Investigation On Growth And Properties Of SnO₂ Micro/nano Structures On Patterned Sapphire And Si Substrates By CVD Method

SnO₂ is a new type of wide band gap（3.6 eV at RT） oxide semiconductor materials which is a kind of promising UV and blue light material. SnO₂ has been widely applied in many fields, such as gas sensors, optoelectronic devices and transparent conductive glass, and so on due to its high optical transparency in the visible range, low resistivity, and higher chemical and physical stability. In recent years, various one-dimensional（1D） nanostructures,such as nanobelts, nanotubes and nanowires one-dimensional nanostructures in a wide range of applications on optoelectronic devices, and which study also caused the wide attention of researchers. Therefore, investigation on preparation and characteristics of orderly SnO₂micro/nanostructures is the research hotspot and difficulty. In this thesis, the surface morphology, structural and optical properties of SnO₂ microhemispheres and nanowires on patterned sapphire and Si substrates by chemical vapor deposition method without using catalyst were investigated. The major research achievements are listed below:（1） Orderly SnO₂ microhemispheres with different sizes and regular array by changing the reaction source Sn powder mass were grown on patterned sapphire by CVD equipment without the use of any catalyst. This results were showed the diameter of SnO₂ microhemispheres were become larger and the crystal quality become badly with increasing Sn powder mass, and the special selective growth phenomenon of SnO₂ microhemispheres was found. In addition, we also found that the optical band gap of the samples were appeared red shift with increasing Sn powder mass. The preparation methods of choose patterned substrate for the preparation of high density, orderly arrangement of SnO₂micro/nanostructures provide a way feasible and effective method.（2） A long SnO₂ nanowires were synthesized on Si substrates by simple CVD method.The FE-SEM show that the SnO₂ nanowires with high density were obtained. The diameter of the nanowires is about 50-200 nm, and the length is about dozens micron. X-ray diffraction showed that SnO₂ nanowires were tetragonal rutile structure, and found no other impurities diffraction peak. This suggests that the samples were pure SnO₂ material. The oxygen vacancy defects peak located at 635 nm was observed in the photoluminescence spectrum.