Abstract: A laser diode, grown on a miscut nonpolar or semipolar substrate, with lower threshold current density and longer stimulated emission wavelength, compared to conventional laser diode structures, wherein the laser diode's (1) n-type layers are grown in a nitrogen carrier gas, (2) quantum well layers and barrier layers are grown at a slower growth rate as compared to other device layers (enabling growth of the p-type layers at higher temperature), (3) high Al content electron blocking layer enables growth of layers above the active region at a higher temperature, and (4) asymmetric AlGaN SPSLS allowed growth of high Al containing p-AlGaN layers. Various other techniques were used to improve the conductivity of the p-type layers and minimize the contact resistance of the contact layer.

Abstract: A quantum cascade laser structure in accordance with the invention comprises a number of cascades (100), each of which comprises a number of alternately arranged quantum wells (110a to 110j) and barrier layers (105 to 105j). The material of at least one quantum well (110a to 110j) as well as the material of at least one barrier layer (105 to 105j) is under mechanical strain, with the respective strain being either a tensile strain or a compression strain. The quantum wells (110a to 110j) and barrier layers (105 to 105j) are engineered in the quantum cascade laser structure in accordance with the invention so that existing strains are largely compensated within a cascade (100). In the quantum cascade laser structure in accordance with the invention, each material of the quantum wells (110a to 110j) has only one constituent material and the material of at least one barrier layer (105d, 105e, 105f) has at least two constituent materials (111a, 111b, 112a, 112b, 113a, 113b).

Abstract: The CMOS field effect transistors, used in microprocessors and other digital VLSI circuits, face major challenges such as thin gate dielectrics leakage and scaling limits, severe short channel effects, limited performance improvement with scaling, complicated fabrication process with added special techniques, and surface mobility degradation. This disclosure proposes a new CMOS-compatible optoelectronic transistor. The current is much higher than the MOS transistors, due to the high carrier mobility with bulk transportation. The optoelectronic transistors are scalable to the sub-nanometer ranges without short channel effects. It is also suitable for low power applications and ULSI circuits. The new transistor consists of a laser or LED diode as drain or source, and a photo sensor diode (avalanche photo diode) as source or drain.

Abstract: Semiconductor devices such as VCSELs, SELs, LEDs, and HBTs are manufactured to have a wide bandgap material near a narrow bandgap material. Electron injection is improved by an intermediate structure positioned between the wide bandgap material and the narrow bandgap material. The intermediate structure is an inflection, such as a plateau, in the ramping of the composition between the wide bandgap material and the narrow bandgap material. The intermediate structure is highly doped and has a composition with a desired low electron affinity. The injection structure can be used on the p-side of a device with a p-doped intermediate structure at high hole affinity.

Abstract: The semiconductor laser has a resonator end face (15) and a semiconductor superlattice (16) which is applied to the resonator end face (15). The semiconductor superlattice (16) acts as a passivation layer for the resonator end face (15) and has a number of layers (16.1, 16.2, 16.3, 16.3), the material compositions of which are selected in such a manner that essentially no light is absorbed at the emission wavelength of the semiconductor laser (13), the layer assembly suppresses charge carrier transport from the active layer to the surface of the outermost layer (16.4) and good lattice adaption of the semiconductor superlattice (16) to the semiconductor laser is made possible at the same time.

Abstract: A method of component assembly on a substrate, and an assembly of a bound component on a substrate. The method comprises the steps of forming a free-standing component having an optical characteristic; providing a pattern of a first binding species on the substrate or the free standing component; and forming a bound component on the substrate through a binding interaction via the first binding species; wherein the bound component exhibits substantially the same optical characteristic compared to the free-standing component.

Abstract: A III-V Group GaN-based compound semiconductor device with an improved structure having low current comsumption, high optical output, and a long lifetime is provided. The III-V Group GaN-based compound semiconductor device includes an active layer and a first clad layer and a second clad layer, wherein at least one of the first clad layer and the second clad layer has a superlattice structure formed of a plurality of alternating AlxGa(1-x)N layers (0<x<1) and GaN layers, and the composition ratio of aluminum of the AlxGa(1-x)N layers decreases at a predetermined rate away from the active layer.

