63results about How to "Reduce defect density" patented technology

The utility model relates to the technical field of mobile phone heat dissipation films, in particular to a high-heat-conduction mobile phone middle frame graphite heat dissipation film which comprises a heat dissipation film body, the heat dissipation film body sequentially comprises matte black single-faced adhesive tape, a high-heat-conduction graphite layer and double-faced adhesive tape from top to bottom, the high-heat-conduction graphite layer is formed by stacking low-temperature carbonization layers and is 0.2 mm in thickness, and the high-heat-conduction graphite layer is formed by stacking low-temperature carbonization layers. The low-temperature carbonization layer is formed by graphene through low-temperature carbonization treatment, the heat conductivity coefficient reaches 2000-2100 W / M.K, energy consumption is reduced through low-temperature treatment, the production cost is indirectly reduced due to the low temperature requirement, the graphene is subjected to low-temperature carbonization treatment, the lattice defect density is reduced, and the stability of the heat conductivity coefficient is ensured; and meanwhile, the 0.2 mm high-thermal-conductivity graphite layer is formed by stacking the low-temperature carbonization layers, so that the occupied space of the heat dissipation film body in the middle frame is reduced.

The application provides a kind of passivation material, passivation layer and perovskite solar cell, with general structure as shown in formula I: X1, X2, X3, X4, X5, X6, X7, X8, X9, X 10 Each independently selected from C or N, and at least one selected from N; R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each independently selected from H, C1-C5 alkyl, C1-C5 alkyl nitrile or C1-C5 alkyl hydroxyl, and at least one selected from alkyl nitrile or alkyl hydroxyl. The perovskite solar cell using the passivation layer defined in the application has better fill factor and photoelectric conversion efficiency.

The application relates to the technical field of nanomaterial preparation, and particularly discloses a carbon nanotube preparation method based on carbon source and plasma time sequence cooperation and a carbon nanotube. In the gas phase deposition process, carbon source gas is input in a pulse mode, and a pulse type plasma is synchronously applied, wherein the carbon source input pulse and the plasma output pulse are time-differently matched, the carbon source supply window and the plasma action window form a non-fully-synchronized time sequence coupling relationship, the carbon source activation, transportation, deposition and structure reconstruction process are controlled in the time dimension, and meanwhile, the carbon source gas is introduced from a position close to the plasma action area to maintain the pulse opening and closing characteristics. The method can improve the growth selectivity of the carbon nanotube, reduce the defect density, and is suitable for controllable preparation of single-wall carbon nanotubes. The single-wall carbon nanotube with a semiconductor content greater than or equal to 83% can be prepared with high selectivity, and the product has the advantages of few defects, high purity and high yield.

The application discloses a preparation method of a sodium ion battery hard carbon negative electrode material based on step-by-step synergistic regulation, and comprises the following steps: S1, biomass pretreatment; S2, low-temperature pre-carbonization to obtain biomass pre-carbonized carbon; S3, physical activation: the pre-carbonized carbon is placed in an activation atmosphere to perform medium-temperature activation, and biomass activated carbon is obtained; S4, high-temperature carbonization: the biomass activated carbon is placed in an inert atmosphere to perform high-temperature carbonization, and a hard carbon intermediate is obtained; S5, chemical vapor deposition coating: the hard carbon intermediate is placed in a mixed atmosphere of a coating carbon source and an inert gas to perform chemical vapor deposition coating, and a surface-coated biomass hard carbon negative electrode material is obtained. The application can realize a higher closed pore volume at a milder temperature, and the synergistic regulation pore forming mode of activating and forming pores first and then high-temperature closing pores also avoids the insufficient closed pores caused by single high-temperature treatment.

