Preparation method of buffer layer assisted super-flat two-dimensional tellurium ene phase

Abstract

The invention discloses a preparation method of a buffer layer assisted super-flat two-dimensional tellurene phase. The preparation method comprises the following steps: taking a gold (100) single crystal as a substrate; by adjusting the set temperature of the Knudsen diffusion furnace, the deposition amount of tellurium on a room-temperature substrate at the corresponding temperature is researched, so that the relation between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium is determined; the growth condition of the two-dimensional tellurium film under the conditions of specific Knudsen diffusion furnace temperature and different substrate temperatures is researched, so that the optimal substrate temperature is determined; based on the obtained set temperature of the Knudsen diffusion furnace and the temperature of the substrate, tellurium atoms are deposited on the substrate to form a buffer layer; characterizing the material by a scanning tunneling microscope to determine the formation of a buffer layer; depositing tellurium on the buffer layer to form an intermediate phase; and carrying out high-temperature annealing treatment on the intermediate phase to obtain the super-flat two-dimensional tellurium-ene phase. According to the invention, the tellurene phase which has a single atomic layer flat structure, multiple mirror symmetry, large area and high uniformity and has an n-type electronic structure is prepared.

Description

Technical Field

[0001] The present invention belongs to the technical field of two-dimensional material preparation, and in particular relates to a method for preparing a two-dimensional tellurene phase. Background Art

[0002] As the two-dimensional counterpart of bulk tellurium, tellurene has a high 2 / (V s), novel quantum phenomena (such as SdH oscillations, quantum Hall phenomenon, non-traditional Weyl nodes, etc.) and a wide spectral response range (mid-infrared to near-infrared), it is widely used in the fields of micro-nanoelectronic devices, quantum devices and optoelectronic devices. At present, the experimental synthesis methods of tellurene mainly include hydrothermal method, physical vapor transport method, chemical vapor deposition method and molecular beam epitaxy method. However, these methods all have some limitations, which greatly limit the further practical application of tellurene. First, due to the multivalent state of tellurium and the coexistence of metal and non-metallic properties, the single-layer tellurene prepared in the experiment is mostly a three-atomic layer non-flat structure, which is difficult to assemble in subsequent applications such as van der Waals heterojunctions. Secondly, the tellurene prepared so far only has single-fold mirror symmetry, which limits its possibility in topological quantum phenomena. In addition, the realization of large-area, highly crystalline single-layer tellurene is still difficult. Finally, the difficulty of experimentally synthesizing undoped intrinsic n-type tellurene has kept related CMOS implementations at the theoretical stage, hindering its large-scale application in integrated circuits. To address the shortcomings of existing experimental synthesis techniques, the present invention provides a buffer-layer-assisted synthesis method to prepare a novel two-dimensional tellurene phase. This novel tellurene phase addresses the shortcomings of existing tellurene and is expected to promote the development of related digital electronics technologies. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing an ultra-flat two-dimensional tellurene phase assisted by a buffer layer, so as to prepare a tellurene phase having a single atomic layer flat structure, multiple mirror symmetry, high uniformity over a large area and an n-type electronic structure.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase comprises the following steps:

[0006] (1) Using a gold (100) single crystal as a substrate and treating it to make its surface clean;

[0007] (2) By adjusting the set temperature of the Knudsen diffusion furnace, the deposition amount of tellurium on the gold (100) single crystal at room temperature at the corresponding temperature was studied, thereby determining the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium;

[0008] (3) repeating step (1) to remove the tellurium atoms deposited in step (2) from the surface of the gold (100) single crystal;

[0009] (4) Based on the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium obtained in step (2), the growth of two-dimensional tellurium thin films under the conditions of a specific Knudsen diffusion furnace temperature and different substrate temperatures is studied to determine the optimal substrate temperature;

[0010] (5) repeating step (1) to remove the tellurium atoms deposited in step (4) from the surface of the gold (100) single crystal;

[0011] (6) depositing tellurium atoms on the substrate to form a buffer layer based on the set temperature of the Knudsen diffusion furnace and the substrate temperature obtained in steps (2) and (4);

[0012] (7) Characterizing the material by scanning tunneling microscopy to determine the formation of the buffer layer;

[0013] (8) Depositing tellurium on the buffer layer to form an intermediate phase;

[0014] (9) The intermediate phase is subjected to high-temperature annealing treatment to obtain an ultra-flat two-dimensional tellurene phase.

