Anisotropy in stability and Young’s modulus of hydrogenated silicon nanowires

To discern the anisotropy of silicon nanowires (SiNWs) grown in different directions, the binding energy, heat of formation, and Young’s modulus of hydrogen-passivated SiNWs with various diameters and crystallographic orientations were calculated using all-electron density functional theory. In the size range studied, nanowires grown in the [1 1 0] direction are most stable while those in the [1 0 0] direction are energetically least favorable. Similar trend was observed in the computed Young’s modulus. With the same radius, the nanowire along the [1 1 0] direction possesses the highest Young’s modulus, while the [1 0 0] wire has the lowest value.