阅读说明：本技术 一种基于二维材料量子隧穿的高灵敏压力传感器 (High-sensitivity pressure sensor based on two-dimensional material quantum tunneling ) 是由 于孟今 于 2021-06-23 设计创作，主要内容包括：本发明涉及压力传感领域,具体提供了一种基于二维材料量子隧穿的高灵敏压力传感器。本发明中,钉扎层、势垒层、自由层构成磁隧道结。应用时,应用固定磁场作用于本发明；压力作用在受力层上。通过测量具有压力时和未施加压力时,钉扎层和自由层之间电阻的差异,确定待测压力。在本发明中,受力层压缩二维材料层,使得二维材料层产生相变或形变,从而改变二维材料层的导电特性和量子隧穿特性,从而改变钉扎层和自由层之间的磁隧道结电阻。因为钉扎层和自由层之间的磁隧道结电阻严重地依赖于其间的二维材料层的导电特性或量子隧穿特性,所以本发明具有压力探测灵敏度高的优点。(The invention relates to the field of pressure sensing, and particularly provides a high-sensitivity pressure sensor based on two-dimensional material quantum tunneling. In the invention, the pinning layer, the barrier layer and the free layer form a magnetic tunnel junction. When in application, a fixed magnetic field is applied to the invention; pressure acts on the stressed layer. The pressure to be measured is determined by measuring the difference in resistance between the pinned and free layers with and without pressure applied. In the invention, the stress layer compresses the two-dimensional material layer to cause phase change or deformation of the two-dimensional material layer, so that the conductive property and the quantum tunneling property of the two-dimensional material layer are changed, and the magnetic tunnel junction resistance between the pinning layer and the free layer is changed. The present invention has an advantage of high pressure detection sensitivity because the magnetic tunnel junction resistance between the pinned layer and the free layer is heavily dependent on the conductive characteristics or quantum tunneling characteristics of the two-dimensional material layer therebetween.)

1. The high-sensitivity pressure sensor based on two-dimensional material quantum tunneling is characterized by comprising an antiferromagnetic layer, a pinning layer, a two-dimensional material layer, a free layer and a stress layer, wherein the antiferromagnetic layer is made of hard magnetic antiferromagnetic material, the pinning layer is arranged on the antiferromagnetic layer, the pinning layer is made of metal or semimetal with high spin polarizability, the two-dimensional material layer is arranged on the pinning layer, the free layer is arranged on the two-dimensional material layer, the free layer is made of soft magnetic material with weak magnetic anisotropy, and the stress layer is arranged on the free layer.

2. The high-sensitivity pressure sensor based on two-dimensional material quantum tunneling of claim 1, wherein: the two-dimensional material layer is made of molybdenum disulfide.

3. The two-dimensional material quantum tunneling based highly sensitive pressure sensor of claim 2, wherein: and holes are formed in the free layer at the interface of the two-dimensional material layer and the free layer.

4. The high-sensitivity pressure sensor based on two-dimensional material quantum tunneling of claim 3, wherein: and piezoelectric materials are arranged in the holes.

5. The high-sensitivity pressure sensor based on two-dimensional material quantum tunneling of claim 3, wherein: the hole is internally provided with a piezomagnetic material.

6. The high-sensitivity pressure sensor based on two-dimensional material quantum tunneling of claim 1, wherein: the two-dimensional material layer is a graphene composite layer, and the graphene composite layer comprises a graphene layer and a carbon nanotube layer.

7. The high-sensitivity pressure sensor based on two-dimensional material quantum tunneling of claim 6, wherein: the carbon nanotube layer is disposed on the graphene layer, and the graphene layer is disposed on the pinning layer.

8. The two-dimensional material quantum tunneling based highly sensitive pressure sensor of claim 7, wherein: the graphene layer is arranged on the carbon nano tube layer.

9. The two-dimensional material quantum tunneling based highly sensitive pressure sensor of claim 8, wherein: also included are particles of piezoelectric material disposed on the second graphene layer.

10. The two-dimensional material quantum tunneling based highly sensitive pressure sensor of claim 9, wherein: the second graphene layer is corrugated.

