Abstract: A multiwavelength LED device including a first LED constructed to emit light of a first wavelength and a second LED constructed to emit light of a second wavelength, different than the first wavelength. The first and second LEDs are stacked vertically on a substrate and positioned to both emit light in the same direction. One of the LEDs is transparent to light emitted by the other of the LEDs so that light from both LEDs is emitted through a single aperture and can be mixed in intensity to produce a variety of wavelengths. The LEDs are individually addressable.

Abstract: Group II-VI compound semiconductor light emitting devices which include at least one II-VI quantum well region of a well layer disposed between first and second barrier layers is disclosed. The quantum well region is sandwiched between first and second cladding layers of a II-VI semiconductor material. The first cladding layer is formed on and lattice matched to the first barrier layer and to a substrate of a III-V compound semiconductor material. The second cladding layer is lattice matched to the second barrier layer. The quantum well layer comprises a II-VI compound semiconductor material having the formula A.sub.x B.sub.(1-x) C wherein A and B are two different elements from Group II and C is at least one element from Group VI. When the second cladding layer has a p-type conductivity, a graded bandgap ohmic contact according to the present invention can be utilized.

Abstract: A semiconductor device having superior light output efficiency is disclosed. A p-Si diffusion layer is formed on a Si substrate and an n-Si diffusion layer is formed in the p-Si diffusion layer. An n-GaAs layer constituting an active region for emitting light is grown on the p-Si diffusion layer and the n-Si diffusion layer of the Si substrate and a p-GaAs layer constituting an active region for emitting light is grown on the n-GaAs layer. An upper electrode is disposed on an upper surface of the p-GaAs layer above the p-Si diffusion layer. Current is injected from the upper electrode through a region of the pn junction between the n-GaAs layer and the p-GaAs layer other than that directly below the upper electrode, and light is emitted from this region. The emitted light passes through the p-GaAs layer to outside the device without passing through and being attenuated by the upper electrode.

Abstract: Light emitting devices are requiring greater switching speeds to achieve greater modulation bandwidths. The problems of intrinsic capacitance associated with conventional semiconductor heterojunction devices are reduced by the reduction of pn junction capacitance as well as the use of a semi-insulating blocking layer and a conductive substrate. Furthermore, a light absorbing layer is disposed on one side of an unetched portion of the semi-insulating material and an active layer disposed on an opposite side of the unetched portion. Also, the interface of the semi-insulating material and the active and absorbing layers are at prescribed angles that reduce back reflections to the absorbing and active layers. This arrangement reduces pumping in the absorbing region and thus reduces the lasing effect, allowing for a stable LED.

Abstract: A quantum well device has an active region adapted to pass a tunneling current of charge carriers and comprising layers of material forming alternating potential barriers and potential wells. The structure defines, in use, a first potential well at one end of the active region, said first potential well defining a first quasi-defined energy level, and to further define second and third quasi-defined energy levels. The relative heights and thicknesses of the potential barriers when the device is in use are structured so that the first quasi-defined energy level has a longer lifetime than the second and third quasi-defined energy levels and there is a degree of coupling between the three quasi-defined energy levels which is strongest between the second and third quasi-defined energy levels. The transmission coefficient through the active region shows a resonance peak at each of the energies of the three quasi-defined energy levels.

Abstract: A light-emitting semiconductor device includes a sapphire substrate whose main surface orientation is tilted by 1 to 4 degrees from its axis "a" <1120>, and layers epitaxially formed thereon. Tilting the surface orientation of the sapphire substrate enables uniform doping of a p-type impurity into the layers epitaxially grown thereon. As a result, the luminous intensity of the light-emitting semiconductor device is improved.

Abstract: The present invention relates to quantum well semiconductor light emitting devices such as lasers that utilize resonant tunneling for carrier injection and spatially-diagonal transitions between an energy state in the conduction band of one quantum well and an energy state in the valence band of the adjacent quantum well for light emission, resulting in much improvement in both radiative efficiency and carrier injection efficiency. An elementary structure of the invented devices comprises two spatially coupled quantum wells residing in conduction and valence bands respectively wherein the valence band-edge in one quantum well is higher than the conduction band-edge of the other quantum well. Each quantum well contains at least one energy state formed by the quantum size effect.

