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Synthesis, Characterization And Optical Properties Of One-dimensional ZnO And Their Composite Nanostructures

Posted on:2009-02-18Degree:MasterType:Thesis
Country:ChinaCandidate:J F ZhongFull Text:PDF
GTID:2121360242998118Subject:Condensed matter physics
Abstract/Summary:PDF Full Text Request
One-dimensional ZnO nano-materials with high aspect ratio and quantum confinement effect had a comprehensive potential application in many areas, and more researchers focused on this compound semiconductor material.Zinc oxide with excellent performance had aroused widespread concern in new functional materials research and application. So the chemical vapor deposition combining with a sol-gel method had been used to synthesize different ZnO nanostructures (ZnO nanorods, Fe-doped ZnO nanostructures and Ag coated ZnO nanostructures) in different experiment condition. The effects of experiment condition on the growth of ZnO nanostructures systemically were studied, and the optical properties of these various ZnO nanostructures were also examined through photoluminescence spectra.The paper mainly includes three parts:(1) Zn(NO3)2 . 6H2O, citric acid and ethylene glycol used as raw materials. Different ZnO nanorod structures had been synthesized by chemical vapor deposition combining with a sol-gel method at different growth condition. The samples were investigated by XRD, SEM, TEM and PL. PL spectrum suggested that the products have a weak ultraviolet (UV) emission but a very strong and wide green emission. Interestingly, the UV emission of quadrangular nanorods showed a 5 nm red shift compared with the hexagonal one. The X-ray photoelectron spectroscopy was also carried out to demonstrate how the morphology influences the band structure and the reason of difference in green emission. Results of different condition indicated that the temperature, reaction time, catalyst, position of substrate and vapor supersaturation in the reaction play critical roles in formation of the products.(2) The transition metal doped zinc oxide could significantly reduce the resistance, which broadened the application field of zinc oxide. Based on these, we synthesis and characterization of Fe doped ZnO nanostructures by chemical vapor deposition combining with a sol-gel method. This work proved the feasibility of synthesizing doped ZnO nanostructures through our method. Our results indicated that Fe doped ZnO nanostructures show two luminescence peaks in the UV and green emission region, respectively. Lower energy shift of UV emission and green emission enhancement of RTPL were correlated with the results of XRD and XPS.(3) Silver nanomaterials displayed some unique activities in chemical, biological sensing and excellent properties in electricity, so Ag-modified nanostructures will provide a favorable approach to modulate their properties. Based on the synthesized hexagonal ZnO nanorods in first part work, we successfully synthesized Ag-coated ZnO nanostructures by adopting an appropriate amount of silver nitrate and ethylene glycol. The changes of silver particles with reaction time were researched, and the optical properties of Ag-coated ZnO nanostructures were compared with that of the pure ZnO nanostructures.
Keywords/Search Tags:zinc oxide, chemical vapor deposition, growth mechanism, composite nanostructures, photoluminescence
PDF Full Text Request
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