Method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface

Abstract

The invention discloses a method for measuring thermal conductivity of a suspended graphene / two-dimensional material heterojunction interface. Comprising the following four steps: calibrating environment temperature coefficients of graphene and a two-dimensional material in the suspended graphene / two-dimensional material heterojunction device, measuring Raman spectrum peak position offset of the graphene and the two-dimensional material under a set voltage, and measuring lattice temperature difference of the graphene and the two-dimensional material and heat conductivity of a heterojunction interface. The method fills the blank of the method for measuring the thermal conductivity of the suspended graphene / two-dimensional material heterojunction interface, can be expanded to be suitable for all suspended heterojunction systems, and meets the requirements for measuring the thermal conductivity of different types of suspended two-dimensional material interfaces. The method has very important value for application of the suspended graphene heterojunction in key fields of high-frequency electronic devices, infrared photoelectric detection, micro-nano electromechanical systems and the like.

Description

Technical Field

[0001] The present invention mainly relates to the field of micro-nano semiconductor testing technology, in particular to a method for measuring thermal conductivity of a suspended graphene / two-dimensional material heterojunction interface. Background Art

[0002] At present, with the rapid development of smart devices, chips are moving towards greater integration and miniaturization. The number of transistors that can be integrated on a single chip has reached billions. The heat dissipation of electronic devices has become an important factor restricting their development, and thermal management challenges have become a difficult problem.

[0003] Suspended graphene can effectively eliminate the effects of wrinkles, carrier scattering and random doping caused by rough substrates. It has excellent intrinsic physical properties such as zero-mass Dirac fermions, high carrier mobility, high thermal conductivity, excellent mechanical and thermal stability, etc., which makes it have very important application prospects in key fields such as high-frequency electronic devices and infrared photoelectric detection. The heterojunction system composed of graphene and two-dimensional materials can effectively regulate the electrical properties of graphene. For example, the heterojunction structure formed by hexagonal boron nitride covering graphene can effectively protect graphene and prevent graphene from being oxidized by high temperature, so that the device can withstand higher current density.

[0004] As transistors become smaller and smaller, the number of internal interfaces increases. Currently, there is no reported method for measuring the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunctions. There is an urgent need for a method to accurately measure the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunctions. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the present invention proposes a method for measuring the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunction, which can realize the accurate measurement of the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunction, and is used to fill the gap in the method of measuring the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunction.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for measuring thermal conductivity of a suspended graphene / two-dimensional material heterojunction interface comprises the following steps: S1 determines the suspended graphene / two-dimensional material heterojunction device to be measured, performs Raman spectroscopy tests on the heterojunction region of the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures, measures the Raman spectra of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures, and calibrates the ambient temperature coefficients of graphene and two-dimensional materials through the relationship between the Raman spectral peak positions of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device and the ambient temperature; S2 measures the relationship between the Raman spectrum peak shift and the applied voltage in the suspended graphene / two-dimensional material heterojunction device under vacuum, including the graphene Raman spectrum peak and the two-dimensional material Raman spectrum peak shift as the applied voltage changes; S3 calculates the lattice temperature difference of graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device under the set voltage according to the calibrated ambient temperature coefficients of graphene and the two-dimensional material, and the offset of the graphene Raman spectrum peak position and the two-dimensional material Raman spectrum peak position under the set voltage; S4 calculates the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction device at a set voltage based on the lattice temperature difference of graphene and two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at a set voltage, the contact area of ​​the heterojunction interface of the suspended graphene / two-dimensional material heterojunction device, and the injected electric power value of the suspended graphene / two-dimensional material heterojunction device at a set voltage.

[0007] Compared with the prior art, the present invention has the following beneficial effects: The method for measuring the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunction provided by the present invention fills the gap in the method for measuring the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunction, and solves the problem of creating a method for measuring the thermal conductivity of the interface of suspended graphene / two-dimensional material heterojunction from scratch.

