Abstract: An electrode of a chemical cell includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, each conductive projection of the array of conductive projections having a semiconductor composition for reduction of carbon dioxide (CO2) in the chemical cell, and a catalyst arrangement disposed along each conductive projection of the array of conductive projections, the catalyst arrangement including a copper-based catalyst and an iron-based catalyst for the reduction of carbon dioxide (CO2) in the chemical cell.

Abstract: A method of fabricating a device includes providing a substrate of the device, forming a structure of the device, the structure being supported by the substrate, having a semiconductor composition, and including a surface, where nitrogen is present at the surface, and incorporating oxygen into the surface to form a stabilizing layer on the surface.

Abstract: An epitaxial growth process, referred to as metal-semiconductor junction assisted epitaxy, of ultrawide bandgap aluminum gallium nitride (AlGaN) is disclosed. The epitaxy of AlGaN is performed in metal-rich (e.g., Ga-rich) conditions using plasma-assisted molecular beam epitaxy. The excess Ga layer leads to the formation of a metal-semiconductor junction during the epitaxy of magnesium (Mg)-doped AlGaN, which pins the Fermi level away from the valence band at the growth front. The Fermi level position is decoupled from Mg-dopant incorporation; that is, the surface band bending allows the formation of a nearly n-type growth front despite p-type dopant incorporation. With controlled tuning of the Fermi level by an in-situ metal-semiconductor junction during epitaxy, efficient p-type conduction can be achieved for large bandgap AlGaN.

Abstract: An all-epitaxial, electrically injected surface-emitting green laser operates in a range of about 520-560 nanometers (nm). At 523 nm, for example, the device exhibits a threshold current density of approximately 0.4 kilo-amperes per square centimeter (kA/cm2), which is over one order of magnitude lower than that of previously reported blue laser diodes.

Abstract: An epitaxial growth process, referred to as metal-semiconductor junction assisted epitaxy, of ultrawide bandgap aluminum gallium nitride (AlGaN) is disclosed. The epitaxy of AlGaN is performed in metal-rich (e.g., Ga-rich) conditions using plasma-assisted molecular beam epitaxy. The excess Ga layer leads to the formation of a metal-semiconductor junction during the epitaxy of magnesium (Mg)-doped AlGaN, which pins the Fermi level away from the valence band at the growth front. The Fermi level position is decoupled from Mg-dopant incorporation; that is, the surface band bending allows the formation of a nearly n-type growth front despite p-type dopant incorporation. With controlled tuning of the Fermi level by an in-situ metal-semiconductor junction during epitaxy, efficient p-type conduction can be achieved for large bandgap AlGaN.

Abstract: A device includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, a plurality of catalyst nanoparticles disposed over the array of conductive projections, and an oxide layer covering the plurality of catalyst nanoparticles and the array of conductive projections. The oxide layer has a thickness on the order of a size of each catalyst nanoparticle of the plurality of catalyst nanoparticles.

Abstract: A nanowire can include a first semiconductor portion, a second portion including a quantum structure disposed on the first portion, and a second semiconductor portion disposed on the second portion opposite the first portion. The quantum structure can include one or more quantum core structures and a quantum core shell disposed about the one or more quantum core structures. The one or more quantum core structures can include one or more quantum disks, quantum arch-shaped forms, quantum wells, quantum dots within quantum wells or combinations thereof.

Abstract: GaN-based nanowire heterostructures have been intensively studied for applications in light emitting diodes (LEDs), lasers, solar cells and solar fuel devices. Surface charge properties play a dominant role on the device performance and have been addressed within the prior art by use of a relatively thick large bandgap AlGaN shell covering the surfaces of axial InGaN nanowire LED heterostructures has been explored and shown substantial promise in reducing surface recombination leading to improved carrier injection efficiency and output power. However, these lead to increased complexity in device design, growth and fabrication processes thereby reducing yield/performance and increasing costs for devices. Accordingly, there are taught self-organising InGaN/AlGaN core-shell quaternary nanowire heterostructures wherein the In-rich core and Al-rich shell spontaneously form during the growth process.

Abstract: An electrode for a reaction in a chemical cell includes a substrate having a surface, an array of nanostructures supported by the substrate and extending outward from the surface of the substrate, each nanostructure of the array of nanostructures having a semiconductor composition, and a catalyst arrangement disposed along each nanostructure of the array of nanostructures, the catalyst arrangement comprising a metal-based catalyst for the reaction in the chemical cell. The semiconductor composition of each nanostructure of the array of nanostructures establishes sites at which the metal-based catalyst is anchored to the nanostructure. The array of nanostructures and the catalyst arrangement are configured such that the metal-based catalyst is distributed along sidewalls of each nanostructure of the array of nanostructures at an atomic scale.

Abstract: InGaN/GaN quantum layer nanowire light emitting diodes are fabricated into a single cluster capable of exhibiting a wide spectral output range. The nanowires having InGaN/GaN quantum layers formed of quantum dots are tuned to different output wavelengths using different nanowire diameters, for example, to achieve a full spectral output range covering the entire visible spectrum for display applications. The entire cluster is formed using a monolithically integrated fabrication technique that employs a single-step selective area epitaxy growth.

