The Features And Applications Of The Surface Plasmon Of Metal Nanoparticles Near The Interface

With the rapid development of micro-machining technology and nanotechnology, surface plasmon technology has been widely used in optoelectronic devices on miniaturization and integration, and has been concerned in many fields, such as physics, chemistry, biology, medicine, and so on. Localized surface plasmons (LSPs) has an significant advantage of application in various fields because of the unique properties of propagation, excitation and localized surface electromagnetic field enhancements. Therefore, the researches on preparation of mental nanoparticles and characteristics of surface plasmon are in great importance.The main contents of this dissertation were organized as following:1. The characteristics of asymmetric light reflectance effect based on LSP.We found that there exist an asymmetric light reflectance effect, when light came from the up side and back side of the sample, respectively by some spectral measurement in experimental. In order to figure out what really it is, and what the influence factors are, we performed series of theoretical simulations through FDTD Solution software. We gained a similar reflection spectrum from FDTD.And the electric field distribution picture that obtained by FDTD simulation demonstrated that the intensity of electric field was much larger when light is incident from back side (SiO2side). This effect can be used for SERS substrate and biomolecular detector.The results of FDTD simulation also showed that this asymmetric light reflectance effect has nothing to do with the shape and size of metal nanoparticles, but relative with the different refractive index of the upper side and lower side of the surface of nanoparticles.FDTD analyze also shows that the ratio of the extinction peak intensities when light is incident from different directions equals to the ratio of the refractive indices of two mediums beside the interface wherever the Au nanoparticles half buried in the substrate or on the substrate, implying that when light is incident from the medium with higher refractive index, metallic nanostructures would have higher coupling efficiency with the incident light. This mechanism can be used to design and optimize LSP-based optoelectronic devices.2. Improve light extraction efficiency of DUV-LED by depositing Al nanoparticles on it.Deep-ultraviolet light-emitting diodes (DUV-LEDs) with emission wavelength ranging from200nm to350nm attract great attention due to their various applications in biomedical treatment, anti-fake identification, water and air purification, data store and military and so on. Compare with Blue-LED, the external quantum efficiency of DUV-LED is still in a low level. To improve light extraction efficiency of DUV-LED is in great importance.We obtained Al nanoparticles in small size and high density on Deep-ultraviolet light-emitting diodes (DUV-LEDs) by oblique-angle deposition method. And illustrate its feature of surface Plasmon by experimental and FDTD Solution software.For the sample which was deposited at a60°angle, the bottom emission shows an obvious red shift compared to the top emission.In this paper, we studied its mechanism through FDTD. The simulation result showed that the difference between the top-and bottom-emission wavelengths can be attributed to the substrate-induced Fano resonance effect of the Al nanoparticles.Here, we mainly do some research in the characteristics of Localized Surface Plasmon resonance about A1nanoparticles through FDTD simulation. The picture of extinction spectrum and electric field distribution shows a clear Fano effect. The electric field distribution and far-field radiation patterns indicate that when the light waves generated in the MQWs are coupled to LSPs, top and bottom emission can be improved.