Technical Field

The invention relates to the field of pressure sensing, in particular to a high-sensitivity pressure sensor based on two-dimensional material quantum tunneling.

Background

The pressure sensor is a sensor for converting mechanical quantities such as weight, load, pressure and the like into an electric signal. Pressure sensors have wide applications in the fields of vehicles, aircraft, household appliances, industrial control, and the like. Although the pressure sensor based on the optical fiber or the optical principle has an advantage of high sensitivity, the pressure sensor based on the optical fiber or the optical principle requires a light source and a light detector. Such devices are complex and costly. Although conventional electrical pressure sensors have been widely used in industry, the sensitivity of these conventional electrical pressure sensors is low and cannot meet the requirements of aerospace and precision instruments. That is, as the technology advances, the detection sensitivity of the current pressure sensor cannot meet the demand, and a pressure sensing technology based on a new principle needs to be explored.

Disclosure of Invention

In order to solve the problems, the invention provides a high-sensitivity pressure sensor based on two-dimensional material quantum tunneling, which comprises an antiferromagnetic layer, a pinning layer, a two-dimensional material layer, a free layer and a stress layer, wherein the antiferromagnetic layer is made of hard magnetic antiferromagnetic material, the pinning layer is arranged on the antiferromagnetic layer, the pinning layer is made of metal or semimetal with high spin polarizability, the two-dimensional material layer is arranged on the pinning layer, the free layer is arranged on the two-dimensional material layer, the free layer is made of soft magnetic material with weak magnetic anisotropy, and the stress layer is arranged on the free layer.

Further, the material of the two-dimensional material layer is molybdenum disulfide.

Furthermore, at the interface of the two-dimensional material layer and the free layer, a hole is formed in the free layer.

Furthermore, the hole is provided with a piezoelectric material.

Further, the hole is provided with a piezomagnetic material therein.

Further, the two-dimensional material layer is a graphene composite layer, and the graphene composite layer comprises a graphene layer and a carbon nanotube layer.

Further, a carbon nanotube layer is disposed on the graphene layer, and the graphene layer is disposed on the pinning layer.

Still further, the graphene layer comprises a second graphene layer, and the second graphene layer is arranged on the carbon nano tube layer.

Still further, the graphene layer further comprises particles of piezoelectric material, and the particles of piezoelectric material are arranged on the second graphene layer.

Further, the second graphene layer is corrugated.

The invention has the beneficial effects that: the invention provides a high-sensitivity pressure sensor based on two-dimensional material quantum tunneling. In the invention, the pinning layer, the barrier layer and the free layer form a magnetic tunnel junction. When in application, a fixed magnetic field is applied to the invention; pressure acts on the stressed layer. The pressure to be measured is determined by measuring the difference in resistance between the pinned and free layers with and without pressure applied. In the invention, the stress layer compresses the two-dimensional material layer to cause phase change or deformation of the two-dimensional material layer, so that the conductive property and the quantum tunneling property of the two-dimensional material layer are changed, and the magnetic tunnel junction resistance between the pinning layer and the free layer is changed. The present invention has an advantage of high pressure detection sensitivity because the magnetic tunnel junction resistance between the pinned layer and the free layer is heavily dependent on the conductive characteristics or quantum tunneling characteristics of the two-dimensional material layer therebetween. In addition, the invention is based on the traditional electricity, has simple signal processing, small device size and convenient integration.

The present invention will be described in further detail below with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic diagram of a high-sensitivity pressure sensor based on two-dimensional material quantum tunneling.

Fig. 2 is a schematic diagram of yet another high-sensitivity pressure sensor based on two-dimensional material quantum tunneling.

In the figure: 1. an antiferromagnetic layer; 2. a pinning layer; 3. a two-dimensional material layer; 4. a free layer; 5. a stressed layer; 6. and (4) holes.

Detailed Description

To further explain the technical means and effects of the present invention adopted to achieve the intended purpose, the following detailed description of the embodiments, structural features and effects of the present invention will be made with reference to the accompanying drawings and examples.

