A method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions

Abstract

The present invention discloses a method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions, which includes four steps: calibrating the environmental temperature coefficients of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device, measuring the peak position offsets of the Raman spectra of graphene and two-dimensional materials under a set voltage, measuring the lattice temperature difference between graphene and two-dimensional materials, and measuring the interfacial thermal conductivity of the heterojunction. The present invention fills the blank of the method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions, can be extended and applied to all suspended heterojunction systems, and meets the measurement requirements of the interfacial thermal conductivity of different types of suspended two-dimensional materials. This method has very important value for the applications of suspended graphene heterojunctions in key fields such as high-frequency electronic devices, infrared optoelectronic detection, and micro-nano electromechanical systems.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of micro-nano semiconductor testing, and particularly to a method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions. Background Art

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

[0003] Suspended graphene can effectively eliminate the effects of wrinkles, carrier scattering, and random doping caused by rough substrates, and has excellent intrinsic physical properties such as massless Dirac fermions, high carrier mobility, high thermal conductivity, and excellent mechanical and thermal stability. This makes it have very important application prospects in key fields such as high-frequency electronic devices and infrared optoelectronic detection. The heterojunction system composed of graphene and two-dimensional materials can effectively regulate the electrical properties of graphene. For example, by covering graphene with hexagonal boron nitride to form a heterojunction structure, graphene can be effectively protected from high-temperature oxidation, enabling the device to withstand a higher current density.

[0004] As the size of transistors gets smaller and the number of internal interfaces increases, there has been no reported method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions. There is an urgent need for a method to accurately measure the interfacial thermal conductivity 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 interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions, which can accurately measure the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions and fill the gap in the method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for measuring the interfacial thermal conductivity of suspended graphene / two-dimensional material heterojunctions, comprising the following steps:

[0008] S1 Determine the suspended graphene / two-dimensional material heterojunction device to be measured, perform Raman spectroscopy tests on the heterojunction region of the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures, measure the Raman spectra of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures, and calibrate the ambient temperature coefficients of graphene and two-dimensional materials based on the variation relationship of the Raman spectral peak positions of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device with the ambient temperature;

[0009] S3 Measure the variation relationship of the Raman spectral peak position shift in the suspended graphene / two-dimensional material heterojunction device with the applied voltage in a vacuum environment, including the shift amounts of the graphene Raman spectral peak position and the two-dimensional material Raman spectral peak position with the applied voltage;

[0010] S3 Calculate the lattice temperature differences of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device under the set voltage respectively according to the ambient temperature coefficients of graphene and two-dimensional materials obtained by calibration and the shift amounts of the graphene Raman spectral peak position and the two-dimensional material Raman spectral peak position under the set voltage;

[0011] S4 Calculate the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction device under the set voltage from the lattice temperature differences of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device under the set voltage, the contact area of the heterojunction interface of the suspended graphene / two-dimensional material heterojunction device, and the injection electric power value of the suspended graphene / two-dimensional material heterojunction device under the set voltage.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The method for measuring the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction provided by the present invention fills the blank of the method for measuring the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction and solves the problem of the absence of a method for measuring the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction.

[0014] The method for measuring the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction provided by the present invention includes four steps: calibrating the ambient temperature coefficients of graphene and two-dimensional materials in the suspended graphene / two-dimensional material heterojunction device, measuring the Raman spectral peak position shift of graphene and two-dimensional materials under the set voltage, measuring the lattice temperature differences of graphene and two-dimensional materials, and the interfacial thermal conductivity. The test steps are simple, highly operable, and can be extended to all suspended heterojunction systems, meeting the needs of measuring the interfacial thermal conductivity of different types of suspended two-dimensional materials. At the same time, it fills the blank of the method for measuring the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0016] Figure 1 It is a schematic structural diagram of a suspended graphene / hexagonal boron nitride heterojunction device in an embodiment;

[0017] Figure 2 It 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 in an embodiment. Detailed implementation manners

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0019] Suspended graphene / two-dimensional material heterojunction devices have good application prospects in high-frequency electronic devices, infrared photodetection, etc., and the heterostructure formed by two-dimensional materials and graphene can effectively regulate the electrical properties of graphene.

