Nanografting of thiols on a Au(111) surface. 1.5µm scan courtesy of M. Liu and G. Liu, UC Davis.
The sample was the surface of a gold crystal (Au(111)) covered with a self assembled monolayer (SAM) of decanethiol (CH3(CH2)9SH). Imaging was done under liquid in a solution containing octadecanethiol (CH3(CH2)17SH). The lithography was done by applying a (approximately 10X) higher force during writing. This displaced the decanethiol molecules, which were then replaced in the SAM by the longer octadecanethiol molecules. The surface is higher where written because the tails of the octadecanethiol molecules stick up above the average height of the SAM. Total size of the spirals is 620nm. Average line spacing is 40nm and average line-widths (FWHM) are 15 to 20nm.
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