Example 1

The invention provides a high-sensitivity pressure sensor adopting quantum tunneling of a two-dimensional material, which comprises an antiferromagnetic layer 1, a pinning layer 2, a two-dimensional material layer 3, a free layer 4 and a stress layer 5, as shown in figure 1. The material of the two-dimensional material layer 3 is molybdenum disulfide. The material of the antiferromagnetic layer 1 is a hard magnetic antiferromagnetic material, and specifically, the material of the antiferromagnetic layer 1 is IrMn, PtMn, FeMn. The pinned layer 2 is placed on the antiferromagnetic layer 1. The material of the pinning layer 2 is a metal or semimetal having high spin polarizability, and specifically, the material of the pinning layer 2 is Co, Fe, CoFe, CoFeB, CoFeAl alloy. A two-dimensional material layer 3 is placed on the pinned layer 2. The free layer 4 is disposed on the two-dimensional material layer 3. The number of the molybdenum disulfide layers in the two-dimensional material layer 3 is less than 10, so that under the action of pressure, the conductive property and the quantum tunneling property of the two-dimensional material layer 3 can be changed relatively more, and the sensitivity of pressure detection is improved. The stress layer 5 is placed on the free layer 4. The material of the free layer 4 is a soft magnetic material with weak magnetic anisotropy, and specifically, the material of the free layer 4 is a NiFe alloy, a CoFe alloy, or a CoFeB alloy. The material of the stress layer 5 is a non-magnetic material. The material of the stress layer 5 can be silicon dioxide. The stress layer 5 can be layered on the free layer 4, and the stress layer 5 can also be composed of a plurality of independent stress parts which are arranged on the free layer 4. The latter facilitates the connection of electrodes on the free layer 4 for testing. Whether the force-receiving portions have the same height or the same area is set according to the requirements, and is not limited herein.

In the present invention, the pinning layer 2, the barrier layer 3, and the free layer 4 constitute a magnetic tunnel junction. In general, a magnetic tunnel junction is a so-called junction element formed by sandwiching a nano-scale insulating layer between two ferromagnetic sheets. In ferromagnetic materials, due to quantum mechanical exchange, the 3d orbital localized electron band of ferromagnetic metals is cleaved, giving rise to different energy state densities for the spin-up and spin-down electrons near the fermi surface. The mechanism of quantum tunneling effect generated in the insulator is spin-dependent tunneling effect. The structure of the magnetic tunnel junction is generally a sandwich structure of ferromagnetic layer/nonmagnetic insulating layer/ferromagnetic layer. In the present invention, the pinned layer 2, the barrier layer 3, and the free layer 4 constitute a magnetic tunnel junction.

When in application, a fixed magnetic field is applied to the invention; the pressure to be measured acts on the force-bearing layer 5. The pressure to be measured is determined by measuring the difference in resistance of the magnetic tunnel junction between the pinned layer 2 and the free layer 4 with and without pressure applied. In the invention, the stress layer 5 compresses the two-dimensional material layer 3, so that the molybdenum disulfide generates phase change, thereby changing the conductive property and the quantum tunneling property of the molybdenum disulfide, and further changing the resistance between the pinning layer 2 and the free layer 4. The present invention has an advantage of high pressure detection sensitivity because the magnetic tunnel junction resistance between the pinned layer 2 and the free layer 4 is heavily dependent on the conductive characteristic or the quantum tunneling characteristic of molybdenum disulfide therebetween.

In addition, the invention is based on the traditional electricity, has simple signal processing, small device size and convenient integration. In addition, in the present invention, the pressure also changes the stress in the free layer 4, thereby changing the spin state in the free layer 4, thereby more changing the resistance between the pinned layer 2 and the free layer 3, thereby achieving more sensitive pressure detection.

Example 2

In addition to the embodiment 1, as shown in fig. 2, a hole 6 is provided in the free layer 4 at the interface between the two-dimensional material layer 3 and the free layer 4. That is, at the interface of the two-dimensional material layer 3 and the free layer 4, the surface of the free layer 4 has a recess portion that forms the hole 6 with the two-dimensional material layer 3. The holes 6 are arranged periodically. In this way, the contact area between the free layer 4 and the two-dimensional material layer 3 is smaller. At the contact, the two-dimensional material layer 3 is subjected to larger pressure, so that the conductive property and the quantum tunneling property of the molybdenum disulfide are changed more, the magnetic tunnel junction resistance between the pinning layer 2 and the free layer 4 is changed more, and the pressure detection with higher sensitivity is realized.

