Transition voltage spectroscopy of porphyrin molecular wires.
Measurements are presented of the current-voltage (I-V) characteristics of individual thiol-tethered porphyrin molecules (isolated in an alkanethiol matrix) and of self-assembled monolayers. In both cases, it is found that I/V(2) displays a minimum at a characteristic "transition voltage" V(m). Repeated measurements of the transition voltage enable both its time development and statistical behavior to be determined. For isolated molecules, the transition voltage shows a multipeaked distribution of values, indicating the presence of a small number of distinct molecular/contact configurations, each having different transport characteristics. For self-assembled monolayers, in contrast, a single-peaked distribution was observed, which is consistent with parallel conduction through many molecules.
School of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3AA, UK. bennettn1@cardiff.ac.uk
Neil
N
Bennett
Gengzhao
G
Xu
Louisa J
LJ
Esdaile
Harry L
HL
Anderson
J Emyr
JE
Macdonald
Martin
M
Elliott
D019281:Dimerization; D016252:Microscopy, Scanning Tunneling; D011166:Porphyrins / Q000737:chemistry*
D011166:Porphyrins