IMAGING MOLECULAR DEFECTS IN ALKANETHIOL MONOLAYERS WITH AN ATOMIC-FORCE MICROSCOPE

Octadecanethiol (CH3(CH2)17SH) monolayers on sputtered gold have been imaged with an atomic force microscope. Octadecanethiol tended to form a hexagonal lattice with a lattice constant of 0.50 nm, despite the fact that the sputtered substrate was not crystalline gold(111). This indicates that packing of octadecanethiol on gold is dominated by the hydrocarbon chains. By imaging in electrolyte solution or alcohol we reduced the force applied by the tip to the sample. In this way, different kinds of molecular defects and packing structures of the alkanethiol monolayer could be imaged.