89 results about "External bias" patented technology

The invention provides a preparation method of a PdSe2 / Bi2O2Se Van der Waals heterojunction self-driven photoelectric detector, and relates to construction of a two-dimensional material heterostructure and application of the two-dimensional material heterostructure to a photoelectric device. The method comprises the following steps; the preparation method comprises the following steps: preparing nanosheets through a chemical vapor deposition (CVD) process; respectively preparing a PdSe2 nanosheet and a Bi2O2Se nanosheet by adopting the CVD process; and preparing a heterostructure: transferring the PdSe2 nanosheet to the surface of the Bi2O2Se nanosheet in a dry transfer mode to form a Van der Waals heterojunction structure with a clean interface and tight interlayer coupling. The transfer technology keeps the lattice and morphology of the two-dimensional material complete, and reduces organic residues and solvent pollution influences. The heterojunction structure is combined with the narrow band gap of PdSe2 and the broad spectrum response characteristic of Bi2O2Se, and efficient photoelectric conversion from visible light to near-infrared light is achieved. And an electric field is built in the p-n type heterojunction, so that the device is self-driven without external bias voltage, and has the performance of low power consumption and the like. And the method is low in process thermal budget, high in compatibility and suitable for various substrates, and a technical path is provided for construction of the flexible photoelectric detector.

The invention discloses a non-magnetic passive space nonreciprocal antenna housing based on an artificial electromagnetic metamaterial, and relates to the technical field of stealth materials, the non-magnetic passive space nonreciprocal antenna housing comprises antenna housing units which are periodically spliced in a plane, and each antenna housing unit comprises two dielectric substrates which are vertically crossed with each other; artificial microstructure units are arranged on the upper surface and the lower surface of the dielectric substrate; wherein the artificial microstructure unit arranged on the upper surface of the dielectric substrate comprises a double-opening SRR ring, the artificial microstructure unit arranged on the lower surface of the dielectric substrate comprises an asymmetric square opening ring, and the centers of the double-opening SRR ring and the asymmetric square opening ring are asymmetric. The technical problems that in the prior art, a non-reciprocal super-electromagnetic surface needs external magnetic bias or an external power source, preparation is complex, and integration is difficult are solved.

The invention provides an on-chip integrated micro spectrometer based on a cascade diode epitaxial structure and a spectral imager. The on-chip integrated micro spectrometer comprises a substrate, a photoelectric cascade diode epitaxial structure located on the substrate and an electrode, the photoelectric cascade diode epitaxial structure comprises at least two vertically cascaded photodiodes, and each photodiode, as a light detector, can generate spectral response for spectrums in different spectral ranges. The spectral response curve of each photodiode is adjustable along with the change of incident light spectral information and / or external bias voltage, and high-precision spectral measurement, analysis and spectral imaging are realized.

The invention discloses a 2-micron wave band silicon-based germanium surface incidence type high-speed high-responsivity photoelectric detector, which comprises a p-type doped silicon layer 005, the upper surface of the p-type doped silicon layer 005 is provided with a germanium absorption region 006 and a cathode electrode 011, and the cathode electrode 011 surrounds the germanium absorption region 006; the middle part of the germanium absorption area 006 is provided with a porous resonant cavity array 009, the upper surface of the germanium absorption area 006 is provided with an anode electrode 012, and the anode electrode 012 surrounds the porous resonant cavity array 009. Through direct incidence, a 2-micron optical signal output by an external laser source is input into a germanium absorption region, the optical signal in the germanium absorption region is transversely propagated in the germanium absorption region due to a porous resonant cavity array structure, is finally limited and concentrated in the germanium absorption region, and generates two-photon absorption in the germanium absorption region to generate a free electron hole pair; oriented movement is carried out under external bias voltage loaded through the electrodes, and light current is formed.

