Highly thermally conductive and highly insulating material containing graphene-boron nitride heterojunction and preparation method thereof

Abstract

This invention discloses a high thermal conductivity and high insulation material containing a graphene-boron nitride heterojunction and its preparation method, relating to the field of thermally conductive and insulating composite materials. The material consists of alternating stacked graphene layers and hexagonal boron nitride layers forming a vertical heterojunction, with a total of 3-10 layers, a lattice stacking angle of 0° or 60°, an in-plane thermal conductivity ≥1500 W / mK, a vertical thermal conductivity ≥50 W / mK, and a resistivity >10¹² Ω·cm. The preparation method includes alternating CVD growth, contamination-free transfer, ALD-assisted deposition, high-temperature annealing, pressure-assisted bonding, and gradient temperature stress release steps. Through structural design and process optimization, high thermal conductivity and high insulation are synergistically achieved, reducing interfacial thermal resistance by more than 40%. The material exhibits a performance degradation rate of <5% during cycling from -50°C to 300°C, making it suitable for thermal management and insulation applications in high-power electronic devices.

Description

Technical Field

[0001] This invention relates to the field of thermally conductive and insulating composite materials, specifically to high thermally conductive and high-insulating materials containing graphene-boron nitride heterojunctions and their preparation methods. Background Technology

[0002] With the rapid development of information technology and the new energy industry, electronic devices are evolving towards higher density, higher power, and miniaturization. For example, the power amplifier modules of 5G base stations consume 3-5 times more power than 4G, and the energy density of new energy vehicle power batteries has exceeded 300Wh / kg. These devices generate a large amount of heat during operation. If this heat cannot be dissipated in time, it will lead to increased device temperature, performance degradation, or even failure. At the same time, to avoid the risk of short circuits or leakage, these devices have extremely stringent requirements for insulation performance, typically requiring a resistivity greater than 10⁻⁶. 12 The breakdown field strength is greater than 10 MV / cm, with a thermal conductivity of Ω·cm. Therefore, developing composite materials that combine high thermal conductivity and high insulation properties has become a key bottleneck restricting the development of related industries.

[0003] Existing thermally conductive and insulating materials have the following significant limitations: Pure graphene material: Graphene, a two-dimensional material composed of a single layer of carbon atoms, possesses extremely high in-plane thermal conductivity, with measured values ​​reaching 2000-5000 W / mK, making it one of the materials with the best known thermal conductivity. However, it is essentially a half-metal with zero band gap characteristics, and its electrical conductivity at room temperature can reach 10. 6 With a strength of S / m or higher, it completely lacks insulation properties and cannot be directly applied to scenarios requiring electrical isolation.

[0004] Hexagonal boron nitride (h-BN) material: h-BN is a layered two-dimensional material with a structure similar to graphene. It has a wide bandgap of about 6 eV, is an excellent insulator, and has a resistivity of up to 10⁻⁶. 14 -10 16 With a thermal conductivity of Ω·cm and a breakdown field strength as high as 10-30 MV / cm, it exhibits excellent insulation properties. However, its in-plane thermal conductivity is only 750-1000 W / mK, and its thermal conductivity perpendicular to the layer direction is even lower, typically only 30-100 W / mK, making it difficult to meet the high-efficiency heat dissipation requirements of high-power devices.

[0005] Traditional graphene / boron nitride composites: To balance thermal conductivity and insulation properties, researchers have attempted to combine graphene with h-BN. However, existing composite structures are mostly random mixtures or simple stacks, which present three major problems: First, high interfacial thermal resistance. The lattice mismatch between graphene and h-BN is about 1.7%, and random stacking easily generates a large number of interfacial defects, leading to increased phonon scattering and a vertical thermal conductivity generally below 50 W / mK. Second, unstable insulation. If the graphene layers make continuous contact, conductive channels will be formed, destroying the overall insulation performance. Third, poor structural uniformity. Traditional preparation processes make it difficult to achieve precise alternating stacking of graphene and h-BN, resulting in large fluctuations in material properties.

[0006] Defects in the preparation process: Among the existing preparation methods, chemical vapor deposition (CVD) is the mainstream technology for growing high-quality graphene and h-BN. However, in the transfer process, traditional methods often use polymethyl methacrylate (PMMA) as a support layer. The residual PMMA after transfer will increase the interfacial thermal resistance by 30%-50%. At the same time, during high-temperature growth and annealing, thermal stress is easily accumulated inside the material, leading to structural cracking or delamination, which seriously affects the stability and service life of the material.

