CN114050198B - A radiation heat flux control device based on semiconductor materials and its application - Google Patents

Abstract

The present invention relates to a radiation heat flux control device based on semiconductor materials and its application, which comprises a first radiator and a second radiator arranged relatively to each other, wherein the first radiator is provided with a semiconductor material layer, wherein the semiconductor material layer contains one or both of an intrinsic semiconductor material and a doped semiconductor material with a carrier doping concentration less than 10 ¹⁶ cm ^‑3 ; the first radiator is arranged in a suspended manner, or the first radiator comprises a first substrate containing a metal material layer. The technical solution of the present invention mainly utilizes the change of the local electromagnetic state density caused by the change of the carrier concentration inside the semiconductor material with the temperature to realize the large-scale control of the radiation heat flux. The radiation heat flux control device provided by the present invention can realize the functions of a thermal diode, a thermal triode, a thermal switch, etc. by changing the trigger mechanism or by combining with other components.

Description

A radiation heat flux control device based on semiconductor materials and its application

Technical Field

The present invention relates to the field of thermal radiation technology, and in particular to a radiation heat flux regulating device based on semiconductor materials and applications thereof.

Background technique

Heat transfer is one of the most basic physical phenomena in nature, and it is widely present in scientific research and production life. More than 90% of global energy production is related to heat. Therefore, effective regulation of the heat transfer process is crucial for the development of new thermal devices, advanced thermal management technologies, and improving energy efficiency. People's daily lives are closely related to heat, from dressing to keep warm, boiling water and cooking, to indoor temperature control and air conditioning in cars, covering all aspects of clothing, food, housing, and transportation. The continuous development of heat transfer regulation technology is expected to further improve people's living standards.

Nonlinear electrical components can achieve flexible control of electric current, which is the cornerstone of modern electronic information technology and has completely changed people's lives. However, in comparison, the control of heat flow is much more difficult. The research on nonlinear thermal devices that can flexibly control heat flow is not yet mature. The research on heat transfer mechanism and the effective control of heat transfer process are of great significance to scientific research and technological applications in the field of thermal science.

Thermal radiation is one of the three basic heat transfer mechanisms. Its essence is the electromagnetic waves caused by the random thermal motion of charges inside an object, including propagating waves and evanescent waves. According to the propagation characteristics of these electromagnetic waves, they can be divided into propagation mode, frustration mode and surface mode electromagnetic waves. Among them, the amplitude of the evanescent wave decays exponentially with the distance from the surface of the object. When the distance between the radiators is close to or less than the thermal characteristic wavelength, the evanescent wave begins to gradually participate in or even dominate the radiation heat transfer, and the classical law of thermal radiation is broken. This phenomenon is called near-field thermal radiation.

Thermal flux control devices based on near-field thermal radiation often have two ends, namely, radiators on both sides, and the heat flux is transmitted between the two radiators in the form of electromagnetic waves. Thermal rectification based on near-field thermal radiation is expected to achieve greater control capabilities because it can use richer electromagnetic modes to control heat flux. It has received widespread attention in various nonlinear thermal devices such as thermal diodes, thermal triodes, and thermal switches.

The physical mechanisms behind different nonlinear thermal devices such as thermal diodes, thermal triodes and thermal switches are relatively similar. In near-field thermal radiation, they can be summarized as follows: through different triggering mechanisms such as heat, light, and electricity, different electromagnetic waves in near-field thermal radiation are regulated, thereby achieving the purpose of changing the size of the radiation heat flux. Take the thermal diode as an example - the thermal diode based on the thermal rectification effect is a very typical way of heat flow regulation. Under the same temperature difference, the size of the heat flow in the thermal rectification device is related to the bias direction of the temperature. When the temperature direction changes, the change in the dielectric constant will cause a difference in the radiation heat flow, thereby forming thermal rectification. The core performance parameter of thermal rectification is the rectification ratio, which is defined as the ratio of the difference between the forward and reverse heat flows to the smaller reverse heat flow.

In summary, in order to better achieve regulation during heat transport, technical personnel in this field hope to develop a new technical solution to effectively improve the heat flow regulation capability of near-field radiation heat flow regulation devices.

Summary of the invention

The purpose of the present invention is to provide a radiation heat flux control device based on semiconductor materials and its application, which mainly utilizes the change of local electromagnetic state density caused by the change of carrier concentration inside the semiconductor material with temperature to achieve a large-scale control of radiation heat flux. The radiation heat flux control device can realize functions such as thermal rectification, thermal triode, thermal switch, etc. by changing the trigger mechanism or combining with other components.

To this end, in a first aspect, the present invention provides a radiation heat flux regulating device based on semiconductor materials, which comprises a first radiator and a second radiator arranged opposite to each other;

The first radiator is provided with a semiconductor material layer, and the semiconductor material layer contains one or both of an intrinsic semiconductor material and a doped semiconductor material having a carrier doping concentration less than 10 ¹⁶ cm ^-3 ;

The first radiator is arranged in one of the following ways:

(a) the first radiator is composed of the semiconductor material layer, and the first radiator is suspended in the air;

(b) the first radiator further includes a first substrate, the first substrate is made of a non-metallic material, the semiconductor material layer covers the first substrate, and the first radiator is suspended;

(c) The first radiator further includes a first substrate, the first substrate includes a first metal material layer, and the semiconductor material layer covers the first substrate.

Further, the spacing between the first radiator and the second radiator is 1nm-10mm, preferably 10nm-100μm, and more preferably 10nm-1μm. For example, the spacing between the first radiator and the second radiator is 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, etc.

Furthermore, in the semiconductor material layer, the volume proportion of semiconductor material is 30%-100% (V/V); preferably, the semiconductor material exists in the form of regularly or irregularly distributed discrete components, or the semiconductor material layer contains regularly or irregularly distributed non-semiconductor material components.

In some embodiments, the semiconductor material layer is composed of one or both of an intrinsic semiconductor material and a doped semiconductor material having a carrier doping concentration less than 10 ¹⁶ cm ⁻³ .

In some embodiments, in the semiconductor material layer, the volume proportion of semiconductor material is greater than or equal to 30% and less than 100%; preferably, the semiconductor material exists in the form of regularly or irregularly distributed discrete components, or the semiconductor material layer contains regularly or irregularly distributed non-semiconductor material components.

Further, in the semiconductor material layer, the semiconductor is selected from one or a combination of two or more of the following groups: silicon (Si), germanium (Ge), gallium phosphide (GaP), gallium arsenide (GaAs), indium arsenide (InAs), boron (B), tellurium (Te), selenium (Se), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), silicon carbide (SiC), zinc oxide (ZnO), silicon nitride (Si ₃ N ₄ ), gallium antimonide (GaSb), zinc sulfide (ZnS), cadmium telluride (CdTe), mercury telluride (HgTe), cuprous bromide (CuBr), cuprous iodide (CuI), bismuth telluride (Bi ₂ Te ₃ ), bismuth selenide (Bi ₂ Se ₃ ), bismuth sulfide (Bi ₂ S ₃ ), arsenic telluride (As ₂ Te ₃ ); preferably silicon (Si), germanium (Ge), gallium phosphide (GaP), gallium arsenide (GaAs), indium arsenide (InAs), etc.

Further, the thickness of the semiconductor material layer is 1nm-100mm, preferably 1nm-1mm, and more preferably 1nm-100μm; for example, 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.

