4263 results about "Quantum well" patented technology

A yellow Light Emitting Diode (LED) with a peak emission wavelength in the range 560-580 nm is disclosed. The LED is grown on one or more III-nitride-based semipolar planes and an active layer of the LED is composed of indium (In) containing single or multi-quantum well structures. The LED quantum wells have a thickness in the range 2-7 nm. A multi-color LED or white LED comprised of at least one semipolar yellow LED is also disclosed.

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.

Provided is a semiconductor opto-electronic device that may comprise an active layer including a quantum well and a barrier layer on a substrate, upper and lower waveguide layers on and underneath the active layer, respectively, and upper and lower clad layers on and underneath the upper and lower waveguide layers, respectively. The semiconductor opto-electronic device may further comprise an upper optical confinement layer (OCL) between the active layer and the upper waveguide layer and having an energy gap smaller than the energy gap of the upper waveguide layer and equal to or larger than the energy gap of the barrier layer, and a lower OCL between the active layer and the lower waveguide layer and having an energy gap smaller than the energy gap of the lower waveguide layer and equal to or smaller than the energy gap of the barrier layer. Also provided is a method of fabricating the semiconductor opto-electronic device.

In a semiconductor laser having an active layer of double-quantum-well structure that includes two InGaN well layers each of which has a thickness of 5 nm, a threshold current deteriorates to a relatively small degree while differential efficiency is improved considerably in a region having a light confinement coefficient Γ of 3.0% or less. On the other hand, with the light confinement coefficient Γ becoming less than 1.5%, the threshold current increases considerably while the amount of improvement in differential efficiency becomes small. It is therefore preferable that the lowest limit to the light confinement coefficient Γ be about 1.5%. The differential efficiency of 1.6 W/A or more is obtained with the light confinement coefficient Γ being 3.0% or less, and the differential efficiency of 1.7 W/A or more is obtained with the light confinement coefficient Γ being 2.6% or less.

A flash memory device includes a floating gate made of a multi-layered structure. The floating gate includes a hetero-pn junction which serves as a quantum well to store charge in the floating gate, thus increasing the efficiency of the device, allowing the device to be operable using lower voltages and increasing the miniaturization of the device. The floating gate may be used in n-type and p-type devices, including n-type and p-type fin-FET devices. The stored charge may be electrons or holes.

A nitride semiconductor light-emitting device includes an emission layer (103) formed on a substrate (100), and the emission layer includes a quantum well layer of GaN_1-x−y−zAs_xP_ySb_z (0<x+y+z≦0.3) containing Al.

Disclosed is a multi-quantum-well light emitting diode, which makes enormous adjustments and improvements over the conventional light emitting diode, and further utilizes a transparent contact layer of better transmittance efficiency, so as to significantly raise the illuminance of this light emitting diode and its light emission efficiency. The multi-quantum-well light emitting diode has a structure including: substrate, buffer layer, n-type gallium-nitride layer, active light-emitting-layer, p-type cladding layer, p-type contact layer, barrier buffer layer, transparent contact layer, and the n-type electrode layer.

A method for fabricating Al_xGa_1-xN-cladding-free nonpolar III-nitride based laser diodes or light emitting diodes. Due to the absence of polarization fields in the nonpolar crystal planes, these nonpolar devices have thick quantum wells that function as an optical waveguide to effectively confine the optical mode to the active region and eliminate the need for Al-containing waveguide cladding layers.

A semiconductor light emitting device is disclosed, including a semiconductor substrate, an active region comprising a strained quantum well layer, and a cladding layer for confining carriers and light emissions, wherein the amount of lattice strains in the quantum well layer is in excess of 2% against either the semiconductor substrate or cladding layer and, alternately, the thickness of the quantum well layer is in excess of the critical thickness calculated after Matthews and Blakeslee.

A method and system for providing an energy assisted magnetic recording (EAMR) disk drive are described. The EAMR disk drive includes a media, a slider having a trailing face, at least one EAMR head on the slider, and at least one vertical surface emitting laser (VCSEL). The VCSEL(s) includes a plurality of quantum wells and an extended resonance cavity. The VCSEL(s) provides energy to the EAMR disk drive. The extended resonance cavity extends into the slider and is oriented substantially perpendicular to the trailing face of the slider. The EAMR head(s) include grating(s), waveguide(s), a write pole, and coil(s) for energizing the write pole. At least a portion of the grating(s) reside in the extended resonance cavity and couple energy from the VCSEL to the waveguide(s). The waveguide(s) direct the energy from the grating(s) toward the media.

