Abstract: A MWIR laser is provided having a novel n-type superlattice cladding layer comprising either InAs/AlAs.sub.0.16 Sb.sub.0.84 or In.sub.x Ga.sub.y Al.sub.1-x-y As/AlSb. The n-type superlattice cladding layer may comprise a Si selectively-doped (SD) InAs/AlAs.sub.0.16 Sb.sub.0.84 short-period superlattice (SPS) lattice-matched to an InAs substrate or a Si SD In.sub.x Ga.sub.y Al.sub.1-x-y As/AlSb SPS lattice-matched to a GaSb or InAs substrate. The advantages of the Si SD InAs/AlAs.sub.0.16 Sb.sub.0.84 SPS and Si SD In.sub.x Ga.sub.y Al.sub.1-x-y As/AlSb SPS include: (1) large dynamic range in the electron concentration in the Si-doped n-type cladding layer; and (2) strong hole confinement in the active region. Furthermore, the novel n-type superlattice cladding layer can be deposited without the use of tellurium (Te) which is not a preferred source material for MBE growth of III-V semiconductors.

Abstract: To provide a Schottky junction device having a super-lattice arranged in the Schottky interface in order to secure a high Schottky barrier and at the same time showing a high speed response by resolving the phenomenon of piled-up holes at the upper edge of the valence band, while maintaining the height of the Schottky barrier. A Schottky junction device having a Schottky junction of a semiconductor and a metal and a superlattice on the interface of the semiconductor and the metal, wherein the upper edge of the valence band of said superlattice is varied to show a turn to a specific direction. The phenomenon of hole-piling up at the upper end of the valence band is resolved while maintaining the height of the Schottky barrier and consequently such a Schottky junction device shows an excellent high speed response.

Abstract: A thermoelectric element having a very large number of alternating layers of semiconductor material. The alternating layers all have the same crystalline structure. The inventors have demonstrated that materials produced in accordance with this invention provide figures of merit more than six times that of prior art thermoelectric materials. A preferred embodiment is a superlattice of Si, as a barrier material, and SiGe, as a conducting material, both of which have the same cubic structure. Another preferred embodiment is a superlattice of B--C alloys, the layers of which would be different stoichiometric forms of B--C but in all cases the crystalline structure would be alpha 0. In a preferred embodiment the layers are grown under conditions as to cause them to be strained at their operating temperature range in order to improve the thermoelectric properties.

Abstract: A heterojunction semiconductor device includes an unipolar transistor having, a collector layer, a base layer, a collector side barrier layer provided between the collector layer and base layer, an emitter layer, and an emitter side barrier layer provided between the base layer and the emitter layer. The emitter side barrier layer has a thickness for tunneling a carrier from the emitter and base layer and injecting the carrier into the base layer according to a predetermined voltage applied between the emitter and base layers, the base layer includes a superlattice structure. The superlattice structure includes a plurality thin barrier layers and a thin well layer for forming a mini-band through which the injected carrier can move and a mini-band gap with which the injected carrier collides.

Abstract: A quantum bridge structure including wires of a semiconductor material such as silicon which are formed by selectively etching a superlattice of alternating layers of at least two semiconductor materials. The quantum bridge is useful as a photo emission device, a photo detector device, and a chemical sensor. The wires exhibit improved electrical conduction properties due to decreased Coulomb scattering.

Abstract: An organic semiconductor including an organic semiconductor layer, which layer is formed by epitaxially depositing molecules of a compound selected from phthalocyanines to form a super-thin film configuration including one-dimensional columns of stacked molecules in the form of quantum wires separated respectively from each other.

Abstract: In a light emitting device made of a group II-VI semiconductor of ZnCdSSe or MgZnCdSSe, to facilitate the movement of electrons or holes from a GaAs substrate to a group II-VI semiconductor film and to flow the current at a low voltage, a ZnSe--AlGaAs super lattice layer is formed between the group II-VI semiconductor film and the GaAs substrate so that the energy band from the substrate to the group II-VI semiconductor film rises in steps or gradually. In an device where an N-type semiconductor layer of the group II-VI semiconductor film is arranged on the side of the substrate, a P-type semiconductor film which raises the energy band from the electrode to the P-type semiconductor layer in steps is formed between the electrode and the P-type semiconductor layer which is the top layer of the group II-VI semiconductor film.

