82 research outputs found
Germanium Nanorod Extinction Spectra: Discrete Dipole Approximation Calculations and Experiment
Optical extinction spectra were measured for dispersions
of germanium
(Ge) nanorods produced by arrested solution–liquid–solid
(SLS) growth using bismuth (Bi) seeds. Peaks in the real (<i>n</i>) and imaginary (<i>k</i>) parts of the complex
index of refraction of Ge give rise to an absorbance peak at ∼600
nm, which shifts to slightly longer wavelengths with increased aspect
ratio. Discrete dipole approximation calculations of absorption and
scattering cross sections reveal that the length-dependent optical
properties result from enhanced light trapping and absorption
Optical Properties of Silicon and Germanium Nanowire Fabric
The optical properties of free-standing nonwoven silicon
(Si) and
germanium (Ge) nanowire fabrics, including diffuse and specular reflectance,
diffuse and direct transmittance, and absorptance spectra, were measured
using an integrating sphere to account fully for all incident photons.
Very thin, 50 μm thick, sheets with ∼90% void volume
have extremely high optical densities. They are optically opaque across
nearly all wavelengths from ultraviolet to near-infrared, and only
minimal light penetrates when photon energies are below the band gap.
The high optical density arises from a combination of scattering and
absorption due to their high aspect ratio and narrow diameter as well
as surface effects due to their very high surface area to volume ratio
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Passive wireless self-resonant sensor
A sensor for detecting one or more materials includes a substrate, a passivation layer formed on the substrate, a self-resonant structure and a high surface area material disposed on the passivation layer. The self-resonant structure includes a planar spiral inductor and a plurality of planar interdigitated capacitor electrodes disposed within the passivation layer. The planar spiral inductor includes an electrically conductive trace formed on the substrate in a planar spiral pattern having at least two turns and an inter-winding space between parallel segments of the electrically conductive trace. The plurality of planar interdigitated capacitor electrodes are electrically connected to the electrically conductive trace of the planar spiral inductor and formed on the substrate within the inter-winding space of at least one outermost turn of the planar spiral inductor. The high surface area material includes a conformal polymer coating to increase a sensitivity to the one or more materials.Board of Regents, University of Texas Syste
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