Abstract: A solution for fabricating a semiconductor structure is provided. The semiconductor structure includes a plurality of semiconductor layers grown over a substrate using a set of epitaxial growth periods. During each epitaxial growth period, a first semiconductor layer having one of: a tensile stress or a compressive stress is grown followed by growth of a second semiconductor layer having the other of: the tensile stress or the compressive stress directly on the first semiconductor layer.

Abstract: Ultraviolet radiation is directed within an area. The target wavelength ranges and/or target intensity ranges of the ultraviolet radiation sources can correspond to at least one of a plurality of selectable operating configurations including a virus destruction operating configuration and a bacteria disinfection operating configuration. Each configuration can include a unique combination of the target wavelength range and target intensity range.

Abstract: A semiconductor structure, such as a group III nitride-based semiconductor structure is provided. The semiconductor structure includes a cavity containing semiconductor layer. The cavity containing semiconductor layer can have a thickness greater than two monolayers and a multiple cavities. The cavities can have a characteristic size of at least one nanometer and a characteristic separation of at least five nanometers.

Abstract: A semiconductor structure including an anodic aluminum oxide layer is described. The anodic aluminum oxide layer can include a plurality of pores extending to an adjacent surface of the semiconductor structure. A filler material can penetrate at least some of the plurality of pores and directly contact the surface of the semiconductor structure. In an illustrative embodiment, multiple types of filler material at least partially fill the pores of the aluminum oxide layer.

Abstract: Ultraviolet radiation is directed within an area. Items located within the area and/or one or more conditions of the area are monitored over a period of time. Based on the monitoring, ultraviolet radiation sources are controlled by adjusting a direction, an intensity, a pattern, and/or a spectral power of the ultraviolet radiation generated by the ultraviolet radiation source. Adjustments to the ultraviolet radiation source(s) can correspond to one of a plurality of selectable operating configurations including a storage life preservation operating configuration, a disinfection operating configuration, and an ethylene decomposition operating configuration.

Abstract: An approach for controlling ultraviolet intensity over a surface of a light sensitive object is described. Aspects involve using ultraviolet radiation with a wavelength range that includes ultraviolet-A and ultraviolet-B radiation to irradiate the surface. Light sensors measure light intensity at the surface, wherein each sensor measures light intensity in a wavelength range that corresponds to a wavelength range emitted from at least one of the sources. A controller controls the light intensity over the surface by adjusting the power of the sources as a function of the light intensity measurements. The controller uses the light intensity measurements to determine whether each source is illuminating the surface with an intensity that is within an acceptable variation with a predetermined intensity value targeted for the surface. The controller adjusts the power of the sources as a function of the variation to ensure an optimal distribution of light intensity over the surface.

Abstract: An improved heterostructure for an optoelectronic device is provided. The heterostructure includes an active region, an electron blocking layer, and a p-type contact layer. The p-type contact layer and electron blocking layer can be doped with a p-type dopant. The dopant concentration for the electron blocking layer can be at most ten percent the dopant concentration of the p-type contact layer. A method of designing such a heterostructure is also described.

Abstract: A solution for irradiating a flowing fluid through a channel with ultraviolet radiation is provided. Ultraviolet radiation sources can be located within the channel in order to direct ultraviolet radiation towards the flowing fluid and/or the interior of the channel. A valve can be located adjacent to the channel to control the flow rate of the fluid. A control system can control and adjust the ultraviolet radiation based on the flow rate of the fluid and a user input component can receive a user input for the control system to adjust the ultraviolet radiation. The ultraviolet radiation sources, the control system, the user input component, and any other components that require electricity can receive power from a rechargeable power supply. An electrical generator located within the channel can convert energy from the fluid flowing through the channel into electricity for charging the rechargeable power supply.

Abstract: A solution for illuminating an area and/or treating a substance with light, such as ultraviolet radiation, is described. The solution can use one or more solid state ultraviolet sources in conjunction with one or more ultraviolet lamps to illuminate a treatment region with ultraviolet radiation. A control component can individually operate the solid state ultraviolet source(s) and the ultraviolet lamp(s) to illuminate the treatment region with ultraviolet radiation having a predetermined minimum ultraviolet intensity.

Abstract: A device including one or more layers with lateral regions configured to facilitate the transmission of radiation through the layer and lateral regions configured to facilitate current flow through the layer is provided. The layer can comprise a short period superlattice, which includes barriers alternating with wells. In this case, the barriers can include both transparent regions, which are configured to reduce an amount of radiation that is absorbed in the layer, and higher conductive regions, which are configured to keep the voltage drop across the layer within a desired range.