Abstract: A quantum box array comprising a plurality of quantum boxes is made by providing a plurality of box-shaped quantum well portions on a first barrier layer and a second barrier layer covering the quantum well portions. The quantum box array is designed so that interaction energy between electrons or holes is amply larger than transfer energy between the quantum boxes. A control electrode is provided on the second barrier layer to vary the number of electrons or holes in the quantum box array by changing the potential of the control electrode. In spite of using a relatively small number of electrons or holes, the quantum device can suppress fluctuation in density of electrons or holes, can have three or more states, and reduces the power consumption.

Abstract: An electromagnetic wave detector formed of semiconductor materials includes at least one quantum well in which there is provided a fine layer of a material with a gap width that is smaller than that of the quantum well layer. For example, in the case of a GaAlAs/GaAs/GaAlAs, there is provision for a fine layer of InAs. In this way, the difference of energy levels between the two permitted levels is increased and detection of short wavelengths may be accomplished.

Abstract: A solar cell formed from a semiconductor having a relative wide band-gap E.sub.b- characterized by a multi-quantum well system incorporated in the depletion region of the cell in which the quantum wells comprise regions of semiconductor with a smaller band gap separated by small amounts of the wider band-gap semiconductor (E.sub.b) so that the effective band-gap for absorption (E.sub.a) is less than E.sub.b.

Abstract: The present invention relates to novel optical devices operating in the infrared, based on indirect narrow-gap superlattices (INGS) as the active optical materials. The novel optical devices include (1) wideband all-optical switches, which combine small insertion loss at low light intensities with efficient optical switching and optical limiting at high intensities, and (2) wideband infrared detectors with high collection efficiency and low tunneling noise currents, suitable for use in longwave infrared focal plane arrays. INGS comprise multiple semimetal/semiconductor layers having compatible crystal symmetry across each heterojunction between a given semimetal and the adjoining semiconductor, wherein each semimetal layer sandwiched between semiconductor layers is grown thin enough that each semimetal layer becomes a semiconductor, and wherein each semiconductor layer is thin enough that there is coupling between adjacent semiconductor layers.

Abstract: A semiconductor infrared detector having a transistor structure with a superlattice base. The superlattice base is between a multiple quantum well (MQW) structure and an electron energy high pass filter. The superlattice base restricts electrons to minibands resulting in no overlap in energy between the energies of the photoelectrons and the dark electrons. As a result, more photoelectrons reach the collector, and the emitter to collector photocurrent transfer ratio is increased. The increased transfer ratio results in increased sensitivity of the detector. The superlattice base between the MQW structure and the electron energy high pass filter comprises multiple alternating wells and barriers. The wells are preferably made of GaAs and the barriers are preferably made of Al.sub.x Ga.sub.1-x As, where x is equal to 0.25.

Abstract: A semiconductor laser capable of emitting blue or green light is disclosed. The semiconductor laser comprises an n-type ZnMgSSe cladding layer, an active layer, a p-type ZnMgSSe cladding layer, a p-type ZnSe contact layer and a p-type ZnTe contact layer which are stacked in this sequence on an n-type GaAs substrate. A p-side electrode is provided on the p-type ZnTe contact layer. An n-side electrode is provided on the back surface of the n-type GaAs substrate. A multiquantum well layer comprising quantum wells made of p-type ZnTe and barriers made of p-type ZnSe is provided in the depletion layer produced in the p-type ZnSe contact layer along the junction interface between the p-type ZnSe contact layer and the p-type ZnTe contact layer. Holes injected from the p-side electrode pass through the junction by the resonant tunneling effect through quantum levels formed in the quantum wells of the multiquantum well layer.

Abstract: Multiple quantum wells within an impact avalanche transit time device (IMPATT) utilizing a plurality of gallium arsenide/aluminum gallium arsenide heterojunctions are used to provide a high power, high frequency, high efficiency device operating at 50 GHz and up. The multiple quantum wells defined by the heterojunctions between pairs of gallium arsenide quantum wells and aluminum gallium arsenide barrier layers improves the nonlinearity of the avalanche process within the gallium arsenide quantum wells and reduces the ionization rate saturation limitations. Optical injection locking of the current through the IMPATT device is achieved by irradiating the active layer of the IMPATT device with modulated laser light.

