179 results about "Residual polarization" patented technology

A memory wherein any “disturb effect” can be suppressed in which data in unselected memory cells are lost. This memory has a memory cell array(1) including bit lines, word lines, which are disposed to intersect the bit lines, and memory cells(12) each connected between bit and word lines. In this memory, an access operation, which includes at least one of read, rewrite and write operations, is made to a selected memory cell(12). During this access operation, it is performed to apply to the memory cell(12) a first voltage pulse, which provides an electrical field in a first direction so as to invert a stored data, and a second voltage pulse, which provides as electrical field in the opposite direction to the first one so as not to invert the stored data. In addition, a recovery operation for recovering a residual polarization amount is made to the memory cell(12).

The polarity inversion cycle of a voltage applied to a liquid crystal layer is set to at least 2-frame cycle, or more preferably to as long as about 10 sec. Accordingly, a flicker that could not have been prevented at a polarity inversion cycle of about one frame can be prevented, and a longer inversion cycle can reduce power consumption. A material low in ion reactivity and small in residual polarization is used as a liquid crystal material or an orientation film material, thereby preventing the occurrence of a residual DC component in a liquid crystal layer and the deterioration of display quality despite a longer polarity inversion cycle. In the case of an LCD provided with a minimal transmittance with respect to an applied voltage, black can be accurately displayed by, for example, regulating a common electrode potential so that an applied voltage at which the transmittance of a liquid crystal shows a minimum value during an anodic application period is equal to that during a cathodic application period.

The invention belongs to the field of micro-nano semiconductor optoelectronic devices, and particularly relates to a phototransistor based on a ferroelectric gate dielectric and a thin layer MoS2 channel and a preparation method thereof. The phototransistor comprises a source electrode, a leakage electrode, a channel, a gate electrode, a gate dielectric, a metal pad, and a substrate. The source electrode and the leakage electrode are graphene, the channel is thin layer MoS2, and the gate dielectric is a PZT ferroelectric membrane. Compared with existing similar phototransistor, the phototransistor has the following advantages that first, a high dielectric coefficienet of the PZT ferroelectric membrane helps improve the adjustment performance of the gate electrode for a channel carrier; second, the PZT ferroelectric membrane can adjust the channel carrier with surplus polarity field strength, so that the power consumption of the device is lowered; third, compared with organic ferroelectric material P (VDF-TrFE), the PZT ferroelectric membrane has the advantages of high surplus polarity, low coercive field strength, stable property and compatibility with microelectronic process; and fourth, as the source electrode and leakage electrode, the graphene can improve the signal light transmittance, and improve the light response degree and gain of the device.

The invention provides a method for preparing a piezoelectric-ferroelectric thin film, relating to the technical field of preparation of lead zirconate titanate ceramics and being realized by the steps of preparing a precursor solution, utilizing a PLD method to prepare a substrate and adopting a Sol-Gel method to prepare the piezoelectric-ferroelectric thin film on a PZT crystal seed layer. The invention utilizes a method combing PLD and Sol-Gel to prepare a PZT thick film, thus having strong applicability to different substrates; and the prepared PZT thick film has the obvious advantages of high preferred orientation, even crystal size and compact structure, and can be used for preparing a lead zirconate titanate thin film with the thickness of 3-6 microns, the residual polarization value Pr of 25-45 mu C / cm<2> and the coercive field Ec of 40-65 kV / cm. At the same time, the method in the invention has relative low cost, strong controllability of programs and high industrialized application value.

A polyamide obtained by polycondensation of a diamine component containing at least 50 mol % of 2-methyl-1, 5-pentanediamine and a dicarboxylic acid component containing at least 50 mol % of azelaic acid, comprising the following properties of (1) to (4), (1) when a stretched film is polarized in an electric field of 200 MV / m, a remanent polarization is at least 30 mC / m<2>, (2) the relative viscosity of a 1 g / dl solution of the polyamide in 96% concentrated sulfuric acid at 25 ° C. is 1.3 to 5.0, (3) the glass transition temperature is 80° C. or less and a calorific value at a cooling crystallization exotherm peak is 5 J / g or less, and (4) it is soluble in an amount of at least 5 mass % at 25 ° C. in at least one selected from methanol, ethanol and 2-propanol, and a resin composition containing the above polyamide and an electrically conductive material.

