Abstract: A nanoscale apparatus (100) includes a nanoshell (110) extending from a substrate (102) and an epitaxial connection (120) between the substrate and an end (112) of the nanoshell adjacent to the substrate. A nanoscale sensor (200) includes surfaces (204, 206) extending relatively perpendicular to each other, a nanoshell (210) extending from one of the surfaces, and a detector (220) that monitors motion of the nanoshell relative to another of the surfaces spaced from the nanoshell by a gap (208). A method (300) of making a nanoscale apparatus includes growing (310) a nanowire on a surface; forming (320) a core-shell composite nanostructure; exposing (330) an end of the nanowire opposite to the surface with a FIB; and removing (340) the nanowire core from the exposed end, such that a nanoshell having a hollow region is attached to the surface. A material of the nanoshell (110, 210) excludes sp2-bonded carbon materials.

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: A nanowire device includes a nanowire 40 having differently functionalized segments 50, 51. Each of the segments 50, 51 is configured to interact with a species A, B to modulate the conductance of a segment 50, 51. The nanowire 40 is grown from a single catalyst 401 and the segments 50, 51 include a first segment 50 at a non-linear angle from a second segment 51.

Abstract: An optical device includes a first electrode of a first conductivity type, and a second electrode of a second conductivity type. A nanowire is positioned between the first and second electrodes. The nanowire has at least two segments and a junction region formed between the at least two segments. One of the segments is the first conductivity type and the other of the segments is the second conductivity type. At least one of the at least two segments has a predetermined characteristic that affects optical behavior of the junction region.

Abstract: A nanowire-based device and method employ removal of residual carriers. The nanowire-based device includes a semiconductor nanowire having a semiconductor junction, and a residual carrier sink. The residual carrier sink is located at or adjacent to the semiconductor nanowire near the semiconductor junction and employs one or both of enhanced recombination and direct extraction of the residual carriers. The method includes providing a semiconductor nanowire, forming a semiconductor junction within the semiconductor nanowire, forming a residual carrier sink, and removing residual carriers from the semiconductor junction region using the residual carrier sink.

Abstract: A nanowire sensor includes a first electrode, a second electrode, and a sensing element connecting the first electrode and the second electrode. The sensing element includes at least one nanowire connecting the first electrode and the second electrode and an electrically conductive film covering the at least one nanowire and extending between and contacting the first electrode and the second electrode, wherein conductance of the electrically conductive film is configured to change in the presence of at least one species to enable detection of the at least one species.

Abstract: A photonic device (200) and method (100) of making the photonic device (200) employs preferential etching of grain boundaries of a polycrystalline semiconductor material layer (210). The method (100) includes growing (110) the polycrystalline layer (210) on a substrate (201). The polycrystalline layer includes a transition region (212) of variously oriented grains and a region (214) of columnar grain boundaries (215) adjacent to the transition region. The method further includes preferentially etching (120) the colunmar grain boundaries to provide tapered structures (220) of the semiconductor material that are continuous (217) with respective aligned grains (213) of the transition region. The tapered structures are predominantly single crystal. The method further includes forming (140) a conformal semiconductor junction (240) on the tapered structures and providing (160) first and second electrodes.

Abstract: A thermoelectric device having a variable cross-section connecting structure includes a first electrode, a second electrode, and a connecting structure connecting the first electrode and the second electrode. The connecting structure has a first section and a second section. The width of the second section is greater than the width of the first section, and the width of the first section is less than a width that is approximately equivalent to a phonon mean free path through the first section.

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 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: 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.

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 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: Various embodiments of the present invention are directed to methods for coupling semiconductor-based photonic devices to diamond. In one embodiment of the present invention, a photonic device is optically coupled with a diamond structure. The photonic device comprises a semiconductor material and is optically coupled with the diamond structure with an adhesive substance that adheres the photonic device to the diamond structure. A method for coupling the photonic device with the diamond structure is also provided. The method comprises: depositing a semiconductor material on the diamond structure; forming the photonic device in the semiconductor material so that the photonic device couples with the diamond structure; and adhering the photonic device to the diamond structure.

Abstract: A device disclosed herein includes a first layer, a second layer, and a first plurality of nanowires established between the first layer and the second layer. The first plurality of nanowires is formed of a first semiconductor material. The device further includes a third layer, and a second plurality of nanowires established between the second and third layers. The second plurality of nanowires is formed of a second semiconductor material having a bandgap that is the same as or different from a bandgap of the first semiconductor material.

Abstract: A configurable memristive device (300) for regulating an electrical signal includes a memristive matrix (350) containing a first dopant species; emitter (320), collector (310), and a base electrodes (330, 340) which are in contact with the memristive matrix (350); and a mobile dopant species contained within a central region (360) contiguous with the base electrodes (330, 340), the mobile dopant species moving within the memristive matrix (350) in response to a programming electrical field. A method of configuring and using a memristive device (300) includes: applying a programming electrical field across a memristive matrix (350) such that a mobile dopant species creates a central doped region (360) which bisects the memristive matrix (350); and applying a control voltage to the central doped region (360) to regulate current flow between an emitter electrode (320) and a collector electrode (310).

Abstract: Multilayer carbon nanotube capacitors, and methods and printable compositions for manufacturing multilayer carbon nanotubes (CNTs) are disclosed. A first capacitor embodiment comprises: a first conductor; a plurality of fixed CNTs in an ionic liquid, each fixed CNT comprising a magnetic catalyst nanoparticle coupled to a carbon nanotube and further coupled to the first conductor; and a first plurality of free CNTs dispersed and moveable in the ionic liquid. Another capacitor embodiment comprises: a first conductor; a conductive nanomesh coupled to the first conductor; a first plurality of fixed CNTs in an ionic liquid and further coupled to the conductive nanomesh; and a plurality of free CNTs dispersed and moveable in the ionic liquid. Various methods of printing the CNTs and other structures, and methods of aligning and moving the CNTs using applied electric and magnetic fields, are also disclosed.

Abstract: Multilayer carbon nanotube capacitors, and methods and printable compositions for manufacturing multilayer carbon nanotubes (CNTs) are disclosed. A first capacitor embodiment comprises: a first conductor; a plurality of fixed CNTs in an ionic liquid, each fixed CNT comprising a magnetic catalyst nanoparticle coupled to a carbon nanotube and further coupled to the first conductor; and a first plurality of free CNTs dispersed and moveable in the ionic liquid. Another capacitor embodiment comprises: a first conductor; a conductive nanomesh coupled to the first conductor; a first plurality of fixed CNTs in an ionic liquid and further coupled to the conductive nanomesh; and a plurality of free CNTs dispersed and moveable in the ionic liquid. Various methods of printing the CNTs and other structures, and methods of aligning and moving the CNTs using applied electric and magnetic fields, are also disclosed.

Abstract: A fast injection optical switch is disclosed. The optical switch includes a thyristor having a plurality of layers including an outer doped layer and a switching layer. An area of the thyristor is configured to receive a light beam to be directed through at least one of the plurality of layers and exit the thyristor at a predetermined angle. At least two electrodes are coupled to the thyristor and configured to enable a voltage to be applied to facilitate carriers from the outer doped layer to be directed to the switching layer. Sufficient carriers can be directed to the switching layer to provide a change in refractive index of the switching layer to redirect at least a portion of the light beam to exit the thyristor at a deflection angle different from the predetermined angle.

Abstract: An electrically actuated device includes a first electrode, a second electrode, and an active region disposed between the first and second electrodes. At least two dopants are present in a spatially varying region of the active region prior to device actuation. The at least two dopants have opposite conductivity types and different mobilities.