Abstract: In photonic integrated circuits (PICs) having at least one active semiconductor device, such as, a buried heterostructure semiconductor laser, LED, modulator, photodiode, heterojunction bipolar transistor, field effect transistor or other active device, a plurality of semiconductor layers are formed on a substrate with one of the layers being an active region. A current channel is formed through this active region defined by current blocking layers formed on adjacent sides of a designated active region channel where the blocking layers substantially confine the current through the channel. The blocking layers are characterized by being an aluminum-containing Group III-V compound, i.e., an Al-III-V layer, intentionally doped with oxygen from an oxide source. Also, wet oxide process or a deposited oxide source may be used to laterally form a native oxide of the Al-III-V layer.

Abstract: A method of manufacturing a ridge type semiconductor light emitting device includes: a process of epitaxially growing a multi-layered semiconductor layer having at least a first conductive type cladding layer, an active layer, a second conductive type first cladding layer, an etching stop layer, and a second conductive type second cladding layer on a substrate; a process of forming a ridge groove for forming a ridge; and a process of forming a current-flow barrier layer in the ridge groove. The process of forming ridge grooves has first and second anisotropic etching processes of performing anisotropic etching, an etching-mask forming process, and an isotropic etching process of performing anisotropic etching.

Abstract: A structure of a gallium nitride light emitting diode has a transparent conductive window layer including a diffusion barrier layer, an ohmic contact layer, and a window layer. By using the added domain contact layer, the diffusion barrier layer and the P-type semiconductor layer of the light emitting diode are put into ohmic contact. And then, the rising of the contact resistivity is barred by applying the diffusion barrier layer to block the diffusion of the window layer from the contact with the domain contact layer so as to lower down the operating voltage and advance the transparency.

Abstract: A light emitting device and a method of manufacturing the same are provided. A light emitting device has a structure wherein a substrate, an n-type clad layer, a light emitting layer, a p-type clad layer, an ohmic contact layer, and a reflective layer are successively stacked. The ohmic contact layer is formed by adding an additional element to an indium oxide. According to the light emitting device and the method of manufacturing the same, the characteristics of ohmic contact with a p-type clad layer is improved, thus increasing the efficiency and yield of wire bonding during packaging FCLEDS. Also, it is possible to increase the light emitting efficiency and life span of light emitting devices due to the low contactless resistance and the excellent electric current and voltage characteristic.

Abstract: Although there is provided a high light transmittance of an emitted light by a ITO electrode film conventionally employed, there occurs a formation of a Schottky type contact between the ITO electrode film and a p type GaN system semiconductor layer, thus resulting in a not uniform flow of an electric current. It is an object of the present invention to provide a semiconductor light emitting device constituted by forming a transparent electrode, which facilitates acquiring an ohmic property, to be replaced by an ITO electrode film, at the light extracting or light exit side of the GaN system semiconductor light emitting device, so as to improve a light emission efficiency and a radiation extracting efficiency or a light exit efficiency of a GaN system semiconductor light emitting device.

Abstract: A liquid crystal display (LCD) device having non-white and white light emitting diodes and a liquid crystal display. A spectrum converting material is positioned between non-white LEDs and the LCD to convert the non-white light from the LEDs toward a white light spectrum. The liquid crystal display may include a plurality of light emitting diodes, a light pipe, and a spectrum converting material. The spectrum converting material may be a phosphorized material located between the plurality of non-white light emitting diodes and the light pipe. A light extracting surface may be located near a first surface of the light pipe, a diffuser located near a second side of the light pipe, where the first and second sides are opposite sides of the light pipe, a reflective polarizer, and an liquid crystal display. The light from the light pipe may passes through the diffuser, the reflective polarizer, before backlighting the liquid crystal display. The non-white LEDs may include blue LED, ultraviolet LEDs, and the like.