The invention relates to a BiFeO3-base sandwich structure film used for a ferroelectric memory and a process for preparation, belonging to the technical field of microelectronic new materials, wherein the upper surface component and the lower surface component of the BiFeO3-base sandwich structure film both are BiFe1-xHxO3, H is doped high valence ion with quadravalence or over quadravalence, the component of the intermediate layer is BiFe1-xLxO3, L is doped high valence ion with trivalence or below trivalence. The process for preparation comprises adopting the chemical solution method combined with the annealing technology in layer by layer, and preparing through depositing precursor solution in the surface layers of different materials in the spin-coating method. The invention greatly reduces the drain current of the film through adopting a special sandwich structure, effectively reduces coercive field, significantly increases the charge retention, obtains the ferroelectric film with low drain current, large residual polarization, low coercive field and excellent charge retention under the annealing temperature of 500 DEG C-600 DEG C, and has great practicable prospects in further ferroelectric memories.

This invention discloses a method for preparing highly (111)-oriented PZT thin film. The method can solve the problems of complex process and low repeatability faced by sol-gel method. The method comprises: preparing PZT sol, depositing PZT thin film, pre-crystallizing PZT thin film, and crystallizing PZT thin film. The method is simple. The obtained PZT thin film has compact and smooth surface, uniform thickness, uniform grain sizes, high residual polarization value (43-60 muC / cm2), low coercive field (60-75 kV / cm), and high saturated polarization value.

The invention discloses a method for preparing a bismuth ferric film material. The method adopts a pulsed laser deposition technology; a bismuth ferric film is deposited on a silicon substrate coveredby an electrode; and the bismuth ferric film with high remnant polarization is obtained by adjusting process parameter in deposition process and in-situ annealing. The method has the advantages thatthe single-crystal silicon is taken as the substrate material, the remnant polarization of the obtained bismuth ferric film is higher than that of the traditional ferroelectric film, and the bismuth ferric film is an ideal material for silicon-based ferroelectric components such as a ferroelectric memory and the like.

The chemical formula Bi4-xNdxTi3O12 relates to the 20-500nm Nd-doped bismuth titanate ferro-electricity thin film, wherein, x denotes the mole percent of Nd in total mole number of Nd and Bi, while the surplus content of Bi element takes up of 5-20% as the total mole number of Bi, Nd and Ti. The preparation method comprises preparing predecessor sol and preparing the thin film, respectively. This product has super anti-fatigue property, high Pr value, lower Vc value, and compatible with CMOS technology.

The invention provides a multiferroic Bi1-xRExFe0.97-yMn0.03TMyO3 / CoFe2O4 composite film and a preparation method thereof. The composite film comprises a Bi1-xRExFe0.97-yMn0.03TMyO3 crystalline state film and a CoFe2O4 crystalline state film. The preparation method comprises the following steps of respectively preparing Bi1-xRExFe0.97-yMn0.03TMyO3 precursor solution and CoFe2O4 precursor solution; spin coating on a substrate to prepare a plurality of layers of CoFe2O4 films, spin coating on the CoFe2O4 films to prepare a plurality of layers of Bi1-xRExFe0.97-yMn0.03TMyO3 films and accordingly obtaining a target product. According to the multiferroic Bi1-xRExFe0.97-yMn0.03TMyO3 / CoFe2O4 composite film and the preparation method thereof, the device requirement is simple, the prepared film is good in homogeneity, the doping content is easy to control, the ferroelectric property and the ferromagnetic property of the film are improved to a large extent, and the film is high in residual polarization value and residual polarization value.

