Suspended low-dimensional material and preparation method thereof

Abstract

The embodiment of the invention provides a preparation method of a suspended low-dimensional material. The preparation method comprises the following steps: preparing a low-dimensional material with a supporting material layer and an organic thin film layer; transferring the low-dimensional material with the support material layer and the organic thin film layer to a suspended structure; and stripping the support material layer to prepare the suspended low-dimensional material. According to the preparation method of the suspended low-dimensional material provided by the embodiment of the invention, the suspended sample can be efficiently and controllably prepared without pollution, and the suspended low-dimensional material is suitable for tests of a transmission electron microscope, a Raman spectrum, nonlinear optics and the like. The embodiment of the invention further provides the suspended low-dimensional material.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor material technology, and in particular, relates to a suspended low-dimensional material and a preparation method thereof. Background Art

[0002] With the rapid development of new materials and nanotechnology, low-dimensional materials such as one-dimensional nanowires and two-dimensional materials have become a hot topic of research due to their excellent physical and electrical properties, and have shown broad application prospects in electronics, optics and quantum devices. However, the preparation and transfer of low-dimensional materials still face many challenges, especially the properties of the samples themselves are rarely studied.

[0003] Due to the properties of low-dimensional materials, the interface will have a significant impact on the sample, making it difficult to study its intrinsic material properties. Therefore, the preparation of suspended low-dimensional materials has become a prerequisite for studying the intrinsic properties of the sample. Existing low-dimensional material transfer technologies have certain limitations, especially in the preparation and application of suspended structures. For example, traditional wet etching, dry stripping and physical stripping methods may cause damage, contamination or introduce structural defects in low-dimensional materials, thereby affecting device performance. In addition, how to maintain the integrity and surface cleanliness of low-dimensional materials during the transfer process, especially in applications in precision tests such as transmission electron microscopy (TEM), Raman spectroscopy and nonlinear optics, remains a technical problem that needs to be solved urgently. Summary of the invention

[0004] In response to the problems existing in the above-mentioned related technologies, the present invention provides a suspended low-dimensional material and a preparation method thereof, which can prepare suspended samples efficiently, pollution-free and controllably, and is suitable for tests such as transmission electron microscopy, Raman spectroscopy and nonlinear optics.

[0005] In a first aspect, the present application provides a method for preparing a suspended low-dimensional material, comprising the following steps:

[0006] preparing a low-dimensional material having a support material layer and a porous organic thin film layer;

[0007] transferring the low-dimensional material with the support material layer and the porous organic thin film layer to a suspended structure; and

[0008] The supporting material layer is peeled off to prepare the suspended low-dimensional material.

[0009] Furthermore, the preparation of the low-dimensional material with a support material layer and an organic thin film layer comprises:

[0010] preparing the low-dimensional material on a substrate;

[0011] preparing and peeling off the porous organic thin film layer on the substrate;

[0012] sequentially laminating the porous organic film layer and the supporting material layer on the low-dimensional material; and

[0013] The low-dimensional material attached with the porous organic thin film layer and the supporting material layer is peeled off from the substrate.

[0014] Furthermore, the low-dimensional material is formed by combining the first low-dimensional material and the second low-dimensional material, and the preparation of the low-dimensional material with the support material layer and the porous organic thin film layer comprises:

[0015] Prepare the first low-dimensional material to be bonded to the support material layer and the porous organic thin film layer;

[0016] preparing the second low-dimensional material on a substrate;

[0017] Laminating the first low-dimensional material with the support material layer and the porous thin film layer on the second low-dimensional material to form a heterojunction between the first low-dimensional material and the second low-dimensional material;

[0018] The substrate is peeled off to prepare the low-dimensional material with the support material layer and the porous organic thin film layer.

[0019] Furthermore, the step of preparing the low-dimensional material on a substrate comprises:

[0020] The low-dimensional material is formed on the substrate by mechanical exfoliation or chemical vapor deposition.

[0021] Furthermore, the step of preparing and peeling off the porous organic thin film layer on the substrate comprises:

[0022] Coating an organic thin film layer on the substrate, and forming holes in the organic thin film layer by electron beam etching or photolithography to form the organic thin film layer with holes; and

[0023] The holey organic thin film layer is peeled off from the substrate.