Abstract: The semiconductor layer structure comprises a superlattice (9) composed of alternately stacked layers (9a, 9b) of III-V semiconductor compounds of a first composition (a) and at least one second composition (b). The layers (9a, 9b) of the superlattice (9) contain dopants in predetermined concentrations, with regard to which the concentrations of the dopants are different at least two layers of a same composition in the superlattice (9), the concentration of the dopants is graded within at least one layer (9a, 9b) of the superlattice (9), and the superlattice (9) comprises layers that are doped with different dopants or comprise at least one layer (9a, 9b) that is undoped. The electrical and optical properties of the superlattice (9) can be adapted to given requirements in the best possible manner in this way.

Abstract: A laser diode comprising a first separate confinement heterostructure and an active region on the first separate confinement heterostructure. A second separate confinement heterostructure is on the active region and one or more epitaxial layers is on the second separate confinement heterostructure. A ridge is formed in the epitaxial layers with a first mesa around the ridge. The first mesa is 0.1 to 0.2 microns above the second confinement heterostructure.

Abstract: In a conventional EA/DFB laser, since the temperature dependence of the operation wavelength of the EA portion is substantially different from that of the DFB portion, the temperature range over which a stable operation is possible is small. In the case of using the EA/DFB laser as a light emission device, an uncooled operation is not possible. An EA/DFB laser which does not require a temperature control mechanism is proposed. A quantum well structure in which a well layer made of any one of InGaAlAs, InGaAsP, and InGaAs, and a barrier layer made of either one of InGaAlAs or InAlAs is used for an optical absorption layer of an EA modulator. By properly determining detuning at a temperature of 25° C. and a composition wavelength of the barrier layer in the quantum well structure used for the optical absorption layer, it can be realized to suppress the insertion loss, maintain the extinction ratio, and reduce chirping simultaneously over a wide temperature range from ?5° C. to 80° C.

Abstract: A semiconductor device comprises an n-side waveguide layer, an active layer in contact with the n-side waveguide layer and a p-side waveguide layer in contact with the active layer. An electron blocking layer is in contact with the p-side waveguide layer and comprises a first composition of two elements from group III of the periodic table and an element from group V of the periodic table. A cladding layer includes a cladding sublayer that is in contact with the electron blocking layer. The cladding sublayer comprises a second composition of two elements from group III of the periodic table and an element from group V of the periodic table. The second composition is different from the first composition.

Abstract: A gallium nitride based semiconductor laser device comprises: a first cladding layer having a first conductivity type; an active layer provided on the first cladding layer; an overflow prevention layer having a second conductivity type provided on the active layer; and a second cladding layer having the second conductivity type provided on the overflow prevention layer. The second cladding layer has a ridge portion and a non-ridge portion, and is made of an AlxGa1-xN (0.015?x?0.040). Alternatively, the second cladding layer has a superlattice layer of AlyGa1-yN (0.015?y?1) layers and GaN layers with an average aluminum composition ratio of 0.015 or more and 0.040 or less. A thickness of the ridge portion is not less than a thickness of the non-ridge portion and not more than 0.45 micrometers.

Abstract: A semiconductor laser includes a columnar lamination structure including a first multi-layer reflection mirror, a first spacer layer, an AlxGayIn1-x-yP (where 0?x<1 and 0<y<1) based active layer, a second spacer layer, a second multi-layer reflection mirror, and a lateral mode adjusting layer on a substrate in this order from the substrate and including a current narrowing layer. The current narrowing layer includes an unoxidized region in an in-plane central region and a circular oxidized region in the circumference of the unoxidized region. The later mode adjusting layer includes a high reflection region to correspond to the unoxidized region and a circular low reflection region in the circumference of the high reflection region. On the assumption that a diameter of the unoxidized region is Dox and a diameter of the high reflection region is Dhr, the diameters Dox and Dhr satisfy an expression of 0.8<Dhr/Dox<1.5.

