SCANNING-TUNNELING-MICROSCOPY STUDIES OF SELF-ASSEMBLED MONOLAYERS OFALKANETHIOLS ON GOLD

Scanning tunneling microscopy was used to probe the molecular scale st ructures of pure and mixed composition self-assembled monolayers of CH 3(CH2)15SH and CH3O2C(CH2)15SH on gold. A predominant defect structure is found for both films, and is assigned as a void defect in the thio late overlayer. The mixed composition films are observed to phase segr egate into domains of the pure component thiolates. Time-lapse series of scanning tunneling microscope images reveal kink-driven motion at s tep edges and exchange of thiolate molecules on terraces.