[0024] Furthermore, the porous organic film layer is a PMMA film or a polystyrene film, and the thickness of the porous organic film layer is between 100 nanometers and 5 micrometers.

[0025] Furthermore, the support material layer is made of PDMS, and the thickness of the support material layer is between 0.4 mm and 3 mm.

[0026] Furthermore, the low-dimensional material includes one-dimensional material and / or two-dimensional material, the one-dimensional material is carbon nanotube, silicon nanowire or silver nanowire, and the two-dimensional material is graphene, molybdenum disulfide, boron nitride or black phosphorus.

[0027] Furthermore, the substrate or the base is made of silicon, silicon oxide or sapphire.

[0028] In a second aspect, an embodiment of the present application provides a suspended low-dimensional material, characterized in that the suspended low-dimensional material is made by any of the methods described above.

[0029] In the preparation method of suspended low-dimensional materials provided in the embodiment of the present application, the supporting material layer provides stable support for the transfer of low-dimensional materials, and the perforated organic film layer can ensure that the suspended structure or the hole structure is suitable for the transfer of suspended low-dimensional materials. Therefore, the preparation method of suspended low-dimensional materials provided in the embodiment of the present application can efficiently transfer the sample to the suspended structure or the hole structure while ensuring the integrity of the low-dimensional material or sample, and obtain a clean suspended sample by removing the supporting material layer, thereby simplifying the process flow, having the advantages of pollution-free, low-loss, and controllable angle transfer, and can be used for high-precision tests such as transmission electron microscopy, Raman spectroscopy, and nonlinear optical experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0031] Figure 1 A schematic diagram of a process for preparing a suspended low-dimensional material provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the actual operation of the method for preparing the suspended low-dimensional material provided in Example 1 of the present application;

[0033] Figure 3a and Figure 3b An optical image of a suspended low-dimensional material involved in the method for preparing a suspended low-dimensional material provided in Example 1 of the present application;

[0034] Figure 4 TEM image and Fourier transform image of the suspended low-dimensional material involved in the preparation method of the suspended low-dimensional material provided in Example 1 of the present application;

[0035] Figure 5 An optical image and schematic diagram of a suspended low-dimensional material involved in the method for preparing a suspended low-dimensional material provided in Example 2 of the present application;

[0036] Figure 6TEM image and Fourier transform image of the suspended low-dimensional material involved in the preparation method of the suspended low-dimensional material provided in Example 2 of the present application;

[0037] Figure 7a and Figure 7b An optical image of a suspended low-dimensional material involved in the method for preparing a suspended low-dimensional material provided in Example 3 of the present application;

[0038] Figure 8 This is a schematic diagram of the actual operation of the method for preparing suspended low-dimensional materials provided in Example 4 of the present application.

[0039] Fig. 9 An optical image of a suspended low-dimensional material involved in the method for preparing a suspended low-dimensional material provided in Example 4 of the present application;

[0040] Fig.10 TEM images, Fourier transform images, and corresponding Raman spectrum diagrams and nonlinear optical spectrum diagrams of the suspended low-dimensional materials involved in the preparation method of the suspended low-dimensional materials provided in Example 4 of the present application.

[0041] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0044] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, the singular forms of "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0045] Therefore, see Figure 1The present application embodiment provides a method for preparing a suspended low-dimensional material, comprising the following steps:

[0046] S101: preparing a low-dimensional material having a support material layer and a porous organic thin film layer;

[0047] S102: transferring the low-dimensional material with the support material layer and the porous organic thin film layer to a suspended structure; and

[0048] S103: Peeling off the support material layer to prepare the suspended low-dimensional material.

[0049] Compared with the existing preparation methods, in the preparation method of suspended low-dimensional materials provided in the embodiment of the present application, the supporting material layer provides stable support for the transfer of low-dimensional materials, and the porous organic film layer can ensure that the suspended structure or the hole structure is suitable for the transfer of suspended low-dimensional materials. Therefore, the preparation method of suspended low-dimensional materials provided in the embodiment of the present application can efficiently transfer the sample to the suspended structure or the hole structure while ensuring the integrity of the low-dimensional material or sample, and obtain a clean suspended sample by removing the supporting material layer, thereby simplifying the process flow, and has the advantages of pollution-free, low-loss, and controllable angle transfer, and can be used for high-precision tests such as transmission electron microscopy (TEM), Raman spectroscopy and nonlinear optical experiments.