Abstract: A semiconductor laser structure includes: a plurality of laser structure units, wherein each laser structure unit includes a N conductive type clad layer, a light emission layer and a P conductive type clad layer, which are stacked in this order; and a tunnel junction layer disposed between two adjacent laser structure units. The tunnel junction layer includes a P conductive type layer and a N conductive type layer. The P conductive type layer includes a dopant of zinc. The N conductive type layer includes a dopant of a group six element.

Abstract: A nitride semiconductor laser device has a group III nitride semiconductor multilayer structure. The group III nitride semiconductor multilayer structure includes an n-type semiconductor layer, a p-type semiconductor layer and a light emitting layer held between the n-type semiconductor layer and the p-type semiconductor layer, and the p-type semiconductor layer is formed by successively stacking a p-side guide layer, a p-type electron blocking layer in contact with the p-side guide layer and a p-type cladding layer in contact with the p-type electron blocking layer from the side closer to the light emitting layer. The p-side guide layer is formed by stacking a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.

Abstract: An object of the invention is to achieve a high output gain waveguide semiconductor laser device exhibiting high reliability by suppressing growth of <100>DLD. A semiconductor laser device includes a semiconductor laser structure of a gain waveguide formed on a semiconductor substrate in which two grooves extending in an oscillation direction thereof are formed, wherein a current injection stripe is arranged between the two grooves. Preferably, a quantum well constituting an active layer of the semiconductor laser device is composed of GaAs.

Abstract: The present invention provides a semiconductor laser including a first conductive type of a lower clad layer 12, an active layer 14 provided on the lower clad layer 12, the active layer 14 including a plurality of quantum dots, and a second conductive type of an upper clad layer 18, the upper clad layer 18 being provided on the active layer 14 so as to have an isolated ridge portion 30 such that W1?Wtop+0.4 ?m where Wtop is the width of a top of the ridge portion 30 and W1 is the width of the ridge portion 30 at a height of 50 nm from a bottom of the ridge portion 30. The present invention also provides a method for manufacturing such a semiconductor laser.

Abstract: The invention relates to a quantum cascade device of detector type comprising two electrodes for applying a control electrical field, and a waveguide positioned between the two electrodes, said device comprising a gain region made up of a plurality of layers and comprising alternating strata of a first type each defining a quantum barrier and strata of a second type each defining a quantum well, each layer of the gain region comprising an injection barrier exhibiting an injection subband of charge carriers with a lower energy level called injector level (i) and an active area, said active area being made of a set of pairs of strata made from semiconductive materials so that each of the wells has at least one upper subband called third subband (3), a middle subband called second subband (2) and a bottom subband called first subband (1), the potential difference between the third and second subbands being such that the transition of an electron from the third subband to the second subband emits an energy corres

Abstract: A semiconductor laser device has a semiconductor laser diode structure made of group III nitride semiconductors having major growth surfaces defined by nonpolar planes or semipolar planes. The semiconductor laser diode structure includes a p-type cladding layer and an n-type cladding layer, a p-type guide layer and an n-type guide layer held between the p-type cladding layer and the n-type cladding layer, and an active layer containing In held between the p-type guide layer and the n-type guide layer. The In compositions in the p-type guide layer and the n-type guide layer are increased as approaching the active layer respectively. Each of the p-type guide layer and the n-type guide layer may have a plurality of InxGa1-xN layers (0?x?1). In this case, the plurality of InxGa1-xN layers may be stacked in such order that the In compositions therein are increased as approaching the active layer.

Abstract: A laser diode and method for fabricating same, wherein the laser diode generally comprises an InGaN compliance layer on a GaN n-type contact layer and an AlGaN/GaN n-type strained super lattice (SLS) on the compliance layer. An n-type GaN separate confinement heterostructure (SCH) is on said n-type SLS and an InGaN multiple quantum well (MQW) active region is on the n-type SCH. A GaN p-type SCH on the MQW active region, an AlGaN/GaN p-type SLS is on the p-type SCH, and a p-type GaN contact layer is on the p-type SLS. The compliance layer has an In percentage that reduces strain between the n-type contact layer and the n-type SLS compared to a laser diode without the compliance layer. Accordingly, the n-type SLS can be grown with an increased Al percentage to increase the index of refraction. This along with other features allows for reduced threshold current and voltage operation.

