A near-field heat flux control device and its control method

Abstract

This invention discloses a near-field heat flux control device and its control method, relating to the field of near-field thermal radiation control technology. The device includes a first radiator, a second radiator, and an intermediate control layer. The intermediate control layer, disposed between the two radiators, is composed of a narrow bandgap semiconductor material. Its carrier concentration changes smoothly with temperature, and its dielectric response characteristics continuously change with temperature, driving a frequency shift in the plasma frequency. The temperature of the intermediate control layer can be adjusted to amplify or suppress the heat flux. By using a narrow bandgap semiconductor and utilizing the temperature change of carrier concentration to drive a continuous blue shift in the plasma frequency, a spectral sweep effect is induced between the two radiators. This differs from the lattice abrupt change mechanism of phase change materials. Under an idealized temperature-shifting material model, the theoretical heat flux amplification factor of the device can reach over 100. When InSb is used as the intermediate control layer and simulations are performed based on its actual material parameters, the device maintains stable amplification performance over a continuous temperature range of approximately 40K.

Description

Technical Field

[0001] This invention relates to the field of near-field thermal radiation control technology, and in particular to a near-field heat flow control device and its control method. Background Technology

[0002] With the exponential growth in the integration of microelectronic devices and the increasing urgency of autonomous thermal management for spacecraft, traditional passive heat dissipation technologies are struggling to cope with the challenges of high heat flux density and complex temperature variations. Near-field thermal radiation modulation technology, as an emerging active thermal management method, can achieve precise control of heat flux at the subwavelength scale, demonstrating enormous application potential in areas such as high-performance chip heat dissipation, deep space probe thermal control, and thermal logic circuits.

[0003] Existing near-field thermal radiation modulation devices mainly rely on phase change materials to achieve heat flow modulation. For example, vanadium dioxide (vanadium dioxide) is used. Phase change materials (PCMs) are used as modulation layers, utilizing the abrupt change in their lattice structure near the phase transition temperature to alter the optical properties of the material, thereby modulating radiative heat flux. These devices can achieve high heat flux modulation ratios near the phase transition point. However, the operating principle of PCMs is limited by the abrupt change in lattice structure, resulting in devices that can only operate effectively within a very narrow temperature range (typically less than 10K) near the phase transition temperature. Furthermore, the severe thermal hysteresis during the phase transition process significantly impacts the stability and repeatability of the devices. In addition, the gain oscillation problem near the critical temperature of PCMs also limits further improvements in device performance.

[0004] Chinese patent CN114050198A discloses a radiative heat flow control device based on semiconductor materials. The device includes a first radiator and a second radiator disposed opposite to each other. The first radiator has a semiconductor material layer, which contains intrinsic semiconductor material or has a carrier doping concentration of less than 10⁻⁶. 16 cm -3 The technology utilizes the change in carrier concentration within the semiconductor material with temperature, leading to a change in local electromagnetic state density, thereby controlling radiative heat flux. However, this patent document does not address the impact of the intermediate control layer thickness on device performance, nor does it provide design guidelines for thickness optimization. In practical applications, when the intermediate layer thickness is small, strong coupling occurs between polaritons on the upper and lower surfaces of the film, inducing mode splitting and causing spectral energy to disperse into multiple transmission channels, reducing radiative coupling efficiency and overall device performance. Furthermore, this document does not disclose quantitative performance indicators for the device over a wide temperature range, making it impossible to assess its actual heat flux amplification capability and operating temperature range.

[0005] In terms of device performance evaluation, existing technologies typically use amplification factors defined by differentials. This is used to measure the amplification performance of heat-flux-controlled devices. However, when the net gate heat flux... When the value approaches zero, the denominator of the definition approaches zero, causing the amplification factor to approach infinity. This makes it impossible to truly reflect the actual amplification performance of the device over a wide temperature range, and it also fails to provide an effective evaluation standard for engineering applications.

[0006] Therefore, a new near-field heat flux control technology is needed to achieve stable heat flux control over a wide temperature range, while avoiding the inherent thermal hysteresis and instability problems of phase change materials, and providing an accurate performance evaluation method to meet the needs of practical applications such as heat dissipation of micro-nano chips and thermal control of deep space probes. Summary of the Invention

[0007] The purpose of this invention is to provide a near-field heat flux control device and its control method to solve the following technical problems existing in the prior art:

[0008] (1) Existing near-field thermal transistors rely on phase change materials such as vanadium dioxide. Their working principle is limited by the abrupt change in the crystal structure, which means that the device can only work effectively in a very narrow temperature range (usually less than 10K) near the phase change temperature. Furthermore, the phase change process is accompanied by severe thermal hysteresis and gain oscillation, which seriously affects the stability, repeatability and practical application capability of the device.

[0009] (2) The semiconductor thermal flow control devices in the prior art do not involve the influence of the thickness of the intermediate control layer on the device performance. When the thickness of the intermediate layer is small, the polaritons on the upper and lower surfaces of the thin film will be strongly coupled, which will induce mode splitting and cause the spectral energy to be dispersed to multiple transmission channels, reducing the radiation coupling efficiency and the overall performance of the device.

