2 research outputs found
Ultralow-Power Electronic Trapping of Nanoparticles with Sub-10 nm Gold Nanogap Electrodes
We
demonstrate nanogap electrodes for rapid, parallel, and ultralow-power
trapping of nanoparticles. Our device pushes the limit of dielectrophoresis
by shrinking the separation between gold electrodes to sub-10 nm,
thereby creating strong trapping forces at biases as low as the 100
mV ranges. Using high-throughput atomic layer lithography, we manufacture
sub-10 nm gaps between 0.8 mm long gold electrodes and pattern them
into individually addressable parallel electronic traps. Unlike pointlike
junctions made by electron-beam lithography or larger micron-gap electrodes
that are used for conventional dielectrophoresis, our sub-10 nm gold
nanogap electrodes provide strong trapping forces over a mm-scale
trapping zone. Importantly, our technology solves the key challenges
associated with traditional dielectrophoresis experiments, such as
high voltages that cause heat generation, bubble formation, and unwanted
electrochemical reactions. The strongly enhanced fields around the
nanogap induce particle-transport speed exceeding 10 μm/s and
enable the trapping of 30 nm polystyrene nanoparticles using an ultralow
bias of 200 mV. We also demonstrate rapid electronic trapping of quantum
dots and nanodiamond particles on arrays of parallel traps. Our sub-10
nm gold nanogap electrodes can be combined with plasmonic sensors
or nanophotonic circuitry, and their low-power electronic operation
can potentially enable high-density integration on a chip as well
as portable biosensing
Individual Template-Stripped Conductive Gold Pyramids for Tip-Enhanced Dielectrophoresis
Gradient fields of optical, magnetic,
or electrical origin are
widely used for the manipulation of micro- and nanoscale objects.
Among various device geometries to generate gradient forces, sharp
metallic tips are one of the most effective. Surface roughness and
asperities present on traditionally produced tips reduce trapping
efficiencies and limit plasmonic applications. Template-stripped,
noble metal surfaces and structures have sub-nm roughness and can
overcome these limits. We have developed a process using a mix of
conductive and dielectric epoxies to mount template-stripped gold
pyramids on tungsten wires that can be integrated with a movable stage.
When coupled with a transparent indium tin oxide (ITO) electrode,
the conductive pyramidal tip functions as a movable three-dimensional
dielectrophoretic trap which can be used to manipulate submicrometer-scale
particles. We experimentally demonstrate the electrically conductive
functionality of the pyramidal tip by dielectrophoretic manipulation
of fluorescent beads and concentration of single-walled carbon nanotubes,
detected with fluorescent microscopy and Raman spectroscopy