[0008] The method for measuring the thermal conductivity of a suspended graphene / two-dimensional material heterojunction interface provided by the present invention comprises four steps: calibrating the ambient temperature coefficient of graphene and two-dimensional materials in a suspended graphene / two-dimensional material heterojunction device, measuring the peak position shift of the Raman spectra of the graphene and two-dimensional materials under a set voltage, and measuring the lattice temperature difference between the graphene and two-dimensional materials and the thermal conductivity of the heterojunction interface. The test steps are simple, the operability is strong, and the method can be expanded to be applicable to all suspended heterojunction systems, meeting the needs of measuring the thermal conductivity of interfaces of different types of suspended two-dimensional materials, and filling the gap in the method for measuring the thermal conductivity of interfaces of suspended graphene / two-dimensional materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0010] Figure 1 Schematic diagram of the structure of a suspended graphene / hexagonal boron nitride heterojunction device in one embodiment; Figure 2Schematic diagram of a suspended heterojunction region between a source electrode and a drain electrode of a suspended graphene / hexagonal boron nitride heterojunction device in one embodiment. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] Suspended graphene / two-dimensional material heterojunction devices have good application prospects in high-frequency electronic devices, infrared photoelectric detection, etc., and the electrical properties of graphene can be effectively regulated through the heterostructure composed of two-dimensional materials and graphene.

[0013] Reference Figure 1 and Figure 2 , Figure 1 is a schematic structural diagram of a suspended graphene / hexagonal boron nitride heterojunction device in one embodiment, Figure 2 Schematic diagram of a suspended heterojunction region between a source electrode and a drain electrode of a suspended graphene / hexagonal boron nitride heterojunction device in an embodiment, wherein the suspended graphene / two-dimensional material heterojunction device comprises a silicon substrate 5, a silicon dioxide layer 4, an electrode layer 3, and a graphene / two-dimensional material heterojunction, wherein the silicon substrate 5 is provided with a silicon dioxide layer 4, and the silicon dioxide layer 4 is provided with an electrode layer 3, wherein the electrode layer 3 comprises a source electrode and a drain electrode, which are respectively arranged on the left and right sides above the silicon dioxide layer 4, and the graphene layer 2 and the two-dimensional material layer 1 in the graphene / two-dimensional material heterojunction are sequentially arranged above the electrode layer 3, and the graphene / two-dimensional material heterojunction region between the source electrode and the drain electrode is the suspended region of the graphene / two-dimensional material heterojunction, and the contact area of ​​the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / two-dimensional material heterojunction device is Figure 2 The area corresponding to the medium gray box selection area, Figure 2 The medium grey boxed area corresponds to the suspended region of the graphene / 2D material heterojunction.

[0014] The thickness of the electrode layer 3 is the height of the graphene / two-dimensional material heterojunction suspended in the air. Figure 2 The area corresponding to the gray box is the contact area of ​​the heterojunction interface of the suspended graphene / two-dimensional material heterojunction device, which corresponds to the contact area of ​​the suspended heterojunction interface between the source electrode and the drain electrode of the suspended graphene / hexagonal boron nitride heterojunction device. SThe two-dimensional material includes all two-dimensional materials that can be combined with graphene to form a graphene / two-dimensional material heterojunction, including hexagonal boron nitride, molybdenum disulfide, tungsten disulfide, molybdenum selenide, tungsten diselenide, etc. In this embodiment, the two-dimensional material is hexagonal boron nitride.

[0015] In one embodiment, a method for measuring thermal conductivity of a suspended graphene / two-dimensional material heterojunction interface is provided, comprising the following steps: S1 conducts Raman spectroscopy tests on the heterojunction region of suspended graphene / two-dimensional material heterojunction devices at different ambient temperatures, measures the Raman spectra of graphene and two-dimensional materials in suspended graphene / two-dimensional material heterojunction devices at different ambient temperatures, and calibrates the ambient temperature coefficients of graphene and two-dimensional materials through the relationship between the peak position of the Raman spectrum of the suspended graphene / two-dimensional material heterojunction and the ambient temperature; S2 measures the relationship between the Raman spectrum peak shift and the applied voltage in the suspended graphene / two-dimensional material heterojunction device under vacuum, including the graphene Raman spectrum peak and the two-dimensional material Raman spectrum peak shift as the applied voltage changes; S3 calculates the lattice temperature difference of graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device under the set voltage according to the calibrated ambient temperature coefficients of graphene and the two-dimensional material, and the offset of the graphene Raman spectrum peak position and the two-dimensional material Raman spectrum peak position under the set voltage; S4 calculates the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction device at a set voltage based on the lattice temperature difference of graphene and two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at a set voltage, the contact area of ​​the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / two-dimensional material heterojunction device, and the injected electric power value of the suspended graphene / two-dimensional material heterojunction device at a set voltage.