This invention discloses a method for preparing a partitioned buffer layer, a patterned composite substrate, and the same method. The preparation method includes: providing a patterned substrate; the three-dimensional pattern on the surface of the patterned substrate has inclined sidewalls, and gap planes exist between adjacent three-dimensional patterns; forming an argon ion accumulation layer, utilizing the repulsive effect between argon ions to bombard the patterned substrate, making the inclined sidewalls positively charged; sputtering negatively charged aluminum atoms that electrostatically adsorb onto the inclined sidewalls to form an aluminum atom thin film; the sputtered aluminum atoms react with at least nitrogen gas to form a first thin film on the gap plane, and the aluminum atom thin film reacts with nitrogen and oxygen gas to form a second thin film on the inclined sidewalls; the first and second thin films constitute a buffer layer. This invention achieves partitioned film formation of a buffer layer on a patterned substrate, where the film elements, proportions, and crystal quality differ and are controllable in different regions, effectively matching the stress and crystal quality during epitaxial growth and reducing defect density.

The embodiment of the utility model provides an epitaxial layer structure of a gallium nitride power device. The epitaxial layer structure comprises a substrate, a high-resistance structural layer, a high-resistance GaN layer, a channel layer and a barrier layer which are sequentially stacked from bottom to top, the high-resistance structural layer comprises a Si-containing material layer and an Al-containing material layer, and the Al-containing material layer is located between the high-resistance GaN and the Si-containing material layer; the constituent elements of the Al-containing material layer comprise Al and N; and the high-resistance GaN layer is a non-doped layer. According to the epitaxial layer structure of the gallium nitride power device, through matching of the Si-containing material layer and the Al-containing material layer, the resistance of the gallium nitride layer is improved, the voltage withstanding characteristic of the gallium nitride device is improved, and meanwhile side effects caused by additional doping are avoided.

The invention provides a preparation method of a tin-doped scaly nano gallium oxide thin film solar blind ultraviolet photoelectric detector. The preparation method comprises the following steps: carrying out cleaning pretreatment on a single crystal GaN substrate; depositing an Au thin film on the pretreated single crystal GaN substrate to serve as a catalyst layer; the preparation method comprises the following steps: mixing Ga2O3, diamond and SnO2 powder according to a certain mass ratio to prepare a precursor; putting the single crystal GaN substrate deposited with the Au thin film and a precursor into a CVD furnace, and growing according to preset gas flow, pressure intensity, reaction temperature and reaction time to obtain a tin-doped scaly nano gallium oxide thin film; and respectively preparing electrodes on the surface of the tin-doped scaly nano gallium oxide thin film and the surface of the GaN substrate by adopting a radio frequency magnetron sputtering method. The conductivity of the thin film is improved through tin doping, the specific surface area and light absorption are increased through the scaly nanostructure, high-performance deep ultraviolet photoelectric detection is achieved, and the technical problem that in the prior art, the dark current of a device is high is solved.

This invention provides a light-emitting diode epitaxial wafer and its fabrication method. The light-emitting diode epitaxial wafer includes a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multiple quantum well layer, an electron blocking layer, and a P-type GaN layer sequentially deposited on the substrate. The buffer layer includes a nitrided graphene buffer layer, an h-BN buffer layer, and a B-type GaN layer sequentially deposited on the substrate. x Al 1‑x N buffer layer, AlN buffer layer, wherein, the B x Al 1‑x The boron content in the N-buffer layer gradually decreases along the growth direction of the epitaxial layer. This invention achieves this by sequentially arranging a graphene nitride buffer layer, an h-BN buffer layer, and a boron buffer layer between the substrate and the epitaxial structure. x Al 1‑x N-buffer layers and AlN-buffer layers reduce lattice mismatch between structures, lower defect density, and improve the overall quality of LED epitaxial wafers.

