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nanotimes News in Brief

10-07/08 :: July/August 2010

Interfaces of Organic and Inorganic Materials // Pixel Letters out of Single Tin Atoms

P

rof. Dr. Michael Hietschold, chair of Solid Surfaces Analysis at Chemnitz University, Ger-

many, in cooperation with his PhD student Marius Toader developed a font whose pixel consist of single tin atoms that are located in the center of tin-phtha- locyanine molecules. The single letters have a size of only 4.5 x 4.5nm: the whole writing “TUC” is there- fore no longer than 18nm, and the lighter tin atoms only rise only 0.13nm in height.

“These molecules resemble tiny switches because the tip of the STM can virtually switch off the upward pointing tin atoms one by one on a molecular level, whereby the whole molecule turns inside out like an umbrella in the wind,” Hietschold explains. He goes on: “On the surface of a silver crystal there is indeed a checker board pattern alternating with the central tin atom pointing upward and tin-phthalocyanine molecules pointing downward.”

The investigation of single molecules and their inter- actions with specific surfaces – such as crystals out of silver, gold, or graphite – is one main focus of both Chemnitz scientists. The miniaturized writing was developed as part of Marius Toader’s thesis analyzi- ng interfaces of organic and inorganic materials with STM and STS.

http://www.tu-chemnitz.de/physik/AFKO/

Prof. Dr. Michael Hietschold, Phone: +49 (0) 371 531- 33203

Image: An ultra-thin, of one single molecular film consi- sting layer of tin-phthalocyanine molecules on a silver crystal – left, the original checker board pattern with punc- tual disorders before, and right, after the writing process. In the false color representation (below) the upward poin- ting tin atoms are emphasized. © TU Chemnitz/Chair

of Solid Surfaces Analysis