Abstract: A photonic connection includes a first fiber and a second fiber. The first fiber has a core with a first predetermined pattern defined on or in a facet thereof, and the second fiber has a core with a second predetermined pattern defined on or in a facet thereof. The second predetermined pattern is complementary to the first predetermined pattern such that the first fiber or the second fiber fits into another of the second fiber or the first fiber at a single orientation and position.

Abstract: A semiconductor device which has controlled optical absorption includes a substrate, and a semiconductor layer supported by the substrate. The semiconductor has variable optical absorption at a predetermined optical frequency in relationship to a bandgap of the semiconductor layer. Also included is a strain application structure coupled to the semiconductor layer to create a strain in the semiconductor layer to change the semiconductor bandgap.

Abstract: A nanowire-based device includes the pair of isolated electrodes and a nanowire bridging between respective surfaces of the isolated electrodes of the pair. Specifically, the nanowire-based device having isolated electrodes comprises: a substrate electrode having a crystal orientation; a ledge electrode that is an epitaxial semiconductor having the crystal orientation of the substrate electrode; and a nanowire bridging between respective surfaces of the substrate electrode and the ledge electrode.

Abstract: Embodiments of the present invention are related to nanowire-based devices that can be configured and operated as modulators, chemical sensors, and light-detection devices. In one aspect, a nanowire-based device includes a reflective member, a resonant cavity surrounded by at least a portion of the reflective member, and at least one nanowire disposed within the resonant cavity. The nanowire includes at least one active segment selectively disposed along the length of the nanowire to substantially coincide with at least one antinode of light resonating within the cavity. The active segment can be configured to interact with the light resonating within the cavity.

Abstract: A technique is provided for forming a molecule or an array of molecules having a defined orientation relative to the substrate or for forming a mold for deposition of a material therein. The array of molecules is formed by dispersing them in an array of small, aligned holes (nanopores), or mold, in a substrate. Typically, the material in which the nanopores are formed is insulating. The underlying substrate may be either conducting or insulating. For electronic device applications, the substrate is, in general, electrically conducting and may be exposed at the bottom of the pores so that one end of the molecule in the nanopore makes electrical contact to the substrate. A substrate such as a single-crystal silicon wafer is especially convenient because many of the process steps to form the molecular array can use techniques well developed for semiconductor device and integrated-circuit fabrication.

Abstract: A radiation-emitting device includes a nanowire that is structurally and electrically coupled to a first electrode and a second electrode. The nanowire includes a double-heterostructure semiconductor device configured to emit electromagnetic radiation when a voltage is applied between the electrodes. A device includes a nanowire having an active longitudinal segment selectively disposed at a predetermined location within a resonant cavity that is configured to resonate at least one wavelength of electromagnetic radiation emitted by the segment within a range extending from about 300 nanometers to about 2,000 nanometers. Active nanoparticles are precisely positioned in resonant cavities by growing segments of nanowires at known growth rates for selected amounts of time.

Abstract: A sensing system includes a nanowire, a passivation layer established on at least a portion of the nanowire, and a barrier layer established on the passivation layer.

Abstract: A method of making a sensor comprises substantially laterally growing at least one nanowire having at least two segments between two electrodes, whereby a junction or connection is formed between the at least two segments; and establishing a sensing material adjacent to the junction or connection, and adjacent to at least a portion of each of the at least two segments, wherein the sensing material has at least two states.

Abstract: A method of making a crystalline semiconductor structure provides a photonic device by employing low thermal budget annealing process. The method includes annealing a non-single crystal semiconductor film formed on a substrate to form a polycrystalline layer that includes a transition region adjacent to a surface of the film and a relatively thicker columnar region between the transition region and the substrate. The transition region includes small grains with random grain boundaries. The columnar region includes relatively larger columnar grains with substantially parallel grain boundaries that are substantially perpendicular to the substrate. The method further includes etching the surface to expose the columnar region having an irregular serrated surface.

Abstract: A structure comprising a layer of graphene supported on a substrate wherein the substrate is pre-selected to have a coefficient of thermal expansion that is either matched within about 10% of that of graphene or mis-matched, thereby inducing controlled stress in the graphene layer to control electrical and/or mechanical properties of devices fabricated in the graphene layer.

Abstract: A sensing device includes an optical cavity having two substantially opposed reflective surfaces. At least one nanowire is operatively disposed in the optical cavity. A plurality of metal nanoparticles is established on the at least one nanowire.