The invention belongs to the technical field of integrated photonic devices, and particularly relates to an electric tuning silicon nitride waveguide multimode interference coupler based on a two-dimensional material covering layer. In order to solve the problem that an existing silicon nitride photonic device lacks effective electro-optical regulation and control capacity, a two-dimensional material covering layer (such as molybdenum disulfide and tungsten disulfide) is integrated on the surface of a silicon nitride waveguide, and an up-and-down structure of a metal electrode-two-dimensional material-silicon dioxide cladding-silicon nitride waveguide is constructed. When external bias voltage is applied, the effective refractive index of the waveguide mode is changed through evanescent field coupling by means of the electrical refraction effect of the two-dimensional material, and active regulation and control of the optical path of the silicon nitride waveguide without the thermo-optic effect are achieved. Compared with a lithium niobate-silicon nitride heterogeneous integration scheme, the two-dimensional material with the atomic layer thickness is compatible with the CMOS technology, a complex heterogeneous bonding technology is not needed, and the advantage of monolithic integration is achieved. The device is particularly suitable for a reconfigurable optical signal processing device in a silicon-based photon integrated circuit.

A near-infrared radiation detector comprises: a substrate comprising a semiconductor; a substrate electrode formed in contact with the substrate; an active layer formed over the substrate, the active layer comprising a ferroelectric material; and an active layer electrode formed in contact with the active layer and substantially transparent to near-infrared radiation. The detector is operable without applied external bias so that, when near-infrared radiation is incident on the detector, charge carriers are generated by a photovoltaic effect in the substrate / active layer heterojunction and a temperature gradient is generated in the active layer, providing a pyro-phototronic current signal indicative of the near-infrared radiation incident on the detector. Also disclosed is a corresponding method of detecting near-infrared radiation.

The invention discloses a nonlinear quasi bound state terahertz non-magnetic regulation non-reciprocal transmitter and a control method, and belongs to the field of terahertz devices. The nonlinear quasi bound state terahertz non-magnetic regulation non-reciprocal transmitter is formed by periodically arranging and splicing a plurality of unit structures, and each unit structure comprises a silicon carbide substrate and a cylindrical groove gallium arsenide cylinder with the same outer diameter and different inner diameters. The non-linearity of the gallium arsenide material is combined with the asymmetry of the gallium arsenide cylindrical unit structures of the cylindrical grooves with the same outer diameter and different inner diameters, and the non-reciprocal transmission intensity of the terahertz waves is adjusted by changing structural parameters, so that the non-reciprocal transmission regulation and control of the terahertz waves are realized. The nonlinear quasi-bound-state terahertz non-magnetic regulation non-reciprocal transmission device designed by the invention is simple in structure, terahertz wave transmission can be regulated only by changing the incident power of terahertz waves without additionally arranging bias mechanisms such as an external magnetic field, electricity, light, a heat source and the like, and the nonlinear quasi-bound-state terahertz non-magnetic regulation non-reciprocal transmission device is suitable for a future terahertz integrated system.

The invention discloses a frequency reconfigurable conformal array antenna and a preparation method thereof, an antenna metal radiation layer comprises a power distribution network and a reconfigurable antenna unit, a main radiation patch of the reconfigurable antenna unit is a rectangular metal patch, feed is carried out in a side feed mode, and the main radiation patch is a rectangular metal patch. The variable capacitance diode is arranged in the middle of the U-shaped groove between the main radiation patch and the parasitic patch; the 4 * 4 equidistantly arranged reconfigurable antenna units are connected with the T-junction power divider, and the input port of the power divider is connected with an external direct current bias device. By controlling the external bias voltage, the junction capacitance of the variable capacitance diode can be changed, and the reconstruction of the current on the surface of the patch is realized, so that the reconfigurable frequency is realized. The invention also discloses a processing method of the antenna. The antenna disclosed by the invention has the characteristics of low profile, simple structure, low cost, continuously reconfigurable frequency and the like, and the conformal preparation of the antenna can be realized according to the preparation scheme, so that the antenna has a conformal characteristic, and the influence of the antenna on the aerodynamic configuration of a carrier is reduced.

