Bi atoms deposited on the Si (100) surface at temperatures higher than 400°C, form one-dimensional wires consisting of two chains of Bi dimers in the topmost layer. The dynamic process of Bi-nanowire formation has been investigated by scanning tunneling microscopy (STM) by performing in-situ observations at elevated temperatures. From the consecutive STM images taken after Bi deposition on the surface, we found that Bi-nanowires are formed by expelling atoms that compose an upper terrace at the front of Bi-nanowire growth. When Bi-nanowires are formed toward a lower terrace approaching its step edge, peninsulas are newly formed near the wires.
