A transition metal sulfide nanoribbon with high orientation, tunable edge structure and chirality

Abstract

The present invention provides a transition metal sulfide nanobelt with high orientation, adjustable edge structure and chirality, and a preparation method thereof. The preparation method comprises the following steps: annealing a growth substrate at high temperature to form a step distribution on the substrate surface. A prepared substrate is evenly coated with a layer of transition metal source and then flipped over onto a pretreated growth substrate. Through surface interface regulation and utilizing the atomic-level steps of the growth substrate, a one-dimensional transition metal sulfide nanobelt with consistent orientation, adjustable edge structure and chirality is obtained on the growth substrate. This method has the characteristics of a short process, simple process, no catalyst, strong controllability and universality. It can not only regulate the dimension of the grown material and realize the controllable preparation of one-dimensional transition metal sulfide nanobelts, but more importantly, it can effectively control the growth orientation, edge structure and chirality of the one-dimensional nanomaterial, which is of great significance for studying the electronic structure of nanomaterials.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterial growth, and in particular to a new method for preparing one-dimensional nanobelts with controllable orientation, edge structure and chirality, and the prepared transition metal sulfide nanobelts with high orientation, edge structure and adjustable chirality. Background Art

[0002] When the width of two-dimensional (2D) crystalline materials is reduced to quasi-one-dimensional nanostructures, commonly known as nanoribbons (NRs), the electronic structure of the material can be manipulated. For example, graphene NRs with controllable edge structure, chirality, and superlattices can open the graphene band gap, generating metallic properties, topological quantum phases, and Coulomb blockade (CB). Two-dimensional transition metal dichalcogenide (TMD) crystals are a versatile platform for studying optoelectronics, catalysis, and quantum devices. For a long time, research on TMDs has primarily focused on the two-dimensional planar dimension, using phase transition engineering, stress engineering, and alloying and doping to manipulate their electronic structure and, in turn, their physical properties. However, the dimensionality and Wiener structure of TMDs also play a crucial role in their intrinsic physical properties. For example, the structure, density, and strain state of active sites at the edges and planes of TMDs determine their catalytic selectivity and activity. In quantum optoelectronic devices, the shape and length of the patterned TMD channel material significantly influence the operability of carriers and excitons. Although many ideal material properties are determined by the micro / nanostructure and size of crystalline materials, there is a lack of synthetic methods for precisely manipulating these structural properties. For example, the preparation of one-dimensional nanomaterials with consistent orientation, tunable edge structure and chirality still faces great challenges.

[0003] Although chemical vapor deposition (CVD) and liquid-phase synthesis methods can be used to prepare some TMD nanoribbons, precise control of their length, width, crystal phase, orientation, and number of layers remains a major challenge. In addition, photolithography and etching methods can also achieve the design of crystal morphology and size to a certain extent, but these processes have fixed resolution limits and are sometimes incompatible with 2D materials, greatly limiting the preparation and application of materials. Therefore, how to achieve the control of the dimensionality, edge state structure, and chirality of two-dimensional crystalline materials and effectively prepare high-quality, highly oriented one-dimensional TMD nanoribbons with adjustable structure and properties has become a key issue that needs to be solved urgently. Summary of the Invention

[0004] An embodiment of the present invention provides a method for preparing transition metal sulfide nanoribbons with high orientation, edge structure, and adjustable chirality, the method comprising the following steps:

[0005] (1) forming a transition metal source on a first surface of a substrate;

[0006] (2) annealing the substrate to serve as a growth substrate; placing the substrate from step (1) upside down on the annealed growth substrate and placing the two together on a high-temperature resistant plate to form a stack, and placing the stack in a tube furnace, wherein the stack comprises, from top to bottom, a substrate, a growth substrate, and a high-temperature resistant plate; wherein a first surface of the substrate is disposed opposite to the growth substrate, with a gap formed between the substrate and the growth substrate; and placing a chalcogen element supply source in the tube furnace;

[0007] (3) introducing a protective gas at normal pressure or low pressure and raising the temperature, wherein the protective gas flows sequentially through the chalcogen element supply source and the stack, raising the temperature to a predetermined temperature at a controlled rate of 5-100° C. / min, and then maintaining the temperature for a growth period of 40 minutes or less; wherein the predetermined temperature range is 500-1000° C.;

[0008] (4) After the growth is completed, the heating power supply is turned off, the flow rate of the protective gas is maintained unchanged, and the mixture is cooled to room temperature to obtain a highly oriented transition metal sulfide nanobelt with adjustable chirality on the growth substrate.

