5,211 research outputs found
Transmission of doughnut light through a bull's eye structure
We experimentally investigate the extraordinary optical transmission of
doughnut light through a bull's eye structure. Since the intensity is vanished
in the center of the beam, almost all the energy reaches the circular
corrugations (not on the hole), excite surface plasmons which propagate through
the hole and reradiate photons. The transmitted energy is about 57 times of the
input energy on the hole area. It is also interesting that the transmitted
light has a similar spatial shape with the input light although the diameter of
the hole is much smaller than the wavelength of light.Comment: 3 pages,4 figure
A New Two-Dimensional Functional Material with Desirable Bandgap and Ultrahigh Carrier Mobility
Two-dimensional (2D) semiconductors with direct and modest bandgap and
ultrahigh carrier mobility are highly desired functional materials for
nanoelectronic applications. Herein, we predict that monolayer CaP3 is a new 2D
functional material that possesses not only a direct bandgap of 1.15 eV (based
on HSE06 computation), and also a very high electron mobility up to 19930 cm2
V-1 s-1, comparable to that of monolayer phosphorene. More remarkably, contrary
to the bilayer phosphorene which possesses dramatically reduced carrier
mobility compared to its monolayer counterpart, CaP3 bilayer possesses even
higher electron mobility (22380 cm2 V-1 s-1) than its monolayer counterpart.
The bandgap of 2D CaP3 can be tuned over a wide range from 1.15 to 0.37 eV
(HSE06 values) through controlling the number of stacked CaP3 layers. Besides
novel electronic properties, 2D CaP3 also exhibits optical absorption over the
entire visible-light range. The combined novel electronic, charge mobility, and
optical properties render 2D CaP3 an exciting functional material for future
nanoelectronic and optoelectronic applications
Radiative thermal switch via metamaterials made of vanadium dioxide-coated nanoparticles
In this work, a thermal switch is proposed based on the phase-change material
vanadium dioxide (VO2) within the framework of near-field radiative heat
transfer (NFRHT). The radiative thermal switch consists of two metamaterials
filled with core-shell nanoparticles, with the shell made of VO2. Compared to
traditional VO2 slabs, the proposed switch exhibits a more than 2-times
increase in the switching ratio, reaching as high as 90.29% with a 100 nm
vacuum gap. The improved switching effect is attributed to the capability of
the VO2 shell to couple with the core, greatly enhancing heat transfer with the
insulating VO2, while blocking the motivation of the core in the metallic state
of VO2. As a result, this efficiently enlarges the difference in photonic
characteristics between the insulating and metallic states of the structure,
thereby improving the ability to rectify the NFRHT. The proposed switch opens
pathways for active control of NFRHT and holds practical significance for
developing thermal photon-based logic circuits
Investigation of ultra-thin Al₂O₃ film as Cu diffusion barrier on low-k (k=2.5) dielectrics
Ultrathin Al(2)O(3) films were deposited by PEALD as Cu diffusion barrier on low-k (k=2.5) material. The thermal stability and electrical properties of the Cu/low k system with Al(2)O(3) layers with different thickness were studied after annealing. The AES, TEM and EDX results revealed that the ultrathin Al(2)O(3) films are thermally stable and have excellent Cu diffusion barrier performance. The electrical measurements of dielectric breakdown and TDDB tests further confirmed that the ultrathin Al(2)O(3) film is a potential Cu diffusion barrier in the Cu/low-k interconnects system
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