Study On Enhanced Fluorescence Properties Of Ag/CdS Composite Nanowires

Recently,One-dimensional?1D?semiconductor nanomaterials,such as nanowires,nanorods and nanotubes,have become a focus of intense research as building blocks for future nanodevices and an ideal platform for the fundamental physical research in nanoscale.They not only have novel physical properties and applications in the fabrication of nanoscale devices,but also they are expected to be as interconnects and functional units in electronic,opto-electronic,and other devices with nanoscale dimensions.Among these applications,the bandgap of the semiconductor nanomaterials is a crucial physical parameter to determine the basic performance of a device,such as the emission wavelength of LEDs and nanolasers.In the semiconductor nanomaterials of II-VI,Zinc Sulphide?Zinc Sulphide,ZnS?,Zinc Selenide?Zinc Selenide,ZnSe?,Cadmium Sulfide?Cadmium Sulfide,CdS?,Cadmium Selenide?Cadmium Selenide,CdSe?etc in nanodevices and opto-electronic devices have a wide range of application.This paper mainly studies the enhanced fluorescence properties of Ag/CdS composite nanowires.The details are as follows:1.The source of the thesis is expounded.The optical properties and applications of semiconductor nanomaterials and metal-semiconductor composite structures are described.CdS nanowires are synthesized by Chemical Vapor Deposition method?CVD?.X-ray Diffraction?XRD?is used to observe the properties of the phase and the elements of the sample structure.The surface morphology of the Ag/CdS composite nanowires is observed by the field-emission scanning electron microscope?SEM?and the atom force microscope?AFM?.2.The preparation of Ag/CdS composite nanowires.Firstly,the CdS nanowires are scattered on the surface of the quartz substrate;Then,the graphic of the mask version transfer to the photoresist by the photolithography process;Further,plating10nm thick magnesium fluoride?MgF₂?and 100nm thick silver film?Ag?by the electron beam evaporation deposition;Finally,photoresist is dissolved by acetone,thus,one half of the CdS nanowires is covered by Ag film,the remaining half is not covered.3.The optical test of Ag/CdS composite nanowires.Firstly,the experimental optical path diagram is designed,and the laboratory equipment is used to set up a confocal microscopy system.The optical test adopts a Ti sapphire femtosecond laser?Tsunami,Spectra-Physics,20fs and 80MHz?with the center wavelength of 800nm.Secondly,the fluorescence spectra and fluorescence lifetime of CdS nanowires with bare and Ag-coated,are tested respectively under the same test conditions;By changing the polarization direction of excitation light,the fluorescence intensity of CdS nanowires with bare and Ag-coated are tested respectively with different excitation light power,in addition,their nonlinear optical propersities are explored.