The invention discloses a terahertz non-reciprocal transmission regulator with a double-quasi bound state effect and a method thereof, and belongs to the field of terahertz technologies and devices. The terahertz non-reciprocal transmission device with the double quasi bound state effect is formed by periodically arranging and splicing a plurality of unit structures, and each unit structure is composed of amorphous chalcogenide glass arsenic selenide with unequal rectangular grooves. According to the invention, the nonlinearity of the arsenic selenide material is combined with the asymmetry of the amorphous chalcogenide glass arsenic selenide unit with unequal grooves to generate a double quasi bound state effect, and the first quasi bound state effect and the second quasi bound state effect are utilized to realize the terahertz wave nonreciprocal transmission regulation and control of double frequency points at the same time. The terahertz non-reciprocal transmission device with the double quasi bound state effect designed by the invention is simple in structure, terahertz wave transmission can be regulated and controlled only by changing the incident power of terahertz waves without adding any external bias, and the research of an integratable non-reciprocal device is facilitated.

The invention discloses an ionic elastomer photoelectric sensor based on triplet-triplet annihilation up-conversion and a preparation method of the ionic elastomer photoelectric sensor, and belongs to the technical field of functional materials and photoelectric sensing. The photosensitizer and the luminescence agent form a triplet state-triplet state annihilation up-conversion system. The preparation method comprises the following steps: respectively forming the ionic conductive phase and the optical active phase, mixing the ionic conductive phase and the optical active phase to form a homogeneous system, and curing and molding through photo-initiation polymerization. Under the optical excitation condition of a specific wave band, the ion elastomer can generate measurable electric signal output, so that conversion from an optical signal to an electric signal is realized. The flexible photoelectric sensor can be prepared by curing the material on the surface of an electrode, can work under the condition of no external bias voltage or low bias voltage, has the characteristics of good wavelength selectivity, excellent flexibility and stretchability and the like, and has an application prospect in the fields of wearable sensing and flexible electronics.

The invention relates to a preparation method of a YIG-M type barium ferrite mixed material for a microstrip line circulator. The preparation method comprises the following steps: firstly, preparing YIG precursor powder and barium ferrite powder; pressing the YIG precursor powder into a green body, and sintering to obtain phase-formed YIG ferrite; and crushing the YIG ferrite, mixing the crushed YIG ferrite with the barium ferrite precursor powder according to a mass ratio of 1: 2-2: 1, pressing the mixture into a green body, and carrying out sintering phase formation to obtain the YIG-M type barium ferrite mixed material. The external bias magnetic field of the prepared mixed material is far smaller than that of a traditional YIG material, a good circulation effect can be achieved only through a smaller permanent magnet, and a circulator can be further miniaturized and integrated.

The application relates to the technical field of chips, in particular to an oscillator circuit and an isolated driving chip applying the same, which comprises a first control module, a bias voltage module and a delay module, the first control module is connected to the bias voltage module, the bias voltage module is connected to the delay module, the delay module is connected to a second control module, and the second control module is used for connecting an external under-voltage protection module; when the first control module receives external bias current and the bias voltage module connects an external power supply end VCC, the bias voltage module outputs voltage for the delay module, and the second control module feeds back to the delay module after receiving the voltage output by the under-voltage protection module to generate oscillation. The application has the effect of improving the oscillation frequency.

Provided is a photoelectric conversion element comprising a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) that includes a compound α, and a second electrode film (D), wherein a change rate rd3 represented by formula (i) is 0.020-50.0. Formula (i): rd3=d3a / d3b. In the formula, d3a is a dark current (external bias 3V) after heat treatment under the following conditions, and d3b is a dark current (external bias 3V) without heat treatment. The conditions are that heating is performed for 1-3000 minutes at not lower than 450°C below a reference temperature and not higher than 10°C below the reference temperature, the reference temperature being a 5% mass reduction temperature of the compound α as measured at a pressure of 0.10 MPa, with nitrogen at 200 mL / min, a temperature of 20-550°C, and a temperature increase rate of 10°C / min.

The invention relates to the technical field of semiconductor materials and devices, and discloses an efficient circularly polarized photoelectric detector based on a topological quantum material, the efficient circularly polarized photoelectric detector comprises a substrate and an epitaxial structure grown on the substrate, the substrate is a Bi-modified Si (111) reconstructed surface, and the epitaxial structure is a Bi2Se3 / (Bi1-xInx) 2Se3 superlattice. The invention further provides a preparation method of the efficient circularly polarized photoelectric detector based on the topological quantum material, by designing the superlattice structure of the absorption layer, the conductance effect of circularly polarized light is effectively enhanced, and efficient circularly polarized light detection can be achieved without external bias voltage.