[0020] Refer to Figure 1 and Figure 2 , Figure 1 It is a schematic structural diagram of a suspended graphene / hexagonal boron nitride heterojunction device in an embodiment. Figure 2 It 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 in an embodiment. The suspended graphene / two-dimensional material heterojunction device includes a silicon substrate 5, a silicon dioxide layer 4, an electrode layer 3, and a graphene / two-dimensional material heterojunction. The silicon dioxide layer 4 is on the silicon substrate 5, and the electrode layer 3 is provided on the silicon dioxide layer 4. The electrode layer 3 includes a source electrode and a drain electrode, which are respectively arranged on the left and right sides above the silicon dioxide layer 4. 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. 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. 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 gray framed area in Figure 2The medium gray boxed area corresponds to the suspended area of the graphene / 2D material heterojunction.

[0021] The thickness of the electrode layer 3 is the height of the suspension of the graphene / 2D material heterojunction. Figure 2 The area corresponding to the medium gray boxed area is the contact area of the heterojunction interface of the suspended graphene / 2D material heterojunction device, corresponding to the contact area of the suspended heterojunction interface between the source electrode and the drain electrode of the suspended graphene / hBN heterojunction device. S The 2D material includes all 2D materials such as hexagonal boron nitride, molybdenum disulfide, tungsten disulfide, molybdenum selenide, tungsten diselenide, etc. that can form a graphene / 2D material heterojunction with graphene. In this embodiment, the 2D material is hexagonal boron nitride.

[0022] In one embodiment, a method for measuring the interfacial thermal conductivity of a suspended graphene / 2D material heterojunction includes the following steps:

[0023] S1 Conduct Raman spectroscopy tests on the heterojunction region of the suspended graphene / 2D material heterojunction device at different ambient temperatures, measure the Raman spectra of graphene and the 2D material in the suspended graphene / 2D material heterojunction device at different ambient temperatures, and calibrate the ambient temperature coefficients of graphene and the 2D material through the relationship between the Raman spectral peak positions of the suspended graphene / 2D material heterojunction and the ambient temperature.

[0024] S2 In a vacuum environment, measure the relationship between the shift of the Raman spectral peak position in the suspended graphene / 2D material heterojunction device and the applied voltage, including the shift of the Raman spectral peak positions of graphene and the 2D material with the applied voltage.

[0025] S3 According to the calibrated ambient temperature coefficients of graphene and the 2D material, and the shifts of the Raman spectral peak positions of graphene and the 2D material under the action of the set voltage, calculate the lattice temperature differences of graphene and the 2D material in the suspended graphene / 2D material heterojunction device under the set voltage respectively.

[0026] S4 From the lattice temperature differences of graphene and the 2D material in the suspended graphene / 2D material heterojunction device under the set voltage, the contact area of the heterojunction interface between the source electrode and the drain electrode of the suspended graphene / 2D material heterojunction device, and the value of the injected electric power under the set voltage of the suspended graphene / 2D material heterojunction device, calculate the interfacial thermal conductivity of the suspended graphene / 2D material heterojunction device under the set voltage.

[0027] Preferably, the value range of the ambient temperature in S1 is 298.15K - 500 K. Specifically, S1 is implemented through the following steps:

[0028] S1.1 Set the initial ambient temperature;

[0029] S1.2 Measure the Raman spectral peak positions of graphene and the Raman spectral peak positions of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at the current ambient temperature.

[0030] S1.3 Update the current ambient temperature. If the updated ambient temperature is greater than the initial ambient temperature, return to S1.2 to measure the Raman spectral peak positions of graphene and the Raman spectral peak positions of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device at different ambient temperatures.

[0031] S1.4 Calculate the offset of the Raman spectral characteristic peak positions of graphene and the two-dimensional material with respect to the change in ambient temperature. Specifically, the offset of the Raman spectral characteristic peak position of graphene is obtained by subtracting the Raman spectral characteristic peak position value of graphene at the initial ambient temperature from the Raman spectral characteristic peak position value of graphene after the change in ambient temperature; the offset of the Raman spectral characteristic peak position of the two-dimensional material is obtained by subtracting the Raman spectral characteristic peak position value of the two-dimensional material at the initial ambient temperature from the Raman spectral characteristic peak position value of the two-dimensional material after the change in ambient temperature.

[0032] S1.5 Perform a linear fit on the relationship between the offset of the Raman spectral characteristic peak positions of graphene and the two-dimensional material and the change in ambient temperature to obtain the ambient temperature calibration coefficients of graphene and the two-dimensional material respectively.