Abstract: An optical diode structure includes a semiconductor substrate, a luminous layer, a first type semiconductor layer and a second type semiconductor. The luminous layer is disposed over the semiconductor substrate for emitting light. The first type semiconductor layer is formed between the semiconductor substrate and the luminous layer. The second type semiconductor layer has a first surface and a second surface. The first surface is in contact with the luminous layer. A rough-surfaced grating structure is formed in the second surface for modulating the light emitted by the luminous layer, thereby increasing light extraction efficiency of the luminance layer.

Abstract: An interband resonant tunneling intersubband transition laser is disclosed, and includes a semiconductor substrate, and a first cladding layer, an active region structure layer and a second cladding layer formed on the semiconductor substrate. The active region structure layer includes quantum well layers and quantum barrier layers that are alternately stacked and have a broken energy bandgap. Thus, the interband resonant tunneling intersubband transition laser operates in a cascade mode in which an intersubband radiative transition and interband tunneling of carriers consecutively and repetitively occur in the active region structure layer, and thus can achieve a high output from a simple, compact structure.

Abstract: A nitride semiconductor laser device includes: a substrate made of silicon in which a plane orientation of a principal surface is a {100} plane; and a semiconductor laminate that includes a plurality of semiconductor layers formed on the substrate and includes a multiple quantum well active layer, each of the plurality of semiconductor layers being made of group III-V nitride. The semiconductor laminate has a plane parallel to a {011} plane which is a plane orientation of silicon as a cleavage face and the cleavage face constructs a facet mirror.

Abstract: A semiconductor light-emitting device includes a substrate, a first cladding layer over the substrate, an active region on the first cladding layer, and a second cladding layer on the active region, wherein the active region includes a first type barrier layer that is doped and a second type barrier layer that is undoped, the first type barrier layer being closer to the first cladding layer than the second type barrier layer.

Abstract: The present invention provides a laser diode having both a small vertical far-field beam divergence and a large vertical optical confinement factor, as well as a method of fabricating the laser diode. The laser diode comprises a layer stack of semiconductor material, which includes a mode-splitting layer having a low refractive index inserted between waveguide layers. In addition to increasing the vertical near-field beam width of the laser diode, the mode-splitting layer also produces a shoulder in an optical mode generated in an active layer of the layer stack, increasing vertical overlap of the optical mode with the active layer.

Abstract: A laser diode epitaxial wafer includes an n-type GaAs substrate, an n-type cladding layer formed on the n-type GaAs substrate, an active layer formed on the n-type cladding layer, and a p-type cladding layer formed on the active layer. The n-type cladding layer, the active layer, and the p-type cladding layer include an AlGaInP-based material. The p-type cladding layer has carbon as a p-type impurity. The p-type cladding layer has a carrier concentration between 8.0×1017 cm?3 and 1.5×1018 cm?3.

Abstract: Semiconductor structures and devices based thereon include an aluminum nitride single-crystal substrate and at least one layer epitaxially grown thereover. The epitaxial layer may comprise at least one of AlN, GaN, InN, or any binary or tertiary alloy combination thereof, and have an average dislocation density within the semiconductor heterostructure is less than about 106 cm?2.