This application relates to the field of two-dimensional semiconductor material preparation technology, specifically to a method for preparing monolayer molybdenum disulfide by dual-sulfur source chemical vapor deposition, comprising the following steps: Step 1, providing a chemical vapor deposition reaction chamber having an upstream region, a growth region, and a downstream region; Step 2, arranging a molybdenum-containing precursor in the growth region, and arranging a substrate above or opposite to the molybdenum-containing precursor; Step 3, arranging a first sulfur-containing precursor in the upstream region and a second sulfur-containing precursor in the downstream region; Step 4, introducing a carrier gas into the reaction chamber and heating it to cause the first sulfur-containing precursor, the second sulfur-containing precursor, and the molybdenum-containing precursor to volatilize and undergo a chemical vapor deposition reaction on the substrate surface to form a monolayer molybdenum disulfide. This invention employs a dual-sulfur source strategy, achieving large-size, uniform, and low-defect preparation of monolayer MoS2, facilitating widespread application.

The invention relates to the technical field of organic synthesis, in particular to a small-molecule electron transport material containing a naphthalimide terminal group and preparation and application thereof.4-bromo-1, 8-naphthalic anhydride is used as a raw material, brominated naphthalimide terminal groups are obtained through imidization, then different conjugated fused ring core units are used as raw materials, and the small-molecule electron transport material containing the naphthalimide terminal group is prepared through a one-step method. And coupling the conjugated fused ring core unit with naphthalimide through a coupling reaction to obtain the small-molecule electron transport material containing the naphthalimide terminal group. By virtue of high electron affinity, strong electron withdrawing property, good thermal stability and morphological stability and relatively strong designability of structure and function of naphthalimide, the micromolecule electron transport material shows excellent electron mobility, tight intermolecular accumulation and good three-dimensional charge transport characteristic; surface / interface defects can be effectively passivated, trap-assisted recombination is inhibited, and the photoelectric conversion efficiency and the stability of the perovskite solar cell are synergistically improved.

The invention discloses a preparation method of an efficient light-emitting silver-indium-sulfur and silver-indium-zinc-sulfur composite nano material, and belongs to the technical field of light-emitting nano materials and preparation. The preparation method comprises the following steps: by taking silver dibutyl dithiocarbamate, indium dibutyl dithiocarbamate and zinc carboxylate as precursors, uniformly mixing at a dodecane neutralization pretreatment temperature to form a mixed solution A; naturally cooling, adding dodecanethiol, and uniformly stirring and mixing to obtain a mixed solution B; at the reaction temperature, decomposing part of silver dibutyldithiocarbamate in the mixed solution B to generate silver sulfide clusters; the activity of the silver sulfide cluster is closely related to the size, the silver sulfide cluster is used as a seed to induce growth of silver-indium-zinc-sulfur, meanwhile, silver sulfide is converted into silver-indium-sulfur, finally, the silver-indium-sulfur and silver-indium-zinc-sulfur composite nano material is obtained, the band gap is 2.0-2.8 eV, the luminous efficiency is 52% or above, and the luminous efficiency can still be kept at 78% or above after five months. The preparation process disclosed by the invention is low in raw material cost and good in process controllability.

The invention discloses a methylamine formamidino perovskite single crystal, a preparation method thereof and an X-ray detector, and belongs to the technical field of perovskite single crystal X-ray detectors. Methyl iodide amine, formamidino hydriodate and lead iodide are used as raw materials, anhydrous acetic acid is used as an additive, growth is carried out in a solvent through a seed crystal method, and the methylamine formamidino perovskite single crystal is obtained. Anhydrous acetic acid and formamidine generate hydrogen-bond interaction, formamidine is pulled to enter crystal lattices, so that phase separation is eliminated, acetate and Pb coordinate to delay formation of a lead-iodine framework, the speed of methylamine and formamidine entering the crystal lattices is balanced, meanwhile, the stability of a methylamine formamidine perovskite precursor solution is improved, stable growth of methylamine formamidine perovskite single crystals is achieved, and the methylamine formamidine perovskite single crystals are obtained. The single crystal has the advantages of high crystallinity, low defect density, large size and favorable X-ray response performance. The methylamine formamidine perovskite single crystal is high in controllability in the growth process, and the preparation method is high in operability, simple and easy to implement, short in preparation period, low in equipment requirement and low in cost.