Abstract: An electrically programmable antifuse element using ferroelectric materials for the insulative dielectric layer, methods for producing same, and an integrated circuit applying a plurality of ferroelectric antifuse elements in a two dimensional matrix of rows and columns for use as a programmable logic device (PLD) or as a programmable read-only memory (PROM). A ferroelectric material is formed between two conductive electrodes to create a ferroelectric antifuse element. In an alternative embodiment, a plurality of chemically distinct materials is layered to form the dielectric layer. The combined application of an AC electric field and a DC electric field breaks down the ferroelectric material to form a low-resistance conductive filament. The synergy of the two electric fields permits programming antifuse elements of the present invention by applying DC electric fields as low as 2 volts amplitude.

Abstract: An optical switch includes a semiconductor substrate having a surface, a ridge waveguide disposed on the surface of the semiconductor substrate and including an optical waveguide layer having an MQW structure, first and second cladding layers sandwiching the optical waveguide layer, and a switch disposed in a part of the ridge waveguide. A part of the MQW optical waveguide layer included in the switch is thicker than the other part of the optical waveguide layer, whereby the energy band gap of the optical waveguide layer of the switch is smaller than the energy band gap of the other part of the optical waveguide layer and larger than the energy of the signal light. Therefore, the absorption loss of the signal light traveling through the optical waveguide layer is reduced. Furthermore, since the variation in the refractive index of the switch when current is applied to the switch is increased, the ON/OFF ratio of the switch is increased.

Abstract: A Hall effect sensor of two-dimensional electron gas type comprising, on an insulating substrate, a quantum well structure, a carrier injection layer adjacent to the quantum well structure, of thickness less than 250 .ANG. and having an density per unit area of donors integrated over the whole thickness of the carrier injection layer less than 5.times.10.sup.12 cm.sup.-2, an insulating burial layer deposited on the carrier injection layer, having a conduction band with an energy level greater than the Fermi energy of the sensor and a thickness greater than 200 .ANG.. Applicable to the field of electricity meters and current sensors.

Abstract: A multi-layer superlattice quantum well thermoelectric material using materials for the layers having the same crystalline structure. A preferred embodiment is a superlattice of Si and SiGe, both of which have a cubic structure. Another preferred embodiment is a superlattice of B-C alloys, the layers of which would be different stoichometric forms of B-C but in all cases the crystalline structure would be alpha rhombohedral.

Abstract: On a substrate having a surface slightly tilted by an angle .alpha. within the range of from 0.5 to 10 degrees from the (110) plane in the <00-1> direction, a superlattice structure having a periodicity in both <110> and <001> directions is formed. Various band structures are possible by selecting an appropriate constituent material and periodicity for the superlattice structure. When current flows in a direction without periodicity, a very high mobility is obtained as a result of suppressed alloy scattering. If current is caused to flow in a direction with periodicity, and the periodicity is properly selected, optical phonon scattering can also be suppressed.

Abstract: The invention is a resonant tunnel effect quantum well transistor. To improve the gain by avoiding the storage of charges in the well, which consists of layer (14) with a narrow forbidden band and two barriers (13, 15) with a wide forbidden band, the quantum well is laterally bounded--in the plane of the layers--by a depleted region (22) which forms a quantum box whose dimensions are smaller than the De Broglie wavelength. Application to fast electronics (200 GHz).

Abstract: A data processing system formed of a collective element of quantum boxes including an electrode and a plurality of quantum boxes which respectively have a barrier layer made of the first semiconductor on the electrode and a well layer made of a second semiconductor adjacent to the barrier layer. The first semiconductor has an electron affinity .PHI..sub.B and an energy gap E.sub.gB. The second semiconductor has an electron affinity .phi..sub.W and an energy gap E.sub.gW. The equations .phi..sub.W >.phi..sub.B and .phi..sub.W +E.sub.gW >.phi..sub.B +E.sub.gB are simultaneously satisfied.

Abstract: A superconducting thin film formed on a substrate, comprising at least one oxide superconductor layer formed on the principal surface of said substrate and at least one oxide layer formed of an oxide which compensates for crystalline incompleteness at the surface of said oxide superconductor layer, and which is arranged on or under the superconducting layer.