[0033] Furthermore, S2 is implemented through the following steps:

[0034] S2.1 In a vacuum environment, measure the Raman spectral peak positions of graphene and the Raman spectral peak positions of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device without applying a voltage.

[0035] S2.2 At a set ambient temperature (the value range is 298.15K - 500 K), apply a set voltage to the suspended graphene / two-dimensional material heterojunction device, where the voltage value range is 0 - 7V, 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 spectral peak positions of graphene and the Raman spectral peak positions of the two-dimensional material under the set voltage.

[0036] S2.3 Calculate the offset of the Raman spectral characteristic peak positions of graphene and the offset of the Raman spectral characteristic peak positions of the two-dimensional material under the set voltage at the set ambient temperature. Specifically, the offset of the Raman spectral characteristic peak position of graphene under the set voltage is obtained by subtracting the Raman spectral peak position of graphene without applying a voltage from the Raman spectral peak position of graphene under the set voltage; the offset of the Raman spectral characteristic peak position of the two-dimensional material under the set voltage is obtained by subtracting the Raman spectral peak position of the two-dimensional material without applying a voltage from the Raman spectral peak position of the two-dimensional material under the set voltage.

[0037] In S3, according to the graphene environmental temperature coefficient, the peak position shift of the Raman spectral characteristic peak of graphene under the set voltage, the two-dimensional material environmental temperature coefficient, and the peak position shift of the Raman spectral characteristic peak of the two-dimensional material under the set voltage, the lattice temperatures of graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction under the set voltage are calculated, and thus the lattice temperature difference between graphene and the two-dimensional material in the suspended graphene / two-dimensional material heterojunction under the set voltage is obtained. The lattice temperature of graphene in the suspended graphene / two-dimensional material heterojunction under the set voltage is obtained by dividing the peak position shift of the Raman spectral characteristic peak of graphene under the set voltage by the environmental temperature calibration coefficient of graphene; the lattice temperature of the two-dimensional material in the suspended graphene / two-dimensional material heterojunction under the set voltage is obtained by dividing the peak position shift of the Raman spectral characteristic peak of the two-dimensional material under the set voltage by the environmental temperature calibration coefficient of the two-dimensional material.

[0038] Further, S4 is implemented through the following steps: including:

[0039] S4.1 Measure 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 , as Figure 2 shown.

[0040] S4.2 Calculate the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction according to the electric power value of the suspended graphene / two-dimensional material heterojunction device under the 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 the two-dimensional material in the suspended graphene / two-dimensional material heterojunction device under the set voltage.

[0041] The method for measuring the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction proposed by the present invention fills the blank of the method for measuring the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction, can accurately measure the interfacial thermal conductivity of the suspended graphene / two-dimensional material heterojunction, and has good application value in the integration and thermal management of the 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 the interfacial thermal conductivity of various suspended two-dimensional material heterojunction systems, and has a great supporting role in the research on the interfacial heat conduction characteristics and thermal management of the suspended graphene / two-dimensional material heterojunction.

[0042] Next, taking the suspended graphene / hexagonal boron nitride heterojunction device shown in Figure 1 and Figure 2 as an example, Figure 1 is the structural schematic diagram of the suspended graphene / hexagonal boron nitride heterojunction device; Figure 2Schematic diagram of the suspended heterojunction region between the source and drain electrodes of a suspended graphene / hexagonal boron nitride heterojunction device. The electrodes in this device are composed of 5-nanometer-thick chromium and 300-nanometer-thick gold. The method for measuring the interfacial thermal conductivity of a suspended graphene / two-dimensional material heterojunction provided by the present invention includes the following steps:

[0043] S1 Conduct Raman spectroscopy tests on the suspended heterojunction region between the source and drain electrodes of the suspended graphene / hexagonal boron nitride heterojunction device at different ambient temperatures, and measure the peak positions of the characteristic peaks G peak and 2D peak of the graphene Raman spectrum and the characteristic peak E of the hexagonal boron nitride Raman spectrum in the suspended graphene / hexagonal boron nitride heterojunction device at different ambient temperatures. Calibrate the ambient temperature coefficients of graphene and hexagonal boron nitride based on the relationship between the Raman spectrum peak positions of the suspended graphene / hexagonal boron nitride heterojunction and the ambient temperature. 2g The peak position of the corresponding peak.