The invention relates to samarium-oxide-doped modified lead zirconate titanate ferroelectric ceramic and a preparation method thereof. The ferroelectric ceramic has a composition general formula as follows: Pb1-xSmx(ZryTi1-y)0.98Nb0.02O3, wherein x is more than 0 and not more than 0.1, and y is not smaller than 0.9 and not more than 0.97. The residual polarization strength Pr of the ferroelectric ceramic ranges from 4 mu C / cm<2> to 36 mu C / cm<2>, so that the energy storage density of the ferroelectric ceramic is regulated in a wider range, and the performance requirement of the output power design of a pulse power supply is met. According to the process, formula design, weighing, mixing, powder synthesizing and sintering are carried out according to design requirements; and the addition amount of Sm2O3 is low, and no extra process program is needed. Compared with the traditional process in which a pore-forming agent is added, the preparation method has the advantage that the use of the pore-forming agent and processes such as uniform dispersion are reduced. Accordingly, the invention is simple in process and suitable for scale production.

The invention discloses a composite solid solution film based on sodium bismuth titanate and bismuth ferric and a preparation method thereof. The film is represented by the general formula: (1-x)Na0.5(Bi0.95Ce0.05)0.5TiO(3-x)BiFe0.97Mn0.03O3, the sodium bismuth titanate is Na0.5(Bi0.95Ce0.05)0.5TiO3, and the bismuth ferric is BiFe0.97Mn0.03O3, wherein x is the molar content of BiFe0.97Mn0.03O3, which is greater than 0 and less than 1. According to the invention, the composite solid solution film is prepared by the spinning method-layer by layer annealing process, and does not have an impurityphase except that a pyrochlore impurity phase exists when x is less than or equal to 0.05; and moreover, the film has the advantages of low crystallizing temperature, low electric leakage, great residual polarization, stable dielectric property and the like, and can be well applied to novel high-density integrated piezoelectric ferroelectric devices in the future.

The invention discloses a battery SOC (state of charge) estimation method based on polarization voltage recovery characteristics. The method comprises two parts: analysis of battery polarization voltage characteristics and SOC estimation based on polarization voltage recovery characteristics, wherein in the first part, based on the battery standing voltage curves under different battery SOC, the battery residual polarization voltage in different standing time is extracted, the maximum battery voltage deviation allowable at the SOC error of 3% or below is derived from the OCV-SOC curve, and theminimum standing time for eliminating polarization voltage under different SOC is obtained while guaranteeing the SOC error of 3%; in the second part, according to the battery minimum standing time under different SCO of the same-batch batteries and the law of aging with time, a response surface model is adopted as an approximate model, and an accurate approximation function relationship is obtained in a local scope by using a few data points, so as to obtain the minimum standing time that guarantees the SOC error being within 3% in the whole life cycle of the battery; corresponding battery SOC is estimated according to whether the standing time reaches the minimum standing time.

The invention provides an operating method for realizing multi-bit data storage of a ferroelectric memory, belonging to the technical field of micro-electronics. The method comprises the following steps: in a storage unit of a ferroelectric memory, leading a ferroelectric film to correspondingly generate residual polarization intensity with different magnitudes by additionally increasing different writing pulse voltages and correspondingly defining the residual polarization intensity into different storage states; and reading all the corresponding storage states by a fixed additionally increased right-reading voltage, thereby realizing the multi-bit storage in a single storage unit. The operating method for realizing multi-bit data storage enables a multi-bit storage device to greatly improve the storage density and greatly reduce the production cost.

