Controlling stability and electronic properties of small-diameter SiC nanowires by fluorination

摘要

We report results of a density functional theory study of the electronic properties and stability of fluorine-saturated 0.355nm-thick silicon carbide nanowires with a 3C-SiC core and grown along the [111] direction. The electronic band gaps of the fully fluorinated SiC nanowires are lower than that of the corresponding fully hydrogenated ones by up to 1.09 eV. Moreover, the structural stability is found to increase linearly with fluorine surface covering. For mixed fluorination and hydrogenation surface decoration schemes, the band gaps usually lie between the values of the fully fluorinated and the corresponding fully hydrogenated nanowire. Furthermore, the band gap type changes from direct to indirect for fluorine coverings exceeding 16.66%. These results indicate that fluorination of the nanowire surface may be used to control the stability as well as the size and nature of the band gap.