A research team at Osaka University created an atomic pen
that can scribe nano-sized text on metal. The text of the writing is only 2 x 2 nanometers, or 40,000 times smaller than the width of an average human hair.
According to the researchers, whose results appear in the October 17 edition of Science magazine, the atomic pen is built on a previous discovery that silicon atoms at the tip of an atomic force microscope probe will interchange with the tin atoms in the surface of a semiconductor sample when in close proximity. Using this atom-interchange phenomenon, the researchers were able to arrange individual silicon atoms one by one on a semiconductor surface to spell out the letters "Si." The writing process, which took about an hour and a half to complete, was conducted at room temperature.
The graphic shows the letters "Si." that the scientists wrote with the atomic pen. (via CrunchGear