Abstract: A nitride based 3-5 group compound semiconductor light emitting device comprising: a substrate; a buffer layer formed above the substrate; a first In-doped GaN layer formed above the buffer layer; an InxGa1—xN/InyGa1?yN super lattice structure layer formed above the first In-doped GaN layer; a first electrode contact layer formed above the InxGa1—xN/InyGa1?yN super lattice structure layer; an active layer formed above the first electrode contact layer and functioning to emit light; a second In-doped GaN layer; a GaN layer formed above the second In-doped GaN layer; and a second electrode contact layer formed above the GaN layer. The present invention can reduce crystal defects of the nitride based 3-5 group compound semiconductor light emitting device and improve the crystallinity of a GaN GaN based single crystal layer in order to improve the performance of the light emitting device and ensure the reliability thereof.

Abstract: Provided are a nitride-based light emitting device using a p-type conductive transparent thin film electrode layer and a method of manufacturing the same. The nitride-based light emitting device includes a substrate, and an n-cladding layer, an active layer, a p-cladding layer and an ohmic contact layer sequentially formed on the substrate. The ohmic contact layer is made from a p-type conductive transparent oxide thin film. The nitride-based light emitting device and method of manufacturing the same provide excellent I-V characteristics by improving characteristics of an ohmic contact to a p-cladding layer while enhancing light emission efficiency of the device due to high light transmittance exhibited by a transparent electrode.

Abstract: A GaN layer is formed on a sapphire substrate through an AlN buffer layer and doped with Mg to prepare a laminate (referred to as “GaN substrate”). A metal (Pt and Ni) electrode 50 nm thick is formed on the GaN substrate by (1) vapor deposition after the GaN substrate is heated to a temperature of 300° C. or by (2) vapor deposition while the GaN substrate is left at room temperature. (3) The electrode obtained in (2) is heated to 300° C. in a nitrogen atmosphere. The contact resistance of the electrode obtained in (1) is lower by two or three digits than that of the electrode obtained in (2) or (3). That is, the electric characteristic of the electrode obtained in (1) is improved greatly.

Abstract: A nitride compound semiconductor element having improved characteristics, productivity and yield. A nitride compound semiconductor element includes: a sapphire substrate; a first single crystalline layer of AlN formed on said sapphire substrate; a second single crystalline layer formed on said first single crystalline layer, said second single crystalline layer being made of AlxGa1-xN (0.8?x?0.97) and having a thickness of equal to or more than 0.3 ?m and equal to or less than 6 ?m; and a device structure section of a nitride semiconductor formed on said second single crystalline layer.

Abstract: An optical modulator comprises a first waveguide layer and a barrier layer, and a quantum well layer sandwiched between the first waveguide layer and the barrier layer, where the quantum well layer has a graded composition that varies the bandgap energy of the quantum well layer between a minimum bandgap energy and the bandgap energy of at least one of the first waveguide layer and the barrier layer.

Abstract: When a semiconductor light emitting device or a semiconductor device is manufactured by growing nitride III-V compound semiconductor layers, which will form a light emitting device structure or a device structure, on a nitride III-V compound semiconductor substrate composed of a first region in form of a crystal having a first average dislocation density and a plurality of second regions having a second average dislocation density higher than the first average dislocation density and periodically aligned in the first region, device regions are defined on the nitride III-V compound semiconductor substrate such that the device regions do not substantially include second regions, emission regions or active regions of devices finally obtained do not include second regions.

Abstract: A semiconductor light-emitting device is made of a group III-nitride compound semiconductor expressed as AlxGayIn1?x?yN (where 0?x?1, 0?y?1, and 0?x+y?1). The semiconductor light-emitting device includes: a substrate made of SiC; a semiconductor layer which is placed above the substrate and has a light-emitting region; a multi-layered reflective layer which is placed between the substrate and the semiconductor layer and which reflects light produced in the light-emitting region; and a phase matching layer which is placed between the substrate and the multi-layered reflective layer and which reflects light produced in the light-emitting region and matches a phase of light reflected from a lower boundary surface of the multi-layered reflective layer and a phase of light reflected from a lower boundary surface of the substrate among light produced in the light-emitting region.

