Transient voltage detection method based on array-type quantum spin Hall effect insulator materials

Abstract

The present invention relates to a transient voltage detection method based on an array-type quantum spin Hall effect insulator material. The present invention belongs to the field of new electronic materials and provides a transient voltage detection method, which can realize the measurement of transient voltage within the accuracy of electronic response time. The main scheme includes: step 1: using the first principle calculation to determine the quantum spin Hall effect insulator material with different band gaps, and selecting the ordinary layered insulator material with lattice matching, calculating the band structure and analyzing the behavior of electrons and holes near its Fermi level; step 2: through the interlayer van der Waals effect, the calculated quantum spin Hall effect insulator material with different band gaps is lattice matched with the ordinary insulator material, and built into a multilayer material unit stacked in sequence, and the phonon dispersion of the multilayer material unit is calculated to detect its dynamic stability; step 3: the stable multilayer material unit is combined into an array sensor, prepared by chemical vapor deposition, and the performance parameters of the sensor array are tested.

Description

Technical Field

[0001] The invention belongs to the field of novel electronic materials, and in particular relates to a transient voltage detection method based on array-type quantum spin Hall effect insulator materials. Background Art

[0002] Layered van der Waals new materials are considered to be one of the candidate materials for the next generation of semiconductors due to their excellent physical properties and polycrystalline layered structures. With the rapid development of low-dimensional nanomaterials, nanoscale quantum electronics and other fields, integrating layered van der Waals new materials into existing silicon electronic technology has become a research trend. Through a series of basic studies on nanomaterials with different band structures, many novel properties have been discovered in low-dimensional materials. Among them, the van der Waals nano-insulating materials with quantum spin Hall effect have topologically protected edge states, and special edge states are generated on the surface, making the edge of the insulator conductive. The direction of this edge state current is completely locked with the spin direction of the electron. If the electrons inside this type of material can be manipulated, their energy dissipation can be reduced to a very low level.

[0003] Applying an electric field is a common method for regulating materials, which is also applicable to some insulator materials with quantum spin Hall effect. Based on van der Waals nanomaterials with quantum spin Hall effect, the material should also have properties: the band orbits near the Fermi level are easy to distinguish, such as using the energy levels of different elements to be distributed on different sides of the Fermi level (conduction band and valence band), so that the material can be easily controlled by the electric field. The basic principle is: in the topological state, the edge state of the quantum spin Hall effect insulator material can achieve the "on" state; when an electric field perpendicular to the plane of the nanomaterial is applied, the inversion symmetry of the material can be destroyed, and the Rashba splitting can be introduced near the Fermi level. With the change of the electric field size, the energy gap of the material can be closed and turned on, causing the topological phase transition of the material, resulting in the destruction of the edge state of the material, and the quantum spin Hall effect insulator material at this time becomes an ordinary insulator material. In addition, the electric field size of quantum spin Hall effect insulators with different energy gaps to achieve "on" and "off" is different. On this basis, by integrating this unit into an array, the voltage-controlled topological phase change can obtain different numbers of "on" and "off" channels, thereby realizing the detection of electric fields of different sizes.

[0004] On the other hand, phase-selective synthesis of low-dimensional materials is also a hot topic of current research. In existing material preparation technologies, the required materials and specified structures can be synthesized in a directional manner, among which chemical vapor deposition is a commonly used method for preparing sensors. In the past decade, chemical vapor deposition has played an important role in the field of high-purity functional materials. Through the deposition of vapor phase doping, the physical properties of materials can be precisely controlled. Summary of the invention

[0005] The present invention realizes the manipulation of internal electrons based on the topological phase change of the quantum spin Hall effect insulator material controlled by electric field, and provides a transient voltage detection method, which can measure the transient voltage within the accuracy of the electronic response time.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a transient voltage detection method based on array-type quantum spin Hall effect insulator material, comprising the following steps:

[0007] S1. Use first-principles calculations to determine quantum spin Hall effect insulator materials with different band gaps and their structures, and analyze the behavior of electrons and holes near the Fermi level. On this basis, select quantum spin Hall effect insulator materials with the following properties: quantum spin Hall effect insulator materials are nanoscale materials that can be stacked by van der Waals forces; the band orbits near the Fermi level are easy to distinguish, such as using the energy levels of different elements to be distributed on different sides of the Fermi level (conduction band and valence band); the behavior of electrons and holes near the Fermi level has the basic characteristics of band inversion and non-trivial topology; the gap between the bottom of the conduction band and the top of the valence band of the band structure of a single-layer quantum spin Hall effect insulator material is between 0.01eV and 0.1eV.

[0008] S2. Use first-principles calculations to determine common layered insulator materials that are lattice-matched to it.

