Molecules
can serve as ultimate building blocks for extreme nanoscale
devices. This requires their precise integration into functional heterojunctions,
most commonly in the form of metal–molecule–metal architectures.
Structural damage and nonuniformities caused by current fabrication
techniques, however, limit their effective incorporation. Here, we
present a hybrid fabrication approach enabling uniform and active
molecular junctions. A template-stripping technique is developed to
form electrodes with sub-nanometer smooth surfaces. Combined with
dielectrophoretic trapping of colloidal nanorods, uniform sub-5 nm
junctions are achieved. Uniquely, in our design, the top contact is
mechanically free to move under an applied stimulus. Using this, we
investigate the electromechanical tuning of the junction and its tunneling
conduction. Here, the molecules help control sub-nanometer mechanical
modulation, which is conventionally challenging due to instabilities
caused by surface adhesive forces. Our versatile approach provides
a platform to develop and study active molecular junctions for emerging
applications in electronics, plasmonics, and electromechanical devices.