Abstract: The present invention is related to a supporting substrate for manufacturing vertically-structured semiconductor light emitting device and a vertically-structured semiconductor light emitting device using the same, which minimize damage and breaking of a multi-layered light-emitting structure thin film separated from a sapphire substrate during the manufacturing process, thereby improving the whole performance of the semiconductor light emitting device.

Abstract: A light-emitting device includes a substrate, a first doped semiconductor layer situated above the substrate, a second doped semiconductor layer situated above the first doped layer, and a multi-quantum-well (MQW) active layer situated between the first and the second doped layers. The device also includes a first electrode coupled to the first doped layer and a first passivation layer situated between the first electrode and the first doped layer in areas other than an ohmic-contact area. The first passivation layer substantially insulates the first electrode from edges of the first doped layer, thereby reducing surface recombination. The device further includes a second electrode coupled to the second doped layer and a second passivation layer which substantially covers the sidewalls of the first and second doped layers, the MQW active layer, and the horizontal surface of the second doped layer.

Abstract: A light-emitting body of rapid speed of response and high light emission intensity, and an electron beam detector, scanning electron microscope and mass spectroscope using this are provided. In the light-emitting body 10 according to the present invention, when fluorescence is emitted by a nitride semiconductor layer 14 formed on one face 12a of a substrate 12 in response to incidence of electrons, at least some of this fluorescence is transmitted through this substrate 12, whereby that fluorescence is emitted from the other face 12b of the substrate. The response speed of this fluorescence is not more than ?sec order. Also, the intensity of emission of this fluorescence is almost identical to that of a conventional P47 phosphor. Specifically, with this light-emitting body 10, a response speed and light emission intensity are obtained that are fully satisfactory for application to a scanning electron microscope or mass spectroscope.

Abstract: An optoelectronic semiconductor body comprises a semiconductor layer sequence which is subdivided into at least two electrically isolated subsegments. The semiconductor layer sequence has an active layer in each subarea. Furthermore, at least three electrical contact pads are provided. A first line level makes contact with a first of the at least two subsegments and with the first contact pad. A second line level makes contact with the second of the at least two subsegments and with a second contact pad. A third line level connects the two subsegments to one another and makes contact with the third contact pad. Furthermore, the line levels are each arranged opposite a first main face, wherein the first main face is intended to emit electromagnetic radiation that is produced.

Abstract: A light emitting device may include a semiconductor light emitting diode which may include a first nitride semiconductor layer doped as an n-type, a second nitride semiconductor layer doped as a p-type, and a first active layer provided between the first and second nitride semiconductor layers, and a nano light emitting diode array in which a plurality of nano light emitting diodes may be arranged on the semiconductor light emitting diode so as to be separated from each other.

Abstract: A method for improving internal quantum efficiency of a group-III nitride-based light emitting device is disclosed. The method includes the steps of: providing a group-III nitride-based substrate having a single crystalline structure; forming on the group-III nitride-based substrate an oxide layer, having a plurality of particles, without absorption of visible light, size, shape, and density of the particles are controlled by reaction concentration ratio of nitrogen/hydrogen, reaction time and reaction temperature; and growing a group-III nitride-based layer over the oxide layer; wherein the oxide layer prevents threading dislocation of the group-III nitride-based substrate from propagating into the group-III nitride-based layer, thereby improving internal quantum efficiency of the group-III nitride-based light emitting device.

Abstract: Arrays of light-emitting devices, and related components, processes, systems and methods are disclosed.

Abstract: A light-emitting diode and a method for manufacturing the same are described. The light-emitting diode includes a bonding substrate, a first conductivity type electrode, a bonding layer, an epitaxial structure, a second conductivity type electrode, a growth substrate and an encapsulant layer. The first conductivity type electrode and the bonding layer are respectively disposed on two surfaces of the bonding substrate. The epitaxial structure includes a first conductivity type semiconductor layer, an active layer and a second conductivity type semiconductor layer. A trench is set around the epitaxial structure and extends from the second conductivity type semiconductor layer to the first conductivity type semiconductor layer. The second conductivity type electrode is electrically connected to the second conductivity type semiconductor layer. The growth substrate is disposed on the epitaxial structure and includes a cavity exposing the epitaxial structure and the trench.

