120 results about "Fermi level" patented technology

A graphene photodetector of the present invention includes a gate electrode for controlling a Fermi level of graphene, wherein the gate electrode is made of ZnO. By providing the graphene photodetector of the present invention, an ultra-high-speed photodetector having a 3 dB bandwidth exceeding 200 GHz can be realized.

The invention discloses a bifunctional chiral metamaterial surface capable of switching polarization conversion and wave absorption, and belongs to the technical field of electromagnetic metamaterials. The method is used for solving the problem that most existing chiral super-structure surfaces cannot realize dynamic adjustability and quantitative controllability and cannot have dual functions of polarization conversion and wave absorption at the same time. The super-structure surface unit structure is composed of a graphene film layer, a gold-vanadium dioxide resonance layer, a silicon dielectric layer and a bottom-layer continuous gold film. Switching of two functions of polarization conversion and wave absorption is realized by changing the conductivity of vanadium dioxide; polarization conversion and dynamic regulation and control of the wave absorbing efficiency are realized by changing the Fermi level of the graphene; quantitative controllability of polarization conversion and a wave absorbing function is realized by controlling a function weighting function. Besides, the chiral super-structure surface also has the advantages of incident angle robustness, small thickness and small size, has double functions of broadband, and has potential application value in the fields of optical devices, communication equipment, biomedical sensors and the like.

The invention discloses a method for characterizing physical properties of a single-layer graphene / semiconductor heterojunction. The method comprises the following steps: providing a physical property model about a single-layer graphene-semiconductor heterojunction, wherein influence factors comprise the change of Fermi level of single-layer graphene after the heterojunction is formed and the influence of an interface state on a formation position of a contact potential difference; extracting heterojunction electrical characteristics by using a Kelvin probe force microscope; the interface layer spacing is obtained; and importing the heterojunction electrical characteristics and the interface interlayer spacing into a physical characteristic model, and analyzing to obtain physical characteristics. According to the new theoretical model and the method for realizing the nondestructive characterization of the physical characteristics of the heterojunction by using the Kelvin probe microscope based on the theoretical model, the influence of the change of the Fermi level of the single-layer graphene and the interface state on the formation position of the contact potential difference is fully considered; key interface physical properties, especially built-in potential and depletion region characteristics which are crucial to device performance, can be accurately analyzed.

The invention provides a method and device for calculating the electron spinning state of an iron-based biphase composite magnetic material, and relates to the technical field of magnetic materials. The method comprises the following steps: establishing a heterojunction model of a biphase composite magnetic material; according to the method, generalized gradient approximation in a density functional theory is adopted as an exchange-correlation functional, relaxation is carried out on atomic positions in a heterojunction model, so that the total energy of a system is the lowest, and geometric structure optimization is carried out on the heterojunction model; performing spin polarization calculation on the optimized heterojunction model to obtain spin upward state densities and spin downward state densities of different atoms in the heterojunction model, and analyzing electronic state distribution near a Fermi level; and quantitatively evaluating the magnetic characteristics of the heterojunction model according to the spin upward state density and the spin downward state density of each atom. According to the method, an interface magnetic coupling mechanism can be disclosed, and a theoretical basis can be provided for development of a high-performance magnetically controlled reactor iron core material.

The invention belongs to the field of new energy and relates to a novel electric energy acquisition technology. The non-equilibrium conductors are substances with the same Fermi level, and the contact potential generated by the non-equilibrium field effect existing between the non-equilibrium conductors with different mass and form is converted into electric energy for utilization. A medium (hereinafter referred to as an electric conduction control medium) which has electric conduction performance and controls voltage and limits electric conductivity under a certain condition is placed between conductors, good close contact is achieved between the medium and the conductors, and the result is that under the effect of the electric conduction control medium, non-equilibrium field contact potential is converted into electric energy capable of being continuously output.