According to the radiation heat flux control device provided by the present invention, when the temperature changes, the carrier concentration of the semiconductor material layer in the first radiator will change dramatically, thereby causing the intensity of the high κ mode in the low-frequency range to change sharply, which is the key element for the radiation heat flux control device of the present invention to achieve excellent thermal rectification performance. The intensity of the low κ mode in the high-frequency range hardly changes with temperature, because these electromagnetic modes are mainly affected by the real part of the dielectric constant ε′ of the semiconductor material layer, and ε′ hardly changes with temperature, so these low κ modes have a great negative impact on the performance of thermal rectification. Preferably, when the thickness of the semiconductor material layer is 1nm-1mm, these low κ modes are significantly weakened, while the high κ mode in the low-frequency range is almost unaffected, so that the thermal rectification performance of the radiation heat flux control device can be significantly improved.

Further, the thickness of the first substrate is 1nm-100mm, for example, 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.

In some embodiments, the first radiator includes a semiconductor material layer and a first substrate composed of a non-metallic material, and the thickness of the first substrate is 1nm-1μm, for example, 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, etc.

Furthermore, the non-metallic material is preferably a polar material.

In some embodiments, the first radiator includes a semiconductor material layer and a first substrate, the semiconductor material layer is covered on the first substrate, and the first substrate contains a first metal material layer; in the first metal material layer, the volume proportion of the metal material is 20% (V/V) or more; preferably, the thickness of the first metal material layer is 1nm-100mm, for example, 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.;

Preferably, the distance between the midpoint of the vertical line between the first radiator and the second radiator and the first metal material layer is 10nm-100mm; for example, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.

In some embodiments, the first metal material layer is made of metal material.

In some embodiments, the first substrate is composed of a first metal material layer.

In some other embodiments, the first substrate includes a first metal material layer and a non-metal material layer; the non-metal material is preferably a polar material.

Furthermore, the second radiator is provided with one or a combination of a polar material layer and a doped semiconductor material layer.

Furthermore, in the polar material layer, the volume proportion of polar material is 30%-100% (V/V); preferably, the polar material exists in the form of regularly or irregularly distributed discrete components, or the polar material layer contains regularly or irregularly distributed non-polar material components.

In some embodiments, the polar material layer is made of polar material.

In some embodiments, in the polar material layer, the volume proportion of polar material is greater than or equal to 30% and less than 100%; preferably, the polar material exists in the form of regularly or irregularly distributed discrete components, or the polar material layer contains regularly or irregularly distributed non-polar material components.

Further, the polar material is selected from sodium chloride (NaCl), potassium bromide (KBr), potassium chloride (KCl), barium fluoride (BaF ₂ ), cesium fluoride (SrF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), gallium nitride (GaN), magnesium oxide (MgO), cesium bromide (CsBr), cesium iodide (CsI), zinc sulfide (ZnS), silver bromide (AgBr), silver chloride (AgCl), cubic boron nitride (cBN), silicon carbide (SiC), silicon dioxide (SiO ₂ ), hexagonal boron nitride (hBN), zinc selenide (ZnSe), sapphire, cadmium telluride (CdTe), silicon dioxide (SiO ₂ ), etc.; preferably sodium chloride (NaCl), potassium bromide (KBr), potassium chloride (KCl), barium fluoride (BaF ₂ ), cesium fluoride (SrF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), gallium nitride (GaN), magnesium oxide (MgO), cesium bromide (CsBr), cesium iodide (CsI), zinc sulfide (ZnS), silver bromide (AgBr) or silver chloride (AgCl).

Further, the thickness of the polar material layer is 1nm-100mm, preferably 1nm-10mm; for example, 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.

Further, the doped semiconductor layer is composed of a doped semiconductor material with a carrier doping concentration greater than 10 ¹⁵ cm ^-3 ; preferably, the doping concentration is 10 ¹⁵ -10 ²⁰ cm ^-3 ; more preferably, the doping concentration is 10 ¹⁶ -10 ²⁰ cm ^-3 ; further preferably, the doping concentration is 10 ¹⁷ -10 ¹⁹ cm ^-3 ; wherein the semiconductor is selected from silicon (Si), germanium (Ge), gallium phosphide (GaP), gallium arsenide (GaAs), indium arsenide (InAs), boron (B), tellurium (Te), selenium (Se), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), silicon carbide (SiC), zinc oxide (ZnO), silicon nitride (Si ₃ N ₄ ), gallium antimonide (GaSb), zinc sulfide (ZnS), cadmium telluride (CdTe), mercury telluride (HgTe), cuprous bromide (CuBr), cuprous iodide (CuI), bismuth telluride (Bi ₂ Te ₃ ), bismuth selenide (Bi ₂ Se ₃ ), bismuth sulfide (Bi ₂ S ₃ ), arsenic telluride (As ₂ Te ₃ ); preferably silicon (Si), germanium (Ge), gallium phosphide (GaP), gallium arsenide (GaAs) or indium arsenide (InAs).

The thickness of the doped semiconductor layer is 1nm-100mm, preferably 1nm-10mm; for example, 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.

Furthermore, the second radiator further comprises a second substrate, the polar material layer or the doped semiconductor material layer covers the second substrate, and the second substrate comprises a metal material layer; in the metal material layer, the volume proportion of the metal material is greater than 20% (V/V);

Preferably, the thickness of the second metal material layer is 1nm-100mm, for example, 1nm, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.;

Preferably, the distance between the midpoint of the vertical line between the first radiator and the second radiator and the second metal material layer is 10nm-100mm, for example, 10nm, 20nm, 50nm, 80nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 100μm, 500μm, 1mm, 2mm, 5mm, 10mm, 50mm, 100mm, etc.

According to the radiation heat flux control device described in the present invention, when it includes a substrate containing a metal material layer, the distance between the midpoint of the vertical line between the first radiator and the second radiator and the metal material layer is 10nm-100mm. The present invention has found in research that if the metal material layer is too close (for example, less than 10nm), it will contribute more radiation heat flux, and these heat fluxes are not sensitive to changes in the temperature bias direction (because the dielectric constant of the metal is not sensitive to temperature changes), so it will weaken the heat flux control performance; if the metal material layer is too far (for example, greater than 100mm), it means that there is a larger volume of radiators above the metal layer, resulting in more low-κ modes, which will also weaken the heat flux control performance.

In some embodiments, the second metal material layer is made of a metal material.

In some embodiments, the second substrate is composed of a second metal material layer.

In some other embodiments, the second substrate includes a second metal material layer and a non-metal material layer; the non-metal material is preferably a polar material.

Furthermore, the metal material is selected from one or a combination of two or more of the following: silver (Ag), gold (Au) and aluminum (Al).

According to the radiation heat flux control device described in the present invention, the main functions of the first substrate and the second substrate are to support and enhance the mechanical strength of the device, and the metal material layer is mainly used to shield the thermal radiation on the back of the device. When the thickness of the metal material layer is greater than or equal to 10nm, effective shielding can be achieved; when the thickness of the metal material layer is greater than or equal to 100nm, more efficient shielding can be achieved; when the thickness of the metal material layer is greater than or equal to 1000nm, nearly complete shielding can be achieved. At this time, placing the radiation heat flux control device on any object will not affect the heat flux control performance of the device. Even if the thickness of the metal material layer is only 1nm, it can still have a certain shielding effect. The thickness of the appropriate metal material layer can be selected between 10nm-100mm according to actual conditions, and common thicknesses are, for example, 100nm-10μm.