The invention relates to a lead lutecium niobate-lead zirconate titanate piezoceramic material. The performance is represented through powder diffraction, a scanning electron microscope, dielectric, piezoelectric and ferroelectric measurement, so the morphotropic phase boundary region of a ternary system is determined and the component 43Pb (Lu1 / 2Nb1 / 2) O3-10PbZrO3-47PbTiO3 with the best performance in the morphotropic phase boundary region is obtained, wherein the piezoelectric coefficient d33 is equal to 367 pC / N and Tc is equal to 360 DEG C; the electromechanical coupling property kp is equal to 68 percent; the coercive field Ec is equal to 17 kv / cm; and the residual polarization Pr is equal to 34.45 uC / cm2. The requirement of high technology application such as high-powder sensors, high-strain drivers and the like on the performance of the piezoelectric material can be met, and the requirement of high technology application such as high-powder sensors, high-strain drivers and the like on the using temperature of the piezoelectric material can also be met.

An apparatus for separating fluorescent light from light elastically scattered / reflected from a material illuminated with a broadband illumination source includes a polarization discriminator, which separates the substantially polarized elastically scattered / reflected light from the unpolarized fluorescent light, and a spectrometer to analyze the full and separated reflectance spectra. A linear polarizer may be provided to polarize the illumination source. A method for separating fluorescence light induced in a material by broadband light from an elastic scattering / reflection component includes providing polarization discrimination to separate the components, the fluorescence light being substantially unpolarized, and spectrally analyzing the reflectance components. The method may include linearly polarizing the light source. A fluorescence spectra may be extracted from a minimum reflectance spectra or from a residual polarization reflectance spectra.

Provided is an optical element rotation type Mueller-matrix ellipsometer for solving a problem of measurement accuracy and measurement precision occurring due to residual polarization of a light source, polarization dependence of a photo-detector, measurement values of Fourier coefficients of a high order term in dual optical element rotation type Mueller-matrix ellipsometers according to the related art capable of measuring some or all of components of a Mueller-matrix for any sample.

An embodiment of the invention discloses a method and a device for decomposing objective scattering ingredients of a polarized SAR (synthetic aperture radar). The method comprises the following steps of selecting a volume scattering model based on polarized SAR image data to be processed; extracting the maximum volume scattering power of the polarized SAR image data to be processed according to the polarized SAR image data to be processed and the volume scattering model; acquiring residual polarization coherence matrix of the polarized SAR image data to be processed according to the polarized SAR image data to be processed, the volume scattering model and the maximum volume scattering power value, and performing characteristic decomposition on the residual polarization coherence matrix to obtain the characteristic value and the characteristic vector of the residual polarization coherence matrix; calculating an objective scattering mechanism decision value according to elements of the characteristic vector; and determining even-order scattering and / or surface scattering ingredients of the polarized SAR image data to be processed according to the objective scattering mechanism decision value, and determining power values corresponding to the even-order scattering and / or surface scattering ingredients.

A field-effect transistor is provided which includes: a first nitride semiconductor layer having a lattice constant a1 and a bandgap Eg1; a second nitride semiconductor layer stacked on the first nitride semiconductor layer and having a lattice constant a2 and a bandgap Eg2; a source electrode and a drain electrode formed on the second nitride semiconductor layer; a piezo-effect film formed on the second nitride semiconductor layer in a region between the source electrode and the drain electrode; and a gate electrode formed on a region of the piezo-effect film. The relation between the lattice constants a1 and a2 is a1>a2. The relation between the bandgaps Eg1 and Eg2 is Eg1<Eg2. The residual polarization density at that surface of the piezo-effect film which faces the second nitride semiconductor layer is equal to or higher than the density of electric charges of a two-dimensional electron gas layer at an interface between the first nitride semiconductor layer and the second nitride semiconductor layer, and negative charges are polarized at that surface of the piezo-effect film which faces the second nitride semiconductor layer.