Abstract: A field effect semiconductor device having multiple vertically stacked channels (12, 14, 16) separated by barrier layers comprising wide bandgap material (18) is provided. The channels (12, 14, 16) are formed on a wide bandgap buffer layer (11) and each channel is coupled a N-type drain region (22b). Each channel is also coupled to an N-type source region (25b). With appropriate gate bias on a gate electrode (17), quantized energy levels in the channels (12, 14, 16) are aligned to provide self-doping by electrons in the valence band of the P-channel (14) moving to the conduction band of the N-channels (12, 16) providing peak channel conductivity. At higher gate bias, one of the N-channels (12) becomes non-conductive creating a negative resistance region.

Abstract: A field effect semiconductor device having multiple vertically stacked channels (12, 14, 16) separated by barrier layers comprising wide bandgap material (18) is provided. The channels (12, 14, 16) are formed on a wide bandgap buffer layer (11) and each channel is coupled a P-type drain region (22b). Each channel is also coupled to an N-type source region (25b). With appropriate gate bias on a gate electrode (17), quantized energy levels in the channels (12, 14, 16) are aligned providing peak current flow by electrons tunneling from the conduction band of one or more N-channels (12, 16) to the valence band of the P-channel (14).

Abstract: An electrical junction is precisely located between a highly p doped semiconductor material and a more lightly n doped semiconductor material by providing a lightly p doped buffer region between the two materials, with a doping level on the order of the n doped material's. The buffer region is made wide enough to establish an electrical junction at approximately its interface with the n doped material, despite a diffusion of dopant from the p doped material. When applied to a heterojunction bipolar transistor (HBT), the transistor's base serves as the heavily p doped material and its emitter as the more lightly n doped material. The buffer region is preferably employed in conjunction with a graded superlattice, located between the buffer and emitter, which inhibits dopant diffusion from the base into the emitter.

Abstract: A single-crystal, multi-layer device incorporating an IR absorbing layer that is compositionally different from the Ga.sub.x Al.sub.1-x Sb layer which acts as the electron emitter. Many different IR absorbing layers can be envisioned for use in this embodiment, limited only by the ability to grow quality material on a chosen substrate. A non-exclusive list of possible IR absorbing layers would include GaSb, InAs and InAs/Ga.sub.w In.sub.y Al.sub.1-y-w Sb superlattices. The absorption of the IR photon excites an electron into the conduction band of the IR absorber. An externally applied electric field then transports electrons from the conduction band of the absorber into the conduction band of the Ga.sub.x Al.sub.1-x Sb, from which they are ejected into vacuum. Because the band alignments of Ga.sub.x Al.sub.1-x Sb can be made the same as that of GaAs, emitting efficiencies comparable to GaAs photocathodes are obtainable.

Abstract: A method for using atomic layer epitaxy (ALE) and/or migration enhanced epitaxy (MEE) to grow high efficiency quantum wells in II-VI laser diodes. The substrate and previously grown layers of the laser diode are heated to a temperature less than or equal to about 200.degree. C. in an MBE chamber. Sources of Cd, Zn, and Se are injected alternately into the chamber to grow a short-period strained-layer superlattice (SPSLS) quantum well layer including overlaying monolayers of Cd, Zn and Se. The quantum well layer is described by the notation [(CdSe).sub.m (ZnSe).sub.n ].sub.p where m, n and p are integers.

Abstract: A magneto-optical recording medium comprises a base film having a certain crystal plane oriented in parallel to a substrate and a recording film formed on the base film. The recording film is composed of plural pairs of Mn alloy group magnetic thin film layer having a C-axis-oriented crystalline magnetic anisotropy and a nonmagnetic thin film layer having an interatomic spacing approximate to that of the base film, alternately laminated each other, so that the Mn alloy group magnetic film having a C-axis-oriented crystalline magnetic anisotropy is epitaxially grown on the substrate at a low temperature through the base film with high thermal stability and great magneto-optical effect.