Abstract: A superluminescent diode includes a semiconductor substrate of a first conductivity type. A lower cladding layer of the first conductivity type is provided on the semiconductor substrate. An active layer is provided on the lower cladding layer. An upper cladding layer of a second conductivity type opposite to the first conductivity type is provided on the active layer. A current blocking layer of the first conductivity type is buried in the upper cladding layer. The current blocking layer has a stripe-shaped groove serving as a current-injection region. The current-injection region is formed in a manner that it extends from an end face of a chip to the inside of the chip, and has a length shorter than that of the chip. The current blocking layer is made of a material having a band gap energy not greater than that of the active layer and a refractive index not smaller than that of the active layer so that light advancing in the active layer is absorbable.

Abstract: A light emitting diode (LED) and resistors for varying the light intensity of the LED are formed on a single chip. Each of the LED portion and the resistor portion includes an active layer and a clad layer successively deposited on a substrate of the chip. The substrate may be doped with one of P-type dopant and N-type dopant and the clad layer with the other of P and Y-type dopants. A first and second electrodes are formed on an exposed surface of the substrate and the clad layer of the LED portion respectively. A plurality of resistor electrodes are formed on the clad layer of the resistor portion. It is preferable to have different spacing between the resistor electrodes to form variable resistances.

Abstract: A compound-semiconductor optical device and method. The optical device is provided with one or more asymmetrically-graded heterojunctions between compound semiconductor layers for forming a distributed Bragg reflector mirror having an improved electrical and thermal resistance. Efficient light-emitting devices such as light-emitting diodes, resonant-cavity light-emitting diodes, and vertical-cavity surface-emitting lasers may be formed according to the present invention, which may be applied to the formation of resonant-cavity photodetectors.

Abstract: A light emitting diode includes a first conductivity type GaAs substrate having a second conductivity type region as a current blocking layer. A first conductivity type distributed Bragg reflector layer is formed on the GaAs substrate. An AlGaInP double heterostructure including a lower cladding AlGaInP layer of the first conductivity type, an undoped active AlGaInP layer, and an upper cladding AlGaInP layer of the second conductivity type is grown on top of the distributed Bragg reflector layer. The undoped active AlGaInP layer can also be replaced by a multi-layer quantum well structure of AlGaInP or a strained multi-layer quantum well structure of AlGaInP. A second conductivity type layer of low energy band gap and high conductivity material is formed on the AlGaInP double heterostructure. A GaP window layer of the second conductivity type is then formed on top of the low energy band gap layer.

Abstract: A surface emitting light emitting device with a semiconducting substrate, a semiconducting mirror stack positioned on the substrate surface, a spacer layer positioned on the mirror stack, an active region positioned on the spacer layer, a second spacer layer positioned on the active region, a second semiconducting mirror stack positioned on the second spacer layer, and a top contact layer positioned in contact with the second semiconducting mirror stack. The active region includes multiple quantum wells each having a different transition wavelength and positioned on the spacer layer with the quantum well possessing the longest transition wavelength located closest to the spacer layer and additional quantum wells of the multiple quantum wells positioned in order of decreasing transition wavelength so that the sum of the emission from all of the quantum wells results in a broad and uniform output emission spectrum.

Abstract: A light emitting semiconductor device is provided which comprises a semiconductor chip and a sub-mount assembled with the semiconductor chip. The semiconductor chip includes a light-permeable insulating substrate and a laminate of semiconductor layers formed on a support surface of the insulating substrate for generating light to be emitted from a tail surface of the substrate. The sub-mount includes an electrically conductive substrate having a mounting surface facing the support surface of the insulating substrate. The mounting surface of the conductive substrate is formed with at least one auxiliary anode electrode which is electrically connected to the conductive substrate and an anode electrode of the semiconductor chip. The mounting surface of the conductive substrate is also formed with at least one auxiliary cathode electrode which is insulated from the conductive substrate but electrically connected to a cathode electrode of the semiconductor chip.

Abstract: In a light emitting device made of a group II-VI semiconductor, a P-type interface film including one or two layers is formed between the positive electrode and the uppermost P-type layer of the group II-VI semiconductor film, to make the energy band increase in steps from the electrode to the semiconductor film, thereby realizing a structure where the current flows at a low voltage. The II-VI semiconductor film is MBE-grown at a substrate temperature of 350.degree. C. or below. The P-type interface film is formed to have a carrier concentration of 10.sup.19 /cm.sup.3 or above by MBE growth at a substrate temperature lower than or equal to the substrate temperature at which the semiconductor film is formed.