[0010] (3) Existing technology uses the amplification factor defined by differential. To measure the amplification performance of heat flux-controlled devices, when the net gate heat flux approaches zero, the denominator of the definition approaches zero, causing the amplification factor to approach infinity, which cannot truly reflect the actual amplification performance of the device over a wide temperature range.

[0011] To achieve the above objectives, embodiments of the present invention provide a near-field heat flux control device, including a first radiator and a second radiator, and an intermediate control layer independently disposed between the first radiator and the second radiator. Subwavelength-scale vacuum gaps are respectively provided between the first radiator and the intermediate control layer, and between the intermediate control layer and the second radiator. The intermediate control layer is made of a narrow bandgap semiconductor material, and the carrier concentration of the narrow bandgap semiconductor material changes smoothly with temperature, so that the dielectric response characteristics of the intermediate control layer change continuously with temperature and drive the plasma frequency to shift, thereby continuously adjusting the radiative coupling between the first radiator and the second radiator to amplify or suppress heat flux.

[0012] Preferably, the thickness of the intermediate control layer is 80 nm to 200 nm.

[0013] Preferably, the narrow bandgap semiconductor material is indium antimonide.

[0014] Preferably, the first radiator and the second radiator are made of polar crystalline materials.

[0015] Preferably, the polar crystal material is silicon dioxide or silicon carbide.

[0016] Preferably, the distance of the vacuum gap is 10 nm to 1 μm.

[0017] Preferably, the dielectric response characteristics of the intermediate control layer are described by the Drud-Lorentz model, introducing a temperature-dependent parameter. The temperature-dependent parameter As the temperature of the intermediate control layer changes continuously:

[0018] ;

[0019] In the formula, This is the upper limit of the frequency offset. This represents the lower limit of the frequency offset. The temperature of the intermediate control layer, This represents the upper limit of the temperature. This represents the lower limit of the temperature. The adjustment factor is used to dynamically control the rate of change of frequency with temperature. The above temperature-dependent parameter model is used to uniformly characterize the law of continuous change of dielectric response of intermediate control layer material with temperature, and is not limited to a specific narrow bandgap semiconductor material; for other narrow bandgap semiconductor materials with smooth change of carrier concentration with temperature and capable of driving continuous frequency shift of plasma, their temperature-frequency shift response characteristics can be characterized by adjusting the model parameters.

[0020] Preferably, when the material of the intermediate control layer is indium antimonide, the materials of the first radiator and the second radiator are silicon dioxide, and the device meets the preset structural parameters, the heat flux amplification factor of the device is greater than 20 when the temperature of the intermediate control layer varies from 30K to 50K.

[0021] This invention also provides a near-field heat flux control method, which is applied to a near-field thermal radiation system including a first radiator and a second radiator. The method includes the following steps: setting an intermediate control layer made of a narrow bandgap semiconductor material between the first radiator and the second radiator; driving the plasma frequency of the intermediate control layer to shift by controlling the temperature of the intermediate control layer, thereby forming a continuously changing frequency radiation coupling between the first radiator and the second radiator; and realizing the amplification or suppression control of the near-field radiative heat flux.

[0022] Preferably, the near-field heat flux control method further includes calculating a heat flux amplification factor based on the heat flux difference in monotonic intervals; the heat flux amplification factor Calculated using the following formula: ,in This represents the difference in heat flux received by the second radiator within the monotonic interval. This represents the difference in net heat flux of the intermediate control layer at the corresponding temperature.

[0023] As can be seen from the above technical solutions, this invention application has the following beneficial effects:

[0024] (1) Wide-temperature-range continuous and stable operation was achieved. Indium antimonide narrow bandgap semiconductor was used as the intermediate control layer. Taking advantage of its physical property of smooth change of carrier concentration with temperature, the plasma frequency was continuously blue-shifted, avoiding the inherent thermal hysteresis and gain oscillation problems of phase change materials near the critical point. Simulation results show that when InSb is used as the intermediate control layer and simulation is performed based on its actual material parameters, the device achieves stable operation in a continuous temperature range of about 40K. This performance is more than four times that of existing phase change material devices (less than 10K), providing technical support for wide-temperature-range heat flux control.

[0025] (2) Effective improvement in heat flux amplification performance. Under the given conditions, 200 nm is an optimal thickness, which is a better geometric scale that can effectively suppress multimodal interference and improve radiation coupling efficiency. It effectively suppresses mode splitting induced by strong coupling of polaritons on the upper and lower surfaces of the thin film, and highly concentrates spectral energy into a single high-gradient transmission channel. Simulation results show that the heat flux amplification factor reaches 118.44 when using an ideal temperature frequency shift material and 22.19 when using indium antimonide as the actual material. Compared with the phase change material scheme, it shows a wider stable operating temperature range, providing performance assurance for efficient heat flux control.

[0026] (3) It provides an accurate performance evaluation method. In view of the mathematical defect that the traditional differential definition diverges at singular points, an effective interval amplification factor calculation method based on the difference of heat flux in monotonic intervals is introduced. This method overcomes the problem that the amplification factor tends to infinity when the net heat flux of the gate approaches zero. It can truly reflect the actual amplification performance of the device in a wide temperature range and provides a reliable evaluation standard for engineering applications.