Abstract: A surface-emission laser diode comprises a cavity region over a semiconductor substrate and includes an active layer containing at least one quantum well active layer producing a laser light and a barrier layer, a spacer layer is provided in the vicinity of the active layer and formed of at least one material, an upper and lower reflectors are provided at a top part and a bottom part of the cavity region, the cavity region and the upper and lower reflectors form a mesa structure over the semiconductor substrate, the upper and lower reflectors being formed of a semiconductor distributed Bragg reflector having a periodic change of refractive index and reflecting incident light by interference of optical waves, at least a part of the semiconductor distributed Bragg reflector is formed of a layer of small refractive index of AlxGa1-xAs (0<x?1) and a layer of large refractive index of AlyGa1-yAs (0?y<x?1), the lower reflector is formed of a first lower reflector having a low-refractive index layer of AlAs an

Abstract: A quantum cascade laser includes a semiconductor substrate, and an active layer which is provided on the semiconductor substrate, and has a cascade structure in which unit laminate structures 16 having quantum well emission layers 17 and injection layers 18 are laminated in multiple stages. Further, the quantum cascade laser is configured such that the unit laminate structure 16 has an emission upper level Lup, an emission lower level Llow, and a relaxation miniband MB including an energy level lower than the emission lower level in its subband level structure, and light is generated by an intersubband transition of electrons from the upper level to the lower level, and the electrons after the intersubband transition are relaxed from the lower level Llow to the miniband MB through LO phonon scattering, to be injected from the injection layer 18 to the latter stage emission layer via the miniband MB.

Abstract: A gain medium and an interband cascade laser, an interband cascade amplifier, and an external cavity laser having the gain medium are presented.

Abstract: A nitride semiconductor device include an n-type nitride semiconductor layer; a p-type nitride semiconductor layer; and an active layer formed between the n-type and p-type nitride semiconductor layers. The active layer has an alternately-layered structure of a plurality of quantum well layers and a plurality of quantum barrier layers, each alternately stacked on each of the quantum well layers. The alternately-layered structure includes a unit multi-layer structure and a thick quantum barrier well. The unit multi-layer structure includes a first quantum well layer, a second quantum well layer formed, a tunneling quantum barrier layer and a crystal quality-improving layer. The thick quantum barrier well may be formed adjacent to the first and second quantum well layers, with a thickness thereof greater than that of the first and second quantum well layers.

Abstract: In a method for the production of a single photon source with a given operational performance, the given operational performance for the individual photon source may be fixed by a directed setting of the fine structure gap of the excitonic energy level for at least one quantum dot. The at least one quantum dot is produced with a quantum dot size corresponding to the fine structure gap for setting.

Abstract: An improved VECSEL device is provided in which the gain of each of the quantum well layers can be increased in a periodic gain structure. A vertical external cavity surface emitting laser (VECSEL) device comprising: a substrate; a bottom DBR mirror formed on the substrate; a multiple quantum well layer formed on the bottom DBR mirror and comprising: a plurality of quantum well layers; first and second strain compensation layers sequentially formed above and below each of the quantum well layers to gradually relieve the strain of the quantum well layers; a capping layer formed on the multiple quantum well layer; an optical pump radiating a pump beam to the surface of the capping layer; and an external cavity mirror separated from and facing the bottom DBR mirror.

Abstract: Vertical cavity surface emitting lasers are disclosed, one example of which includes a substrate upon which a lower mirror layer is formed. An active region and upper mirror layer are disposed, in that order, on the lower mirror layer. In particular, the upper mirror layer includes a plurality of DBR layers formed on the active region. The upper mirror layer additionally includes a photonic crystal formed on the plurality of DBR layers and having a periodic structure that contributes to the definition of a central defect. As a consequence of this structure, the photonic crystal has a reflectivity that is wavelength dependent, and the central defect enables the VCSEL to propagate a single mode.

Abstract: The present invention provides a semiconductor device including: a semiconductor layer including an n-type first cladding layer, an n-type second cladding layer, an active layer, a p-type first cladding layer, and a p-type second cladding layer in this order on an InP substrate. The n-type first cladding layer and the n-type second cladding layer satisfy formulas (1) to (4) below, or the p-type first cladding layer and the p-type second cladding layer satisfy formulas (5) to (8) below.

