215 results about "Electron concentration" patented technology

Alternate layers of wide band gap and narrow band gaps of different kinds of semiconductors are used to form multiple channels of a FET. The channels are doped or formed as 2-DEG/2-DHG in narrow band semiconductor by charge supply layer in the wide band gap semiconductor. The different kinds of semiconductors form heterojunctions to confine the electrons/holes in separate thin spikes layers. A number of spikes (3-10 nm thick) of different doped or 2-DEG/2-DHG concentrations in various channels can result in overall electron concentration gradient such as a 1/x³ electron/hole concentrations profile. Such an electron/hole concentration gradient can result in a linear variation of drain current with voltage to obtain a wide dynamic range.

The invention provides a silicon controlled rectifier (SCR)-based electrostatic protection device of an integrated circuit, which can improve the maintaining voltage, wherein an electrostatic discharge protection structure of a high-voltage device improves the structure of a traditional high-voltage protection device, an N injection region is increased below the anode end of the original SCR, and the electron concentration at the lower part of an anode of the SCR is improved. By adopting the device, the problem of low maintaining voltage of the traditional electrostatic protection device of the integrated circuit can be solved; by adjusting the injection dose, the ESD (electrostatic discharge) voltage of the original device can be reduced, and the maintaining voltage can be improved; furthermore, the electrostatic discharge protection capability and the capability of resisting the latch-up effect of the integrated circuit can be upgraded.

An InxGa1-xAsySb1-y (0<x<=1, 0<=y<=1) thin film of an electron concentration of 2x1016/cm3 or more is formed on a dielectric substrate. Temperature dependence of resistance is controlled by composition setting or donor atom doping of the thin film to reduce the temperature dependence. As a result, a magnetic sensor of small temperature dependence of device resistance and high sensitivity can be provided.

Gallium nitride material devices and methods associated with the same. In some embodiments, the devices may be transistors which include a conductive structure connected to a source electrode. The conductive structure may form a source field plate which can be formed over a dielectric material and can extend in the direction of the gate electrode of the transistor. The source field plate may reduce the electrical field (e.g., peak electrical field and/or integrated electrical field) in the region of the device between the gate electrode and the drain electrode which can lead to a number of advantages including reduced gate-drain feedback capacitance, reduced surface electron concentration, increased breakdown voltage, and improved device reliability. These advantages enable the gallium nitride material transistors to operate at high drain efficiencies and/or high output powers. The devices can be used in RF power applications, amongst others.

Provided is a nitride semiconductor light emitting device having enhanced output power and resistance to electrostatic discharge. The light emitting device comprises an n-side contact layer formed on a substrate, a current diffusion layer formed on the n-side contact layer, an active layer formed on the current diffusion layer, and a p-type clad layer formed on the active layer. The current diffusion layer is formed by alternately stacking at least one first InAlGaN layer having a higher electron concentration than that of the n-side contact layer and at least one second InAlGaN layer having a lower electron concentration than that of the n-side contact layer.

The invention discloses a THz-wave detector, which uses a high-electron-mobility field effect transistor (FET) with higher two-dimensional electron concentration as a basic structure unit, wherein the FET is provided with a source electrode, a gate electrode and a drain electrode. The THz-wave detector is characterized in that the device structure of the THz-wave detector comprises three lead electrodes, three low pass filters and a group of THz-wave coupled antennas, wherein the three electrodes of the FET and the THz-wave coupled antennas are connected to jointly serve as antennas; and the three electrodes of the FET are respectively connected with the corresponding lead electrodes through the low pass filters. The THz-wave detector has the advantages that the antennas are separated from the lead electrodes through the low pass filters, so the resonance performance of the antennas can be guaranteed, and the decrease of the device responsivity, which is caused by the leakage of high frequency THz-wave signals produced by the antennas to the lead electrodes through straight conducting wires, is prevented; and an ohmic contact is simultaneously provided with the source electrode, the drain electrode and the antennas, so the device structure is compact, the integration is facilitated, and a foundation is laid for the realization of the arraying and large-scale application of the THz-wave detector.