Abstract: A semiconductor light-emitting device employs a quantum well having a fundamental wavelength in the absence of an external electric field; a microcavity with two reflectors, having a resonance wavelength which closely corresponds to the fundamental wavelength of the quantum well; and electrodes for applying an electric field across the microcavity to change the wavelength of the quantum well and thereby control the radiance of the microcavity.

Abstract: A semiconductor light emitting element includes a wide band gap energy II-VI semiconductor layer on a p type III-V semiconductor substrate and a III-V semiconductor buffer layer between the semiconductor substrate and the wide band gap energy II-VI semiconductor layer having a band gap energy intermediate those of the semiconductor substrate and the wide band gap energy II-VI semiconductor layer. Energy spikes in the valence band of the element are reduced and the injection efficiency of holes is increased so that a semiconductor light emitting element having a low operation voltage is produced.

Abstract: A luminous element with a high luminous efficiency comprising means for condensing light towards an exit window of the element. Specifically, the luminous element condenses light generated at the luminous area of the luminous element by an optically reflective surface having oblique concentric surface portions.

Abstract: By i) forming a layered structure of an undoped single crystalline Si layer and single crystalline Si.sub.0.8 Ge.sub.0.2 mixed crystal layer on an n-Si(100) substrate, a second undoped single crystalline Si layer on it, and a p type hydrogenated amorphous Si.sub.1-B C.sub.B layer on it, iii) mounting an n-Si.sub.0.55 Ge.sub.0.40 C.sub.0.05 layer on an n-Si(100) substrate and forming a layered structure of an undoped single crystalline Si.sub.0.55 Ge.sub.0.40 C.sub.0.05 layer and Si.sub.0.8 Ge.sub.0.2 layer, an undoped single crystalline Si.sub.0.55 Ge.sub.0.40 C.sub.0.05 layer, and a p-Si.sub.0.55 Ge.sub.0.40 C.sub.0.05 layer sequentially on it or iv) mounting an n type single crystalline Si layer on an n-Si(100) substrate and forming a layered structure of an undoped single crystalline Si layer and Si.sub.0.8 Ge.sub.0.1 Sn.sub.0.1 layer, an undoped single crystalline Si layer, and a p type single crystalline Si layer sequentially on it, a semiconductor optical device is obtained.

Abstract: A light emitting diode emits in the blue portion of the visible spectrum and is characterized by an extended lifetime. The light emitting diode comprises a conductive silicon carbide substrate; an ohmic contact to the silicon carbide substrate; a conductive buffer layer on the substrate and selected from the group consisting of gallium nitride, aluminum nitride, indium nitride, ternary Group III nitrides having the formula A.sub.x B.sub.1-x N, where A and B are Group III elements and where x is zero, one, or a fraction between zero and one, and alloys of silicon carbide with such ternary Group III nitrides; and a double heterostructure including a p-n junction on the buffer layer in which the active and heterostructure layers are selected from the group consisting of binary Group III nitrides and ternary Group III nitrides.

Abstract: LEDs and other semiconductor devices fabricated with III-V materials and having exposed Al-bearing surfaces passivated with native oxides are disclosed. A known high temperature water vapor oxidation process is used to passivate the exposed layers of Al-bearing III-V semiconductor materials in confined-emission spot LEDs and other light emitting devices. These devices exhibit greatly improved wet, high temperature operating life, with little to no degradation in light output when exposed to such conditions.

Abstract: A semi-conductor light-emitting device has a substrate, an active layer formed on the substrate for emitting light when an electric current is supplied, a current spreading layer formed on the active layer for spreading an electric current, a light-outputting layer formed on the current spreading layer, and electrodes provided on the semiconductor substrate and the light emitting layer for providing electric current to the active layer. In the device, the current spreading layer is formed of zinc telluride (ZnTe).