[0015] Preferably, in step (1), the step of treating the substrate is: -5 The gold (100) single crystal was sputtered for 15 min in an argon atmosphere, and then heated at 400 ° C for 15 min to evaporate the surface impurity layer and form a 10 4 nm 2 After repeating the sputtering-heating process 4-5 times, the surface morphology is characterized by scanning tunneling microscopy. If there are no obvious clusters on the surface, the surface is clean.

[0016] Preferably, in step (2), the set temperature of the Knudsen diffusion furnace is adjusted in steps of 10°C within the temperature range of 270°C to 330°C, and the deposition amount of tellurium on the room temperature gold (100) single crystal at the corresponding temperature is studied.

[0017] Preferably, in step (4), the growth of two-dimensional tellurium thin films is studied when the substrate temperature is 300°C, 350°C, and 400°C in a Knudsen diffusion furnace at 310°C.

[0018] Preferably, in step (6), the substrate is heated to 400° C., and the Knudsen diffusion furnace is heated to 310° C. so that tellurium is incident on the gold (100) substrate in the form of a directional molecular beam to grow the buffer layer, and the growth time is controlled within 15 minutes.

[0019] Preferably, in step (7), after the growth is completed, the substrate temperature is allowed to drop to room temperature, and the sample is transferred into a scanning tunneling microscope for structural characterization at 4K.

[0020] Preferably, in step (8), tellurium is deposited at a substrate temperature of 400° C. and a Knudsen diffusion furnace temperature of 310° C., and the deposition time is controlled within 15 minutes.

[0021] Preferably, in step (9), based on step (8), the sample is subjected to post-annealing treatment at a substrate temperature of 400° C., and the duration is controlled within 45 minutes.

[0022] Beneficial Effects: This invention proposes for the first time a method for growing an ultra-flat two-dimensional tellurene phase using a homogeneous buffer layer. Compared with the existing technology, it has the following advantages:

[0023] (1) The growth substrate is metal rather than the commonly used graphene-based silicon carbide, so the prepared tellurene phase is no longer limited to the common β phase;

[0024] (2) The introduction of a homogeneous buffer layer weakens the coupling between the metal substrate and the two-dimensional tellurene, and there is no covalent bond between the homogeneous buffer layer and the two-dimensional tellurene, so that the intrinsic properties of the two-dimensional tellurene are not affected;

[0025] (3) The two-dimensional tellurene phase prepared in the present invention has a single atomic layer ultra-flat structure, two-fold mirror symmetry and an n-type electronic band structure of 1.55 eV;

[0026] (4) The two-dimensional tellurene phase prepared in the present invention can achieve uniform and full coverage on the surface of the gold (100) single crystal, realizing for the first time the growth of atomically flat monolayer tellurene at the centimeter scale, and customized growth can be achieved by changing the shape and size of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The gold (100) substrate selected in the present invention is processed into a hat shape, 1 is the surface for tellurium deposition and growth, and 2 is an annular platform that plays a fixing role;

[0028] Figure 2 This is a scanning tunneling microscope image of the clean gold (100) substrate obtained by processing in steps (1), (3), and (5) in the embodiment;

[0029] Figure 3 Schematic diagram of the process for preparing an ultra-flat two-dimensional tellurene phase in the present invention; wherein 3 is a buffer layer, 4 is a gold (100) substrate, 5 is an intermediate phase, and 6 is an ultra-flat two-dimensional tellurene phase;

[0030] Figure 4Schematic diagram of the atomic structure of the buffer layer; 7 is a top view and 8 is a side view;

[0031] Figure 5 Schematic diagram of the atomic structure of the ultra-flat two-dimensional tellurene phase; 9 is a top view and 10 is a side view;

[0032] Figure 6 A large-scale scanning tunneling microscope image (50 nm × 50 nm) of the mesophase prepared in step (8) of the embodiment;

[0033] Figure 7 1 is an atomic scale scanning tunneling microscope image of the mesophase prepared in step (8) of the embodiment; wherein 11 is the mesophase, and 12 is the buffer layer below the mesophase;

[0034] Figure 8 A large-scale scanning tunneling microscopy image (100 nm × 100 nm) of the ultra-flat two-dimensional tellurene phase prepared in step (9) of the embodiment;

[0035] Figure 9 This is an atomic scale scanning tunneling microscope image of the ultra-flat two-dimensional tellurene phase prepared in step (9) of the embodiment;

[0036] Figure 10 This is the scanning tunneling spectrum of the ultra-flat two-dimensional tellurene phase; it can be seen from the spectrum that the ultra-flat two-dimensional tellurene phase has an n-type electronic band structure of 1.55eV. DETAILED DESCRIPTION

[0037] The present invention will be further explained below with reference to the accompanying drawings.