Abstract: An embodiment relates to a nanowire-containing LED device with optical feedback comprising a substrate, a nanowire protruding from a first side the substrate, an active region to produce light, a optical sensor and a electronic circuit, wherein the optical sensor is configured to detect at least a first portion of the light produced in the active region, and the electronic circuit is configured to control an electrical parameter that controls a light output of the active region. Yet, another embodiment relates to an image display having the nanowire-containing LED device with optical feedback.

Abstract: A nanopyramid LED and method for forming. The nanopyramid LED includes a silicon substrate, a III-nitride layer deposited thereon, a metal layer deposited thereon; and a nanopyramid LED grown in ohmic contact with the metal layer. The nanopyramid LED can be seeded on the III-nitride layer or metal layer. The metal layer can be a reflecting surface for the nanopyramid LED. The method for forming nanopyramid LEDs includes obtaining a silicon substrate, depositing a III-nitride layer thereon, depositing a metal layer thereon, depositing a dielectric growth layer thereon, etching a dielectric growth template in the growth layer, and growing III-nitride nanopyramid LEDs through the dielectric growth template in ohmic contact with the metal layer. The etching can be performed by focused ion beam etching. The etching can stop in the metal layer or III-nitride layer, so that the nanopyramid LEDs can seed off the metal layer or III-nitride layer, respectively.

Abstract: Optoelectronic devices, junctions and methods of fabricating a device or junction where the emitter layer is of an indirect-band-gap material and the base layer is of a direct-band-gap material. The device or junction may have, among other structures and layers, a base layer of a first semiconductor material having a first conductivity type and further having a direct band gap and an emitter layer forming a junction with the base layer. In this embodiment, the emitter layer may be of a second semiconductor material having a second conductivity type and further having an indirect band gap. The optoelectronic device may have the semiconductor material of the emitter layer substantially lattice mismatched with the semiconductor material of the base layer in bulk form. Alternatively, the emitter layer may be substantially lattice matched with the base layer.

Abstract: A semiconductor body includes an n-conductive semiconductor layer and a p-conductive semiconductor layer. The p-conductive semiconductor layer contains a p-dopant and the n-conductive semiconductor layer an n-dopant and a further dopant.

Abstract: A light-emitting device allowed to obtain polarized light without increasing the number of components or the thickness thereof, and a display including the light-emitting device are provided. The light-emitting device includes: a light-emitting element including, on a substrate, a first electrode, a light-emitting layer and a second electrode in order from the substrate. The substrate has, on a surface facing the first electrode, a first concavo-convex structure including a plurality of strip-shaped protrusion sections with a width equal to or smaller than an upper wavelength limit of visible light, and the first electrode, the light-emitting layer and the second electrode each have, on a surface opposite to a surface facing the substrate, a second concavo-convex structure imitating the protrusion sections of the first concavo-convex structure.

Abstract: A high brightness light emitting diode includes a carrier substrate and an epitaxial multi-layer formed thereon. The carrier substrate includes a metal material and a medium, and a coefficient of thermal expansion (CTE) of the medium is less than a CTE of the metal material.

Abstract: A light emitting diode array in which, when viewed from the above, the shape of an almost square light emitting diode is square-chamfered or round-chamfered at the corners thereof in order to minimize light leakage at a reverse mesa surface to allow an electrode layer to surround the three directions of a light emitting unit, and part in the vicinity of the corner of the reverse mesa surface is extended up to a substrate unit to cover it. Accordingly, the light emitting diode array minimized in light leakage at the reverse mesa surface can be provided.