This invention provides a wide-bandgap perovskite thin film, a perovskite tandem solar cell, and a method for preparing the same, relating to the field of photovoltaic technology. The method for preparing the perovskite thin film includes: adding a perovskite structural material and an organic additive to an organic solvent to obtain a perovskite precursor solution; spin-coating the perovskite precursor solution onto a substrate; and annealing the substrate to obtain the perovskite thin film. The organic additive includes a material containing a thiophene dioxide framework. The organic additive used in this invention can effectively regulate the crystallization rate of mixed halides, delay crystallization, enhance the uniform distribution of the mixed halide phase, reduce the defect density in the wide-bandgap perovskite thin film, and significantly improve the power conversion efficiency and stability of the solar cell, thereby obtaining a high-performance tandem solar cell.

The application discloses an oxide semiconductor thin film transistor and a preparation method thereof. The oxide semiconductor thin film transistor comprises a substrate, a gate electrode on the substrate, a gate dielectric layer on the gate electrode, an effective induction layer, the effective induction layer comprising a channel layer a, a channel layer b and a channel particle layer arranged from bottom to top, the channel layer a being on the gate dielectric layer, an induction layer on the channel particle layer, and a source electrode and a drain electrode arranged on the gate dielectric layer and the effective induction layer. The oxide semiconductor thin film transistor has high mobility and stability.

The invention relates to an application of a pyrimidine-based additive in a perovskite solar cell. A pyrimidine derivative with moderate Lewis alkalinity is selected as the additive and forms a moderate and stable coordination intermediate with a lead iodide precursor, so that nucleation of alpha-phase formamidine lead iodide can be accelerated and defect generation can be inhibited; the method is suitable for planar formal and trans-structure devices, the photoelectric conversion efficiency of 25% or above is achieved in the formal structure and the trans-structure, and excellent stability is kept under the long-time operation and storage conditions. The invention provides an additive design principle based on pyrimidine molecules, and provides a theoretical basis and a technical path for development of high-performance and long-life perovskite photovoltaic devices.

The application discloses a kind of perovskite laminated solar cell and preparation method thereof, photovoltaic module and photovoltaic device, belong to solar cell technical field.The perovskite laminated solar cell from light-receiving front to light-receiving back successively includes substrate, bottom electrode, first hole transport layer, wide band gap perovskite layer, first electron transport layer, barrier layer, intermediate interconnection layer, narrow band gap perovskite layer, second electron transport layer, hole blocking layer, top electrode;The intermediate interconnection layer includes first sublayer, self-assembled monolayer and second sublayer, first sublayer faces first electron transport layer, second sublayer faces narrow band gap perovskite layer, and self-assembled monolayer is located between first sublayer and second sublayer.The application can inhibit interface scattering and reduce wide-angle reflection loss under oblique incidence, while maintaining excellent electrical transmission to promote carrier transfer and recombination, significantly improve the overall photovoltaic performance of device.

This invention belongs to the field of solar cell technology, specifically relating to a top-down defect passivation perovskite solar cell. It includes, from bottom to top, a transparent conductive substrate, an electron transport layer, a first passivator layer, a perovskite layer, a second passivator layer, a hole transport layer, and a back electrode. The perovskite layer has an inverse opal structure, comprising perovskite and spherical pores. Several layers of spherical pores are arranged sequentially from top to bottom within the perovskite layer, with several pores per layer. This invention utilizes the three-dimensional continuous through-holes of the inverse opal perovskite structure to promote the penetration of the passivator to the buried interface, thereby achieving overall defect passivation of the perovskite bulk phase and the perovskite / carrier transport layer interface. Furthermore, the slow-light effect of the inverse opal structure helps to prolong the interaction time between incident light and the perovskite, enhancing light absorption performance. Ultimately, a perovskite solar cell with high photoelectric conversion efficiency and good long-term stability is obtained.