The invention relates to the technical field of semiconductor materials, and discloses a Si-doped epsilon-Ga2O3 material with high conductivity and deep ultraviolet light absorption performance and a preparation method, the doping concentration of Si in the Si-doped epsilon-Ga2O3 material is 0.83 at%-2.5 at%, and Si atoms replace tetrahedral coordinated Ga (1) atoms in epsilon-Ga2O3. By accurately controlling the Si doping concentration to be 0.83-2.5 at% and enabling Si atoms to replace tetrahedral coordinated Ga (1) atoms in epsilon-Ga2O3, the electronic structure of the material is effectively improved, the Fermi level moves upwards to enter a conduction band after Si doping, and Si3s orbital electrons occupy the conduction band bottom (CBM), so that the carrier concentration is increased, the effective mass of the electrons is reduced, and the conductivity of the material is remarkably improved; tests show that compared with an intrinsic epsilon-Ga2O3 material, the conductivity of the doped material is improved by 1-3 orders of magnitude, strict requirements of high-power electronic components and the like on the conductivity of the material are met, heat loss of the electronic components due to resistance is reduced, and the working efficiency and stability of the components are improved.

The invention discloses a material classification method and device based on an ultraviolet electron spectrum, a medium and a product, and relates to the technical field of material surface science and data analysis. The method comprises the following steps: acquiring ultraviolet light electron energy spectrum data of a target material to be analyzed, and extracting a first spectrum curve from the energy spectrum data; obtaining a conductor characteristic identification result of the target material according to the first spectrum curve; under the condition of determining that the target material does not have the conductor characteristics based on the conductor characteristic identification result, extracting a second spectrum curve in a preset valence band top energy interval extending towards the negative energy direction by taking the Fermi level as a starting point from the ultraviolet light electron spectrum data, and performing multi-dimensional characteristic fusion on the second spectrum curve, generating a semiconductor characteristic identification result of the target material based on the fusion result; and determining a classification result of the target material according to the semiconductor characteristic identification result. According to the scheme, the conductive attributes of the target material can be quickly and accurately classified.

The present invention provides a surge protection element that can smoothly handle an unnecessary current produced by a harmful pulse. A surge protection element 10 is the surge protection element 10 including a first electrode 11, an n-type semiconductor layer 12, a second electrode 13 sequentially joined in a designated direction. A portion at least from any position in the n-type semiconductor layer 12 toward the second electrode 13 in the designated direction is composed of a graded composition layer 12B, whereby in a state in which a voltage is not applied, a bandgap Eg of the portion gradually increases in the designated direction, and part of a conduction level Ec exceeding a Fermi level Ef in the portion gradually increases in the designated direction.

This application relates to a P-type gallium oxide and a preparation method thereof. The preparation method of the P-type gallium oxide includes providing a substrate, the material of the substrate includes β-gallium oxide, and a co-doping of shallow-level acceptor impurities and deep-level acceptor impurities is formed on the substrate. Among them, the shallow-level acceptor impurities are elements of the same group as oxygen. When the deep-level acceptor impurities and the shallow-level acceptor impurities are co-doped, the deep-level acceptors of the deep-level acceptor impurities can combine with the acceptor levels of the shallow-level acceptor impurities, further pushing the Fermi level towards the valence band top. This combined effect significantly improves the stability of P-type conductivity of β-gallium oxide.

The invention relates to the technical scheme. The invention belongs to the field of new energy and nuclear energy battery technology. The method is a comprehensive and systematic method for directly converting radioactive substances and radiation of the radioactive substances into electric energy. The utilization of radioactive substances is the utilization of a contact potential effect existing among substances with different Fermi levels. The utilization of the radiation is the utilization of the contact potential effect of a non-Fermi level; according to the technical scheme, the contact potential effect formed by the electric potential generated by radiation rays and radiation on a polar plate is utilized, and the effect is converted into electric energy capable of being actually utilized under the action of a medium which has conductivity and controls voltage and limits conductivity under a certain condition.

The application relates to the fields of material preparation technology and radio frequency devices, in particular to a thin film substrate structure and an acoustic filter. The thin film substrate structure comprises a supporting substrate, an interface layer, an insulating layer and a functional layer; the supporting substrate has opposite first and second surfaces, and the interface layer is located on the second surface; the insulating layer is located on the side surface of the interface layer away from the supporting substrate; the functional layer is located on the side surface of the insulating layer away from the supporting substrate; and the interface layer has at least one of a deep energy level defect and a preset band gap width. The application plays a pinning effect on the Fermi level of the device by the interface layer having at least one of a deep energy level defect and a preset band gap width. The surface local conductance effect of the supporting substrate when working at a high frequency is effectively inhibited, the generation of high-order harmonics is inhibited, and the linearity of the device is optimized.

