Preparation Of Single Crystal Silicon By MaCE Method Magnetoelectric Coupling Research On Nanopore Array

Silicon nanostructures have always been a research hotspot for researchers today.It has extensive and urgent application in high-tech industries such as solar cells,electrochemical energy storage,optical transmission systems,and photodetectors.The combination of single crystal silicon and nanotechnology makes it exhibit surface effects,quantum confinement effects,thermal stability and other special physical properties,which greatly increases the research value of monocrystalline silicon nanostructures in many fields and the research enthusiasm of researchers.Metal-assisted chemical etching(MaCE)has gradually become the mainstream process for nanostructure preparation due to its advantages of simple process,low cost,high efficiency and easy process control.The metal-assisted chemical etching method for preparing a single crystal silicon nanopore array is a galvanic cell reaction system composed of Si-H2O2-precious metal(Ag,Au,Pd).Various factors in the chemical system(precious metal size and type,etchant solution ratio,single crystal silicon characteristics,temperature and illumination)will affect the nanostructure morphology,which also makes the silicon nanopore array structure prepared by the method.There are characteristics such as poor quality and low repeatability.Therefore,this thesis proposes a magnetoelectric coupling to prepare a single crystal silicon nanopore array.Based on the MaCE method,combined with the external magnetoelectric coupling physics field,it breaks through the limitations of the chemical reaction system and provides a kind of single crystal silicon nanopore array.New ideas and achieved certain results.(1)The background and significance of the research topic are introduced from the application and preparation methods of single crystal silicon nanopore array and the research status at home and abroad is analyzed and summarized.(2)The MaCE reaction mechanism is described in detail,and detailed analysis is carried out from the mass transfer mode,the charge transfer process,and the hole transfer process.The mechanism of MaCE regulation is described in detail,focusing on the etching direction,etching rate and structure quality of nanostructures.(3)The stability of magnetoelectric coupling is analyzed by ANSYS.It is proved that the electromagnetism and magnetoelectricity do not generate eddy current in the experimental range,and the coupled field is stable and will not interfere with the experiment.And for experimental repeatability,the experimental platform,experimental steps and experimental specifications were designed.(4)A single crystal silicon nanopore array with excellent morphology and structure was successfully prepared by the method described in this paper.According to different experimental results,the effects of different factors on the preparation of single crystal silicon nanopore arrays were investigated.The effects of etching time and lateral dimension of the catalyst on the etching depth under the effect of magnetic field were also analyzed and the factors affecting the porosity of the single crystal silicon nanopore array were analyzed.And by applying different current densities to the etching process at different temperatures,the Arrhenius diagram of the process rate of metal-assisted chemical etching is generated,and the activation energy at different current densities is calculated.At the same time,in the experiment of preparing the three-dimensional Wiener structure by the magnetic field effect,we found that the multi-dimensional complex silicon nanostructure morphology can be realized by changing the direction of the magnetoelectric coupling force to control the movement of the metal catalyst,which is a complex three-dimensional micro-nano structure.Preparation provides a viable solution.