Diameter-controlled synthesis of silicon nanowires using nanoporous alumina membranes

The use of nanoporous alumina membranes to control the diameter of silicon nanowires synthesized by vaporliquid-solid growth is demonstrated. An increase in nanowire diameter was observed when the nanowires grew out from the top surface of the membrane (see Figure). The diameter increase was attributed to a change in the shape of the Au-Si liquid alloy when the nanowires emerged from the membrane surface.