In some embodiments, the second radiator includes a doped semiconductor material layer, a polar material layer, and a second substrate stacked in sequence.

According to the radiation heat flux regulation device of the present invention, if a covering layer with a thickness not exceeding 1 μm is added on the surface of the second radiator on the side close to the first radiator (for example, a covering layer with pores or a non-metallic material accounting for more than 20% is added); and/or, if a covering layer with a thickness not exceeding 1 μm is added on the surface of the first radiator on the side close to the second radiator (for example, a covering layer with pores or a non-metallic material accounting for more than 20% is added), it is still within the protection scope of the present invention.

The radiation heat flux regulating device according to the present invention comprises at least a first radiator and a second radiator. On this basis, the radiation heat flux regulating device can be provided with more radiators by stacking a plurality of first radiators and second radiators, which is also within the protection scope of the present invention.

In some embodiments, in the radiation heat flux regulating device, one or more radiators are further arranged between the first radiator and the second radiator.

In some embodiments, in the radiation heat flux regulating device, one or more first radiators and/or second radiators are further arranged between the first radiator and the second radiator.

A second aspect of the present invention provides application of the radiation heat flux regulating device of the present invention in heat flux regulation.

According to a third aspect of the present invention, a heat flux regulator is provided, which includes the radiation heat flux regulating device.

Furthermore, the heat flux regulator is a thermal diode, a thermal triode or a thermal switch.

Compared with the prior art, the present invention has the following advantages:

The present invention provides a radiation heat flux regulation device comprising a first radiator and a second radiator, wherein the first radiator contains a semiconductor material layer, so that it can provide the largest possible local electromagnetic state density difference; the second radiator contains a polar material layer and/or a doped semiconductor material layer, so that it can selectively screen a suitable frequency band to dominate the radiation heat exchange, so that the largest possible local electromagnetic state density difference provided by the first radiator can be converted into a radiation heat flux difference, thereby realizing efficient regulation of the radiation heat flux.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other advantages and benefits will become apparent to those skilled in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings:

Figure 1: Schematic diagram of the principle of a thermal diode based on thermal radiation;

Figure 2: Variation of the real and imaginary parts of the dielectric constant of intrinsic silicon at different temperatures;

Figure 3: Local electromagnetic state density of intrinsic silicon in a semi-infinite planar structure at different temperatures;

Figure 4: Change ratio of local electromagnetic state density of intrinsic silicon layered materials of different thicknesses; where local electromagnetic state density change ratio = local electromagnetic state density at 1000K/local electromagnetic state density at 300K;

Figure 5: The change ratio of the local electromagnetic state density of the intrinsic silicon void film and the local electromagnetic state density of the infinite planar structure polar material layer; where the change ratio of the local electromagnetic state density = the local electromagnetic state density at 1000K/the local electromagnetic state density at 300K;

Figure 6: The change ratio of the local electromagnetic state density of the intrinsic silicon empty film and the local electromagnetic state density of doped silicon films of different thicknesses at 300K and 1000K respectively; where the change ratio of the local electromagnetic state density = the local electromagnetic state density at 1000K/the local electromagnetic state density at 300K;

FIG7 is a schematic structural diagram of a first radiator of a radiant heat flux regulating device provided by the present invention;

FIG8 is a schematic structural diagram of a second radiator of the radiation heat flux regulating device provided by the present invention;

FIG9 is another schematic diagram of the structure of the second radiator of the radiation heat flux regulating device provided by the present invention;

FIG10 is a schematic diagram of the structure of a thermal diode provided by the present invention;

FIG11 is a schematic diagram of the structure of a thermal triode provided by the present invention;

FIG12 : Changes in the rectification ratio of the thermal diode provided by the present invention under different radiator spacing conditions;

FIG13 is a diagram showing the local electromagnetic state density of a first radiator made of intrinsic silicon under temperature variation;

FIG14 : Change ratio of local electromagnetic state density of the first radiator composed of intrinsic silicon and silver; wherein, change ratio of local electromagnetic state density=local electromagnetic state density at 1000K/local electromagnetic state density at 300K;

Figure 15: Radiative heat transfer coefficient diagram of a thermal diode composed of intrinsic silicon and potassium bromide under forward and reverse temperature bias conditions;

Figure 16: The rectification ratio of the thermal diode of the combination of intrinsic silicon and potassium bromide varies with film thickness;

Figure 17: Radiative heat transfer coefficient diagram of a thermal diode composed of intrinsic silicon and doped silicon under forward and reverse temperature bias conditions;

Figure 18: The rectification ratio of the thermal diode of the combination of intrinsic silicon and doped silicon varies with film thickness;

FIG. 19 : Schematic diagram of the structure of a thermal diode comprising a combination of intrinsic silicon and potassium bromide on a substrate;

Figure 20: Variation of the rectification ratio of a thermal diode composed of intrinsic silicon and potassium bromide with film thickness;

FIG. 21 : Schematic diagram of the structure of a thermal diode comprising a combination of intrinsic silicon and doped silicon on a substrate;

Figure 22: Variation of the rectification ratio of a thermal diode composed of intrinsic silicon and doped silicon with film thickness;

FIG23 : Schematic diagram of the structure of a thermal diode comprising a substrate of intrinsic silicon, doped silicon and potassium bromide;

Figure 24: Variation of the rectification ratio of a thermal diode with a combination of intrinsic silicon, doped silicon and potassium bromide containing a substrate with film thickness;

FIG. 25 : Schematic diagram of the structure of a thermal diode comprising a combination of intrinsic silicon and cubic boron nitride with a non-metallic substrate.

Detailed ways

The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

Figure 1 shows a schematic diagram of the principle of a thermal diode based on thermal radiation, which is a very typical way of regulating heat flow. Under the same temperature difference, the heat flow in the thermal rectifier device is related to the bias direction of the temperature. When the temperature direction changes, the change in the dielectric constant will cause a difference in the radiation heat flow, thus forming thermal rectification. The core performance parameter of thermal rectification is the rectification ratio, which is defined as the ratio of the difference between the forward and reverse heat flows to the smaller reverse heat flow.

Based on the wave electrodynamics theory framework, the radiation heat flow between two parallel plane radiators, the first radiator (at temperature _T1 ) and the second radiator (at temperature _T2 ), can be calculated by the following formula:

Where d is the distance between the two radiators, ω is the angular frequency, and κ is the transverse wave vector. For far-field thermal radiation at a macroscopic scale, only electromagnetic waves with a transverse wave vector less than ω/c ₀ participate in radiative heat transfer (c ₀ is the speed of light in a vacuum); when the distance between the two radiators is less than the thermal wavelength (about 10 μm at room temperature), evanescent waves with a transverse wave vector κ greater than ω/c ₀ begin to participate in or even dominate radiative heat transfer, especially when some electromagnetic modes with large transverse wave vectors κ (called high-κ electromagnetic modes) participate, the radiative heat transfer capacity can be enhanced by several orders of magnitude compared to far-field thermal radiation. Therefore, by rationally utilizing these high-κ modes, it is expected to achieve efficient regulation of radiative heat flux.

