Abstract:
A device having a layer with a patterned surface for improving the growth of semiconductor layers, such as group III nitride-based semiconductor layers with a high concentration of aluminum, is provided. The patterned surface can include a substantially flat top surface and a plurality of stress reducing regions, such as openings. The substantially flat top surface can have a root mean square roughness less than approximately 0.5 nanometers, and the stress reducing regions can have a characteristic size between approximately 0.1 microns and approximately five microns and a depth of at least 0.2 microns. A layer of group-III nitride material can be grown on the first layer and have a thickness at least twice the characteristic size of the stress reducing regions.
Abstract:
A switch includes an input contact and an output contact to a conducting channel. At least one of the input and output contacts is capacitively coupled to the conducting channel. A control contact is located outside of a region between the input and output contacts, and can be used to adjust the switch between on and off operating states. The switch can be implemented as a radio frequency switch in a circuit.
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:
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:
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 circuit including a semiconductor device having a set of space-charge control electrodes is provided. The set of space-charge control electrodes is located between a first terminal, such as a gate or a cathode, and a second terminal, such as a drain or an anode, of the device. The circuit includes a biasing network, which supplies an individual bias voltage to each of the set of space-charge control electrodes. The bias voltage for each space-charge control electrode can be: selected based on the bias voltages of each of the terminals and a location of the space-charge control electrode relative to the terminals and/or configured to deplete a region of the channel under the corresponding space-charge control electrode at an operating voltage applied to the second terminal.
Abstract:
A patterned surface for improving the growth of semiconductor layers, such as group III nitride-based semiconductor layers, is provided. The patterned surface can include a set of substantially flat top surfaces and a plurality of openings. Each substantially flat top surface can have a root mean square roughness less than approximately 0.5 nanometers, and the openings can have a characteristic size between approximately 0.1 micron and five microns. One or more of the substantially flat top surfaces can be patterned based on target radiation.
Abstract:
A diffusive illuminator is provided. The diffusive illuminator includes a set of light sources and a light guiding structure including a plurality of layers. At least some of the layers can be formed of a fluoropolymer and at least one layer can be formed of a transparent fluid. The light guiding structure also includes an emission surface through which diffused light exits. The light guiding structure can further include diffusive elements associated with at least one of the plurality of layers. Each diffusive element can diffuse the light to within forty percent of Lambertian distribution. The diffusive elements can be arranged based on a desired uniformity of the diffused light at a target distance corresponding to a surface to be illuminated. The diffusive illuminator can emit ultraviolet light, and can be implemented as part of a disinfection system.
Abstract:
A solution for packaging an optoelectronic device using an ultraviolet transparent polymer is provided. The ultraviolet transparent polymer material can be placed adjacent to the optoelectronic device and/or a device package on which the optoelectronic device is mounted. Subsequently, the ultraviolet transparent polymer material can be processed to cause the ultraviolet transparent polymer material to adhere to the optoelectronic device and/or the device package. The ultraviolet transparent polymer can be adhered in a manner that protects the optoelectronic device from the ambient environment.
Abstract:
A device having a channel with multiple voltage thresholds is provided. The channel can include a first section located adjacent to a source electrode, which is a normally-off channel and a second section located between the first section and a drain electrode, which is a normally-on channel. The device can include a charge-controlling electrode connected to the source electrode, which extends from the source electrode over at least a portion of the second section of the channel. During operation of the device, a potential difference between the charge-controlling electrode and the channel can control the on/off state of the normally-on section of the channel.