Figure 1

a Transmission electron microscopy (TEM) image of nanowire and its tip. Energy dispersive spectrometer (EDS) analysis shows that nanowire consists of silicon and that the tip of nanowire is mostly composed of silicon and nickel that was used as a catalyst during the chemical growth. b TEM image of silicon nanowire and its tip. TEM image shows that silicon nanowire is chemically grown in the (111) direction, and so does the tip of nanowire