[0016] Preferably, the ambient temperature in S1 ranges from 298.15 K to 500 K. Specifically, S1 is implemented by the following steps: S1.1 Set the initial ambient temperature; S1.2 measure the Raman spectrum peak position of graphene and the Raman spectrum peak position of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at the current ambient temperature; S1.3 updates the current ambient temperature. If the updated ambient temperature is greater than the initial ambient temperature, the process returns to S1.2 to measure the Raman spectrum peak position of graphene and the Raman spectrum peak position of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures; S1.4 Calculate the shift of the peak position of the characteristic peaks of the Raman spectra of graphene and the two-dimensional material as the ambient temperature changes, wherein the peak position shift of the characteristic peak of the graphene Raman spectrum is obtained by subtracting the peak position of the characteristic peak of the graphene Raman spectrum at the initial ambient temperature from the peak position of the characteristic peak of the graphene Raman spectrum after the ambient temperature changes; the peak position shift of the characteristic peak of the two-dimensional material Raman spectrum is obtained by subtracting the peak position of the characteristic peak of the two-dimensional material Raman spectrum at the initial ambient temperature from the peak position of the characteristic peak of the two-dimensional material Raman spectrum after the ambient temperature changes; S1.5 performs linear fitting on the relationship between the peak position shift of the Raman spectrum characteristic peaks of graphene and two-dimensional materials and the change of ambient temperature, and obtains the ambient temperature calibration coefficients of graphene and two-dimensional materials respectively.

[0017] Further, S2 is implemented by the following steps: S2.1 Under vacuum, measure the Raman spectrum peak position of graphene and the Raman spectrum peak position of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device when no voltage is applied; S2.2 Under a set ambient temperature (value range is 298.15K-500 K), a set voltage is applied to the suspended graphene / two-dimensional material heterojunction device, wherein the voltage value range is 0-7V, and the injected electric power value of the suspended graphene / two-dimensional material heterojunction device under the set voltage is measured; the suspended area of ​​the graphene / two-dimensional material heterojunction is selected, and the Raman spectrum peak position of the graphene and the Raman spectrum peak position of the two-dimensional material under the set voltage are measured; S2.3 Calculate the peak position shift of the Raman spectrum characteristic peak of graphene and the peak position shift of the Raman spectrum characteristic peak of the two-dimensional material at the set ambient temperature and the set voltage, wherein the peak position shift of the Raman spectrum characteristic peak of graphene at the set voltage is obtained by subtracting the Raman spectrum peak position of graphene when no voltage is applied from the Raman spectrum peak position of graphene at the set voltage; the peak position shift of the Raman spectrum characteristic peak of the two-dimensional material at the set voltage is obtained by subtracting the Raman spectrum peak position of the two-dimensional material at the set voltage from the Raman spectrum peak position of the two-dimensional material when no voltage is applied.

[0018] In S3, the lattice temperature of graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction at the set voltage is calculated according to the graphene ambient temperature coefficient and the peak position shift of the Raman spectrum characteristic peak of graphene at the set voltage, the two-dimensional material ambient temperature coefficient and the peak position shift of the Raman spectrum characteristic peak of the two-dimensional material at the set voltage, thereby obtaining the lattice temperature difference between the graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction at the set voltage, wherein the lattice temperature of graphene in the suspended graphene / two-dimensional material heterojunction at the set voltage is obtained by dividing the peak position shift of the Raman spectrum characteristic peak of graphene at the set voltage by the ambient temperature calibration coefficient of graphene; the lattice temperature of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction at the set voltage is obtained by dividing the peak position shift of the Raman spectrum characteristic peak of the two-dimensional material at the set voltage by the ambient temperature calibration coefficient of the two-dimensional material.