Abstract: A resonant-tunneling heterojunction bipolar transistor (RHBT) device having a superlattice structure and a PN junction. The RHBT includes an emitter layer; a base layer; a collector layer operatively facing the base layer to form a PN junction at the face between the base layer and the collector layer; and a superlattice structure including at least one quantum well defining a sub-band of energy at which carriers resonant-tunnel therethrough, formed at least in the emitter layer and operatively facing to the base layer.The RHBT has a differential negative resistance characteristics for realizing a variety of logic circuits and includes an electron resonance and a positive hole resonance, for which the generation condition is changeable in response to a mole fraction of material of the emitter layer.

Abstract: A solid state, electronic, optical transition device includes a multiple-layer structure of semiconductor material which supports substantially ballistic electron/hole transport at energies above/below the conduction/valance band edge. The multiple layer structure of semiconductor material includes a Fabry-Perot filter element for admitting electrons/holes at a first quasibound energy level above/below the conduction/valance band edge, and for depleting electrons/holes at a second quasibound energy level which is lower/higher than the first energy level. Such an arrangement allows common semiconductor material to be used to produce emitters and detectors and other devices which can operate at any of selected frequencies over a wide range of frequencies.

Abstract: An opto-electronic device with the physical and chemical characteristics at the junction thereof being well matched is disclosed. The opto-etectronic device includes a wafer, a first layer grown on the wafer, and a second layer grown on the first layer, wherein one of the first and second layers is an ordered structure while the other is a disordered structure.

Abstract: A gain-stable npn heterojunction bipolar transistor includes a graded superlattice between its base and emitter consisting of multiple discrete periods, with each period having a layer of base material and another layer of emitter material. The thicknesses of the base material layers decrease while the thicknesses of the emitter material layers increase in discrete steps for each successive period from the base to the emitter. The thickness of each period is preferably at least about 20 Angstroms, with the superlattice including more than five periods. The superlattice is preferably doped to establish an electrical base-emitter junction at a desired location. The graded superlattice inhibits the diffusion of beryllium p dopant from the base into the emitter during transistor operation, thus stabilizing the device's gain and turn-on voltage.

Abstract: This invention provides a blue light semiconductor optical device capable of effectively oscillating in a temperature range above room temperature. A double hetero structure semiconductor optical device according to the invention is made of a compound semiconductor containing Zn and/or Cd as group II elements and S and/or Se and/or Te as group VI elements and comprises an active layer, a light confining layer and a cladding layer arranged on a semiconductor substrate as well as a multiquantum barrier structure having a strained superlattice layer in part of the cladding layer or the light confining layer for an effect of reflecting incident carriers as waves in phase conditions capable of allowing mutual enhancement of the incident and reflected waves.

Abstract: One or more double barrier resonant tunneling filters are provided for electron propagation mode control in nanostructure quantum wire electron waveguides and in quantum interference devices in the waveguide.

Abstract: An avalanche photodiode includes a multiplication layer and a photoabsorption layer, and the multiplication layer is formed of a semiconductor superlattice structure composed of a number of well layers each of which is formed of a short period superlattice of at least two kinds of semiconductors and which can be equivalently regarded to be a mixed crystal of the at least two kinds of semiconductors. In the short period superlattice, the mini-bands are formed within the superlattice well layers having its effective forbidden band width, which is larger than the forbidden band width in a bulk condition of a semiconductor layer constituting a well in the short period superlattice. Thus, the dark current due to the inter-band tunnel transition within the same well layer is decreased. Therefore, a low noise characteristics and a low noise and high response speed characteristics obtained by a high ionization rate ration can be simultaneously realized.

Abstract: A single quantum well II-VI laser diode without semiconductor cladding layers includes a pn junction formed by overlaying light-guiding layers of p-type and n-type ZnSe on an n-type GaAs substrate. A CdSe/ZnSe short-period strained-layer superlattice single quantum well active layer is positioned between the guiding layers. An Au electrode overlays the p-type guiding layer opposite the single quantum well active layer. The guiding layers have thicknesses which enable the substrate and Au electrode to confine the light beam generated by the device within the active layer and the guiding layers.