The invention relates to the technical field of photocatalysis, in particular to an I-type p-n heterojunction photocatalyst as well as a preparation method and application thereof. According to the photocatalyst, an n-type semiconductor metal organic framework NUS-8 is used as a matrix, a p-type semiconductor CuO is loaded, and an I-type p-n heterojunction structure is constructed. The preparation method comprises the following steps: by taking NUS-8 and cupric salt as raw materials and N, N-dimethylformamide as a dispersion medium, performing coordination anchoring on Cu < 2 + > on the surface of NUS-8 under solvothermal, oxidizing to form CuO nanoparticles, and constructing a coupling interface to obtain the photocatalyst. An energy band of the material is in I-type (straddling type) arrangement, a built-in electric field is formed by Fermi level difference at an interface, directional separation and migration of photo-induced electrons and holes are effectively driven, and the catalytic activity and stability of a photocatalytic reaction are remarkably improved. The material has the advantages of simple and convenient process, stable structure, excellent photocatalytic performance and the like, and is suitable for environment and energy related fields such as photocatalytic CO2 reduction and the like.

The present invention provides a quantum device and a method for manufacturing the same that enable the injection of Cooper pairs into the edges of a two-dimensional topological insulator without the use of heterointerfaces, and the control of the Fermi level at the edges of the two-dimensional topological insulator. [Solution] The quantum device comprises a monolayer 4 of tungsten ditelluride having a 1T' type crystal structure, a first electrode 6a that provides a first potential to a first portion of the monolayer that is a part of the monolayer and separated from the outer periphery of the monolayer, and a second electrode 6b that provides a second potential to a second portion of the monolayer that is a part of the monolayer and includes a certain range of the outer periphery of the monolayer. The first electrode is positioned so that Cooper pairs generated by the application of the first potential to the first portion can penetrate a third portion that is a part of the second portion and includes the certain range. The third portion is a region in which topological superconductivity occurs when Cooper pairs penetrate.

The invention discloses a fine simulation method of a CdTe-based II-VI group compound thin film solar cell and a cell structure designed based on the method. According to the method, a physical model of a CdTe-based battery is established through numerical simulation, then the energy band structure of a carrier transport layer is systematically optimized, and the quantitative criteria that a hole transport layer needs to meet the requirements that the Fermi energy level is lower than that of an absorption layer and the hole transport layer has enough positive conduction band offset and an electron transport layer needs to have a wide band gap and moderate positive conduction band offset are determined. And for the optical layer, the optimal thickness of the antireflection layer is determined, the enhancement effect of the optical path gain of the textured structure on optical absorption is quantified, and the maximization of the light capture efficiency is realized. According to the method, through electrical-optical coupling simulation, the CdTe-based solar cell structure of which the conversion efficiency is remarkably improved can be accurately predicted and guided to be designed, the defects that a traditional experiment is high in trial and error cost and long in period are effectively overcome, and a reliable theoretical design and optimization tool is provided for research and development of a high-efficiency and low-cost CdTe-based solar cell.

The present invention discloses an ultra-narrowband absorber tunable from visible to mid-infrared, and its structure includes a substrate, a bottom Bragg reflector, a resonant cavity layer, a lower electrode, a dielectric spacer layer, an upper electrode, a bilayer graphene structure capable of mutual electrostatic gating, and a top Bragg reflector. The absorber is based on Fabry-Perot cavity resonance to form a resonance mode within the resonant cavity layer between the bottom and top Bragg reflectors. The radiation loss rate of this resonance mode is mainly determined by the constituent components, the number of periods of the Bragg reflector, and the Fermi level of graphene together, while the absorption loss rate is determined by the Fermi level of graphene. The bandwidth of the resonance mode is jointly determined by the magnitudes of the radiation loss rate and the absorption loss rate. By constructing a Bragg reflector with appropriate components and number of periods and regulating the Fermi level of graphene to make the system reach critical coupling, an ultra-narrowband perfect absorption tunable from visible to mid-infrared can be achieved.