This invention relates to the field of nanomaterial preparation and polycrystalline thin film preparation technology, specifically providing a method for controlling the orientation of polycrystalline thin films using antisolvents. This aims to solve the problems of existing preparation methods, such as cumbersome implementation, incompatibility with industrial production, and potential negative impacts on the integrity of the polycrystalline thin film. To this end, the method for controlling the orientation of polycrystalline thin films using antisolvents includes: coating a pre-prepared precursor solution onto a substrate; coating an antisolvent corresponding to a specific target orientation onto the substrate containing the precursor solution; and subjecting the coated substrate containing the precursor solution and antisolvent to low-temperature annealing to obtain a polycrystalline thin film with the specific target orientation. The annealing time is negatively correlated with the annealing temperature. The polycrystalline thin films prepared by the method of this invention exhibit high orientation consistency, low defect density, high carrier mobility, and a more compact and flat film morphology.

The invention provides a perovskite thin film and a preparation method and application thereof. The preparation method comprises the following steps: providing a perovskite precursor solution; coating the perovskite precursor solution on a substrate to form a perovskite wet film; carrying out annealing treatment on the perovskite wet film to obtain a perovskite thin film; in the annealing treatment process, auxiliary airflow and an auxiliary electric field are applied at the same time, the flowing direction of the auxiliary airflow is parallel to the plane where the perovskite wet film is located, and the direction of the auxiliary electric field is perpendicular to the plane where the perovskite wet film is located. By introducing a multi-physical field coupling environment formed by the auxiliary airflow and the auxiliary electric field, the dynamic effect of the airflow and the electrostatic guiding effect of the electric field are synchronously exerted in the annealing process, and the nucleation and growth processes of the perovskite thin film are collaboratively optimized; according to the coupling technology, the crystallization orientation degree and the grain orderliness of the perovskite film can be improved, disordered migration of ions is inhibited, the defect density of the film is reduced, and the uniformity and the stability of the perovskite film are improved.

This invention belongs to the field of optoelectronic technology, specifically relating to a method for fabricating a controllable crystallization micron-scale perovskite light-emitting device based on solution pretreatment. The method includes the following steps: Step 1: Obtaining a patterned microporous substrate; Step 2: Pre-wetting and seed layer construction; Step 3: Deposition of the main perovskite layer; Step 4: Slow-release controllable crystallization; The spin-coated wet film is placed in a vapor atmosphere of a good solvent for treatment, followed by thermal annealing to form a perovskite thin film within the patterned micropores; Step 5: Fabrication of a controllable crystallization micron-scale perovskite light-emitting device based on solution pretreatment. This invention, using pre-wetting, seed guidance, slow-release crystallization, and vapor annealing on a patterned microporous substrate, achieves precise control over the entire process of film nucleation and growth kinetics within the confined space of the micropores, thereby achieving high-quality, uniform fabrication of perovskite thin films within micron-scale micropores, and ultimately obtaining a high-performance, highly uniform microarray perovskite light-emitting device.

This invention discloses a method for preparing halide perovskite thin films and their applications. The preparation method includes the following steps: S1, providing a substrate; S2, mixing a precursor salt with a lactone solvent to form a precursor mixture; S3, depositing the obtained precursor solution onto the surface of the substrate and annealing it to form a perovskite thin film. This invention, by introducing a monocyclic lactone, overcomes the limitations of the traditional DMF / DMSO solvent system, significantly expanding the material compatibility range of solution processing, enabling stable film formation over a wider range of concentrations and temperatures. Utilizing the unique coordination ability and volatility characteristics of this type of lactone, crystallization kinetics can be effectively controlled, promoting more uniform and dense perovskite grain growth, significantly reducing the defect density inside the film, thereby obtaining a film with high crystallinity.

The application relates to the technical field of semiconductors, in particular to a single crystal growth method and a preparation method of a single crystal and an epitaxial film and an epitaxial wafer. The 4H-SiC single crystal growth method comprises the following steps: providing a 4H-SiC seed crystal, slanting cutting the 4H-SiC seed crystal along a crystal direction, the 4H-SiC seed crystal has a step extending along a direction, a step edge of the 4H-SiC seed crystal exposes a polar site, a polar step edge is formed, the polar step edge is more prone to adsorbing carbon atoms and silicon atoms in the environment, the 4H-SiC crystal maintains a stable and ordered step flow growth mode along a specific direction, the generation of polymorphism can be effectively inhibited, and the density of polymorphism-induced dislocations is reduced.

