Bismuth telluride nanopore maskless direct writing preparation method based on electron beam irradiation

Abstract

The invention discloses a bismuth telluride nanopore maskless direct writing preparation method based on electron beam irradiation, and belongs to the technical field of nanometer manufacturing. The method comprises the following steps: firstly, constructing an initial nanopore in a two-dimensional bismuth telluride material by utilizing a converged electron beam; and then the aperture size of the nanopore is accurately regulated and controlled by adjusting the beam density of the electron beam. The method effectively solves the key technical bottlenecks of interface chemical residue pollution caused by a traditional photoresist mask process, intrinsic defect formation caused by high-energy particle bombardment and the like, and breaks through the limitation of an existing etching technology in the aspect of sub-nanoscale structure precision control; precise control of the aperture of the nanopore can be achieved by adjusting the irradiation intensity of the electron beam, and the method has the advantages of being easy and convenient to operate, low in cost, environmentally friendly and the like and can be widely applied to the fields of nanometer electronic devices, sensors and the like.

Description

Technical Field

[0001] The present invention relates to the field of nanomanufacturing technology, and in particular to a maskless direct writing preparation method for bismuth telluride nanopores based on electron beam irradiation. Background Art

[0002] Bismuth telluride, a member of the topological insulator family, has broad applications in electronics and spintronics. The surface states of topological materials can also couple with light fields to form surface plasmons, making them highly promising for nanophotonics. Constructing precise nanostructures at the nanoscale is crucial for applications such as nanoelectronic devices and sensors. Traditional nanostructure fabrication relies on photoresist masking techniques (such as electron beam lithography and focused ion beam etching), which can reduce critical dimensions to tens of nanometers. However, this technique is prone to introducing chemical residues or ion implantation damage, which can degrade the surface properties of topological insulators. High-energy electron beam irradiation in transmission electron microscopy, a resist-free nanofabrication method, offers the advantages of high precision and flexibility. However, existing techniques for constructing nanopores using electron beam irradiation struggle to simultaneously image and fabricate them due to the high intensity of the focused electron beam, making precise control of the nanopore size difficult. Summary of the Invention

[0003] To achieve precise fabrication of bismuth telluride nanopore structures, this invention provides a maskless direct-write method for preparing bismuth telluride nanopores based on electron beam irradiation. By adjusting the electron beam current density, the nanopore diameter can be precisely controlled. This application effectively addresses key technical bottlenecks such as residual chemical contamination at the interface caused by traditional photoresist masking processes and the formation of intrinsic defects caused by high-energy particle bombardment. It also overcomes the limitations of existing etching technologies in controlling subnanometer structural precision. This method can achieve an aperture processing accuracy of ≤2 nm.

[0004] According to the first aspect of the present invention, the present invention provides a maskless direct writing preparation method of bismuth telluride nanopores based on electron beam irradiation, firstly, an initial nanopore is constructed on a two-dimensional bismuth telluride material using a convergent electron beam in a transmission electron microscope, and then the initial nanopore is irradiated with an electron beam by adjusting the beam current density of the electron beam to control the pore size of the nanopore.

[0005] Preferably, the two-dimensional bismuth telluride material is a multilayer (preferably less than 10 layers, for example, 5-6 layers) bismuth telluride material prepared by the tape-tearing method. The tape-tearing method is a minimalist preparation technique that repeatedly mechanically peels bulk crystals and separates them with adhesive tape to obtain single-layer or few-layer two-dimensional materials.

[0006] Preferably, the construction of the initial nanopore can be performed using a transmission electron microscope (TEM) with an electron acceleration voltage of 200-300 kV.

[0007] Preferably, the electron beam irradiation reduces the beam current density when the nanopore diameter needs to be reduced, and increases the beam current density when the nanopore diameter needs to be increased, compared to the initial nanopore diameter.

[0008] In certain embodiments of the present invention, when it is necessary to reduce the aperture of the nanopore, the beam current density is controlled to be When the nanopore diameter needs to be increased, the beam density is controlled within Irradiation within the range.