Abstract: A method of forming a light emitting diode (LED) includes providing a temporary growth substrate that is selected for compatibility with fabricating LED layers having desired mechanical characteristics. For example, lattice matching is an important consideration. LED layers are then grown on the temporary growth substrate. High crystal quality is thereby achieved, whereafter the temporary growth substrate can be removed. A second substrate is bonded to the LED layers utilizing a wafer bonding technique. The second substrate is selected for optical properties, rather than mechanical properties. Preferably, the second substrate is optically transparent and electrically conductive and the wafer bonding technique is carried out to achieve a low resistance interface between the second substrate and the LED layers. Wafer bonding can also be carried out to provide passivation or light-reflection or to define current flow.

Abstract: This invention provides a semiconductor light-emitting device including a semiconductor substrate consisting of a compound semiconductor of elements in the third and fifth groups of the period table, a first compound semiconductor layer formed directly on at least a portion of the semiconductor substrate and consisting of a compound semiconductor containing at least In and P, and a second compound semiconductor formed directly on the first compound semiconductor layer and consisting of a compound semiconductor of elements in the second and sixth groups of the periodic table. With this arrangement, it is possible to sufficiently prevent the occurrence of defects in the interface between the semiconductor substrate and the second compound semiconductor layer consisting of the compound semiconductor of the elements in the second and sixth groups of the periodic table.

Abstract: A Type II heterojunction formed of semiconductor material which normally forms a Type I heterojunction. The Type II heterojunction is created by using a carefully chosen stack of epitaxial semiconductor materials with modifications to the band structure through quantum mechanical confinement effects. This virtual type II heterojunction is incorporated adjacent to the active region in a single-quantum-well, ridge-waveguide laser structure. An anomalous "Negative-T.sub.o " region is observed in which threshold current decreases with increasing temperature. A reduction in the temperature sensitivity of the threshold current of the laser structure results.

Abstract: A surface emitting AlGaInP LED having an ITO layer as a window layer to eliminate the current crowding effect, and an ohmic contact layer between its double hetero-structure of AlGaInP and the ITO layer, so that ITO can be utilized with the double hetero-structure of AlGaInP.

Abstract: In a semiconductor light emitting device of a group II-V semiconductor, a current blocking layer for passing the current only through a central stripe area is formed in one of the two light clad layers sandwiching an active layer, so that the light emission efficiency improves and a light guiding path is provided. In a process for forming each layer on a substrate through epitaxial growth, the central stripe area is formed by etching the current blocking layer.

Abstract: A quantum well structure is provided which is capable of efficiently confining electrons and holes in a quantum well layer. The quantum well structure includes a first cladding layer, a second cladding layer, and a plurality of quantum well layers and one or more barrier layers each disposed between the first cladding layer and the second cladding layer. The quantum well layers and the barrier layers are laminated in an alternating manner. The quantum well layers include at least two selected from the group consisting of a layer having tensile strain, a layer having no strain, and a layer having compressive strain. The thickness of each of the quantum well layers is selected so that the energy difference in each of the quantum well layers between the ground quantum state of an electron at the conduction band and the ground quantum state of a hole at the valence band is substantially the same.

Abstract: An optoelectronic semiconductor device includes a first cladding layer (1) of the first conductivity type provided on a substrate (11), an active layer (2), a second cladding layer (3) of a second conductivity type, an intermediate layer (4), and a third cladding layer (5) also of the second conductivity type, the thickness of the second cladding layer (3) being such that the intermediate layer (4) lies within the optical field profile of the active layer (2), while the intermediate layer (4) includes a semiconductor material with a lower bandgap than the second (3) and third (5) cladding layers. Such devices, often in the form of diode lasers, are used inter alia in optical glass fibre communication and optical disc systems. A disadvantage of such devices is that their starting currents are comparatively high.

Abstract: A semiconductor light emitting device. An emitting region has an active layer which emits short wavelength light and long wavelength light caused by inducing some amount of strain. A first reflective layer reflects the short wavelength light to the emitting region, and a second reflective layer reflects the long wavelength light to the emitting region and transmits the short wavelength light. The emitting region is between the first and the second reflective layers. Thereby the short wavelength light is emitted from the second reflective layer.

Abstract: A light emitting device and a method of fabricating the same in which a first cladding layer is formed on a substrate, then red, green and blue light emitting portions each made of II-VI semiconductor are formed in a horizontal direction with respect to a surface of the substrate on the first cladding layer, then a second cladding layer is formed on the light emitting portions, and the red, green and blue light emitting portions are electrically separated from each other so that three primary color light emitting portions of a self luminous type are formed on the same substrate through single crystal growth process by changing composition of a compound semiconductor layer.

