Abstract: A one-axis azimuth sun-tracking carousel where the PV panels are mounted at a fixed tilt in operation can be mounted on a flat roof building without roof penetration and without risk of wind damage. The carousel is prefabricated and sized to carry the maximum power while still fitting in a standard shipping container. Panel support arms fold down for shipping or in the event of a hurricane to make the carousel less than 9 inches high. Because this carousel is prefabricated and compact, it can be easily hoisted up on a roof for rapid low-cost installation. Wind skirts provide low wind resistance in high wind situations during normal operation. In order to survive high winds without roof penetration, wire tether tie points allow several carousels in an array to be tethered together and to the building parapet walls.

Abstract: A solar PV panel has an array of primary mirrors that collects and reflects solar radiation toward an array of dichroic secondary elements. The dichroic secondary elements reflect near-visible solar radiation to an array of near-visible radiation sensitive solar cells and simultaneously transmit infrared radiation to an array of infrared sensitive solar cells. The array of near-visible radiation sensitive cells and the array of infrared sensitive cells are wired in series. The optical properties of the dichoic secondary element, near-visible radiation sensitive cell, and IR sensitive cell are chosen for simultaneous maximum power production from the panel.

Abstract: A planar concentrator solar power module has a planar base, an aligned array of linear photovoltaic cell circuits on the base and an array of linear Fresnel lenses or linear mirrors for directing focused solar radiation on the aligned array of linear photovoltaic cell circuits. The cell circuits are mounted on a back panel which may be a metal back plate. The cell circuit area is less than a total area of the module. Each linear lens or linear mirror has a length greater than a length of the adjacent cell circuit. The cell circuit may have cells mounted in shingle fashion to form a shingled-cell circuit. In an alternative module, linear extrusions on the circuit element have faces for mounting the linear mirrors for deflecting sun rays impinging on each mirror onto the shingled-cells. The linear extrusions are side-wall and inner extrusions with triangular cross-sections. The circuit backplate is encapsulated by lamination for weather protection.

Abstract: A planar concentrator solar power module has a planar base, an aligned array of linear photovoltaic cell circuits on the base and an array of linear Fresnel lenses or linear mirrors for directing focused solar radiation on the aligned array of linear photovoltaic cell circuits. The cell circuits are mounted on a back panel which may be a metal back plate. The cell circuit area is less than a total area of the module. Each linear lens or linear mirror has a length greater than a length of the adjacent cell circuit. The cell circuit may have cells mounted in shingle fashion to form a shingled-cell circuit. In an alternative module, linear extrusions on the circuit element have faces for mounting the linear mirrors for deflecting sun rays impinging on each mirror onto the shingled-cells. The linear extrusions are side-wall and inner extrusions with triangular cross-sections. The circuit backplate is encapsulated by lamination for weather protection.

Abstract: An acousto-optic modulator includes a (100), (010) or (001) single crystal silicon acousto-optic interaction medium, and at least one transducer for emitting an acoustic wave attached to the single crystal. The transducer has a first electrode layer disposed on one side and a second electrode layer disposed on its other side. The transducer is aligned to the single crystal so that the direction of acoustic propagation in the silicon crystal is substantially along the (100), (010) or (001) direction. A q-switched laser includes a modulator according to the invention.

Abstract: A process for creating a broadly tunable Distributed Bragg Reflector (DBR) with a reduced recombination rate. According to the current invention, this may be achieved by creating electron confinement regions and hole confinement regions in the waveguide of the DBR. Preferably, this is achieved by engineering the band gaps of the DBR waveguide and cladding materials. Preferably, the materials selected for use in the DBR may be lattice matched. Alternately, two or more thin electron confinement regions and two or more thin hole confinement regions may be created to take advantage of strain compensation in thinner layers thereby broadening the choices of materials appropriate for use in creating a broadly tunable DBR. Alternately, graded materials and/or graded interfaces may be created according to alternate processes according to the current invention to provide effective electron and/or hole confinement regions in various DBR designs.