A transistor with improved device characteristics includes a substrate, a first buffer layer deposited on the substrate, a highly resistive epilayer deposited on the buffer layer, a second epilayer deposited on the highly resistive epilayer, a channel layer deposited on the second epilayer, an AlGaN alloy epilayer deposited on the channel layer, and source, gate, and drain connections deposited on the AlGaN alloy epilayer. The highly resistive epilayer may include AlGaN, InAlGaN, AlBN, or AlN compositions. The channel layer may include InGaN, graded InGaN, multilayers of InGaN and GaN, or GaN.

In a semiconductor device, concave sections in which an opening area becomes small in proportion as a depth becomes deep are formed in a crystal layer, and a quantum structure is formed on at least one crystal face of a bottom section of the concave section and a border formed between plural sidewalls thereof. In case the quantum structure is formed in the bottom section, a quantum box is formed therein. If the quantum structure is formed in the border between the sidewalls of the concave section, a quantum wire is formed therein. In case the quantum structure is formed in the sidewall of the concave section, a two-dimensional quantum well is formed therein.

Concaves and convexes 1a are formed by processing the surface layer of a first layer 1, and second layer 2 having a different refractive index from the first layer is grown while burying the concaves and convexes (or first crystal 10 is grown as concaves and convexes on crystal layer S to be the base of the growth, and second crystal 20 is grown, which has a different refractive index from the first crystal). After forming these concavo-convex refractive index interfaces 1a (10a), an element structure, wherein semiconductor crystal layers containing a light-emitting layer A are laminated, is formed. As a result, the light in the lateral direction, which is generated in the light-emitting layer changes its direction by an influence of the concavo-convex refractive index interface and heads toward the outside. Particularly, when an ultraviolet light is to be emitted using InGaN as a material of a light-emitting layer, a quantum well structure is employed and all the layers between the quantum well structure and the low temperature buffer layer are formed of a GaN crystal, removing AlGaN. The quantum well structure preferably consists of a well layer made of InGaN and a barrier layer made of GaN, and the thickness of the barrier layer is preferably 6 nm–30 nm.

Light sources are disclosed. A disclosed light source includes a III-V based pump light source (170) that includes nitrogen and emits light at a first wavelength. The light source further includes a vertical cavity surface emitting laser (VCSEL) that converts at least a portion of the first wavelength light (174) emitted by the pump light source (170) to at least a partially coherent light at a second wavelength (176). The VCSEL includes first and second mirrors (120, 160) that form an optical cavity for light at the second wavelength. The first mirror (120) is substantially reflective at the second wavelength and includes a first multilayer stack. The second mirror (160) is substantially transmissive at the first wavelength and partially reflective and partially transmissive and the second wavelength. The second mirror includes a second multilayer stack. The VCSEL further includes a semiconductor multilayer stack (130) that is disposed between the first and second mirrors and converts at least a portion of the first wavelength light to the second wavelength light. The semiconductor multilayer stack (130) includes a quantum well that includes a Cd(Mg)ZnSe alloy.

A semiconductor light-emitting device involving the steps of: forming a first semiconductor layer; forming a light-emitting layer of superlattice structure by laminating a barrier layer being made of InY1Ga1-Y1N (Y1>/=0) and a quantum well layer being made of InY2Ga1-Y1N (Y2>Y1 and Y2>0) on the first semiconductor layer; and forming a second semiconductor layer on the light-emitting layer, an uppermost barrier layer, which will become an uppermost layer of the light-emitting layer, is made thicker than the other barrier layers. Further, at the time of forming the second semiconductor layer, an upper surface of such uppermost barrier layer is caused to disappear so that the thickness of the uppermost barrier layer becomes substantially equal to those of the other barrier layers.

An improved nitride-based light emitting heterostructure is provided. The nitride-based light emitting heterostructure includes an electron supply layer and a hole supply layer with a light generating structure disposed there between. The light generating structure includes a set of barrier layers, each of which has a graded composition and a set of quantum wells, each of which adjoins at least one barrier layer. Additional features, such as a thickness of each quantum well, can be selected/incorporated into the heterostructure to improve one or more of its characteristics. Further, one or more additional layers that include a graded composition can be included in the heterostructure outside of the light generating structure. The graded composition layer(s) cause electrons to lose energy prior to entering a quantum well in the light generating structure, which enables the electrons to recombine with holes more efficiently in the quantum well.