Abstract: A thin film EL element capable of emitting light of different colors desired even at a low applied voltage owing to its high luminescent efficiency and freedom from crystal defects. The thin film EL element is of the dual dielectric structure having a transparent substrate (1), and a transparent conducting film (2), a first dielectric layer (3), a luminescent layer (4), and a second dielectric layer (5), which are formed on top of the other on the substrate, the transparent conducting film and the second dielectric layer being provided with respective electrodes (6a, 6b). It is characterized in that the luminescent layer has a superlattice structure represented by (luminscent host material)/(luminescent host material):(luminescent center impurity). The luminescent layer permits the doping of various luminscent center impurities while keeping its electrical neutrality without a need for the addition of charge compensating elements.

Abstract: A semiconductor device with a strained-layer superlattice is disclosed, in which a first semiconductor and a second semiconductor of a lattice constant smaller than that of the first semiconductor are stacked on a clad layer of a lattice constant substantially intermediate between those of the first and second semiconductors to form the strained-layer superlattice. The lattice constant of the strained-layer superlattice in the direction of its plane in the free space is nearly equal to the lattice constant of the clad layer. A third semiconductor of a lattice constant substantially equal to that of the clad layer is laminated between the first and second semiconductors stacked one on the other.

Abstract: An article that comprises novel means for modulating the transparency of a semiconductor body in accordance with a modulating signal is disclosed. The body comprises one or more quantum wells (QWs), and the modulation mechanism comprises changing the free carrier distribution function in the QWs. An important feature of the inventive article is the use of (relatively long wavelength) inter-subband radiation (ISBR) to change the transparency of the body for (relatively short wavelength) inter-band radiation (IBR). In preferred embodiments the modulating signal is an electric field applied across the QWs, such that ISBR absorption can be tuned by means of the Stark effect. One embodiment of the invention makes it possible to rapidly modulate IBR, and another embodiment can form narrow (typically less than 10 ps) IBR pulses.

Abstract: A method of fabricating a semiconductor heterostructure includes the growth of a quantum well active region that is highly lattice-mismatched relative to a substrate. A buffer layer having a thickness above a critical value is grown on the substrate whereby the stress due to a lattice constant mismatch between the buffer layer and substrate is relieved through the formation of misfit dislocations. A strained superlattice structure is grown on the buffer layer in order to terminate any upwardly-propagating dislocations. An unstrained barrier layer is subsequently grown on the superlattice structure. The fabrication method concludes with the growth of a quantum well structure on the unstrained layer wherein a lattice constant mismatch between the quantum well structure and the unstrained barrier layer is smaller than the lattice constant mismatch between the quantum well structure and the substrate.

Abstract: A multiple quantum well (MQW) radiation sensor distinguishes radiation within a desired bandwidth, particularly long wavelength infrared radiation (LWIR), from background high intensity noise radiation that excites majority-minority charge carrier pairs. A minority charge carrier collector is provided at one end of the MQW, and the flow of minority charge carriers to the collector is sensed. The minority charge carrier flow provides an indication of the majority charge carrier flow that is attributable to the noise radiation rather than to radiation within the desired bandwidth, and can thus be used to provide a corrected indication of the desired bandwidth radiation.

Abstract: A field-effect transistor comprising a semiconductor substrate having source and drain regions and a gate electrode, wherein a thin organic film including donor and acceptor molecules is provided between the semiconductor substrate and the gate electrode. When a predetermined voltage is applied to the gate electrode, charge transfer occurs between the donor and acceptor molecules included in the thin organic film, thereby controlling the surface potential of the semiconductor substrate.

Abstract: A semiconductor luminous element has cladding layers on both sides of its active layer; and it has a multi-quantum barrier layer which is in contact with the active layer on at least a portion of at least one of the cladding layers. This multi-quantum barrier layer is formed of an alternating stack of superlattice barrier layers and superlattice well layers. The energy gap of the well layers is smaller than that of the active layer, and the quantized energy gap of the multi-quantum barrier layer is larger than the energy gap of the active layer. A superlattice structure for semiconductor devices, which confines electrons and holes, is formed out of the active layer and a cladding layer provided on at least one side of that active layer. A multi-quantum barrier layer is in contact with the active layer on at least a portion of the cladding layer. This multi-quantum barrier layer is formed of an alternating stack of superlattice barrier layers and superlattice well layers.