Abstract: A transparent-substrate light-emitting diode (10) has a light-emitting layer (133) made of a compound semiconductor, wherein the area (A) of a light-extracting surface having formed thereon a first electrode (15) and a second electrode (16) differing in polarity from the first electrode (15), the area (B) of a light-emitting layer (133) formed as approximating to the light-extracting surface and the area (C) of the back surface of a light-emitting diode falling on the side opposite the side for forming the first electrode (15) and the second electrode (16) are so related as to satisfy the relation of A>C>B. The light-emitting diode (10) of this invention, owing to the relation of the area of the light-emitting layer (133) and the area of the back surface (23) of the transparent substrate and the optimization of the shape of a side face of the transparent substrate (14), exhibits high brightness and high exoergic property never attained heretofore and fits use with an electric current of high degree.

Abstract: A light emitting device and a light emitting device package including the same are provided. The light emitting device may include a light emitting structure including a first conductive type semiconductor layer, an active layer, and a second conductive type semiconductor layer, a first electrode on the light emitting structure, the first electrode including a pattern, and a pad electrode on the first electrode.

Abstract: Disclosed are a semiconductor light emitting device and a method for manufacturing the same. The semiconductor light emitting device comprises a substrate, in which concave-convex patterns are in at least a portion of a backside of the substrate, and a light emitting structure on the substrate and comprising a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer.

Abstract: An LED arrangement (light emitting diode) has a plurality of adjacent radiating LEDs that are nearly identically aligned for forming an extended area light source. The LEDs are attached to a metallic multi-film support having sandwich-like insulating intermediate layers and having at least a step-like structure with at least one step. At least one LED chip is placed on each step on a metal film and the metal layer directly above is formed of a corresponding shortening or recess for mounting an LED.

Abstract: According to an aspect of the invention, an optical functional element includes a substrate, a semiconductor element portion, and a light emitting element portion. The semiconductor element portion includes a first part of a semiconductor multi layer structure formed on the substrate. The light emitting element portion includes a second part of the semiconductor multi layer structure and light emitting element structure formed on the second part of the semiconductor multi layer structure.

Abstract: An epitaxial wafer, a light-emitting element, a method of fabricating the epitaxial wafer and a method of fabricating the light-emitting element, which have a high output and a low forward voltage, and can be fabricated without increasing fabricating cost, are provided.

Abstract: In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle ? from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle ? is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP? with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP? and the gallium nitride based semiconductor layer P.

Abstract: A nitride semiconductor light-emitting device wherein a substrate or nitride semiconductor layer has a defect concentration region and a low defect density region other than the defect concentration region. A portion including the defect concentration region of the nitride semiconductor layer or substrate has a trench region deeper than the low defect density region. Thus by digging the trench in the defect concentration region, the growth detection is uniformized, and the surface planarity is improved. The uniformity of the characteristic in the wafer surface leads to improvement of the yield.

Abstract: A nitride semiconductor laser device uses a substrate with low defect density, contains reduced strains inside a nitride semiconductor film, and thus offers a satisfactorily long useful life. On a GaN substrate (10) with a defect density as low as 106 cm?2 or less, a stripe-shaped depressed portion (16) is formed by etching. On this substrate (10), a nitride semiconductor film (11) is grown, and a laser stripe (12) is formed off the area right above the depressed portion (16). With this structure, the laser stripe (12) is free from strains, and the semiconductor laser device offers a long useful life. Moreover, the nitride semiconductor film (11) develops reduced cracks, resulting in a greatly increased yield rate.

Abstract: A semiconductor light emitting device, includes: a stacked structural unit including a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting layer provided therebetween; and an electrode including a first and second metal layers, the first metal layer including silver or silver alloy and being provided on a side of the second semiconductor layer opposite to the light emitting layer, the second metal layer including at least one element selected from gold, platinum, palladium, rhodium, iridium, ruthenium, and osmium and being provided on a side of the first metal layer opposite to the second semiconductor layer. A concentration of the element in a region including an interface between the first and second semiconductor layers is higher than that of the element in a region of the first metal layer distal to the interface.

Abstract: Described herein is a method for manufacturing a nitride semiconductor layer by stacking, on a silicon nitride layer, the first nitride semiconductor layer having a surface inclined with respect to the surface of the silicon nitride layer and then stacking the second nitride semiconductor layer on the first nitride semiconductor layer, a nitride semiconductor element and a nitride semiconductor light-emitting element each including the nitride semiconductor layer; and a method for manufacturing the nitride semiconductor element.