Abstract: An emitter for use with a generator has a tube closed at one end, heated from its outside with a water-cooled photovoltaic converter array mounted inside for glass-melting application. Several TPV tubes may be inserted through holes in the insulation into the port sections between the glass-melting furnace and the regenerators. Any one of these tubes may be removed for maintenance at any time and replaced with a closure to close off the hole, without affecting the industrial process. The emitter tube may be a SiC or KANTHAL tube. The tube may be lines on its inside with AR coated tungsten foil or the tungsten may be deposited on the inner tube surface as a film followed by the AR coating. The photovoltaic converter array may comprise a polygonal array of shingle circuits where the circuits are fabricated using low bandgap GaSb cells.

Abstract: Our cylindrical TPV generator uses low bandgap PV cells mounted on circuits in a polygonal array around an IR emitter. The combustion gases are completely contained within the radiant tube burner. The PV array is mounted inside a leak-tight envelope cooled on its outer surface by either water or air flow. Flanges on either end of this PV array container allow for hermetic seals. A folded back coaxial emitter support tube provides a long path length limiting thermal conduction along its cylindrical wall from the very hot emitter section to the cooled seal flange. In our improved cylindrical TPV generator, we provide for a low temperature catalytic after-burn by providing a perforated turnaround plate coupling between the inner disk stack and the outer disk stack. This perforated turnaround plate provides a small amount of combustion air for the after-burn. A catalyst coating can be provided on the hotter surface of the outer finned disks. The after-burn occurs in the outer finned disk stack.

Abstract: A hydrocarbon thermophotovoltaic (TPV)electric generator insert has applications as a replacement burner to retrofit existing appliances. The retrofitted appliance is thus upgraded to either a cogeneration or self-powered unit. The design of the TPV burner insert is independent of the appliance to be retrofitted except for external adapters and can be easily retrofitted to any appliance design requiring a hydrocarbon burner. The burner uses fully premixed air and fuel near stoichiometry to attain a short duration, high intensity burn through optically dense porous ceramic emitters. The emitters attain temperatures between 1300° and 1500° C. The infrared radiation is collected by low bandgap photovoltaic cells with optical response at least out to a wavelength of 1.7 micrometers such as GaSb cells to produce DC power. The circuit cooling system uses fans or circulating water for cooling.

Abstract: An integrated surface emitting laser and modulator device is disclosed that includes a detector for monitoring the optical power output of the laser and another detector for monitoring an extinction ratio of the modulator. A cleave physically and electrically separates the laser from the modulator device. The device has a collimating lens disposed on a top surface.

Abstract: A wavelength-tunable distributed feedback (DFB) laser is disclosed where the lasing wavelength can be adjusted by adjusting the bias current of the laser diode. Since the output power of the laser diode also changes with the bias current, a one-to-one correspondence between the lasing wavelength and the output power of the laser can be established. Consequently, the lasing wavelength can be measured directly from the photocurrent of a power monitoring detector facing the back-end of the laser diode. This provides an extremely simple method for wavelength monitoring.

Abstract: A wavelength-tunable distributed feedback (DFB) laser is disclosed where the lasing wavelength can be adjusted by adjusting the bias current of the laser diode. Since the output power of the laser diode also changes with the bias current, a one-to-one correspondence between the lasing wavelength and the output power of the laser can be established. Consequently, the lasing wavelength can be measured directly from the photocurrent of a power monitoring detector facing the back-end of the laser diode. This provides an extremely simple method for wavelength monitoring.

Abstract: A method is disclosed for separating a semiconductor epitaxial structure from an insulating growth substrate. The method utilizes electrochemical anodic reactions to remove a thin etch layer disposed near the growth interface. The thin etch layer can be an intentional layer made of a material different from the epitaxial structure and/or can include a material with a high defect density. The method can be applied in the fabrication of optoelectronic and electronic devices from III-V materials, in particular gallium-nitride based materials.

Abstract: This invention describes a method for fabricating light-emitting diodes with an improved external quantum efficiency on a transparent substrate. The LED device structure is mounted face-down on and bonded to a handling wafer. The LED dies on the transparent substrate are separated by applying mutually aligned separation cuts from both sides of the transparent substrate and by then cutting through the handling wafer and the substrate wafer. This method allow the use of substrates that are difficult to thin and cleave. Contacts can be applied from one side of the devices only. The method is suitable for low cost high volume manufacturing.