Abstract: A nitride semiconductor light emitting device including a light emitting diode and a diode formed on a single substrate, in which the light emitting diode and the diode use a common electrode. According to the present invention, an active layer and a p-type nitride semiconductor layer are each divided into a first region and a second region by an insulative isolation layer, and an ohmic contact layer is formed on the p-type nitride semiconductor layer contained in the first region. A p-type electrode is formed on the ohmic contact layer and is extended to the p-type nitride semiconductor layer contained in the second region. An n-type electrode is formed on the p-type nitride semiconductor layer contained in the second region, passes through the p-type nitride semiconductor layer and the active layer contained in the second region, and is connected to the first n-type nitride semiconductor layer.

Abstract: An electronic device includes a conductive n-type substrate, a Group III nitride active region, an n-type Group III-nitride layer in vertical relationship to the substrate and the active layer, at least one p-type layer, and means for providing a non-rectifying conductive path between the p-type layer and the n-type layer or the substrate. The non-rectifying conduction means may include a degenerate junction structure or a patterned metal layer.

Abstract: The nitride-based semiconductor light-emitting device and manufacturing method thereof are disclosed: the nitride-based semiconductor light-emitting device includes a reflective layer formed on a support substrate, a p-type nitride-based semiconductor layer, a light-emitting layer and an n-type nitride-based semiconductor layer successively formed on the reflective layer, wherein irregularities are formed on a light extracting surface located above the n-type nitride-based semiconductor layer.

Abstract: A surface emitting semiconductor laser includes: a semiconductor substrate; a first semiconductor multilayer reflection film of a first conduction type on the semiconductor substrate; a second semiconductor multilayer reflection film of a second conduction type; an active region and a current confining layer interposed between the first and second semiconductor multilayer reflection films; and a low-resistance layer interposed between the current confining layer and the active region.

Abstract: A GaN LED structure with a short period superlattice contacting layer is provided. The LED structure comprises, from the bottom to top, a substrate, a double buffer layer, an n-type GaN layer, a short period superlattice contacting layer, an active layer, a p-type shielding layer, and a contacting layer. The feature is to avoid the cracks or pin holes in the thick n-type GaN layer caused during the fabrication of heavily doped (n>1×1019 cm?3) thick n-type GaN contacting layer, so that the quality of the GaN contacting layer is assured. In addition, by using short period heavily silicon doped Al1-x-yGaxInyN (n++-Al1-x-yGaxInyN) to grow a superlattice structure to become a short period superlattice contacting layer structure, which is used as a low resistive n-type contacting layer in a GaInN/GaN MQW LED. In the following steps, it is easier to form an n-type ohmic contacting layer, and the overall electrical characteristics are improved.

Abstract: The invention relates to a nitride semiconductor LED and a fabrication method thereof. In the LED, a first nitride semiconductor layer, an active region a second nitride semiconductor layer of a light emitting structure are formed in their order on a transparent substrate. A dielectric mirror layer is formed on the underside of the substrate, and has at least a pair of alternating first dielectric film of a first refractivity and a second dielectric film of a second refractivity larger than the first refractivity. A lateral insulation layer is formed on the side of the substrate and the light emitting structure. The LED of the invention effectively collimate undesirably-directed light rays, which may be otherwise extinguished, to maximize luminous efficiency, and are protected by the dielectric mirror layer formed on the side thereof to remarkably improve ESD characteristics.

Abstract: A light emitting diode and a method of the same are provided. The light emitting diode includes a light-emitting structure, a silicon substrate and a bonding layer. The light-emitting structure includes two semiconductor layers of different doped types. The light-emitting structure is capable of emitting light when a current passes through. The silicon substrate includes two zones of different doped types. The bonding layer is interposed between the light-emitting structure and the silicon substrate so that the semiconductor layer and the zone closest to the bonding layer are of different doped types.

