6,928 research outputs found
Nanoarray-Enhanced Micromechanical Pressure Sensor with Remote Optical Readout
We demonstrate a compact implantable intraocular pressure (IOP) sensor with remote optical readout for glaucoma research and patient management. Using non-invasive white light, we excite the sensor’s pressure-sensitive optomechanical cavity and detect the reflected light, whose optical signature changes as a function of IOP. The sensor has provided robust measurements of hydrostatic pressure between 10-60 mmHg with an accuracy of 0.15 mmHg
Structural variations of Si 1-xC x and their light absorption controllability
The emergence of third-generation photovoltaics based on Si relies on tunable bandgap materials with embedded nanocrystalline Si. One of the most promising approaches is based on the mixed-phase Si1 -aEuro parts per thousand x C (x) . We have investigated the light absorption controllability of nanocrystalline Si-embedded Si1 -aEuro parts per thousand x C (x) produced by thermal annealing of the Si-rich Si1 -aEuro parts per thousand x C (x) and composition-modulated superlattice structure. In addition, stoichiometric SiC was also investigated to comparatively analyze the characteristic differences. As a result, it was found that stoichiometric changes of the matrix material and incorporation of oxygen play key roles in light absorption controllability. Based on the results of this work and literature, a design strategy of nanocrystalline Si-embedded absorber materials for third-generation photovoltaics is discussed.open3
Distance Dependence of the Energy Transfer Rate From a Single Semiconductor Nanostructure to Graphene
The near-field Coulomb interaction between a nano-emitter and a graphene
monolayer results in strong F\"orster-type resonant energy transfer and
subsequent fluorescence quenching. Here, we investigate the distance dependence
of the energy transfer rate from individual, i) zero-dimensional CdSe/CdS
nanocrystals and ii) two-dimensional CdSe/CdS/ZnS nanoplatelets to a graphene
monolayer. For increasing distances , the energy transfer rate from
individual nanocrystals to graphene decays as . In contrast, the
distance dependence of the energy transfer rate from a two-dimensional
nanoplatelet to graphene deviates from a simple power law, but is well
described by a theoretical model, which considers a thermal distribution of
free excitons in a two-dimensional quantum well. Our results show that accurate
distance measurements can be performed at the single particle level using
graphene-based molecular rulers and that energy transfer allows probing
dimensionality effects at the nanoscale.Comment: Main text (+ 5 figures) and Supporting Information (+ 7 figures
Controllable modification of transport properties of single-walled carbon nanotube field effect transistors with in situ Al decoration
We use an in situ Al decoration technique to control the transport characteristics of single-walled carbon nanotube field effect transistors (SWNT-FETs). Al nanoparticle decoration in a high vacuum caused the devices to change from p -type to n -type FETs, and subsequent exposure to the ambient atmosphere induced a gradual recovery of p -type character. In comparison with the bare SWNT-FETs under high vacuum, the channel-open devices with decorated Al particles exhibited reduced current under ambient conditions. However, selective Al decoration only at the contact resulted in an improved p -type current in ambient air.open182
Carbon nanotube diode fabricated by contact engineering with self-assembled molecules
The authors report the construction of carbon nanotube Schottky diodes by covering a selectively exposed area of the electrode with self-assembling molecules. Two self-assembling molecules with different polarities, 2-aminoethanethiol and 3-mercaptopropionic acid, were used to modify the Fermi level lineup at the selected contact. The devices showed p -type behavior with symmetric I-V showing clear rectifying behavior after treatment of one contact with 2-aminoethanethiol. Their experiment, in conjunction with the results of ab initio electronic structure calculations, suggests that the diode action stems from the asymmetric Fermi level lineup between the bare and engineered contacts.open131
Molecular Line Observations of the Small Protostellar Group L1251B
We present molecular line observations of L1251B, a small group of pre- and
protostellar objects, and its immediate environment in the dense C18O core
L1251E. These data are complementary to near-infrared, submillimeter and
millimeter continuum observations reported by Lee et al. (2006, ApJ, 648, 491;
Paper I). The single-dish data of L1251B described here show very complex
kinematics including infall, rotation and outflow motions, and the
interferometer data reveal these in greater detail. Interferometer data of N2H+
1-0 suggest a very rapidly rotating flattened envelope between two young
stellar objects, IRS1 and IRS2. Also, interferometer data of CO 2-1 resolve the
outflow associated with L1251B seen in single-dish maps into a few narrow and
compact components. Furthermore, the high resolution data support recent
theoretical studies of molecular depletions and enhancements that accompany the
formation of protostars within dense cores. Beyond L1251B, single-dish data are
also presented of a dense core located ~150" to the east that, in Paper I, was
detected at 850 micron but has no associated point sources at near- and
mid-infrared wavelengths. The relative brightness between molecules, which have
different chemical timescales, suggests it is less chemically evolved than
L1251B. This core may be a site for future star formation, however, since line
profiles of HCO+, CS, and HCN show asymmetry with a stronger blue peak, which
is interpreted as an infall signature.Comment: 46 pages, 18 figures. Accepted for publication in Ap
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Multifunctional-high resolution imaging plate based on hydrophilic graphene for digital pathology
In the present study, we showed that hydrophilic graphene can serve as an ideal imaging plate for biological specimens. Graphene being a single-atom-thick semi-metal with low secondary electron emission, array tomography analysis of serial sections of biological specimens on a graphene substrate showed excellent image quality with improved z-axis resolution, without including any conductive surface coatings. However, the hydrophobic nature of graphene makes the placement of biological specimens difficult; graphene functionalized with polydimethylsiloxane oligomer was fabricated using a simple soft lithography technique and then processed with oxygen plasma to provide hydrophilic graphene with minimal damage to graphene. High-quality scanning electron microscopy images of biological specimens free from charging effects or distortion were obtained, and the optical transparency of graphene enabled fluorescence imaging of the specimen; high-resolution correlated electron and light microscopy analysis of the specimen became possible with the hydrophilic graphene plate
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