Example 3

In addition to embodiment 2, a piezoelectric material is provided in the hole 6. Preferably, the piezoelectric material fills the holes 6. In this way, under the action of pressure, electric charges are generated outside the piezoelectric material, and the electric charges change the conductive characteristic and the quantum tunneling characteristic of the molybdenum disulfide, so that the magnetic tunnel junction resistance between the pinning layer 2 and the free layer 4 is changed more, and the pressure detection with higher sensitivity is realized.

Example 4

On the basis of embodiment 2, the hole 6 is internally provided with a piezomagnetic material. Preferably, the hole 6 is filled with a piezomagnetic material. In this way, under pressure, the permeability of the piezomagnetic material changes, thereby changing the spin state of the piezomagnetic material/free layer 4 composite in contact with the two-dimensional material layer 3, thereby changing the magnetic tunnel junction resistance between the pinned layer 2 and the free layer 4, thereby achieving higher sensitivity of pressure detection.

Example 5

On the basis of embodiment 1, the two-dimensional material layer 5 is a graphene composite layer. The graphene composite layer includes a graphene layer and a carbon nanotube layer. The carbon nanotube layer is disposed on the graphene layer, which is disposed on the pinning layer 2. The number of layers of graphene in the graphene layer is less than 10, so that under the action of pressure, the conducting property or the quantum tunneling property of the graphene layer can be changed relatively more, and the sensitivity of pressure detection is improved. The carbon nanotubes may be single-layered or multi-layered. Preferably, the carbon nanotube layer is a single layer, so that the interface between the carbon nanotube and the graphene layer is changed more under the action of pressure, thereby improving the sensitivity of pressure detection.

During the application, under the effect of waiting to measure the pressure, not only the inside stress of graphite alkene composite bed not only changes thereupon, and the thickness or the appearance of graphite alkene composite bed also change moreover to can change the quantum tunneling characteristic of graphite alkene layer composite bed more, thereby realize the pressure sensing of higher sensitivity.

Example 6

On the basis of embodiment 5, the graphene layer structure further comprises a second graphene layer, and the second graphene layer is arranged on the carbon nanotube layer. Thus, a second graphene layer, a carbon nanotube layer, and a graphene layer sandwich structure are formed, having an interface between two carbon nanotubes and graphene. Under the action of pressure, the appearance of the sandwich structure is changed more, so that the quantum tunneling characteristic of the sandwich structure is changed more, the magnetic tunnel junction resistance between the pinning layer 2 and the free layer 4 is changed more, and high-sensitivity pressure detection is realized.

Example 7

On the basis of embodiment 7, the graphene-based photovoltaic device further comprises piezoelectric material particles, and the piezoelectric material particles are placed on the second graphene layer. Piezoelectric material is a crystalline material that develops an electrical charge and voltage across its two end faces when subjected to a compressive force. The material of the piezoelectric material particles may be an inorganic piezoelectric material, such as piezoelectric crystals and piezoelectric ceramics; the material of the piezoelectric material particles may also be an organic piezoelectric material, such as an electropolymer such as polyvinylidene fluoride. Under pressure, charges appear on the piezoelectric material particles, and the charges change the Fermi level of the second graphene layer, so that the quantum tunneling characteristic of the second graphene layer is changed. Therefore, the present embodiment can change the magnetic tunnel junction resistance between the pinned layer 2 and the free layer 4 more at the same pressure, thereby achieving higher sensitivity of pressure sensing.

Further, the second graphene layer is corrugated. Therefore, under the action of pressure, the appearance or the interface state between the second graphene layer and the carbon nano tube layer is changed more, the quantum tunneling characteristic between the second graphene layer and the carbon nano tube layer is changed more, the magnetic tunnel junction resistance between the pinning layer 2 and the free layer 4 is changed more, and the pressure sensing with higher sensitivity is realized.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.