[0027] (4) Improved device manufacturing feasibility. Compared with existing technologies that require complex micro-nano array structures, this invention adopts a planar thin film structure, which simplifies the manufacturing process and reduces processing difficulty and cost. The 200nm gate thickness is easy to prepare using mature processes such as molecular beam epitaxy or magnetron sputtering, and the 100nm spacing can be precisely controlled by micro-nano fabrication technology. The overall structural design takes into account both high performance and manufacturing feasibility.

[0028] (5) Expanded application scenarios. The device of the present invention can be integrated into the chip package as a heat flow regulation unit for dynamic thermal management of key hot spots; it can be used as a heat flow regulation unit in the thermal control system of spacecraft; it can also be used as a basic component in thermal logic devices for related heat flow regulation and information processing applications, and has application potential in the fields of high-performance chip heat dissipation, deep space probe thermal control and thermal logic circuits. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Referring to the drawings will make the features and advantages of the present invention clearer. The drawings are illustrative and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0030] Figure 1 This is a schematic diagram of the structure of a near-field heat flow control device provided by the present invention;

[0031] Figure 2 This is a comparative schematic diagram of the working mechanism of different gate materials in an idealized thermal radiation transistor, where (a) is a schematic diagram of the working mechanism of an existing phase change material thermal radiation transistor, and (b) is a schematic diagram of the working mechanism of a temperature frequency shift material thermal radiation transistor used in this invention.

[0032] Figure 3 The graphs show the heat flux characteristics and mode energy transfer efficiency distribution of a near-field heat flux modulated device with a gate thickness of 200 nm; where (a) is the heat flux density as a function of gate temperature, and (b), (c), and (d) are graphs for different gate temperatures. (300K, 325K, 350K) modes A schematic diagram of energy transfer efficiency distribution, in which... and The gate thickness is respectively Symmetric and antisymmetric modes generated by the wedge splitting mode;

[0033] Figure 4 The graphs show the heat flux characteristics and mode energy transfer efficiency distribution of a near-field heat flux modulated device with a gate thickness of 50 nm. (a) is a graph showing the heat flux density as a function of gate temperature, and (b), (c), (d), and (e) are graphs showing the heat flux density at different gate temperatures. (300K, 322K, 330K, 350K) modes A schematic diagram of energy transfer efficiency distribution, in which... and The gate thickness is respectively Symmetric and antisymmetric modes generated by the wedge splitting mode;

[0034] Figure 5 This is a schematic diagram showing the relationship between the thickness of the intermediate control layer and the heat flux amplification factor, where the size of the circle indicates the temperature range in which the amplification factor exists;

[0035] Figure 6 This is a graph showing the change in heat flux density as a function of gate temperature in a near-field heat flux control device using indium antimonide as the gate material. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The near-field heat flux control device and its control method disclosed in this invention are based on the narrow bandgap semiconductor phonon-plasmonic frequency shift mechanism to achieve wide-temperature-range near-field heat flux control. This abandons the "hard-switching" mode of traditional phase change materials that relies on abrupt changes in lattice structure. Instead, it drives a smooth change in the carrier concentration of the material through temperature, thereby inducing a continuous frequency shift in the plasma frequency, achieving continuous and stable control of radiative heat flux. At the same time, it optimizes the device topology and performance evaluation method, solving the industry pain points of existing near-field thermal transistors, such as narrow operating temperature range, severe thermal hysteresis, poor stability, and distorted performance evaluation.

[0038] The specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the technical terms in the following embodiments are defined as follows: the first radiator refers to the source electrode that emits thermal radiation; the second radiator refers to the drain electrode that receives thermal radiation; the intermediate control layer refers to the gate electrode located between the source and drain electrodes; narrow bandgap semiconductor material refers to a semiconductor material with a bandgap width of less than 1 eV, such as indium antimonide; subwavelength scale refers to a distance range smaller than the characteristic wavelength of thermal radiation; plasma frequency refers to the characteristic frequency of the collective oscillation of free carriers; heat flux amplification factor refers to the ratio of the output heat flux change to the input control heat flux change.

[0039] Example 1: Structural Implementation of Near-Field Heat Fluid Control Device

[0040] Please see Figure 1 The near-field heat flow control device provided in this embodiment is a three-plate layered planar structure, which includes a first radiator (source / emitter), an intermediate control layer (gate), and a second radiator (drain / receiver). The intermediate control layer is independently disposed between the first radiator and the second radiator, and the three are parallel to each other and coaxially arranged.

[0041] The temperature of the first radiator is maintained at a first temperature. (Source temperature), the temperature of the second radiator is maintained at the second temperature. (Drain temperature), and satisfy A first vacuum gap is provided between the first radiator and the intermediate control layer, and the distance of the first vacuum gap is... A second vacuum gap is provided between the intermediate control layer and the second radiator, and the distance of the second vacuum gap is [missing information]. The and All are subwavelength scales. In this embodiment... In other alternative embodiments, the vacuum gap distance can be adjusted within the range of 10nm to 1μm according to application requirements.