Abstract: The invention is directed to a vertically emitting laser and a method of manufacturing such a laser having a current aperture and a semiconductor relief. The semiconductor relief and the current aperture are defined in the same processing operation, thereby causing the semiconductor relief and the current aperture to be substantially self-aligned with respect to one another. In addition, such processing results in an area ratio of the semiconductor relief and the current aperture to be substantially self-scaling with respect to processing variations.

Abstract: AlGaInP system laser device (24) and AlGaAs system laser device (26) are arranged so that respective stripes (28, 30) are parallel to each other. The AlGaInP system laser device (24) is placed to (011) plane (22b) side from the centerline of the substrate and the AlGaAs system laser device (26) is placed to the (0{overscore (1)}{overscore (1)}) plane (22a) side from the centerline of the substrate when viewed from the main emitting plane (01{overscore (1)}) (22c) side of laser light. Substrate (22) is an off substrate and inclines from the (0{overscore (1)}{overscore (1)}) plane (22a) toward the (011) plane (22b) with respect to the (100) plane at a certain angle (? off) within the range of 2 degrees and 15 degrees. Optical axis L1 of the AlGaInP system laser device (24) is parallel to optical axis L2 of the AlGaAs system laser device (26) and approaches at an angle of about 0.5 degrees.

Abstract: The invention provides a semiconductor light emitting device and the method of making it. The semiconductor light emitting device, according to the invention, includes an undoped InxGAyAl2N film, as an Ohmic layer, formed between a top-most semiconductor material layer and a transparent conductive oxide layer. Since the undoped film as a tunneling layer is very thin (?20 angstroms), the electric field across the tunneling layer, under forward bias, will make electron tunneling from valence band to conduction band, and return to the transparent conductive layer, A reasonably low and stable forward voltage of the semiconductor light emitting device according to the invention can be achieved.

Abstract: A gallium nitride-based semiconductor light-emitting device includes a sapphire substrate having a nitridated upper surface; a polarity conversion layer formed on the sapphire substrate and made of MgN-based single ciystals; a first conductive gallium nitride-based semiconductor layer formed on the polarity conversion layer; an active layer formed on the first conductive gallium nitride-based semiconductor layer; and a second conductive gallium nitride-based semiconductor layer formed on the active layer.

Abstract: A semiconductor light emitting device is fabricated by forming a mask having an opening on a substrate, forming a crystal layer having a tilt crystal plane tilted from the principal plane of the substrate by selective growth from the opening of the mask, and forming, on the crystal layer, a first conductive type layer, an active layer, and a second conductive type layer, which extend within planes parallel to the tilt crystal plane, and removing the mask. The semiconductor light emitting device can be fabricated without increasing fabrication steps while suppressing threading dislocations extending from the substrate side and keeping a desirable crystallinity. The semiconductor light emitting device is also advantageous in that since deposition of polycrystal on the mask is eliminated, an electrode can be easily formed, and that the device structure can be finely cut into chips.

Abstract: Affords semiconductor light-emitting devices in which generation of spontaneous electric fields in the active layer is reduced to enable enhanced brightness. Semiconductor light-emitting device (1) is furnished with an n-type cladding layer (3), a p-type cladding layer (7) provided over the n-type cladding layer (3), and an active layer (5) composed of a nitride and provided in between the n-type cladding layer (3) and the p-type cladding layer (7), and therein is characterized in that the angle formed by an axis orthogonal to the interface between the n-type cladding layer (3) and the active layer (5), and the c-axis in the active layer (5), and the angle formed by an axis orthogonal to the interface between the active layer (5) and the p-type cladding layer (7), and the c-axis in the active layer (5), are each greater than zero.