The present invention enables the near-field radiation heat flux control device to have the greatest possible heat flux control capability by enabling the first radiator to provide the greatest possible difference in local electromagnetic state density. In addition, since the difference in local electromagnetic state density in different frequency bands is different, the present invention uses the second radiator to selectively select a suitable frequency band to dominate the radiation heat exchange, so that the greatest possible difference in local electromagnetic state density provided by the first radiator can be converted into a difference in radiation heat flux, thereby achieving efficient control of radiation heat flux.

The local electromagnetic state density is defined as the number of electromagnetic modes per unit space and per unit frequency in a certain area above the radiator. For a planar radiator, the local electromagnetic state density at position z above it can be calculated using the following formula:

In formula (2), _rs and _rp are the interface Fresnel reflection coefficients of s and p polarization states, respectively, and _k0 and _γ0 are the transverse wave vector and longitudinal wave vector (perpendicular to the interface) in vacuum, respectively. The reason why the local electromagnetic state density is selected as the reference physical quantity is that the local electromagnetic state density can reflect the near-field radiation capability of a radiator. Generally speaking, the larger the local electromagnetic state density of a radiator, the greater the near-field radiation heat flux it can achieve.

From the above, it can be seen that a key to achieving efficient thermal radiation regulation is to design a radiator so that it can achieve a large change in local electromagnetic state density under the control of the external environment (such as temperature, electric field, magnetic field, pressure, etc.). In order to obtain the largest possible change in local electromagnetic state density, the present invention uses layered semiconductor materials to induce a large difference in local electromagnetic state density by utilizing the change in dielectric constant caused by the change in internal carriers. For semiconductor materials, their dielectric constant can generally be written as the following expression:

Among them, ε′ and ε″ are the real and imaginary parts of the dielectric constant, ε _bl represents the contribution from the electron interband transition and lattice absorption inside the material, _Ne , τ _e is the concentration, equivalent mass and relaxation time of electrons in the conduction band, N _h ,/> τ _h is the concentration, equivalent mass and relaxation time of holes in the valence band, and ε ₀ is the vacuum dielectric constant.

Taking the dielectric constant characteristics of semiconductor materials at different temperatures as an example, when the temperature rises, the concentration of free carriers increases due to thermal excitation, resulting in a significant increase in the imaginary part of the dielectric constant ε″, while the real part of the dielectric constant ε′ remains almost unchanged. Taking intrinsic silicon as an example, Figure 2 shows the variation of the real and imaginary parts of its dielectric constant with temperature; Figure 3 shows the local electromagnetic state density characteristics of intrinsic silicon with a semi-infinite planar structure at different temperatures.

As shown in Figure 3, when the temperature of the semi-infinite planar structure intrinsic silicon increases from 300K to 1000K, the local electromagnetic state density in the low-frequency range can change by more than 4 orders of magnitude. The main reason is that the emissivity of the high-κ mode of the p-polarization state It increases with the increase of ε″, and it is the increase of these high-κ modes that causes the local electromagnetic state density above the radiator to rise sharply. So far, it can be known that temperature can cause an increase in the carrier concentration of the semiconductor, resulting in a characteristic change in its dielectric constant, and ultimately causing a significant difference in the local electromagnetic state density.

In order to further improve the difference in local electromagnetic state density of semiconductor layered materials at different temperatures, the present invention studies the local electromagnetic state density characteristics of semiconductor layered materials of different thicknesses. The present invention finds that by making the semiconductor material thin and suspended, the contribution of electromagnetic waves with a small transverse wave vector κ propagating inside the material to thermal radiation can be reduced, thereby obtaining a greater difference in local electromagnetic state density within a wider frequency range. Taking intrinsic silicon as an example, FIG4 shows the variation characteristics of the local electromagnetic state density of intrinsic silicon layered materials at different thicknesses.

In order to provide a first radiator with the largest possible change in local electromagnetic state density, in some embodiments of the present invention, the semiconductor material in the first radiator is intrinsic silicon; in other embodiments of the present invention, the semiconductor material in the first radiator is a low-doped semiconductor (carrier doping concentration is less than 10 ¹⁶ cm ^-3 ). When a low-doped semiconductor material is used, due to its low carrier concentration, changes in the external environment (such as temperature, electric field, magnetic field, pressure, etc.) are more likely to produce larger carrier concentration changes, thereby helping to achieve a larger difference in local electromagnetic state density and corresponding radiation heat flow control capabilities.

In order to fully utilize the difference in local electromagnetic state density constructed by the layered semiconductor material in the first radiator and convert it into a difference in radiation heat flow, the present invention provides a second radiator that matches the first radiator. In some embodiments of the present invention, the second radiator is a narrowband radiator, mainly composed of polar materials; in other embodiments of the present invention, the second radiator is a broadband radiator, mainly composed of doped semiconductor materials.

In some embodiments of the present invention, the second radiator is a narrow-band radiator, the main feature of which is that it can support a peak of the local electromagnetic state density within a narrow frequency band. In some embodiments, the second radiator comprises a polar material layer, and the polar material is selected from one or a combination of two or more of the following: sodium chloride (NaCl), potassium bromide (KBr), potassium chloride (KCl), barium fluoride (BaF ₂ ), cesium fluoride (SrF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), gallium nitride (GaN), magnesium oxide (MgO), cesium bromide (CsBr), cesium iodide (CsI), zinc sulfide (ZnS), silver bromide (AgBr), silver chloride (AgCl), cubic boron nitride (cBN), silicon carbide (SiC), silicon dioxide (SiO ₂ ), hexagonal boron nitride (hBN), zinc selenide (ZnSe), sapphire, cadmium telluride (CdTe), silicon dioxide (SiO ₂ ), etc.; preferably sodium chloride (NaCl), potassium bromide (KBr), potassium chloride (KCl), barium fluoride (BaF ₂ ), cesium fluoride (SrF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), gallium nitride (GaN), magnesium oxide (MgO), cesium bromide (CsBr), cesium iodide (CsI), zinc sulfide (ZnS), silver bromide (AgBr), silver chloride (AgCl).

The present invention provides the polar material that can be used for the second radiator. By using a suitable polar material, the frequency band with a large difference in local electromagnetic state density constructed by the semiconductor layered material can be screened out, thereby achieving effective regulation of the radiation heat flow.

As an example, FIG5 shows five different polar materials, namely potassium bromide (KBr), potassium chloride (KCl), barium fluoride ( _BaF2 ), silicon carbide (SiC) and cubic boron nitride (cBN), and shows the local electromagnetic state density characteristics of these five polar material layers with a semi-infinite planar structure; for the convenience of comparison and contrast, the change ratio of the local electromagnetic state density of the intrinsic silicon void film is also shown.

As shown in Figure 5, these five polar materials can form a very sharp local electromagnetic state density peak in a specific frequency band. When the difference in the local electromagnetic state density caused by the semiconductor layered material in the frequency band corresponding to these peaks is greater, the radiation heat flow control capability that can be formed is greater. Therefore, for intrinsic silicon thin film, these five materials can be matched with it to obtain a greater radiation heat flow control capability, among which potassium bromide is the best match with intrinsic silicon thin film.

In some embodiments of the present invention, the second radiator is a broadband radiator, which is mainly characterized by having a large local electromagnetic state density in a wide low-frequency range, and the local electromagnetic state density in the low-frequency region does not change significantly with changes in the external environment (such as temperature, electric field, magnetic field, pressure, etc.). In some embodiments, the second radiator includes a doped semiconductor material layer, and the carrier doping concentration of the doped semiconductor material is greater than 10 ¹⁵ cm ^-3 . Due to the high carrier concentration of the doped semiconductor material, the local electromagnetic state density is prone to change significantly with changes in the external environment.