[0009] S3. Model a multilayer unit, stacking a quantum spin Hall effect insulator material with an ordinary layered material, with the distance between the two layers of quantum spin Hall effect material being no less than 20 nm. A multilayer material unit is a unit having multiple quantum spin Hall effect insulator materials alternately stacked, or only one quantum spin Hall effect insulator material repeatedly stacked. In addition, the stability of the multilayer unit is determined by calculating the phonon dispersion of the multilayer unit. Determine the performance parameters: (1) Edge area ratio: the ratio of the edge area of ​​the quantum spin Hall effect insulator material to the edge area of ​​the multilayer material. (2) Edge transmission channel: the unit energy gap size of the quantum spin Hall effect insulator material.

[0010] S4. Design array units and grow stable multilayer materials in an array using chemical vapor deposition sensors, and build a transient voltage detection device to test the performance of the sensor array.

[0011] The beneficial effects of the present invention are:

[0012] In response to the needs of transient voltage detection, the present invention uses an electric field to control the topological phase transition of non-trivial topological materials to manipulate the electronic behavior in the material, thereby realizing a method for detecting transient voltage. This is fundamentally different from the technology of using electric fields to achieve carrier depletion and thus control electronic behavior;

[0013] The detection speed of the present invention is equivalent to the electric field response time, and no longer depends on the speed of the directional movement of electrons in different materials under the action of the electric field. At the same time, it is designed as an array component, which has better stability and operability;

[0014] The present invention can be applied to some insulator materials having quantum spin Hall effect, such as the twisted metastable phase of transition metal chalcogenides. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the process of the present invention;

[0016] Figure 2 Schematic diagram of projected energy bands of the quantum spin Hall effect insulator material according to the elements in the present invention;

[0017] Figure 3 The vertical stacking mode of 1T′ phase molybdenum disulfide and boron nitride at the atomic level in Example 1 of the present invention;

[0018] Figure 4 A schematic diagram of the structure of a multilayer material unit in the present invention;

[0019] Figure 5 Schematic diagram of the array sensor in the present invention;

[0020] Figure 6 Schematic diagram of sensor performance test in the present invention. DETAILED DESCRIPTION

[0021] The following is a detailed description of the embodiments of the present invention. Although the present invention will be described and illustrated in conjunction with some specific embodiments, it should be noted that the present invention is not limited to these embodiments. On the contrary, modifications or equivalent substitutions made to the present invention should all be included in the scope of the claims of the present invention.

[0022] In addition, in order to better illustrate the present invention, numerous specific details are given in the following specific embodiments. It will be understood by those skilled in the art that the present invention can also be implemented without these specific details.

[0023] Example 1

[0024] Figure 1 The main process of the detection method is shown in the following, and the process is described in detail. Transition metal chalcogenides, chemical formula MX 2 (where M is a transition metal W or Mo, and X is a chalcogenide element Te, Se, S), its distorted metastable phase (1T′) is a typical quantum spin Hall effect insulator material, and also satisfies several other properties: the energy band orbits near the Fermi level are easily distinguishable. Figure 2 The typical projected band orbital distribution of quantum spin Hall effect insulators is shown in the figure. The valence band is mainly composed of metal d orbitals, and the conduction band is mainly composed of chalcogen p orbitals. The band inversion near the Fermi level is caused by the doubling of the period of the metal chain in the 1T′ structure, which reduces the metal d orbital to below the chalcogen p orbital, and the conduction band is located on a completely separate plane. At the same time, transition metal elements are different from chalcogen elements in that their band gap widths are also different. This provides a simple mechanism for controlling topological electronic properties by electric fields. A single layer of hexagonal boron nitride (h-BN) is an ordinary two-dimensional wide-bandgap semiconductor material. Because there is not only a strong covalent bond component between the N and B atoms in boron nitride, but also a certain ionic component, h-BN has excellent insulation and high-temperature dielectric properties. At the same time, the two conform to the lattice matching mechanism and can be stacked by van der Waals forces. Figure 3 The vertical stacking mode of 1T′ phase MoS2 and BN at the atomic level is demonstrated in Figure 4 A multi-layer cell stacking pattern is shown.

[0025] The unit edge transmission channel is defined as a single-layer quantum spin Hall effect insulator material with an energy gap of 0.01 eV. The edge area ratio parameters of multilayer units with different stacking methods are calculated differently. When a variety of transition metal sulfide compounds and hexagonal boron nitride are mixed and stacked, the edge area ratio is shown in formula (1.1):

[0026]

[0027] Where S QSH1 , S QSH2 represents the edge area of ​​different single-layer quantum spin Hall effect insulator materials, S 总 Represents the edge area of ​​the multilayer material.

[0028] When a transition metal chalcogenide and hexagonal boron nitride are mixed and stacked, the edge area ratio is shown in formula (1.2):

[0029]

[0030] Where N represents the number of layers of single-layer quantum spin Hall effect insulator material, S QSH1 represents the edge area of ​​the single-layer quantum spin Hall effect insulator material, S 总 Represents the edge area of ​​multi-layer materials. Other stacking methods have similar calculation methods.

