Abstract: Implantable medical systems enter an exposure mode of operation, either manually via a down linked programming instruction or by automatic detection by the implantable system of exposure to a magnetic disturbance. A controller then determines the appropriate exposure mode by considering various pieces of information including the device type including whether the device has defibrillation capability, pre-exposure mode of therapy including which chambers have been paced, and pre-exposure cardiac activity that is either intrinsic or paced rates. Additional considerations may include determining whether a sensed rate during the exposure mode is physiologic or artificially produced by the magnetic disturbance. When the sensed rate is physiologic, then the controller uses the sensed rate to trigger pacing and otherwise uses asynchronous pacing at a fixed rate.

Abstract: Compound semiconductor alloys comprising dilute nitride materials, are materials used in absorbing layers for photodetectors, power converters, solar cells, and in particular to high efficiency, electronic and optoelectronic devices, including multijunction solar cells, photodetectors, power converters, and the like, formed primarily of III-V semiconductor alloys. The absorbing (or active) layers achieve improved characteristics including band gap optimization and minimization of defects.

Abstract: Multijunction solar cells having at least four subcells are disclosed, in which at least one of the subcells comprises a base layer formed of an alloy of one or more elements from group III on the periodic table, nitrogen, arsenic, and at least one element selected from the group consisting of Sb and Bi, and each of the subcells is substantially lattice matched. Methods of manufacturing solar cells and photovoltaic systems comprising at least one of the multijunction solar cells are also disclosed.

Abstract: A multi junction solar cell is provided with a non-alloyed ohmic contact metallization stack by inversion of the top semiconductor layer from n-type to p-type and including the utilization of a tunnel junction. Alternatively, the non-alloyed ohmic contact can be achieved by changing the top semiconductor layer from a higher bandgap material to a lower bandgap material.

Abstract: Multijunction solar cells having at least four subcells are disclosed, in which at least one of the subcells comprises a base layer formed of an alloy of one or more elements from group III on the periodic table, nitrogen, arsenic, and at least one element selected from the group consisting of Sb and Bi, and each of the subcells is substantially lattice matched. Methods of manufacturing solar cells and photovoltaic systems comprising at least one of the multijunction solar cells are also disclosed.

Abstract: In a solar cell having one or more subcells, at least one subcell is provided with a reverse heterojunction, the reverse heterojunction being formed with an emitter and an adjacent base, wherein the emitter has a band gap that is at least 10 meV lower than that of the adjacent base in order to reduce sheet resistance of the emitter and/or increase the subcell current with minimal effect on the open-circuit voltage. Because of the increase in current, the decrease in emitter sheet resistance, and relatively unchanged open-circuit voltage of the subcell, the efficiency of a solar cell employing one or more subcells with reverse heterojunctions is enhanced.

Abstract: Multijunction solar cells having at least four subcells are disclosed, in which at least one of the subcells comprises a base layer formed of an alloy of one or more elements from group III on the periodic table, nitrogen, arsenic, and at least one element selected from the group consisting of Sb and Bi, and each of the subcells is substantially lattice matched. Methods of manufacturing solar cells and photovoltaic systems comprising at least one of the multijunction solar cells are also disclosed.

Abstract: Photovoltaic cells with one or more subcells are provided with a wide band gap, pseudomorphic window layer of at least 15 nm in thickness and with an intrinsic material lattice constant that differs by at least 1% from an adjacent emitter layer. This window layer has a higher band gap than a window layer with substantially the same intrinsic material lattice constant as the adjacent emitter layer, which increases the light transmission through the window, thereby increasing the current generation in the solar cell. The quality of being pseudomorphic material preserves a good interface between the window and the emitter, reducing the minority carrier surface recombination velocity. A method is provided for building a wide band gap, pseudomorphic window layer of a photovoltaic cell that has an intrinsic material lattice constant that differs by at least 1% from the adjacent emitter layer.

Abstract: A multilayer window structure for a solar cell comprises one or more layers where the bottom layer has an intrinsic material lattice spacing that is substantially the same as the emitter in the plane perpendicular to the direction of epitaxial growth. One or more upper layers of the window structure has progressively higher band gaps than the bottom layer and has intrinsic material lattice spacing is substantially different than the emitter intrinsic material lattice spacing.

Abstract: Multijunction solar cells having at least four subcells are disclosed, in which at least one of the subcells comprises a base layer formed of an alloy of one or more elements from group III on the periodic table, nitrogen, arsenic, and at least one element selected from the group consisting of Sb and Bi, and each of the subcells is substantially lattice matched. Methods of manufacturing solar cells and photovoltaic systems comprising at least one of the multijunction solar cells are also disclosed.

Abstract: In a solar cell having one or more subcells, at least one subcell is provided with a reverse heterojunction, the reverse heterojunction being formed with an emitter and an adjacent base, wherein the emitter has a band gap that is at least 10 meV lower than that of the adjacent base in order to reduce sheet resistance of the emitter and/or increase the subcell current with minimal effect on the open-circuit voltage. Because of the increase in current, the decrease in emitter sheet resistance, and relatively unchanged open-circuit voltage of the subcell, the efficiency of a solar cell employing one or more subcells with reverse heterojunctions is enhanced.

Abstract: A multilayer window structure for a solar cell comprises one or more layers where the bottom layer has an intrinsic material lattice spacing that is substantially the same as the emitter in the plane perpendicular to the direction of epitaxial growth. One or more upper layers of the window structure has progressively higher band gaps than the bottom layer and has intrinsic material lattice spacing is substantially different than the emitter intrinsic material lattice spacing.

Abstract: Photovoltaic cells with one or more subcells are provided with a wide band gap, pseudomorphic window layer of at least 15 nm in thickness and with an intrinsic material lattice constant that differs by at least 1% from an adjacent emitter layer. This window layer has a higher band gap than a window layer with substantially the same intrinsic material lattice constant as the adjacent emitter layer, which increases the light transmission through the window, thereby increasing the current generation in the solar cell. The quality of being pseudomorphic material preserves a good interface between the window and the emitter, reducing the minority carrier surface recombination velocity. A method is provided for building a wide band gap, pseudomorphic window layer of a photovoltaic cell that has an intrinsic material lattice constant that differs by at least 1% from the adjacent emitter layer.

Abstract: An “n-on-p” type multijunction solar cell structure is disclosed using an n-type substrate for the epitaxial growth of III-V semiconductor material, wherein a “p-on-n” tunnel junction diode is disposed between the substrate and one or more heteroepitaxial layers of III-V semiconductor materials.

Abstract: Tunnel junctions are improved by providing a rare earth-Group V interlayer such as erbium arsenide (ErAs) to yield a mid-gap state-assisted tunnel diode structure. Such tunnel junctions survive thermal energy conditions (time/temperature) in the range required for dilute nitride material integration into III-V multi-junction solar cells.