Preparation And Performance Research Of Silicon-based Luminescent Materials

The bottle-neck of microeleetronics and the demand of the development of information technology have accelerated the research on optical information processing and optoelectronic integration on Si-based material.The success of high-quality Si based light sources will make a great impact on optoelectronic and information industry.However,the electronic structure of bulk silicon is a semiconductor material with indirect bandgap.This hinders the effective emission and absorption of light limits its optoelectronic application in the optical field owing to its slow carrier dynamics and photoluminescence intensity.Therefore,many researchers have improved the luminous efficiency of crystalline silicon through modification methods.Currently,porous silicon,silicon nanoparticles and silicon nanowires are feasible silicon luminescence pathways.Based on the existing problems of the silicon-based materials in the current stage,this paper mainly studies the preparation of porous silicon-based luminescent materials and the preparation of silicon nanoparticle luminescent materials.And the luminescence mechanism is further discussed by the influence of surface morphology on its optical properties,laying a foundation for the applications of silicon-based luminescent materials in the field of photoelectricity.The main findings and results are listed as follows:(1)The porous silicon wafers capable of emitting orange light and blue-violet light by metal-assisted chemical etching.Polycrystalline silicon wafers were used as raw materials,and HF and Ag NO3 solutions were used as etching solutions to etch the silicon wafers to prepare porous silicon wafers with fluorescent properties.Then the porous silicon wafer were prepared optical performance test and morphology testing.The four emission peaks of the porous silicon wafer were obtained at 330 nm,374 nm,468 nm,and 628 nm,respectively.Among them,the emission peak are located at ?=374 nm,?=628 are the most stable and strongest.It can be observed by SEM electron micrograph that the surface of the porous silicon wafer with the main emission peak at ?=628 nm is rough,but the pore growth is relatively uniform,and the pore size is small pore structure,and the pore size is about 40-50 nm.The porous silicon wafer near ?=374 nm has fewer pores on the surface,the pore size is about 145-160 nm,and there is no phenomenon of large pores.In addition,putting the prepared fluorescent porous silicon wafer in an air atmosphere,and the attenuation of the fluorescence intensity is weak,so that the prepared fluorescent porous silicon wafer can be stably existed in the air atmosphere.This research progress has potential application value for porous silicon in the field of optoelectronic integration.(1)Bright blue fluorescent silicon nanoparticles with good dispersibility and no organic group modification were successfully prepared by magnesium thermal reduction reaction and chemical etching.First,the silicon precursor is prepared by calcining at a high temperature in a strong reducing atmosphere using ethyl orthosilicate as a raw material.Then,the prepared silicon precursor is chemically etched to prepare silicon nanoparticles with high fluorescence performance and good dispersibility.Optical properties and structural tests were performed on the prepared fluorescent silicon nanoparticles.Fluorescent silicon nanoparticles have strong emission peaks around ?=443 nm,their particle size is about 2~4 nm,a spherical structure,and the prepared silicon nanoparticles have good crystallinity.Because the prepared silicon nanoparticles have the advantages of no organic group modification,strong fluorescence performance and good dispersibility,they have laid a foundation for its application in biomedicine.