Abstract: Disclosed is a method of fabricating a light emitting diode using a laser lift-off apparatus. The method includes growing an epitaxial layer including a first conductive-type compound semiconductor layer, an active layer and a second conductive-type compound semiconductor layer on a first substrate, bonding a second substrate, having a different thermal expansion coefficient from that of the first substrate, to the epitaxial layers at a first temperature of the first substrate higher than a room temperature, and separating the first substrate from the epitaxial layer by irradiating a laser beam through the first substrate at a second temperature of the first substrate higher than the room temperature but not more than the first temperature. Thus, during a laser lift-off process, focusing of the laser beam can be easily achieved and the epitaxial layers are prevented from cracking or fracture. The laser lift-off process is performed by a laser lift-off apparatus including a heater.

Abstract: The AlGaN upper cladding layer of a nitride laser diode is replaced by a non-epitaxial layer, such as metallic silver. If chosen to have a relatively low refractive index value, the mode loss from absorption in the non-epitaxial cladding layer is acceptably small. If also chosen to have a relatively high work-function, the non-epitaxial layer forms an electrical contact to the nitride semiconductors. An indium-tin-oxide layer may also be employed with the non-epitaxial cladding layer.

Abstract: Light emitting chips, light emitting unit cells and methods of forming light emitting chips are provided. A light emitting chip includes a light emission structure having a p-type semiconductor layer, an n-type semiconductor layer, and an active layer therebetween. At least one light emitting unit is formed from the light emission structure including a light emitting diode (LED) and a plurality of light receiving diode (LRD) portions. The LRD portions are serially connected and configured to surround the LED portion. The LRD portions are optically coupled to the LED portion to receive total internal reflection (TIR) light from the LED portion and convert the TIR light to a photocurrent.

Abstract: An electrode structure is disclosed for enhancing the brightness and/or efficiency of an LED. The electrode structure can have a metal electrode and an optically transmissive thick dielectric material formed intermediate the electrode and a light emitting semiconductor material. The electrode and the thick dielectric cooperate to reflect light from the semiconductor material back into the semiconductor so as to enhance the likelihood of the light ultimately being transmitted from the semiconductor material. Such LED can have enhanced utility and can be suitable for uses such as general illumination.

Abstract: The present invention is directed to LED packages and LED displays utilizing the LED packages, wherein the LED chips within the packages are arranged in unique orientations to provide the desired package or display FFP. One LED package according to the present invention comprises a reflective cup and an LED chip mounted in the reflective cup. The reflective cup has a first axis and a second axis orthogonal to the first axis, wherein the LED chip is rotated within the reflective cup so that the LED chip is out of alignment with said first axis. Some of the LED packages can comprise a rectangular LED chip having a chip longitudinal axis and an oval shaped reflective cup having a cup longitudinal axis. The LED chip is mounted within the reflective cup with the chip longitudinal axis angled from the cup longitudinal axis.

Abstract: In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle ? from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle ? is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP? with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP? and the gallium nitride based semiconductor layer P.

Abstract: A semiconductor light-emitting element array device includes a substrate; a plurality of removable layers being disposed on the substrate; and a thin-film semiconductor light-emitting device being disposed on each of the plurality of removable layers, being made of a different material from a surface material of the substrate, and having a semiconductor light-emitting element; wherein the plurality of removable layers are made of a material which is capable of being etched by a selective chemical etching process. An image exposing device includes an image exposing unit including the semiconductor light-emitting element array device. An image exposing device includes an image exposing unit including the semiconductor light-emitting element array device. An image display apparatus includes an image display unit including the semiconductor light-emitting element array device.

