Controllable Fabrication Of Patterned Nanoparticles Based On Laser Interference

In recent years,micro-nano patterned nanoparticles?NPs?have received more and more attention and are widely used in plasmon resonance,surface enhanced Raman spectroscopy?SERS?,photocatalysis and high-density data storage devices.Laser interference lithography?LIL?can realize the fabrication of large-area,low-cost and periodic structures.Thus,it has extremely important applications in nanofabrication.When combined with other nanofabrication technologies,it will open a new way for patterned nanoparticle fabrication methods,thereby promote the research and application of new types of nanostructures and devices.This thesis is aimed at the development of micro-nano fabrication technology.Based on the analysis of laser interference light field and the interaction mechanism between the photon and the substrate material,the thesis combined the micro-nano fabrication methods of self-assembly such as light-induced electrochemical deposition and dewetting.The fabrication of patterned nanoparticles with multiple materials was achieved by functionalized interface control.A variety of characterization methods were used to analyze the coupling effects of optical-electric-magnetic multiphysical fields and the microscopic mechanisms.Based on this,the control of pattern distributions,sizes,and optical and magnetic properties of the generated nanoparticles was implemented by laser interference.This thesis focuses on the controllable fabrication technology of patterned nanoparticles based on laser interference.It has carried out the following research work.?1?Multi-beam interference field analysis and study of photon-material interaction mechanism.First,by analyzing the principle of multi-beam laser interference,the effects of the parameters of the multi-beam laser interference system on the distribution,period and contrast of two-beam and three-beam interference fields were studied,and a light-field distribution model was established.Secondly,by analyzing the instantaneous local photoelectric,photothermal,and photochemical effects on the micro/nano scale during the interaction between photons and materials,the mechanism of interaction between photons and substrate materials was studied.Two manufacturing mechanisms for patterned nanoparticles based on laser interference were determined,and two LIL system designs were completed according to the needs.?2?Study on laser interference controlled electrochemical micro-nano fabrication.By studying the laser interference controlled electrochemical deposition?LIED?method and mechanism,a LIED system model was established,and the influencing factors in the LIED process were theoretically analyzed.The controllable fabrication of micro-patterned Fe₃O₄ NPs was achieved in one step using the LIED method.The particle pattern was controlled by the interference light field distribution,and the synthesis of the particle was controlled by the interference intensity and the electrochemical deposition conditions?potential and deposition time?.?3?Research on micro-nano manufacturing mechanisms based on direct laser interference ablation?DLIA?and dewetting method.The formation mechanism of functional dewetting surface of micro/nano structures fabricated by DLIA was studied.The physical relationship between the surface nanostructure roughness and spinodal dewetting mechanism was studied.The formation mechanism of patterned metal nanoparticles was analyzed.Using the DLIA and templated dewetting methods,the controlled fabrication of patterned Au-Ni bimetallic nanoparticles was achieved.The effect of laser interference fluence on the nanostructure roughness and particle size distribution was analyzed and determined.The relationship between the surface dewetting property and laser interference fluence was established.In addition,the structural properties,magnetic properties,and magnetic domain distribution characteristics of patterned Au-Ni nanoparticles were studied.?4?Patterned magnetic core–shell nanoparticle arrays and their SERS applications.The SERS mechanism of magnetic-plasmonic core-shell nanoparticles was studied.By adjusting the components of nanoparticle core-shell structures,the dielectric constant of the system was changed,and a tunable plasmon resonance was obtained.The DLIA and dewetting methods were used to prepare large-area Ni@Au core-shell NPs SERS substrates with tunable composition.The magnetic and SERS properties of Ni@Au core-shell nanoparticles with different compositions were examined and analyzed.The SERS mechanism of Ni@Au nanoparticles was analyzed and verified based on the magnetic properties,and the optimal SERS performance was obtained.