Abstract: In photonic integrated circuits (PICs) having at least one active semiconductor device, such as, a buried heterostructure semiconductor laser, LED, modulator, photodiode, heterojunction bipolar transistor, field effect transistor or other active device, a plurality of semiconductor layers are formed on a substrate with one of the layers being an active region. A current channel is formed through this active region defined by current blocking layers formed on adjacent sides of a designated active region channel where the blocking layers substantially confine the current through the channel. The blocking layers are characterized by being an aluminum-containing Group III-V compound, i.e., an Al-III-V layer, intentionally doped with oxygen from an oxide source. Also, wet oxide process or a deposited oxide source may be used to laterally form a native oxide of the Al-III-V layer.

Abstract: A nitride-based laser diode structure utilizing a single GaN:Mg waveguide/cladding layer, in place of separate GaN:Mg waveguide and AlGaN:Mg cladding layers used in conventional nitride-based laser diode structures. When formed using an optimal thickness, the GaN:Mg layer produces an optical confinement that is comparable to or better than conventional structures. A thin AlGaN tunnel barrier layer is provided between the multiple quantum well and a lower portion of the GaN:Mg waveguide layer, which suppresses electron leakage without any significant decrease in optical confinement. A split-metal electrode is formed on the GaN:Mg upper waveguide structure to avoid absorption losses in the upper electrode metal. A pair of AlGaN:Si current blocking layer sections are located below the split-metal electrode sections, and separated by a gap located over the active region of the multiple quantum well.

Abstract: A flip chip light emitting diode die (10, 10?, 10?) includes a light-transmissive substrate (12, 12?, 12?) and semiconductor layers (14, 14?, 14?) that are selectively patterned to define a device mesa (30, 30?, 30?). A reflective electrode (34, 34?, 34?) is disposed on the device mesa (30, 30?, 30?). The reflective electrode (34, 34?, 34?) includes a light-transmissive insulating grid (42, 42?, 60, 80) disposed over the device mesa (30, 30?, 30?), an ohmic material (44, 44?, 44?, 62) disposed at openings of the insulating grid (42, 42?, 60, 80) and making ohmic contact with the device mesa (30, 30?, 30?), and an electrically conductive reflective film (46, 46?, 46?) disposed over the insulating grid (42, 42?, 60, 80) and the ohmic material (44, 44?, 44?, 62). The electrically conductive reflective film (46, 46?, 46?) electrically communicates with the ohmic material (44, 44?, 44?, 62).

Abstract: A nitride semiconductor light-emitting device includes a first conductive nitride semiconductor layer; an active layer formed on the first conductive nitride semiconductor layer, and having at least one quantum well layer and at least one quantum barrier layer alternatively laminated; and a second conductive nitride semiconductor layer formed on the active layer, wherein at least one of the quantum well layer and quantum barrier layer in the active layer is doped with elemental Al in a concentration of less than 1%.

Abstract: A semiconductor laminating portion including a light emitting layer forming portion having at least an n-type layer and a p-type layer is formed on a semiconductor substrate. A current blocking layer is partially formed on its surface while a current diffusing electrode is formed on the entire surface thereof. The current diffusing electrode is patterned into a plurality of light emitting unit portions (A), electrode pad portion (B), and connecting portions (C) for connecting between the electrode pad portion (B) and the light emitting unit portions (A) or between two of the light emitting unit portions (A), and a part of the semiconductor laminating portion may be etched according to the patterning of the current diffusing electrode. The bonding electrode may be formed on the electrode pad portion (B) which is formed so as to make the light emitting layer forming portion non-luminous.

