Vapor-phase Synthesis, Characterization And Photoluminescence Properties Of Nano-oxide (Ga₂O₃, ZnO) And Nano-sulphide (ZnS)

Recently, quasi-one dimensional nanomaterials such as nanotube, nanowire, nanocable, present a series of excellent properties due to their special nanostructure. They have attracted considerable attention for their potential applications in the development of nanoscale electronic and optoelectronic devices; therefore, they become the focus of nano-material. In this paper, the point is to synthesize quasi-one dimensional nanomaterials and to research the photoluminescence properties. We choose the simple thermal evaporation method. Compared with the others, the thermal evaporation method can be easily controlled; the product is simple in component, fine in crystal structure and the method can be widely used. The following are the main contents and conclusions:1. Research on synthesis, characterize and photoluminescence properties of Ga₂O₃ nanowhisker.With liquid Ga as source material, Si (111) as substrate, large qualities of Ga₂O₃ nanowhisker is synthesized by thermal evaporation. The average diameter of these nano whiskers is 70-100nm with smooth surface. Otherwise, we found many nanopieces, it may because the airproof in the tube is not good enough and the remnants oxygen exists, it formed the low oxygen supersaturation in the tube. For on liquid drop in the tip of the as-synthesis product in the SEM and TEM images, we think the growth of Ga₂O₃ nanowhisker follow VS process. Room-temperature photoluminescence measurement shows that the Ga₂O₃ nanowhisker had a blue emission at 467nm and a green emission at 520nm. It is suggested that the blue emission is attributed to gallium vacancies and gallium-oxygen vacancy pairs; the green emission originated from the recombination of different defects.2. Research on ZnS/SiO₂ coaxial core/shell nanocables with thermal evaporation.With the mixture of ZnS powder (99.999%) and SiO powder, we successfully synthesized the ZnS/SiO₂ coaxial core/shell nanocables with thermal evaporation. The ZnS core has a cubic sphalerite structure with the coexistence of periodically alternating twins along the [111] growth direction and stacking fault. The growth mechanism of the product follows a VS process. The diameter of the nanostructures was about 20-250nm. The room-temperature PL spectrum of our product show four emission band centering at about 548nm, 614nm, 649nm and 670nm, respectively, which may originate to the impure ZnS, existence of Si and oxide related defects.3. Reassure on synthesis, characterize of ZnO microcombs.Nanocomb is a good example of hierarchical nanostructures, can be applied to nanobracket. We synthesized the hexagonal wurtzite structure of ZnO comb-like and we explained the growth mechanism of this hierarchical structure with a sketch map. The comb stem is belt-like, growing along [110] direction, and the width is about 3μm, length tens of micrometers; the epitaxial comb teeth distributed even along one side of the comb stem and grew along [001] direction. The comb teeth are vertical to the comb stem; the width is uneven, from 30nm to 200nm, the length is about several micrometers.