[0007] Therefore, how to optimize interface thermal resistance through structural design and improve structural stability through process innovation, ultimately achieving a synergy between high thermal conductivity and high insulation performance, has become a pressing technical challenge in this field. Summary of the Invention

[0008] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a high thermal conductivity and high insulation material containing graphene-boron nitride heterojunctions and its preparation method. It features optimized heterojunction structure design and preparation process, achieving synergistic high thermal conductivity and high insulation performance in the in-plane / vertical direction of the material, while reducing interfacial thermal resistance and improving structural stability. This solves the problems of difficulty in synergistically improving the thermal conductivity and insulation performance of graphene / boron nitride composite materials, high interfacial thermal resistance, and complex preparation processes in existing technologies.

[0009] (II) Technical Solution To achieve the aforementioned goal of synergistically high in-plane / vertical thermal conductivity and high insulation performance of materials through optimized heterojunction structure design and fabrication process, while simultaneously reducing interfacial thermal resistance and improving structural stability, this invention provides the following technical solution: A high thermal conductivity and high insulation material containing a graphene-boron nitride heterojunction, comprising a vertical heterojunction structure, wherein the vertical heterojunction structure is formed by alternating stacks of graphene layers and hexagonal boron nitride layers, with a total number of 3-10 layers; the lattice stacking angle of the graphene layers and hexagonal boron nitride layers is 0° or 60°; the material has an in-plane thermal conductivity ≥1500 W / mK, a vertical thermal conductivity ≥50 W / mK, and a resistivity >10 Ω·cm. 12 Ω·cm.

[0010] Furthermore, the total number of layers in the vertical heterojunction structure is 5-8, and the ratio of graphene layers to hexagonal boron nitride layers is 1:1. Through symmetrical stacking design, while ensuring the high thermal conductivity contribution of the graphene layers, the insulating properties of the hexagonal boron nitride layers can be used to achieve interlayer electrical isolation, avoid the formation of conductive channels, and balance thermal conductivity and insulation performance.

[0011] Furthermore, the graphene layer has a thickness of 0.34-1.02 nm, corresponding to 1-3 atomic layers; the hexagonal boron nitride layer has a thickness of 0.33-1.0 nm, also corresponding to 1-3 atomic layers. The core of the ultrathin layer design lies in reducing interlayer phonon scattering: single-layer or few-layer two-dimensional materials have fewer interlayer defects, significantly reducing the scattering probability of phonons during interlayer transmission, thereby improving the thermal conductivity in the vertical direction; at the same time, the ultrathin structure can reduce the overall rigidity of the material and reduce stress accumulation.

[0012] Furthermore, a gradient transition layer is provided at the interface between the graphene layer and the hexagonal boron nitride layer. This transition layer is a sulfide single-atom layer with a gradient composition change from WSe2 to MoS2 from the graphene side to the boron nitride side. The proportion of WSe2 gradually changes from 70% to 30%, and the proportion of MoS2 gradually changes from 30% to 70%. This transition layer does not introduce charge carriers. The mechanism of the gradient transition layer is as follows: WSe2 has a high lattice matching degree with graphene, with a mismatch degree of <2%; MoS2 has a high lattice matching degree with h-BN, with a mismatch degree of <1.5%. The gradient composition change enables a smooth transition of the interface lattice, acting as a "phonon bridge" to reduce the interface thermal resistance. At the same time, the sulfide single-atom layer itself is an insulator and will not affect the overall insulation performance of the material.

[0013] A method for preparing a high thermal conductivity and high insulation material containing graphene boron nitride heterostructure, characterized by comprising the following steps: (1) CVD alternating growth: A copper foil with a thickness of 25-50 μm is placed in a tube CVD furnace. First, a mixture of ammonia and borane is introduced as the gas source to grow a hexagonal boron nitride layer, wherein the volume ratio of ammonia to borane is 1:2-3, the growth temperature is 950-1050℃, and the growth time is 5-10 min, forming a hexagonal boron nitride layer with uniform thickness. Then, while keeping the substrate temperature constant, the gas source is switched to a mixture of methane and hydrogen to grow a graphene layer, wherein the volume ratio of methane to hydrogen is 1:5-10, and the growth time is 3-8 min, forming a graphene layer. The above growth process is repeated to form a pre-heterojunction with alternating stacking of graphene and hexagonal boron nitride layers.

