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 completed text measures 2 x 2 nanometers, which is roughly 40,000 times smaller than the width of the average human hair.
“It’s not possible to write any smaller than this,” said Masayuki Abe, a researcher involved in the project.
The ability to incorporate individual atoms into a surface could lead to a variety of advances in atomic scale technology, the researchers suggest. If used in chip manufacturing, for example, this technology could help build powerful computers the size of a wristwatch.