17 results about "Piezoelectric polarization" patented technology

This invention discloses an interlayer confined piezoelectric composite film of graphene oxide, its electric field-driven preparation method, and its application. The preparation method includes: preparing a graphene oxide dispersion using the Hummers method and filtering it to form a graphene oxide film; placing the graphene oxide film in an electric-driven device, introducing different precursor solutions on both sides of the film, and driving the precursor components to migrate into the interlayer confined space of the graphene oxide under the action of an applied electric field; under the synergistic effect of electric field driving and interlayer confinement, the precursors entering the interlayer react and crystallize in situ to form a piezoelectric functional phase. The prepared composite film can generate piezoelectric polarization under mechanical stimulation conditions and can be used for ion selective adsorption / separation, especially suitable for the selective adsorption / separation of uranium and vanadium ions in high-salt water systems. This invention achieves a synergistic improvement in interfacial charge regulation and ion selectivity regulation by constructing a piezoelectric functional phase in situ within the interlayer confined space of graphene oxide.

The invention relates to the technical field of electrocatalytic materials, in particular to a SnSe piezoelectric catalyst and a preparation method and application thereof. The preparation method comprises the following steps: dispersing selenium powder in deionized water, adding NaBH4 powder to obtain a selenium source precursor solution, dispersing sodium ascorbate in deionized water, adding anhydrous SnCl2 powder to obtain a tin source precursor solution, and adding the selenium source precursor solution into the tin source precursor solution to obtain a mixed solution; the pH value of the mixed solution is adjusted to 2-7, then the mixed solution is subjected to a hydrothermal reaction, and the SnSe piezoelectric catalyst is obtained through filtering and drying in sequence. In a one-step hydrothermal system, through coordinated regulation and control of pH and hydrothermal temperature, coordinated regulation of the SnSe material in the aspects of nucleation, growth, valence evolution and defect structure is realized, a novel piezoelectric catalytic material with a mixed valence structure and nanorod morphology is successfully constructed, the piezoelectric polarization capability, the carrier separation efficiency and the ROS generation capability of the material are remarkably enhanced, and the preparation method is simple and easy to implement. And excellent organic pollutant degradation performance is obtained.

This invention discloses a light-emitting diode (LED) epitaxial wafer and its fabrication method. The LED epitaxial wafer includes a substrate and, sequentially stacked on the substrate, a buffer layer, an undoped GaN layer, an N-type GaN layer, a composite insertion layer, a multiple quantum well layer, an electron blocking layer, and a P-type GaN layer. The composite insertion layer includes, sequentially stacked on the N-type GaN layer, a BN layer, a BInN layer, and a weakly P-type nitride layer. The LED fabricated by this invention can improve the crystal quality of the multiple quantum well layer and alleviate the piezoelectric polarization of the multiple quantum well layer, thereby improving the luminous efficiency of the LED epitaxial wafer.

This invention proposes a semiconductor laser device with a spin-polarized sublayer, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer. This invention establishes a multi-layered spin-polarized sublayer structure between the upper confinement layer and the upper waveguide layer in the semiconductor laser device, and defines the electron mobility distribution and piezoelectric polarization coefficient distribution characteristics of each spin-polarized sublayer. The specific electron mobility distribution and piezoelectric polarization coefficient distribution of the spin-polarized sublayer form an asymmetric discrete potential barrier, modulating the polarization of the lattice distortion structure, increasing the net accumulation of charge dipole momentum, controlling the piezoelectric polarization effect of the active layer, suppressing the quantum confinement Stark effect, reducing the band tilt of the active layer, reducing the hole injection band order, increasing the overlap probability of electron-hole wave functions, and improving the internal quantum efficiency.

