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 method of fabricating a device using 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 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: An emitting structure for simulating an irradiance signature of a missile is provided. The emitting structure includes one or more radiation sources, each of which includes at least one ultraviolet radiation source and at least one infrared radiation source. The emitting structure also includes a spherical shell and a mechanism for positioning the radiation source(s) along a three dimensional boundary of the spherical shell. The emitting structure can locate and operate one of the radiation sources to simulate the irradiance signature of the missile.

Abstract: A solution for forming an ohmic contact to a semiconductor layer is provided. A masking material is applied to a set of contact regions on the surface of the semiconductor layer. Subsequently, one or more layers of a device heterostructure are formed on the non-masked region(s) of the semiconductor layer. The ohmic contact can be formed after the one or more layers of the device heterostructure are formed. The ohmic contact formation can be performed at a processing temperature lower than a temperature range within which a quality of a material forming any semiconductor layer in the device heterostructure is damaged.

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. One or more of a set of growth conditions, a thickness of one or both of the layers, and/or a lattice mismatch between the layers can be configured to create a target level of compressive and/or shear stress within a minimum percentage of the interface between the layers.

Abstract: A light emitting diode is provided, which includes an n-type contact layer and a light generating structure adjacent to the n-type contact layer. The light generating structure includes a set of quantum wells. The contact layer and light generating structure can be configured so that a difference between an energy of the n-type contact layer and an electron ground state energy of a quantum well is greater than an energy of a polar optical phonon in a material of the light generating structure. Additionally, the light generating structure can be configured so that its width is comparable to a mean free path for emission of a polar optical phonon by an electron injected into the light generating structure.

Abstract: A contact including an ohmic layer and a reflective layer located on the ohmic layer is provided. The ohmic layer is transparent to radiation having a target wavelength, while the reflective layer is at least approximately eighty percent reflective of radiation having the target wavelength. The target wavelength can be ultraviolet light, e.g., having a wavelength within a range of wavelengths between approximately 260 and approximately 360 nanometers.

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 device including one or more low-conducting layers is provided. A low-conducting layer can be located below the channel and one or more attributes of the low-conducting layer can be configured based on a minimum target operating frequency of the device and a charge-discharge time of a trapped charge targeted for removal by the low-conducting layer or a maximum interfering frequency targeted for suppression using the low-conducting layer. For example, a product of the lateral resistance and a capacitance between the low-conducting layer and the channel can be configured to be larger than an inverse of the minimum target operating frequency and the product can be smaller than at least one of: the charge-discharge time or an inverse of the maximum interfering frequency.

Abstract: A composite material, which can be used as an encapsulant for an ultraviolet device, is provided. The composite material includes a matrix material and at least one filler material incorporated in the matrix material that are both at least partially transparent to ultraviolet radiation of a target wavelength. The filler material includes microparticles and/or nanoparticles and can have a thermal coefficient of expansion significantly smaller than a thermal coefficient of expansion of the matrix material for relevant atmospheric conditions. The relevant atmospheric conditions can include a temperature and a pressure present during each of: a curing and a cool down process for fabrication of a device package including the composite material and normal operation of the ultraviolet device within the device package.

Abstract: A carbon doped short period superlattice is provided. A heterostructure includes a short period superlattice comprising a plurality of quantum wells alternating with a plurality of barriers. One or more of the quantum wells and/or the barriers includes a percolated carbon atomic plane.

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.