[0042] Both the first and second radiators are made of polar crystalline materials; in this embodiment, silicon carbide (SiC) is selected. In other alternative embodiments, other polar crystalline materials such as silicon dioxide (SiO2) can be used. The thickness of the first radiator is... The thickness of the second radiator is In this embodiment , All thicknesses are set to semi-infinite to avoid the influence of boundary effects on the dielectric response of the material. In actual engineering implementation, the thickness can be adjusted to finite thickness of 100 nm or more depending on the fabrication process.

[0043] The intermediate control layer is an active control unit, fabricated using a narrow bandgap semiconductor material. Its core utilizes the physical property of smooth carrier concentration change with temperature; in this embodiment, indium antimonide (InSb) is selected, whose carrier concentration increases exponentially with increasing temperature, thereby driving a continuous change in the material's dielectric response characteristics and achieving a continuous frequency shift in the plasma. The thickness of the intermediate control layer is... In this embodiment, the thickness is preferably set to 200nm. In other optional embodiments, the thickness can be adjusted in the range of 80nm to 200nm to adapt to different operating temperature ranges and amplification performance requirements. At the same time, the intermediate control layer can also be made of other narrow bandgap semiconductor materials that have a smooth change in carrier concentration with temperature and can cause continuous change in dielectric response and continuous frequency shift of plasma frequency.

[0044] The temperature of the intermediate control layer The gate temperature can be regulated by an external heating / cooling unit to bring the intermediate control layer to the target steady-state temperature, at which point the net heat flow of the intermediate control layer is... The heat flow received by the drain Heat flow equal to source loss Through regulation This allows for the amplification or suppression of near-field radiative heat flow between the source and drain.

[0045] Example 2: Working Mechanism and Theoretical Model of the Device

[0046] This embodiment elaborates on the dielectric response model, temperature frequency shift mechanism, and near-field heat transfer theoretical model of the device of the present invention, providing theoretical support for device design and performance optimization.

[0047] 1. Dielectric response model of polar crystal materials

[0048] In this invention, the polar crystal material (SiC, for example) used in the first and second radiators is characterized by its dielectric function using the Lorentz model, and the specific expression is as follows:

[0049] ;

[0050] In the formula, The dielectric constant of SiC is infinite frequency. ; For longitudinal optical phonon frequencies, SiC's ; For the transverse optical phonon frequency, SiC's ; For the attenuation coefficient, SiC's ; ω is the angular frequency of the incident electromagnetic wave; It is the imaginary unit.

[0051] 2. Temperature-dependent frequency-shift dielectric model

[0052] For the temperature-shifting material used in the intermediate control layer, this invention introduces a temperature-dependent parameter into the Lorentz model. A Drud-Lorentz dielectric response model was constructed to characterize the continuous variation of the material's dielectric properties with temperature. The specific expression is as follows:

[0053] ;

[0054] In the formula, This is a temperature-dependent frequency offset parameter, the value of which depends on the material properties and the temperature of the two electrodes. The specific expression is:

[0055] ;

[0056] In the formula, This is the upper limit of the frequency offset. This represents the lower limit of the frequency offset. The temperature of the intermediate control layer, This represents the upper limit of the temperature. This is the lower limit of the temperature; in this embodiment, and Based on source and electrode temperatures respectively With drain temperature Decide; It is a regulating factor used to dynamically control the rate of change of frequency with temperature.

[0057] By adjusting The value of [value] can achieve different temperature-frequency shift response characteristics: when hour, It exhibits high sensitivity to temperature changes, especially when the temperature is close to... When a sudden change occurs, it exhibits characteristics similar to phase change materials; when hour, It can change approximately linearly with temperature, exhibiting a continuous temperature frequency shift characteristic, which can be used as a model characterization in a preferred embodiment of the present invention. It should be noted that the above Ω–β parameterization model aims to provide a unified description of a class of narrow bandgap semiconductor materials with temperature-driven continuous carrier concentration variation; for different materials, it is only necessary to redefine the parameterization based on their material parameters. , and The range of values ​​for can characterize its corresponding temperature-frequency shift response characteristics. In this embodiment, for an idealized temperature-frequency shift material, a range is set... , , This enables the frequency to be linearly and continuously adjustable with temperature.

[0058] 3. Comparison of the mechanism of action of this invention with existing phase change materials

[0059] Please see Figure 2 This figure is a schematic diagram comparing the working mechanisms of different gate materials in an idealized thermal radiation transistor, used to intuitively reveal the core advantages of the temperature frequency shift material of this invention compared with traditional phase change materials.

[0060] Figure 2 In the diagram, the horizontal axis represents the gate temperature at... Variation within the range, vertical axis The normalized frequency is indicated by the normalized frequency, and the radiation coupling intensity at the corresponding temperature is marked on the right side of the figure. The black solid line represents the frequency response curve of each gate material as a function of temperature, and the red data points mark the radiation coupling intensity at the corresponding temperature.