[0044] S1.1 The initial ambient temperature is 23 °C (296.15 K);

[0045] S1.2 Measure the peak position value of the characteristic peak G peak of the graphene Raman spectrum, the peak position value of the characteristic peak 2D peak of the graphene Raman spectrum, and the characteristic peak E of the hexagonal boron nitride Raman spectrum at the initial ambient temperature. 2g The peak position value of the corresponding peak.

[0046] S1.3 Increase the ambient temperature to T1 = 300 K, 350 K, 400 K, 425 K, 450 K, 475 K, and 500 K respectively, and measure the peak position values of the characteristic peak G peak of the graphene Raman spectrum, the peak position values of the characteristic peak 2D peak of the graphene Raman spectrum, and the characteristic peak E of the hexagonal boron nitride Raman spectrum at different ambient temperatures. 2g The peak position value of the corresponding peak.

[0047] S1.4 Through linear fitting, obtain the ambient temperature coefficients of graphene corresponding to the characteristic peak G peak of the graphene Raman spectrum and the characteristic peak 2D peak of the graphene Raman spectrum, and the ambient temperature coefficient of hexagonal boron nitride corresponding to the characteristic peak E of the hexagonal boron nitride Raman spectrum respectively. 2g The peak position of the corresponding peak.

[0048] S2 In a vacuum environment, measure the relationship between the shift of the Raman spectrum peak position and the applied voltage in the suspended graphene / hexagonal boron nitride heterojunction device, including the shift of the graphene Raman spectrum peak position and the hexagonal boron nitride Raman spectrum peak position with the applied voltage.

[0049] S2.1 In a vacuum environment, measure the peak position value of the characteristic peak G peak of the graphene Raman spectrum, the peak position value of the characteristic peak 2D peak of the Raman spectrum, and the characteristic peak E of the hexagonal boron nitride Raman spectrum in the suspended graphene / hexagonal boron nitride heterojunction device when no voltage is applied.2g The peak position value corresponding to the peak.

[0050] S2.2 At a set environmental temperature, apply a set voltage to the suspended graphene / hexagonal boron nitride heterojunction device, where the voltage range is 0 - 7V, and measure the injection electric power value of the suspended graphene / hexagonal boron nitride heterojunction device under the set voltage; select the suspended heterojunction region between the source electrode and the drain electrode of the graphene / hexagonal boron nitride heterojunction device, and measure the peak position value corresponding to the G peak of the graphene Raman spectral characteristic peak, the peak position value corresponding to the 2D peak of the Raman spectral characteristic peak, and the E peak of the hexagonal boron nitride Raman spectral characteristic peak under the set voltage. 2g The peak position value corresponding to the peak;

[0051] S2.3 The peak position offset of the G peak of the graphene Raman spectral characteristic peak, the peak position offset of the 2D peak, and the E peak of the hexagonal boron nitride Raman spectral characteristic peak. Among them, the peak position offset of the G peak of the graphene Raman spectral characteristic peak under the set voltage is obtained by subtracting the peak position value corresponding to the G peak of the graphene Raman spectral characteristic peak when no voltage is applied from the peak position value corresponding to the G peak of the graphene Raman spectral characteristic peak when the set voltage is applied; the peak position offset of the 2D peak of the graphene Raman spectral characteristic peak under the set voltage is obtained by subtracting the peak position value corresponding to the 2D peak of the graphene Raman spectral characteristic peak when no voltage is applied from the peak position value corresponding to the 2D peak of the graphene Raman spectral characteristic peak when the set voltage is applied; the peak position offset of the E peak of the hexagonal boron nitride Raman spectral characteristic peak is obtained by subtracting the peak position value corresponding to the E peak of the hexagonal boron nitride Raman spectral characteristic peak when no voltage is applied from the peak position value corresponding to the E peak of the hexagonal boron nitride Raman spectral characteristic peak when the set voltage is applied. 2g The peak position offset of the peak. Among them, the peak position offset of the G peak of the graphene Raman spectral characteristic peak under the set voltage is obtained by subtracting the peak position value corresponding to the G peak of the graphene Raman spectral characteristic peak when no voltage is applied from the peak position value corresponding to the G peak of the graphene Raman spectral characteristic peak when the set voltage is applied; the peak position offset of the 2D peak of the graphene Raman spectral characteristic peak under the set voltage is obtained by subtracting the peak position value corresponding to the 2D peak of the graphene Raman spectral characteristic peak when no voltage is applied from the peak position value corresponding to the 2D peak of the graphene Raman spectral characteristic peak when the set voltage is applied; the peak position offset of the E peak of the hexagonal boron nitride Raman spectral characteristic peak is obtained by subtracting the peak position value corresponding to the E peak of the hexagonal boron nitride Raman spectral characteristic peak when no voltage is applied from the peak position value corresponding to the E peak of the hexagonal boron nitride Raman spectral characteristic peak when the set voltage is applied. 2g The peak position offset of the E peak of the hexagonal boron nitride Raman spectral characteristic peak when the set voltage is applied. 2g The peak position value corresponding to the peak of the hexagonal boron nitride Raman spectral characteristic peak when no voltage is applied. 2g The peak position value corresponding to the peak is obtained.

