13 results about "Electron concentration" patented technology

According to the deep ultraviolet laser epitaxial structure and the epitaxial growth method thereof provided by the invention, the Al component of the first waveguide layer is linearly and progressively increased from the side close to the electron injection layer to the side close to the quantum well active layer; or the Al component of the second waveguide layer is linearly and progressively decreased from the side close to the quantum well active layer to the side close to the hole injection layer to form refractive index distribution which takes the barrier layer of the quantum well active layer as the highest refractive index point and gradually decreases towards one side (the n-type side or the p-type side), so that the light field is firmly bound near the quantum well active layer, and the light limiting capability is remarkably enhanced; meanwhile, high-low Al components of the p-type side (the second waveguide layer) gradually change to generate a strong polarization electric field, ionization of a p-type doped acceptor (such as Mg) can be promoted, two-dimensional hole gas (2DHG) can be induced, and the hole concentration is improved; the low-high Al components of the n-type side (the first waveguide layer) are gradually changed, so that two-dimensional electron gas can be induced, and the electron concentration is improved.

The application belongs to the technical field of sensors, and discloses an ammonia gas-sensitive sensor and a preparation method thereof. The ammonia gas-sensitive sensor comprises an insulating substrate and an interdigital electrode, wherein: the interdigital electrode is arranged on the insulating substrate, and the surfaces of the interdigital electrode and the insulating substrate are both coated with a gas-sensitive coating; the raw material for preparing the gas-sensitive coating comprises a gas-sensitive material, and the chemical general formula of the gas-sensitive material is: Ba 1‑x Y x TiO3, wherein 0.002<=x<=0.01. The application introduces specific rare earth ions Y 3+ into the A-site of the BaTiO3 lattice for donor doping, utilizes Y 3+ to replace Ba 2+ , and generates a donor doping effect, which increases the free electron concentration in the conduction band of the material, not only significantly improves the initial conductivity of the material in the air, and provides an excellent signal base for resistance change, but also optimizes the concentration and activity of the surface adsorbed oxygen of the material, and realizes high-sensitivity and selectivity detection of ammonia gas.

The invention discloses a light-emitting chip and a manufacturing method thereof. The light-emitting chip comprises at least one light-emitting unit and an atom repairing layer. The light-emitting unit comprises an epitaxial layer, the epitaxial layer comprises an etching surface, and the atomic repair layer at least partially covers the etching surface; the atom repairing layer is used for providing atoms for the etching surface, so that the atom repairing layer can provide atoms for the epitaxial layer and repair holes in the epitaxial layer, namely, hole filling is carried out on the epitaxial layer, and therefore, the phenomena of high-density dislocation and non-radiative recombination center generated when the epitaxial layer is etched can be improved; the phenomenon that electrons in the light-emitting unit are leaked from the side wall of the epitaxial layer is reduced, the electron concentration in the light-emitting unit is improved, and then the photoelectric conversion efficiency of the light-emitting unit can be improved, namely the light-emitting efficiency of the light-emitting chip is improved.

This invention relates to the field of silicon carbide technology and discloses a method for measuring the nitrogen concentration of a silicon carbide wafer, which involves calculating the first contact potential φ on the surface of the silicon carbide wafer. sample Then, by establishing the first contact potential φ sample The difference between the conduction band bottom energy Ec and the Fermi level energy Ef of a silicon carbide wafer is obtained by establishing the first relationship between the difference between the conduction band bottom energy Ec and the Fermi level energy Ef. The specific value of the electron concentration n at equilibrium is then obtained by establishing the second relationship between the electron concentration n at equilibrium and the nitrogen concentration N. D The third relation yields the specific value of the nitrogen concentration n in the silicon carbide wafer; this allows the nitrogen content of silicon carbide to be obtained through surface potential testing, facilitating the production process and improving testing efficiency.