[0061] in, Figure 2 (a) is a schematic diagram of the working mechanism of an existing phase change material thermal radiation transistor: the gate uses a phase change material of finite thickness (such as VO2), and semi-infinitely extended polar materials are symmetrically arranged on both sides. As the temperature increases, the phase change material reaches a critical temperature... A lattice structure abrupt change occurs nearby, and its frequency response is related to the coupling strength. A precipitous change occurred nearby, and it was only possible to... Effective magnification is achieved within an extremely narrow range, with an effective working range span of only [missing information]. (Typically less than 10K), and accompanied by severe thermal hysteresis and gain oscillation.

[0062] Figure 2 Image (b) is a schematic diagram illustrating the working mechanism of the temperature-shifting material thermal radiation transistor (near-field heat flow control device) used in this invention: the gate is composed of a temperature-shifting material of finite thickness, and both sides are also polar materials. The temperature-shifting material of this invention exhibits a continuous and smooth frequency response to temperature changes. Within the negative differential thermal resistance range, the effective operating range span is close to It can maintain high coupling efficiency and stable amplification performance over a wider temperature range, which helps to avoid the core defects of narrow temperature range, thermal hysteresis and poor stability caused by lattice abrupt changes in phase change materials, and provides greater flexibility and adaptability for the engineering application of devices.

[0063] 4. Theoretical Model of Near-Field Heat Transfer

[0064] Based on fluctuation electrodynamics and N-body near-field heat transfer theory, this invention calculates the near-field radiative heat flux of a tri-plate system. In the tri-plate system, the tunneling photon flux (i.e., heat flux) received by the second radiator (drain electrode) The expression for ) is:

[0065] ;

[0066] In the formula, To reduce Planck's constant; The parallel wave vector of the surface of the multilayer system; The polarization state of electromagnetic waves, including polarization and polarization; The modes of each polarization state between the source and gate The coupling efficiency (transmission coefficient). This represents the coupling efficiency between the gate and drain in each mode under the corresponding polarization state. This represents the average photon number difference between the source and gate electrodes. This represents the difference in average photon count between the gate and drain electrodes, where the average photon count is... Satisfies the Bose-Einstein distribution: , Boltzmann's constant, This represents the thermodynamic temperature of the corresponding electrode.

[0067] Among them, transmission coefficient and By characterizing the optical reflectivity and transmission coefficient of each electrode in the system, the imaginary part of the surface wave vector component of the multilayer structure is introduced. ( (where the speed is light in a vacuum) are expressed in the following ways:

[0068] ;

[0069] ;

[0070] In the formula, , , These represent the optical reflectivities of the source, gate, and drain electrodes in their respective polarization states. This represents the optical transmission coefficient of the gate in the corresponding polarization state. The equivalent reflectivity of the source-gate coupling system is given by [value]. This represents the vacuum gap distance between the corresponding electrodes.

[0071] Correspondingly, the heat flow lost by the first radiator (source electrode) The expression is:

[0072] ;

[0073] The physical meaning of each parameter in the formula is the same as that in the above formula, and can be obtained by replacing the temperature and transport coefficient of the corresponding electrode.

[0074] Under steady-state conditions without continuous external thermal excitation, the net heat flux of the intermediate control layer (gate) is 0, meaning the heat flux received by the gate is equal to the heat flux lost, satisfying:

[0075] .

[0076] Based on this steady-state condition, it can be determined that at a given source temperature... With drain temperature Below, the equilibrium temperature of the intermediate control layer ; The temperature of the intermediate control layer is changed through external regulation. This can change its dielectric response characteristics and the system's radiation coupling efficiency, thereby enabling active control of the radiative heat flow between the source and drain.

[0077] Example 3: Optimized Implementation of Device Performance Evaluation Method

[0078] To address the mathematical deficiencies of existing technologies that use differential definitions for heat flux amplification factors, this embodiment provides an effective interval amplification factor calculation method based on the difference in heat flux over monotonic intervals. This method serves as an evaluation standard for device performance, accurately reflecting the actual amplification performance of the device over a wide temperature range.

[0079] In existing technologies, the amplification effect of a thermal transistor is typically defined using a differential, expressed as:

[0080] ;

[0081] This definition has an inherent flaw: when the denominator... When it approaches 0, the amplification factor It will tend towards infinity, completely ignoring molecules. The contribution of the data cannot truly reflect the actual heat flux amplification capability of the device, and is especially unsuitable for evaluating the performance of devices that operate continuously over a wide temperature range.

[0082] The optimized effective range magnification factor of this invention is obtained through statistical analysis. and The common monotonic interval is used to calculate the amplification factor based on the heat flux difference between the two ends of the interval, thereby achieving effective characterization of the device's performance across the entire operating temperature range. The specific expression is as follows:

[0083] ;

[0084] In the formula, The maximum difference in heat flux received by the second radiator within the monotonic interval is specifically:

[0085] ;

[0086] in, This represents the maximum heat flux received by the drain electrode within the monotonic interval. This represents the minimum heat flux received by the drain electrode within the monotonic interval. This represents the absolute value of the difference in net heat flux between the two ends of the monotonic interval.

[0087] This optimized evaluation method overcomes the problem of the traditional differential definition diverging at singular points, and can truly reflect the actual amplification performance of the device over a wide temperature range, providing a reliable evaluation standard for the engineering application of the device.