The invention provides an n-type Mg3Bi2-based composite thermoelectric material as well as a preparation method and application thereof, the chemical composition of the n-type Mg3Bi2-based composite thermoelectric material is Mg 3.2 (Bi 0.7 Sb 0.3) 1.99 Te 0.01-Q2Se x wt%, Q is Cu and / or Ag element, and the sum of x wt% and x wt% is 100%. X is 0.0 lt; and x is less than or equal to 1.5. The invention also discloses a preparation method and application of the n-type Mg3Bi2-based composite thermoelectric material. The Fermi level of the n-type Mg3Bi2-based composite thermoelectric material goes deep into a conduction band, the electrical property is excellent, and the power factor is kept at a high level; the total thermal conductivity is reduced, so that the thermoelectric figure of merit of the n-type Mg3Bi2-based thermoelectric material is remarkably improved, and the n-type Mg3Bi2-based thermoelectric material has a wide application prospect in the field of semiconductor thermoelectric materials.

This invention discloses a ferroelectric transistor capable of generating thousands of polarization states and its fabrication and application method. The ferroelectric transistor is fabricated based on a Gr / hBN heterojunction, with a Gr sheet as the top layer and an hBN sheet as the bottom layer. The rotation angle between Gr and hBN is controlled within 1° using a dry transfer method. The Gr / hBN heterojunction is fixed on a silicon substrate (SiO2 / Si). Source and drain electrodes are further deposited using electron beam lithography and electron beam evaporation processes to construct the Gr / hBN ferroelectric transistor. A single device can generate dozens of discrete polarization states through source-drain pulse modulation. Simultaneously, by superimposing a gate voltage while applying source-drain pulses, the Fermi level of graphene can be reversibly tuned between dozens of non-volatile doping levels, and the polarization state can be modulated by source-drain pulses at each doping level. The number of stable polarization states reaches thousands at room temperature; different polarization states can be retained for more than 10^6 times. 5 Seconds, and based on linear extrapolation, it could last for more than 10 years.

A method for forming a semiconductor structure, comprising: providing a substrate, including a substrate and a fin standing on the substrate, along the extension direction of the fin, the fin includes a channel region, the channel region is used to form a stacked work function layer; forming a gate dielectric layer conformally covering the top and sidewall of the fin in the channel region; forming a first work function layer conformally covering the gate dielectric layer in the channel region; forming a filling layer on the first work function layer between adjacent fins, the filling layer exposes at least the first work function layer on the top of the fin, the Fermi level of the material of the filling layer is closer to the Fermi level of the fin than the Fermi level of the material of the stacked work function layer; forming a second work function layer covering the first work function layer and the filling layer, the second work function layer and the first work function layer are used to constitute the stacked work function layer. The second work function layer is located on the top of the first work function layer and the filling layer, which reduces the probability of generating void defects in the second work function layer and improves the uniformity of the threshold voltage of the device.

The embodiment of the present application discloses a kind of transmission type terahertz absorption structure and preparation method thereof.Transmission type terahertz absorption structure includes at least one transmission type terahertz absorption composite film layer, transmission type terahertz absorption composite film layer includes substrate and the metal grating layer, insulating layer and graphene layer that are sequentially stacked in substrate side;Wherein metal grating layer and graphene layer are electrically connected with external power supply.The technical scheme of the embodiment of the present application is based on electromagnetic wave theory and the electrical properties of graphene, by additional voltage control Fermi level of graphene, adjust the absorption of absorption structure to terahertz, make the terahertz wave that pass through the present absorption structure have different intensity information under the influence of external voltage, play the role of switch, and have the advantages of active regulation, real-time control, accurate control, suitable for terahertz spectrum imaging analysis, single-pixel imaging and spectrum measurement etc.

The gallium nitride semiconductor purple light laser comprises a substrate, a lower coating layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper coating layer which are sequentially arranged from bottom to top. According to the gallium nitride semiconductor purple light laser, the distribution characteristic of the drift rate of saturated electrons in the lower waveguide layer of the gallium nitride semiconductor purple light laser is specifically designed, so that the lower waveguide layer forms a carrier pinning lower waveguide layer, redundant carriers are limited in an active region under the condition of large injection, electron leakage current is eliminated, the carrier transport and injection efficiency is improved, and the quantum efficiency is improved. The bipolar conductance effect and the junction voltage saturation at the threshold are inhibited, and the series resistance and voltage are reduced; meanwhile, an acceleration hole and an electronic quasi-Fermi level are pinned, and the rate of stimulated radiation exceeding spontaneous radiation is accelerated, so that carriers are completely converted into photons to be output, symmetry breaking corresponding to a far-equilibrium state is inhibited, a deep level trap of a lower waveguide layer is reduced, and the capture effect of a depletion region is enhanced. And the problems of junction voltage jump and series resistor sinking are solved.