[0009] Preferably, the electron beam irradiation time is adjusted according to the desired pore size, and the size change of the nanopores is observed in real time by transmission electron microscopy (TEM) during the irradiation process.

[0010] In certain embodiments of the present invention, the final bismuth telluride nanopore diameter is adjustable between 1 and 10 nm.

[0011] According to a second aspect of the present invention, the present invention provides a bismuth telluride nanopore prepared by the method described in the first aspect.

[0012] According to the third aspect of the present invention, the present invention provides a use of bismuth telluride nanopores prepared by the method described in the first aspect, which is used to prepare high-sensitivity sensing detection and molecular-level separation devices or sensors, and can achieve accurate identification and selective filtration of targets through nanoscale channels.

[0013] Compared with the prior art, the present invention has the following significant advantages: The present invention does not require the use of resist materials in traditional photolithography, avoids complex processes such as resist coating and development, simplifies the preparation process, reduces costs, and avoids the influence of resist residues on the performance of the nanopores.

[0014] By adjusting the electron beam current density, the bismuth telluride nanopore size was precisely controlled: lowering the beam current density resulted in a smaller nanopore diameter, while increasing it increased it, thus achieving bidirectional control of the nanopore size. Furthermore, during the electron beam irradiation process, the nanopore's evolution could be observed in real time using a transmission electron microscope. Based on the observations, irradiation parameters could be adjusted promptly to ensure the desired nanopore size, thus improving the controllability of the fabrication process. The principle behind reducing the nanopore diameter by reducing the beam current density is that the high-energy electron beam activates atomic migration through energy transfer, causing atoms originally sputtered during nanopore construction and atoms surrounding the nanopore to gain energy and migrate. These atoms preferentially migrate to low-energy sites at the nanopore's edge, filling the nanopore. By controlling the beam current density, the atomic filling rate can be made to exceed the sputtering rate, thereby reducing the pore size.

[0015] This method is suitable for regulating bismuth telluride nanopores of different initial sizes, providing a flexible size control method for the preparation of bismuth telluride-based nanodevices, and has broad application prospects in nanoelectronics, sensors and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The electron beam irradiation control technology (beam current density: ) Transmission electron microscopy characterization results of pore size reduction of bismuth telluride nanopores (initial pore size 2.5 nm).

[0017] Figure 2 The electron beam irradiation control technology (beam current density: ) Transmission electron microscopy characterization results of pore size reduction of bismuth telluride nanopores (initial pore size 2.0 nm).

[0018] Figure 3 The electron beam irradiation control technology (beam current density: ) Transmission electron microscopy results of pore size enlargement of bismuth telluride nanopores (initial pore size 2.9 nm).

[0019] Figure 4 The electron beam irradiation control technology (beam current density: ) Transmission electron microscopy results of pore size enlargement of bismuth telluride nanopores (initial pore size 2.1 nm).

[0020] Figure 5 The electron beam irradiation control technology (beam current density: ) Transmission electron microscopy characterization results of pore size enlargement of bismuth telluride nanopores (initial pore size 1.6 nm). DETAILED DESCRIPTION

[0021] The two-dimensional bismuth telluride sample in the examples of the present application is a bismuth telluride single crystal from Nanjing Muke Nanotechnology Co., Ltd.; the transmission electron microscope is a FEI Titan 80-300.

[0022] Example 1:

[0023] The two-dimensional bismuth telluride sample was placed in a transmission electron microscope (TEM) with an electron acceleration voltage of 300 kV. A convergent electron beam was used to construct an initial nanopore with a diameter of about 2.5 nm on the sample.

[0024] Adjust the electron beam current density to , the initial nanopores were irradiated, and the changes of the nanopores were observed in real time by TEM, e.g. Figure 1After 130 s of irradiation, the nanopore diameter was reduced to 2.2 nm.

[0025] Example 2:

[0026] The two-dimensional bismuth telluride sample was placed in a transmission electron microscope (TEM) with an electron acceleration voltage of 300 kV. A convergent electron beam was used to construct an initial nanopore with a diameter of about 2.0 nm on the sample.

