video: This movie was recorded in a transmission electron microscope and it shows a silicon nanowire growing from a liquid droplet composed of gold, aluminum and silicon. The droplet is the dark semicircle, and the wire itself is a medium grey. The diameter of the wire is 26nm and the horizontal field of view of the movie is 130nm. The movie has been speeded up by 4x (which is why it is a bit jumpy in places). The wire is growing at high temperature, 570°C, and it grows at 24nm per minute. The growth rate depends on the amount of Si-containing gas we supply. You can see that the wire is growing by looking at the distance between the droplet and, say, the wide part of the wire (which we grew specially to give something to measure from; perfect wires have a steady diameter so are rather featureless and hard to measure!) You can also see small movements of the liquid droplet during growth. This video relates to an article that appeared in the Nov. 27 issue of Science, published by AAAS. The study, by Dr. C.-Y. Wen at Purdue University in West Lafayette, Ind., and colleagues, was titled, "Formation of Compositionally Abrupt Axial Heterojunctions in Silicon-Germanium Nanowires." view more
Credit: Videos courtesy of IBM