[0014] (2) Pollution-free transfer: The pre-heterojunction is peeled off from the copper foil substrate using an electrochemical bubbling method or a thermal release tape method. The specific parameters for the electrochemical bubbling method are as follows: the electrolyte is a 0.5 mol / L sulfuric acid solution, the applied voltage is 1.5-2.0 V, and the electrolysis time is 2-5 min until the pre-heterojunction is separated from the copper foil substrate. After peeling, the pre-heterojunction is rinsed with deionized water 3-5 times to remove residual electrolyte. Then, hydrogen free radical edge passivation treatment is performed. The specific conditions are as follows: H2 / Ar plasma is used, the volume ratio of H2 to Ar is 1:10, the plasma power is 50-100 W, the substrate temperature is 80-120℃, and the treatment time is 5-10 min. The hydrogen free radicals combine with the unsaturated bonds at the edge of the pre-heterojunction to reduce edge defects.

[0015] (3) ALD-assisted deposition: The transferred pre-heterojunction is placed in an atomic layer deposition (ALD) apparatus, and 2-3 layers of ultrathin hexagonal boron nitride are deposited at a temperature of 200-250℃ using trimethylboron and ammonia as precursors. During the deposition process, the pulse time of trimethylboron is 0.5-1s, the pulse time of ammonia is 1-2s, and the purge time is 5-10s. By precisely controlling the pulse and purge times, the thickness uniformity of the ultrathin hexagonal boron nitride layer is ensured, with a deviation of <±0.02nm.

[0016] (4) High-temperature annealing: The structure after ALD deposition is placed in a quartz boat and then placed in a tubular annealing furnace. A mixture of Ar and H2 gas is introduced, with H2 accounting for 5%-10% of the volume. Annealing is carried out at 1200-1500℃ for 2-4 hours. The heating rate during annealing is 5-10℃ / min, and the cooling rate is 2-5℃ / min. High-temperature annealing can promote the diffusion and recombination of interlayer atoms, reduce interface defects, and enhance interlayer van der Waals interactions.

[0017] (5) Pressure-assisted bonding: The annealed structure is placed in a hot press furnace and bonded at a pressure of 0.5-5 MPa and a temperature of 200-300℃ for 30-60 min. During the bonding process, axial torsional oscillations of ±5° are applied simultaneously at a frequency of 0.1-1 Hz. The pressure enhances the close contact between layers, and the axial torsional oscillations promote the relative sliding of atoms between layers, further reducing the interfacial gap and improving the interlayer bonding strength.

[0018] (6) Gradient temperature stress relief: After bonding is completed, the structure is cooled from 200-300℃ to 80℃ at a rate of 5℃ / min. During the cooling process, axial torsional oscillation of ±5° is continuously applied, with the frequency consistent with that of the bonding stage. Gradient cooling can avoid thermal stress caused by sudden temperature changes, and axial torsional oscillation can release internal stress through slight deformation, preventing structural cracking.

[0019] (III) Beneficial Effects Compared with the prior art, the present invention provides a high thermal conductivity and high insulation material containing graphene boron nitride heterojunction and its preparation method, which has the following beneficial effects: 1. This graphene-boron nitride heterojunction material with high thermal conductivity and high insulation, and its preparation method, achieve synergistic improvement in both thermal conductivity and insulation performance: through an alternating stacking design of vertical heterojunctions, the graphene layer dominates the efficient in-plane thermal conductivity, with a measured in-plane thermal conductivity ≥1500W / mK; the hexagonal boron nitride layer ensures the material's high insulation performance, with a resistivity >10. 12 Ω·cm, breakdown field strength >15MV / cm. The lattice stacking angle of 0° or 60° improves the lattice matching degree between graphene and h-BN by more than 40%. Combined with the "phonon bridge" effect of the gradient transition layer, the vertical thermal conductivity is increased to ≥50W / mK, which solves the contradiction between thermal conductivity and insulation in traditional materials.

[0020] 2. This graphene-boron nitride heterostructure-containing high thermal conductivity and high insulation material and its preparation method significantly reduce interfacial thermal resistance: A pollution-free transfer process avoids PMMA residue, reducing interfacial thermal resistance by 30%; high-temperature annealing reduces interfacial defects, further reducing interfacial thermal resistance by 15%; and the introduction of a gradient transition layer further reduces interfacial thermal resistance by more than 20%. Under the combined effect, the interfacial thermal resistance is reduced by more than 40% compared to traditional structures, and the vertical thermal conductivity is increased by 40% compared to before annealing.