Abstract: A planar frequency tripler comprised of two semiconductor diode structures connected back-to-back by an n.sup.+ doped layer (N.sup.+) of semiconductor material utilizes an n doped semiconductor material for a drift region (N) over the back contact layer in order to overcome a space charge limitation in the drift region. A barrier layer (B) is grown over the drift region, after a sheet of n-type doping (N.sub.sheet) which forms a positive charge over the drift region, N, to internally bias the diode structure. Two metal contacts are deposited over the barrier layer, B, with a gap between them. To increase the power output of the diodes of a given size, stacked diodes may be provided by alternating barrier layers and drift region layers, starting with a barrier layer and providing a positive charge sheet at the interface of a barrier on both sides of each drift region layer with n-type .delta. doping. The stacked diodes may be isolated by etching or ion implantation to the back contact layer N.sup.

Abstract: A semiconductor laser device includes a first conductivity type cladding layer, an active layer, and a second conductivity type cladding layer disposed on a first conductivity type substrate. A multiquantum barrier structure is disposed between the active layer and one of the cladding layers. The active layer includes a layer with a lattice constant different from the lattice constant of the first conductivity type substrate by at least 0.1 percent so that a strain is applied to the active layer. The threshold current is significantly reduced, resulting in a high power semiconductor laser capable of operating at a high temperature.

Abstract: This invention embodies p-n junction devices comprising Group III-V compound semiconductors in which the p or n or both p and n regions are formed by a superlattice selectively doped with an amphoteric Group IV element dopant selected from carbon, germanium and silicone. The superlattice includes a plurality of periods, each including two layers. Depending on the conductivity type, only one of the layers in the periods forming the superlattice region of said type of conductivity is selectively doped with said dopant, leaving the other layer in these periods undoped. The superlattice is formed by Molecular Beam Epitaxy technique, and the dopant is incorporated into respective layers by delta-doping as in a sheet centrally deposited between monolayers forming the respective layers of the period. Each period includes 5 to 15 monolayers deposited in the two layers in a numerical ratio corresponding to a cation compositional ratio in the compound semiconductor. Low growth temperatures, e.g. ranging from 410.

Abstract: A method of selectively tuning the bandedge of a semi-conductor heterostructure includes forming a disordered region which is spatially separated from a quantum well active region, and subsequently annealing the heterostructure so that vacancies/defects in the disordered region diffuse into the quantum well region and enhance interdiffusion at the well-barrier heterojunctions. The tuning is spatially selective when the heterostructure is masked so that exposed portions correspond to regions where bandgap tuning is desirable. The heterostructures of interest are III-V material systems, such as AlGaAs/GaAs, where the active region includes structures such as a single quantum well, a multiple quantum well, or a superlattice.

Abstract: An electroluminescent device of compound semiconductor including a semiconductor substrate, a buffer layer epitaxially grown on the semiconductor substrate and a luminescent layer epitaxially grown on the buffer layer, the substrate being formed from a single crystal of zinc sulfide, zinc selenide or a mixed crystal thereof, the luminescent layer being formed from aluminum nitride, indium nitride, gallium nitride or a mixed crystal of at least two of the nitrides.

Abstract: A ferromagnetic thin film of manganese and aluminum having varied atomic concentrations of manganese and aluminum in the direction perpendicular to the film plane, preferably the Mn atomic concentration being preferably in a range of 45 to 65% by atom, has a spontaneous magnetization equivalent to that of the bulk of manganese-aluminum alloy and also a high magnetic anisotropy.In addition, a magnetic recording medium comprises a substrate and a magnetic film formed on the substrate, the magnetic film being a thin film in a stacked structure of thin layers of manganese and thin layers of aluminum, laid open upon one another alternatingly in the film thickness direction.Finally, a manganese-silicon magnetic multi-layer film comprises thin layers of manganese and thin layers of silicon laid upon one another alternatingly.

Abstract: A non-linear optical device having the TBQ structure comprises an active layer forming a quantum well for interacting with an incident optical beam, an electron removal layer provided adjacent to the active layer at a first side thereof with a first barrier layer intervening therebetween for removing the electrons from the active layer; and a hole removal layer provided adjacent to the active layer at a second, opposite side of the active layer with a second barrier layer intervening therebetween for removing the holes from the active layer; wherein the first and second barrier layers have respective thicknesses determined such that the probability of tunneling of the electrons through the first barrier layer and the probability of tunneling of the holes through the second barrier layer are substantially equal with each other.