[0019] Further, S4 is implemented by the following steps: S4.1 Calculation of the contact area between the source and drain electrodes of suspended graphene / 2D material heterojunction devices S ,like Figure 2 shown.

[0020] S4.2 Calculate the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction based on the electric power value of the suspended graphene / two-dimensional material heterojunction device at a set voltage, the contact area of ​​the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / two-dimensional material heterojunction device, and the lattice temperature difference between graphene and two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at a set voltage.

[0021] The method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunction proposed in the present invention fills the gap in the method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunction, and can accurately measure the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunction, which has good application value in the integration and thermal management of suspended graphene / two-dimensional material heterojunction in high-frequency optoelectronic devices and infrared imaging detection devices. Moreover, this method can be extended to the measurement of interfacial thermal conductivity of various suspended two-dimensional material heterojunction systems, which has a great supporting role in the research of interfacial thermal conduction characteristics and thermal management of suspended graphene / two-dimensional material heterojunction.

[0022] Next, Figure 1 and Figure 2 Taking the suspended graphene / hexagonal boron nitride heterojunction device shown as an example, Figure 1 It is a schematic diagram of the structure of a suspended graphene / hexagonal boron nitride heterojunction device; Figure 2The diagram is a schematic diagram of the suspended heterojunction region between the source electrode and the drain electrode of a suspended graphene / hexagonal boron nitride heterojunction device, wherein the electrodes in the device are composed of 5 nanometers thick chromium and 300 nanometers thick gold. The method for measuring the thermal conductivity of the suspended graphene / two-dimensional material heterojunction interface provided by the present invention comprises the following steps: S1 carried out Raman spectroscopy tests on the suspended heterojunction region between the source electrode and the drain electrode of the suspended graphene / hexagonal boron nitride heterojunction device at different ambient temperatures, and measured the peak positions of the graphene Raman spectral characteristic peaks G and 2D peaks in the suspended graphene / hexagonal boron nitride heterojunction device at different ambient temperatures and the hexagonal boron nitride Raman spectral characteristic peaks E. 2g The peak position corresponding to the peak is used to calibrate the ambient temperature coefficient of graphene and hexagonal boron nitride through the relationship between the Raman spectrum peak position of the suspended graphene / hexagonal boron nitride heterojunction and the ambient temperature.

[0023] S1.1 The initial ambient temperature is 23°C (296.15K); S1.2 Measure the peak position corresponding to the characteristic peak G of graphene Raman spectrum at the initial ambient temperature, the peak position corresponding to the characteristic peak 2D of graphene Raman spectrum and the peak position corresponding to the characteristic peak E of hexagonal boron nitride Raman spectrum 2g The peak position value corresponding to the peak.

[0024] S1.3 Increase the ambient temperature to T 1 =300K, 350K, 400K, 425K, 450K, 475K and 500K, respectively, the peak position values ​​corresponding to the characteristic peak G of graphene Raman spectrum, the peak position values ​​corresponding to the characteristic peak 2D of graphene Raman spectrum and the peak position values ​​corresponding to the characteristic peak E of hexagonal boron nitride Raman spectrum at different ambient temperatures were measured. 2g The peak position value corresponding to the peak.

[0025] S1.4 obtained the graphene environmental temperature coefficient corresponding to the graphene Raman spectrum characteristic peak G peak and graphene Raman spectrum characteristic peak 2D peak, and the hexagonal boron nitride Raman spectrum characteristic peak E peak by linear fitting. 2g The peak corresponds to the ambient temperature coefficient of hexagonal boron nitride.

[0026] S2 measures the relationship between the Raman spectrum peak position shift and the applied voltage in the suspended graphene / hexagonal boron nitride heterojunction device under vacuum, including the graphene Raman spectrum peak position and the hexagonal boron nitride Raman spectrum peak position shift with the applied voltage.

