Abstract: Various embodiments of the present invention are directed to surface-plasmon-enhanced electromagnetic-radiation-emitting devices and to methods of fabricating these devices. In one embodiment of the present invention, an electromagnetic-radiation-emitting device comprises a multilayer core, a metallic device layer, and a substrate. The multilayer core has an inner layer and an outer layer, wherein the outer layer is configured to surround at least a portion of the inner layer. The metallic device layer is configured to surround at least a portion of the outer layer. The substrate has a bottom conducting layer in electrical communication with the inner layer and a top conducting layer in electrical communication with the metallic device layer such that the exposed portion emits surface-plasmon-enhanced electromagnetic radiation when an appropriate voltage is applied between the bottom conducting layer and the top conducting layer.

Abstract: Methods of fabricating a suspended mono-crystalline structure use annealing to induce surface migration and cause a surface transformation to produce the suspended mono-crystalline structure above a cavity from a heteroepitaxial layer provided on a crystalline substrate. The methods include forming a three dimensional (3-D) structure in the heteroepitaxial layer where the 3-D structure includes high aspect ratio elements. The 3-D structure is annealed at a temperature below a melting point of the heteroepitaxial layer. The suspended mono-crystalline structure may be a portion of a semiconductor-on-nothing (SON) substrate.

Abstract: An optical modulator and related methods are described. In accordance with one embodiment, the optical modulator comprises a waveguide for guiding an optical signal, and further comprises a ring resonator disposed in evanescent communication with the waveguide for at least one predetermined wavelength of the optical signal. The optical modulator further comprises a semiconductor pnpn junction structure that is at least partially coextensive with at least a portion of a resonant light path of the ring resonator. The optical modulator is configured such that the semiconductor pnpn junction structure receives an electrical control signal thereacross. The electrical control signal controls a free carrier population in the resonant light path where coextensive with the pnpn junction structure. A resonance condition of the ring resonator at the predetermined wavelength is thereby controlled by the electrical control signal, and the optical signal is thereby modulated according to the electrical control signal.

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.

Abstract: A deformable optical element includes an elastically deformable lens. Electrical contacts are directly attached to the elastically deformable lens and configured to receive an applied voltage. The electrical contacts have opposing surfaces configured to develop electrostatic forces in response to the applied voltage. The electrostatic forces deform the elastically deformable lens to create a predetermined optical effect.

Abstract: A multilayer device includes an electronic device layer, a first electrode associated with the electronic device layer, an optical layer, a second electrode associated with the optical layer, and an insulator layer provided between the first and second electrodes. The first and second electrodes are capacitively coupled to each other to facilitate electrical communication between the electronic device layer and the optical layer through transmission of an electrical signal between the first and second electrodes. The electrical signal may be transmitted through the insulator layer. In addition, the electronic device layer and the optical layer may be in electrical communication with each other through capacitive coupling of the first electrode and the second electrode.

Abstract: An optical device includes a primary nanowire having a predetermined characteristic that affects an optical property of the primary nanowire. At least one secondary nanowire abuts the primary nanowire at a non-zero angle. The secondary nanowire(s) have another predetermined characteristic that affects an optical property of the secondary nanowire(s). A junction is formed between the primary and secondary nanowires. The device is configured to cause a portion of a light beam of a predetermined wavelength or range of wavelengths traveling through one of the primary nanowire or the secondary nanowire(s) to enter another of the secondary nanowire(s) or the primary nanowire.

Abstract: An optical device includes at least two materials forming a structure with a graded bandgap where photocarriers are generated. A first of the at least two materials has a larger concentration at opposed ends of the graded bandgap structure than a concentration of the first of the at least two materials at an interior region of the graded bandgap structure. The second of the at least two materials has a larger concentration at the interior region of the graded bandgap structure than the concentration of the second of the at least two materials at the opposed ends of the graded bandgap structure.

Abstract: Various aspects of the present invention are directed to a nanowire configured to couple electromagnetic radiation to a selected guided wave and devices incorporating such nanowires. In one aspect of the present invention, a nanowire structure includes a substrate and at least one nanowire attached to the substrate. A diameter, composition, or both may vary generally periodically along a length of the at least one nanowire. A coating may cover at least part of a circumferential surface of the at least one nanowire. The nanowire structure may be incorporated in a device including at least one optical-to-electrical converter operable to convert a guided wave propagating along the length of the at least one nanowire, at least in part responsive to irradiation, to an electrical signal. Other aspects of the present invention are directed to methods of fabricating nanowires structured to support guided waves.