Abstract: Ultraviolet radiation is directed within an area. Items located within the area and/or one or more conditions of the area are monitored over a period of time. Based on the monitoring, ultraviolet radiation sources are controlled by adjusting a direction, an intensity, a pattern, and/or a spectral power of the ultraviolet radiation generated by the ultraviolet radiation source. Adjustments to the ultraviolet radiation source(s) can correspond to one of a plurality of selectable operating configurations including a storage life preservation operating configuration, a disinfection operating configuration, and an ethylene decomposition operating configuration.

Abstract: A contact to a semiconductor layer in a light emitting structure is provided. The contact can include a plurality of contact areas formed of a metal and separated by a set of voids. The contact areas can be separated from one another by a characteristic distance selected based on a set of attributes of a semiconductor contact structure of the contact and a characteristic contact length scale of the contact. The voids can be configured to increase an overall reflectivity or transparency of the contact.

Abstract: A device comprising a semiconductor layer including a plurality of compositional inhomogeneous regions is provided. The difference between an average band gap for the plurality of compositional inhomogeneous regions and an average band gap for a remaining portion of the semiconductor layer can be at least thermal energy. Additionally, a characteristic size of the plurality of compositional inhomogeneous regions can be smaller than an inverse of a dislocation density for the semiconductor layer.

Abstract: Ultraviolet illumination with optical elements to irradiate objects and/or fluid for purposes of sterilization, disinfection, and/or cleaning. The objects and/or fluid can be irradiated using an ultraviolet illuminator having at least one ultraviolet light emitting source. An ultraviolet transparent housing encapsulates the at least one ultraviolet light emitting source. The ultraviolet transparent housing includes an ultraviolet transparent material that emits ultraviolet light from the at least one ultraviolet light emitting source while preventing humidity from penetrating the ultraviolet transparent housing and damaging the at least one ultraviolet light emitting source. At least one ultraviolet transparent optical element is located about the ultraviolet transparent housing interspersed with the ultraviolet transparent material.

Abstract: A profiled surface for improving the propagation of radiation through an interface is provided. The profiled surface includes a set of large roughness components providing a first variation of the profiled surface having a characteristic scale approximately an order of magnitude larger than a target wavelength of the radiation. The set of large roughness components can include a series of truncated shapes. The profiled surface also includes a set of small roughness components superimposed on the set of large roughness components and providing a second variation of the profiled surface having a characteristic scale on the order of the target wavelength of the radiation.

Abstract: An approach for providing illumination with a blue UV light source, which can be used in combination with a visible light source is disclosed. In operation, the visible light source emits visible light at a first intensity. The blue UV light source emits blue UV light at a second intensity. The blue UV light stimulates fluorescence from a surface of an object illuminated by the blue UV light. A sensor can detect the intensity of the fluorescence from the surface illuminated by the blue UV light source. A control module can be operatively coupled to the visible light source, the blue UV light source, and the at least one sensor, and be configured to change the intensity of the visible light and/or the intensity of the blue UV light as a function of the fluorescent intensity detected by the sensor.

Abstract: A semiconductor structure, such as a group III nitride-based semiconductor structure is provided. The semiconductor structure includes a cavity containing semiconductor layer. The cavity containing semiconductor layer can have a thickness greater than two monolayers and a multiple cavities. The cavities can have a characteristic size of at least one nanometer and a characteristic separation of at least five nanometers.

Abstract: A solution for treating a fluid, such as water, is provided. An ultraviolet transparency of a fluid can be determined before or as the fluid enters a disinfection chamber. In the disinfection chamber, the fluid can be irradiated by ultraviolet radiation to harm microorganisms that may be present in the fluid. One or more attributes of the disinfection chamber, fluid flow, and/or ultraviolet radiation can be adjusted based on the transparency to provide more efficient irradiation and/or higher disinfection rates. In addition, various attributes of the disinfection chamber, such as the position of the inlet(s) and outlet(s), the shape of the disinfection chamber, and other attributes of the disinfection chamber can be utilized to create a turbulent flow of the fluid within the disinfection chamber to promote mixing and improve uniform ultraviolet exposure.

Abstract: Ultraviolet radiation is directed within a storage area at target wavelengths, target intensities, a target temporal distribution, and/or a target spatial distribution. A set of ultraviolet radiation sources generate ultraviolet radiation directed at a set of items located within the storage area. A first ultraviolet radiation source operates at a first peak wavelength and a second ultraviolet radiation source operates at a second peak wavelength that is different from the first peak wavelength.

Abstract: A device including a first semiconductor layer and a contact to the first semiconductor layer is disclosed. An interface between the first semiconductor layer and the contact includes a first roughness profile having a characteristic height and a characteristic width. The characteristic height can correspond to an average vertical distance between crests and adjacent valleys in the first roughness profile. The characteristic width can correspond to an average lateral distance between the crests and adjacent valleys in the first roughness profile.