Search

The present theoretical model deals with the transmission property of the Dirac fermions in the Floquet sidebands for the laser radiated graphene nanostructure. The laser assisted structure behaves as a tunneling barrier that leads to asymmetric transmission around the normal to the interface and is capable to confine the massless Dirac particles in a monolayer graphene strip. The absence of the Klein tunneling and the presence of a large number of controlling parameters would make the time dependent vector potential barrier superior over the electrostatic and magnetic barriers towards the opto-electronic device fabrication. [ABSTRACT FROM AUTHOR]

A metallic photonic crystal consisting of a triangular lattice of holes in a silicon layer coated with gold is fabricated at a lattice pitch of 3.75 μm using conventional lithographic methods. The photonic crystal exhibits a deep reflection minimum and sharp thermal emission peak near the lattice spacing. Scattering matrix simulations agree well with measurements. This simple structure with a single patterned metallic layer has no emission sidebands and can be scaled to other lattice spacings to tune the wavelength of the absorption and emission peak. [ABSTRACT FROM AUTHOR]

We develop and demonstrate the concept of impedance for a photonic crystal by generalizing the transverse wave impedance of conventional waveguides. The impedance involves a ratio of transverse fields and power flux. The calculated impedance for a two-dimensional photonic crystal is very well defined using the transfer matrix method. The predicted frequency-dependent reflectance from this impedance agrees very well with rigorous transfer matrix calculations for band modes and waveguiding modes in the band gap. This impedance concept will be very powerful in minimization of insertion loss into photonic crystal waveguides, designing waveguide splitters, and for modeling reflectance/transmittance from photonic crystals. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have experimentally and theoretically developed a unique thermally stimulated midinfrared source that emits radiation within a narrow range of wavelengths (δλ/λ≤0.2). The emission wavelengths are defined by the periodicity of a metal coated silicon-air photonic crystal etched into the emitter surface. The lattice of the holes in the metal mediate the coupling of light into discrete surface plasmon states. This yields surfaces with spectrally nonuniform infrared reflection properties where over much of the IR 90+% of photons are reflected yet, in a narrow spectral region, 90% absorption is observed. Transfer matrix calculations simulate well the position and strength of the absorption features. This technology will afford tunable infrared emitters with high power in a narrow spectral band that are critical for sensing, spectroscopy, and thermophotovoltaic applications. [ABSTRACT FROM AUTHOR]

With an aim to understanding the fundamental mechanisms underlying chemical mechanical planarization (CMP) of copper, we simulate the nanoscale polishing of a copper surface with molecular dynamics utilizing the embedded atom method. Mechanical abrasion produces rough planarized surfaces with a large chip in front of the abrasive particle, and dislocations in the bulk of the crystal. The addition of chemical dissolution leads to very smooth planarized copper surfaces and considerably smaller frictional forces that prevent the formation of bulk dislocations. This is a first step towards understanding the interplay between mechanistic material abrasion and chemical dissolution in chemical mechanical planarization of copper interconnects. [ABSTRACT FROM AUTHOR]

Examines the bond-length disorder and metastability in hydrogenated amorphous silicon. Relationship between temperature and relaxation time; Determination of hydrogen state distribution by fundamental bond length variation of the amorphous network; Description of defects formation.

Examines a perfectly reflecting substrate for planar dipole antennas in the 12-15 GHz regime using photonic band gap crystals. Optimization of the position, orientation and driving frequency of the dipole antenna in the photonic band gap crystals surface; Effect of the photonic crystals radiated power; Fabrication of the antenna on a photonic band gap crystal.

Tight-binding molecular dynamics has been used to simulate vibrationally excited Si–H and Si–D modes. Simulations find that vibrationally excited Si–D bending modes decay much more rapidly than Si–H bending modes, resulting in SiD bonds having much higher stability than SiH bonds. This provides a viable mechanism for reduced degradation in deuterated metal–oxide–semiconductor transistors and deuterated amorphous silicon devices. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Light-induced metastable defects in a-Si:H are proposed to be silicon dangling bonds accompanied by pairs of hydrogen atoms breaking a silicon bond, forming a complex with two Si-H bonds. This supports the model of Branz. These defects are the analog of the H[sub 2][sup *] defect in c-Si and their energy correlates with the bond-angle strain. Several features of the annealing are well described by this defect complex. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]