Abstract: A monolithic multijunction photovoltaic device is disclosed which comprises two or more photovoltaic cells between two surfaces. Each of the photovoltaic cell materials include a first region exhibiting an excess of a first charge carrier and a second region exhibiting an excess of a second charge carrier. Contacts are connected to the regions of the photovoltaic cells in configurations that allow excess current to be extracted as useful energy. In one embodiment, a first contact is electrically connected to a second region of a first material, a second contact is electrically connected to a first region of the first material, a third contact is electrically connected to a first region of a second material, and a fourth contact is electrically connected to a third material. In other embodiments, the contacts may be positioned on the surfaces of the monolithic device to minimize shadowing.

Abstract: A light emitting device includes a layer of first conductivity type, a layer of second conductivity type, and a light emitting layer disposed between the layer of first conductivity type and the layer of second conductivity type. A via is formed in the layer of second conductivity type, down to the layer of first conductivity type. The vias may be formed by, for example, etching, ion implantation, diffusion, or selective growth of at least one layer of second conductivity type. A first contact electrically contacts the layer of first conductivity type through the via. A second contact electrically contacts the layer of second conductivity type. A ring that surrounds the light emitting layer and is electrically connected to the first contact electrically contacts the layer of first conductivity type.

Abstract: A solar cell includes an active layer, a blocking layer and a contact layer. The blocking layer is disposed between a portion of the top surface of the active layer and the bottom surface of the contact layer. The blocking layer serves to reduce current flow between the contact layer and the portion of the active layer covered by the blocking layer. Current flow to the contact layer may occur via gridlines electrically connecting the active layer to the contact layer.

Abstract: The invention is a leadframe receiver package comprising a first conductive element, a solar cell electrically coupled to the first conductive element and comprising an active area, and a mold compound disposed on the leadframe and the solar cell. The mold compound defines a first aperture wall over at least a portion of the active area and a second aperture wall over at least a portion of the first conductive element. The mold compound includes a reflective surface to improve heat resistance around an aperture wall receiving solar radiation.

Abstract: A light emitting device includes a layer of first conductivity type, a layer of second conductivity type, and a light emitting layer disposed between the layer of first conductivity type and the layer of second conductivity type. A via is formed in the layer of second conductivity type, down to the layer of first conductivity type. The vias may be formed by, for example, etching, ion implantation, diffusion, or selective growth of at least one layer of second conductivity type. A first contact electrically contacts the layer of first conductivity type through the via. A second contact electrically contacts the layer of second conductivity type. A ring that surrounds the light emitting layer and is electrically connected to the first contact electrically contacts the layer of first conductivity type.

Abstract: A light emitting device includes a resonant cavity formed by a reflective metal layer and a distributed Bragg reflector. Light is extracted from the resonant cavity through the distributed Bragg reflector. A light emitting region sandwiched between a layer of first conductivity type and a layer of second conductivity type is disposed in the resonant cavity. In some embodiments, first and second contacts are formed on the same side of the resonant cavity, forming a flip chip or epitaxy up device.

Abstract: A mount for a semiconductor light emitting device includes an integrated reflector cup. The reflector cup includes a wall formed on the mount and shaped and positioned to reflect side light emitted from the light emitting device along a vertical axis of the device/mount combination. The wall may be covered by a reflective material such as a reflective metal.

Abstract: Silver electrode metallization in light emitting devices is subject to electrochemical migration in the presence of moisture and an electric field. Electrochemical migration of the silver metallization to the pn junction of the device results in an alternate shunt path across the junction, which degrades efficiency of the device. In accordance with a form of this invention, a migration barrier is provided for preventing migration of metal from at least one of the electrodes onto the surface of the semiconductor layer with which the electrode is in contact.

Abstract: A light-emitting semiconductor device includes a stack of layers including an active region. The active region includes a semiconductor selected from the group consisting of III-Phosphides, III-Arsenides, and alloys thereof. A superstrate substantially transparent to light emitted by the active region is disposed on a first side of the stack. First and second electrical contacts electrically coupled to apply a voltage across the active region are disposed on a second side of the stack opposite to the first side. In some embodiments, a larger fraction of light emitted by the active region exits the stack through the first side than through the second side. Consequently, the light-emitting semiconductor device may be advantageously mounted as a flip chip to a submount, for example.

Abstract: A structure includes semiconductor light emitting device and a wavelength converting layer. The wavelength converting layer converts a portion of the light emitted from the semiconductor light emitting device. The dominant wavelength of the combined light from the semiconductor light emitting device and the wavelength converting layer is essentially the same as the wavelength of light emitted from the device. The wavelength converting layer may emit light having a spectral luminous efficacy greater than the spectral luminous efficacy of the light emitted from the device. Thus, the structure has a higher luminous efficiency than a device without a wavelength converting layer.

Abstract: In accordance with embodiments of the invention, a light emitting device includes a light emitting region and a reflective contact separated from the light emitting region by one or more layers. In a first embodiment, the separation between the light emitting region and the reflective contact is between about 0.5?n and about 0.9?n, where ?n is the wavelength of radiation emitted from the light emitting region in an area of the device separating the light emitting region and the reflective contact. In a second embodiment, the separation between the light emitting region and the reflective contact is between about ?n and about 1.4?n. The light emitting region may be, for example, III-nitride, III-phosphide, or any other suitable material.

