Study On Silicon Nanostructures By Metal Assisted Chemical Etching With Magnetic Effect

Research on nanostructures is a hot research field in the forefront of science and technology development.And silicon nanostructure in the field of nanomaterial is one of the important disciplines.At present,silicon nanostructure has a very important role,which draws attention by virtue of its superior physicochemical properties,optoelectronic properties,thermal stability and surface properties.Nowadays,there are many ways to fabricate silicon for nanostructures.Due to its unique advantages,the metal-assisted chemical etching(Ma CE)has become one of the main methods for fabricating silicon nanostructures.The process of fabricating silicon nanostructure by Ma CE is essentially to etch single crystal silicon in the reaction chemical system.However,it is difficult to accurately grasp the correlation and mutual control of the internal variable parameters(For example,precious metal types and topographies,etchants,intrinsic properties of Si substrates,temperature and light,etc.)of the chemical reaction.This leads to many uncertainties in the process of preparing silicon nanowire structures,which also makes the process method have the problems of low repeatability in accurately fabricating silicon nanostructures.Therefore,the original chemical etching system regulates the preparation of silicon nanostructures need to conduct more in-depth study.In this paper,according to the mechanism of fabricating silicon nanostructures by electrochemical corrosion of Ma CE,a magnetic field is incorporated into the Ma CE to fabricate a silicon nanostructure under the action of magnetic effect.In order to overcome the limitation of the chemical reaction system,this paper provides a new controllable fabrication of silicon nanostructures.This paper discusses in detail the influences of magnetic effects,magnetic field strength,and Ag deposition time and oxidant concentration on the morphology of silicon nanostructures and their effect on surface subtractive properties.The main contents of this paper are as follows:(1)The background and significance of the subject is introduced.The methods of fabricating silicon nanostructures based on the metal-assisted method and the application of silicon nanostructures are summarized.(2)Introduced Ma CE etching mechanism in detail.According to the mechanism of Ma CE mechanism leads to the regulation of morphology of nanostructure of silicon,focusing on the regulation of the direction of nanowires,etching rate factors.According to the above mechanism summarizes the current technical difficulties of Ma CE.The idea of introducing magnetic field into Ma CE is introduced.The effect of magnetic effect on the etching reaction is analyzed emphatically,which provides the theoretical basis for the subsequent research.(3)Experimental research.Experimental groups were set up to examine the effect of the magnetic field incorporation on the formation of silicon nanostructures.Using the single variable method,four different experimental groups were set up to investigate the influence of four factors on the silicon nanostructures respectively and provide experimental verification support points for subsequent qualitative analysis of the four factors.Finally,the experimental instruments used,experimental reagents and experimental specific processes are described.(4)According to the SEM images of the experimental results,the influences of magnetic effect and magnetic field,the deposition time of Ag and the concentration of oxidant on the morphology of silicon nanostructures under magnetic effect were analyzed in detail.The main evaluation system is the SEM images of silicon nanostructures and the reaction's etch rate.The magnetic effect can promote the fabricating of silicon nanowires.The magnetic field strength can accelerate the etching rate and improve the effective depth of the silicon nanostructures.At the same time,a model of fabricating the silicon nanowires by Ma CE with magnetic effect is given.Within a certain range of magnetic effect,the Ag deposition time directly affect the gap and spacing between the silicon nanowires and the oxidant concentration can accelerate the etching rate and improve the length of the silicon nanostructures.By analyzing the experimental results,the optimal magnetic field strength,Ag deposition time and oxidant concentration under the magnetic effect can be obtained.(5)By introducing the anti-reflection theory of silicon nanostructure,the influence of magnetic effect and magnetic field,the deposition time of Ag and the concentration of oxidant on the surface anti-reflection of nanostructured silicon were analyzed.Finally,through the comparative analysis,the conditions of obtaining the lowest reflectivity and optimizing the preparation process are obtained.