The present application relates to a kind of barrier layer structures with asymmetric insertion layer, including barrier layer, barrier layer is used to form source, gate and drain, insertion layer is embedded in barrier layer inside, insertion layer forms first insertion section between source to gate, forms second insertion section between gate to drain, the thickness of first insertion section is less than the thickness of second insertion section;A kind of power device, including barrier layer structure with asymmetric insertion layer.In the present application, the spontaneous polarization, piezoelectric polarization effect of asymmetric insertion layer is much stronger than barrier layer, the insertion layer of gate, drain side is thicker, resulting in local barrier being higher, electric field peak spontaneously migrates from gate edge to drain side and gradually reduces, the distribution of peak electric field is optimized, and the overall performance of device is improved;The breakdown voltage of the present application is effectively improved, peak electric field is significantly reduced, Ron is not degraded basically, current collapse effect is significantly inhibited, meet the design requirements of high-voltage GaN HEMT.

The application provides a surface-emitting gallium nitride VCSEL laser chip and an epitaxial defect suppression preparation method thereof, relates to the technical field of laser chips, and comprises a substrate, a low-temperature nucleation layer, a high-temperature recovery layer, a stress regulation type nano mask composite defect blocking layer, an n-type nitride DBR reflector, an active region and a polarization enhancement type tunnel junction and the like. The defect blocking layer adopts an in-situ silicon nitride nano porous mask layer in cooperation with an aluminum gallium nitride / gallium nitride stress compensation superlattice layer, penetrative dislocations are annihilated through pulse type lateral epitaxial overgrowth, the n-type nitride DBR reflector adopts an AlInN / GaN lattice matching material system combined with a hydrogen etching interruption modification technology, zero crack and high reflectivity thick film growth are realized, the top uses a polarization enhancement type tunnel junction to replace ITO, the hole tunneling probability is enhanced by using the piezoelectric polarization in InGaN, low working voltage, absorption loss-free high-efficiency current injection are realized, the dislocation density and the device voltage are significantly reduced, and the epitaxial wafer yield and the photoelectric conversion efficiency are improved.

The application discloses a gallium nitride-based bipolar junction transistor and a preparation method thereof, and relates to the technical field of semiconductors; a two-dimensional electron gas layer is generated on the side close to a GaN channel layer at the interface between an AlGaN barrier layer and the GaN channel layer through piezoelectric polarization and spontaneous polarization effects; a groove for depositing and growing a P-type semiconductor layer is formed by etching from the middle of the top surface of an insulating layer to the bottom surface of the GaN channel layer; two grooves for depositing and growing an emitter and a collector are formed by etching from the top surface of an emitter insulating layer away from the end of the P-type semiconductor layer and the top surface of a collector insulating layer away from the end of the P-type semiconductor layer to the top surface of an emitter AlGaN barrier layer; a base is deposited and grown on the top surface of the P-type semiconductor layer; and the application can greatly improve the mobility of electrons in the emitter and the collector, and improve the large-current output capability, power density and high-frequency application capability of the device.

The invention provides a p-channel gallium nitride transistor structure and a preparation method thereof. The p-channel gallium nitride transistor structure comprises a substrate layer, a gallium nitride layer, an aluminum-gallium-nitrogen layer, a p-type indium-gallium-nitrogen channel layer and a p-type indium-gallium-nitrogen layer which are sequentially stacked, a gate groove of which the bottom is positioned on the surface of the p-type indium gallium nitrogen channel layer is formed in the middle of the p-type indium gallium nitrogen layer; a source electrode and a drain electrode are respectively arranged on the surface, far away from the p-type indium gallium nitrogen channel layer, of the p-type indium gallium nitrogen layer on the two sides of the gate groove; and an aluminum oxide layer and a gate metal layer are laminated on the gate groove. According to the heterojunction formed by the invention, due to strong piezoelectric polarization, higher on-state current density can be obtained under the condition of ensuring an E-mode working state, effective E-mode operation is realized, an effective way is provided for a GaN CL circuit, the main challenges of E-mode GaN p-FETs (that is, the p-FET is relatively low in current density and is difficult to match with a large-current n-FET) are solved, and the performance of the GaN CL circuit is promoted.

This invention proposes a GaN-based compound semiconductor laser device, comprising, from bottom to top, a substrate, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer. An electron spin state modulation layer is disposed between the lower confinement layer and the lower waveguide layer. The invention designs the piezoelectric polarization coefficient distributions of the first and second electron spin state modulation layers within the electron spin state modulation layer, as well as the relationship between the piezoelectric polarization coefficients of the lower confinement layer, the lower waveguide layer, the first electron spin state modulation layer, and the second electron spin state modulation layer. This invention can improve the performance of semiconductor laser devices.