[0009] Optionally, before step 1, the method further includes the following steps: pre-treating the substrate, wherein the pre-treatment includes plasma treatment, KOH solution treatment or piranha solution treatment;

[0010] Preferably, the pretreatment comprises oxygen plasma treatment.

[0011] Optionally, the base includes one or more of SiO2 substrate, sapphire, fused quartz or mica sheet; the substrate includes one or more of alumina, gold foil, ST-cut quartz or Ga2O3;

[0012] Preferably, annealing the substrate includes: performing a high-temperature annealing treatment on the substrate at 800-1600° C. to achieve recrystallization of the substrate surface to form a step-shaped distribution structure.

[0013] Optionally, step one specifically includes the following steps: uniformly spin-coating the transition metal source on the prepared substrate by a spin coating method or a spray coating method, and then placing it on a heating platform at 60-100° C. for dehumidification and drying.

[0014] Optionally, the transition metal source includes a liquid source or a solid source;

[0015] Preferably, the liquid source comprises one or more of sodium molybdate, sodium tungstate, or ammonium molybdate; the solid source comprises a transition metal target;

[0016] Preferably, the transition metal target comprises one or more of molybdenum oxide, tungsten oxide, or niobium oxide.

[0017] Optionally, the chalcogen element supply source includes one or more of sulfur powder, selenium powder, sulfide, and selenide;

[0018] Preferably, the chalcogen element supply source includes one or more of hydrogen sulfide, ZnS or ZnSe.

[0019] Optionally, the gap height is 50 nm-10 μm;

[0020] Preferably, the high temperature resistant plate comprises a quartz plate;

[0021] Preferably, the transition metal chalcogenide nanoribbons include WS2 nanoribbons, MoS2 nanoribbons, MoSe2 nanoribbons, WSe2 nanoribbons, or NbS2 nanoribbons.

[0022] Optionally, heating under low pressure in step 3 includes: evacuating the tube furnace until the pressure inside the tube furnace is lower than 0.1 Pa, introducing a protective gas, maintaining the pressure inside the tube at 50-300 Pa, and heating to a predetermined temperature;

[0023] Preferably, the protective gas also serves as a carrier gas;

[0024] Preferably, the protective gas comprises Ar or N2.

[0025] The present invention also provides a transition metal sulfide nanobelt with high orientation, edge structure and adjustable chirality. The transition metal sulfide nanobelt is prepared by any of the methods described above.

[0026] Optionally, the transition metal sulfide nanobelt prepared on an a-plane growth substrate has a zigzag edge structure, and the transition metal sulfide nanobelt prepared on a c-plane growth substrate has an armchair edge structure.

[0027] The present invention achieves the controllable preparation of one-dimensional TMD nanoribbons with high orientation, adjustable edge structure, and chirality through surface interface regulation, utilizing the interaction of the step structure formed on the surface of the substrate after high-temperature annealing treatment with the one-dimensional nanoribbon. This method not only effectively controls the number of layers, width, and length of the TMD nanoribbons, but also, most importantly, the orientation, edge structure, and chirality of the nanoribbons, resulting in high-quality TMD nanoribbons with consistent growth orientation, defined edges, and chirality. This provides a new approach for the controllable preparation of one-dimensional TMD nanoribbons and is of great significance for studying the effects of edge states, chirality, and dimensionality on the electronic structure of low-dimensional materials.

[0028] The advantages of the present invention are:

[0029] 1. Compared with other CVD or liquid-phase synthesis methods, the process of the present invention is simple and easy. It only requires high-temperature annealing of the growth substrate. By controlling the surface interface and utilizing the surface step structure, the preparation of TMDs nanoribbons with consistent orientation, controllable edge structure and chirality is achieved.

[0030] 2. This method can not only prepare TMDs NR, but also regulate the width, growth orientation, edge structure and chirality of nanoribbons by controlling annealing conditions and selecting different substrate crystal plane orientations.

[0031] 3. This method does not require the addition of metal catalysts, ensuring high-quality samples;

[0032] 4. As a general method, other types of TMDs NRs can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0034] Figure 1 This is a schematic diagram of the process of growing highly oriented, chirally adjustable WS2 nanoribbons according to the present invention.

[0035] Figure 2 This is the AFM image of the step-like structure distribution on the surface of the alumina substrate before and after high-temperature annealing.