A semiconductor device has a ferroelectric field-effect transistor having a gate portion whose equivalent circuit is composed of a ferroelectric capacitor CF and a paraelectric capacitor CP connected in series, the ferroelectric field-effect transistor having a threshold voltage VTH corresponding to a residual polarization of the ferroelectric capacitor CF, and a control portion (not shown) writing a residual polarization state corresponding to a potential difference between the gate and the back gate of the ferroelectric field-effect transistor by fixing the gate potential of the ferroelectric field-effect transistor (for example, fixing it to a ground potential) and changing the back gate potential of the ferroelectric field-effect transistor (for example, switching it between +10 V and −10 V).

The invention relates to a high-dielectric-constant Bi0.92Ho0.08Fe[1-x]MnxO3 ferroelectric film (x=0.01-0.05) and a preparation method thereof. The film is in a distorted perovskite structure belonging to a rhombohedral system, and has favorable uniformity; and the remanent polarization is 88-116 mu C / cm<2>, and the dielectric constant is 223.1-327.3. The preparation method comprises the following steps: dissolving bismuth nitrate, iron nitrate, holmium nitrate and manganese acetate in an ethylene glycol monomethyl ether-acetic anhydride mixed solution to obtain a precursor solution; evenly spin-coating the precursor solution on a substrate, baking to obtain a dry film, and annealing to obtain a Bi0.92Ho0.08Fe[1-x]MnxO3 film; and spin-coating the precursor solution again, baking and annealing to the required film thickness, thereby obtaining the film. The method has the advantages of simple facility request and controllable doping amount, and can greatly enhance the dielectric properties of the BiFeO3 film.

The invention discloses a preparation method of an organic ferroelectric film with high polarization intensity. PbTiO3 nanosheets and PVDF-TrFE (polyvinylidene fluoride-trifluoroethylene) are taken as main raw materials, firstly, PVDF-TrFE is dissolved in tetrahydrofuran, a proper quantity of PbTiO3 nanosheets are added, and a turbid liquid is obtained; the PbTiO3 nanosheets are uniformly dispersed in a solution through ultrasonic treatment, a clean substrate is spin-coated with the solution uniformly with a spin-coating method, and a film is formed and subjected to heat treatment at the temperature of 180 DEG C. The preparation technology is simple, the process is easy to control, the prepared organic ferroelectric film has an oriented micro-nano structure and also has excellent electrical properties, and the residual polarization is up to 12.4 mu C / cm<2>.

The invention relates to an average length detection device and method as well as a light coherent receiver. The average length detection method is used for detecting whether the average length of an averager used by a polarization crosstalk eliminating device in the receiver is long or short. The method comprises the steps of determining the value of a residual polarization crosstalk coefficient of the receiver, and determining the index of whether the average length of the averager is long or short according to the value of the determined residual polarization crosstalk coefficient.

The invention belongs to the technical field of inorganic functional membrane materials, and relates to a lanthanum and titanium co-doped bismuth ferrite membrane and a preparation method thereof. A sol-gel process and a layer-by-layer annealing process are combined to prepare the lanthanum and titanium co-doped bismuth ferrite membrane Bi(1+Z)(1-Y)LaYFe1XTiXO3(BLTO), wherein the ratios among theelements Bi, La, Fe, Ti and O is (1+Z)(1-Y):Y:(1-X):X:3, the membrane is provided with N layers, N is not smaller than 8 and not larger than 12, and each layer is 100-130 nanometers in thickness. By the aid of the preparation method, a stable and uniform precursor solution can be obtained, and by cooperating with the layer-by-layer annealing process, the prepared membrane is low in leakage currentand high in remanent polarization.