[0088] Example 4: Analysis of the Amplification Mechanism and Mode Coupling Characteristics of the Device

[0089] This embodiment, combined with simulation results, elaborates in detail the thermal flux amplification mechanism, mode splitting characteristics, and coupling-decoupling process of the device of the present invention, and verifies the working principle and performance advantages of the device.

[0090] The simulation conditions for this embodiment are: source temperature Drain temperature The distance between the source and gate, and between the gate and drain. Both the source and drain electrodes are made of SiC material, and the intermediate control layer is made of an idealized temperature frequency shifting material. Simulation analysis was performed for two gate thicknesses of 200nm and 50nm.

[0091] 1. The heat flow amplification effect and negative differential thermal resistance characteristics of the device

[0092] Please see Figure 3 In (a), when the thickness of the intermediate control layer At the gate temperature Within this range, there are two monotonic intervals exhibiting heat flux amplification effects:

[0093] ① Monotonically increasing interval Within this range, the device exhibits a significant heat flux amplification effect, and the effective heat flux amplification factor calculated based on the optimized evaluation method of this invention reaches 118.44.

[0094] ② Monotonically decreasing interval Within this range, the amplification effect of the device is relatively small, and the effective heat flux amplification factor is 3.34.

[0095] The difference in amplification between the two monotonic intervals stems from the different mechanisms of negative differential thermal resistance (NDTR): the amplification effect in the monotonically increasing region originates from the drain differential thermal resistance. The contribution of the monotonically decreasing region is due to the source differential thermal resistance. The contribution of negative differential thermal resistance is the core cause of the heat flow amplification effect in the device. Its essence is the mismatch of phonon bands between two interface particles. The heat flow behavior depends on the relative advantage between the decrease of thermal gradient and the increase of band overlap. When the contribution of the increase of band overlap exceeds the effect of the decrease of thermal gradient, the negative differential thermal resistance and heat flow amplification effect are generated.

[0096] Please see Figure 4 In (a), when the thickness of the intermediate control layer At the gate temperature Within this range, there are also multiple magnified intervals:

[0097] Monotonically increasing interval The effective heat flux amplification factor is 21.49;

[0098] Monotonically increasing interval The effective heat flux amplification factor is 1.09;

[0099] Monotonically decreasing interval The effective heat flux amplification factor is 4.65.

[0100] The comparison shows that the heat flux amplification factor of the main amplification range of the 200nm gate thickness device is significantly higher than that of the 50nm thickness device, and the amplification range is wider. It also does not have the gain oscillation problem of multiple small gain ranges and has better working stability.

[0101] 2. Mode splitting and coupling mechanism of surface phonon polaritons

[0102] The heat flux modulation and amplification effect of the device in this invention originates from the mode coupling and decoupling process of surface phonon polaritons (SPhPs). SPhPs are electromagnetic surface modes in polar crystalline materials. When two polar material films are separated by a subwavelength distance, SPhPs couple within and between the films, resulting in a previously singular resonant frequency. The split occurs, forming two different resonance modes: a symmetric mode and a resonant mode. and antisymmetric mode This refers to the pattern splitting phenomenon.

[0103] The resonant frequencies of the symmetric and antisymmetric modes formed by mode splitting can be calculated using the following formula:

[0104] ;

[0105] In the formula, Simplified parameters for a single-plate system, For parallel wave vectors, The thickness of the intermediate control layer.

[0106] When the thickness of the intermediate control layer is small, the frequency difference between the symmetric mode and the antisymmetric mode is significant; as the thickness increases, the SPhPs on the upper and lower surfaces of the film gradually decouple, the split mode tends to disappear, and the frequencies of the two modes gradually approach each other.

[0107] Please see Figure 3 In (b), (c), and (d), regarding The intermediate control layer demonstrates the mode at gate temperatures of 300K, 325K, and 350K. Energy transfer efficiency distribution:

[0108] ①When ( Figure 3 (b) and ( Figure 3 In the middle (d) case, due to the larger gate thickness, the mode splitting phenomenon is not obvious, and the symmetrical mode is... With antisymmetric mode The frequencies almost overlapped, and no obvious mode coupling effect was observed.

[0109] ②When ( Figure 3 In the middle (c) stage, the strong coupling effect between modes begins to appear, and the system goes through the process of "decoupling-strong coupling-decoupling". At this time, the radiation coupling efficiency is significantly improved, and the corresponding peak region of the heat flux curve is significantly amplified.

[0110] Please see Figure 4 (b), (c), (d), (e), targeting The intermediate control layer is shown to display the mode energy transfer efficiency distribution at gate temperatures of 300K, 322K, 330K, and 350K:

[0111] ①When ( Figure 4 In (b)), the symmetrical pattern of splitting Antisymmetric mode It is not coupled with the system's inherent mode, resulting in low radiative transfer efficiency;

[0112] ②When ( Figure 4 In (c) the symmetric mode is strongly coupled with the system's intrinsic mode, causing the drain heat flux to form its first peak at that temperature;

[0113] ③When ( Figure 4 In the middle (d) time, the symmetric mode is decoupled, and the antisymmetric mode is strongly coupled with the system's inherent mode, resulting in a second peak in the drain heat flux;

[0114] ④ When ( Figure 4 In the case of (e), the antisymmetric mode is completely decoupled, and the radiative transfer efficiency drops.