A semiconductor device includes a semiconductor region made of a material to which conductive impurities are added, an insulating film formed on a surface of the semiconductor region, and an electroconductive gate electrode formed on the insulating film. The gate electrode is made of a material whose Fermi level is closer to a Fermi level of the semiconductor region than a Fermi level of Si in at least a portion contiguous to the insulating film.

The invention discloses a terahertz detector based on a Dirac semimetal nanowire structure, and particularly relates to the terahertz field, the terahertz detector comprises a gold reflecting layer, a dielectric layer and a Dirac semimetal material layer, the dielectric layer is arranged on the top of the gold reflecting layer, and the Dirac semimetal material layer is arranged on the top of the dielectric layer; and the Dirac semi-metal material layer is a Dirac semi-metal nanowire array layer. A Dirac semimetal-silicon dioxide-gold three-layer structure is adopted, Fano resonance and F-P resonance are excited to be coupled through a nanowire array, high absorption (99.02% at most) of seven frequency bands within the range of 0-14.5 THz is achieved, dynamic tuning is achieved by adjusting the Fermi level of Dirac semimetal, the sensitivity reaches 5421.43 GHz / RIU, the quality factor is 35.204 (1 / RIU), and the device is stable in structure, easy to process and suitable for large-scale production. The device is suitable for the fields of terahertz detection, imaging, biosensing and the like.

The invention discloses an adjustable ultra-wideband terahertz metamaterial wave absorber, and belongs to the technical field of terahertz wave absorbers. The wave absorber is composed of a plurality of same metamaterial structure units which are periodically arranged, and each metamaterial structure unit is made of three layers of composite materials, wherein the first layer is a graphene pattern layer, the second layer is a polyimide dielectric layer, and the third layer is a copper reflecting layer. Wherein the graphene pattern layer adopts a combined design of four groups of square and L-shaped structures, and the four groups of structures form a biaxial symmetry layout through geometric coupling. The structure has the characteristics of wide absorption bandwidth, high absorption rate and dynamic adjustability, can realize more than 90% of efficient absorption in the frequency band of 2.28-4.68 THz, and can adjust the Fermi level of the graphene by externally applying bias voltage to realize rapid switching between the absorption state and the reflection state. The device is suitable for various application scenes such as terahertz communication, sensing and stealth.

The application provides a fin field effect transistor and a preparation method thereof. A gate dielectric layer of the fin field effect transistor comprises an aluminum oxide layer and a hafnium oxynitride layer covering the aluminum oxide layer. The aluminum oxide layer can form a good interface with a semiconductor substrate, thereby providing a good interface basis for the hafnium oxynitride layer, preventing crystalline epitaxy of the hafnium oxynitride layer, and reducing interface state density between the gate dielectric layer and the semiconductor substrate. The aluminum oxide layer and the hafnium oxynitride layer can cooperate to reduce loss in a carrier movement process, adjust a Fermi level of the gate dielectric layer, thereby reducing leakage current between the gate dielectric layer and the semiconductor substrate, and improving reliability of the device.

The invention discloses a passivation material, the structural formula of the passivation material is shown in the specification, X is independently selected from F, Cl, Br or I, and Y is independently selected from-PO3H2,-SO4H,-COOH,-OH or-SH. The passivation material and uncoordinated Pb < + > on the surface of the perovskite can form a powerful double-site coordination effect, the interface defect state density is remarkably reduced, and non-radiative recombination is inhibited. Meanwhile, the interface energy band structure is effectively regulated and controlled, the Fermi level is moved upwards, the surface n-type characteristic is enhanced, and therefore energy level alignment is optimized, the electron extraction potential barrier is reduced, and the charge transmission efficiency is improved.