The invention discloses a flexible graphene composite film and a preparation method thereof. The preparation method comprises the following steps of: based on oxidized or reduced graphene and organic polymer or micromolecule with a special functional group as raw materials, forming a uniform composite material by utilizing the interaction of a surface functional group of graphene and an organic molecule group, and preparing the graphene composite film on the surfaces of different substrates through methods of spin coating, spraying and the like. According to the preparation method disclosed by the invention, by utilizing an electron withdrawing group, an electron-donating group or a conjugate group in the organic polymer or micromolecule, the hole or electron concentration on the surface of a graphene electrode is increased, the work function of the electrode is controlled, the conductivity of the graphene electrode is improved, and the application range of a device is widened. According to the flexible graphene composite film disclosed by the invention, because the interaction among the groups is utilized, the compatibility of the prepared composite film is better, the structure is uniform, and the flexible graphene composite film is suitable for the photoelectric field of solar batteries, sensors, organic light-emitting diodes, touch screens and the like.

In the case of a thick light-absorbing layer 2, a phenomenon of a decrease in the time resolution occurs. However, when the thickness of the light-absorbing layer 2 is limited, a portion of low electron concentration in one electron group is cut out, and hence overlap regions of adjacent electron concentration distributions decrease. Therefore, by shortening the transit time necessary for the passage of electrons, regions of overlapping electron distributions due to diffusion can also be suppressed. Furthermore, the strength of an electric field within a light-absorbing layer can be increased by thinning the light-absorbing layer. Therefore, the time resolution of infrared rays can be remarkably improved by a synergistic action of these effects. If it is assumed that the time resolution is 40 ps (picoseconds), for example, when the thickness of a light-absorbing layer is 1.3 μm which is nearly equal to the wavelength of infrared, then a possible time resolution is 7.5 ps when this thickness is 0.19 μm.

The invention discloses a carrier stored groove bipolar transistor, belonging to the technical field of semiconductor power apparatus. Based on traditional CSTBT (Carrier Stored Trench Bipolar Transistor), the carrier stored groove bipolar transistor provided by the invention uses a thin N+ layer structure 21 on the tail end of a P-base area 6 groove to replace a small sacrificial P-base area, thereby further improving electron concentration of a carrier storage layer and a drift region; withstand voltage and turn-off characteristic of the apparatus cannot be affected when conducting voltage drop of IGBT (Insulated Gate Bipolar Transistor) is effectively reduced, thereby preferably improving a compromising relationship of conduction loss and turn-off loss.

The invention discloses a p-i-n type InGaN solar cell possessing a superlattice structure. The current p-i-n type InGaN solar cell possesses a problem of low conversion efficiency. The p-i-n type InGaN solar cell provided in the invention can solve the above problem. The solar cell comprises, from bottom to top: a substrate; an AlN nucleating layer (11), which is growth at a high temperature; an unintended doped GaN buffer layer (12); an n-GaN layer (13) possessing a thickness of 50-100nm and an electron concentration of 1x1018-6x1019/cm<3>; a InGaN/GaN superlattice structure (14) possessing a period of 8-30; a p-GaN layer (15) possessing the thickness of 50-100nm and a hole concentration of 1x1017-6x1018/ cm<3>. The thickness of a trap layer InGaN (18) of the InGaN/GaN superlattice is 8-16nm. In ingredients are 15%-90%. The thickness of a barrier layer GaN (19) is 3-8nm. The concentration of carriers is 1x1016-2x1017/ cm<3>. Grid-shaped Ni/Au ohmic electrodes (16) are distributed on the surface of a P-GaN layer (15). An Al/Au ohmic electrode (17) is led out from a right side of the surface of the n-GaN layer (13). By using the solar cell of the invention, a short circuit current of the cell can be raised. The solar cell possesses high conversion efficiency and can be used for solar photovoltaic power generation.