[0115] It can be seen that a thinner gate thickness will produce obvious mode splitting, resulting in multiple peaks in the heat flow curve, obvious gain oscillation, and poor operating stability; while the preferred thickness of 200nm can effectively suppress mode splitting, highly concentrate spectral energy in a single high gradient transmission channel, and significantly improve the operating stability of the device while ensuring high amplification gain.

[0116] Example 5: Optimization Design and Performance Influence of Intermediate Control Layer Thickness

[0117] This embodiment analyzes in detail the influence of the thickness of the intermediate control layer on the amplification performance of the device, determines the optimal geometric dimensions of the device, and provides guidance for device design.

[0118] Please see Figure 5 In this embodiment, in a fixed , , Under these conditions, simulation calculations were performed on devices with different intermediate control layer thicknesses in the range of 50nm to 500nm to obtain the correspondence between thickness and thermal flux amplification factor. The size of the circle in the figure represents the operating temperature range corresponding to the amplification factor.

[0119] Simulation results show that the thickness of the intermediate modulation layer has a decisive influence on the amplification performance of the device, and the specific rules are as follows:

[0120] 1. When the thickness of the intermediate control layer At that time, the strong coupling of SPhPs on the upper and lower surfaces of the thin film induces a significant mode splitting phenomenon. The amplification efficiency of the device first increases and then decreases with the increase of thickness, and the amplification range is narrow. There are multiple gain oscillations and poor working stability.

[0121] 2. When the thickness of the intermediate control layer At that time, the mode splitting phenomenon was gradually suppressed, and the thermal flux amplification efficiency of the device increased significantly with the increase of thickness;

[0122] 3. When the thickness of the intermediate control layer At that time, mode splitting was significantly suppressed, radiation coupling efficiency reached its peak, and heat flux amplification factor reached its maximum value of 118.44, which is a relatively optimal geometric scale for the device.

[0123] 4. When the thickness of the intermediate control layer At that time, the thermal amplification efficiency of the device slows down and gradually approaches the threshold. Moreover, an excessively thick gate will increase the manufacturing cost and thermal response time, which is not conducive to the engineering application of the device.

[0124] Based on the above principles, the thickness of the intermediate control layer in this invention is preferably 80nm~200nm, with a preferred thickness of 200nm. This design can effectively suppress multimodal interference and improve radiation coupling efficiency, while also taking into account the feasibility of device fabrication and thermal response speed. It solves the problems of mode splitting, gain oscillation, and poor stability caused by simply pursuing ultra-thin gates in the prior art.

[0125] Example 6: Practical Device Examples and Performance Verification Based on Indium Antimonide (InSb) Material

[0126] This embodiment uses the actual narrow bandgap semiconductor material InSb as the intermediate modulation layer for device simulation verification, demonstrating the practical feasibility and excellent performance of the technical solution of this invention. InSb is only a specific material embodiment used to verify the feasibility of this invention and does not constitute a limitation on the material of the intermediate modulation layer; for other narrow bandgap semiconductor materials that satisfy the above-mentioned temperature-driven continuous frequency shift mechanism, the corresponding material parameters can also be substituted into the above model for device design and performance analysis.

[0127] The device structure and simulation conditions for this embodiment are as follows:

[0128] Both the first radiator (source) and the second radiator (drain) are made of SiO2 polar crystal material, and both have a thickness of 100 nm.

[0129] The intermediate control layer (gate) is made of InSb narrow bandgap semiconductor material with a thickness of 100nm;

[0130] Vacuum gap distance between source and gate, and between gate and drain ;

[0131] Source temperature Drain temperature Gate temperature The control range is 440K~530K.

[0132] Please see Figure 6 Simulation results show that the practical near-field heat flux control device based on InSb material exhibits excellent heat flux amplification performance over a wide temperature range:

[0133] 1. When the gate temperature At that time, the effective heat flux amplification factor of the device is as high as 22.19, and the continuous operating bandwidth is about 40K, which meets the performance requirement of the present invention that the heat flux amplification factor is greater than 20 in the temperature variation range of 30K~50K.

[0134] 2. When the gate temperature At that time, the device still maintains a stable heat flux amplification capability, with an effective heat flux amplification factor of 7.63.

[0135] This result demonstrates that the present invention, employing InSb narrow bandgap semiconductor as the intermediate modulation layer and utilizing its characteristic of smooth carrier concentration change with temperature, drives a continuous blue shift of the plasma frequency, inducing a "spectral sweep" effect between the emitter and receiver. This successfully achieves wide-temperature-range, high-gain near-field heat flux modulation, with a continuous and stable operating bandwidth reaching 40K, which is superior to existing methods. This invention achieves more than four times the efficiency of phase change material-based devices (typically less than 10K), effectively overcoming the inherent thermal hysteresis and gain oscillation problems of phase change materials, and realizing the expected technical effect of the invention.