[0027] S2.1 In a vacuum environment, measure the peak position corresponding to the graphene Raman spectrum characteristic peak G peak, the peak position corresponding to the Raman spectrum characteristic peak 2D peak and the peak position corresponding to the hexagonal boron nitride Raman spectrum characteristic peak E peak in the suspended graphene / hexagonal boron nitride heterojunction device when no voltage is applied. 2g The peak position value corresponding to the peak.

[0028] S2.2 Under the set ambient temperature, a set voltage is applied to the suspended graphene / hexagonal boron nitride heterojunction device, wherein the voltage range is 0-7V, and the injected electric power value of the suspended graphene / hexagonal boron nitride heterojunction device under the set voltage is measured; the suspended heterojunction region between the source electrode and the drain electrode of the graphene / hexagonal boron nitride heterojunction device is selected, and the peak position value corresponding to the characteristic peak G of the graphene Raman spectrum, the peak position value corresponding to the characteristic peak 2D of the Raman spectrum and the peak position value corresponding to the characteristic peak E of the hexagonal boron nitride Raman spectrum under the set voltage are measured. 2g The peak position value corresponding to the peak; S2.3 Graphene Raman spectral characteristic peak G peak peak shift, 2D peak peak shift and hexagonal boron nitride Raman spectral characteristic peak E peak shift 2g Peak-to-peak shift. The peak-to-peak shift of the characteristic peak G of the Raman spectrum of graphene under the set voltage is obtained by subtracting the peak value corresponding to the characteristic peak G of the Raman spectrum of graphene when the set voltage is applied from the peak value corresponding to the characteristic peak G of the Raman spectrum of graphene when no voltage is applied; the peak-to-peak shift of the characteristic peak 2D of the Raman spectrum of graphene under the set voltage is obtained by subtracting the peak value corresponding to the characteristic peak 2D of the Raman spectrum of graphene when the set voltage is applied from the peak value corresponding to the characteristic peak 2D of the Raman spectrum of graphene when no voltage is applied; the characteristic peak E of the Raman spectrum of hexagonal boron nitride 2g The peak-to-peak shift is determined by the characteristic peak E of the hexagonal boron nitride Raman spectrum when a set voltage is applied. 2g The peak position corresponding to the peak minus the characteristic peak E of the hexagonal boron nitride Raman spectrum when no voltage is applied 2g The peak position corresponding to the peak is obtained.

[0029] S3 calculates the lattice temperature difference of graphene and hexagonal boron nitride in the suspended graphene / hexagonal boron nitride heterojunction device under the set voltage according to the calibrated ambient temperature coefficients of graphene and hexagonal boron nitride, and the offset of the graphene Raman spectrum peak position and the hexagonal boron nitride Raman spectrum peak position under the set voltage, specifically including: According to the ambient temperature coefficient of graphene corresponding to the characteristic peak G of the graphene Raman spectrum and the characteristic peak 2D of the graphene Raman spectrum, and the peak position shift of the characteristic peak G of the graphene Raman spectrum under a set voltage and the peak position shift of the characteristic peak 2D of the graphene Raman spectrum under a set voltage, the lattice temperature of the graphene calculated from the characteristic peak G of the graphene Raman spectrum and the characteristic peak 2D of the graphene Raman spectrum under a set voltage are calculated respectively.

[0030] According to the temperature coefficient of hexagonal boron nitride and the characteristic peak E of the hexagonal boron nitride Raman spectrum under the set voltage 2g The peak-to-peak position shift is used to calculate the lattice temperature of hexagonal boron nitride at a specific voltage.

[0031] The lattice temperature of graphene calculated from the characteristic peak G of the graphene Raman spectrum is obtained by dividing the peak position shift of the characteristic peak G of the graphene Raman spectrum at a set voltage by the environmental temperature coefficient of the graphene calibrated by the characteristic peak G of the graphene Raman spectrum; the lattice temperature of graphene calculated from the characteristic peak 2D of the graphene Raman spectrum is obtained by dividing the peak position shift of the characteristic peak 2D of the graphene Raman spectrum at a set voltage by the environmental temperature coefficient of the graphene calibrated by the characteristic peak 2D of the graphene Raman spectrum; the lattice temperature of hexagonal boron nitride is obtained by dividing the peak position shift of the characteristic peak E of the hexagonal boron nitride Raman spectrum at a set voltage by the environmental temperature coefficient of the graphene. 2g The peak position shift is divided by the characteristic peak E of the hexagonal boron nitride Raman spectrum 2g The ambient temperature coefficient of hexagonal boron nitride was obtained by peak calibration.