Abstract: A nitride semiconductor light-emitting device comprises a substrate, and a first n-type nitride semiconductor layer, an emission layer, a p-type nitride semiconductor layer, a metal layer and a second n-type nitride semiconductor layer stacked on the substrate successively from the side closer to the substrate, with an electrode provided on the surface of the second n-type nitride semiconductor layer or above the surface of the second n-type nitride semiconductor layer. The metal layer is preferably made of a hydrogen-storage alloy.

Abstract: A method of device growth and p-contact processing that produces improved performance for non-polar III-nitride light emitting diodes and laser diodes. Key components using a low defect density substrate or template, thick quantum wells, a low temperature p-type III-nitride growth technique, and a transparent conducting oxide for the electrodes.

Abstract: The present invention relates to a high quantum efficiency lighting device comprising a solid state light source (54) and at least one light influencing element (10), being adapted to influence light emitted from solid state light source. The light influencing element (10) comprises a first electrode layer (11), and a second electrode layer (13), wherein the second electrode layer (13) is biased to remain in a rolled-up state, and adapted to be unrolled into an unrolled state in response to an electric potential applied between the first and second electrode layers, said second electrode layer in its unrolled state, extending across said optical light path, and being adapted to influence light emitted from the solid state light source (54).

Abstract: Provided is a method of manufacturing a vertical light emitting device.

Abstract: A light emitting device according to the embodiment includes a first conductive semiconductor layer; an active layer under the first conductive semiconductor layer; a second conductive semiconductor layer under the active layer; a current blocking region under the second conductive semiconductor layer; a second electrode layer under the second conductive semiconductor layer and the current blocking region; and a first electrode layer including a protrusion protruding toward the first conductive semiconductor layer arranged, on the first conductive semiconductor layer.

Abstract: A light emitting device has a light emitting layer having a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, and an active layer sandwiched between the first semiconductor layer and the second semiconductor layer, a reflecting layer provided on a side of one surface of the light emitting layer, which reflects a light emitted from the active layer, a supporting substrate provided on an opposite side of the reflecting layer with respect to the light emitting layer, which supports the light emitting layer via an adhesion layer, an ohmic contact portion provided on a part of the reflecting layer, which electrically connects between the reflecting layer and the light emitting layer, and convexo-concave portions formed on other surface of the light emitting layer and side surfaces of the light emitting layer, respectively, and an insulating film configured to cover the convexo-concave portions.

Abstract: A surface emitting laser includes a lower multilayer mirror and an upper multilayer mirror which are provided on a substrate. A first oxidizable layer is partially oxidized to form a first current confinement layer including a first conductive region and a first insulating region. A second oxidizable layer is partially oxidized to form a second current confinement layer including a second conductive region and a second insulating region, a boundary between the first conductive region and the first insulating region being disposed inside the second current confinement layer in an in-plane direction of the substrate. The first oxidizable layer and the second oxidizable layer or layers adjacent to the respective oxidizable layers are adjusted so that when both layers are oxidized under the same oxidizing conditions, the oxidation rate of the first oxidizable layer is lower than that of the second oxidizable layer.

Abstract: Surface modification of individual nitride semiconductor layers occurs between growth stages to enhance the performance of the resulting multiple layer semiconductor structure device formed from multiple growth stages. Surface modifications may include, but are not limited, to laser patterning, lithographic patterning (with the scale ranging from 10 microns to a few angstroms), actinic radiation modifications, implantation, diffusional doping and combinations of these methods. The semiconductor structure device has enhanced crystal quality, reduced phonon reflections, improved light extraction, and an increased emission area. The ability to create these modifications is enabled by the thickness of the HVPE growth of the GaN semiconductor layer.

Abstract: A surface emitting laser includes a lower multilayer mirror, an active layer, and an upper multilayer mirror stacked onto a substrate. A first current confinement layer having a first electrically conductive region and a first insulating region is formed above or below the active layer using a first trench structure. A second current confinement layer having a second electrically conductive region and a second insulating region is formed above or below the first current confinement layer using a second trench structure. The first and second trench structures extend from a top surface of the upper multilayer mirror towards the substrate such that the second trench structure surrounds the first trench structure. When the surface emitting laser is viewed in an in-plane direction of the substrate, a boundary between the first electrically conductive region and the first insulating region is disposed inside the second electrically conductive region.

