Nonlocal conductance modulation by molecules: scanning tunneling microscopy of substituted styrene heterostructures on H-terminated Si(100).
One-dimensional organic heterostructures consisting of contiguous lines of CF3- and OCH3-substituted styrene molecules on silicon are studied by scanning tunneling microscopy and ab initio simulation. Dipole fields of OCH3-styrene molecules are found to enhance conduction through molecules near CF3-styrene/OCH_{3}-styrene heterojunctions. Those of CF3-styrene depress transport through the nearby silicon. Thus the choice of substituents and their attachment site on host molecules provide a means of differentially tuning molecule and substrate transport at the molecular scale.
National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2V4, Canada.
Paul G
PG
Piva
Robert A
RA
Wolkow
George
G
Kirczenow