The invention provides a display unit and a display unit control method and device. The display unit comprises an LED array and a mirror image circuit, wherein the mirror image circuit comprises an MOS device; the drain electrode of the MOS device is used for being electrically connected with an external positive voltage generation circuit, the source electrode of the MOS device is electrically connected with the positive electrode of an LED in the LED array, the grid electrode of the MOS device is electrically connected with an external bias voltage generation circuit, and the negative electrode of the LED is used for being electrically connected with an external negative voltage generation circuit. Through the implementation of the scheme of the invention, the MOS device is connected with the LED in series and then is connected with the positive voltage generation circuit and the negative voltage generation circuit, and the output voltage of the negative voltage generation circuit is adjustable, so that the drain-source voltage of the MOS device can be adjusted through the output voltage, the power consumption of the LED is adjusted, the dissipation power of the LED is reduced, and the service life of the LED is prolonged. And the heating condition of the display unit is effectively improved.

The application discloses a kind of quasi-terahertz wave full absorption metasurface absorber and preparation method thereof, the structure of absorber includes: the design of silica layer, graphene multilayer structure and metal base;The structural design of top silica four pyramid;The structural design of multilayer graphene electric control simultaneously.The application uses multilayer graphene to enhance terahertz wave absorption, through the control of external bias voltage, can control the absorption intensity of low-frequency absorption band, realize certain degree of tunability.In terahertz wave band, the metasurface absorber proposed in the application can reach 96.33% average absorption in 0.5-10.0THz band.The application can effectively solve the problem that current absorber can only absorb part of terahertz wave band, open a new road for high performance of terahertz wave absorption field device.

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.

A modulated laser is described, comprising a laser (30) optically coupled to a modulator (50), the modulator (50) having an intrinsic region (52) comprising: a multi-quantum-well material (41); a field control layer (42) having a doping density to enhance the electric field in the multi-quantum-well material; and a collection layer (43) having a band gap higher than that of the multi-quantum-well material (41). Combining the field control layer and the collection layer in the intrinsic region of the modulator of the modulated laser eliminates the need for a trade-off between high speed and low external bias in the modulated laser.

The application relates to a second-order adjustable transistor with a time-domain programmable characteristic and a preparation method thereof. The transistor comprises an insulator substrate, a gate bottom electrode, a ferroelectric blocking layer, a floating gate layer, a tunneling layer, a channel layer and a source and a drain, wherein the blocking layer is a ferroelectric material layer with an electrically programmable polarization state. Through the coupling of the ferroelectric polarization effect and the floating gate charge capture mechanism, the Schottky barrier height at the floating gate interface is regulated, thereby changing the release dynamics of photo-generated carriers, realizing the adjustable relaxation time of photo-generated carriers in the millisecond to second range, and realizing the time-domain programmable regulation of multiple different time factors without the need of a continuous external bias voltage. The device breaks through the limitation of a single time factor of a neuromorphic device and is suitable for in-situ computing scenes such as multi-speed motion perception.

The application discloses an X-ray detection composite material structure and a preparation method thereof. The composite material structure is composed of a conductive substrate (ITO glass), a nickel oxide (NiOx) nanostructure, a lead bromide formamidine (MAPbBr3) single crystal and an upper electrode. The preparation method comprises batching, a liquid phase reaction method and a solution method single crystal growth. The composite material structure prepared by the application can realize self-driven X-ray detection, that is, converts incident X-rays into current signals without an external bias voltage. The application has the advantages of low detection limit, wide detection energy range, high resolution, rapid response, good linearity and low manufacturing cost, and can be applied to X-ray detection, X-ray imaging, light sensors and many other fields.