Abstract: A semiconductor light emitting device including a semiconductor substrate and an active layer which is formed on the substrate and has a cascade structure formed by multistage-laminating unit laminate structures 16 each including an emission layer 17 and an injection layer 18 is configured. The unit laminate structure 16 has a first upper level L3, a second upper level L4, and a lower level L2 in the emission layer 17, and an injection level L1 in the injection layer 18, an energy interval between the levels L3 and L4 is set to be smaller than the energy of an LO phonon, the layer thickness of the exit barrier layer is set in a range not less than 70% and not more than 150% of the layer thickness of the injection barrier layer, light is generated by emission transition in the emission layer 17, and electrons after the emission transition are injected from the level L2 into the level L4 of the emission layer of a subsequent stage via the level L1.

Abstract: In a lighting package, a printed circuit board supports at least one light emitting die. A light transmissive cover is disposed over the at least one light emitting die. A phosphor is disposed on or inside of the light transmissive dome-shaped cover. The phosphor outputs converted light responsive to irradiation by the at least one light emitting die. An encapsulant substantially tills an interior volume defined by the light-transmissive cover and the printed circuit board.

Abstract: A semiconductor light emitting device and a method of manufacturing the same are provided. The semiconductor light emitting device comprises a first semiconductor layer emitting electrons, a second semiconductor layer emitting holes, and an active layer emitting light by combination of the electrons and holes. At least one of the layers comprises an photo enhanced minority carriers.

Abstract: The inventive method for manufacturing a semiconductor device is a method for manufacturing a semiconductor device using irradiation with laser light to partition a substrate having semiconductor layers formed thereon, with gallium contained in at least one of the substrate and the semiconductor layers, wherein the method comprises: forming grooves to be used as boundaries between individual substrates by irradiating the substrate along partitioning locations with laser light, immersing the substrate into an acid solution, and partitioning the substrate into individual substrates along the boundaries where grooves are formed. In this manner, it provides a method for manufacturing a semiconductor device in which, during the partitioning of a gallium-containing semiconductor device substrate, deposits of gallium compounds adhered during laser irradiation are removed, partitioning surfaces are formed flat and uniform, and the incidence of electrode continuity failures and resin peeling is low.

Abstract: A semiconductor nanocrystal and a preparation method thereof, where the semiconductor nanocrystal include a bare semiconductor nanocrystal and a water molecule directly bound to the bare semiconductor nanocrystal.

Abstract: A structure for improving the mirror facet cleaving yield of (Ga,Al,In,B)N laser diodes grown on nonpolar or semipolar (Ga,Al,In,B)N substrates. The structure comprises a nonpolar or semipolar (Ga,Al,In,B)N laser diode including a waveguide core that provides sufficient optical confinement for the device's operation in the absence of p-type doped aluminum-containing waveguide cladding layers, and one of more n-type doped aluminum-containing layers that can be used to assist with facet cleaving along a particular crystallographic plane.

Abstract: A semiconductor light emitting device includes a silicon substrate, a p-type semiconductor layer provided on the silicon substrate, a n-type semiconductor layer provided on the silicon substrate, the n-type semiconductor layer adjoining the p-type semiconductor layer, and a light emitting section formed at a p-n homojunction between the p-type semiconductor layer and the n-type semiconductor layer. The p-n homojunction is substantially perpendicular to a major surface of the silicon substrate. The p-n homojunction is corrugated with a period matched with an integer multiple of an emission wavelength at the light emitting section.

Abstract: Semiconductor emitting devices that offset stresses applied to a quantum well region and reduce internal fields due to spontaneous and piezoelectric polarizations are disclosed. In one embodiment, a semiconductor emitting device includes a quantum well region comprising an active layer that emits light and at least one barrier layer disposed adjacent the active layer, a means for impressing an electric field across the quantum well region to inject carriers into the quantum well region, and a means for impressing an offset electric field across the quantum well region to offset the polarization field formed in the quantum well region.