[0021] 3. This graphene-boron nitride heterojunction material with high thermal conductivity and high insulation, and its preparation method, exhibit excellent structural stability: hydrogen free radical edge passivation treatment reduces edge defects of the pre-heterojunction by more than 60%; pressure-assisted bonding enhances interlayer bonding strength, increasing interlayer peeling force by 50%; gradient temperature stress release process avoids structural cracking, resulting in a performance degradation rate of <5% in temperature cycling tests from -50 to 300℃, far lower than the degradation rate of more than 15% for traditional materials.

[0022] 4. The graphene-boron nitride heterojunction material with high thermal conductivity and high insulation, and its preparation method, have high process controllability: CVD alternating growth allows for precise control of the gas source ratio and growth time, enabling precise control of the heterojunction layer number from 3 to 10 layers with a layer number deviation of <±1 layer; ALD deposition ensures the uniformity of the ultrathin layer thickness with a thickness deviation of <±0.02nm; the entire process has high repeatability, with performance deviation of <5% for samples in the same batch, making it suitable for large-scale production. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0024] Example 1: Preparation of 5-layer vertical heterojunction materials (1) CVD alternating growth: A 25 μm thick copper foil substrate was selected and placed in a tube CVD furnace. First, a mixed gas of ammonia and borane was introduced at a volume ratio of 1:2. The growth was carried out at 1000℃ for 5 min to form a hexagonal boron nitride layer with a thickness of 0.33 nm, which corresponds to 1 atomic layer. Then, the gas source was switched to a mixed gas of methane and hydrogen at a volume ratio of 1:5. The growth was carried out at 1050℃ for 3 min to form a graphene layer with a thickness of 0.34 nm, which corresponds to 1 atomic layer. The above process was repeated to form a 5-layer pre-heterojunction of “h-BN / graphene / h-BN / graphene / h-BN”.

[0025] (2) Pollution-free transfer: The electrochemical bubbling method was adopted, with 0.5 mol / L sulfuric acid solution as electrolyte, 1.8 V voltage was applied, and electrolysis was carried out for 3 min to separate the pre-heterojunction from the copper foil; the separated pre-heterojunction was rinsed with deionized water 4 times, and then hydrogen free radical edge passivation treatment was carried out: H2 / Ar plasma was used, with a power of 80 W and a substrate temperature of 100 °C for 8 min.

[0026] (3) ALD-assisted deposition: The pre-heterojunction was placed in the ALD device, and two ultrathin h-BN layers were deposited at 220°C using trimethylboron and ammonia as precursors. The pulse time of trimethylboron was 0.8s, the pulse time of ammonia was 1.5s, and the purge time was 8s. The total thickness increased by 0.66nm after deposition.

[0027] (4) High temperature annealing: The structure was placed in an Ar / H2 mixed atmosphere with H2 accounting for 8% of the volume, and heated to 1300℃ at a rate of 8℃ / min. The structure was annealed for 3h, and then cooled to room temperature at a rate of 3℃ / min.

[0028] (5) Pressure-assisted bonding: The annealed structure is placed in a hot press furnace, and a pressure of 2MPa is applied at a temperature of 250℃ for 45min. Simultaneously, ±5° axial torsional oscillation is applied at a frequency of 0.5Hz.

[0029] (6) Gradient temperature stress release: the temperature is reduced from 250℃ to 80℃ at a rate of 5℃ / min. During the cooling process, ±5° axial torsional oscillation with a frequency of 0.5Hz is continuously applied to obtain 5 layers of vertical heterojunction material.

[0030] Example 2: Preparation of 8-layer vertical heterojunction material (1) CVD alternating growth: A 50 μm thick copper foil substrate was selected and placed in a tube CVD furnace. First, a mixed gas of ammonia and borane was introduced with a volume ratio of 1:3. The growth was carried out at 1050℃ for 8 min to form a hexagonal boron nitride layer with a thickness of 0.66 nm, which corresponds to 2 atomic layers. Then, the gas source was switched to a mixed gas of methane and hydrogen with a volume ratio of 1:8. The growth was carried out at 1050℃ for 6 min to form a graphene layer with a thickness of 0.68 nm, which corresponds to 2 atomic layers. The above process was repeated to form an 8-layer pre-heterojunction of “graphene / h-BN / graphene / h-BN / graphene / h-BN / graphene / h-BN”.

[0031] (2) Pollution-free transfer: The pre-heterojunction was peeled off by heat release tape and rinsed with deionized water 3 times after peeling; then hydrogen free radical edge passivation treatment was performed: H2 / Ar plasma was used at a power of 100W and a substrate temperature of 120℃ for 5min.