Abstract: A nanowire can include a first semiconductor portion, a second portion including a quantum structure disposed on the first portion, and a second semiconductor portion disposed on the second portion opposite the first portion. The quantum structure can include one or more quantum core structures and a quantum core shell disposed about the one or more quantum core structures. The one or more quantum core structures can include one or more quantum disks, quantum arch-shaped forms, quantum wells, quantum dots within quantum wells or combinations thereof.

Abstract: Systems and methods presented herein include efficient and effective Light Emitting Devices (LED) devices. In one embodiment, a light emitting device comprises: a substrate comprising silicon; a first portion comprising a group III-V compound component with a first type of doping; a second portion comprising an active region, a shell comprising a gradient configuration with piezoelectric field compensation characteristics; and a third portion comprising a group III-V compound component with a second type of doping, The silicon substrate is coupled to the first portion. The first portion and shell are coupled to the second portion with is in turn coupled to the third portion. The active region comprises a quantum core structure with strain compensation barriers and polarization doping. The strain compensated barriers form multiple quantum wells. In one embodiment, the strain compensation barriers include AlGaN in a configuration that compensates tensile strain within the active region.

Abstract: A photocatalytic device includes a substrate having a surface, and an array of conductive projections supported by the substrate and extending outward from the surface of the substrate. Each conductive projection of the array of conductive projections has a semiconductor composition. The semiconductor composition establishes a photochemical diode. The surface may be nonplanar such that subsets of the array of conductive projections are oriented at different angles.

Abstract: A method of fabricating a semiconductor device includes providing a substrate, implementing a growth procedure to form a semiconductor layer supported by the substrate, performing an anneal of the semiconductor layer, the anneal being conducted at a higher temperature than the growth procedure, and repeating the growth procedure and the anneal. The anneal is conducted at or above a decomposition temperature for the semiconductor layer.

Abstract: Solid state sources offer potential advantages including high brightness, electricity savings, long lifetime, and higher color rendering capability, when compared to incandescent and fluorescent light sources. To date however, many of these advantages have not been borne out in providing white LED lamps for general lighting applications. The inventors have established that surface recombination through non-radiative processes results in highly inefficient electrical injection. Exploiting in-situ grown shells in combination with dot-in-a-wire LED structures to overcome this limitation through the effective lateral confinement offered by the shell, the inventors have demonstrated core-shell dot-in-a-wire LEDs with significantly improved electrical injection efficiency and output power, providing phosphor-free InGaN/GaN nanowire white LEDs operating with milliwatt output power and color rendering indices of 95-98.

Abstract: An electrode of a chemical cell includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, each conductive projection of the array of conductive projections having a semiconductor composition for reduction of carbon dioxide (CO2) in the chemical cell, and a catalyst arrangement disposed along each conductive projection of the array of conductive projections, the catalyst arrangement including a copper-based catalyst and an iron-based catalyst for the reduction of carbon dioxide (CO2) in the chemical cell.

Abstract: Nanowire light emitting diodes (LEDs) are operable for spontaneous emission of light at significantly reduced current densities and with very narrow linewidths relative to conventional LEDs.

Abstract: A method of fabricating a heterostructure includes providing a substrate, and implementing a non-sputtered, epitaxial growth procedure at a growth temperature to form a wurtzite structure supported by the substrate. The wurtzite structure includes an alloy of gallium nitride. The non-sputtered, epitaxial growth procedure is configured to incorporate a group IIIB element into the alloy. The wurtzite structure exhibits a breakdown field strength greater than a ferroelectric coercive field strength of the wurtzite structure.

Abstract: GaN-based nanowire heterostructures have been intensively studied for applications in light emitting diodes (LEDs), lasers, solar cells and solar fuel devices. Surface charge properties play a dominant role on the device performance and have been addressed within the prior art by use of a relatively thick large bandgap AlGaN shell covering the surfaces of axial InGaN nanowire LED heterostructures has been explored and shown substantial promise in reducing surface recombination leading to improved carrier injection efficiency and output power. However, these lead to increased complexity in device design, growth and fabrication processes thereby reducing yield/performance and increasing costs for devices. Accordingly, there are taught self-organising InGaN/AlGaN core-shell quaternary nanowire heterostructures wherein the In-rich core and Al-rich shell spontaneously form during the growth process.

Abstract: A device includes a substrate, and a plurality of structures supported by the substrate, each structure of the plurality of structures including a Group III-nitride base, first and second Group III-nitride charge carrier injection layers supported by the Group III-nitride base, and a quantum heterostmcture disposed between the first and second charge carrier injection layers. The quantum hetero structure includes a pair of Group III-nitride barrier layers, and a Group III-nitride active layer disposed between the pair of Group III-nitride barrier layers. The Group III-nitride active layer has a thickness for quantum confinement of charge carriers. At least one of the pair of Group III-nitride barrier layers has a nitride surface adjacent to the Group III-nitride active layer.