The invention discloses a sandwich silicon-based heterojunction self-energized broadband photoelectric detector based on a Sb2O3 carrier barrier layer and a preparation method thereof, a Sb2O3 intermediate layer is prepared on a cleaned and pre-masked silicon substrate through an electron beam evaporation method to play a carrier blocking role, then a bismuth compound film is prepared on the Sb2O3 layer, and the Sb2O3 intermediate layer and the bismuth compound film are combined to form the Sb2O3 heterojunction self-energized broadband photoelectric detector based on the Sb2O3 carrier barrier layer. And finally, preparing a pair of electrodes on the surfaces of the silicon substrate and the bismuthide film to obtain the bismuthide / Sb2O3 / silicon sandwich heterojunction photoelectric detector. Compared with a bismuth compound / silicon heterojunction detector, the existence of the Sb2O3 carrier barrier layer can effectively reduce dark current and improve light current, excellent detection performance on ultraviolet-visible-infrared bands under the condition of room temperature and without external bias voltage is achieved, the detection rate and responsivity are improved by 2-4 orders of magnitude, the maximum is 1012 Jones and 10 <-1 > A / W, and the detection efficiency and responsivity are improved by 2-4 orders of magnitudes, the maximum is 10 <-1 > Jones and 10 <-1 > A / W. And meanwhile, excellent stability and a unit device imaging function are realized.

This invention discloses a colloidal quantum dot dual-mode detector and its fabrication method. The colloidal quantum dot dual-mode detector comprises, from bottom to top, a substrate, a bottom electrode, a photodiode layer, an electric field modulation layer, a gain device layer, and a top electrode, stacked sequentially. Through an innovative vertically stacked bandgap design, this invention integrates a colloidal quantum dot photodiode and a multi-junction gain structure within a single device for the first time. The device intelligently modulates the direction of the internal electric field using an external bias voltage, achieving precise and rapid switching between high-gain weak-light detection and high-linearity strong-light detection modes. It also fundamentally suppresses dark current, solving the problems of excessive noise and poor stability in traditional gain devices. Furthermore, the device maintains high response speed and excellent stability while possessing a compact structure and high compatibility with existing planar processes, demonstrating excellent process compatibility and large-scale fabrication potential, providing a stable and reliable technical foundation for the development of high-resolution infrared imaging devices.

The application discloses a photoelectric detection system based on pyroelectric optoelectronic effect, which comprises a self-powered detector, a light modulation unit and a signal processing and translation unit; the light modulation unit is used for modulating information of excitation light according to a modulation instruction output by an instruction controller, and generating an encoded light signal carrying original information; the self-powered detector is used for receiving the encoded light signal based on pyroelectric optoelectronic effect without external bias, and generating a current signal corresponding to the encoded light signal; and the signal processing and translation unit is used for processing the current signal, translating and outputting the original information. The application can realize integrated detection and decoding of optical information, improve system integration and reduce power consumption.

The invention provides a tunneling photodiode with a bias voltage regulation and control dynamic range and a preparation method and application thereof, and belongs to the technical field of photodiodes. The diode comprises a conductive substrate, a first light absorption layer, a tunneling layer, a second light absorption layer and a metal electrode which are sequentially stacked from bottom to top, and the first light absorption layer and the second light absorption layer form an I-type energy band heterojunction. The ultra-thin tunneling layer is introduced to the I-type heterojunction interface to construct the tunneling photodiode, so that the dynamic range of the tunneling photodiode can be continuously and quickly adjusted by adjusting the external bias voltage, and the tunneling photodiode can adapt to different illumination conditions. Under positive bias voltage, the device has high gain and is suitable for strong light detection; under reverse bias, the gain of the device is reduced, the saturation effect under strong light is avoided, and the device is suitable for medium-strong light detection; under zero bias voltage, the device has extremely low dark current, the signal-to-noise ratio is optimized, the weak light detection sensitivity is improved, and the device is suitable for weak light detection, so that a high dynamic range is realized.

