Formation of organic DDQ bilayer from DDQ monolayer

From the paper "Material for Massively parallel computing on an organic molecular layer," by Anirban Bandyopadhyay, Ranjit Pati, Satyajit Sahu, Ferdinand Peper, Daisuke Fujita, published in Nature Physics http://dx.doi.org/10.1038/nPHYS1636

The movie shows the formation of a bi-layer on Au (111) and detection of four states of DDQ. Prior to the DDQ deposition at room temperature (300K), the epitaxially grown Au (111) single crystal is periodically sputtered with an Argon (Ar) ion beam and annealed at 600K. The K-cell source temperature is kept at 500 K (melting point of DDQ is ~490 K). The surface coverage of molecules is less than 0.1% for 10 minutes of DDQ vapor deposition; this is increased to 100% with a deposition time of 20 minutes. To grow the bi-layer, the substrate is exposed to the 1 molecular DDQ vapor for 25 minutes. All STM experiments are carried out at 300 K. The DDQ monolayer binds to the Au (111) substrate as nitrogen shares its lone pair of electrons with the s orbitals of the gold. In the second layer, DDQ adsorbs at the junction of three DDQs of the first monolayer. Herring-bone like orientations of DDQs are created in the second layer as revealed from the conductance image.

Category:

Science & Technology

Tags:

• organic chemistry
• molecule deposition
• STM
• science
• physics