Abstract: A device structure includes a III-nitride wurtzite semiconductor light emitting region disposed between a p-type region and an n-type region. A bonded interface is disposed between two surfaces, one of the surfaces being a surface of the device structure. The bonded interface facilitates an orientation of the wurtzite c-axis in the light emitting region that confines carriers in the light emitting region, potentially increasing efficiency at high current density.

Abstract: A semiconductor light emitting device includes an in-plane active region that emits linearly-polarized light. An in-plane active region may include, for example, a {11 20} or {10 10} InGaN light emitting layer. In some embodiments, a polarizer oriented to pass light of a polarization of a majority of light emitted by the active region serves as a contact. In some embodiments, two active regions emitting the same or different colored light are separated by a polarizer oriented to pass light of a polarization of a majority of light emitted by the bottom active region, and to reflect light of a polarization of a majority of light emitted by the top active region. In some embodiments, a polarizer reflects light scattered by a wavelength converting layer.

Abstract: A semiconductor structure formed on a growth substrate and including a light emitting layer disposed between an n-type region and a p-type region is attached to a carrier by a connection that supports the semiconductor structure sufficiently to permit removal of the growth substrate. In some embodiments, the semiconductor structure is a flip chip device. The semiconductor structure may be attached to the carrier by, for example, a metal bond that supports almost the entire lateral extent of the semiconductor structure, or by interconnects such as solder or gold stud bumps. An underfill material which supports the semiconductor structure is introduced in any spaces between the interconnects. The underfill material may be a liquid that is cured to form a rigid structure. The growth substrate may then be removed without causing damage to the semiconductor structure.

Abstract: A light emitting device includes a structure with a light emitting region disposed between an n-type region and a p-type region. A plurality of holes in the structure, which form a photonic crystal, are formed in a first region of the structure corresponding to a first portion of the light emitting region. A second region of the structure corresponding to a second portion of the light emitting region is free of holes. The device is configured such that when forward biased, current is injected in the second region and the first region is substantially free of current.

Abstract: A photonic crystal structure is formed in an n-type region of a III-nitride semiconductor structure including an active region sandwiched between an n-type region and a p-type region. A reflector is formed on a surface of the p-type region opposite the active region. In some embodiments, the growth substrate on which the n-type region, active region, and p-type region are grown is removed, in order to facilitate forming the photonic crystal in an n-type region of the device, and to facilitate forming the reflector on a surface of the p-type region underlying the photonic crystal. The photonic crystal and reflector form a resonant cavity, which may allow control of light emitted by the active region.

Abstract: A photonic crystal light emitting diode (“PXLED”) is provided. The PXLED includes a periodic structure, such as a lattice of holes, formed in the semiconductor layers of an LED. The parameters of the periodic structure are such that the energy of the photons, emitted by the PXLED, lies close to a band edge of the band structure of the periodic structure. Metal electrode layers have a strong influence on the efficiency of the PXLEDs. Also, PXLEDs formed from GaN have a low surface recombination velocity and hence a high efficiency. The PXLEDs are formed with novel fabrication techniques, such as the epitaxial lateral overgrowth technique over a patterned masking layer, yielding semiconductor layers with low defect density. Inverting the PXLED to expose the pattern of the masking layer or using the Talbot effect to create an aligned second patterned masking layer allows the formation of PXLEDs with low defect density.

Abstract: Structures are incorporated into a semiconductor light emitting device which may increase the extraction of light emitted at glancing incidence angles. In some embodiments, the device includes a low index material that directs light away from the metal contacts by total internal reflection. In some embodiments, the device includes extraction features such as cavities in the semiconductor structure which may extract glancing angle light directly, or direct the glancing angle light into smaller incidence angles which are more easily extracted from the device.

Abstract: A semiconductor structure comprising a III-nitride light emitting layer disposed between an n-type region and a p-type region is grown over a porous III-nitride region. A III-nitride layer comprising InN is disposed between the light emitting layer and the porous III-nitride region. Since the III-nitride layer comprising InN is grown on the porous region, the III-nitride layer comprising InN may be at least partially relaxed, i.e. the III-nitride layer comprising InN may have an in-plane lattice constant larger than an in-plane lattice constant of a conventional GaN layer grown on sapphire.

Abstract: A photonic crystal structure is formed in an n-type region of a III-nitride semiconductor structure including an active region sandwiched between an n-type region and a p-type region. A reflector is formed on a surface of the p-type region opposite the active region. In some embodiments, the growth substrate on which the n-type region, active region, and p-type region are grown is removed, in order to facilitate forming the photonic crystal in an n-type region of the device, and to facilitate forming the reflector on a surface of the p-type region underlying the photonic crystal. The photonic crystal and reflector form a resonant cavity, which may allow control of light emitted by the active region.

Abstract: A semiconductor light emitting device includes a photonic crystal structure that is a lattice of holes in the semiconductor layers. The photonic crystal structure includes multiple lattices. In some embodiments, the device includes a first lattice formed on a first region of the semiconductor layers and a second lattice formed on a second region of the semiconductor layers. The parameters of the first lattice may be selected to maximize the total radiated power from the device. The parameters of the second lattice may be selected to maximize the light extraction into a 30° cone on a surface of the stack.