[0038] The present invention provides a method for preparing an ultra-flat two-dimensional tellurene phase assisted by a buffer layer, comprising the following steps:

[0039] (1) Using gold (100) single crystal as substrate and treating it to make its surface clean; Figure 1 As shown, in some embodiments, the substrate is processed into a hat shape, having a surface 1 for tellurium deposition and growth and an annular platform 2 for fixing.

[0040] In some embodiments, the steps of processing the substrate are: sputtering the gold (100) single crystal in an argon atmosphere, then heating the gold (100) single crystal to evaporate the impurity layer on its surface and form steps, repeating the sputtering-heating process several times, and then characterizing its surface morphology using a scanning tunneling microscope. If there are no obvious clusters on the surface, the surface is clean.

[0041] (2) By adjusting the set temperature of the Knudsen diffusion furnace, the deposition amount of tellurium on the gold (100) single crystal at room temperature at the corresponding temperature is studied, thereby determining the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium.

[0042] (3) Repeat step (1) to remove the tellurium atoms deposited in step (2) from the surface of the gold (100) single crystal.

[0043] (4) Based on the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium obtained in step (2), the growth of two-dimensional tellurium thin films under specific Knudsen diffusion furnace temperatures and different substrate temperatures is studied to determine the optimal substrate temperature.

[0044] (5) Repeat step (1) to remove the tellurium atoms deposited in step (4) from the surface of the gold (100) single crystal.

[0045] (6) Based on the set temperature of the Knudsen diffusion furnace and the substrate temperature obtained in steps (2) and (4), tellurium atoms are deposited on the substrate to form a buffer layer.

[0046] (7) The formation of the buffer layer was confirmed by characterizing the material using scanning tunneling microscopy.

[0047] (8) Tellurium is deposited on the buffer layer to form an intermediate phase.

[0048] (9) The intermediate phase is subjected to high-temperature annealing treatment to obtain an ultra-flat two-dimensional tellurene phase.

[0049] The present invention will be further described below in conjunction with the examples. The present invention can be better understood according to the following examples. However, it is readily understood by those skilled in the art that the specific material proportions, process conditions and results described in the examples are only intended to illustrate the present invention.

[0050] Example

[0051] In this example, the following reagents and instruments were used:

[0052] Gold (100) single crystal: MaTeck

[0053] Tellurium powder: 99.999%, aladdin

[0054] Scanning tunneling microscope: LT-STM, Scienta Omicron

[0055] High vacuum molecular beam epitaxy system: RM-type, Scienta Omicron

[0056] Knudsen diffusion furnace: E38LT / MT, FERMI

[0057] The method for preparing the buffer layer-assisted ultra-flat two-dimensional tellurene phase of this embodiment includes the following steps:

[0058] (1) Take gold (100) single crystal as substrate, process it and determine the cleanliness of the substrate. Figure 1 As shown, the substrate is processed into a hat shape, having a surface 1 for tellurium deposition and growth and an annular platform 2 for fixing.

[0059] The steps of treating the substrate are as follows: -5 The gold (100) single crystal was sputtered for 15 min in an argon atmosphere, and then heated at 400 ° C for 15 min to evaporate the surface impurity layer and form a 10 4 nm 2 After repeating the sputtering-heating process 4-5 times, the surface morphology is characterized by scanning tunneling microscopy. If there are no obvious clusters on the surface, the surface is clean. Figure 2 shown.

[0060] (2) By adjusting the set temperature of the Knudsen diffusion furnace in steps of 10°C within the temperature range of 270°C to 330°C, the deposition amount of tellurium on a gold (100) single crystal at room temperature at the corresponding temperature was studied, thereby determining the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium.

[0061] (3) Repeat step (1) to remove the tellurium atoms deposited on the surface in step (2) from the surface of the gold (100) single crystal.

[0062] (4) Based on the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium obtained in step (2), the growth of two-dimensional tellurium thin films is studied when the Knudsen diffusion furnace is at 310°C and the substrate temperatures are 300°C, 350°C, and 400°C, so as to determine the optimal substrate temperature.

[0063] (5) Repeat step (1) to remove the tellurium atoms deposited on the surface in step (4) from the surface of the gold (100) single crystal.

[0064] (6) Based on the research experience of steps (2) and (4), the substrate was heated to 400°C, and the Knudsen diffusion furnace was heated to 310°C to allow tellurium to be incident on the gold (100) substrate in the form of a directional molecular beam to grow the buffer layer. The growth time was controlled to 15 minutes.

