| Researches on nanocrystalline materials have increased enormously during the past years. In this field, the studies on semiconductor nanocrystal colloids are receiving large attention owing to their novel optical and electronic properties and to the several envisaged application areas (solar cells, light emitting diodes, photonic crystals etc.).The optical properties and the structure properties of nano- structure materials are studied with UV-Visible spectrometer, time-resolved spectrometer and near field scanning optical microscope. The preparations with chemical and physical method are done for the nano-materials that have potential applications when we comment on the development of them. Other research techniques such as TEM (transmission electron microscope) and X-ray diffraction instrument etc. are used, so we can study the nano-materials' qualities with different aspects.Surface chemical modification can change the surface states, together with size effect the optical properties of nano-materials are different from the bulk materials. We have prepared ZnO nano-collosol which is coated with DBS ( Dodecyl Benzene Sulfonate ) with the microemulsion method, the samples with different sizes disperse very well and can be found with TEM. The bandege emission is evident and the emission peak blueshifts in the photoluminescence spectra, these can be explained that the eigenstates of ZnO QD have important contribution. In our system, the organic coating occupies the surface sites and forms the surface potential barrier, which can prevent the formation of the surface states and hence the resonance radiation transition of the exciton dominates. This property will be eventually applied in the ZnO laser devices.ZnO is one of the important II-VI subgroup semiconductors withIVexcellent optical qualities, it has attracted both fundamental and technological interests to many researchers today because of their many applications in life. ZnO nano-semiconductor materials with different sizes are studied, wurtzite ZnO nano-crystal are prepared with the method of coprecipitation. We explore the properties of the ZnO under pressure and find that the nano-crystal has the domain destruction that belongs to the bulk materials before. This method supplies a kind of technique to prepare nano-crystals with different sizes. In order to verify the size changing with the pressure, X-ray diffraction graphs of the ZnO nano-crystal are given.Long-lived phosphor SrOiA^OsiEu are prepared with sol-gel method. The rare-earth luminescence material SrO:Al2O3:Eu with different sizes by the control of the pH values are obtained. This material has extensive applications in the optical thin films This kind of material can produce phosphorescence radiation for more than one decade hours under the shining of some light source. In engineering plastics, it can largely decrease the ultraviolet light absorption and elongate the life-time of the plastic. It can shorten the growth period of the farm crops because of their luminescence. The rare-earth luminescence material SrOiA^OsiEu have comparatively broad fluorescence peaks, furthermore, the fluorescence peaks' positions changed with the pH values, these phenomena can be explained that the crystallinity is changed with pH value. The higher pH value, the better crystallinity, the grade of the crystallinity of materials influences the change of the photoluminescence of the material. There are still some mechanism problems unsolved for above phenomena.Near-field scanning optical microscope (NSOM) make use of principle of the near-field optics, it detects the information near the material' surface, and breaks through the limit of resolution and detects the microscopic structure information of the samples It forms the image with the photon, which is different from the other kinds of microscope that detect thesamples with electron or force. The study of luminescence mechanism and luminescence spatial distribution of the materials benefit from NSOM. In this paper, the NSOM' princip... |
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