[0050] Further, refer to Figures 2 to 7b In some embodiments of the present application, the step of preparing a low-dimensional material having a support material layer and a porous organic thin film layer comprises:

[0051] preparing the low-dimensional material on a substrate;

[0052] preparing and peeling off the porous organic thin film layer on the substrate;

[0053] sequentially laminating the porous organic film layer and the supporting material layer on the low-dimensional material; and

[0054] The low-dimensional material attached with the porous organic thin film layer and the supporting material layer is peeled off from the substrate.

[0055] As described above, the supporting material layer provides stable support for the transfer of the low-dimensional material, the porous organic film layer can ensure that the suspended structure or hole structure is suitable for the transfer of the suspended low-dimensional material, and the low-dimensional material with the supporting material layer and the porous organic film layer is prepared through the above steps, and the preparation process is simple and efficient.

[0056] Further, refer to Figure 8In some embodiments of the present application, the low-dimensional material is formed by combining the first low-dimensional material and the second low-dimensional material, and the preparation of the low-dimensional material with the support material layer and the porous organic thin film layer comprises the following steps:

[0057] Prepare the first low-dimensional material to be bonded to the support material layer and the porous organic thin film layer;

[0058] preparing the second low-dimensional material on a substrate;

[0059] Laminating the first low-dimensional material with the support material layer and the porous organic thin film layer on the second low-dimensional material to form a heterojunction between the first low-dimensional material and the second low-dimensional material;

[0060] The substrate is peeled off to prepare the low-dimensional material with the support material layer and the porous organic thin film layer.

[0061] Specifically, the preparation method of suspended low-dimensional materials provided in the embodiments of the present application is also applicable to the situation of low-dimensional material heterojunction transfer. For example, when the low-dimensional material is formed by combining a first low-dimensional material and a second low-dimensional material, when the first low-dimensional material and the second low-dimensional material are bonded, a heterojunction structure will be generated. The preparation or transfer method of suspended low-dimensional material heterojunction provided in the embodiments of the present application can efficiently transfer the sample to a suspended structure or a hole structure while ensuring the integrity of the low-dimensional material or sample, and obtain a clean suspended sample by removing the supporting material layer, thereby simplifying the process flow, having the advantages of pollution-free, low-loss, and controllable angle transfer, and can be used for high-precision tests such as transmission electron microscopy, Raman spectroscopy, and nonlinear optical experiments.

[0062] It can be understood that the above only uses two low-dimensional materials as examples to illustrate the preparation method of the suspended low-dimensional material involved in the embodiment of the present application, and the preparation method of the suspended low-dimensional material involved in the embodiment of the present application can also be applied to the case of triple, quadruple or more low-dimensional materials. Multiple superlattices or heterojunction structures can be formed at the interfaces of the multiple low-dimensional materials. The preparation method of the multiple low-dimensional materials can be constructed with reference to the process steps discussed in the above examples.

[0063] Further, in some embodiments of the present application, the step of preparing the low-dimensional material on a substrate comprises:

[0064] The low-dimensional material is formed on the substrate by mechanical exfoliation or chemical vapor deposition.

[0065] Specifically, the mechanical stripping method is to use mechanical force to physically strip the low-dimensional material from the substrate, while the chemical vapor deposition method is to use gas phase compounds or single substances of low-dimensional materials containing film elements to chemically react on the surface of the substrate to generate a thin film. In the preparation method of the suspended low-dimensional material provided in the embodiment of the present application, the low-dimensional material is formed on the substrate by mechanical stripping or chemical vapor deposition, and the production process is simple and the production cost is low.

[0066] Further, in some embodiments of the present application, the step of preparing and peeling off the porous organic thin film layer on the substrate includes:

[0067] Coating an organic thin film layer on the substrate, and forming holes in the organic thin film layer by electron beam etching or photolithography to form the organic thin film layer with holes; and

[0068] The holey organic thin film layer is peeled off from the substrate.