Abstract: A semiconductor light emitting device has an emittive layer formed on a semiconductor substrate, the emittive layer which emits light by being activated with an electric current. Between the substrate and the emittive layer, a reflective layer is formed. In addition, an electrode, which has an aperture for transmitting light emission to the outside of this device, is provided on the emittive layer. In such a structure, at least either one of the reflective layer or the emittive layer is selectively formed right under the aperture formed in the electrode and has the same area as that of the aperture. According to this structure, the emitted light generated laterally from this device is so suppressed that the directivity of light emission is greatly improved in this device.

Abstract: A semiconductor optical guided-wave device which makes quantization and integration possible and which is fine in structure and low in loss is provided, which comprises a semiconductor substrate, at least one ridge type semiconductor optical waveguide formed thereon and at least one pair of electrodes for applying an electric field to the waveguide. The ridge of the optical waveguide is formed by a selective crystal growth process.. The ridge can be realized preferably in such a method that a mask having an opening at a position where a ridge is formed is patterned to a layer on which the ridge is formed, and the crystal growth of a material for forming the ridge is made by a crystal growth technology such as the MOVPE method. The mask to be used for the crystal growth purpose is preferably a thin dielectric film such as, for example, SiO.sub.2 film.

Abstract: An AlGaInP double heterojunction structure or an AlGaInP single heterojunction structure is formed on a first conductivity-type GaAs substrate, and then a layer made of a second conductivity-type Al.sub.w Ga.sub.1-w As.sub.1-v P.sub.v mixed crystal (Al.sub.0.7 Ga.sub.0.3 As.sub.0.97 P.sub.0.03, for example) which has the bandgap energy larger than the energy of photon emitted from the active layer of said light emitting layer portion, and has good lattice-matching with (Al.sub.B Ga.sub.1-B).sub.0.51 In.sub.0.49 P mixed crystal (layer) constituting said light emitting layer portion, is formed as a current spreading layer on top of said light emitting layer portion. Here, w and v are in the range of 0.45.ltoreq.w<1 and 0<v.ltoreq.0.08, respectively.

Abstract: A semiconductor light emitting device has a light emitting layer portion comprising AlGaInP layers formed on a GaAs substrate. A light reflecting layer portion comprising alternately laminated layers with different refractive indices is provided between the GaAs substrate and the light emitting layer portion. The light reflecting layer portion comprises Al.sub.w Ga.sub.1-w As.sub.1-v P.sub.v layers (where: 0.ltoreq.w.ltoreq.1, 0<v.ltoreq.0.05 w). An active layer which constitutes the light emitting layer portion comprises an (Al.sub.y Ga.sub.1-y).sub.0.51 In.sub.0.49 P layer (where: 0.ltoreq.y.ltoreq.0.7).

Abstract: A semiconductor structure useful in blue light emitting diodes and diode lasers is disclosed. The structure is formed of a substrate of p- type GaAs, a layer of a p- type II-VI compound of the formula Zn.sub.x Q.sub.1-x S.sub.y Se.sub.1-x where Q=Mg, Cd or Mn, 0.5.ltoreq.x.ltoreq.1 and 0.ltoreq.y.ltoreq.1, separated from the substrate by a series of thin epitaxial undoped or p-doped layers including a layer of In.sub.0.5 Al.sub.0.5 P in contact with the layer of the II-VI compound, a layer of In.sub.0.5 Ga.sub.0.5 P or of Al.sub.x Ga.sub.1-x As where x=0.1-0.3 contacting the substrate, a layer of In.sub.0.5 Ga.sub.0.5 P contacting the layer of Al.sub.x Ga.sub.1-x P and at least one layer of In.sub.0.5 Al.sub.2 Ga.sub.0.5-z P where 0<z<0.5 and the value of z decreases in the direction of the layer of In.sub.0.5 Ga.sub.0.5 P provided between and contacting the layer of In.sub.0.5 Al.sub.0.5 P and the layer of In.sub.0.5 Ga.sub.0.5 P.

