AVS 52nd International Symposium
    Surface Science Wednesday Sessions
       Session SS+EM-WeM

Paper SS+EM-WeM1
Investigation of Mixed Fluorocarbon/Hydrocarbon Self-Assembled Monolayers on Au by Reactive Ion Scattering Spectrometry

Wednesday, November 2, 2005, 8:20 am, Room 202

Session: Self-Assembled Monolayers
Presenter: X. Yang, University of Arizona
Authors: X. Yang, University of Arizona
S. Ravindran, University of Texas
A. Graham, University of Arizona
K. Nebesny, University of Arizona
T.R. Lee, University of Houston
N.R. Armstrong, University of Arizona
V.H. Wysocki, University of Arizona
Correspondent: Click to Email
A series of mixed self-assembled monolayers (SAMs) of CF@sub 3@CF@sub 2@(CH@sub 2@)@sub 14@SH (C16F2) and CH@sub 3@(CH@sub 2@)@sub 15@SH (C16) were prepared on polycrystalline gold. Surface composition and crystallinity were first examined by XPS, FT-RAIRS and contact angle. Homogeneously mixed and well-ordered surfaces were formed. Results showed that surface composition followed solution composition uniformly. Reactive Ion Scattering Spectrometry (RISS) utilizing low-energy (<100eV) ion-surface collisions was used to investigate the mixture monolayers. Experiments are carried out in a tandem quadruple mass spectrometer. Precursor ions selected by the first quadrupole collide onto the surfaces at given collision energies. Neutralization and fragmentation of projectiles, ion-surface reaction and sputtering of surface species occur upon collision of the projectile ions with the surface. Product ions are extracted and analyzed by the second quadrupole. Benzene, tungsten hexcarbonyl and d4-pyrazine positive radical ions were used as projectile ions. As C16F2 concentration increases on the surface, projectile neutralization decreases, the amount of methyl/hydrogen abstraction decreases non-linearly, and linear increases of translational to internal energy conversion upon collision of either benzene or tungsten hexcarbonyl are shown. RISS shows high sensitivity to composition and homogeneity of surfaces.