[0036] Figure 3 It is a schematic diagram of the atomic structure of tungsten disulfide nanoribbons with high orientation and zigzag edge structure prepared on an a-plane alumina substrate in Example 1 of the present invention.

[0037] Figure 4 These are the optical image, high-resolution AFM, and atomic phase of the highly oriented, zigzag edge structured tungsten disulfide nanoribbon sample of Example 1 of the present invention.

[0038] Figure 5 This is a schematic diagram of the atomic structure of a tungsten disulfide nanoribbon sample with a high orientation and an armchair edge structure prepared on a c-plane alumina substrate in Example 2 of the present invention.

[0039] Figure 6 These are the optical images, high-resolution AFM, and atomic phases of the highly oriented, armchair-edge-structured tungsten disulfide nanoribbon sample of Example 2 of the present invention. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings 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 those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] Example 1

[0042] In such Figure 1 In the growth diagram shown, the specific steps for preparing highly oriented, zigzag edge structured tungsten disulfide nanoribbons are as follows:

[0043] (1) Using a-plane alumina as the growth substrate, keeping it at 1100℃ for 1h, we can get an alumina substrate with a step distribution on the surface (such as Figure 2 shown).

[0044] (2) Pre-treating the silicon dioxide substrate with oxygen plasma to improve the surface hydrophilicity. Then, evenly coating the first surface of the silicon dioxide substrate with a Na2WO4 solution by spin coating, and then placing the substrate on a heating platform at 60-100°C for dehumidification and drying.

[0045] (3) Zinc sulfide was used as a chalcogen source. A uniformly spin-coated silica substrate was inverted onto an annealed alumina substrate. The two substrates were placed together on a quartz plate to form a stack, which was then placed in a tube furnace. The Na2WO4-spin-coated silica surface was positioned opposite the alumina substrate. A spacer of known thickness was used to separate the substrates, creating a gap of 800 nm.

[0046] (4) After evacuating the tubular furnace until the pressure inside the tubular furnace is lower than 0.1 Pa, a protective gas Ar is introduced, and the protective gas flows through the chalcogen element supply source and the stack in sequence, maintaining the pressure inside the tube at 120 Pa, and controlling the heating rate to increase the temperature to a predetermined temperature of 930° C. at 18° C. / min, and then keeping the temperature to grow for 40 minutes.

[0047] (5) After the growth is completed, the heating power is turned off, the Ar flow rate is maintained unchanged, and the sample is cooled to room temperature to obtain a WS2 nanoribbon sample with uniform orientation and zigzag structure on the a-plane alumina substrate, as shown in FIG. Figure 3 The figure shows the atomic structure of the WS2 nanoribbon sample with consistent orientation and zigzag structure on the a-plane alumina substrate. It can be seen that the zigzag structure is formed along the a-plane alumina substrate. <1100> WS2 nanoribbons with consistent growth orientation in the step direction. Figure 4(a) is an optical image of a WS2 nanoribbon sample with consistent orientation and zigzag edge structure obtained on an a-plane alumina substrate. Figure 4 (b) is the high-resolution AFM and atomic phase image of WS2 nanobelts. It can be clearly seen from the figure that WS2 nanobelts grow along the step direction and have a zigzag edge structure.

[0048] Example 2

[0049] In such Figure 1 In the growth diagram shown, the specific steps for preparing highly oriented, armchair edge-structured tungsten disulfide nanoribbons are as follows:

[0050] (1) Using the alumina crystal surface of the c-plane as the growth substrate, the alumina substrate with a step distribution on the surface was obtained by heating at 1200℃ for 1.5h. Figure 2 shown).

[0051] (2) Pre-treating another alumina substrate with oxygen plasma to improve the hydrophilicity of the surface.

[0052] Then, the Na2WO4 solution is evenly spin-coated on the first surface of the alumina substrate by a spin coating method, and then placed on a 60-100° C. heating table for dehumidification and drying.

[0053] (3) Sublimed sulfur powder was used as a chalcogen source. A uniformly spin-coated alumina substrate was placed on top of an annealed alumina substrate. The two substrates were stacked together on a quartz plate and placed in a tube furnace. The Na2WO4-spin-coated alumina surface was positioned opposite the annealed alumina substrate. A spacer of known thickness was used to separate the two substrates, creating a gap of 1 μm.

[0054] (4) After evacuating the tube furnace until the pressure inside the tube furnace is less than 0.1 Pa, a protective gas Ar is introduced, and the protective gas flows through the chalcogen element supply source and the stack in sequence, maintaining the pressure inside the tube at 120 Pa, and controlling the heating rate to increase the temperature to a predetermined temperature of 950° C. at 15° C. / min.