The invention discloses a gain-adjustable bionic photoreceptor based on a substrate bias effect and a preparation method thereof. The device comprises an MOS field effect transistor and a photodiode, a substrate of the MOS field effect transistor is in a suspended state, and the photodiode works through a photosensitive PN junction. Under the condition that proper bias voltage is applied, a conducting channel of the MOS transistor is formed. When light irradiates the device, the longitudinal PN junction injects photon-generated carriers into the substrate of the MOS transistor by using a built-in electric field, so that the potential of the substrate is changed, and the threshold voltage of the MOS transistor is reduced. Under the condition that the external bias voltage remains unchanged, the reduction of the threshold voltage of the MOS transistor causes the increase of the drain output current, and the increase of the photoresponse current of the device is realized. The photoreceptor can realize gain adjustment and has an efficient light response characteristic. Similar to a photoreceptor in a human retina, the device has adjustable gain and wide dynamic range of visible light spectrum. Meanwhile, the device is compatible with a standard CMOS technology, large-scale array integration can be achieved, and the device is expected to be applied to an intelligent robot visual system in the future.

The present invention discloses an external bias pixel structure of a light receiving stage circuit in a dynamic vision sensor pixel. The external bias pixel structure comprises a photodiode, a logarithmic tube, an amplifier tube, a switch tube, and a bias tube. The bias tube, the switch tube, and the amplifier tube are sequentially connected in series, wherein the source of the bias tube is connected to a power supply, the drain of the bias tube is connected to the drain of the switch tube, the source of the switch tube is connected to the drain of the amplifier tube, and the source of the amplifier tube is grounded. The gate of the bias tube is connected to V bias Signal connection, the gate of the switch tube is connected to V cpr Signal connection, the source of the switching tube and the drain of the amplifier tube are also connected to the gate of the logarithmic tube, the drain of the logarithmic tube is connected to the power supply, the source of the logarithmic tube is connected to the negative electrode of the photodiode, the positive electrode of the photodiode is grounded, and the source of the logarithmic tube and the negative electrode of the photodiode are also connected to the gate of the amplifier tube.

The present invention relates to a read sense amplifier circuit and system that enables read operations over a wide power range by using a low reference resistor and securing gain through a two-stage operational amplifier circuit, and can also detect low fuse resistance to secure a sensing resistance margin and improve yield, and a memory cell read method using the same. The above read sense amplifier circuit comprises a current mirror circuit stage that receives a reference current from an external bias circuit and mirrors the reference current through a plurality of paths, a reference resistor stage including a reference resistor and an NMOS transistor that activates the reference resistor, a precharge circuit stage that receives a precharge signal and precharges a reference bit line connected to the reference resistor based on the precharge signal, an amplifier circuit stage that senses cell data for a cell corresponding to the selected fuse using the voltage difference between the resistance of the selected fuse corresponding to the selected cell and the reference resistor, and a buffer circuit stage that outputs the sensed data, wherein the amplifier circuit stage includes a plurality of PMOS transistors, and at least one input stage of the plurality of PMOS transistors of the amplifier circuit stage may be electrically connected to a connection resistor.

The application discloses a kind of multi-field regulated vector optoelectronic logic device and preparation method thereof, belong to vector optoelectronic logic device technical field, by integrating two-dimensional bismuth selenide material on LNOI substrate, using the sensitive characteristics of two-dimensional bismuth selenide material photo-thermal-electric response to laser position, power and external bias, a kind of multi-field regulated vector optoelectronic logic device is prepared, and vector optoelectronic logic device can realize different logic input values by regulating laser light source position, laser power size and external bias, so as to realize the output value of different size and vector direction photoelectric current.

The invention provides an LDO circuit. The LDO circuit comprises a chopping stabilization error amplifier, a first transistor and a feedback loop. The chopping stabilization error amplifier comprises an in-phase input end, an inverted input end, a current bias end, a first voltage bias end, a second voltage bias end, a third voltage bias end, a clock end, a power supply end, a reference ground end and an output end. The inverted input end of the chopping stabilization error amplifier is connected with reference voltage, the current bias end is connected with external bias current, the first to third voltage bias ends are correspondingly connected with three bias voltages respectively, the clock end is connected with a chopping clock source, the power end is connected with a power supply, and the reference ground end is grounded; the grid electrode of the first transistor is connected with the output end of the chopping stabilization error amplifier, the source electrode of the first transistor is connected with a power supply, and the drain electrode of the first transistor serves as the output end of the LDO circuit and is connected to the in-phase input end of the chopping stabilization error amplifier through the feedback loop. According to the invention, flicker noise can be reduced.