Abstract: An avalanche photodetector (APD) is made from composite semiconductor materials. The absorption region of the APD is formed in a n-type InGaAs layer. The multiplication region of the APD is formed in a p-type silicon layer. The two layers are bonded together. The p-type silicon layer may be supported on an n+ type silicon substrate. A p-n junction formed at the interface between the silicon layer and the substrate. Alternatively, the n-type InGaAs layer may be supported on an InP substrate. In this case, a p-n junction is formed by making n-doped surface regions in the p-type silicon superlayer. In either case, the p-n junction is reverse biased for avalanche multiplication of charge carriers. The maximum of the electric field distribution in the APD under reverse bias operating conditions is located at p-n junction. This maximum is at a distance equal to about the thickness of the p-type silicon layer away from the absorption region.

Abstract: A planar avalanche photodetector (APD) is fabricated by forming a, for example, InGaAs absorption layer on a p+-type semiconductor substrate, such as InP, and wafer-bonding to the absorption layer a second p-type semiconductor, such as Si, to form a multiplication layer. The layer thickness of the multiplication layer is substantially identical to that of the absorption layer. A region in a top surface of the p-type Si multiplication layer is doped n+-type to form a carrier separation region and a high electric field in the multiplication region. The APD can further include a guard-ring to reduce leakage currents as well as a resonant mirror structure to provide wavelength selectivity. The planar geometry furthermore favors the integration of high-speed electronic circuits on the same substrate to fabricate monolithic optoelectronic transceivers.

Abstract: A method for producing a stress-engineered substrate includes selecting first and second materials for forming the substrate. An epitaxial material for forming a heteroepitaxial layer is then selected. If the lattice constant of the heteroepitaxial layer (aepi) is greater than that (asub) of the immediate substrate layer the epitaxial layer is deposited on, then the epitaxial layer is kept under “compressive stress” (negative stress) at all temperatures of concern. On the other hand, if the lattice constant of the heteroepitaxial layer (aepi) is less than that (asub) of the immediate substrate layer the epitaxial layer is deposited on, then the epitaxial layer is kept under “tensile stress” (positive stress). The temperatures of concern range from the annealing temperature to the lowest temperature where dislocations are still mobile.

Abstract: A planar avalanche photodetector (APD) is fabricated by forming a, for example, InGaAs absorption layer on a p+-type semiconductor substrate, such as InP, and wafer-bonding to the absorption layer a second p-type semiconductor, such as Si, to form a multiplication layer. The layer thickness of the multiplication layer is substantially identical to that of the absorption layer. A region in a top surface of the p-type Si multiplication layer is doped n+-type to form a carrier separation region and a high electric field in the multiplication region. The APD can further include a guard-ring to reduce leakage currents as well as a resonant mirror structure to provide to wavelength selectivity. The planar geometry furthermore favors the integration of high-speed electronic circuits on the same substrate to fabricate monolithic optoelectronic transceivers.

Abstract: The method of the present invention is used to join two dissimilar materials together, and particularly to transfer a film to a substrate when the difference in thermal expansion coefficients between the film and the substrate is very big. A hydrophilic surface is created on one material and an atmosphere reactive metal element is deposited on the surface of another material. When the materials are tightly contacted, with the reactive element pressed against the hydrophilic surface, the reactive metal element reacts with the moisture from the hydrophilic surface at room temperature. Strong bonds form during the reaction joining the two materials together. Because the procedure takes place at room temperature, extremely low stress is built in. The film joining is successful even with a big thermal expansion coefficient difference between the materials, such as exist between GaAs and silicon and between silicon and sapphire.

Abstract: Two-terminal circuit has top and bottom cells bonded to an insulating substrate with the top cells bonded on top of the bottom cells. Bottom cells are connected in series through ribbon bonds. Top cells are connected in parallel through ribbon bonds. The ribbon bonds connect to the topsides of the top and bottom cells. The substrate contains metal die bonding pads for the base contacts to the bottom cells. Metal traces are provided for ribbon bond connections to emitter contacts for the bottom cells. A metal trace becomes a positive terminal pad for the bottom cells and a negative terminal for a second pad for the bottom cells. Two cell assemblies may be series connected by connecting positive top cell output connectors with negative pads of top cells in adjacent cell assemblies, and by connecting positive bottom cell output connectors with negative pads of bottom cells in adjacent assemblies.