As an example, FIG6 shows the local electromagnetic state density of doped silicon (n-type doping, doping concentration of 10 ¹⁸ cm ^-3 ) films of different thicknesses at 300K and 1000K respectively; for the convenience of comparison, the change ratio of the local electromagnetic state density of the intrinsic silicon void film is also shown.

As shown in Figure 6, semi-infinite planar structure doped silicon and doped silicon films of different thicknesses can support a large local electromagnetic state density in the low-frequency range, which makes it possible to fully utilize the large difference in local electromagnetic state density generated by semiconductor layered materials in the low-frequency range. At the same time, as the doped silicon film becomes thinner, its local electromagnetic state density in the high-frequency range continues to decrease. This means that thinning the doped silicon film can weaken electromagnetic waves with a small transverse wave vector κ propagating inside it, thereby allowing changes in high-κ electromagnetic modes to dominate changes in radiant heat flow and achieve more efficient heat flow regulation.

In one embodiment, referring to FIG. 7 , the first radiator is arranged in one of the following three ways:

(a) The first radiator is composed of a semiconductor material layer, and the first radiator is suspended;

(b) the first radiator comprises a semiconductor material layer and a first substrate, the first substrate is made of a non-metallic material, the semiconductor material layer covers the first substrate, and the first radiator is suspended;

(c) The first radiator includes a semiconductor material layer and a first substrate, wherein the first substrate includes a first metal material layer, and the semiconductor material layer covers the first substrate.

In one embodiment, referring to FIG8 , the second radiator is arranged in one of the following three ways:

(a) the second radiator is composed of a polar material layer, and the second radiator is suspended;

(b) the second radiator comprises a polar material layer and a second substrate, the second substrate is made of a non-metallic material, the polar material layer covers the second substrate, and the second radiator is suspended;

(c) The second radiator includes a polar material layer and a second substrate, the second substrate includes a first metal material layer, and the polar material layer covers the second substrate.

In one embodiment, referring to FIG. 9 , the second radiator is disposed in one of the following two ways:

(a) the second radiator is composed of a doped semiconductor material layer, and the second radiator is suspended;

(b) the second radiator comprises a doped semiconductor material layer and a second substrate, the second substrate is made of a non-metallic material, the doped semiconductor material layer covers the second substrate, and the second radiator is suspended;

(c) The second radiator includes a doped semiconductor material layer and a second substrate, wherein the second substrate includes a first metal material layer, and the doped semiconductor material layer covers the second substrate.

In the present invention, an important factor in achieving a large heat flux control performance is to weaken the contribution of the low κ mode propagating inside the radiator, and these low κ modes are related to the volume of the radiator. Generally speaking, the larger the volume of the radiator, the more low κ modes there are, and the worse the heat flux control performance. Therefore, the radiator used in the present invention is set in one of the following ways: one is to use a substrate containing a metal material layer. Since the metal material layer has a high reflectivity, it can shield the thermal radiation on the back of the radiator, that is, other materials on the back of the radiator cannot affect the radiation heat exchange, which is equivalent to the volume of the radiator that produces the low κ mode. The volume of the radiator above the metal layer can only be the volume of the radiator above the metal layer, thereby effectively limiting the number of low κ modes; and if a substrate containing a metal layer is not used, in order to avoid introducing too many low κ modes, the radiator cannot be too thick and needs to be suspended (that is, there can be no other radiators on the back of the radiator). Under the condition of the suspended setting, the radiator may not include a substrate, or may include a substrate composed of non-metallic materials such as polar materials. This setting method can also limit the contribution of low κ modes. In actual use, the suspended method can be a cantilever support method.

According to the present invention, when the semiconductor material layer covers the first substrate including the metal material layer, the first radiator may be suspended or non-suspended, both of which are within the protection scope of the present invention.

According to the present invention, the term "semiconductor material" includes intrinsic semiconductor materials and doped semiconductor materials, and is a general concept of the two.

In one embodiment, the semiconductor material layer is made of semiconductor material.

In one embodiment, in the semiconductor material layer, the volume percentage of the semiconductor material is 30%-100% (V/V), for example, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc.

In one embodiment, in the semiconductor material, when the proportion of the semiconductor material is less than 100%, the portion other than the semiconductor material is pores or non-metallic material (eg, polar material).

In some embodiments, the semiconductor material layer is not entirely composed of semiconductor materials. This may be because impurities are inevitably introduced during the device preparation process, or pores are set in the semiconductor material layer or filled with other non-semiconductor materials for cost considerations. These technical adjustments and improvements are within the scope of the present invention. For the technical solution of the present invention, when the volume proportion of the semiconductor material in the semiconductor material layer is ≥30%, it can make a greater contribution to the local electromagnetic state density of the first radiator, thereby having significantly excellent heat flow control performance.

The filling material can be a non-metallic material, especially a polar material. This is because metal materials will induce a wide spectrum of difficult-to-control surface plasmon polaritons, thereby weakening the change of the local electromagnetic state density, while polar materials only have difficult-to-control surface phonon polaritons in an extremely narrow frequency band, and will not have a large impact on the local electromagnetic state density in a wider frequency band. Therefore, the first radiator can still form a larger difference in the local electromagnetic state density.

In one embodiment, the polar material layer is made of polar material.

In one embodiment, in the polar material layer, the volume percentage of the polar material is 30%-100% (V/V); for example, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc.

In one embodiment, the first substrate or the second substrate contains not only a metal material layer but also a non-metal material layer.

In one embodiment, the first substrate or the second substrate comprises a plurality of metal material layers and non-metal material layers.

In one embodiment, referring to FIG. 10 , the radiation heat flux regulating device is a thermal diode, which includes a first radiator and a second radiator that are arranged opposite to each other.

In a certain embodiment, referring to FIG. 11 , the radiation heat flux regulating device is a radiation heat triode, which includes a first radiator and two second radiators, wherein the first radiator is sandwiched between the two second radiators.

In one embodiment, the radiation heat flux control device (denoted as i-Si-KBr in FIG. 12 ) includes a first radiator and a second radiator, wherein the first radiator is composed of an intrinsic silicon film with a thickness of 10 nm, and the second radiator is composed of a potassium bromide film with a thickness of 10 nm; in another embodiment, the radiation heat flux control device (denoted as i-Si-d-Si in FIG. 12 ) includes a first radiator and a second radiator, wherein the first radiator is composed of an intrinsic silicon film with a thickness of 10 nm, and the second radiator is composed of a doped silicon (doping concentration 10 ¹⁸ cm ^-3 ) film with a thickness of 10 nm. The change of the rectification ratio when the distance between the two radiators changes is calculated and analyzed, and the result is shown in FIG. 12 . According to FIG. 12 , when the distance between the two radiators is 1 μm, the rectification ratio of more than three orders of magnitude can still be achieved.

In the following, the radiation heat flux regulation device of the present invention is explained using a thermal diode as an example, but this does not limit the radiation heat flux regulation device of the present invention to be used only as a thermal diode. It can realize the functions of a thermal triode, a thermal switch, etc. by changing the trigger mechanism or combining with other components.