[0031] After theoretical calculation, a multilayer material with stable phonon dispersion was obtained, and the two were stacked by chemical deposition. Depending on the stacking mode, the raw materials and deposition process required for chemical vapor deposition are also different. One method for preparing 1T' phase molybdenum disulfide is:

[0032] At a temperature of 750°C, add powdered 2H phase MoS2 into the CVD furnace, and pass Ar gas flow, potassium ions and hydrogen mixed gas through the CVD furnace. Potassium ions will destroy the crystal structure, causing the MoS2 lattice to rearrange and form metastable phases 1T phase and 1T' phase. MoS2 1T phase is usually unstable in an independent situation, and will spontaneously deform the lattice to form T' phase. By controlling the appropriate temperature and stable potassium ions, high-purity 1T' phase MoS2 can be obtained. Multilayer units are obtained by similar methods.

[0033] Array sensors require redesigning the model and deposition steps, and designing different arrays according to actual needs. In order to meet the sensitivity and accuracy requirements, different multi-layer units need to be arranged. Figure 5 An array arrangement is shown. Figure 6 The performance of the sensor is tested. During the test, the sensor is placed in an electric field of not less than 0.1V / nm and not more than 10V / nm. In different electric fields, the multilayer unit will have both "on" and "off" transmission channels, but the ratio of the two will be different, resulting in different information about the number of transmission channels fed back, thereby measuring the size of the electric field.

[0034] The unique features of the present invention mainly include:

[0035] (1) The present invention is based on the topological phase change of the material controlled by electric field to realize the manipulation of electrons in the material, thereby realizing the two states of "on" and "off". This is different from the technology of achieving the two states of "on" and "off" by depleting carriers through electric field in a diode.

[0036] (2) The present invention is an electric field induced topological phase transition, which can occur very quickly, equivalent to the electric field response time, which is fundamentally different from the directional movement of electrons in different materials according to the electric field.

[0037] (3) The present invention is an array-type component with better stability and operability.

[0038] It should be understood that the examples and implementation modes described in the present invention are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art may make various modifications or changes based on the examples and implementation modes described in the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A transient voltage detection method based on array-type quantum spin Hall effect insulator materials, It is characterized in that The following steps are involved: Step 1: Use first-principles calculations to determine quantum spin Hall effect insulator materials with different band gaps. Quantum spin Hall effect insulator materials are nanoscale materials that can be stacked by van der Waals forces. The gap between the bottom of the conduction band and the top of the valence band of the band structure of a single-layer quantum spin Hall effect insulator material is between 0.01eV and 0.1eV, and the band orbits near the Fermi level are distinguished by the energy levels of different elements distributed on both sides of the conduction band and the valence band, and have band inversion and non-trivial topological characteristics; at the same time, select ordinary layered insulator materials with lattice matching, which are nanomaterials that can be stacked by van der Waals forces and are single-layer hexagonal boron nitride (h-BN), calculate the band structure and analyze the behavior of electrons and holes near its Fermi level; Step 2: Through interlayer van der Waals interaction, the calculated quantum spin Hall effect insulator materials with different band gaps are lattice matched with ordinary insulator materials to build a multilayer material unit stacked in sequence. At the same time, the phonon dispersion of the multilayer material unit is calculated to detect its dynamic stability and determine the performance parameters. The performance parameters include: (1) edge area ratio: the ratio of the edge area of ​​the quantum spin Hall effect insulator material to the edge area of ​​the multilayer material; (2) edge transmission channel: the unit energy gap size of the quantum spin Hall effect insulator material; Step 3: Combine the stable multilayer material units into an array sensor, prepare them using chemical vapor deposition, and test the performance parameters of the sensor array.

2. The transient voltage detection method based on array-type quantum spin Hall effect insulator material according to claim 1, It is characterized in that The common insulator in step 2 is a nanomaterial that can be stacked by van der Waals forces, and the lattice matching is that the maximum strain of the lattice constants of different materials is within 5%, and the stacking is in-plane stacking, or vertical to the plane stacking, or a mixed stack of the two.

3. The transient voltage detection method based on array-type quantum spin Hall effect insulator material according to claim 1, It is characterized in that The distance between the two layers of materials with quantum spin Hall effect is no less than 20 nm.

4. The transient voltage detection method based on array-type quantum spin Hall effect insulator material according to claim 1, It is characterized in that A multilayer material unit has multiple quantum spin Hall effect insulator materials, or only contains one quantum spin Hall effect insulator material.

5. The transient voltage detection method based on array-type quantum spin Hall effect insulator material according to claim 1, It is characterized in that The electric field magnitude of the transient voltage is not less than 0.1 V / nm and not greater than 10 V / nm.

6. The transient voltage detection method based on array-type quantum spin Hall effect insulator material according to claim 1, It is characterized in that The sensor array is a multi-layer material unit.

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