Abstract: A semiconductor high electron mobility transistor (HEMT)-based device configured to detect ionizing radiation, wherein the device comprises: a substrate; a nucleation layer formed on the substrate; a gallium nitride (GaN) buffer layer arranged on the nucleation layer; a GaN channel layer arranged on the GaN buffer layer; an aluminum nitride (A1N) spacer layer arranged on the GaN channel layer; a barrier layer arranged on the A1N spacer layer; a GaN cap layer arranged on the barrier layer; an electrically insulating silicon nitride (SiNx) passivation layer arranged on the GaN cap layer; a source, a drain and a gate, wherein the source and the drain are formed on the GaN cap layer; wherein charge carriers generated by the radiation in the underlying GaN layers are collected in the GaN channel layer and multiplied by impact ionization by a high electric field at the gate edge facing the drain contact.

Abstract: An ohmic contact includes a first semiconductor layer a second semiconductor layer, and a heterointerface between the first semiconductor layer and the second semiconductor layer. The second semiconductor layer has a two-dimensional electron sheet region in which a two-dimensional electron sheet is formed. The ohmic contact further includes a metal terminal covering the first semiconductor layer and filling a plurality of direct access pathways that provide direct lateral contact with the two-dimensional electron sheet region. The semiconductor device is fabricated by providing the semiconductor layers, etching the direct access pathways, and depositing metal material to fill the direct access pathways and cover the semiconductor layers.

Abstract: An ohmic contact includes a first semiconductor layer a second semiconductor layer, and a heterointerface between the first semiconductor layer and the second semiconductor layer. The second semiconductor layer has a two-dimensional electron sheet region in which a two-dimensional electron sheet is formed. The ohmic contact further includes a metal terminal covering the first semiconductor layer and filling a plurality of direct access pathways that provide direct lateral contact with the two-dimensional electron sheet region. The semiconductor device is fabricated by providing the semiconductor layers, etching the direct access pathways, and depositing metal material to fill the direct access pathways and cover the semiconductor layers.

Abstract: Deposition of thin film dielectrics, and in particular for chemical vapor deposition of nano-layer structures comprising multiple layers of dielectrics, such as, silicon dioxide, silicon nitride, silicon oxynitride, and/or other silicon compatible dielectrics includes post-deposition surface treatment of deposited layers with a metal or semiconductor source gas, e.g., a silicon source gas. Deposition of silicon containing dielectrics comprises silane-based chemistry for deposition of doped or undoped dielectric layers, and surface treatment of deposited dielectric layers with silane. Surface treatment provides dielectric layers with improved layer-to-layer uniformity and lateral continuity, and substantially atomically flat dielectric layers suitable for multilayer structures for electroluminescent light emitting structures, e.g., active layers containing rare earth containing luminescent centers.

Abstract: A method is disclosed for deposition of thin film dielectrics, and in particular for chemical vapour deposition of nano-layer structures comprising multiple layers of dielectrics, such as, silicon dioxide, silicon nitride, silicon oxynitride and/or other silicon compatible dielectrics. The method comprises post-deposition surface treatment of deposited layers with a metal or semiconductor source gas, e.g. a silicon source gas. Deposition of silicon containing dielectrics preferably comprises silane-based chemistry for deposition of doped or undoped dielectric layers, and surface treatment of deposited dielectric layers with silane. Surface treatment provides dielectric layers with improved layer-to-layer uniformity and lateral continuity, and substantially atomically flat dielectric layers suitable for multilayer structures for electroluminescent light emitting structures, e.g. active layers containing rare earth containing luminescent centres.

Abstract: A thin film electro-luminescent device (TFEL) includes an active layer made of a direct bandgap semiconductor material, e.g. zinc oxide, doped with exciton binding centers, such as aluminum, in small amounts, e.g. 0.001 at % to 30.0 at %. The exciton binding centers prevent free excitons, created by impact ionization, from diffusing toward and recombining at native defect centers. To provide a columnar structure, a polycrystalline seed layer is deposited first to provide a template, followed by the deposition of an overlying layer forming columns in accordance with the template.

Abstract: Electroluminescent (EL) devices structures are provided comprising a hot electron stopper layer structure to capture hot electrons and dissipate their energy, thereby reducing damage to the transparent conducting oxide (TCO) layer and reducing other hot electron effects, such as charging effects, which impact reliability of EL device structures. The stopper layer structure may comprise a single layer or multiple layers provided between the TCO electrode layer and the emitter structure, and may also function to reduce diffusion or chemical interactions between the TCO and the emitter layer structure. Optionally, stopper layers may also be provided within the emitter structure. Suitable stopper layer materials are wideband gap semiconductors or dielectrics, preferably transparent at wavelengths emitted by the EL device characterized by high impact ionization rates, and/or high relative permittivity relative to adjacent layers of the emitter structure.

