Ab-initio study of anisotropic and chemical surface modifications of β-SiC nanowires
- 365 Downloads
The electronic band structure and electronic density of states of cubic SiC nanowires (SiCNWs) in the directions , , and  were studied by means of Density Functional Theory (DFT) based on the generalized gradient approximation and the supercell technique. The surface dangling bonds were passivated using hydrogen (H) atoms and OH radicals in order to study the effects of this passivation on the electronic states of the SiCNWs. The calculations show a clear dependence of the electronic properties of the SiCNWs on the quantum confinement, orientation, and chemical passivation of the surface. In general, surface passivation with either H or OH radicals removes the dangling bond states from the band gap, and OH saturation appears to produce a smaller band gap than H passivation. An analysis of the atom-resolved density of states showed that there is substantial charge transfer between the Si and O atoms in the OH-terminated case, which reduces the band gap compared to the H-terminated case, in which charge transfer mainly occurs between the Si and C atoms.
KeywordsNanowires Silicon carbide DFT Surface passivation
This work was supported by project PICSO12-085 from Instituto de Ciencia y Tecnología del Distrito Federal (ICyTDF), and multidisciplinary project IPN2012-1439 from Instituto Politécnico Nacional. The authors Alejandro Trejo and José Luis Cuevas would like to thank CONACYT for their student scholarships.
- 9.Wu R, Zhou K, Wei J, Huang Y, Su F, Chen J, Wang L (2012) Growth of tapered SiC nanowires on flexible carbon fabric: towards field emission applications. J Phys Chem C. doi: 10.1021/jp3028935
- 12.Longkullabutra H, Nhuapeng W, Thamjaree W (2012) Large-scale: synthesis, microstructure, and FT-IR property of SiC nanowires. Curr Appl Phys. doi: 10.1016/j.cap.2012.02.032
- 24.Cuevas JL, Trejo A, Calvino M, Carvajal E, Cruz-Irisson M (2012) Ab-initio modeling of oxygen on the surface passivation of 3CSiC nanostructures. Appl Surf Sci. doi: 10.1016/j.apsusc.2012.03.175
- 25.Hammer B, Hansen LB, Nørskov JK (1999) Improved adsorption energetics within density-functional theory using revised Perdew–Burke––Ernzerhof functionals. Phys Rev B 59(11):7413–7421Google Scholar