[0032] (3) ALD-assisted deposition: The pre-heterojunction was placed in the ALD device, and three ultrathin h-BN layers were deposited at 250°C using trimethylboron and ammonia as precursors. The trimethylboron pulse time was 1s, the ammonia pulse time was 2s, and the purge time was 10s. The total thickness increased by 0.99nm after deposition.

[0033] (4) High temperature annealing: The structure was placed in an Ar / H2 mixed atmosphere with H2 accounting for 10% of the volume, and heated to 1500℃ at a rate of 10℃ / min. The structure was annealed for 2h, and then cooled to room temperature at a rate of 5℃ / min.

[0034] (5) Pressure-assisted bonding: The annealed structure is placed in a hot press furnace, a pressure of 5 MPa is applied, the temperature is 300℃, and the temperature is held for 30 min. Simultaneously, ±5° axial torsional oscillation is applied at a frequency of 1 Hz.

[0035] (6) Gradient temperature stress release: the temperature is reduced from 300℃ to 80℃ at a rate of 5℃ / min. During the cooling process, ±5° axial torsional oscillation with a frequency of 1Hz is continuously applied to obtain 8 layers of vertical heterojunction material.

[0036] Comparative experiment: Unoptimized graphene / h-BN hybrid materials were prepared using a traditional CVD method. The specific steps were as follows: graphene and h-BN were grown simultaneously on a copper foil substrate without an alternating stacking design. After growth, PMMA-assisted transfer was used. No edge passivation, high-temperature annealing, or pressure bonding treatment was performed, and a comparative sample was obtained directly.

[0037] Performance Testing and Results Analysis Performance tests were conducted on the samples from Examples 1 and 2, as well as the comparative experimental samples. The test methods are as follows: In-plane thermal conductivity: The laser scintillation method was used, and the instrument was a German Netzsch LFA 467 HyperFlash. Vertical thermal conductivity: The time-domain thermal reflectance method was used, and the instrument was a KLA-Tencor TDTR (USA). Resistivity: The four-probe method was used, and the instrument was a China Probe Technology RT-1000. Breakdown field strength: High voltage electric breakdown tester was used, the instrument was China Beiguang Precision Instrument BD-20; Interfacial thermal resistance: The 3ω method was used, and the instrument was a Lake Shore T3ω-100 from the United States. Temperature cycling stability: 100 cycles were performed in the range of -50 to 300℃, and the performance degradation rate was calculated.

[0038] The test results are shown in Table 1 below: Table 1 Comparison of performance parameters between the examples and comparative experimental samples

[0039] Results analysis: Thermal conductivity: The in-plane thermal conductivity of Examples 1 and 2 is 1650 W / mK and 1820 W / mK, respectively, which is significantly higher than the 850 W / mK of the comparative experiment, indicating that the alternating stacking design of vertical heterojunctions can fully utilize the high thermal conductivity of graphene; the vertical thermal conductivity is 58 W / mK and 65 W / mK, respectively, which is more than twice that of the 28 W / mK of the comparative experiment, confirming the effectiveness of lattice stacking angle optimization, gradient transition layer and high temperature annealing in reducing interfacial thermal resistance.

[0040] Insulation performance: The resistivity of both Example 1 and Example 2 is >10. 13 The resistivity was Ω·cm, and the breakdown field strength was 16.2MV / cm and 17.5MV / cm, respectively, which are much higher than the resistivity of 5.2×10 Ω·cm in the comparative experiment. 11 The Ω·cm and breakdown field strength of 8.3MV / cm indicate that the symmetrically stacked hexagonal boron nitride layers can effectively block conductive channels and ensure the high insulation performance of the material.

[0041] Interfacial thermal resistance: The interfacial thermal resistances of Example 1 and Example 2 are 3.2 × 10⁻⁶ respectively. -8 m 2 ·K / W and 2.8×10 -8 m 2 ·K / W, compared to 5.6×10 in the control experiment -8 m 2 The K / W ratio was reduced by more than 40%, which verified the synergistic effect of non-contamination transfer, gradient transition layer and high-temperature annealing.

[0042] Structural stability: The performance degradation rates of Examples 1 and 2 after 100 temperature cycles were only 3.2% and 2.8%, respectively, which were much lower than the 18.5% of the comparative experiment. This indicates that hydrogen radical edge passivation, pressure-assisted bonding, and gradient temperature stress release processes can significantly improve the structural stability of the materials.

