shaped and rod shaped nanostructures of zinc oxide were successfully prepared. Among them, the ball shaped, flowerlike and diamond shaped ZnO structures were firstly reported.2. Ball shaped ZnO structures were divided into three types: solid balls, hollow balls and porous balls. They had the similar formation process and could be illuminated by Zn-ZnO Core-Shell model. The effects of different growth conditions on the morphology were evident. Rich oxygen concentration facilitated the formation of ball surfaces with large size crystals, while high thermolysis temperature favored the growth of big balls.3. Flowerlike ZnO structures had many novel and beautiful morphologies and most of them consisted of hexagonal petal crystals with tapering feature. Their growth mechanism could be explained by symmetrical nucleation and growth model. Different growth parameters had great effects on the morphology of flowerlike structures.4. Diamond shaped and rod shaped ZnO nanostructures could be interpreted by polar growth model. They had many similar properties: a tip on the top, hexagonal wurtzite phase structure, c-axis preferential oriented, single crystal character, [0001] axis direction and excellent optical performance.5. All the measurements demonstrated that ball shaped, flowerlike, diamond shaped and rod shaped nanostructures of zinc oxide had high purity, good crystallinity, few defects and excellent light emitting properties.