Abstract: A dielectric layer is formed on the mesa wall of a flip-chip LED. The dielectric layer is selected to maximize reflection of light incident at angles ranging from 10 degrees towards the substrate to 30 degrees away from the substrate. In some embodiments, the LED is a III-nitride device with a p-contact containing silver, the dielectric layer adjacent to the mesa wall is a material with a low refractive index compared to GaN, such as Al2O3.

Abstract: In accordance with the invention, a light emitting device includes a substrate, a layer of first conductivity type overlying the substrate, a light emitting layer overlying the layer of first conductivity type, and a layer of second conductivity type overlying the light emitting layer. A plurality of vias are formed in the layer of second conductivity type, down to the layer of first conductivity type. The vias may be formed by, for example, etching, ion implantation, or selective growth of the layer of second conductivity type. A set of first contacts electrically contacts the layer of first conductivity type through the vias. A second contact electrically contacts the layer of second conductivity type. In some embodiments, the area of the second contact is at least 75% of the area of the device. In some embodiments, the vias are between 2 and 100 microns wide and spaced between 5 and 1000 microns apart.

Abstract: A light-emitting semiconductor device includes a stack of layers including an active region. The active region includes a semiconductor selected from the group consisting of III-Phosphides, III-Arsenides, and alloys thereof. A superstrate substantially transparent to light emitted by the active region is disposed on a first side of the stack. First and second electrical contacts electrically coupled to apply a voltage across the active region are disposed on a second side of the stack opposite to the first side. In some embodiments, a larger fraction of light emitted by the active region exits the stack through the first side than through the second side. Consequently, the light-emitting semiconductor device may be advantageously mounted as a flip chip to a submount, for example.

Abstract: A light-emitting semiconductor device includes a stack of layers including an active region. The active region includes a semiconductor selected from the group consisting of III-Phosphides, III-Arsenides, and alloys thereof. A superstrate substantially transparent to light emitted by the active region is disposed on a first side of the stack. First and second electrical contacts electrically coupled to apply a voltage across the active region are disposed on a second side of the stack opposite to the first side. In some embodiments, a larger fraction of light emitted by the active region exits the stack through the first side than through the second side. Consequently, the light-emitting semiconductor device may be advantageously mounted as a flip chip to a submount, for example.

Abstract: In accordance with the invention, a light emitting device includes a substrate, a layer of first conductivity type overlying the substrate, a light emitting layer overlying the layer of first conductivity type, and a layer of second conductivity type overlying the light emitting layer. A plurality of vias are formed in the layer of second conductivity type, down to the layer of first conductivity type. The vias may be formed by, for example, etching, ion implantation, or selective growth of the layer of second conductivity type. A set of first contacts electrically contacts the layer of first conductivity type through the vias. A second contact electrically contacts the layer of second conductivity type. In some embodiments, the area of the second contact is at least 75% of the area of the device. In some embodiments, the vias are between 2 and 100 microns wide and spaced between 5 and 1000 microns apart.

Abstract: A dielectric layer is formed on the mesa wall of a flip-chip LED. The dielectric layer is selected to maximize reflection of light incident at angles ranging from 10 degrees towards the substrate to 30 degrees away from the substrate. In some embodiments, the LED is a III-nitride device with a p-contact containing silver, the dielectric layer adjacent to the mesa wall is a material with a low refractive index compared to GaN, such as Al2O3.

Abstract: In accordance with embodiments of the invention, a light emitting device includes a light emitting region and a reflective contact separated from the light emitting region by one or more layers. In a first embodiment, the separation between the light emitting region and the reflective contact is between about 0.5&lgr;n and about 0.9&lgr;n, where &lgr;n is the wavelength of radiation emitted from the light emitting region in an area of the device separating the light emitting region and the reflective contact. In a second embodiment, the separation between the light emitting region and the reflective contact is between about &lgr;n and about 1.4&lgr;n. The light emitting region may be, for example, III-nitride, III-phosphide, or any other suitable material.

Abstract: A method for growing a crystalline layer that includes a first material on a growth surface of a crystalline substrate of a second material, wherein the first material and the second material have different lattice constants. A buried layer is generated in the substrate such that the buried layer isolates a layer of the substrate that includes the growth surface from the remainder of the substrate. The second material is then deposited on the growth surface at a growth temperature. The isolated layer of the substrate has a thickness that is less than the thickness at which defects are caused in the crystalline lattice of the first material by the second material crystallizing thereon. The buried layer is sufficiently malleable at the growth temperature to allow the deformation of the lattice of the isolated layer without deforming the remainder of the substrate. The present invention may be utilized for growing III-V semiconducting material layers on silicon substrates.

Abstract: A light-emitting semiconductor device includes a stack of layers including an active region. The active region includes a semiconductor selected from the group consisting of III-Phosphides, III-Arsenides, and alloys thereof. A superstrate substantially transparent to light emitted by the active region is disposed on a first side of the stack. First and second electrical contacts electrically coupled to apply a voltage across the active region are disposed on a second side of the stack opposite to the first side. In some embodiments, a larger fraction of light emitted by the active region exits the stack through the first side than through the second side. Consequently, the light-emitting semiconductor device may be advantageously mounted as a flip chip to a submount, for example.