Structures and Energetics of Indium-Catalyzed Silicon Nanowires

Strong size dependent structures of Si nanowires, grown via indium nanoparticles, have been revealed by high-resolution transmission electron microscopy studies. It is found that, below the critical value of particle diameter of similar to 100 nm, the growth changes from < 111 > to predominantly < 211 > direction and the formation of multiple {111} twins changes from perpendicular to the < 111 > growth direction to parallel to the < 211 > axial direction. The growth mechanisms are discussed in terms of relative surface/interface energy, using Au catalyzed Si nanowires as a comparative benchmark.