Abstract: Electroluminescent (EL) devices structures are provided comprising a hot electron stopper layer structure to capture hot electrons and dissipate their energy, thereby reducing damage to the transparent conducting oxide (TCO) layer and reducing other hot electron effects, such as charging effects, which impact reliability of EL device structures. The stopper layer structure may comprise a single layer or multiple layers provided between the TCO electrode layer and the emitter structure, and may also function to reduce diffusion or chemical interactions between the TCO and the emitter layer structure. Optionally, stopper layers may also be provided within the emitter structure. Suitable stopper layer materials are wideband gap semiconductors or dielectrics, preferably transparent at wavelengths emitted by the EL device characterized by high impact ionization rates, and/or high relative permittivity relative to adjacent layers of the emitter structure.

Abstract: A thin film electro-luminescent device (TFEL) includes an active layer made of a direct bandgap semiconductor material, e.g. zinc oxide, doped with exciton binding centers, such as aluminum, in small amounts, e.g. 0.001 at % to 30.0 at %. The exciton binding centers prevent free excitons, created by impact ionization, from diffusing toward and recombining at native defect centers. To provide a columnar structure, a polycrystalline seed layer is deposited first to provide a template, followed by the deposition of an overlying layer forming columns in accordance with the template.

Abstract: The present invention relates to a sol-gel deposition/heat treatment process, which consistently produces polycrystalline direct bandgap semiconductor, e.g. ZnO, thin films exhibiting a photo luminescent (PL) spectrum at room temperature that is dominated by a single peak, e.g. in the ultraviolet part of the spectrum, in which the PL intensity of the bandgap emission is more than approximately 40 times greater than any deep-level defect emission peak or band. The present invention incorporates such direct bandgap semiconductor, e.g. ZnO, polycrystalline thin films produced by the method of the present invention into electro-luminescent devices that exhibit similarly high ratios of bandgap/deep-level defect emission intensity.

Abstract: A technique for hermetically sealing an optical component in a metal package is described. Variations of the technique are described in which optical communication between the optical component and the outside environment is achieved with a ribbon fibre.

Abstract: A technique for hermetically sealing an optical component in a metal package is described. Variations of the technique are described in which optical communication between the optical component and the outside environment is achieved with a ribbon fibre.

Abstract: An optical wavelength selective device is provided that is particularly useful as a demultiplexer. The device is made from a planar slab optical waveguide material transmissive to light. Perturbations in the form of holes are etched into the slab waveguide cladding or preferably into the core of the waveguide thereby changing the effective refractive index of regions within the core. The holes are very closely spaced and form a transmissive optical grating, having dimensions suitable for operating in the Raman-Nath regime. Mirrors or lenses are formed within the device for guiding an input beam into the waveguide as a parallel light source.

Abstract: A thin reflecting disk tightly bears on one edge of a case for defining a closed volume, means being provided in the latter for producing a negative pressure, and the bottom of the case is provided with supports arranged in parallel rows of three supoprts, a small beam being advantageously interposed between the disk and each row of supports when this mirror is used for focusing a laser beam, it is possible, by simply regulating the supports, to modify the shape of the disk so as to, e.g. obtain a rectilinear focal zone and a constant energy concentration of the beam along the zone.

Abstract: A laser beam alignment device which has a movable beam-deflection mirror, two motors for modifying the orientation of the mirror, two incremental coders associated with the motors, a thermoelectric detector placed between the target to be reached by the beam and the deflection mirror and able to supply voltage differences in accordance with the misalignment of the beam and an electronic processing system for controlling the motors as a function of voltage differences and pulses produced by the coders, so as to keep the beam aligned on the target.

Abstract: A measured-force gripper device of articulated structure having several degrees of freedom and interposed between the contact plate and its support, the device comprising two fingers which can be displaced to grasp an article to be handled, each finger being formed by a support, a contact plate which contacts the article to be handled, an articulated structure, which has several degrees of freedom and is interposed between the contact plate and the support, and a displacement-measuring pickup associated with each of the degrees of freedom of each finger, the pickup delivering information related exclusively to the movements carried out in accordance with that degree of freedom.

Abstract: Apparatus for transmitting a beam of energy includes a first arm formed by a hollow tube, which is rotatable about its own axis, a second arm formed by two half-arms, arranged symmetrically with respect to the axis of the first tube and movable with respect thereto by means of an articulation, and a third arm formed by a hollow tube, articulated to the half-arms by two intermediate parts.