The invention discloses a preparation method of a depletion mode and enhancement mode ScAlN / GaN-based HEMT (High Electron Mobility Transistor) with adjusted element components, and belongs to the field of semiconductor devices. The Sc component is utilized to regulate and control spontaneous polarization and piezoelectric polarization of the ScAlN, adjustment of two-dimensional carriers of the ScAlN / GaN heterojunction is achieved, and therefore depletion mode and enhancement mode GaN-based HEMT devices are achieved under the same technical route. According to the invention, only the Sc component of the ScAlN barrier layer needs to be adjusted, the depletion mode HEMT device and the enhancement mode HEMT device with electron or hole conduction can be selectively prepared, and the production technology is simple. The depletion type ScAlN / GaN-based HEMT device provided by the invention can realize higher two-dimensional carrier concentration, and can be applied to the field of high-power circuits. According to the enhanced ScAlN / GaN-based HEMT, the technological process is greatly simplified, the device preparation difficulty is low, and the reliability is better; meanwhile, due to the fact that the process steps are few, damage to the device structure in different stages is smaller, and the device yield is effectively improved.

The application provides a semiconductor laser, which comprises, from bottom to top, a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer, an electron blocking layer and an upper limiting layer; the active layer is a periodic structure composed of a well layer and a barrier layer; the refractive index coefficient of the well layer is greater than that of the barrier layer; the dielectric constant of the well layer is greater than that of the barrier layer; and the piezoelectric polarization coefficient of the well layer is greater than that of the barrier layer. The application differentiates the refractive index coefficient, the dielectric constant and the piezoelectric polarization coefficient of the well layer and the barrier layer in the active layer, thereby improving the photon degeneracy, making the stimulated radiation of the laser greater than the spontaneous radiation, improving the coherence, the limiting factor and the slope efficiency of the transverse mode, reducing the number of longitudinal modes and the mode variation, improving the time coherence of the longitudinal mode and the far field FFP image quality, the beam quality factor and the focusing spot resolution.

The invention relates to the technical field of semiconductor light-emitting diodes, and discloses a double-sided flip chip LED light source and a manufacturing method thereof, and the manufacturing method comprises the steps: arranging P electrodes and a rigid support array which is higher than the P electrodes on the surface of a P-type layer of an LED epitaxial wafer at intervals; bonding the side of the P-type layer with the substrate, removing the growth substrate through laser lift-off, and generating a strain-induced sunken region on the surface of the N-type layer; a piezoelectric polarization field generated by the supporting array is used for guiding functional molecules to directionally adsorb on the periphery of the strain induction sunken area, and a wettability modification layer is constructed; coating a photosensitive medium layer, jointly constructing a thickness step interface by the wettability modification layer and the strain induction sunken area, and removing the photosensitive medium and preparing the N electrode according to the interface. Through physical morphology and chemical surface energy dual mask boundary control, the self-alignment opening sharpness is improved, the three-dimensional space self-stabilization of the ultrathin epitaxial structure is realized, and the self-alignment performance of the N electrode is improved. And the carrier transport path is shortened.

This invention relates to the field of semiconductor laser technology, specifically to an epitaxial structure of a GaN-based blue laser and its fabrication method. The structure includes a substrate on which an N-type GaN layer, an N-type lower confinement layer, an N-type lower waveguide layer, an active region, an upper waveguide layer, a U-type capping layer, a P-type electron blocking layer, a P-type upper confinement layer, and a P-type contact layer are sequentially stacked. The P-type electron blocking layer comprises a sequentially stacked AlN sublayer and a P-type InAlGaN sublayer. The P-type electron blocking layer of this invention utilizes the piezoelectric polarization and spontaneous polarization of the P-type InAlGaN sublayer to induce a large band bend at the heterojunction, placing the P-type dopant acceptor energy level below the Fermi level, thereby increasing the ionization rate of the P-type dopant acceptor at the cross-section and thus increasing the hole concentration. Furthermore, the use of a high-Al composition AlN sublayer near the active region can raise the energy band, confine electron overflow in the active region, and reduce non-radiative recombination of electrons and holes in the non-recombination region, thereby improving the luminous efficiency of the device.