[0136] Since the Drud model can be regarded as a degenerate form of the Lorentz model under certain conditions, the aforementioned theoretical analysis, mechanism explanation and design method for idealized temperature shift materials can be applied to actual devices based on InSb materials, providing theoretical support for further optimization and engineering applications of the devices.

[0137] Example 7: Detailed Implementation of the Near-Field Heat Flow Control Method

[0138] This embodiment provides a near-field heat flux control method, which is applied to a near-field thermal radiation system including a first radiator and a second radiator, and specifically includes the following steps:

[0139] Step S1: Construct a near-field thermal radiation system: An intermediate modulation layer made of a narrow bandgap semiconductor material is disposed between the first radiator and the second radiator, such that the first radiator, the intermediate modulation layer, and the second radiator are parallel to each other and coaxially arranged. Subwavelength scale vacuum gaps are respectively disposed between the first radiator and the intermediate modulation layer, and between the intermediate modulation layer and the second radiator; the temperature of the first radiator is maintained at a first temperature. The temperature of the second radiator is maintained at the second temperature. And satisfy ;

[0140] Step S2: Establish the temperature-frequency shift control relationship: Based on the Drud-Lorentz dielectric response model, establish the corresponding relationship between the dielectric properties of the intermediate control layer and temperature changes, and adjust the temperature of the intermediate control layer accordingly. This drives a smooth change in the carrier concentration of the intermediate control layer, thereby causing a continuous frequency shift in its plasma frequency. This forms a continuously changing radiative coupling between the first radiator and the second radiator, enabling continuous control of the near-field radiative heat flux.

[0141] Step S3, Quantitative evaluation of device performance: Calculate the effective heat flux amplification factor of the device based on the heat flux difference in monotonic intervals. The formula for calculating the heat flux amplification factor is as follows: ,in This represents the difference in heat flux received by the second radiator within the monotonic interval. The difference in net heat flux of the intermediate control layer at the corresponding temperature is used to evaluate the actual amplification performance of the device over a wide temperature range.

[0142] Step S4, Active heat flow control: The temperature of the intermediate control layer is controlled by an external heating / cooling unit. This allows it to reach the target steady-state temperature, at which point the net heat flow of the intermediate control layer... By changing By adjusting the radiation coupling efficiency of the system, the amplification or suppression of the near-field radiative heat flow between the first and second radiators can be achieved.

[0143] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A near-field heat flux control device, comprising a first radiator and a second radiator, characterized in that, It also includes an intermediate control layer independently disposed between the first radiator and the second radiator, wherein subwavelength scale vacuum gaps are respectively provided between the first radiator and the intermediate control layer and between the intermediate control layer and the second radiator; The intermediate control layer is made of a narrow bandgap semiconductor material. The carrier concentration of the narrow bandgap semiconductor material changes smoothly with temperature, so that the dielectric response characteristics of the intermediate control layer change continuously with temperature and drive the plasma frequency to shift, thereby continuously adjusting the radiation coupling between the first radiator and the second radiator to amplify or suppress the heat flow. The narrow bandgap semiconductor material is indium antimonide; The dielectric response characteristics of the intermediate control layer are described by the Drud-Lorentz model, and a temperature-dependent parameter that varies continuously with the temperature of the intermediate control layer is introduced to drive a continuous frequency shift in the plasma: ； In the formula, The dielectric function is... The dielectric constant is at infinite frequency. The longitudinal optical phonon frequency. This refers to the transverse optical phonon frequency. The attenuation coefficient is... Let be the angular frequency of the incident electromagnetic wave. The imaginary unit, For temperature-dependent parameters, the expression is: ； In the formula, This is the upper limit of the frequency offset. This represents the lower limit of the frequency offset. The temperature of the intermediate control layer, This represents the upper limit of the temperature. This represents the lower limit of the temperature. It is a regulating factor used to dynamically control the rate of change of frequency with temperature.

2. The near-field heat flux control device according to claim 1, characterized in that, The thickness of the intermediate control layer is 80nm to 200nm.

3. The near-field heat flux control device according to claim 1, characterized in that, The first radiator and the second radiator are made of polar crystalline materials.

4. The near-field heat flux control device according to claim 3, characterized in that, The polar crystal material is silicon dioxide or silicon carbide.

5. The near-field heat flux control device according to claim 1, characterized in that, The distance of the vacuum gap is 10 nm to 1 μm.

6. The near-field heat flux control device according to claim 1, characterized in that, When the material of the intermediate control layer is indium antimonide, the materials of the first radiator and the second radiator are silicon dioxide, and the device meets the preset structural parameters, the heat flux amplification factor of the device is greater than 20 when the temperature of the intermediate control layer varies from 30K to 50K.

7. A near-field heat flux control method, characterized in that, The method employs the near-field heat flux control device according to any one of claims 1 to 6, and includes the following steps: setting an intermediate control layer made of a narrow bandgap semiconductor material between the first radiator and the second radiator; driving the plasma frequency of the intermediate control layer to shift by controlling the temperature of the intermediate control layer, thereby forming a radiation coupling with continuously changing frequency between the first radiator and the second radiator; and realizing the amplification or suppression control of near-field radiative heat flux.

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