[0052] S3 According to the environmental temperature coefficients of graphene and hexagonal boron nitride obtained by calibration and the offset of the graphene Raman spectral peak position and the hexagonal boron nitride Raman spectral peak position under the set voltage, calculate the lattice temperature difference between graphene and hexagonal boron nitride in the suspended graphene / hexagonal boron nitride heterojunction device under the set voltage, specifically including:

[0053] According to the environmental temperature coefficients of graphene corresponding to the G peak of the graphene Raman spectral characteristic peak and the 2D peak of the graphene Raman spectral characteristic peak, and the peak position offset of the G peak of the graphene Raman spectral characteristic peak under the set voltage and the peak position offset of the 2D peak of the graphene Raman spectral characteristic peak under the set voltage, calculate the lattice temperature of graphene calculated from the G peak of the graphene Raman spectral characteristic peak and the 2D peak of the graphene Raman spectral characteristic peak under the set voltage respectively.

[0054] According to the boron nitride temperature coefficient and the E peak of the hexagonal boron nitride Raman spectral characteristic peak under the set voltage. 2gThe peak position offset is used to calculate the lattice temperature of hexagonal boron nitride at a specific voltage.

[0055] Among them, the lattice temperature of graphene calculated from the G peak of the Raman spectrum characteristic peak of graphene is obtained by dividing the peak position offset of the G peak of the Raman spectrum characteristic peak of graphene under the set voltage by the environmental temperature coefficient of graphene calibrated by the G peak of the Raman spectrum characteristic peak of graphene; the lattice temperature of graphene calculated from the 2D peak of the Raman spectrum characteristic peak of graphene is obtained by dividing the peak position offset of the 2D peak of the Raman spectrum characteristic peak of graphene under the set voltage by the environmental temperature coefficient of graphene calibrated by the 2D peak of the Raman spectrum characteristic peak of graphene; the lattice temperature of hexagonal boron nitride is obtained by dividing the peak-to-peak position offset of the E 2g peak of the Raman spectrum characteristic peak of hexagonal boron nitride under the set voltage by the environmental temperature coefficient of hexagonal boron nitride calibrated by the E 2g peak of the Raman spectrum characteristic peak of hexagonal boron nitride.

[0056] Subtract the lattice temperature of hexagonal boron nitride from the lattice temperature of graphene calculated from the G peak of the Raman spectrum characteristic peak of graphene to obtain the lattice temperature difference between graphene and hexagonal boron nitride calculated from the G peak of the Raman spectrum characteristic peak of graphene under the set voltage; subtract the lattice temperature of hexagonal boron nitride from the lattice temperature of graphene calculated from the 2D peak of the Raman spectrum characteristic peak of graphene to obtain the lattice temperature difference between graphene and hexagonal boron nitride calculated from the 2D peak of the Raman spectrum characteristic peak of graphene under the set voltage.

[0057] 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 , as Figure 2 shown. According to the injection electric power value under the set voltage of the suspended graphene / hexagonal boron nitride heterojunction device, 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 under the set voltage, the interfacial thermal conductivity of the suspended graphene / hexagonal boron nitride heterojunction device under the set voltage is calculated.

[0058] Matters not covered by the present invention are well-known technologies.

[0059] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered as the scope described in this specification.

[0060] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

[0061] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within 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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