[0032] The lattice temperature of graphene calculated from the characteristic peak G of the graphene Raman spectrum is subtracted from the lattice temperature of hexagonal boron nitride to obtain the lattice temperature difference between graphene and hexagonal boron nitride calculated from the characteristic peak G of the graphene Raman spectrum at a set voltage; the lattice temperature of hexagonal boron nitride is subtracted from the lattice temperature of graphene calculated from the characteristic peak 2D of the graphene Raman spectrum to obtain the lattice temperature difference between graphene and hexagonal boron nitride calculated from the characteristic peak 2D of the graphene Raman spectrum at a set voltage.

[0033] S4 measures the contact area of ​​the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / two-dimensional material heterojunction device S ,like Figure 2 According to the injected electric power value of the suspended graphene / hexagonal boron nitride heterojunction device at a set voltage, the contact area S of the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / two-dimensional material heterojunction device, and the lattice temperature difference between graphene and hexagonal boron nitride at a set voltage, the interfacial thermal conductivity of the suspended graphene / hexagonal boron nitride heterojunction device at a set voltage is calculated.

[0034] Matters not covered by the present invention are known technologies.

[0035] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0036] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for measuring thermal conductivity of a suspended graphene / two-dimensional material heterojunction interface, characterized in that: include: S1 determines the suspended graphene / two-dimensional material heterojunction device to be measured, performs Raman spectroscopy tests on the heterojunction region of the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures, measures the Raman spectra of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures, and calibrates the ambient temperature coefficients of graphene and two-dimensional materials through the relationship between the Raman spectral peak positions of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device and the ambient temperature; S2 measures the relationship between the Raman spectrum peak shift and the applied voltage in the suspended graphene / two-dimensional material heterojunction device under vacuum, including the graphene Raman spectrum peak and the two-dimensional material Raman spectrum peak shift as the applied voltage changes; S3 calculates the lattice temperature difference of graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device under the set voltage according to the calibrated ambient temperature coefficients of graphene and the two-dimensional material, and the offset of the graphene Raman spectrum peak position and the two-dimensional material Raman spectrum peak position under the set voltage; S4 calculates the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction device at a set voltage based on the lattice temperature difference of graphene and two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at a set voltage, the contact area of ​​the heterojunction interface of the suspended graphene / two-dimensional material heterojunction device, and the injected electric power value of the suspended graphene / two-dimensional material heterojunction device at a set voltage.

2. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 1, characterized in that: The suspended graphene / two-dimensional material heterojunction device includes a silicon substrate, a silicon dioxide layer, an electrode layer, and a graphene / two-dimensional material heterojunction. The silicon substrate is provided with a silicon dioxide layer, and an electrode layer is arranged on the silicon dioxide layer. The electrode layer includes a source electrode and a drain electrode, which are respectively arranged on the left and right sides above the silicon dioxide layer. The graphene layer and the two-dimensional material layer in the graphene / two-dimensional material heterojunction are arranged in sequence above the electrode layer. The graphene / two-dimensional material heterojunction region between the source electrode and the drain electrode is the suspended region of the graphene / two-dimensional material heterojunction, and the thickness of the source electrode and the drain electrode is the suspended height of the graphene / two-dimensional material heterojunction.

3. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 2, characterized in that: The two-dimensional material includes all two-dimensional materials that can be combined with graphene to form a graphene / two-dimensional material heterojunction, including hexagonal boron nitride, molybdenum disulfide, tungsten disulfide, molybdenum selenide, and tungsten diselenide.