[0065] (7) After the buffer layer growth is completed, wait for the substrate temperature to drop to room temperature, transfer the sample into a scanning tunneling microscope, and perform structural characterization at 4K.

[0066] (8) Based on step (7), tellurium was deposited at a substrate temperature of 400°C and a Knudsen diffusion furnace of 310°C to form an intermediate phase. The deposition time was controlled within 15 minutes. The scanning tunneling microscope image of the intermediate phase prepared in this step is shown in FIG. Figure 6 and Figure 7 shown.

[0067] (9) Based on step (8), the intermediate phase is subjected to post-annealing treatment at a substrate temperature of 400°C for 45 minutes to obtain an ultra-flat two-dimensional tellurene phase. The scanning tunneling microscope image of the ultra-flat two-dimensional tellurene phase prepared in this step is as follows: Figure 8 and Figure 9 The scanning tunneling spectrum of the ultra-flat two-dimensional tellurene phase is shown in Figure 10 As shown, it can be seen from the spectrum that the ultra-flat two-dimensional tellurene phase has an n-type electronic band structure of 1.55eV.

[0068] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an ultra-flat two-dimensional tellurene phase assisted by a buffer layer, characterized in that: The following steps are involved: (1) Using a gold (100) single crystal as a substrate and treating it to make its surface clean; (2) By adjusting the set temperature of the Knudsen diffusion furnace, the deposition amount of tellurium on the gold (100) single crystal at room temperature at the corresponding temperature was studied, thereby determining the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium; (3) repeating step (1) to remove the tellurium atoms deposited in step (2) from the surface of the gold (100) single crystal; (4) Based on the relationship between the set temperature of the Knudsen diffusion furnace and the evaporation amount of tellurium obtained in step (2), the growth of two-dimensional tellurium thin films under the conditions of a specific Knudsen diffusion furnace temperature and different substrate temperatures is studied to determine the optimal substrate temperature; (5) repeating step (1) to remove the tellurium atoms deposited in step (4) from the surface of the gold (100) single crystal; (6) depositing tellurium atoms on the substrate to form a buffer layer based on the set temperature of the Knudsen diffusion furnace and the substrate temperature obtained in steps (2) and (4); (7) Characterizing the material by scanning tunneling microscopy to determine the formation of the buffer layer; (8) Depositing tellurium on the buffer layer to form an intermediate phase; (9) The intermediate phase is subjected to high-temperature annealing treatment to obtain an ultra-flat two-dimensional tellurene phase.

2. The method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase according to claim 1, characterized in that: In step (1), at 2×10 -5 The gold (100) single crystal was sputtered for 15 min in an argon atmosphere, and then heated at 400 ° C for 15 min to evaporate the surface impurity layer and form a 10 4 nm 2 After repeating the sputtering-heating process 4-5 times, the surface morphology was characterized by scanning tunneling microscopy. If there were no obvious clusters on the surface, the surface was clean.

3. The method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase according to claim 1, characterized in that: In step (2), the set temperature of the Knudsen diffusion furnace is adjusted in steps of 10°C within the temperature range of 270°C to 330°C, and the deposition amount of tellurium on the room temperature gold (100) single crystal at the corresponding temperature is studied.

4. The method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase according to claim 1, characterized in that: In step (4), the growth of two-dimensional tellurium thin films is studied when the substrate temperature is 300°C, 350°C, and 400°C in a Knudsen diffusion furnace at 310°C.

5. The method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase according to claim 1, characterized in that: In step (6), the substrate is heated to 400° C., and the Knudsen diffusion furnace is heated to 310° C. so that tellurium is incident on the gold (100) substrate in the form of a directional molecular beam to grow the buffer layer. The growth time is controlled within 15 minutes.

6. The method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase according to claim 1, characterized in that: In step (7), after the growth is completed, wait for the substrate temperature to drop to room temperature, transfer the sample into a scanning tunneling microscope, and perform structural characterization at 4K.

7. The method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase according to claim 1, characterized in that: In step (8), tellurium is deposited at a substrate temperature of 400° C. and a Knudsen diffusion furnace temperature of 310° C., and the deposition time is controlled within 15 minutes.

8. The method for preparing a buffer layer-assisted ultra-flat two-dimensional tellurene phase according to claim 1, characterized in that: In step (9), based on step (8), the sample is subjected to post-annealing treatment at a substrate temperature of 400° C., and the duration is controlled within 45 minutes.

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