AVS 49th International Symposium
    Nanometer Structures Wednesday Sessions
       Session NS+EL-WeA

Paper NS+EL-WeA8
Electrochemically Controlled Film Formation of Self-assembled Monolayers of Biphenyl-based Thiols

Wednesday, November 6, 2002, 4:20 pm, Room C-207

Session: Nanolithography & Self Assembly
Presenter: P. Cyganik, Jagiellonian University, Poland
Authors: I. Thom, StAndrews University, UK
B.J. Livesay, StAndrews University, UK
P. Cyganik, Jagiellonian University, Poland
M. Buck, StAndrews University, UK
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Usually self-assembled monolayers (SAMs) of thiols are prepared by mere immersion of the substrate in a solution containing the respective thiol. Whereas a number of preparation parameters such as the thiol concentration, temperature, immersion time, or solvent type have been investigated in some detail, no systematic studies have been performed on how the substrate potential affects the kinetics of film formation and the resulting SAM structure. Since the potential controls the bonding of a thiol to the substrate, i.e. its stability, the rate of adsorption/desorption and the mobility of the thiols are affected and, consequently, a pronounced influence of the potential can be expected. Using thiols which are characterized by a biphenyl unit and an alkane spacer chain between the aromatic moiety and the SH group we have studied the kinetics of film formation using nonlinear optical spectroscopies and scanning tunneling microscopy. Both the kinetics of film formation and the final film structure undergo significant changes ranging the potential from values near the reductive desorption of thiols to values around zero volts.