Example 1

This embodiment provides a first radiator composed of an intrinsic silicon material layer. The local electromagnetic state density at 100 nm above the first radiator is calculated and analyzed. The relevant parameters include: the high temperature end temperature is 1000K, the low temperature section temperature is 300K, and the analysis results are shown in FIG13 .

In Figure 13, (a) the intrinsic silicon material layer is a block material, which is equivalent to a semi-infinite plane in thermal radiation analysis; (d) the thickness of the intrinsic silicon material layer is 10nm; in the figures below (a) and (d), the local electromagnetic state density of the intrinsic silicon material layer under temperature changes is shown respectively. Each point in the figure corresponds to the local electromagnetic state density of a specific frequency and transverse wave vector. The brighter it is, the more electromagnetic modes there are in this mode.

In the radiation heat flux control device provided by the present invention, the key to achieving thermal rectification is that when the temperature bias direction changes, it will cause a drastic change in the carrier concentration in the semiconductor material layer of the first radiator, which will cause the intensity of the high κ mode in the low-frequency range to change sharply. As shown in Figure 13, the intensity of the low κ mode in the high-frequency range (the electromagnetic mode that can propagate inside the intrinsic silicon material) hardly changes with temperature, because these electromagnetic modes are mainly affected by the real part of the dielectric constant ε′ of the intrinsic silicon, and ε′ hardly changes with temperature, so these low κ modes have a great negative impact on the performance of thermal rectification. When the semi-infinite intrinsic silicon block is changed to a finite thickness intrinsic silicon film with a void, these low κ modes are significantly weakened, while the high κ mode in the low-frequency range is almost unaffected, which significantly improves the thermal rectification performance.

Example 2

This embodiment provides a first radiator composed of an intrinsic silicon material layer and a first substrate, wherein the first substrate is composed of silver. The local electromagnetic state density at 10nm and 100nm above the first radiator is calculated and analyzed, and the relevant parameters include: the high temperature end temperature is 1000K, and the low temperature section temperature is 300K. The analysis results are shown in FIG14 .

Although a suspended film structure can be realized (for example, by cantilever support, etc.), in order to facilitate processing and assembly, this embodiment provides a first radiator with a substrate. In order to shield the influence of back radiation and improve the mechanical strength of the device, this embodiment sets a metal substrate with high reflectivity under the intrinsic silicon film. As can be seen from Figure 14, when a bulk (equivalent to a semi-infinite planar structure) silver substrate is added, a large difference in local electromagnetic state density can still be formed in the low-frequency range at a suitable intrinsic silicon film thickness.

The present invention finds through calculation and analysis that the metal layer in the substrate will also contribute to the local electromagnetic state density above the radiator, and because the local electromagnetic state density formed by the metal layer at different temperatures varies little, if the semiconductor material layer is too thin, the metal layer in the substrate is closer to the surface of the radiator, which will make it contribute more to the total local electromagnetic state density, thereby reducing the difference in the local electromagnetic state density above the semiconductor material layer at different temperatures, which is not conducive to achieving a large heat flow regulation performance. If an overly thick semiconductor material layer is used to separate the metal layer from the surface of the radiator, more low-κ modes will be introduced, which is also not conducive to radiation heat flow regulation. Therefore, according to the radiation heat flow regulation device provided by the present invention, when the first radiator contains a first substrate containing a metal layer, the thickness of the semiconductor material layer needs to be moderate (10nm-10mm), and it cannot be too thin or too thick.

Example 3

This embodiment provides a radiation heat flux regulating device without a substrate, which includes a first radiator and a second radiator, wherein the first radiator is made of an intrinsic silicon material, and the second radiator is made of a potassium bromide material; the first radiator is suspended; and the distance between the first radiator and the second radiator is 100 nm. This embodiment analyzes the thermal rectification performance of the radiation heat flux regulating device when the first radiator and the second radiator have different thicknesses.

This embodiment analyzes the thermal rectification performance of the following three typical structures of the radiation heat flux control device, and the relevant parameters include: the high temperature end temperature is 1000K, the low temperature section temperature is 300K, and the analysis results are shown in Table 1 and Figure 15.

Table 1 Performance of thermal diodes based on different structures of intrinsic silicon and potassium bromide combinations

In Table 1, the thickness of the film is 10nm, and the bulk material indicates that the thickness is set to semi-infinite in the calculation (a sufficiently thick layered planar structure is equivalent to a semi-infinite plane in thermal radiation analysis. For example, when the thickness is greater than 100mm, it can be equivalent to semi-infinite for thermal radiation performance analysis).

In Figure 15, (a), (b), and (c) respectively show the structural types of the radiation heat flux control device, (a) indicates the same structural type as "intrinsic silicon bulk material-potassium bromide bulk material" in Table 1, (b) indicates the same structural type as "intrinsic silicon film-potassium bromide bulk material" in Table 1, and (c) indicates the same structural type as "intrinsic silicon film-potassium bromide film" in Table 1; in the figure below (a), (b), and (c), the radiation heat exchange coefficient diagram of the thermal diode of the structure under the forward and reverse temperature bias conditions is shown respectively. Each point in the figure corresponds to an energy transmission channel under a specific frequency and transverse wave vector, and the brighter it is, the stronger the energy transmission capacity of the channel.

As shown in Figure 15, when both the intrinsic silicon and potassium bromide are semi-infinite bulk structures, the thermal diode has more low-κ modes in both the forward and reverse conditions, so there is almost no difference in the forward and reverse heat flows, and the rectification ratio is only 0.03; when the intrinsic silicon bulk is replaced with a suspended 10nm film, the rectification ratio is increased to 1.67×10 ³ , which is mainly due to the significant weakening of the low-κ mode; and when the semi-infinite potassium bromide bulk is also replaced with a suspended 10nm film structure, the rectification ratio can be further increased to 2.52×10 ³ , which is mainly due to the coupling of the surface phonon polaritons on both sides of the potassium bromide film, which causes the peak of its local electromagnetic state density to redshift (i.e. move to a low frequency). At this time, the intrinsic silicon semiconductor in the corresponding frequency band can form a larger difference in local electromagnetic state density as the temperature changes, so the rectification ratio is also further improved.

This embodiment also analyzes the change of the rectification ratio of the thermal diode composed of intrinsic silicon and potassium bromide under the suspended membrane structure with the thickness of the film. The analysis results are shown in Figure 16. As can be seen from Figure 16, the thermal diode composed of the intrinsic silicon film and the potassium bromide film provided by the present invention still has good thermal rectification performance in a larger film thickness range: when the thickness of the intrinsic silicon film is 1-1000nm and the thickness of the potassium bromide film is 1-1000nm, the rectification ratio of the radiation heat flux control device is 1.67×10 ³ -3.07×10 ³ .

Example 4

This embodiment provides a radiation heat flux regulating device without a substrate, comprising a first radiator and a second radiator, wherein the first radiator is made of intrinsic silicon material, and the second radiator is made of doped silicon (doping concentration 10 ¹⁸ cm ^-3 ) material; the first radiator is suspended; and the distance between the first radiator and the second radiator is 100 nm. This embodiment analyzes the thermal rectification performance of the radiation heat flux regulating device when the first radiator and the second radiator have different thicknesses.