Abstract: A semiconductor light emitting element comprising plural semiconductor layers inclusive of a light emitting part having a pn junction, which are laminated on a crystal substrate, wherein a first semiconductor layer, having a carrier concentration of not more than 5.times.10.sup.17 cm.sup.-3 and a band gap of not less than the energy of the light emitted from the light emitting part, is formed in the passage of the light emitted from the light emitting part toward the substrate side, and a second semiconductor layer, having a carrier concentration of not more than 5.times.10.sup.17 cm.sup.-3 and a band gap of not greater than the energy of the light emitted from the light emitting part, is formed behind (when seen from the passage of the light) the first layer. According to the present invention, sub-peak wavelength light emission can be suppressed to a satisfactory degree.

Abstract: An optoelectronic device having a very low stray capacitance and its production process.

Abstract: A semiconductor laser diode of a double hetero structure including a semiconductor substrate, a buffer layer, a clad layer of a first conductivity type, an active layer and a clad layer of a second conductivity type, all layers being sequentially formed over the substrate, characterized by an intermediate layer interposed at at least one of a region between the substrate and the first clad layer and a region between the second clad layer and the cap layer, the intermediate layer being adapted to reduce a series resistance component and thus make a flow of current smooth.

Abstract: A semiconductor light-emitting device and a manufacturing method therefor by which deterioration of external output is sufficiently suppressed under the high temperature and moisture so as to significantly improve pellet yield. A light emitting device of a double hetero structure, includes: a first GaAlAs clad layer of a first conductivity type; an active layer formed on the first clad layer, the active layer having an appropriate AlAs mixed crystal ratio relative to a GaAs crystal so that an emitted light wavelength from the device is substantially between 620 and 940 nm; and a second GaAlAs clad layer of a second conductivity type formed on the active layer, wherein the AlAs mixed crystal ratio on the surface thereof in the second clad layer is equal to or less than 0.67, and a difference of the AlAs mixed crystal ratio between the bottom layer of the first clad layer and the top layer of the second clad layer is equal to or less than 0.3.

Abstract: An object of the invention to vary a light absorption coefficient within wider limits in a light absorption control semiconductor device. The device includes at least three quantum wells Q1, Q2, Q3. The width of the respective quantum wells and barriers is set such that wave functions of electrons in the respective quantum wells interact in a resonance state where the quantized energy levels in either one of conduction and valence bands are matched. In addition, the width and material of the respective quantum wells are set so that one of the bands is brought into the resonance state where the quantized energy levels at the respective quantum wells are matched in a state where no electric field is applied or a state where a suitable electric field is applied in a direction perpendicular to the junctions. The light absorption is changed by controlling components of the electric field perpendicular to the junctions.

Abstract: A semiconductor light emitting element comprising a semiconductor substrate having a lower electrode on its back, a pn junction, a first light reflecting layer disposed between the substrate and the pn junction, an upper electrode, and a second light reflecting layer disposed between the pn junction and the upper electrode, the second light reflecting layer being capable of substantially reflecting the light heading toward the upper electrode, which preferably has, between the pn junction and the second light reflecting layer, a semiconductor layer having a wider bandgap than that of a light emitting layer formed by said pn junction. The semiconductor light emitting element of the invention is advantageous in that the light absorption in the upper electrode can be inhibited to permit efficient output of the light heading toward the upper electrode from the element, and luminance can be greatly increased by the effective output of the light from the element.

Abstract: A light-emitting diode, in which light is emitted from a side opposite to a substrate, includes a compound semiconductor substrate of a first conductivity type, a lower cladding layer formed on the substrate end consisting of InGaAlP of the first conductivity type, a light-emitting layer formed on the lower cladding layer and having a quantum well structure constituted by alternately stacking barrier layers and eight or more quantum well layers, and an upper cladding layer formed on the light-emitting layer and consisting of InGaAlP of a second conductivity type.

Abstract: There are disclosed a low driving voltage surface emitting semiconductor laser and an optoelectronic integrated which comprises a two-dimensional array of such surface emitting semiconductor lasers which are modulatable with input signals of small voltage amplitudes. In an embodiment of the present invention, an optical semiconductor device includes a GaAs substrate 105, and an epitaxial growth layer structure on the GaAs substrate, the epitaxial growth layer structure including in the named order a p type GaAs/AlAs multilayer semiconductor mirror layer 104, an active layer 103 and an n type GaAs/AlAs multilayer semiconductor mirror layer 102. The epitaxial growth layer structure is etched to the depth of the active layer in forming a mesa, while the p type mirror layer remains unetched throughout a top surface of the semiconductor substrate.