Abstract: Optoelectronic devices are provided. In one embodiment, a device may include a first conductivity type cladding layer including a first barrier layer, an active layer formed on the first conductivity-type cladding layer, the active layer including a well layer made of a nitride semiconductor, and a second conductivity-type cladding layer formed on the active layer and including a second barrier layer. The active layer is positioned between and adjacent to the first barrier layer and the second barrier layer.

Abstract: A nitride semiconductor laser diode includes: a substrate made of silicon in which a plane orientation of a principal surface is a {100} plane; and a semiconductor that includes a plurality of semiconductor layers formed on the substrate and including an active layer, each of the plurality of semiconductor layers being made of group III nitride. The semiconductor has a plane parallel to a {011} plane which is a plane orientation of silicon as a cleaved facet, the cleaved facet forming a facet mirror.

Abstract: A n-type layer, a multiquantum well active layer comprising a plurality of pairs of an InGaN well layer/InGaN barrier layer, and a p-type layer are laminated on a substrate to provide a nitride semiconductor light emitting element. A composition of the InGaN barrier included in the multiquantum well active layer is expressed by InxGa1-xN (0.04?x?0.1), and a total thickness of InGaN layers comprising an In composition ratio within a range of 0.04 to 0.1 in the light emitting element including the InGaN barrier layers is not greater than 60 nm.

Abstract: The present invention provides a ring laser system comprising forming an optical core by an epitaxial layer overgrowth over an intermediate layer, forming multi-quantum wells adjacent to the optical core and forming an outer structure further comprising a total internal reflector, wherein forming photons within the multi-quantum wells further comprises circulating the photons within the ring laser structure comprising the outer structure, the multi-quantum wells, and the optical core.

Abstract: A semiconductor laser using a nitride type Group III-V compound semiconductor includes: an n-side clad layer; an n-side optical waveguide layer over the n-side clad layer; an active layer over the n-side optical waveguide layer; a p-side optical waveguide layer over the active layer; an electron barrier layer over the p-side optical waveguide layer; and a p-side clad layer over the electron barrier layer. A ridge stripe is formed at an upper part of the p-side optical waveguide layer, the electron barrier layer and the p-side clad layer, and the distance between the electron barrier layer and a bottom surface in areas on both sides of the ridge stripe is not less than 10 nm.

Abstract: An edge-emitting semiconductor optical device comprises a first cladding layer, an active layer, and a second cladding layer. The first cladding layer is provided on a semiconductor substrate. The active layer is provided on the first cladding layer. The semiconductor substrate has a higher band gap than that of the active layer. The first cladding layer includes a first light-absorbing layer and a first light-transmitting layer. The first light-absorbing layer has a lower band gap than that of the active layer, and the first light-transmitting layer has a higher band gap than that of the active layer. The second cladding layer is provided on the active layer.

Abstract: Electrically pumped mid-IR semiconductor lasers that are operable at room temperature and possess a range of tunability up to 1100 nm, which constitutes a revolutionary (1-2 orders of magnitude) improvement in the range of tunability over existing semiconductor laser technology utilizing Doped quantum confined host material (DQCH) with characteristic spatial dimension of the confinement tuned to enable the overlap of the discrete levels of the host and impurity ions and efficient energy transfer from the separated host carriers to the impurity, wherein: said DQCH material has the formula TM:MeZ and/or MeX2Z4, wherein Me is selected from the group consisting of Zn, Cd, Ca, Mg, Sr, Ba, Hg, Pb, Cu, Al, Ga, In; Z is selected from the group consisting of S, Se, Te, O, N, P, As, Sb and their mixtures; X being selected from the group consisting of Ga, In, and Al; and TM is selected from the group consisting from V, Cr, Mn, Fe, Co, and Ni.

Abstract: Provided are a quantum dot laser diode and a method of manufacturing the same. The method of manufacturing a quantum dot laser diode includes the steps of: forming a grating structure layer including a plurality of gratings on a substrate; forming a first lattice-matched layer on the grating structure layer; forming at least one quantum dot layer having at least one quantum dot on the first lattice-matched layer; forming a second lattice-matched layer on the quantum dot layer; forming a cladding layer on the second lattice-matched layer; and forming an ohmic contact layer on the cladding layer. Consequently, it is possible to obtain high gain at a desired wavelength without affecting the uniformity of quantum dots, so that the characteristics of a laser diode can be improved.