The application provides an n-type SmMg2Sb2-based thermoelectric material and a preparation method thereof, and the chemical general formula of the n-type SmMg2Sb2-based thermoelectric material is SmMg 2.3 Sb 2‑x‑y Bi y Te x , 0 < x < 0.03, 0 < y < 0.5. The SmMg2Sb2-based thermoelectric material of the technical scheme has a lower intrinsic hole concentration, and the hole concentration is about 4*10 16 cm ‑3 -3 cm-1 at room temperature. Meanwhile, the electron mobility is 220% higher than the hole mobility, the electron concentration and the hole concentration are relatively small at high temperature (>600 K), the material presents n-type conductive characteristics, and the state density effective mass is 2.6 m 0, which is higher than all reported p-type AB2X2 alloys.

The present application relates to the technical field of plasma analysis, and discloses a dust plasma parameter inversion method, which comprises the following steps: firstly, measuring the attenuation coefficient of dust plasma to microwaves through experimental measurement; secondly, inversely deducing the dielectric coefficient and conductivity of dust plasma from the attenuation coefficient calculation formula; thirdly, substituting the deduced result into the dust plasma dielectric coefficient and conductivity calculation formula to obtain the electron concentration, dust particle concentration and dust particle radius in the dust plasma; and finally, verifying the reliability of the inversion result. The present application is based on the microwave transmission theory and experimental research of dust plasma, verifies and perfects the related theory, and proposes a measurement method of internal parameters of dust plasma, which has practical significance for further exploring the radio physics problems in dust plasma.

The surfaces of epitaxial source and drain regions of NMOS (n-type metal-oxide-semiconductor) transistors are heavily doped with an n-type chalcogen (e.g., tellurium, selenium, sulfur) to overcome the limitations of low-ionization-energy n-type dopants (e.g., phosphorus, arsenic, antimony) on free electron concentrations due to Fermi-level pinning. The chalcogen can be introduced into the source and drain regions by diffusion from a chalcogen-rich metal contact layer or by chemical vapor deposition (CVD) processes in which a chalcogen precursor flows over the source and drain regions after its formation. In some embodiments, the CVD process may involve silicon and chalcogen precursors flowing over the surface of the source and drain regions to form a thin layer of silicon heavily doped with a chalcogen.

The invention provides a chemical reduction reaction strengthening system and method utilizing hot electron emission injection, and belongs to the technical field of energy conversion and chemical engineering. The system comprises a thermionic emission unit and a chemical reaction unit which are communicated with each other, the hot electron emission unit is connected with the electron detection regulation and control unit, and the electron detection regulation and control unit comprises a current detection device; the chemical reaction unit comprises a reaction system cavity, and the reaction system cavity is communicated with the product collecting unit; the thermionic emission unit comprises thermionic emission materials, the thermionic emission materials are arranged above the reaction system containing cavity, and the reaction system containing cavity is communicated with the vacuum device. The electron concentration in a chemical reduction reaction system is increased in a direct electron injection mode, and the reduction reaction can be directly carried out under the impact of hot electrons. Reaction products are continuously collected through the product collecting unit, reaction driving force is maintained, and the reaction is continuously and efficiently carried out.

The invention discloses a simulation analysis method for a current collapse effect of a p-type gate GaN HEMT device under high pressure stress. The method comprises the following steps: firstly, constructing a two-dimensional model based on device process parameters, carrying out fine grid division, calibrating an electrical characteristic model through TCAD simulation, setting an acceptor type body trap on a buffer layer, and setting an acceptor type interface trap on an interface; a time model is introduced to dynamically apply bias voltage, the constant voltage of the grid electrode is 3V, the voltage of the drain electrode is 5V for 1ms, then the voltage of the drain electrode is 25V for 1ms, and then the drain electrode is recovered to 5V, and time-domain characteristics of drain electrode current are obtained through simulation; through combination of electron concentration distribution, a conduction band energy diagram and 2DEG electron concentration change, a degradation mechanism of current collapse caused by a virtual gate effect formed by the fact that electrons break away from a heterojunction potential well and enter a buffer layer under high pressure stress is disclosed. According to the method, the current collapse effect is dynamically analyzed from the microcosmic physical process, and an accurate basis is provided for reliability evaluation of the device.