[0069] As described above, the preparation method of suspended low-dimensional materials provided in the embodiment of the present application manufactures a perforated organic thin film layer through the above process, which can ensure that the suspended structure or hole structure is suitable for the transfer of suspended low-dimensional materials, thereby efficiently transferring the sample to the suspended structure or hole structure.

[0070] Furthermore, in some embodiments of the present application, the porous organic film layer is a PMMA film or a polystyrene film, and the thickness of the porous organic film layer is between 100 nanometers and 5 micrometers.

[0071] Specifically, PMMA (Polymethyl Methacrylate) film is a polymer film with the characteristics of high transparency, good mechanical strength and strong weather resistance. Polystyrene film is a film material made of polymer material polystyrene (PS) with good light transmittance and mechanical properties. The thickness of the porous organic film layer is between 100 nanometers and 5 microns, thereby ensuring that the low-dimensional material can be stably transferred to the suspended structure or hole structure.

[0072] Furthermore, in some embodiments of the present application, the support material layer is made of PDMS (Polydimethylsiloxane), and the thickness of the support material layer is between 0.4 mm and 3 mm.

[0073] Specifically, PDMS is a polymer compound with many unique physical and chemical properties, such as hydrophobicity, air permeability, chemical stability, physiological inertness, etc. As mentioned above, the support material layer is made of PDMS, and the thickness of the support material layer is between 0.4 mm and 3 mm, so that it can provide stable support for the transfer of low-dimensional materials, and then on the basis of ensuring the integrity of low-dimensional materials or samples, the samples can be efficiently transferred to suspended structures or hole structures, and clean suspended samples can be obtained by removing the support material layer.

[0074] Furthermore, in some embodiments of the present application, the low-dimensional material includes one-dimensional material and / or two-dimensional material, the one-dimensional material is carbon nanotube, silicon nanowire or silver nanowire, and the two-dimensional material is graphene, molybdenum disulfide, boron nitride or black phosphorus.

[0075] Specifically, one-dimensional materials refer to materials in which at least one dimension is within the nanoscale range, and its length can be much larger than its diameter or thickness, while the other two dimensions (width and height) remain at the nanoscale or smaller. Due to their unique size and structural characteristics, these materials exhibit physical and chemical properties that are completely different from conventional materials. One-dimensional materials include carbon nanotubes, silicon nanowires, or silver nanowires.

[0076] Two-dimensional materials refer to materials in which electrons can only move freely (planar motion) in two dimensions at a non-nanoscale (1 to 100 nm). Two-dimensional materials are usually graphene, molybdenum disulfide, boron nitride or black phosphorus.

[0077] Furthermore, in some embodiments of the present application, the substrate or the base is made of silicon, silicon oxide or sapphire, so as to ensure that low-dimensional materials or organic films can be stably prepared thereon.

[0078] Hereinafter, Examples 1 to 4 describe in detail the preparation method of the suspended low-dimensional material provided in the embodiments of the present application according to different situations:

[0079] Embodiment 1

[0080] Reference Figures 2 to 4 The first embodiment of the present application is applicable to the situation where the substrate is 1×1 cm 2 The silicon / silicon oxide, the low-dimensional material is graphene, and the target substrate is a copper micro-gate. Therefore, the specific steps of the preparation method of the two-dimensional material provided in the embodiment of the present application are:

[0081] (1) 1×1cm 2 Using silicon / silicon oxide as a substrate, a graphene film is obtained by exfoliation to obtain a graphene single layer or a few layers of film, and its integrity and uniformity are ensured;

[0082] (2) 1×1cm2 The sapphire surface is coated with an organic film PMMA and dried in a hot table or oven to form an organic film layer. Figure 2 As shown in FIG. 1 , the desired hole pattern is engraved on the PMMA film using electron beam etching (Electron-blocking Layer, EBL) technology. Figure 2 It can be seen that a PMMA film with holes is formed;

[0083] (3) PDMS is applied to the porous PMMA film and peeled off from the sapphire surface by conventional dry peeling or wet etching to obtain an independent porous PMMA film structure;

[0084] (4) Use a micro-alignment system to align the PDMS / porous PMMA film with the graphene film and ensure that the two are flatly attached. Then, peel the PDMS / porous PMMA film / graphene film from the silicon / silicon oxide to obtain a PDMS / porous PMMA-graphene sample;

[0085] (5) The PDMS / porous PMMA-graphene sample obtained in step 4 is attached to the pre-prepared copper micro-grid and heated at 80 degrees Celsius to ensure that the graphene and the copper micro-grid are closely attached to each other, thereby obtaining a suspended graphene film. Figure 3a , Figure 3b and Figure 4 As shown, the obtained free-standing graphene film can be used for TEM characterization.