A semiconductor device comprises an active layer having a quantum well structure, the active layer including a well layer and a barrier layer and being sandwiched by a first conductivity type layer and a second conductivity type layer, wherein a first barrier layer is provided on side of the first conductivity type layer in the active layer and a second barrier layer is provided on the side of the second conductivity type layer in the active layer, at least one well layer is sandwiched thereby, and the second barrier layer has a band gap energy lower than that of the first barrier layer in the form of asymmetric barrier layer structure, where the second conductivity type layer preferably includes a carrier confinement layer having a band gap energy higher than that of the first barrier layer, resulting in a reverse structure in each of conductivity type layer in respect to the asymmetric structure of the active layer to provide a waveguide structure having excellent crystallinity and device characteristics in the nitride semiconductor light emitting device operating at a wavelength of 380 nm or shorter.

Photonic integrated circuits on silicon are disclosed. By bonding a wafer of compound semiconductor material as an active region to silicon and removing the substrate, the lasers, amplifiers, modulators, and other devices can be processed using standard photolithographic techniques on the silicon substrate. A silicon laser intermixed integrated device in accordance with one or more embodiments of the present invention comprises a silicon-on-insulator substrate, comprising at least one waveguide in a top surface, and a compound semiconductor substrate comprising a gain layer, the compound semiconductor substrate being subjected to a quantum well intermixing process, wherein the upper surface of the compound semiconductor substrate is bonded to the top surface of the silicon-on-insulator substrate.

Photodetectors and integrated circuits including photodetectors are disclosed. A photodetector in accordance with the present invention comprises a silicon-on-insulator (SOI) structure resident on a first substrate, the SOI structure comprising a passive waveguide, and a III-V structure bonded to the SOI structure, the III-V structure comprising a quantum well region, a hybrid waveguide, coupled to the quantum well region and the SOI structure adjacent to the passive waveguide, and a mesa, coupled to the quantum well region, wherein when light passes through the hybrid waveguide, the quantum well region detects the light and generates current based on the light detected.

An LED chip and method of fabricating the same is disclosed that comprises a plurality of sub-LEDs, said sub-LEDs interconnected such that the voltage necessary to drive said sub-LEDs is dependent on the number of said interconnected sub-LEDs and the junction voltage of said sub-LEDs. Each of said interconnected sub-LEDs comprising an n-type semiconductor layer, a p-type semiconductor layer, and an active or quantum well region interposed between the n-type and p-type layers. The monolithic LED chip further comprising a p-electrode having a lead that is accessible from a point on a surface opposite of a primary emission surface of the monolithic LED chip, the p-electrode electrically connected to the p-type layer, and an n-electrode having a lead that is accessible from a point on the surface opposite of the primary emission surface, the n-electrode electrically connected to the n-type layer. These sub-LEDs interconnected by at least a metallization layer on the n-type and p-type layers, which is insulated so that it does not short the sub-LEDs. Further, the LED chip is capable of being electrically coupled for operation without wire bonds.

A solar cell device includes a p-n diode component over a substrate, the p-n diode component including at least one subcell, each subcell including an n-type semiconductor layer and a p-type semiconductor layer to form a p-n junction. The solar cell device further includes at least two features selected from: i) a nano-structured region between at the p-n junction of at least one subcell; ii) an n-type and/or a p-type layer of at least one subcell that includes a built-in quasi-electric field; and iii) a photon reflector structure. Alternatively, the solar cell device includes at least two subcells, and further includes a nano-structured region at the p-n junction of at least one of the subcells, wherein the subcells of the solar cell device are connected in parallel to each other by the p-type or the n-type semiconductor layer of each subcell. Alternatively, the solar cell device further includes a nano-structured region at the p-n junction of at least one subcell, wherein the nano-structured region includes i) a plurality of quantum dots or quantum wells that include InN or InGaN, the quantum dots or quantum wells embedded within a wide band gap matrix that includes InGaN, GaN, or AlGaN, or ii) a plurality of quantum dots or quantum wells that include InAs, GaAs or InGaAs, the quantum dots or quantum wells embedded within a wide band gap matrix that includes InGaP, GaAsP, AlGaAs, AlGaInAs or AlGaInP.