The Effect Of Layer Number On The Electronic And Optical Properties Of Few-Layer Silicon Carbide Nanosheets

Silicon carbide nanosheets(SiCNSs),as a member of two-dimensional materials,have many similarities with previously discovered two-dimensional materials and possess unique properties that other two-dimensional materials do not possess.SiCNSs have enormous potential in the fields of gas sensing,energy storage and conversion equipment,and quantum technology.Based on the first principle calculation of density functional theory,this paper studies the performance of few-layer SiCNSs(FL-SiCNSs)in two degrees of freedom:layer numbers and stacking order.The main contents are the following:Firstly,compare and study the effects of layers on the electronic properties,optical properties,and lattice structure of SiCNSs.FL SiCNSs are equally stable as single-layer SiCNSs.As the number of layers increases,the interlayer coupling effect increases,the overall conduction band narrows,the bottom of the conduction band decreases,and the bandgap decreases.For optical properties,There are three absorption peaks in the vertical direction of the absorption spectrum,4.35 eV,7.83 eV,and 11.68 eV.As the number of layers increases,the intensity of the absorption peak decreases overall;In the parallel direction,there is a strong absorption band between 2-10 eV.As the number of layers increases,the absorption band narrows and the strength shows a decreasing trend.In the parallel direction,it has suitable reflectance in the range of 170-440 nm and is a good material for making ultraviolet reflectors.Secondly,the effects of three different stacking order on the electronic properties,optical properties,and lattice structure of SiCNSs were compared and studied.Among the three stacking order,AB stacking order is the most stable SiCNSs.Under the same number of layers,the bandgap of the two AA stacking order SiCNSs is generally lower than that of the AB stacking order SiCNSs.For optical properties,in the parallel direction,the stacking order has almost no effect on the optical properties;In the vertical direction,the peak intensity or oscillation amplitude of the optical properties of AB-SiCNSs are stronger than those of the other two AA stacking order.The optical properties of AA-SiCNSs and AA’-SiCNSs are relatively similar,and simple changes to the stacking order have little impact on various properties under the same stacking order.Finally,a comprehensive study was conducted on the regulation of the structure,electronic,and optical properties of SiCNSs by changing the number of layers and stacking order.By adjusting these two degrees of freedom,SiCNSs with different performance can be obtained.These results provide some reference for the application of FL-SiCNSs in optical and electrical devices.