A transition metal sulfide nanobelt and preparation method thereof

Abstract

The present invention provides a transition metal sulfide nanobelt and a method for preparing the same. The method comprises the following steps: uniformly coating a prepared substrate with a transition metal source and then inverting the substrate onto another clean substrate wafer. The two substrates form a localized space with a spacing on the order of micrometers, which is then placed in a tube furnace. At high temperatures, the transition metal source in the upper layer evaporates and diffuses to the lower substrate, where it reacts with the introduced sulfur source, resulting in a one-dimensional transition metal sulfide nanobelt on the lower substrate. Compared to other conventional methods, this method has the advantages of a shorter process, simpler process, no catalysts, and strong universality. It can be used to prepare a variety of transition metal dichalcogenide (TMDC) nanobelts, providing a new approach to the preparation of one-dimensional nanomaterials.

Description

Technical Field

[0001] The present invention relates to the technical field of nano material growth, in particular to a new method for quickly and simply preparing one-dimensional transition metal sulfide nanobelts and the one-dimensional transition metal sulfide nanobelts prepared thereby. 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 remains a huge challenge.

[0003] At present, although chemical vapor deposition (CVD) and liquid phase synthesis methods can prepare one-dimensional TMDs nanobelts (such as MoS2 NR) to a certain extent, their universality is poor, and the precise control of their size, shape, crystal phase, orientation and number of layers is still a great challenge. At the same time, some require the addition of metal catalysts (such as Ni, etc.), which greatly affects the final crystal quality. In addition, the use of mask lithography and etching can also achieve the preparation of nanobelts to a certain extent by designing the morphology and size of the crystal, but these processes have fixed resolution limits and are sometimes incompatible with 2D materials, which greatly limits the preparation and application of materials. Therefore, there is an urgent need to develop a new method for preparing TMDs NR with strong universality and controllability. Summary of the Invention

[0004] An embodiment of the present invention provides a method for preparing transition metal sulfide nanoribbons, the method comprising the following steps:

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

[0006] (2) placing the substrate upside down on a clean substrate and placing the substrate and the clean substrate together on a high-temperature resistant plate to form a stacked body, and placing the stacked body in a tube furnace, wherein the stacked body comprises, from top to bottom, a substrate, a substrate, and a high-temperature resistant plate; wherein the first surface of the substrate is disposed opposite to the clean substrate, and a gap is formed between the substrate and the clean substrate, and the height of the gap is 50 nm to 10 μm; 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 transition metal sulfide nanobelts.

[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 a SiO2 substrate, sapphire, fused quartz or mica sheet; the substrate includes a SiO2 substrate, sapphire, fused quartz or mica sheet.

[0012] 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.

[0013] Optionally, the transition metal source includes a liquid source or a solid source;

[0014] Preferably, the liquid source includes sodium molybdate, sodium tungstate, or ammonium molybdate; the solid source includes a transition metal target;

[0015] Preferably, the transition metal target comprises molybdenum oxide, tungsten oxide, or niobium oxide.

[0016] Optionally, the chalcogen element supply source includes sulfur powder, selenium powder, sulfide, and selenide;

[0017] Preferably, the chalcogen element supply source includes hydrogen sulfide, ZnS or ZnSe.

[0018] Optionally, the high temperature resistant plate includes a quartz plate;

[0019] Preferably, the transition metal chalcogenide nanoribbons include MoS2 nanoribbons, MoSe2 nanoribbons, WS2 nanoribbons, WSe2 nanoribbons, or NbS2 nanoribbons.

[0020] 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;

[0021] Preferably, the protective gas also serves as a carrier gas;

[0022] Preferably, the protective gas comprises Ar or N2.

[0023] The present invention also provides a transition metal sulfide nanobelt, which is prepared by any of the methods described above.

[0024] Optionally, the transition metal sulfide nanobelt has a length of more than 50 μm and a width of 10-100 nm.

[0025] The present invention stacks a substrate containing a transition metal source on a clean growth substrate to create a confined space with an extremely narrow gap. By regulating the gap spacing or the concentration of the transition metal source, the abnormal ratio of the chalcogen element / transition metal source concentration in the confined space is adjusted. The reaction is carried out at high temperature to achieve the controllable preparation of TMDs NR. This method not only can effectively prepare high-quality TMDs nanoribbons with adjustable number of layers, width and length, but can also be expanded to other types of TMDs NR. The present invention provides a new universal approach for the preparation of TMDs NR, easily achieving the controllable preparation of different types of TMDs NR.

[0026] The advantages of the present invention are:

[0027] Compared to other CVD methods, the process of this invention is simple and easy to implement. It only requires laminating a substrate containing a transition metal source with a clean substrate to create an extremely narrow confined space. At high temperature, the substrate reacts with a sulfur source to produce TMD nanoribbons.

[0028] 2. This method can not only prepare TMDs NR, but also control the width, length and number of nanobelts by adjusting the gap spacing or the concentration of transition metal source.

[0029] 3. This method does not require the addition of metal catalysts, ensuring high-quality samples;

[0030] 4. As a universal method, various types of TMDs NRs can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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:

[0032] Figure 1 It is a schematic diagram of the process of growing transition metal chalcogenide nanoribbons according to the present invention.

[0033] Figure 2 This is a morphology diagram of the tungsten disulfide nanobelt sample prepared by the present invention.

[0034] Figure 3 This is the AFM of the tungsten disulfide nanobelt sample prepared by the present invention.

[0035] Figure 4 This is a TEM atomic structure diagram of the tungsten disulfide nanobelt sample prepared by the present invention.