Abstract: A semiconductor optical device such as a laser or semiconductor optical amplifier (SOA) based on an indium phosphide substrate or equivalent buffer layer. The active layer of the device is based on conventional InGaAs(P) alloy, but additionally includes N in order to increase the operating wavelength to greater than 1.5 ?m, preferably to a wavelength lying in the C- or L-band. The active layer composition may thus be denoted In1-xGaxAsyNzPp with x?0.48, y?1?z?p, z?0.05, p?0. The active layer may include a quantum well or multi-quantum wells in which case its thickness is preferably less than the critical thickness for lattice relaxation. In other embodiments the active layer is a “massive” layer with quasi-bulk properties. The active layer may advantageously be under tensile stress, preferably roughly between 1% and 2.2%, to manipulate the light and heavy hole bands. The active layer is typically bounded by barrier layers made of a suitable semiconductor alloy, such as AlInAs or InGaAs(P).

Abstract: A high-efficiency light emitting diode is provided. The light emitting diode includes a substrate; a first compound semiconductor layer formed on the top surface of the substrate; a first electrode formed on a region of the first compound semiconductor layer; an active layer formed on a region of the first compound semiconductor layer excluding the region with the first electrode layer, in which 430-nm or less wavelength light is generated; a second compound semiconductor layer formed on the active layer; and a second electrode formed on the second compound semiconductor layer, with a filling ratio of 20–80% with respect to the area of the top surface of the substrate. The light emission of a 430-nm or less light emitting diode can be enhanced by adjusting the size of the p-type second electrode within the range of 20–80%.

Abstract: A high luminance indium gallium aluminum nitride light emitting diode (LED) is disclosed, including a substrate, a first conductive type nitride layer, an active layer, a second conductive type nitride layer, a first contact layer, a second contact layer, and a conductive transparent layer. The first contact layer has a first bandgap and a first doping concentration, and is disposed on the second conductive type nitride layer. The second contact layer has a second bandgap and a second doping concentration, and is disposed on the first contact layer. The first doping concentration and the second doping concentration are respectively larger than a predetermined concentration, and the first bandgap is smaller than the second bandgap. The second contact layer is thinner than a predetermined thickness so that a tunneling effect occurs between the conductive transparent layer and the second contact layer while the LED is in operation.

Abstract: An active semiconductor device, such as, buried heterostructure semiconductor lasers, LEDs, modulators, photodiodes, heterojunction bipolar transistors, field effect transistors or other active devices, comprise a plurality of semiconductor layers formed on a substrate with one of the layers being an active region. A current channel is formed through this active region defined by current blocking layers formed on adjacent sides of a designated active region channel where the blocking layers substantially confine the current through the channel. The blocking layers are characterized by being an aluminum-containing Group III–V compound, i.e., an Al-III–V layer, intentionally doped with oxygen from an oxide source. Also, wet oxide process or a deposited oxide source may be used to laterally form a native oxide of the Al-III–V layer. An example of a material system for this invention useful at optical telecommunication wavelengths is InGaAsP/InP where the Al-III–V layer comprises InAlAs:O or InAlAs:O:Fe.

Abstract: In this semiconductor laser device, an InGaP etching block layer 11 as an etching selection layer having etching selectivity for an n-type AlInP current block layer 10, which is a non-optical-absorption layer, is formed on the n-type current block layer 10. Since this etching block layer 11 prevents the current block layer 10 on both sides of a ridge 20 from being etched during manufacture, a contact layer 12 can be prevented from entering gaps between the sides of this ridge 20 and the current block layer 10. Therefore, light oscillating in an active layer 4 is taken out from a device end surface without being absorbed in the contact layer 12. According to this semiconductor laser device, an oscillation threshold current and an operation current can be maintained low, deterioration of differential quantum efficiency can be prevented and reliability can be improved.

Abstract: A method and a multijunction solar device having a high band gap heterojunction middle solar cell are disclosed. In one embodiment, a triple-junction solar device includes bottom, middle, and top cells. The bottom cell has a germanium (Ge) substrate and a buffer layer, wherein the buffer layer is disposed over the Ge substrate. The middle cell contains a heterojunction structure, which further includes an emitter layer and a base layer that are disposed over the bottom cell. The top cell contains an emitter layer and a base layer disposed over the middle cell.