Abstract: A photonic crystal structure is formed in an n-type region of a III-nitride semiconductor structure including an active region sandwiched between an n-type region and a p-type region. A reflector is formed on a surface of the p-type region opposite the active region. In some embodiments, the growth substrate on which the n-type region, active region, and p-type region are grown is removed, in order to facilitate forming the photonic crystal in an an-type region of the device, and to facilitate forming the reflector on a surface of the p-type region underlying the photonic crystal. The photonic crystal and reflector form a resonant cavity, which may allow control of light emitted by the active region.

Abstract: A photonic crystal structure is formed in an n-type layer of a III-nitride light emitting device. In some embodiments, the photonic crystal n-type layer is formed on a tunnel junction. The device includes a first layer of first conductivity type, a first layer of second conductivity type, and an active region separating the first layer of first conductivity type from the first layer of second conductivity type. The tunnel junction includes a second layer of first conductivity type and a second layer of second conductivity type and separates the first layer of first conductivity type from a third layer of first conductivity type. A photonic crystal structure is formed in the third layer of first conductivity type.

Abstract: A photonic crystal light emitting diode (“PXLED”) is provided. The PXLED includes a periodic structure, such as a lattice of holes, formed in the semiconductor layers of an LED. The parameters of the periodic structure are such that the energy of the photons, emitted by the PXLED, lies close to a band edge of the band structure of the periodic structure. Metal electrode layers have a strong influence on the efficiency of the PXLEDs. Also, PXLEDs formed from GaN have a low surface recombination velocity and hence a high efficiency. The PXLEDs are formed with novel fabrication techniques, such as the epitaxial lateral overgrowth technique over a patterned masking layer, yielding semiconductor layers with low defect density. Inverting the PXLED to expose the pattern of the masking layer or using the Talbot effect to create an aligned second patterned masking layer allows the formation of PXLEDs with low defect density.

Abstract: A photonic crystal structure is formed in an n-type layer of a III-nitride light emitting device. In some embodiments, the photonic crystal n-type layer is formed on a tunnel junction. The device includes a first layer of first conductivity type, a first layer of second conductivity type, and an active region separating the first layer of first conductivity type from the first layer of second conductivity type. The tunnel junction includes a second layer of first conductivity type and a second layer of second conductivity type and separates the first layer of first conductivity type from a third layer of first conductivity type. A photonic crystal structure is formed in the third layer of first conductivity type.

Abstract: Heterostructure designs are disclosed that may increase the number of charge carriers available in the quantum well layers of the active region of III-nitride light emitting devices such as light emitting diodes. In a first embodiment, a reservoir layer is included with a barrier layer and quantum well layer in the active region of a light emitting device. In some embodiments, the reservoir layer is thicker than the barrier layer and quantum well layer, and has a greater indium composition than the barrier layer and a smaller indium composition than the quantum well layer. In some embodiments, the reservoir layer is graded. In a second embodiment, the active region of a light emitting device is a superlattice of alternating quantum well layers and barrier layers. In some embodiments, the barrier layers are thin such that charge carriers can tunnel between quantum well layers through a barrier layer.

Abstract: A high performance, highly reflective ohmic contact, in the visible spectrum (400 nm–750 nm), has the following multi-layer metal profile. A uniform and thin ohmic contact material is deposited and optionally alloyed to the semiconductor surface. A thick reflector layer selected from a group that includes Al, Cu, Au, Rh, Pd, Ag and any multi-layer combinations is deposited over the ohmic contact material.

Abstract: A semiconductor light emitting device includes an n-type region, a p-type region, and light emitting region disposed between the n- and p-type regions. The n-type, p-type, and light emitting regions form a cavity having a top surface and a bottom surface. Both the top surface and the bottom surface of the cavity may have a rough surface. For example, the surface may have a plurality of peaks separated by a plurality of valleys. In some embodiments, the thickness of the cavity is kept constant by incorporating an etch-stop layer into the device, then thinning the layers of the device by a process that terminates on the etch-stop layer.

Abstract: A III-nitride device includes a first n-type layer, a first p-type layer, and an active region separating the first p-type layer and the first n-type layer. The device may include a second n-type layer and a tunnel junction separating the first and second n-type layers. First and second contacts are electrically connected to the first and second n-type layers. The first and second contacts are formed from the same material, a material with a reflectivity to light emitted by the active region greater than 75%. The device may include a textured layer disposed between the second n-type layer and the second contact or formed on a surface of a growth substrate opposite the device layers.

Abstract: The present invention is an inverted III-nitride light-emitting device (LED) with enhanced total light generating capability. A large area device has an n-electrode that interposes the p-electrode metallization to provide low series resistance. The p-electrode metallization is opaque, highly reflective, and provides excellent current spreading. The p-electrode at the peak emission wavelength of the LED active region absorbs less than 25% of incident light per pass. A submount may be used to provide electrical and thermal connection between the LED die and the package. The submount material may be Si to provide electronic functionality such as voltage-compliance limiting operation. The entire device, including the LED-submount interface, is designed for low thermal resistance to allow for high current density operation. Finally, the device may include a high-refractive-index (n>1.8) superstrate.

Abstract: An inverted III-nitride light-emitting device (LED) with highly reflective ohmic contacts includes n- and p-electrode metallizations that are opaque, highly reflective, and provide excellent current spreading. The n- and p-electrodes each absorb less than 25% of incident light per pass at the peak emission wavelength of the LED active region.