[0086] Embodiment 2

[0087] Reference Figure 5 and Figure 6 The second embodiment of the present application is applicable to the situation where the base is 0.5×0.5 cm 2 The silicon / silicon oxide, the low-dimensional material is graphene, and the target substrate is a copper micro-gate. Therefore, the specific steps of the preparation method of the two-dimensional material provided in the embodiment of the present application are:

[0088] (1) 0.5×0.5cm 2 Silicon / silicon oxide is used as the substrate, and MoS2 film is obtained by exfoliation method to ensure its integrity and uniformity to obtain graphene monolayer or few-layer film;

[0089] (2) Empty 1×1cm 2 The sapphire surface is coated with an organic film PMMA and dried in a hot table or oven to form an organic film layer. Figure 5 As shown, the desired hole pattern is engraved on the PMMA film using electron beam etching technology to form a PMMA film with holes;

[0090] (3) PDMS is applied to the porous PMMA film and peeled off from the sapphire surface by conventional dry stripping or wet etching to obtain the following Figure 5 The PMMA film structure with holes shown;

[0091] (4) Use the micro-alignment system to align the PDMS / porous PMMA film. Figure 5 As shown, the MoS2 film and the two are ensured to be flat and even. Figure 5 As shown, the PDMS / porous PMMA film / graphene film is peeled off from silicon / silicon oxide to obtain a PDMS / porous PMMA-MoS2 sample;

[0092] (5) The PDMS / porous PMMA-MoS2 sample obtained in step 4 is attached to the pre-prepared copper micro-grid, and then heated at 80 degrees Celsius to ensure that the MoS2 and the copper micro-grid are closely attached to each other, thereby obtaining a suspended graphene film. Figure 6 As shown, the obtained free-standing graphene film can be used for TEM characterization.

[0093] Embodiment 3

[0094] Reference Figure 7a and Figure 7b The third embodiment of the present application is applicable to the following situations: the substrate is 1×1 cm 2 The silicon / silicon oxide, the low-dimensional material is graphene, and the target substrate is a copper micro-gate. Therefore, the specific steps of the preparation method of the two-dimensional material provided in the embodiment of the present application are:

[0095] (1) 1×1cm 2 Silicon / silicon oxide is used as a substrate to obtain graphene by exfoliation method, and then it is transformed into one-dimensional graphene nanoscrolls by solution method;

[0096] (2) Empty 1×1cm 2 The organic film PMMA is coated on the SiO2 surface and dried in a hot table or oven to form an organic film layer, and a layer of photoresist is spin-coated on it and dried. The desired hole pattern is engraved on the photoresist / PMMA film using ultraviolet lithography technology, and the hole structure on the PMMA is punched through with oxygen plasma to form a photoresist / PMMA film with holes;

[0097] (3) applying PDMS onto the photoresist / PMMA film with holes, and peeling it off from the sapphire surface by conventional dry stripping or wet etching transfer methods to obtain an independent photoresist / PMMA film structure with holes;

[0098] (4) Use a micro-alignment system to align the PDMS / porous photoresist / PMMA film with the graphene film and ensure that the two are flat and aligned. Figure 7a As shown, PDMS / porous photoresist / PMMA film / graphene nanoscroll is peeled off from silicon / silicon oxide to obtain a PDMS / porous photoresist / PMMA-graphene nanoscroll sample;

[0099] (5) Attach the PDMS / porous PMMA-graphene nanoscroll sample obtained in step 4 to the pre-prepared copper micro-grid to obtain a suspended graphene film. Figure 7b As shown, the obtained free-standing graphene film can be used for TEM characterization.