A device comprising a two-dimensional electron gas that includes an active region located in a portion of the electron gas is disclosed. The active region comprises an electron concentration less than an electron concentration of a set of non-active regions of the electron gas. The device includes a controlling terminal located on a first side of the active region. The device can comprise, for example, a field effect transistor (FET) in which the gate is located and used to control the carrier injection into the active region and define the boundary condition for the electric field distribution within the active region. The device can be used to generate, amplify, filter, and/or detect electromagnetic radiation of radio frequency (RF) and/or terahertz (THz) frequencies.

The invention discloses a double-shell titanium dioxide catalyst with high photocatalytic hydrogen generation performance and a preparation method thereof, and relates to the field of semiconductor photocatalytic degradation water hydrogen generation materials, in particular to a semiconductor catalyst and a preparation method thereof. The catalyst aims at solving the problems that existing black titanium dioxide is low in photocatalytic activity and low in hydrogen generation amount when used as a photocatalyst for hydrogen generation. The catalyst is sequentially composed of a titanium dioxide crystal core, a reduction non-crystal layer and an oxidation crystal shell from inside to outside. The preparation method includes the steps of firstly, grinding and mixing, secondly, annealing; thirdly, washing to obtain black titanium dioxide powder; fourthly, oxidizing to obtain the double-shell titanium dioxide catalyst with high photocatalytic hydrogen generation performance. The catalyst has the advantages that the service life of electrons and electron holes is prolonged, the electron concentration is increased, and the hydrogen generation amount is remarkably increased when the catalyst is used as a photocatalyst for hydrogen generation. The preparation method is mainly used for preparing the double-shell titanium dioxide catalyst.

The invention discloses an electric propulsion plume test evaluation method, which comprises the following steps: measuring ion beam density, electron concentration and space plasma potential of a main beam plume region and a backflow plume region to obtain a force effect of plume on a satellite solar wing and a thermal radiation effect evaluation result; measuring charging voltage and leakage current of different materials on the surface of a solar cell array in a plume plasma environment and surface potential of the solar cell array in the plume plasma environment to obtain charging and discharging effect evaluation results of the plume for the surfaces of the satellite solar wing and a satellite body; and measuring plasma plume pollution amount of sensitive equipment test samples on thesurfaces of the satellite solar wing and the satellite body to obtain a sediment pollution effect evaluation result of the plume for the sensitive equipment on the surfaces of the satellite solar wing and the satellite body. The method realizes test analysis and research of plume's pollution to satellite surface, ion sputtering corrosion and the impact of plume on satellite surface potential.

A barrier layer made of Al_xGa_1-xN (0<x≦0.18) is formed in a light-emitting semiconductor device using gallium nitride compound having a multi quantum-well (MQW) structure. By controlling a composition ratio x of aluminum (Al) or thickness of the barrier layer, luminous intensity of the device is improved.

An n-cladding layer made of Al_xGa_1-xN (0<x≦0.06) is formed in a light-emitting semiconductor device using gallium nitride compound. By controlling a composition ratio x of aluminum or thickness of the n-cladding layer, luminous intensity of the device is improved.

A p-type layer and an n-type layer are formed in a light-emitting semiconductor device using gallium nitride compound having a double-hetero junction structure. By controlling a ratio of a hole concentration of the p-type layer and an electron concentration of the n-type layer approximates to 1, luminous intensity of the device is improved.

There is provided a light-emitting device including a second electrode which exhibits a stable behavior in a process for manufacturing a light-emitting device or during an operation of a light-emitting device. A light-emitting device includes a first compound semiconductor layer 11 with an n-type conductivity type, an active layer 12 formed on the first compound semiconductor layer 11 and composed of a compound semiconductor, a second compound semiconductor layer 13 with a p-type conductivity type formed on the active layer 12, a first electrode 15 electrically connected to the first compound semiconductor layer 11, and a second electrode 14 formed on the second compound semiconductor layer 13, wherein the second electrode 14 is composed of a titanium oxide, has an electron concentration of 4×10²¹/cm³ or more, and reflects light emitted from the active layer.