[0027] Adjust the electron beam current density to , the initial nanopores were irradiated, and the changes of the nanopores were observed in real time by TEM, e.g. Figure 2 After 57 s of irradiation, the nanopore diameter was reduced to 1.3 nm.

[0028] Example 3:

[0029] The two-dimensional bismuth telluride sample was placed in a transmission electron microscope (TEM) with an electron acceleration voltage of 300 kV. A convergent electron beam was used to construct an initial nanopore with a diameter of about 2.9 nm on the sample.

[0030] Adjust the electron beam current density to , the initial nanopores were irradiated, and the changes of the nanopores were observed in real time by TEM, e.g. Figure 3 After 125 s of irradiation, the nanopore diameter increased to 3.6 nm.

[0031] Example 4:

[0032] The two-dimensional bismuth telluride sample was placed in a transmission electron microscope (TEM) with an electron acceleration voltage of 300 kV. A convergent electron beam was used to construct an initial nanopore with a diameter of about 2.1 nm on the sample.

[0033] Adjust the electron beam current density to , the initial nanopores were irradiated, and the changes of the nanopores were observed in real time by TEM, e.g. Figure 4 After 148 s of irradiation, the nanopore grew to 3.2 nm.

[0034] Example 5:

[0035] The two-dimensional bismuth telluride sample was placed in a transmission electron microscope (TEM) with an electron acceleration voltage of 300 kV. A convergent electron beam was used to construct an initial nanopore with a diameter of about 1.6 nm on the sample.

[0036] Adjust the electron beam current density to , the initial nanopores were irradiated, and the changes of the nanopores were observed in real time by TEM, e.g. Figure 5 After 67 s of irradiation, the nanopore diameter rapidly increased to 3.7 nm.

[0037] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A maskless direct writing method for preparing bismuth telluride nanopores based on electron beam irradiation. First, an initial nanopore is constructed on a two-dimensional bismuth telluride material using a convergent electron beam in a transmission electron microscope. Then, the initial nanopore is irradiated with an electron beam by adjusting the beam current density of the electron beam to control the pore size of the nanopore. The electron beam irradiation is performed by reducing the beam current density when the nanopore diameter needs to be reduced compared to the initial nanopore diameter; and increasing the beam current density when the nanopore diameter needs to be increased. When the nanopore diameter needs to be reduced, the beam density is controlled within When the nanopore diameter needs to be increased, the beam density is controlled within Irradiation within the range; The electron beam irradiation time is adjusted according to the desired pore size, and the size change of the nanopore is observed in real time by transmission electron microscopy during the irradiation process; The construction of the initial nanopore is carried out using a transmission electron microscope, and the electron acceleration voltage is 200-300 kV.

2. The method according to claim 1, wherein the two-dimensional bismuth telluride material is a multilayer bismuth telluride material prepared by a tape tearing method.

3. The method according to claim 1, wherein the initial nanopore is 2.5 nm, and the electron beam current density is adjusted to , irradiating the initial nanopore to reduce the pore size of the nanopore; Or the initial nanopore is 2.0 nm, and the electron beam current density is adjusted to , irradiating the initial nanopore to reduce the pore size of the nanopore; Or the initial nanopore is 2.9 nm, and the electron beam current density is adjusted to , irradiating the initial nanopore to increase the nanopore diameter; Or the initial nanopore is 2.1 nm, and the electron beam current density is adjusted to , irradiating the initial nanopore to increase the nanopore diameter; Or the initial nanopore is 1.6nm, and the electron beam current density is adjusted to , the initial nanopore is irradiated to increase the pore size of the nanopore.

4. A bismuth telluride nanopore prepared by the method according to any one of claims 1 to 3.

5. Use of the bismuth telluride nanopore prepared by the method according to any one of claims 1 to 3 for preparing a high-sensitivity sensing detection and molecular-level separation device or sensor.

6. The use according to claim 5, wherein the high-sensitivity sensing detection and molecular-level separation device or sensor achieves accurate identification and selective filtration of targets through nanoscale pores.

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