Abstract: Nanocomposite materials comprising a SiGe matrix with silicide and/or germanide nanoinclusions dispersed therein, said nanocomposite materials having improved thermoelectric energy conversion capacity.

Abstract: The present disclosure provides improved solid-state thermoelectric devices. A thermoelectric architecture referred to as a nanowire composite includes a plurality of intersecting semiconductor nanowires grown on metallic templates that are formed on a non-single crystal substrate. A plurality of nanowire composites form modules used in thermoelectric devices to generate electric power. The thermoelectric devices using these modules may be fabricated more cost effectively and perform better than conventional thermoelectric devices.

Abstract: Embodiments of the present invention are directed to nanowire-based systems for performing surface-enhanced Raman spectroscopy. In one embodiment, a system comprises a substrate having a surface and a plurality of tapered nanowires disposed on the surface. Each nanowire has a tapered end directed away from the surface. The system also includes a plurality of nanoparticles disposed near the tapered end of each nanowire. When each nanowire is illuminated with light of a pump wavelength, Raman excitation light is emitted from the tapered end of the nanowire to interact with the nanoparticles and produce enhanced Raman scattered light from molecules located in close proximity to the nanoparticles.

Abstract: Nanowire-based photovoltaic energy conversion devices and related fabrication methods therefor are described. A plurality of photovoltaic (PV) nanowires extend outwardly from a surface layer of a substrate, each PV nanowire having a root end near the substrate surface layer and a tip end opposite the root end. For some embodiments, a collar material is formed that laterally surrounds and is in contact with the PV nanowires along a portion of one or more of their ends. According to some embodiments, the PV nanowires are formed on a crystalline silicon substrate. According to some other embodiments, the PV nanowires are formed on a roll-sourced continuous substrate.

Abstract: Nanowire-based photovoltaic energy conversion devices and related fabrication methods therefor are described. A plurality of photovoltaic (PV) nanowires extend outwardly from a surface layer of a substrate, each PV nanowire having a root end near the substrate surface layer and a tip end opposite the root end. For one preferred embodiment, a canopy-style tip-side electrode layer contacts the tip ends of the PV nanowires and is separated from the substrate surface layer by an air gap layer, the PV nanowires being disposed within the air gap layer. For another preferred embodiment, a tip-side electrode layer is disposed upon a layer of optically transparent, electrically insulating solid filler material that laterally surrounds the PV nanowires along a portion of their lengths, wherein an air gap is disposed between the solid filler layer and the substrate surface layer. Methods for fabricating the nanowire-based photovoltaic energy conversion devices are also described.

Abstract: An optical emitter includes at least one nanowire connected in a circuit such that current selectively flows into the nanowire. The nanowire has a length-to-diameter ratio of ten or less. A method for generating optical emission includes applying a voltage across a nanowire to inject charge carriers into the nanowire, the nanowire having a length-to-diameter ratio of ten or less; and confining the charge carriers within the nanowire by placing a high bandgap material at each end of the nanowire, wherein the charge carriers recombine to emit optical energy.

Abstract: One embodiment in accordance with the invention is a solar cell comprising a non-single crystal substrate; a nanowire grown from a surface of the non-single crystal substrate; and an electrode coupled to the nanowire, wherein the nanowire is electrically conductive and is for absorbing electromagnetic wave and generating a current.

Abstract: A gain-clamped semiconductor optical amplifier comprises: at least one first surface; at least one second surface, each second surface facing and electrically isolated from a respective first surface; a plurality of nanowires connecting each opposing pair of the first and second surfaces in a bridging configuration; and a signal waveguide overlapping the nanowires such that an optical signal traveling along the signal waveguide is amplified by energy provided by electrical excitation of the nanowires.

Abstract: A nanowire-based photonic device and an array employ nanowires connecting between coaxially arranged electrodes in a non-uniform manner along a vertical extent of the electrodes. The device includes a pair of the electrodes separated by a circumferential gap. The nanowires chaotically emanate from an inner electrode of the pair and connect across the circumferential gap to an outer electrode of the pair. The array includes an outer electrode having an interconnected pattern of cells and inner electrodes, one per cell, arranged coaxially with and separated from the outer electrode by respective circumferential gaps. The nanowires chaotically emanate from the inner electrodes and connect across the respective circumferential gaps of the cells to the outer electrode. The device and the arrays further include a semiconductor junction between the electrodes.