The application discloses a humidity sensor and a preparation method thereof. The humidity sensor comprises an insulating substrate, an electrode layer arranged on the insulating substrate, a two-dimensional transition metal sulfide layer and a two-dimensional transition metal oxide layer. The two-dimensional transition metal oxide layer is combined on the two-dimensional transition metal sulfide layer, and the two form a composite structure. The two-dimensional transition metal oxide layer and the two-dimensional transition metal sulfide layer have a Fermi energy level difference capable of causing charge transfer, thereby forming a space charge region and a potential barrier at the interface of the composite structure. The humidity sensor has high sensitivity, stability and corrosion resistance, and the working temperature and humidity range are also improved.

The present invention relates to a transient voltage detection method based on an array-type quantum spin Hall effect insulator material. The present invention belongs to the field of new electronic materials and provides a transient voltage detection method, which can realize the measurement of transient voltage within the accuracy of electronic response time. The main scheme includes: step 1: using the first principle calculation to determine the quantum spin Hall effect insulator material with different band gaps, and selecting the ordinary layered insulator material with lattice matching, calculating the band structure and analyzing the behavior of electrons and holes near its Fermi level; step 2: through the interlayer van der Waals effect, the calculated quantum spin Hall effect insulator material with different band gaps is lattice matched with the ordinary insulator material, and built into a multilayer material unit stacked in sequence, and the phonon dispersion of the multilayer material unit is calculated to detect its dynamic stability; step 3: the stable multilayer material unit is combined into an array sensor, prepared by chemical vapor deposition, and the performance parameters of the sensor array are tested.

The application provides a multi-polarization non-reciprocal metamaterial coherent wave absorber based on temperature control and electric control cooperation, each wave absorber unit comprising two metal layers etched with quasi-# Chinese character-shaped slots arranged in an up-down mode and a metal layer with a C-shaped slot located in the middle, and a graphene grating located between adjacent metal layers, and part positions in the two quasi-# Chinese character-shaped slots being filled with a phase change material to form a composite structure with the metal layer. The application realizes conversion of the metal-insulating state of the phase change material by controlling the temperature of the phase change material, and adjusts the Fermi level of the graphene grating by controlling the bias voltage of the graphene grating, thereby realizing x-polarization and x-polarization same-polarization reciprocal coherent wave absorption, x-polarization and y-polarization cross-polarization non-reciprocal coherent wave absorption in a frequency band, and realizing y-polarization and y-polarization same-polarization reciprocal coherent wave absorption, y-polarization and x-polarization cross-polarization non-reciprocal coherent wave absorption in another frequency band, so that the application range is effectively widened.

This disclosure provides a semiconductor quantum dot feedback control method and system based on FPGA. The method includes: S1: performing linear scanning and acquiring response data of a single-electron transistor under different bias voltages; S2: determining the operating point with the steepest transconductance by optimization and outputting the optimal bias voltage corresponding to the operating point to lock the optimal operating point of the single-electron transistor; S3: extracting the high and low level distribution characteristics of random telegraph signals by acquiring signal data of the single-electron transistor in real time; S4: dynamically adjusting the bias voltage applied to the quantum dot according to the high and low level distribution characteristics to calibrate the offset between the quantum dot energy level and the source-drain Fermi level.

The present invention relates to an iron oxide-coated carbon microtube and its application in terahertz wave absorption. The carbon microtube is a helical structure formed by continuous high-temperature carbonization and curling of biomass carbon fiber, and a layer of iron oxide nanosheets is coated on its surface by a hydrothermal method. The present invention constructs a unique heterostructure composite by combining the (110) plane of iron oxide with the carbon microtube. Due to the energy level matching between the Fermi level of the carbon microtube and the conduction band of iron oxide, the periodic injection and release of electrons on the carbon microtube to the iron oxide nanosheets are promoted under the radiation of periodic terahertz waves, realizing the inversion of Fe(III) and Fe(III<supgt;‑< / supgt;). The polarization relaxation induced by the valence inversion significantly enhances the terahertz wave absorption performance, and the highest absorption shielding efficiency at a frequency of 1.39 THz is up to 96.72 dB. This material has the advantages of light weight, ultrathin and strong absorption, and has important value in the fields of terahertz signal shielding of microelectronic devices, stealth coatings, etc.