This embodiment analyzes the thermal rectification performance of the following three typical structures of the radiation heat flux control device, and the relevant parameters include: the high temperature end temperature is 1000K, the low temperature section temperature is 300K, and the analysis results are shown in Table 2 and Figure 17.

Table 2 Performance of thermal diodes based on intrinsic silicon and doped silicon with different structures

In Table 2, the thickness of the film is 10nm, and the bulk material indicates that the thickness is set to semi-infinite in the calculation (a sufficiently thick layered planar structure is equivalent to a semi-infinite plane in thermal radiation analysis. For example, when the thickness is greater than 100mm, it can be equivalent to semi-infinite for thermal radiation performance analysis).

In Figure 17, (a), (b), and (c) respectively show the structural types of the radiation heat flux control device, (a) indicates the same structural type as "intrinsic silicon bulk material-doped silicon bulk material" in Table 2, (b) indicates the same structural type as "intrinsic silicon film-doped silicon bulk material" in Table 2, and (c) indicates the same structural type as "intrinsic silicon film-doped silicon film" in Table 2; in the figures below (a), (b), and (c), the radiation heat exchange coefficient diagrams of the thermal diode of the structure under the forward and reverse temperature bias conditions are shown respectively. Each point in the figure corresponds to an energy transmission channel under a specific frequency and transverse wave vector, and the brighter it is, the stronger the energy transmission capacity of the channel.

As shown in Figure 17, when both the intrinsic silicon and the doped silicon are semi-infinite bulk structures, the thermal diode has more low-κ modes in both the forward and reverse conditions, so there is almost no difference in the forward and reverse heat flows, and the rectification ratio is only 0.005; when the intrinsic silicon bulk is replaced with a suspended 10nm film, the rectification ratio is increased to 4.66×10 ³ , which is mainly due to the significant weakening of the low-κ mode; and when the semi-infinite doped silicon bulk is also replaced with a suspended 10nm film structure, the rectification ratio can be further increased to 1.27×10 ⁴ , which is mainly due to the coupling of surface plasmon polaritons on both sides of the doped silicon film, which causes the peak of its local electromagnetic state density to redshift (i.e. move to a lower frequency). At this time, the intrinsic silicon semiconductor in the corresponding frequency band can form a larger difference in local electromagnetic state density as the temperature changes, so the rectification ratio is also further improved.

This embodiment also analyzes the change of the rectification ratio of the thermal diode composed of intrinsic silicon and doped silicon under the suspended membrane structure with the thickness of the film. The analysis results are shown in Figure 18. As can be seen from Figure 18, the thermal diode composed of the intrinsic silicon film and the doped silicon film provided by the present invention can still have good thermal rectification performance within a larger film thickness range: when the thickness of the intrinsic silicon film is 1-1000nm and the thickness of the doped silicon film is 1-1000nm, the rectification ratio of the radiation heat flux control device is 2×10 ³ -4.67×10 ³ .

Example 5

This embodiment provides a radiation heat flux control device including a substrate, which includes a first radiator and a second radiator, wherein the first radiator is composed of an intrinsic silicon film and a first substrate, and the second radiator is composed of a potassium bromide film and a second substrate; the first substrate and the second substrate are both composed of silver; the distance between the first radiator and the second radiator is 10nm; the structural schematic diagram of the radiation heat flux control device is shown in Figure 19. This embodiment analyzes the thermal rectification performance of the radiation heat flux control device when the intrinsic silicon film and the potassium bromide film have different thicknesses, and the relevant parameters include: the high temperature end temperature is 1000K, the low temperature section temperature is 300K, and the analysis results are shown in Figure 20.

It can be seen from Figure 20 that for the thermal diode containing a silver substrate, the thickness of the intrinsic silicon and potassium bromide cannot be too thin, otherwise the rectification ratio will be very small due to the excessive participation of the silver substrate in radiation heat exchange; when the thickness of the intrinsic silicon film is 10nm-1mm and the thickness of the potassium bromide film is 1μm-1mm, the rectification ratio of the radiation heat flux control device can reach more than 200.

Example 6

This embodiment provides a radiation heat flux regulating device including a substrate, which includes a first radiator and a second radiator, wherein the first radiator is composed of an intrinsic silicon film and a first substrate, and the second radiator is composed of a doped silicon (doping concentration 10 ¹⁸ cm ^-3 ) film and a second substrate; the first substrate and the second substrate are both composed of silver; the distance between the first radiator and the second radiator is 10 nm; the structural schematic diagram of the radiation heat flux regulating device is shown in FIG21. This embodiment analyzes the thermal rectification performance of the radiation heat flux regulating device when the intrinsic silicon film and the doped silicon film have different thicknesses, and the relevant parameters include: the high temperature end temperature is 1000K, the low temperature section temperature is 300K, and the analysis results are shown in FIG22.

As can be seen from FIG. 22, for the thermal diode containing the silver substrate, the thickness of the intrinsic silicon and the doped silicon cannot be too thin, otherwise the silver substrate will participate too much in the radiation heat exchange, resulting in a very small rectification ratio; when the thickness of the intrinsic silicon film is 10 μm-100 μm, and the thickness of the doped silicon film is 100 μm-1 mm, the rectification ratio of the radiation heat flux control device can reach about 80. The rectification ratio achievable by the thermal diode of this embodiment is smaller than that achievable by the thermal diode of Example 3, mainly because, compared with polar materials, using doped semiconductor materials to separate the metal substrate will bring about a larger κ mode.

Example 7

This embodiment provides a radiation heat flux control device including a non-metallic substrate, which includes a first radiator and a second radiator, wherein the first radiator is composed of an intrinsic silicon film and a first substrate, and the second radiator is composed of a doped silicon (doping concentration 6×10 ¹⁸ cm ^-3 ) film, a potassium bromide film and a second substrate; the first substrate and the second substrate are both composed of silver; the distance between the first radiator and the second radiator is 10nm; the structural schematic diagram of the radiation heat flux control device is shown in FIG23. This embodiment analyzes the thermal rectification performance of the radiation heat flux control device when the thickness of the doped silicon film is 1nm, and the intrinsic silicon film and the doped silicon film have different thicknesses. The relevant parameters include: the high temperature end temperature is 1000K, and the low temperature section temperature is 300K. The analysis results are shown in FIG24.

Compared with the thermal diode provided in Example 4, the thermal diode of this embodiment adds a polar material layer as a spacer between the doped semiconductor material layer and the second substrate. Since the real part of the dielectric constant ε′ of potassium bromide is smaller than that of doped silicon, using potassium bromide to separate the silver substrate will not introduce too many low-κ modes. As can be seen from Figure 24, when the thickness of the intrinsic silicon film is 10nm-1mm and the thickness of the potassium bromide film is 1μm-1mm, the rectification ratio of the radiation heat flux regulation device can reach more than 400; when the thickness of the intrinsic silicon film is 20nm-1mm and the thickness of the potassium bromide film is 1μm-1mm, the rectification ratio of the radiation heat flux regulation device can reach about 700.

Example 8

The present embodiment provides a radiation heat flux regulation device comprising a substrate, which includes a first radiator and a second radiator, the first radiator is composed of an intrinsic silicon film (with a thickness of 10 nm) and a first substrate, and the second radiator is composed of cubic boron nitride; the first substrate is composed of potassium bromide, the thickness of the intrinsic silicon film is 10 nm, and the first radiator is suspended; the second radiator is a block material; the distance between the first radiator and the second radiator is 100 nm; the structural schematic diagram of the radiation heat flux regulation device is shown in Figure 25.

