Effects of different valence atoms on surface passivation of silicon carbide nanowires

In this paper, based on the first principles, we study the properties of silicon carbide nanowires (SiCNWs) passivated by monovalent hydrogen (H), heptavalent fluorine (F) and chlorine (Cl) atoms at the electronic level to reveal the mechanism of interaction between different valence electrons in the passivation process. The results show that the passivation can improve the inhomogeneity of the surface and internal Si–C bonds, and improve the stability of the SiCNWs structure. The structure of F-SiCNWs is the most stable. Meanwhile, passivation increases the bandgap of the SiCNWs, and the bandgap of H, F and Cl passivation SiCNWs decreases successively, this is because the potential energy of H-1s, F-2p and Cl-3p interacting with Si-3p decreases in turn. Besides, heptavalent F and Cl passivation can regulate some optical properties of the SiCNWs to the deep-ultraviolet light regions such as absorption, conductivity, refractive index and loss function. Monovalent H passivation can regulate some optical properties of the SiCNWs to the vacuum ultraviolet light region (UVD). These studies have potential application value for the development of deep-ultraviolet micro–nano devices.