The invention discloses a preparation method of a ZnO window layer film with Mo as a buffer layer, and belongs to the technical field of film preparation. The method sequentially comprises the steps of substrate pretreatment, Mo buffer layer magnetron sputtering deposition, ZnO window layer radio frequency magnetron sputtering deposition and annealing post-treatment. Through precise regulation and control of process parameters, lattice transition matching is realized by means of characteristics of Mo and ZnO. The method effectively solves the problems of weak binding force between the ZnO film and the substrate, poor crystallization quality, high defect density, high energy consumption and the like in the prior art, is high in process compatibility and controllable in parameter, is suitable for large-scale preparation of the high-performance ZnO film, and can be widely applied to the photoelectron fields of solar cells, display devices and the like.

The invention discloses a process method and process equipment of a semiconductor device. The process method comprises the following steps: acquiring a substrate with an original thin film; introducing a first gas into the process cavity; high-temperature plasma treatment is conducted on the first gas, so that the first gas is ionized and excited to release ultraviolet photons, the ultraviolet photons penetrate through the surface of the original thin film, impurity atoms in the original thin film are removed, and the energy of the ultraviolet photons generated by the first gas is larger than the chemical bond energy of the impurity atoms. By executing the steps, the defect density in the tunneling layer thin film can be reduced, so that the overall quality of the thin film is improved, the occurrence of leakage current of the memory can be effectively reduced, the service life of the memory is prolonged, the breakdown voltage of the memory can be improved, and the reliability of the memory is improved.

The application relates to the technical field of semiconductor photoelectric devices and thin film manufacturing, and particularly discloses a preparation method of a light detector based on a sputtering hybrid semiconductor thin film. The prepared light detector comprises, from bottom to top, a transparent conductive substrate, a bottom charge transport layer, a hybrid semiconductor light absorption layer, a top charge transport layer and a metal electrode. The hybrid semiconductor light absorption layer is prepared by using a magnetron sputtering process based on target self-heating. The thermal electron emission effect of the target self-heating is used to excite high-density plasma at a low working voltage, to rapidly and lowly damage the target for sputtering, and to form a dense and pure-phase hybrid semiconductor thin film. The application uses a multi-dimensional method of adjusting the cathode surface magnetic flux, adjusting the working voltage and target self-heating to improve the plasma density in the chamber. While realizing high-speed deposition of 30-500 nm / min, the hybrid semiconductor thin film defect density is reduced and the photoelectric performance of the light absorption layer is improved.

The invention discloses a GaN-based HEMT device and a preparation method thereof. The preparation method comprises the following steps: providing a growth substrate; preparing a two-dimensional insulating material layer on the growth substrate; preparing a GaN-based epitaxial structure on the two-dimensional insulating material layer based on Van der Waals epitaxial growth, wherein the GaN-based epitaxial structure comprises a channel layer and a barrier layer which are sequentially stacked on the two-dimensional insulating material layer; providing a heat dissipation substrate, and bonding the heat dissipation substrate on the surface of one side, far away from the growth substrate, of the GaN-based epitaxial structure; and stripping the growth substrate. According to the method, the two-dimensional insulating material layer is firstly prepared on the growth substrate, and then the epitaxial structure is prepared on the two-dimensional insulating material layer, so that the problem of surface state induced electric leakage of the growth substrate is conveniently solved, and complete stripping and cyclic utilization of the expensive growth substrate are realized by utilizing the characteristic that the two-dimensional insulating material layer is easy to strip; and the performance of the GaN-based HEMT device is further improved while the manufacturing cost is greatly reduced.

