| dc.description.abstract | This thesis compares the self-assembly of octanethiol, a representative
n-alkanethiol, with dithiothreitol (DTT) on Au (lll). Octanethiol is on
eight carbon n-alkanethiol while DTT is a four carbon Q ,(i) dithiol with
hydroxyl groups on the second and third carbons. We find that
octanethiol forms a densely packed c(4x2) superlattice of the
(/3*/3)R30deg. structure characteristic of n-alkanethiols. DTT forms a less
dense monolayer, possibly c(2/3x/3). Both monolayers exhibit pits 2.5 A
deep equivalent to the height of one gold layer. The time evolution of
pitting is investigated in both systems using scanning tunneling
microscopy (STM). The fraction of the surface that is covered by these
pits is found to be in the range of 0.05-0.10 for both systems and
consistent with previous n-alkanethiol studies. The mean pit radius
approaches an equilibrium value of ~19 A for both thiol species. It has
been observed that DTT modified systems do not reach this equilibrium
value as quickly as octanethiol modified systems. The nature of the
binding of DTT to gold is also investigated using STM and Auger electron
spectroscopy (AES) studies. AES studies involving Eliman's Reagent, a
marker species, suggest that a significant fraction of the DTT binds to
the gold surface via two Au-S bonds. | |