Abstract: A III group nitride system compound semiconductor light emitting element has: a transparent substrate that is of a material except for III group nitride system compound semiconductor; a convex light trapping member that is formed directly or through a buffer layer on the surface of the transparent substrate; and a III group nitride system compound semiconductor layer that is formed on the surface of the transparent substrate. The light trapping member has a refractive index substantially equal to that of the transparent substrate or closer to that of the transparent substrate than that of the III group nitride system compound semiconductor layer.

Abstract: On a substrate made of e.g., sapphire single crystal is formed an Al underlayer having FWHM X-ray rocking curve value of 90 seconds or below. A buffer layer is formed on the AlN underlayer and has a composition of AlpGaqIn1?p?qN (0?p?1, 0?y?q). A GaN-based semiconductor layer group is formed on the buffer layer.

Abstract: A light emitting diode includes a transparent substrate and a GaN buffer layer on the transparent substrate. An n-GaN layer is formed on the buffer layer. An active layer is formed on the n-GaN layer. A p-GaN layer is formed on the active layer. A p-electrode is formed on the p-GaN layer and an n-electrode is formed on the n-GaN layer. A reflective layer is formed on a second side of the transparent substrate. Also, a cladding layer of AlGaN is between the p-GaN layer and the active layer.

Abstract: Light emitting devices with improved light extraction efficiency are provided. The light emitting devices have a stack of layers including semiconductor layers comprising an active region. The stack is bonded to a transparent optical element having a refractive index for light emitted by the active region preferably greater than about 1.5, more preferably greater than about 1.8. A method of bonding a transparent optical element (e.g., a lens or an optical concentrator) to a light emitting device comprising an active region includes elevating a temperature of the optical element and the stack and applying a pressure to press the optical element and the light emitting device together. A block of optical element material may be bonded to the light emitting device and then shaped into an optical element. Bonding a high refractive index optical element to a light emitting device improves the light extraction efficiency of the light emitting device by reducing loss due to total internal reflection.

Abstract: The present invention provides a nitride semiconductor device comprising an active layer of a quantum well structure, a first conductive clad layer and a second conductive clad layer. The first conductive clad layer is made of the quaternary nitride semiconductor InAlGaN having a lattice constant equal to or larger than that of the active layer and includes a first nitride semiconductor layer having an energy band gap larger than that of the active layer, a second nitride semiconductor layer having an energy band gap smaller than that of the first nitride semiconductor layer and a third nitride semiconductor layer having an energy band gap larger than that of the second nitride semiconductor layer, sequentially closer to the active layer.

Abstract: A compound semiconductor laser of a III group nitride semiconductor of the present invention includes a first cladding layer 104 of a first conduction type formed on a substrate 101, an active layer 106 formed on the first cladding layer, a second cladding layer 108 of a second conduction type formed on the active layer 106, and a buried layer 110 formed on the second cladding layer 108, the buried layer having an opening portion for constricting a current in a selected region of the active layer, wherein an upper portion of the second cladding layer 108 has a ridge portion, the ridge portion residing in the opening portion of the buried layer 110, and the buried layer 110 does not substantially absorb light output from the active layer 106, and the buried layer has a refractive index which is approximately identical with that of the second cladding layer 108.

Abstract: A GaN LED structure with a short period superlattice digital contacting layer is provided. The LED structure comprises, from the bottom to top, a substrate, a double buffer layer, an n-type GaN layer, a short period superlattice digital contacting layer, an active layer, a p-type shielding layer, and a contacting layer. The feature is to avoid the cracks or pin holes in the thick n-type GaN layer caused during the fabrication of heavily doped (n>1×1019cm?3) thick n-type GaN contacting layer, so that the quality of the GaN contacting layer is assured. In addition, by using short period heavily doped silicon Al1-x-yGaxInyN (n++-Al1-x-yGaxInyN) to grow a superlattice structure to become a short period superlattice digital contacting layer structure, which is used as a low resistive n-type contacting layer in a GaInN/GaN MQW LED. In the following steps, it is easier to form an n-type ohmic contacting layer, and the overall electrical characteristics are improved.