The invention provides a laminated BiFe(0.97-x)Mn0.03TMxO3 / CoFe2O4 multiferroic composite film and a preparation method thereof. The composite film comprises a BiFe(0.97-x)Mn0.03TMxO3 / CoFe2O4 crystallized film and a CoFe2O4 crystallized film which are compounded together. The preparation method comprises the following steps of firstly, preparing a BiFe(0.97-x)Mn0.03TMxO3 / CoFe2O4 precursor solution and a CoFe2O4 precursor solution respectively; and then carrying out spin coating on a substrate to prepare a multi-layer CoFe2O4 film, and then carrying out spin coating on the CoFe2O4 film so as to prepare a multi-layer BiFe(0.97-x)Mn0.03TMxO3 / CoFe2O4 film, thereby obtaining the target product. According to the invention, the equipment requirement is simple; the prepared film is good in uniformity; chemical components are accurate and controllable; the doped amount is easy to control; the ferroelectric properties and the ferromagnetic property of a film are improved greatly, so that the film has high residual polarization value and a residual magnetization value.

The invention provides a LaSrMnCo codoped bismuth ferrite multiferroic film and a preparation method thereof. A Bi(0.97-x)LaxSr0.03Fe0.94Mn0.04Co0.02O3 multiferroic film, namely the LaSrMnCo codoped bismuth ferrite multiferroic film, is prepared by taking bismuth nitrate, lanthanum nitrate, strontium nitrate, ferric nitrate, manganese acetate and cobalt nitrate as raw materials (bismuth nitrate of excessive 5 percent), taking ethylene glycol monomethyl ether and acetic anhydride as solvents and using a spin-coating method and a layer-by-layer annealing process. A sol-gel process is adopted, spin-coating and layer-by-layer annealing methods are adopted, equipment requirements are simple, experimental conditions are easy to realize, the film is suitably prepared on a large surface and an irregularly shaped surface, chemical components are accurately controllable, the multiferroic property of the BiFeO3 film can be improved, the prepared the LaSrMnCo codoped bismuth ferrite multiferroic film has high uniformity and is a multiferroic film with high residual polarization value and low coercive field, and the ferroelectric and dielectric properties of the film are effectively enhanced.

The invention relates to a ferroelectric composite Cu2O visible light water photolysis hydrogen production photocathode and a preparing method thereof. The photocathode is sequentially composed of a BiFeO3 ferroelectric film layer, a gold nano-rod granular layer, a Cu2O film layer and a silicon wafer substrate from top to bottom, and heterojunctions are formed between the Cu2O film layer and the BiFeO3 ferroelectric film layer. According to the ferroelectric composite Cu2O visible light water photolysis hydrogen production photocathode and the preparing method of the photocathode, adverse effects of energy band barriers between the Cu2O film layer and the BiFeO3 ferroelectric film layer are eliminated through gold nano-rod granules by means of the LSPR effect, absorption of visible light with the wave length ranging from 650 nm-750 nm is strengthened, the Cu2O film layer is protected by the BiFeO3 ferroelectric film layer, residual polarization electric fields are used for eliminatingupwarp barriers on photoelectrode / electrolyte interfaces, the water photolysis efficiency and the hydrogen production efficiency are improved, the light current density reaches 91 microampere / cm<2>, and the threshold voltage relative to a reversible hydrogen electrode reaches 1.01 V.

The invention discloses a BiFe1-yMnyO3 epitaxial composite film. The BiFe1-yMnyO3 epitaxial composite film comprises a (100)-orientation LaNiO3 electrode layer, a (001)-orientation Bi4-xLnxTi3O12 transition layer and a (100)-orientation BiFe1-yMnyO3 main body layer in sequence from bottom to top, wherein Ln is lanthanide, x is molar equivalent of the lanthanide and greater than 0 and less than I, y is molar equivalent of Mn and greater than 0 and less than or equal to 0.05. The invention also discloses a preparation method of the BiFe1-yMnyO3 epitaxial composite film. The preparation method combines a chemical solution method with a rapid annealing process by layers, and adopts an epitaxial growth method for preparing the composite film. The prepared composite film consists of three layers, wherein a good epitaxial relationship exists between layers which are both in an epitaxial growth form. The composite film has the advantages of aging prevention, leakage reactance, and high residual polarization (-80 mu C / cm<2>), thus having a good practical prospect in the future ferroelectric and piezoelectric film devices.