Abstract: Quasi-phase matched (QPM) second-harmonic (SH) generation in the reflection geometry is described. The SH intensity can be strongly enhanced by spatially modulating the optical properties of the nonlinear medium. This type of quasi-phase matching is demonstrated using an Al.sub.0.8 Ga.sub.0.2 As/GaAs heterostructure designed for .lambda.=1.06 .mu.m incident light. The SH light intensity generated in reflection from the heterostructure is enhanced 70 times relative to the SH response of a homogeneous GaAs wafer. A Fabry-Perot resonant cavity design employs this structure to make thin films with extremely high SH generation efficiencies. This is of particular interest used in vertical cavity surface emitting lasers (VCSELs).

Abstract: A semiconductor light emitting device which allows part of an active layer to generate light by supplying current to the part of the active layer is disclosed. The semiconductor light emitting device includes: a semiconductor substrate having upper and lower surfaces, the upper surface having a stepped portion, the stepped portion dividing the upper surface into at least a first area and a second area; a current confining layer, formed on the upper surface of the substrate, the current confining layer being discontinuous at the stepped portion, the current flowing through an area between the first area and the second area of the substrate; a multilayer structure formed on the current confining layer, the multilayer structure including the active layer; a first electrode which covers only part of an upper surface of the multilayer structure; and a second electrode formed over the lower surface of the substrate.

Abstract: Radiation-emitting semiconductor diodes in the form of a laser diode or in the form of an LED form important components in data-processing systems. There is a particular need for diodes which emit in the visible part of the spectrum, which have a low starting current and which can be manufactured at low cost. A radiation-emitting semiconductor diode comprising above the active layer a cladding layer and a GaAs contact layer, into which a mesa-shaped strip is etched, and provided on the upper and the lower side with a conductive layer, which forms outside the mesa-shaped strip a junction forming a barrier with a subjacent semiconductor layer, partly satisfies the aforementioned requirements.

Abstract: The invention provides a semiconductor optical surface transmission device comprising a laser element and a photo-transistor element formed on a semiconductor substrate through which light transmissions are made. Each of the laser element and the photo-transistor element has top and bottom reflective mirrors, but the bottom reflective mirror of the photo-transistor element includes a phase inversion layer to form a double resonator for detecting injection lights in a wide range of those wavelength at a high efficiency of absorption of the injection lights.

Abstract: A superluminescent diode (SLD) includes a substrate, a double heterojunction structure including a first conductivity type first cladding layer, an undoped active layer, and a second conductivity type second cladding layer. A second conductivity type first diffused region having a stripe shape and a length extends from a front facet halfway to the rear facet through which current is injected into the active layer and a second conductivity type second diffused region spaced from the first diffused region extends through the second cladding layer and the active layer and into the first cladding layer between the first diffused region and the rear facet of the device. Even when operating at high light output power, light reflections are reduced so that the SLD operates with hardly any laser oscillation.

Abstract: An optical modulating element has a core layer and first and second cladding layers sandwiching the core layer. The core layer is made of one or semiconductors belonging to a point group 43m or 42m, and has TM.sub.00 and TE.sub.00 propagation modes. The direction of light of said TM.sub.00 and TE.sub.00 propagation modes is parallel to the [110] or [-110] direction of crystal orientation. The change amount of an index of refraction of the core layer caused by the application of an electric field to the core layer in the direction parallel to the [001] direction is different for the two propagation modes.

Abstract: A semiconductor infrared emitting device is fabricated from an n-type gallium arsenide substrate, an n-type gallium arsenide layer on the top surface of the substrate, a p-type gallium arsenide layer formed on the n-type gallium arsenide layer for forming a p-n junction therebetween, and electrodes provided on the p-type gallium arsenide layer and the reverse surface of the substrate for applying a bias voltage to the p-n junction, and the side surface of the substrate declines from the cleavage surface of the gallium arsenide substrate so that the incident angle of infrared varies at the crystal surfaces, thereby allowing the infrared to be radiated from the semiconductor infrared emitting device.