The application discloses an AlGaN device structure and a manufacturing method and an etching method thereof. The AlGaN device structure is provided with an AlN template layer between a sapphire substrate and a buffer layer, the AlN template layer is formed on the sapphire substrate after high-temperature sputtering and ultra-high-temperature annealing treatment; and a low-Al-component AlGaN sacrificial layer is arranged between a high-Al-component AlGaN high-resistance layer and the buffer layer; the Al component of the high-Al-component AlGaN high-resistance layer is not less than 0.5; the Al component of the low-Al-component AlGaN sacrificial layer is less than 0.4, and the free electron concentration of the low-Al-component AlGaN sacrificial layer is not less than 5*10 18 cm ‑3 -2. Therefore, cracks of the AlGaN device can be avoided by balancing tensile strain and compressive strain; and the substrate can be peeled off by an electrochemical peeling method.

According to the semiconductor laser element and the light emitting device, an electron providing layer is inserted between a first cladding layer and a first waveguide layer, the thickness of the electron providing layer is smaller than or equal to 100 nm, and the n-type doping concentration of the electron providing layer is larger than or equal to 3 * 1018 atom / cm < 3 >. The electron concentration is improved through high Si doping, and effective injection of electrons from the n-type layer to the active region is promoted, so that the recombination probability of carriers in the laser active region is effectively increased, and the overall efficiency of the laser is further improved. And meanwhile, the thickness of the electron providing layer is thinned and accurately controlled, so that the negative influence of high Si doping on the photoelectric property of the laser device is reduced as much as possible while the limitation factor is improved, the probability of generating crystal structure defects is reduced, the performance stability of the laser element is ensured, and the purpose of improving the brightness of emergent light is finally achieved.

The invention discloses an ablation modeling method and device, electronic equipment and a computer program product. The method comprises the steps that the crystal structure of a to-be-ablated material is obtained, and the to-be-ablated material is a lattice material doped with impurity atoms; analyzing the crystal structure to obtain an energy band structure, optical characteristic parameters and thermophysical parameters of the material to be ablated; analyzing the energy band structure and the optical characteristic parameters by adopting a Foke-Planck equation to obtain the critical free electron concentration of the to-be-ablated material; analyzing the critical free electron concentration by adopting a double-temperature model to obtain a laser energy density parameter of the laser suitable for the material to be ablated; and analyzing the laser energy density parameter and the thermophysical parameter by adopting a finite element method to obtain the ablation simulation morphology of the to-be-ablated material. The femtosecond laser ablation modeling method solves the technical problem that existing femtosecond laser ablation modeling of doped crystal lattices is insufficient in ablation modeling precision.

This invention belongs to the field of metallic materials technology, specifically a TiZrMo-based refractory high-entropy alloy and its preparation method. The refractory high-entropy alloy is composed of any two of Al, Cr, and Nb, and Ti, Zr, and Mo. The atomic radius difference δ of the refractory high-entropy alloy is ≤6.6%, the alloy entropy enthalpy ratio Ω is ≥1.1, and the mixing enthalpy ΔH is... mix The energy density ranges from -18.0 to 4.0 kJ / mol, and the vacancy electron concentration (VEC) is <6.87. Furthermore, the preparation method of this invention has the advantages of simple steps, easily controllable composition, high production efficiency, and near-net-shape forming. The prepared refractory high-entropy alloy has a stable microstructure and a density of less than 7.00 g / cm³. 3 It has a Vickers hardness greater than 1400 HV, a room temperature compressive strength consistently above 980 MPa, an elongation at break greater than 10.8%, and an oxidation weight gain of less than 15.00 mg / cm³ at 800℃ for 12 hours. 2 It is low in cost and easy to apply on a large scale in industrial applications.