5 research outputs found
Graphene for True Ohmic Contact at MetalāSemiconductor Junctions
The rectifying Schottky characteristics
of the metalāsemiconductor
junction with high contact resistance have been a serious issue in
modern electronic devices. Herein, we demonstrated the conversion
of the Schottky nature of the NiāSi junction, one of the most
commonly used metalāsemiconductor junctions, into an Ohmic
contact with low contact resistance by inserting a single layer of
graphene. The contact resistance achieved from the junction incorporating
graphene was about 10<sup>ā8</sup> ā¼ 10<sup>ā9</sup> Ī© cm<sup>2</sup> at a Si doping concentration of 10<sup>17</sup> cm<sup>ā3</sup>
Babinet-Inverted Optical YagiāUda Antenna for Unidirectional Radiation to Free Space
Nanophotonics
capable of directing radiation or enhancing quantum-emitter
transition rates rely on plasmonic nanoantennas. We present here a
novel Babinet-inverted magnetic-dipole-fed multislot optical YagiāUda
antenna that exhibits highly unidirectional radiation to free space,
achieved by engineering the relative phase of the interacting surface
plasmon polaritons between the slot elements. The unique features
of this nanoantenna can be harnessed for realizing energy transfer
from one waveguide to another by working as a future āoptical
viaā
Porous PVDF As Effective Sonic Wave Driven Nanogenerators
Piezomaterials are known to display enhanced energy conversion efficiency at nanoscale due to geometrical effect and improved mechanical properties. Although piezoelectric nanowires have been the most widely and dominantly researched structure for this application, there only exist a limited number of piezomaterials that can be easily manufactured into nanowires, thus, developing effective and reliable means of preparing nanostructures from a wide variety of piezomaterials is essential for the advancement of self-powered nanotechnology. In this study, we present nanoporous arrays of polyvinylidene fluoride (PVDF), fabricated by a lithography-free, template-assisted preparation method, as an effective alternative to nanowires for robust piezoelectric nanogenerators. We further demonstrate that our porous PVDF nanogenerators produce the rectified power density of 0.17 mW/cm<sup>3</sup> with the piezoelectric potential and the piezoelectric current enhanced to be 5.2 times and 6 times those from bulk PVDF film nanogenerators under the same sonic-input
Full Surface Embedding of Gold Clusters on Silicon Nanowires for Efficient Capture and Photothermal Therapy of Circulating Tumor Cells
We report on rapid thermal chemical vapor deposition
growth of silicon nanowires (Si NWs) that contain a high density of
gold nanoclusters (Au NCs) with a uniform coverage over the entire
length of the nanowire sidewalls. The Au NC-coated Si NWs with an
antibody-coated surface obtain the unique capability to capture breast
cancer cells at twice the highest efficiency currently achievable
(ā¼88% at 40 min cell incubation time) from a nanostructured
substrate. We also found that irradiation of breast cancer cells captured
on Au NC-coated Si NWs with a near-infrared light resulted in a high
mortality rate of these cancer cells, raising a fine prospect for
simultaneous capture and plasmonic photothermal therapy for circulating
tumor cells
Large Thermoelectric Figure-of-Merits from SiGe Nanowires by Simultaneously Measuring Electrical and Thermal Transport Properties
The strongly correlated thermoelectric properties have
been a major
hurdle for high-performance thermoelectric energy conversion. One
possible approach to avoid such correlation is to suppress phonon
transport by scattering at the surface of confined nanowire structures.
However, phonon characteristic lengths are broad in crystalline solids,
which makes nanowires insufficient to fully suppress heat transport.
Here, we employed SiāGe alloy as well as nanowire structures
to maximize the depletion of heat-carrying phonons. This results in
a thermal conductivity as low as ā¼1.2 W/m-K at 450 K, showing
a large thermoelectric figure-of-merit (ZT) of ā¼0.46 compared
with those of SiGe bulks and even ZT over 2 at 800 K theoretically.
All thermoelectric properties were āsimultaneouslyā
measured from the same nanowires to facilitate accurate ZT measurements.
The surface-boundary scattering is prominent when the nanowire diameter
is over ā¼100 nm, whereas alloying plays a more important role
in suppressing phonon transport for smaller ones