[0036] Figure 5 This is a morphology diagram of the molybdenum disulfide nanobelt sample prepared by the present invention.

[0037] Figure 6 This is the AFM of the molybdenum disulfide nanobelt sample prepared by the present invention.

[0038] Figure 7 This is a TEM atomic structure diagram of the molybdenum disulfide nanobelt sample prepared by the present invention. DETAILED DESCRIPTION

[0039] 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.

[0040] Example 1

[0041] In such Figure 1 In the schematic diagram of the device shown, the specific steps for preparing tungsten disulfide nanoribbons are as follows:

[0042] (1) The alumina substrate is pretreated with oxygen plasma to improve the hydrophilicity of the surface. Then, a Na2WO4 solution is evenly spin-coated on the first surface of the alumina substrate by spin coating, and then placed on a heating platform at 60-100°C for dehumidification and drying.

[0043] (2) Sublimed sulfur powder was used as a chalcogen source. A uniformly spin-coated alumina substrate was placed face-down on another clean 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 first surface, spin-coated with Na2WO4, faced the clean substrate. A spacer of known thickness was used to create a 1 μm gap between the substrates.

[0044] (3) After evacuating the tubular furnace until the pressure inside the tubular furnace is less than 0.1 Pa, a protective gas 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 850° C. at 18° C. / min, and then keeping the temperature to grow for 30 minutes.

[0045] (IV) After the growth is completed, turn off the heating power supply, maintain the Ar flow rate unchanged, and cool to room temperature to obtain a clean WS2 NR sample on an alumina substrate. Figure 2 As shown. Among them, Figure 2 This is the morphology of a single-layer WS2 NR sample on an alumina substrate. It can be seen that there are hundreds of microns long on the alumina substrate.

[0046] 50nm wide nanoribbon. Figure 3 This is the AFM of the tungsten disulfide nanobelt sample of Example 1 of the present invention. Figure 4 This is a TEM image of the atomic structure of the tungsten disulfide nanobelt sample of Example 1 of the present invention.

[0047] Example 2

[0048] The specific steps for preparing molybdenum disulfide nanobelts are as follows:

[0049] (1) The alumina substrate is pretreated with oxygen plasma to improve the hydrophilicity of the surface. Then, a Na2MoO4 solution is evenly spin-coated on the first surface of the alumina substrate by spraying, and then placed on a heating platform at 60-100°C for dehumidification and drying.

[0050] (2) Using ZnS as a chalcogen source. A uniformly spin-coated alumina substrate was placed face-down on another clean 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 first surface, sprayed with the Na2MoO4 solution, was positioned opposite the clean substrate. A spacer of known thickness was used to create a gap between the substrates, with the gap height being 800 nm.

[0051] (3) After evacuating the tube furnace until the pressure inside the tube furnace is less than 0.1 Pa, a protective gas is introduced, and the protective gas flows through the chalcogen element supply source and the stacked body in sequence, maintaining the pressure inside the tube at 150 Pa, and controlling the heating rate to increase the temperature to a predetermined temperature of 800° C. at 15° C. / min.

[0052] Then incubate and grow for 25 minutes.

[0053] (IV) After the growth is completed, turn off the heating power supply, maintain the Ar flow rate unchanged, and cool to room temperature to obtain a clean MoS2 NR sample on an alumina substrate. Figure 5 As shown. Among them, Figure 5 This is the morphology of the MoS2 NR sample on the alumina substrate. Nanobelts hundreds of microns long and 80 nm wide can be seen on the alumina substrate. Figure 6 This is the AFM of the molybdenum disulfide nanobelt sample of Example 2 of the present invention.

[0054] Figure 7 This is a TEM image of the atomic structure of the molybdenum disulfide nanobelt sample of Example 2 of the present invention.

[0055] 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, characterized in that: The method comprises the following steps: (1) forming a transition metal source on a first surface of a substrate; (2) Inverting the substrate onto a clean substrate and placing the substrate and the clean substrate together on a high-temperature resistant plate to form a stacked body, and placing the stacked body in a tube furnace, wherein the stacked body comprises, from top to bottom, a substrate, a substrate, and a high-temperature resistant plate; wherein a first surface of the substrate is disposed opposite to the clean substrate, and a gap is formed between the substrate and the clean substrate, and the height of the gap is 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, 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 transition metal sulfide nanobelts.

2. The method according to claim 1, characterized in that Before step (1), 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 a SiO2 substrate, sapphire, fused quartz or a mica sheet; the substrate includes a SiO2 substrate, sapphire, fused quartz or a mica sheet.

4. The method according to claim 1, wherein Step (1) specifically includes 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 platform at 60-100° C. for dehumidification and drying.

5. 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 material includes one or more of molybdenum oxide, tungsten oxide, or niobium oxide.

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

7. The method according to claim 1, characterized in that The chalcogen element supply source includes one or more of hydrogen sulfide, ZnS or ZnSe.

8. The method according to claim 1, characterized in that The high temperature resistant plate includes a quartz plate; The transition metal sulfide nanobelts include one or more of MoS2 nanobelts, MoSe2 nanobelts, WS2 nanobelts, WSe2 nanobelts, or NbS2 nanobelts.

9. The method according to claim 1, characterized in that In step (3), heating under low pressure comprises: 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; The protective gas also serves as a carrier gas; The protective gas includes Ar or N2.

10. A transition metal sulfide nanobelt, characterized in that: The transition metal sulfide nanobelt is prepared by the method according to any one of claims 1 to 9.

11. The transition metal sulfide nanobelt according to claim 10, characterized in that The transition metal sulfide nanobelt has a length of more than 50 μm and a width of 10-100 nm.

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