Abstract: A structure for the n-type contact layer in the GaN-based MQW LEDs is provided. Instead of using Si-doped GaN as commonly found in conventional GaN-based MQW LEDs, the n-type contact layer provided by the present invention achieves high doping density (>1×1019 cm?3) and low resistivity through a superlattice structure combining two types of materials, AlmInnGa1-m-nN and AlpInqGa1-p-qN (0?m,n<1, 0<p,q<1, p+q?1, m<p), each having its specific composition and doping density. In addition, by controlling the composition of Al, In, and Ga in the two materials, the n-type contact layer would have a compatible lattice constant with the substrate and the epitaxial structure of the GaN-based MQW LEDs. This n-type contact layer, therefore, would not chap from the heavy Si doping, have a superior quality, and reduce the difficulties of forming n-type ohmic contact electrode. In turn, the GaN-based MQW LEDs would require a lower operation voltage.

Abstract: A light emitting layer forming portion is provided on a semiconductor substrate, in which an active layer made of a compound semiconductor is sandwiched between a first and second clad layers made of compound semiconductor having band gap greater than that of the active layer, respectively and having a different conductivity type each other and furthermore a window layer is provided above the second clad layer. The second clad layer is made of a semiconductor having refractive index greater than that of the first clad layer. More preferably the window layer is made of a semiconductor having a refractive index greater than that of the second clad layer. As a result, the absorption of the light emitted from the light emitting layer in the semiconductor substrate can be reduced, and the light can be attracted toward the top surface so that the external quantum efficiency can be advanced.

Abstract: An AlGaAs-based semiconductor laser 29 is formed on an n-type GaAs substrate 21 and thereafter etching is carried out until reaching an n-type AlGaAs clad layer 23 from the surface. Next, the n-type AlGaAs clad layer 23 is removed by etching with an etchant having selectivity to GaAs. Subsequently, the surface of an n-type GaAs buffer layer 22 is lightly etched. Thus, the n-type GaAs buffer layer 22 of the AlGaAs-based semiconductor laser 29 is left in a slightly abraded state on the n-type GaAs substrate 21, maintaining the flatness of the groundwork layer during growing an AlGaInP-based semiconductor laser 38 at the second time. Therefore, the flatness of the crystals of, in particular, an active layer grown at the second time can be improved, and the poor characteristics of the AlGaInP-based semiconductor laser 38 attributed to the poor flatness of the groundwork can be improved.

Abstract: A Group III nitride compound semiconductor light-emitting device includes a multilayer having a quantum well structure containing an InGaN well layer and an AlGaN barrier layer. The film thickness, growth rate and growth temperature of the InGaN layer as the well layer and the film thickness of the AlGaN layer as the barrier layer are controlled to be optimized to thereby improve an output of the light-emitting device.

Abstract: A light emitting device capable of readily produce a pseudo-continuous spectrum covering a wide wavelength regions at low costs, and of totally solving various problems which have resided in the conventional light sources, and a lighting apparatus using this device is provided. The light emitting device 10 is configured so that an active layer in a double hetero light emitting layer portion composed of compound semiconductors comprises a plurality of emission unit layers differing from each other in band gap energy, and so as to emit a simulatively synthesized light having a pseudo-continuous spectrum ensuring an emission intensity of 5% or more of a peak intensity over a wavelength region of 50 nm or more.

Abstract: The present invention relates to a method of manufacturing a nitride semiconductor, and, more particularly, a crystal growth method of a nitride semiconductor wherein a nitride semiconductor are grown on a nitride buffer layer including aluminums so that it is possible to improve electrical and crystalline characteristics.