156 results about "Semiconductor heterostructures" patented technology

Monolithic lattice-mismatched semiconductor heterostructures are fabricated by bonding patterned substrates with alternative active-area materials formed thereon to a rigid dielectric platform and then removing the highly-defective interface areas along with the underlying substrates to produce alternative active-area regions disposed over the insulator and substantially exhausted of misfit and threading dislocations.

Monolithic lattice-mismatched semiconductor heterostructures are fabricated by bonding patterned substrates with alternative active-area materials formed thereon to a rigid dielectric platform and then removing the highly-defective interface areas along with the underlying substrates to produce alternative active-area regions disposed over the insulator and substantially exhausted of misfit and threading dislocations.

An improved light emitting heterostructure. In particular, a nitride-based light emitting heterostructure is provided that includes a light generating structure and a distributed semiconductor heterostructure Bragg reflector structure formed above the light generating structure. In operation, the light generating structure generates light, a portion of which is reflected by the distributed semiconductor heterostructure Bragg reflector structure, thereby increasing the total amount of light that can be emitted from the heterostructure.

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.

An X-ray detector (401, 501, 601) has a detecting element that comprises a semiconductor heterostructure where an undoped Germanium layer (402, 502) is enclosed between two oppositely doped Gallium Arsenide layers (403, 404, 503, 505).

An epitaxially grown semiconductor heterostructure has an inner region (5) which is substantially laterally confined by confinement regions (9) and has enhanced transverse confinement by enhanced transverse confinement layers (3, 7). The latter layers are not exposed outside the growth chamber during processing, by stopping the etching for producing the lateral confinement, above the lower enhanced transverse confinement layer (3) and growing such an upper layer (7) after making the lateral confinement regions (9). The structure is intended to be used in particular having the inner region act as an active laser region, for instance in InP-based 1.3 mu m wavelength lasers. Then the simultaneous lateral confinement, enhanced transverse confinement and exposure protection enables simultaneously a low threshold current, a small temperature sensitivity and reliable, long life operation. The enhanced transverse confinement layers (3, 7) could comprise aluminium protected from oxidation during processing. Such a laser will then be protected from a declined reliability.

The invention provides transistors and rectifiers utilizing hybrid electrodes and methods of fabricating the same. A heterostructure semiconductor transistor can include a III-N-type semiconductor heterostructure including a barrier layer overlying an active layer and a hybrid electrode region including a hybrid drain electrode region. Further, a heterostructure semiconductor rectifier can include a III-N-type semiconductor heterostructure and a hybrid electrode region including a hybrid cathode electrode region. Furthermore, the hybrid electrode region of the transistor and rectifier can include permanently trapped charge located under a Schottky contact of the hybrid electrode region.

The invention discloses a method to produce IV-VI semiconductor single-crystal thin film and the hetero-structure thereof. Under the condition of accurately controlled ultra-high vacuum, IV-VI atom and molecular beams vaporized from a beam source furnace encounter a clean single-crystal liner surface with good crystal surface orientation, and atom and molecular reaching the surface of the liner form high-quality single-crystal thin film after processes such as attachment, transition, and crystallization on the surface of liner. Through the accurate control of growth conditions, such as beam runoff and linear temperature, extended IV-VI compounds grow on the surface of linear by a molecular layer and a molecular layer. The method can grow IV-VI semiconductor hetero-structures, including quantum-well and super-lattice. The production cost is low, and the quality is high.

Planar Schottky diodes for which the semiconductor material includes a heterojunction which induces a 2DEG in at least one of the semiconductor layers. A metal anode contact is on top of the upper semiconductor layer and forms a Schottky contact with that layer. A metal cathode contact is connected to the 2DEG, forming an ohmic contact with the layer containing the 2DEG.

The invention relates to a method for forming a semiconductor heterostructure by providing a substrate with a first in-plane lattice parameter a₁, providing a buffer layer with a second in-plane lattice parameter a₂ and providing a top layer over the buffer layer. In order to improve the surface roughness of the semiconductor heterostructure, an additional layer is provided in between the buffer layer and the top layer, wherein the additional layer has a third in-plane lattice parameter a₃ which is in between the first and second lattice parameters.

A strained semiconductor heterostructure (10) comprises an injection region comprising a first emitter layer (11) having p-type conductivity and a second emitter layer (12) having n-type conductivity, and a light generation layer (13) positioned between the first emitter layer (11) and the second emitter layer (12). An electron capture region (14) is positioned between the light generation layer (13) and the second emitter layer (12), said electron capture region comprising a capture layer (16) adjacent to the second emitter layer, and a confining layer (15) adjacent to said electron capture layer. According to the present invention, the widths and materials of the confining and capture layers (15, 16) are selected to provide energy difference between one of localized energy levels for electrons in the capture layer (16) and the conduction band bottom of the second emitter layer (12) equal to the energy of the optical phonon.

A method of fabricating semiconductor heterostructures including the steps of: (a) positioning a silicon wafer in a suitable environment and (b) processing the silicon substrate by applying several processing steps. A first optional processing step includes growing a graded buffer layer on a silicon substrate by low-energy plasma-enhanced chemical vapor deposition (LEPECVD). A second processing step includes growing a constant composition buffer layer by LEPECVD. A third processing step includes subjecting the surface of the strain-relaxed buffer layer to a deposition process for a period of time and under prescribed conditions, in order to grow at least one additional layer. Subsequently, devices may be processed from the grown layer stack by using a prescribed sequence of steps including non-standard CMOS processes.