4. The method for measuring thermal conductivity of a suspended graphene / two-dimensional material heterojunction interface according to claim 2 or 3, characterized in that: S1, including: S1.1 Set the initial ambient temperature; S1.2 measure the Raman spectrum peak position of graphene and the Raman spectrum peak position of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at the current ambient temperature; S1.3 updates the current ambient temperature. If the updated ambient temperature is greater than the initial ambient temperature, the process returns to S1.2 to measure the Raman spectrum peak position of graphene and the Raman spectrum peak position of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures; S1.4 Calculate the shift of the peak position of the characteristic peaks of the Raman spectra of graphene and the two-dimensional material as the ambient temperature changes, wherein the peak position shift of the characteristic peak of the graphene Raman spectrum is obtained by subtracting the peak position of the characteristic peak of the graphene Raman spectrum at the initial ambient temperature from the peak position of the characteristic peak of the graphene Raman spectrum after the ambient temperature changes; the peak position shift of the characteristic peak of the two-dimensional material Raman spectrum is obtained by subtracting the peak position of the characteristic peak of the two-dimensional material Raman spectrum at the initial ambient temperature from the peak position of the characteristic peak of the two-dimensional material Raman spectrum after the ambient temperature changes; S1.5 performs linear fitting on the relationship between the peak position shift of the Raman spectrum characteristic peaks of graphene and two-dimensional materials and the change of ambient temperature, and obtains the ambient temperature calibration coefficients of graphene and two-dimensional materials respectively.

5. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 4, characterized in that: The ambient temperature ranges from 298.15K to 500K.

6. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 5, characterized in that: S2, including: S2.1 Under a set ambient temperature, measure the Raman spectrum peak position of graphene and the Raman spectrum peak position of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device when no voltage is applied; S2.2 Under vacuum environment, apply a set voltage to the suspended graphene / two-dimensional material heterojunction device, and measure the injected electric power value of the suspended graphene / two-dimensional material heterojunction device under the set voltage; select the suspended area of ​​the graphene / two-dimensional material heterojunction, and measure the Raman spectrum peak position of the graphene and the Raman spectrum peak position of the two-dimensional material under the set voltage; S2.3 calculates the peak position shift of the Raman spectrum characteristic peak of graphene and the peak position shift of the Raman spectrum characteristic peak of the two-dimensional material under a set voltage.

7. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 6, characterized in that: In S2.3, the peak position shift of the characteristic peak of the Raman spectrum of graphene at a set voltage is obtained by subtracting the Raman spectrum peak position of graphene when no voltage is applied from the Raman spectrum peak position of graphene at the set voltage; the peak position shift of the characteristic peak of the Raman spectrum of the two-dimensional material at a set voltage is obtained by subtracting the Raman spectrum peak position of the two-dimensional material at the set voltage from the Raman spectrum peak position of the two-dimensional material when no voltage is applied.

8. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 5, 6 or 7, characterized in that: In S3, the lattice temperature of graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction at the set voltage is calculated based on the graphene environmental temperature coefficient and the peak position shift of the Raman spectrum characteristic peak of graphene at the set voltage, the two-dimensional material environmental temperature coefficient and the peak position shift of the Raman spectrum characteristic peak of the two-dimensional material at the set voltage, thereby obtaining the lattice temperature difference of graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction at the set voltage.

9. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 8, characterized in that: In S3, the lattice temperature of graphene in the suspended graphene / two-dimensional material heterojunction at a set voltage is obtained by dividing the peak position shift of the Raman spectrum characteristic peak of graphene at the set voltage by the ambient temperature calibration coefficient of graphene; the lattice temperature of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction at a set voltage is obtained by dividing the peak position shift of the Raman spectrum characteristic peak of the two-dimensional material at the set voltage by the ambient temperature calibration coefficient of the two-dimensional material.

10. The method for measuring thermal conductivity of suspended graphene / two-dimensional material heterojunction interface according to claim 9, characterized in that: S4, including: S4.1 Calculate the contact area of ​​the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / two-dimensional material heterojunction device; S4.2 Calculate the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction based on the injected electric power value of the suspended graphene / two-dimensional material heterojunction device at a set voltage, the contact area of ​​the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / two-dimensional material heterojunction device, and the lattice temperature difference between graphene and two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at a set voltage.

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