Abstract: A gain-clamped semiconductor optical amplifier comprises: at least one first surface; at least one second surface, each second surface facing and electrically isolated from a respective first surface; a plurality of nanowires connecting each opposing pair of the first and second surfaces in a bridging configuration; and a signal waveguide overlapping the nanowires such that an optical signal traveling along the signal waveguide is amplified by energy provided by electrical excitation of the nanowires.

Abstract: A photonic device, a method of making the device and a nano-scale antireflector employ a bramble of nanowires. The photonic device and the method include a first layer of a microcrystalline material provided on a substrate surface and a second layer of a microcrystalline material provided on the substrate surface horizontally spaced from the first layer by a gap. The photonic device and the method further include, and the nano-scale antireflector includes, the bramble of nanowires formed between the first layer and the second layer. The nanowires have first ends integral to crystallites in each of the first layer and the second layer. The nanowires of the bramble extend into the gap from each of the first layer and the second layer.

Abstract: Nanowire-based opto-electronic devices including nanowire lasers, photodetectors and semiconductor optical amplifiers are disclosed. The devices include nanowires grown from single crystal and/or non-single surfaces. The semiconductor optical amplifiers include nanowire arrays that act as ballast lasers to amplify a signal carried by a signal waveguide. Embodiments of the nanowire lasers and photodetectors include horizontal and vertical nanowires that can provide different polarizations.

Abstract: A hetero-crystalline semiconductor device and a method of making the same include a non-single crystalline semiconductor layer and a nanostructure layer that comprises a single crystalline semiconductor nanostructure integral to a crystallite of the non-single crystalline semiconductor layer.

Abstract: Embodiments of the present invention are directed to nanowire-based systems for performing surface-enhanced Raman spectroscopy. In one embodiment, a system comprises a substrate (102) having a surface and a plurality of tapered nanowires (104) disposed on the surface. Each nanowire has a tapered end directed away from the surface. The system also includes a plurality of nanoparticles (110) disposed near the tapered end of each nanowire. When each nanowire is illuminated with light of a pump wavelength, Raman excitation light is emitted from the tapered end of the nanowire to interact with the nanoparticles and produce enhanced Raman scattered light from molecules located in close proximity to the nanoparticles.

Abstract: Embodiments of the present invention are directed to systems for performing surface-enhanced Raman spectroscopy. In one embodiment, a system (100, 400, 600, 800, 900, 950) for performing Raman spectroscopy comprises a substrate (102) substantially transparent to a range of wavelengths of electromagnetic radiation and a plurality of nanowires (104, 602) disposed on a surface of the substrate. The nanowires are substantially transparent to the range of wavelengths of electromagnetic radiation. The system includes a material disposed on each of the nanowires. The electromagnetic radiation is transmitted within the substrate, into the nanowires, and emitted from the ends of the nanowires to produce enhanced Raman scattered light from molecules located on or in proximity to the material.

Abstract: Nanowire-based opto-electronic devices including nanowire lasers, photodetectors and semiconductor optical amplifiers are disclosed. The devices include nanowires grown from single crystal and/or non-single surfaces. The semiconductor optical amplifiers include nanowire arrays that act as ballast lasers to amplify a signal carried by a signal waveguide. Embodiments of the nanowire lasers and photodetectors include horizontal and vertical nanowires that can provide different polarizations.

Abstract: Nanocomposite materials comprising a SiGe matrix with silicide and/or germanide nanoinclusions dispersed therein, said nanocomposite materials having improved thermoelectric energy conversion capacity.

Abstract: Methods of making nanometer-scale semiconductor structures with controlled size are disclosed. Semiconductor structures that include one or more nanowires are also disclosed. The nanowires can include a passivation layer or have a hollow tube structure.

Abstract: One embodiment in accordance with the invention is a solar cell comprising a non-single crystal substrate; a nanowire grown from a surface of the non-single crystal substrate; and an electrode coupled to the nanowire, wherein the nanowire is electrically conductive and is for absorbing electromagnetic wave and generating a current.

Abstract: A hetero-crystalline device structure and a method of making the same include a first layer and a nanostructure integral to a crystallite in the first layer. The first layer is a non-single crystalline material. The nanostructure is a single crystalline material. The nanostructure is grown on the first layer integral to the crystallite using epitaxial growth.