Effect Of Surface Passivation On The Structure And Electrical Properties Of SiC Nanowires

As a semiconductor material,silicon carbide has the characteristics of high critical breakdown field strength,high thermal conductivity,high electron saturation,wide band gap,small thermal expansion coefficient,small dielectric constant,good chemical stability,strong thermal stability and radiation resistance,so more and more scholars have paid attention to SiC nanomaterials.Moreover,excellent achievements have been made in the application of silicon carbide nanomaterials in laser,ultraviolet detector,microwave and millimeter wave power devices and other fields.There are a lot of broken bonds on the surface of SiCNWs,and these unsaturated suspended bonds will lead to the instability of electrical and optical properties of SiCNWs,which will restrict its application in micro and nano electronic devices.Surface modification is an effective way to improve the stability of performance.Stability,transport properties and dielectric properties are important properties in the development and application of SiCNWs micro-nano electronic devices.So in this paper,based on first-principles calculation,transport theory and polarization relaxation theory,2H-SiCNWs were systematically studied based on the First-principles calculation and semiconductor physics theory.The effects of different passivated atoms and groups on the structure,conductivity and dielectric properties of SiCNWs were studied.This study provides theoretical guidance for the regulation and application of silicon carbide in the future.The main contents of this paper are as follows:Firstly,the development history of semiconductor nanomaterials,the basic theory and simulation software involved are described in detail.Then,the CASTEP module was used to construct the structure of SiC nanowires,and the surface of SiC nanowires has been passivated by H atoms,F atoms and OH groups.The effects of passivation of different polar atoms and groups on the lattice structure and electrical structure of SiCNWs were studied by analyzing the structure data before and after passivation.Finally,the data of dielectric properties and conductance properties of the nanowires before and after passivation were numerically simulated according to the transport theory and the dipole relaxation model.The effects of different atomic passivation,temperatures and frequencies on the conductivity and dielectric properties of 2H-SiCNWs were investigated.The results show that the passivation improves the stability of SiCNWs,and the polarization occurs during the passivation process of polar atoms(groups).The passivation changes the surface electrical structure of the SiCNWs and the mobility of SiCNWS is closely related to its scattering mechanism.