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: There is described a silicon photoanode generally having a silicon-based substrate; and a protective layer covering the silicon-base substrate, the protective layer having a transition metal dichalcogenide (TMDC) material, being uniform and having a thickness below about 8 nm.

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: 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: Important components of direct solar based nanowire enabled chemical processing and electrochemical systems are a high efficiency and highly stable photocathode and 2-photon dual electrodes. The former enables photo-excited electrons that lead to hydrogen generation whereas the later with complementary energy bandgap photoanode and photocathode enables high efficiency, unassisted solar-driven water splitting. Accordingly, it would be beneficial to leverage the high surface areas and self-contained conversion of direct solar illuminated hydrogen generation from such nanowires with multiple junctions for broad solar spectrum absorption by providing monolithically integrated multi-junction photocathodes. It would be further beneficial to provide nanowire based dual-photoelectrode systems that together with a parallel illumination scheme, can fundamentally address these critical challenges.

Abstract: Semiconductor light emitting diodes (LEDs) formed as (Al)GaN-based nanowire structures have a first semiconductor layer, a second semiconductor layer, and a thin metallic layer fabricated therebetween. The structures, operating in the deep ultraviolet (UV) spectral range, exhibit high photoluminescence efficiency at room temperature. The structures may be formed of an epitaxial metal tunnel junction operating as a reflector that enhances carrier transport to and from the semiconductor alloy layers, capable of producing external quantum efficiencies at least one order of magnitude higher than convention devices.

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-organizing InGaN/AlGaN core-shell quaternary nanowire heterostructures wherein the In-rich core and Al-rich shell spontaneously form during the growth process.

Abstract: A nanostructure optoelectronic device, in accordance with aspects of the present technology, can include a group-III element semiconductor with a first type of doping, one or more quantum structures including a dilute-Antimonide group-III-Nitride disposed on the first type of doped group-III element semiconductor, and a group-III element semiconductor with a second type of doping disposed on the dilute-Antimonide group-III-Nitride. The concentration of the Antimony (Sb) can be adjusted to vary the energy bandgap of the dilute-Antimonide group-III-Nitride between 3.4 and 2.

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: The present disclosure relates to a reversible hydrogen transfer process and storage system using visible light to photocatalytically generate hydrogen from compounds comprising saturated or partially saturated carbocyclic residue and catalytically hydrogenate compounds comprising at least one carbocyclic aromatic residue.

Abstract: Semiconductor light emitting diodes (LEDs) formed as (Al)GaN-based nanowire structures have a first semiconductor layer, a second semiconductor layer, and a thin metallic layer fabricated therebetween. The structures, operating in the deep ultraviolet (UV) spectral range, exhibit high photoluminescence efficiency at room temperature. The structures may be formed of an epitaxial metal tunnel junction operating as a reflector that enhances carrier transport to and from the semiconductor alloy layers, capable of producing external quantum efficiencies at least one order of magnitude higher than convention devices.

Abstract: InGaN offers a route to high efficiency overall water splitting under one-step photo-excitation. Further, the chemical stability of metal-nitrides supports their use as an alternative photocatalyst. However, the efficiency of overall water splitting using InGaN and other visible light responsive photocatalysts has remained extremely low despite prior art work addressing optical absorption through band gap engineering. Within this prior art the detrimental effects of unbalanced charge carrier extraction/collection on the efficiency of the four electron-hole water splitting reaction have remained largely unaddressed. To address this growth processes are presented that allow for controlled adjustment and establishment of the appropriate Fermi level and/or band bending in order to allow the photochemical water splitting to proceed at high rate and high efficiency. Beneficially, establishing such material surface charge properties also reduces photo-corrosion and instability under harsh photocatalysis conditions.

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: Important components of direct solar based nanowire enabled chemical processing and electrochemical systems are a high efficiency and highly stable photocathode and 2-photon dual electrodes. The former enables photo-excited electrons that lead to hydrogen generation whereas the later with complementary energy bandgap photoanode and photocathode enables high efficiency, unassisted solar-driven water splitting. Accordingly, it would be beneficial to leverage the high surface areas and self-contained conversion of direct solar illuminated hydrogen generation from such nanowires with multiple junctions for broad solar spectrum absorption by providing monolithically integrated multi-junction photocathodes. It would be further beneficial to provide nanowire based dual-photoelectrode systems that together with a parallel illumination scheme, can fundamentally address these critical challenges.

Abstract: Semiconductor micro- and nanotubes allow the incorporation of ordered structures such as quantum wells and quantum dots into them providing the potential for ultralow threshold micro- and nanoscale lasers for use in applications such as future ultrahigh-speed photonic systems as well as quantum information processing. According to the invention a means of manufacturing these with high reproducibility, low processing complexity, and at high densities is provided. Also provided is a means of releasing these micro- and nanotubes with low stress and a method of “pick-and-place” allowing micro- and nanotubes to be exploited in devices integrated on substrates that are either incompatible with the manufacturing technique or where the area of substrate required to manufacture them is detrimental to the cost or performance of the circuit.

Abstract: Solid state sources offers 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, however, 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: Amongst the candidates for very high efficiency electronics, solid state light sources, photovoltaics, and photoelectrochemical devices, and photobiological devices are those based upon metal-nitride nanowires. Enhanced nanowire performance typically require heterostructures, quantum dots, etc which requirement that these structures are grown with relatively few defects and in a controllable reproducible manner. Additionally flexibility according to the device design requires that the nanowire at the substrate may be either InN or GaN. Methods of growing relatively defect free nanowires and associated structures for group IIIA-nitrides are presented without the requirement for foreign metal catalysts, overcoming the non-uniform growth of prior art techniques and allowing self-organizing quantum dot, quantum well and quantum dot-in-a-dot structures to be formed.

Abstract: Amongst the candidates for very high efficiency electronics, solid state light sources, photovoltaics, and photoelectrochemical devices, and photobiological devices are those based upon metal-nitride nanowires. Enhanced nanowire performance typically require heterostructures, quantum dots, etc which requirement that these structures are grown with relatively few defects and in a controllable reproducible manner. Additionally flexibility according to the device design requires that the nanowire at the substrate may be either InN or GaN. Methods of growing relatively defect free nanowires and associated structures for group IIIA-nitrides are presented without the requirement for foreign metal catalysts, overcoming the non-uniform growth of prior art techniques and allowing self-organizing quantum dot, quantum well and quantum dot-in-a-dot structures to be formed.

Abstract: Metal-nitride nanowires are amongst the candidates for very high efficiency electronics, solid state light sources, photovoltaics, photoelectrochemical devices, and photobiological devices. Enhanced performance typically requires heterostructures, quantum dots, etc within structures that are grown with relatively few defects and in a controllable reproducible manner. Additionally device design flexibility requires that the nanowire at the substrate be either InN or GaN. Methods of growing relatively defect free nanowires and associated structures for group IIIA-nitrides are presented without foreign metal catalysts thereby overcoming the non-uniform growth of prior art techniques and allowing self-organizing quantum dot, quantum well and quantum dot-in-a-dot structures to be formed, thereby supporting variety of high efficiency devices.