This invention discloses a method and apparatus for activating uranium ore in argillaceous sandstone, relating to the field of uranium resource development technology. It comprises BaTiO3 nanowires and carbon nitride, with the BaTiO3 nanowires and carbon nitride composite forming a piezoelectric catalytic heterostructure with interfacial coupling effects. Under mechanical stress, the BaTiO3 nanowires generate a piezoelectric polarization field, promoting the effective separation of electron-hole pairs; carbon nitride synergistically enhances the generation and migration efficiency of charge carriers with the BaTiO3 nanowires. This composite catalyst can activate hydrogen peroxide in situ using the mechanical energy provided by stirring without the need for an external power source or strong radiation, maintaining high catalytic activity even in complex slurry environments. The apparatus provided by this invention significantly improves the piezoelectric catalytic efficiency of the composite catalyst through the deep synergy of multi-stage deformation and three-dimensional turbulence, making it suitable for the green and efficient leaching of uranium ore in argillaceous sandstone with low permeability and high clay content.

A lower waveguide layer comprises a first lower waveguide layer and a second lower waveguide layer, the second lower waveguide layer is a gradient polarization lower waveguide layer, and an upper waveguide layer is a gradient polarization upper waveguide layer. A fitting curve of In ion strength distribution or In atom concentration distribution, a fitting curve of piezoelectric polarization coefficients and a fitting curve of spontaneous polarization coefficients of the waveguide layer under gradient polarization all meet ExpDec1 first-order exponential decay function distribution, wherein the fitting curve of In ion strength distribution or In atom concentration distribution, the fitting curve of piezoelectric polarization coefficients and the fitting curve of spontaneous polarization coefficients are tested by an SIMS. The fitting curve of In ion strength distribution or In atom concentration distribution, the fitting curve of piezoelectric polarization coefficient and the fitting curve of spontaneous polarization coefficient of the gradient polarization upper waveguide layer in SIMS test all meet ExpAssoc double-exponential correlation growth function distribution, so that the performance of the gallium nitride-based semiconductor laser is effectively improved.

The application discloses a nitride semiconductor epitaxial structure for improving blue-green dual-wavelength light-emitting intensity and a growth method thereof. The epitaxial structure comprises, in sequence, a buffer layer, an undoped GaN layer, an undoped GaN layer, an N-type GaN layer, a stress release layer, a stress release layer, a green light multi-quantum well structure, a V-type defect filling layer, a low-temperature open Pits layer, a defect blocking layer, a blue light multi-quantum well structure, an electron buffer layer, an electron blocking layer, a P-type GaN layer, an InGaN contact transition layer and a P-type contact layer. The green light multi-quantum well structure adopts a wide-well narrow-barrier design to relieve lattice strain and piezoelectric polarization effect. Three layers of defect regulation structures are arranged between the green light region and the blue light region, penetration dislocations are inhibited from extending to the blue light region through stress induction and dislocation conversion, and the crystal quality is improved. The growth method controls the epitaxy of each functional layer in different temperature zones and V / III ratio conditions in stages, and realizes the construction of a high-quality multi-quantum well integrated structure.

The invention belongs to the technical field of preparation of piezoelectric catalyst materials, and particularly relates to an Hg3O2SO4 piezoelectric catalyst and a preparation method thereof. The preparation method comprises the following steps: dissolving mercury, a sulfur source and an acid source in deionized water to form a precursor solution, then carrying out hydrothermal reaction, cleaning and drying, then mixing the precursor solution with deionized water, then carrying out ball milling, and washing and drying the ball-milled slurry to obtain the Hg3O2SO4 piezoelectric catalyst. The Hg3O2SO4 piezoelectric catalyst prepared by the preparation method disclosed by the invention has an enhanced piezoelectric polarization characteristic, and has a very strong capability of separating hydrogen from water under a dark condition.