[0055] Then the cells were incubated and grown for 40 min.

[0056] (5) After the growth is completed, the heating power is turned off, the Ar flow rate is maintained unchanged, and the sample is cooled to room temperature to obtain a WS2 nanoribbon sample with uniform orientation and an armchair structure on the c-plane alumina substrate, as shown in FIG. Figure 5The diagram shows the atomic structure of a WS2 nanoribbon sample with consistent orientation and armchair structure on the c-plane alumina substrate. It can be seen that the WS2 nanoribbon sample is aligned with the c-plane alumina substrate. <1120> WS2 nanoribbons with consistent step direction and growth orientation. Figure 6 (a) The figure shows an optical image of a WS2 nanoribbon sample with consistent orientation and an armchair structure on a c-plane alumina substrate. Figure 6 (b) is the high-resolution AFM and atomic phase image of WS2 nanobelts. It can be clearly seen from the figure that WS2 nanobelts grow along the step direction and have an armchair edge structure.

[0057] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A method for preparing transition metal sulfide nanobelts with high orientation, edge structure and adjustable chirality, characterized in that: The method comprises the following steps: (1) forming a transition metal source on the first surface of the substrate; step 1 specifically comprises the following steps: using a spin coating method or a spray coating method to evenly spin-coat the transition metal source on the prepared substrate, and then placing it on a heating table at 60-100°C for dehumidification and drying; (2) annealing the substrate to serve as a growth substrate; placing the substrate from step (1) upside down on the annealed growth substrate and placing the two together on a high-temperature resistant plate to form a stack, and placing the stack in a tube furnace, wherein the stack comprises, from top to bottom, a substrate, a growth substrate, and a high-temperature resistant plate; wherein the first surface of the substrate is disposed opposite to the growth substrate, and a gap is formed between the substrate and the growth substrate, and the height of the gap is in the range of 50 nm to 10 μm; and placing a chalcogen element supply source in the tube furnace; (3) introducing a protective gas at normal pressure or low pressure and raising the temperature, wherein the protective gas flows sequentially through the chalcogen element supply source and the stack, raising the temperature to a predetermined temperature at a controlled rate of 5-100°C / min, and then maintaining the temperature for a growth period of not more than 40 minutes; wherein the predetermined temperature range is 500-1000°C; (4) after the growth is completed, turning off the heating power supply, maintaining the flow rate of the protective gas unchanged, and cooling to room temperature to obtain a highly oriented transition metal sulfide nanoribbon with adjustable chirality on the growth substrate; The annealing treatment of the substrate includes: performing a high temperature annealing treatment on the substrate at 800-1600° C. to achieve recrystallization of the substrate surface to form a step-shaped distribution structure; The transition metal sulfide nanobelt prepared on an a-plane growth substrate has a zigzag edge structure, and the transition metal sulfide nanobelt prepared on a c-plane growth substrate has an armchair edge structure.

2. The method according to claim 1, characterized in that Before step one, the method further includes the following step: pre-treating the substrate, wherein the pre-treatment includes plasma treatment, KOH solution treatment or piranha solution treatment.

3. The method according to claim 1, characterized in that The base includes one or more of a SiO2 substrate, sapphire, fused quartz or mica sheet; the substrate includes one or more of alumina, gold foil, ST-cut quartz or Ga2O3.

4. The method according to claim 1, wherein The transition metal source includes a liquid source or a solid source; The liquid source includes one or more of sodium molybdate, sodium tungstate, or ammonium molybdate; the solid source includes a transition metal target; The transition metal target includes one or more of molybdenum oxide, tungsten oxide, or niobium oxide.

5. The method according to claim 1, wherein The chalcogen element supply source includes one or more of sulfur powder, selenium powder, sulfide, and selenide.

6. The method according to claim 5, characterized in that The chalcogen element supply source includes one or more of hydrogen sulfide, ZnS or ZnSe.

7. The method according to claim 1, characterized in that The high temperature resistant plate includes a quartz plate; The transition metal chalcogenide nanoribbons include WS2 nanoribbons, MoS2 nanoribbons, MoSe2 nanoribbons, WSe2 nanoribbons, or NbS2 nanoribbons.

8. The method according to claim 1, characterized in that The protective gas also serves as a carrier gas; The protective gas includes Ar or N2.

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