Abstract: A method of positioning a catalyst nanoparticle that facilitates nanowire growth for nanowire-based device fabrication employs a structure having a vertical sidewall formed on a substrate. The methods include forming the structure, forming a targeted region in a surface of either the structure or the substrate, and forming a catalyst nanoparticle in the targeted region using one of a variety of techniques. The techniques control the position of the catalyst nanoparticle for subsequent nanowire growth. A resonant sensor system includes a nanowire-based resonant sensor and means for accessing the nanowire. The sensor includes an electrode and a nanowire resonator. The electrode is electrically isolated from the substrate. One or more of the substrate is electrically conductive, the nanowire resonator is electrically conductive, and the sensor further comprises another electrode. The nanowire resonator responds to an environmental change by displaying a change in oscillatory behavior.

Abstract: A method of forming an assembly of isolated nanowires of at least one material within a matrix of another material is provided. The method comprises: providing a substrate; forming a catalyst array on a major surface of the substrate; growing an array of the nanowires corresponding with the catalyst array, the nanowires, each comprising at least one material; and forming a matrix of another material that fills in spaces between the nanowires. The method is useful for producing a variety of structures useful in a number of devices, such as photonic bandgap structures and quantum dot structures.

Abstract: Various embodiments of the present invention relate generally to systems for performing Raman spectroscopy. In one embodiment, a system for performing Raman spectroscopy comprises an analyte holder having a surface configured to retain an analyte and a light concentrator configured to receive an incident beam of light, split the incident beam into one or more beams, and direct the one or more beams to substantially intersect at the surface. The system may also include a collector configured to focus each of the one or more beams onto the surface, collect the Raman scattered light emitted from the analyte, and direct the Raman scattered light away from the surface.

Abstract: A hybrid-scale electronic circuit, an internal electrical connection and a method of electrically interconnecting employ an interconnect having a tapered shape to electrically connect between different-scale circuits. The interconnect has a first end with an end dimension that is larger than an end dimension of an opposite, second end of the interconnect. The larger first end of the interconnect connects to an electrical contact of a micro-scale circuit and the second end of the interconnect connects to an electrical contact of a nano-scale circuit.

Abstract: A method for making a multi-level nanowire structure includes establishing a first plurality of nanowires on a substrate surface, wherein at least some of the nanowires are i) aligned at a predetermined crystallographically defined angle with respect to the substrate surface, ii) aligned substantially perpendicular with respect to the substrate surface, or iii) combinations of i and ii. An insulating layer is established between the nanowires of the first plurality such that one of two opposed ends of at least some of the nanowires positioned i) at the predetermined crystallographically defined angle, ii) substantially perpendicular with respect to the substrate surface, or iii) combinations of i and ii is exposed. Regions are grown from each of the exposed ends, and such regions coalesce to form a substantially continuous layer on the insulating layer. A second plurality of nanowires is established on the substantially continuous layer.

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 method for forming a graphene layer is disclosed herein. The method includes establishing an insulating layer on a substrate such that at least one seed region, which exposes a surface of the substrate, is formed. A seed material in the seed region is exposed to a carbon-containing precursor gas, thereby initiating nucleation of the graphene layer on the seed material and enabling lateral growth of the graphene layer along at least a portion of a surface of the insulating layer.

Abstract: A metal is deposited onto a surface electrochemically using a deposition solution including a metal salt. In making a composite nanostructure, the solution further includes an enhancer that promotes electrochemical deposition of the metal on the nanostructure. In a method of forming catalyzing nanoparticles, the metal preferentially deposits on a selected location of a surface that is exposed through a mask layer instead of on unexposed surfaces. A composite nanostructure apparatus includes an array of nanowires and the metal deposited on at least some nanowire surfaces. Some of the nanowires are heterogeneous, branched and include different adjacent axial segments with controlled axial lengths. In some deposition solutions, the enhancer one or both of controls oxide formation on the surface and causes metal nanocrystal formation. The deposition solution further includes a solvent that carries the metal salt and the enhancer.

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: An apparatus for thermal control includes a first component; a second component; an adjustable thermal link disposed between the first component and the second component; and a controller for selectively varying a thermal conductance of the adjustable thermal link. A method of controlling a temperature includes sensing a temperature of a first component; and adjusting a thermal conductance of an adjustable thermal link, the adjustable thermal link forming a thermal path between the first component and a second component; the thermal conductance of the adjustable thermal link being adjusted such that the temperature of the first component is controlled.

Abstract: One embodiment of the present invention relates to a light-emitting diode having one or more light-emitting layers, a pair of electrodes disposed on the light-emitting diode so that an operating voltage can be applied to generate light from the one or more light-emitting layers, and at least one external electrode in electronic communication with the one or more light-emitting layers. Applying an appropriate voltage to the at least one external electrodes at about the time the operating voltage is terminated extracts excess electrons from the one or more light-emitting layers and reduces the duration of electron-hole recombination during the time period over which the operating voltage is turned off.