The invention discloses a double-heterojunction MOS-HEMT (metal oxide semiconductor-high electron mobility transistor) component comprising a GaN nucleating layer 9, a GaN buffer layer 8, an InGaN embedding layer 7 and a GaN channel layer 6 which are sequentially formed on a sapphire substrate 10, an AlN barrier layer 5 and an Al2O3 gate dielectric layer 4, a source electrode 1 and a drain 3 formed on the AlN barrier layer 5, and a gate electrode 2 formed on the Al2O3 gate dielectric layer 4, wherein the double-heterojunction MOS-HEMT component is characterized in that an AlN material having good heat conductivity and larger band gap is used as the barrier layer, thus reducing the self-heating effect and gate leakage current of the component and reducing the threshold voltage of the component working in a depletion mode; by using the AlN material having strong polarizability, the invention can increase the electron concentration in the channel and increase the output power of the saturation current and the component; by using the Al2O3 material deposited on the basis of the atomic layer deposition process as the gate dielectric layer, the invention can greatly reduce the gate leakage current and increase the breakdown voltage of the component; and by using the reverse polarization of the InGaN material, the invention can increase the conduction band energy of the buffer layer and reduce the current collapse effect of the component.

An Al component gradually-changed N-type LED structure and a preparation method thereof are disclosed. The Al component gradually-changed N-type LED structure successively comprises, from bottom to top, a substrate, a nucleating layer, a buffer layer, an N-type Al<Y>In<X>Ga<1-X-Y>N layer, a multi-quantum well light-emitting layer, and a P-type GaN layer. In the N-type Al<Y>In<X>Ga<1-X-Y>N layer, X is more than or equal to 0 but less than or equal to 1, and Y is more than 0 but less than 1. An Al component in an N-type GaN layer is gradually changed. The method comprises the following steps of: (1) growing the nucleating layer on a processed substrate; (2) growing a non-doped gallium nitride buffer layer on the nucleating layer; (3) growing the N-type Al<Y>In<X>Ga<1-X-Y>N layer on the buffer layer; (4) growing the multi-quantum well light-emitting layer on the N-type Al<Y>In<X>Ga<1-X-Y>N layer, wherein the multi-quantum well light-emitting layer is formed by periodically and alternately superposed InGaN potential well layers and GaN barrier layers; and (5) growing the P-type GaN layer on the multi-quantum well light-emitting layer. An N-type region is prepared by an Al component gradually-changed mode, thereby improving electron concentration and an antistatic effect, essentially improving GaN film quality, enhancing current expansion capability, and increasing light extraction efficiency.

The invention discloses a high-performance gas sensor based on a laminated structure and a preparation method for the high-performance gas sensor. The preparation method comprises the following steps: adopting stannic oxide and zinc oxide as conducting layers, using tungsten trioxide, titanium dioxide, copper oxide and cobaltous oxide as sensitive layers, and meanwhile using palladium, platinum noble metal, cadmium sulfide and a cadmium stannide sensitizer to modify the prepared sensitive layers, so as to obtain the gas sensor. According to the method, the modified gas sensitive material is placed at the top layer by a lamination manner, and can be sufficiently reacted with atmosphere in the environment, so as to improve the responsibility of the gas sensor; the material with the better conductivity is placed at the bottom layer, so that the electron concentration change in the sensitive layers can be quickly transferred to an external circuit by the material, and the response and recovery time of the gas sensor can be shortened. Therefore, the method can be used for greatly improving the performances of the gas sensor.