[0100] Embodiment 4

[0101] Reference Figures 9 and 10 The fourth embodiment of the present application is applicable to the situation where the low-dimensional material is a combination of WS2 / MoS2. Therefore, the specific steps of the preparation method of the two-dimensional material provided in the embodiment of the present application are: (1) preparing a PDMS / porous PMMA-MoS2 sample; (2) preparing a WS2 sample on a substrate; (3) bonding the PDMS / porous PMMA-MoS2 sample to the WS2 sample to form a heterojunction between the MoS2 sample and the WS2 sample; (4) peeling off the substrate to prepare a PDMS / porous PMMA-WS2 / MoS2 sample; (5) attaching the PDMS / porous PMMA-WS2 / MoS2 sample obtained in step 4 to a pre-prepared copper micro-gate to obtain a suspended WS2 / MoS2 film. Therefore, the present application provides a method for preparing or transferring a suspended low-dimensional material heterojunction according to the fourth embodiment, which can efficiently transfer the sample to a suspended structure or a hole structure while ensuring the integrity of the low-dimensional material or sample, and obtain a clean suspended sample by removing the supporting material layer, thereby simplifying the process flow and having the advantages of no pollution, low loss, and controllable angle transfer, such as Fig.10 As shown, the obtained suspended WS2 / MoS2 film can be used for high-precision tests such as transmission electron microscopy, Raman spectroscopy and nonlinear optical experiments.

[0102] The present application also provides a suspended low-dimensional material, which is made by the method described above. The specific preparation method of the suspended low-dimensional material refers to the above embodiment. Since the specific preparation method of the suspended low-dimensional material adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0103] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for preparing a suspended low-dimensional material, characterized in that: The following steps are involved: preparing a low-dimensional material having a support material layer and a porous organic thin film layer; transferring the low-dimensional material with the support material layer and the porous organic thin film layer onto a suspended structure; and The supporting material layer is peeled off to prepare the suspended low-dimensional material.

2. The method according to claim 1, characterized in that The method for preparing a low-dimensional material having a support material layer and a porous organic thin film layer comprises: preparing the low-dimensional material on a substrate; preparing and peeling off the porous organic thin film layer on the substrate; sequentially laminating the porous organic film layer and the supporting material layer on the low-dimensional material; and The low-dimensional material attached with the porous organic thin film layer and the supporting material layer is peeled off from the substrate.

3. The method according to claim 1, characterized in that The low-dimensional material is formed by combining the first low-dimensional material and the second low-dimensional material, and the preparation of the low-dimensional material with a support material layer and a porous organic thin film layer comprises: Prepare the first low-dimensional material to be bonded to the support material layer and the porous organic thin film layer; preparing the second low-dimensional material on a substrate; Laminating the first low-dimensional material with the support material layer and the porous organic thin film layer on the second low-dimensional material to form a heterojunction between the first low-dimensional material and the second low-dimensional material; The substrate is peeled off to prepare the low-dimensional material with the support material layer and the porous organic thin film layer.

4. The method according to claim 2, characterized in that The step of preparing the low-dimensional material on a substrate comprises: The low-dimensional material is formed on the substrate by mechanical exfoliation or chemical vapor deposition.

5. The method according to claim 2, characterized in that The step of preparing and peeling off the porous organic thin film layer on the substrate comprises: Coating an organic thin film layer on the substrate, and forming holes in the organic thin film layer by electron beam etching or photolithography to form the organic thin film layer with holes; and The holey organic thin film layer is peeled off from the substrate.

6. The method according to any one of claims 1 to 5, characterized in that: The porous organic film layer is a PMMA film or a polystyrene film, and the thickness of the porous organic film layer is between 100 nanometers and 5 micrometers.

7. The method according to claim 6, characterized in that The support material layer is made of PDMS, and the thickness of the support material layer is between 0.4 mm and 3 mm.

8. The method according to claim 1, characterized in that The low-dimensional material includes one-dimensional material and / or two-dimensional material, the one-dimensional material is carbon nanotube, silicon nanowire or silver nanowire, and the two-dimensional material is graphene, molybdenum disulfide, boron nitride or black phosphorus.

9. The method according to any one of claims 2 to 5, characterized in that: The substrate or the base is made of silicon, silicon oxide or sapphire.

10. A suspended low-dimensional material, characterized in that: The suspended low-dimensional material is made by the method according to any one of claims 1 to 9.

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