The invention discloses a surface treatment method of a single crystal perovskite thin film, a perovskite cell and a preparation method thereof. The preparation method of the perovskite cell comprises the following steps: S1, preparing a bottom electrode and a hole transport layer on a substrate in sequence; s2, growing an initial single crystal perovskite thin film on the hole transport layer; s3, a chemical polishing agent solution is applied to the surface of the single-crystal perovskite thin film for chemical polishing, the chemical polishing agent solution does not contain grinding particles, and polishing is stopped after chemical polishing is conducted till the surface roughness RMS of the single-crystal perovskite thin film is smaller than 5 nm; s4, a passivating agent solution is applied to the surface of the single crystal perovskite thin film after chemical polishing for post-passivation; and S5, sequentially preparing an electron transport layer and a back electrode on the single crystal perovskite thin film after post-passivation to obtain the perovskite cell. According to the invention, the surface of the single crystal perovskite thin film is optimized, and the photoelectric conversion efficiency and stability of the perovskite solar cell are improved at the same time.

The invention relates to the technical field of solar cells, in particular to a five-junction solar cell based on bonding of a composite substrate and a wafer and a preparation method of the five-junction solar cell, and the preparation method comprises the following steps: 1) preparing a silicon-based InP film; 2) epitaxially growing a forward two-junction solar cell on the silicon-based InP thin film through MOCVD (Metal Organic Chemical Vapor Deposition); 3) epitaxially growing a reverse triple-junction solar cell on the GaAs substrate through MOCVD (Metal Organic Chemical Vapor Deposition); 4) heterogeneously integrating two sub-cells at the bottom of the silicon-based InP thin film and three sub-cells at the top of the gallium arsenide substrate through a wafer bonding technology; the three-junction solar cell and the preparation method thereof have the advantages that the performance is excellent, the collection efficiency of photon-generated carriers is effectively improved, the photoelectric conversion efficiency of the three-junction solar cell is improved, the application prospect is wide, and the like.

The invention discloses a strain slow-release Ge / Si / SiGe heterostructure. The strain slow-release Ge / Si / SiGe heterostructure sequentially comprises a Ge substrate, a Si buffer layer and a SiGe epitaxial layer from bottom to top, the thickness of the Si buffer layer is 5-12 nm; and the thickness of the SiGe epitaxial layer is 180 to 200 nm. The invention also discloses a growth method of the strain slow-release Ge / Si / SiGe heterostructure. The growth method specifically comprises the following steps: carrying out surface treatment and activation on the Ge substrate; epitaxially growing a Si buffer layer on the Ge substrate by adopting LPCVD (Low Pressure Chemical Vapor Deposition); and growing a SiGe epitaxial layer on the Si buffer layer by adopting an LPCVD (Low Pressure Chemical Vapor Deposition) method, and cooling. By constructing the strain slow-release Ge / Si / SiGe heterostructure, effective regulation and control of a Ge / Si interface mismatch strain release path are realized, dislocation is released in the Si buffer layer in a preposed manner and is terminated at the Si / SiGe interface, and thus the defect density in the SiGe epitaxial layer is remarkably reduced.

The invention belongs to the technical field of flow batteries, and discloses a V2C nanosheet composite electrode as well as a preparation method and application thereof. The preparation method comprises the following steps: etching MAX ceramic powder by using a mild acidic solution with the pH value of 4 and NaF to obtain a V2C material; carrying out silanization coupling agent treatment, inert / reducing atmosphere ice bath ultrasonic treatment and centrifugation to prepare a V2C-Si-NH2 nanosheet; a graphene electrode is soaked in the nanosheet suspension, an amide coupling agent is added for a water bath reaction, and the binder-free composite electrode is obtained. The electrode is combined through a C-C (O) NH-Si-V2C covalent bond, and the V2C nanosheet is low in defect and uniform in dispersion and has high conductivity and catalytic property. The method can be applied to all-vanadium, zinc-iron and other flow batteries, can improve the coulombic efficiency and energy efficiency of the batteries, and is suitable for industrialization of the flow batteries.