The invention relates to a GaN-based LED epitaxial structure with an n type GaN structure and a growing method thereof. The GaN-based LED epitaxial structure is composed of a substrate layer, a buffer layer, an n type structure, a multi-quantum well luminescent layer and a P type structure, wherein the layers are arranged successively from bottom to top. The n type structure consists of a low-Si-doped n type GaN layer with gradually changed concentration, a Si-doped n type AlGaN layer, a u type GaN layer, and a high-Si-doped n type GaN layer. Because an nAlGaN-based n type superlattice structure is inserted into the high and low doping combination unit, a defect that the luminescent voltage is reduced only by using a high nGaN doping way in the prior art is overcome; a breakthrough is provided in terms of the structural design; and with reference of the crystal growth experience of many years, the high-doped nGaN and the low-doped nGaN are utilized and cooperation with the intermediate nAlGaN layer is realized. With the method, the electron concentration is improved and thus the electronic mobility is enhanced and the luminescent voltage is reduced. Meanwhile, stability of the whole LED structure, especially parameters like the backward voltage, the antistatic capability, and electric leakage, is decided by the growth quality of the n type zone.

The present invention belongs to the detector technology field, in particular relates to a wide temperate zone terahertz wave detector and a preparation method thereof. According to the present invention, by taking an aluminum gallium nitrogen/gallium nitrogen high electron mobility field effect transistor (HEMT) as a basic structure, by the substrate and by utilizing an epitaxy method, an aluminum gallium nitrogen/gallium nitrogen layer is prepared; then an active area table-board, a gate medium, an ohmic contact window and an electrode are prepared, so that an obtained two-dimensional electron gas in the field effect transistor has the higher electron concentration and mobility, a spectral detector of realizing the high speed, high sensitivity and high signal to noise ratio detection of a THz wave on an over room temperature condition is obtained, and finally, the wide temperate zone detection of the THz wave is realized.

The invention discloses a high-strength face-centered cubic structure medium-entropy alloy and a preparation method thereof. The CoNiCu medium-entropy alloy comprises Co, Ni and Cu elements; a resultof respective comparison of different medium-entropy alloys in electron concentration and mixing enthalpy according to the Gibbs free energy and the phase formation law of the alloy shows that the CoNiCu medium-entropy alloy has the tendency to form a single-phase FCC structure, a CoNiCu medium-entropy alloy model is constructed based on the tendency, and the alloy is predicted to be a ductile material by a first-principles technique. The preparation method of the alloy comprises the following steps: batching, vacuum melting, suction casting, homogenization annealing and solid solution treatment. Co, Cr, and Cu with a purity of 99% or more are selected and are proportioned according to an equimolar ratio or an approximately equimolar ratio, the proportioned raw materials are placed in a vacuum smelting furnace and are multiply smelted, suction casting molding is carried out after the components are uniform, and the obtained casting undergoes homogenization annealing and solid solutiontreatment to obtain the CoNiCu medium-entropy alloy having a single face-centered cubic structure and having a room temperature compressive strength of above 1600 MPa and a compression ratio of above20%.

A target positioning method based on the 3D ray-tracing algorithm includes six steps: firstly, building an ionosphere electron concentration distribution as per an international reference ionosphere model; secondly, confirming space distribution of refraction indexes; thirdly, setting parameters of the 3D ray-tracing algorithm as per radar receiving signal parameters; fourthly, performing 3D ray-tracing calculation as per the setting in step 3, so as to obtain the relationship between the ray group path value and the geographical position; fifthly, processing the data obtained from step 4, so as to obtain the corresponding relation between the time delay and the geographical position; and sixthly, comparing the time delay of a receiving signal with the time delay obtained in the step 5 through calculation, so as to obtain the geographical position corresponding to the time delay of the receiving signal, and further obtain the position of the target. The method adopts the international reference ionosphere (IRI) model to build the propagation environment, simulates the electric wave propagation through adopting the 3D ray-tracing technology, can obtain the data more in conformity with the actual condition, and can be used for guiding the application of short wave detection.