Abstract: A process is provided for fabricating rounded three-dimensional germanium active channels for transistors and sensors. For forming sensors, the process comprises providing a crystalline silicon substrate; depositing an oxide mask on the crystalline silicon substrate; patterning the oxide mask with trenches to expose linear regions of the silicon substrate; epitaxially grow germanium selectively in the trenches, seeded from the silicon wafer; optionally etching the SiO2 mask partially, so that the cross section resembles a trapezoid on a stem; and annealing at an elevated temperature. The annealing process forms the rounded channel. For forming transistors, the process further comprises depositing and patterning a gate oxide and gate electrode onto this structure to form the gate stack of a MOSFET device; and after patterning the gate, implanting dopants into the source and drain located on the parts of the germanium cylinder on either side of the gate line.

Abstract: A photonic structure includes a plurality of annealed, substantially smooth-surfaced ellipsoids arranged in a matrix. Additionally, a method of producing a photonic structure is provided. The method includes providing a semiconductor material, providing an etch mask comprising a two-dimensional hole array, and disposing the etch mask on at least one surface of the semiconductor material. The semiconductor material is then etched through the hole array of the etch mask to produce holes in the semiconductor material and thereafter applying a passivation layer to surfaces of the holes. Additionally, the method includes repeating the etching and passivation-layer application to produce a photonic crystal structure that contains ellipsoids within the semiconductor material and annealing the photonic crystal structure to smooth the surfaces of the ellipsoids.

Abstract: Embodiments of the present invention are directed to nanowire (100) devices having concentric and coaxial doped regions and nanocrystals (108,110) disposed on the outer surfaces. In certain embodiments, the nanowire devices can include a light-emitting region (120) and be operated as a light-emitting diode (“LED”) (200), while in other embodiments, the nanowire devices can be operated as a light-detection device (600). The nanocrystals (108,110) disposed on the outer surfaces provide electron-conduction paths and include spaces that allow light to penetrate and be emitted from nanowire regions.

Abstract: A signal-amplification device for surface enhanced Raman spectroscopy (SERS). The signal-amplification device includes a non-SERS-active (NSA) substrate, a plurality of multi-tiered non-SERS-active nanowire (MNSANW) structures and a plurality of metallic SERS-active nanoparticles. In addition, a MNSANW structure of the plurality of MNSANW structures includes a main arm of a plurality of main arms and a plurality of arms of at least secondary order. The plurality of main arms is disposed on the NSA substrate; and, a secondary arm of the plurality of arms is disposed on the main arm. Moreover, a metallic SERS-active nanoparticle of the plurality of metallic SERS-active nanoparticles is disposed on a surface of the MNSANW structure.

Abstract: A method for controlling catalyst nanoparticle positioning includes establishing a mask layer on a post such that a portion of a vertical surface of the post remains exposed. The method further includes establishing a catalyst nanoparticle material on the mask layer and directly adjacent at least a portion of the exposed portion of the vertical surface.

Abstract: Semiconductor structures are disclosed including a substrate comprising a semiconductor material and having opposed first and second surfaces, and at least one conductive via extending from the first surface to the second surface. The conductive vias can extend at angles relative to the first surface, such as acute angles or 90°. The conductive vias can include segments that extend at different angles. Methods of forming conductive vias in semiconductor structures are provided. In the methods, a thermal gradient is applied in combination with an electric field to form conductive vias.

Abstract: Various aspects of the present invention are directed to optical structures including selectively positioned color centers, methods of fabricating such optical structures, and photonic chips that utilize such optical structures. In one aspect of the present invention, an optical structure includes an optical medium having a number of strain-localization regions. A number of color centers are distributed within the optical medium in a generally selected pattern, with at least a portion of the strain-localization regions including one or more of the color centers. In another aspect of the present invention, a method of positioning color centers in an optical medium is disclosed. In the method, a number of strain-localization regions are generated in the optical medium. The optical medium is annealed to promote diffusion of at least a portion of the color centers to the strain-localization regions.

Abstract: A device configured to have a nanowire formed laterally between two electrodes includes a substrate and an insulator layer established on at least a portion of the substrate. An electrode of a first conductivity type and an electrode of a second conductivity type different than the first conductivity type are established at least on the insulator layer. The electrodes are electrically isolated from each other. The electrode of the first conductivity type has a vertical sidewall that faces a vertical sidewall of the electrode of the second conductivity type, whereby a gap is located between the two vertical sidewalls. Methods are also disclosed for forming the device.

Abstract: A micro-ring configured to selectively detect or modulate optical energy includes at least one annular optical cavity; at least two electrodes disposed about the optical cavity configured to generate an electrical field in the at least one optical cavity; and an optically active layer optically coupled to the at least one optical cavity. A method of manipulating optical energy within a waveguide includes optically coupling at least one annular optical cavity with the waveguide; and selectively controlling an electrical field in the at least one annular optical cavity to modulate optical energy from the waveguide.