Study On Preparation And Optical Properties Of Composite Microstructured Silicon

Silicon material is widely used in solar cells and photodetectors due to its semiconducting properties.However,the average reflectivity of planar silicon for light in the 380 nm-1100 nm band is 40%,and the band gap of silicon is 1.12 e V,which makes it transparent to light with wavelengths greater than 1100 nm.These properties limit the wider range of silicon-based devices.Applications.In order to improve the light absorptivity of silicon in the visible and near-infrared bands,starting from three microstructures of silicon and surface plasmon effects,through simulation and experiments,a high absorptivity in the 380 nm-2500 nm band was designed and fabricated.composite microstructured silicon.The main work of the paper includes the following aspects:1.Use simulation software to establish the deposition model of microstructured silicon,composite microstructured silicon and silver/aluminum nanoparticles on composite microstructured silicon,and calculate and analyze the influence of various parameters on the light absorption rate.The results show that the microstructured silicon with larger feature size,surface occupancy and depth has higher absorptivity in the 380nm-1100 nm band;the composite microstructured silicon with nanopores has a higher absorptivity in the 380 nm-1100 nm band than the single microstructured silicon.The structure is higher,and the increase of the aperture increases first and then decreases the improvement of the light absorption rate.The introduction of silver/aluminum nanoparticles significantly enhanced the absorption rate of silicon in the 1100 nm-2500 nm band,and the absorption curve of silver particles-composite microstructured silicon was relatively flat.2.Microstructure silicon preparation and research.Four pyramid-shaped,spoonshaped and nanoporous microstructured silicon were prepared,and the effect of process parameters on morphology and spectrum was investigated.The results show that the absorption spectrum and morphology are closely related,depending on the reaction temperature,time,particle deposition and other factors.Tuning the process parameters can optimize the morphology and increase its density.3.Preparation and research of composite microstructure silicon.On the basis of simulation research,the preparation process of single microstructured silicon was optimized and combined to design and prepare nanopore-square pyramid composite microstructured silicon and nanopore-spoon-shaped composite microstructured silicon,and carried out morphological and spectral characterization.By controlling the etching time,the depth and density of the nanopores can be increased while avoiding the collapse of the microstructure,resulting in a higher absorption rate in the 380 nm-1100 nm band.4.Experimental preparation and research of silver nanoparticles-composite microstructured silicon.According to the simulation results,silver nanoparticles were deposited on the composite microstructured silicon,and the surface plasmon effect was used to improve the absorption rate of the composite microstructured silicon in the 1100nm-2500 nm band.Silver nanoparticles were prepared on the surface of composite microstructured silicon by magnetron sputtering,and the effect of sputtering time on deposition and overall absorption spectrum was studied.The results show that increasing the sputtering time increases the particle size and bonds.By adjusting the sputtering time,large-sized and separated silver particles can be obtained,the surface plasmon effect is enhanced,and the absorption rate of silver nanoparticles-composite microstructured silicon in the 1100 nm-2500 nm band is higher.The nanopore-square pyramid composite microstructured silicon finally prepared has an average absorption rate of 91% in the 380 nm-1100 nm band,and the nanoporespoon composite microstructured silicon has an average absorption rate of 93% in the 380nm-1100 nm band,the average absorption rate of silver nanoparticles-composite microstructured silicon in the 380 nm-2500 nm band is 97%.