Abstract: Provided are a process for producing a nitride semiconductor laser that is a process applied to materials wherein a diffusion of an impurity is not easily attained, such as nitride semiconductor material, and substituted for any process including the step of local diffusion of an impurity, which has been hitherto carried out for GaAlAs based or AlGaInP based semiconductors, and that is a process which is effective, high in precision, and suitable for mass production; and a nitride semiconductor laser produced by this process. The nitride-semiconductor-producing process of the present invention includes the steps of: preparing a substrate having an MQW active layer made of a nitride semiconductor containing In; irradiating a vicinity of a light-emitting end face of the multiquantum well active layer, or a planned region of the light-emitting end face selectively with a laser beam; and performing heating treatment after the laser-irradiating step.

Abstract: A semiconductor laser diode comprises a p-n junction. The p-n junction comprises a substrate, an n-type semiconductor layer, a p-type semiconductor layer, and a quantum well. The quantum well is disposed between the n-type semiconductor layer and the p-type semiconductor layer. The substrate is formed from a first material system, the n-type semiconductor layer is formed from a second material system, the p-type semiconductor layer is formed from a third material system, and the quantum well is formed from a fourth material system. The second material system is different from the third material system. The second material system and the third material system are selected such that there is an increase in the rate of recombinations of the electrons from the n-type semiconductor layer and the holes from the p-type semiconductor layer in the quantum well. This results in a lower turn-on voltage for the semiconductor laser diode.

Abstract: The present invention provides a core/multishell semiconductor nanocrystal comprising a core and multiple shells, which exhibits a type-I band offset and high photoluminescence quantum yield providing bright tunable emission covering the visible range from about 400 nm to NIR over 1600 nm.

Abstract: Structures and methods for electronic devices with improved conductive regions are provided. The conductive region may include digital alloy superlattice structures, which allow higher doping levels to be achieved than for a bulk (random) alloy with the same average composition. Furthermore, the superlattice structures may improve the resistivity of the region, improving the current spreading of the region and hence the electronic properties of electronic devices such as optoelectronic devices.

Abstract: A quantum cascade laser utilizing non-resonant extraction design having a multilayered semiconductor with a single type of carrier; at least two final levels (1 and 1?) for a transition down from level 2; an energy spacing E21 greater than ELO; an energy spacing E31 of about 100 meV; and an energy spacing E32 about equal to ELO. The carrier wave function for level 1 overlaps with the carrier wave function for level 2. Likewise, the carrier wave function for level 1? overlaps with the carrier wave function for level 2. In a second version, the basic design also has an energy spacing E54 of about 90 meV, and levels 1 and 1? do not have to be spatially close to each other, provided that level 2 has significant overlap with both these levels. In a third version, there are at least three final levels (1, 1?, and 1?) for a transition down from level 2. Each of the levels 1, 1?, and 1? has a non-uniform squared wave function distribution.

Abstract: A semiconductor laser and light emitting device is defined. The device comprises an electron injector and an active region adjacent to the electron injector. The active region includes at least one deep quantum well with barrier layers adjacent to either side of the quantum well or wells such that electrons injected from the electron injector into a high energy level of the quantum well relax to a lower energy level with the emission of a photon and are transmitted out to a region beyond the last barrier layer of the active region. The electron injector includes quantum well layers. The bottom of each deep quantum well or wells in the active region is lower in energy than the bottoms of the quantum well layers in the electron injector. The device may further comprise at least two stages wherein each stage contains an electron injector and an active region.

Abstract: A semiconductor laser and a method of forming the same are provided. The n-side and p-side junctions are independently optimized to improve carrier flow. The material for the n-side cladding layer is selected to yield a small conduction to valance band gap offset ratio while the material for the p-side cladding layer is selected to yield a large conduction to valance band gap offset ratio.