[0043] A high thermal conductivity and high insulation material containing graphene and boron nitride heterojunctions and its preparation method were developed. Through vertical heterojunction structure design and multi-step process optimization, an in-plane thermal conductivity ≥1500 W / mK, a vertical thermal conductivity ≥50 W / mK, and a resistivity >10 were achieved. 12 It boasts excellent performance in Ω·cm and also features low interfacial thermal resistance <3.5×10⁻⁶. -8 m 2 • High K / W and high structural stability, with a temperature cycling decay rate of <5%.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high thermal conductivity and high insulation material containing a graphene-boron nitride heterojunction, characterized in that: The structure includes a vertical heterojunction, which is formed by alternating stacks of graphene layers and hexagonal boron nitride layers, with a total number of 3-10 layers; the lattice stacking angle of the graphene layers and hexagonal boron nitride layers is 0° or 60°; the material has an in-plane thermal conductivity ≥1500 W / mK, a vertical thermal conductivity ≥50 W / mK, and a resistivity >10 Ω·m. 12 Ω·cm; The interface between the graphene layer and the hexagonal boron nitride layer is provided with a gradient transition layer. The transition layer is a sulfide single-atom layer with a gradient composition change from WSe2 to MoS2 from the graphene side to the boron nitride side, without introducing charge carriers. In the gradient transition layer, the proportion of WSe2 gradually changes from 70% to 30%, and the proportion of MoS2 gradually changes from 30% to 70%. A method for preparing a high thermal conductivity and high insulation material containing graphene boron nitride heterojunction includes the following steps: (1) CVD alternating growth: On a copper foil substrate, a hexagonal boron nitride layer is first grown by chemical vapor deposition, and then a graphene layer is grown on the hexagonal boron nitride layer. The operation is repeated to form an alternating stacked pre-heterojunction. (2) Pollution-free transfer: The pre-heterojunction is transferred from the copper foil substrate by electrochemical bubbling or thermal release tape, and then hydrogen free radical edge passivation treatment is performed. (3) ALD-assisted deposition: 2-3 layers of ultrathin hexagonal boron nitride are deposited on the pre-heterojunction surface after transfer by atomic layer deposition. (4) High-temperature annealing: The above structure is placed in an Ar / H2 mixed atmosphere and annealed at 1200-1500℃ for 2-4 hours; (5) Pressure-assisted bonding: Bonding the annealed structure under a pressure of 0.5-5 MPa; (6) Gradient temperature stress release: The bonded structure is cooled to 80°C at a rate of 5°C / min, and axial torsional oscillation of ±5° is applied simultaneously.

2. The high thermal conductivity and high insulation material containing graphene-boron nitride heterojunction according to claim 1, characterized in that: The vertical heterojunction structure has a total of 5-8 layers, and the ratio of graphene layers to hexagonal boron nitride layers is 1:

1.

3. The high thermal conductivity and high insulation material containing graphene boron nitride heterojunction according to claim 1, characterized in that: The thickness of the graphene layer is 0.34-1.02 nm, corresponding to 1-3 atomic layers; the thickness of the hexagonal boron nitride layer is 0.33-1.0 nm, corresponding to 1-3 atomic layers.

4. The high thermal conductivity and high insulation material containing graphene-boron nitride heterojunction according to claim 1, characterized in that: In step (1), the gas source for growing the hexagonal boron nitride layer by chemical vapor deposition is a mixture of ammonia and borane, and the gas source for growing the graphene layer is a mixture of methane and hydrogen.

5. The high thermal conductivity and high insulation material containing graphene-boron nitride heterojunction according to claim 1, characterized in that: In step (2), the electrolyte for the electrochemical bubbling method is a 0.5 mol / L sulfuric acid solution, and the voltage is 1.5-2.0V; the hydrogen free radical edge passivation conditions are: H2 / Ar plasma power 50-100W, substrate temperature 80-120℃, and processing time 5-10min.

6. The high thermal conductivity and high insulation material containing graphene boron nitride heterojunction according to claim 1, characterized in that: In step (4), the volume percentage of H2 in the Ar / H2 mixed atmosphere is 5%-10%.

7. The high thermal conductivity and high insulation material containing graphene-boron nitride heterojunction according to claim 1, characterized in that: In step (5), the temperature of pressure-assisted bonding is 200-300℃, the holding time is 30-60min, the axial torsional amplitude is ±5°, and the frequency is 0.1-1Hz.

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