This embodiment analyzes the thermal rectification performance of the radiation heat flux regulating device when the first substrate has different thicknesses, and the relevant parameters include: the high temperature end temperature is 1000K, the low temperature section temperature is 300K, and the analysis results are shown in Table 3. For ease of comparison, Table 3 also lists the performance analysis results when the first substrate does not exist, that is, the thickness of the first substrate is 0.

Table 3 Performance of thermal diodes with different thicknesses of KBr substrates

According to the results shown in Table 3, when the first radiator is suspended, the semiconductor material layer can be covered on the non-metallic substrate, and this type of configuration can also obtain greater thermal rectification performance. However, as the thickness of the non-metallic substrate layer increases, its contribution to near-field thermal radiation increases, and the radiation heat flux contributed by the non-metallic substrate is insensitive to changes in the temperature bias direction of the thermal diode, so the rectification performance gradually decreases.

In addition, it is found through analysis that when the second radiator adopts a second substrate made of non-metallic material, a similar situation also exists. When the second radiator is suspended, the polar material layer or doped semiconductor material layer in the second radiator is covered on the second substrate made of non-metallic material, which can also obtain better thermal rectification performance.

The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims (26)

1. A radiation heat flux regulating device based on semiconductor materials, characterized in that the radiation heat flux regulating device comprises a first radiator and a second radiator, wherein the first radiator and the second radiator are arranged opposite to each other; The second radiator is provided with one or a combination of a polar material layer and a doped semiconductor material layer; The first radiator is provided with a semiconductor material layer, wherein the semiconductor material layer contains one or both of an intrinsic semiconductor material and a doped semiconductor material having a carrier doping concentration less than 10 ¹⁶ cm ^-3 ; the thickness of the semiconductor material layer is greater than 10 nm and less than or equal to 1000 nm; The first radiator is arranged in one of the following ways: (a) the first radiator is composed of the semiconductor material layer, and the first radiator is suspended in the air; (b) the first radiator further includes a first substrate, the first substrate is made of a non-metallic material, the semiconductor material layer covers the first substrate, and the first radiator is suspended; (c) The first radiator further includes a first substrate, the first substrate includes a first metal material layer, and the semiconductor material layer covers the first substrate. 2. The radiation heat flux regulating device according to claim 1 is characterized in that the distance between the first radiator and the second radiator is 1 nm-10 mm. 3. The radiation heat flux regulating device according to claim 1 is characterized in that the distance between the first radiator and the second radiator is 10 nm-100 μm. 4. The radiation heat flux regulating device according to claim 1 is characterized in that the volume proportion of the semiconductor material in the semiconductor material layer is 30%-100%. 5. The radiation heat flux control device according to claim 1 is characterized in that in the semiconductor material layer, the semiconductor material is selected from one or a combination of two or more of silicon, germanium, gallium phosphide, gallium arsenide, indium arsenide, boron, tellurium, selenium, gallium nitride, indium nitride, aluminum nitride, aluminum oxide, silicon carbide, zinc oxide, silicon nitride, gallium antimonide, zinc sulfide, cadmium telluride, mercury telluride, cuprous bromide, cuprous iodide, bismuth telluride, bismuth selenide, bismuth sulfide, and arsenic telluride. 6. The radiation heat flux regulating device according to claim 1 is characterized in that the volume proportion of the metal material in the first metal material layer is greater than 20%. 7. The radiation heat flux regulating device according to claim 1 is characterized in that in the first metal material layer, the metal material is selected from one or a combination of two or more of silver, gold and aluminum. 8. The radiation heat flux regulating device according to claim 1 is characterized in that the distance between the midpoint of the vertical line between the first radiator and the second radiator and the first metal material layer is 10 nm-100 mm. 9. The radiation heat flux regulating device as described in claim 1 is characterized in that the thickness of the first substrate is 1 nm-100 mm. 10. The radiation heat flux regulating device according to claim 1 is characterized in that the thickness of the first metal material layer is 1 nm-100 mm. 11. The radiation heat flux regulating device according to claim 1, characterized in that in the polar material layer, the volume proportion of the polar material is 30%-100%. 12. The radiation heat flux control device according to claim 1 is characterized in that in the polar material layer, the polar material is selected from one or a combination of two or more of sodium chloride, potassium bromide, potassium chloride, barium fluoride, cesium fluoride, calcium fluoride, lithium fluoride, gallium nitride, magnesium oxide, cesium bromide, cesium iodide, zinc sulfide, silver bromide, silver chloride, cubic boron nitride, silicon carbide, silicon dioxide, hexagonal boron nitride, zinc selenide, sapphire, cadmium telluride, and silicon dioxide. 13. The radiation heat flux regulating device according to claim 1, characterized in that the thickness of the polar material layer is 1nm-100mm. 14. The radiation heat flux regulating device according to claim 1 is characterized in that the thickness of the polar material layer is 1 nm-10 mm. 15. The radiation heat flux regulating device according to claim 1, characterized in that in the second radiator, the doped semiconductor material layer is composed of a doped semiconductor material with a carrier doping concentration greater than 10 ¹⁵ cm ^-3 . 16. The radiation heat flux control device according to claim 1 is characterized in that in the second radiator, in the doped semiconductor material layer, the doped semiconductor material is selected from one or a combination of two or more of silicon, germanium, gallium phosphide, gallium arsenide, indium arsenide, boron, tellurium, selenium, gallium nitride, indium nitride, aluminum nitride, aluminum oxide, silicon carbide, zinc oxide, silicon nitride, gallium antimonide, zinc sulfide, cadmium telluride, mercury telluride, cuprous bromide, cuprous iodide, bismuth telluride, bismuth selenide, bismuth sulfide, and arsenic telluride. 17. The radiation heat flux regulating device according to claim 1 is characterized in that in the second radiator, the thickness of the doped semiconductor material layer is 1 nm-100 mm. 18. The radiation heat flux regulating device according to claim 1 is characterized in that in the second radiator, the thickness of the doped semiconductor material layer is 1 nm-10 mm. 19. The radiation heat flux regulating device according to claim 1, characterized in that the second radiator further comprises a second substrate, and the polar material layer, the doped semiconductor material layer or a combination of the two is covered on the second substrate; The second substrate includes a second metal material layer, and the metal material accounts for more than 20% (V/V) in the second metal material layer. 20. The radiation heat flux regulating device according to claim 19, characterized in that in the second metal material layer, the metal material is selected from one or a combination of two or more of silver, gold and aluminum. 21. The radiation heat flux regulating device according to claim 19, characterized in that the distance between the midpoint of the vertical line between the first radiator and the second radiator and the second metal material layer is 10 nm-100 mm. 22. The radiation heat flux regulating device according to claim 19, characterized in that the thickness of the second metal material layer is 1 nm-100 mm. 23. The radiation heat flux regulating device according to claim 1, characterized in that one or more radiators are further arranged between the first radiator and the second radiator. 24. Use of the radiation heat flux regulating device according to any one of claims 1 to 23 in heat flux regulation. 25. A heat flux regulator, characterized in that the heat flux regulator comprises the radiation heat flux regulating device according to any one of claims 1-23. 26. The heat flow regulator according to claim 25, characterized in that the heat flow regulator is a thermal diode, a thermal triode or a thermal switch.