Twinning in TiSi2-island catalyzed Si nanowires grown by gas-source molecular-beam epitaxy

Using TiSi2 islands as a catalyst, we have grown Si nanowires by gas-source molecular-beam epitaxy using Si2H6 as the gas source. The dominant TiSi2 islands are C49 phase with the orientation: Si[110]//C49-TiSi2[100] and Si(001)//C49-TiSi2(010). Twinning in the grown Si nanowires is observed by reflection high-energy electron diffraction and transmission electron microscopy. The twining also causes kinking, i.e., an abrupt change of growth direction of the Si nanowires. Lattice mismatch stress between the TiSi2 islands and the Si nanowires possibly leads to twinning and kinking of the Si nanowires.