The invention belongs to the technical field of semiconductor photocatalysis, and particularly relates to a WS2/ZnIn2S4 composite visible light catalyst and a preparation method thereof. The inventionprovides a WS2/ZnIn2S4 composite visible light catalyst and a preparation method thereof. The preparation method is characterized in that a WS2 nano sheet used as a promoter is tightly combined withZnIn2S4 particles through a hydrothermal reaction, thereby forming the WS2/ZnIn2S4 composite visible light catalyst. Compared with a pure ZnIn2S4 photocatalyst, the prepared WS2/ZnIn2S4 composite visible light catalyst can effectively promote separation of photogenerated charges and reduce combination of photogenerated electrons and holes due to the formation of a semiconductor heterostructure, sothat the photocatalytic hydrogen production performance can be greatly improved. The WS2/ZnIn2S4 composite visible light catalyst and the preparation method thereof which are provided by the invention provide a new idea and a new way for design and development of a novel efficient visible light catalyst.

The present invention provides quantum cascade lasers and amplifier that operate in a frequency range of about 1 Terahertz to about 10 Terahertz. In one aspect, a quantum cascade laser of the invention includes a semiconductor heterostructure that provides a plurality of lasing modules connected in series. Each lasing module includes a plurality of quantum well structure that collectively generate at least an upper lasing state, a lower lasing state, and a relaxation state such that the upper and the lower lasing states are separated by an energy corresponding to an optical frequency in a range of about 1 to about 10 Terahertz. The lower lasing state is selectively depopulated via resonant LO-phonon scattering of electrons into the relaxation state.

A low power, side-emitting semiconductor laser diode is provided. The laser diode is formed from a semiconductor heterostructure having an active layer sandwiched between an n-type layer and a p-type layer, wherein the active layer forms a gain medium of width W. Front and back reflectors of reflectivity Rf and Rb are arranged on opposing side facets of the semiconductor heterostructure part to form a cavity of length L containing at least a part of the active layer which thus forms the gain medium for the laser diode, the gain medium having an internal loss αi. To achieve stable, low power operation close to threshold, the laser diode is configured with the following parameter combination: width W: 1 μm≦W≦2 μm; cavity length L: 100 μm≦L≦600 μm; internal loss αi: 0 cm⁻¹αi≦30 cm⁻¹; back reflectivity Rb: 100≧Rb≧80%; and front reflectivity Rf: 100≧Rf≧60%.

The invention discloses a heterostructure photoanode for a dye-sensitized solar cell, comprising conductive glass and a dye absorption layer coated on the conductive glass. The dye absorption layer is a TiO2-semiconductor heterostructure film, wherein a primary structure is TiO2 nano-fiber or/and TiO2 nano-tubes, and a secondary structure is at least one of semiconductor nano-particles, semiconductor nao-rods and semiconductor nano-wires constructed by semiconductor nano-fiber or/and semiconductor nano-tubes, namely that 1-D heterostructure nano-material as the dye absorption layer of the photoanode of a dye-sensitized solar cell. The combination of the structural characteristics of 1-D nano-size and the polarization property of galvanic couple formed by TiO2/semiconductor composite system interface can enhance the transmission and the separation of electric charges and improve the electronic transmission efficiency; meanwhile, a huge specific surface area can effectively improve the amount of dye absorption and the light utilization efficiency and further improve the photoelectric transformation efficiency of the dye-sensitized solar cell by 10 percent.

A non-lasing superluminescent light emitting diode (SLED) comprises a semiconductor heterostructure forming a PN junction and a waveguide defining an optical beam path. The heterostructure includes a gain region and an absorber region in series with the gain region in the optical beam path. A voltage is applied to the PN junction in the gain region by first contact means, so that light emission from the active region and along the optical beam path is produced. According to the invention, second contact means are provided, contacting the PN junction in the absorber region and operable to remove charge carriers generated by absorption in the absorber region. The second contact means are not connected to a voltage source, but to a charge carrier reservoir such as a metal surface. According to a preferred embodiment, the two end facets of the waveguide are perpendicular to the optical beam path.

In order to achieve lateral current spreading between a current injecting or current collecting surface of an electrode and an active surface of an active region in a semiconductor device such as a light emitting diode, a layered semiconductor heterostructure is arranged between the electrode and the active surface. The heterostructure includes at least two semiconductor layers forming a heterojunction therebetween, whereby the semiconductor layers are composed of different semiconductor materials or different compositional proportions of the same compound semiconductor. An enrichment region for the majority charge carriers is formed in one of the layers adjacent the heterojunction, and a majority charge carrier energy band discontinuity exists at the heterojunction. Each enrichment region provides a strong lateral current spreading effect, such that a stacked arrangement of plural heterojunction layer pairs brings about a strong step-wise lateral current spreading. The light output and efficiency of a light emitting diode is substantially improved by incorporating such a current spreading heterostructure.