CN110487455A - A kind of method that light auxiliary improves strain gauge sensitivity - Google Patents

Abstract

The invention relates to a method for improving the sensitivity of a stress sensor with light assistance, and belongs to the field of sensors. The invention adopts the light-assisted method to make the stress sensor based on the two-dimensional material be illuminated while the electrical properties are changed under the influence of the stress; as an auxiliary function, the light is used to inject additional carriers into the two-dimensional material, so that it can be generated under the stress. When deformed, the injected additional carriers can effectively adjust the height of the effective Schottky barrier between the electrode and the two-dimensional material, thereby achieving the purpose of improving the sensitivity of the stress sensor. The stress deforms the two-dimensional material, which will lead to a change in the energy band structure of the two-dimensional material, and a change in the Schottky barrier between the two-dimensional material and the contacting conductive electrode; the light-assisted method can be Two-dimensional materials inject additional carriers, and this process is also affected by stress; using the light-assisted method, the two stress responses can be superimposed, thereby improving the sensitivity of the stress sensor.

Description

A Light-Assisted Method for Improving the Sensitivity of Stress Sensors

technical field

The invention relates to the field of stress sensors and a method for light injection of carriers, in particular to a method for light-assisted improvement of the sensitivity of a stress sensor, which belongs to the field of sensors.

Background technique

A strain sensor is a sensor that measures the strain generated by the deformation of an object under force. The most traditional one is the resistance strain gauge type stress sensor, which can convert the deformation of the mechanical component due to stress into a change in resistance. After calibration of the resistance and deformation, the stress or deformation of the mechanical component can be known.

However, the sensitivity of traditional stress sensors is generally low, for example, the sensitivity (gauge factor, GF) of metal-based stress sensors is usually in the range of 1-5. However, the light-assisted method of this application can greatly improve the sensitivity of stress sensors based on _two -dimensional materials. For example, we have increased the stress sensitivity of SnS2 materials by 50 times in the laboratory, making GF more than 1000.

The method of light-assisted improvement of the sensitivity of the stress sensor mainly uses the principle of light injection of carriers to change the carrier concentration of the two-dimensional material itself and adjust the height of the contact barrier between the two-dimensional material and the electrode, while the deformation caused by the stress It will also affect this process, so that the sensitivity of the stress sensor will add an additional response factor, which is finally manifested as an increase in the sensitivity of the stress sensor.

Contents of the invention

The purpose of the present invention is to solve the problem of low sensitivity in the prior art, and provide a method for improving the sensitivity of a stress sensor with light assistance.

The purpose of the present invention is achieved through the following technical solutions.

A light-assisted method for improving the sensitivity of a stress sensor. The light-assisted method is used: the stress sensor based on a two-dimensional material is subjected to light while being affected by stress to change its electrical properties; the light acts as an auxiliary effect to increase the magnitude of the change in electrical properties. So as to achieve the purpose of improving the sensitivity of the stress sensor.

The specific physical principle is: the stress causes the two-dimensional material to deform, which will cause the energy band structure of the two-dimensional material to change, which is reflected in the change of the carrier concentration of the two-dimensional material, and the two-dimensional material and The change of the Schottky barrier between the contacting conductive electrodes; the photo-assisted method can inject additional carriers into the two-dimensional material, and this process is also affected by the stress; the photo-assisted method can be used to inject two The stress responses are superimposed to increase the sensitivity of the stress sensor.

The high-sensitivity stress sensor prepared by the above method includes: a two-dimensional material, a flexible substrate, a conductive electrode, a wire and a light source; the two-dimensional material is placed on the flexible substrate, and the conductive electrode is placed on the two-dimensional material and the flexible On the substrate; illuminate the part of the two-dimensional material with a light source; connect wires on the conductive electrode, so that the entire sensor can be easily connected to the electronic system.

The two-dimensional material refers to a material in a nanoscale range in one dimension (here, thickness). For example but not limited to these, including: SnS ₂ , SnS, SnSe ₂ , SnSe, GaSe, GeSe, WS ₂ , WSe ₂ , MoS ₂ , MoSe ₂ , VS ₂ , VSe ₂ , PtS ₂ , PtSe ₂ and graphene, etc. .

The flexible substrate is a substrate used to carry the two-dimensional material mentioned above, and its softness is an adjustable parameter. According to the different stress scenarios of the final planned application, materials with high softness should be used, such as but not limited to It is an organic elastic plastic; or a material with low softness is used, such as but not limited to memory metal elastic steel.

The construction of the conductive electrode refers to using any method to form the conductive electrode to partially cover and connect to the two-dimensional material. For example, but not limited to, a layer of metal is plated with a coating machine after forming a template by photolithography.

The conductive electrode refers to the ability to connect two or more terminals of the claimed material, so as to facilitate the connection of the claimed material into the electronic system. The material of the conductive electrode is an adjustable parameter, and the most suitable metal, alloy or other conductive substance for the stress sensor is selected according to the difference in contact barrier between different materials and the claimed material.

The link wire refers to the part that has the function of linking the sensor into the electronic system, and it is not necessary to have a wire, as long as the sensor can be connected to the electronic system.

The electronic system refers to an electronic system that can use the stress sensor to measure stress, apply bias voltage, and read and analyze feedback signals.

The light source refers to a device capable of emitting light. For example, but not limited to, it can be an LED light source, a laser light source, a fluorescent light source, etc., and the wavelength, light intensity, frequency, and whether it is continuous are all adjustable parameters. Material selection of the two-dimensional materials and conductive electrodes.

Description of drawings

Figure 1 is step 1, transferring the two-dimensional material to the flexible substrate;

Figure 2 is step 2, constructing a conductive electrode on the side with the two-dimensional material;

Figure 3 is step 3, connecting the sensor to the electronic system through wires;

Figure 4 is step 4, illuminating the two-dimensional material with a light source;

Fig. 5 is a simple three-dimensional view of the light-assisted stress sensor;

Fig. 6 is a simple side view of the light-assisted stress sensor;

Fig. 7 is the deformation state of 5 kinds of sensors enumerated;

Fig. 8 is a schematic diagram of the principle of light-assisted enhancement of the stress sensor;

Figure 9 is an experimental test case of the embodiment; Figure A is a schematic diagram of the sample's deformation with time increasing current variation curve under dark conditions; Figure B is a schematic diagram of the sample's deformation with time increasing current variation curve under light conditions; Figure C is Schematic diagram comparing the difference in sensitivity GF between samples in the dark and in the light.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention more clear, the solutions in the examples of the invention will be described in more detail below in conjunction with the accompanying drawings in the examples of the present invention. In the drawings, the same or similar symbols represent the same or similar elements or elements having the same or similar functions. The described examples are examples of some, but not all, of the invention.

The examples described below by referring to the figures are exemplary and are intended to explain the present invention and should not be construed as limitations of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention. The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In describing the present invention, it is to be understood that the terms "moderate", "reduced", "low level", "higher level", "lower level", "larger", "significantly" and "superimposed" The orientation, position or degree relationship of such knowledge is based on the orientation, position or degree relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific Orientation, construction and operation in a particular orientation, therefore, should not be construed as limiting the scope of the invention.

Example 1

A light-assisted method for improving the sensitivity of the stress sensor, as shown in Figures 5 and 6, adopts the light-assisted method: the stress sensor based on the two-dimensional material receives light while being affected by the stress and changes its electrical properties; the light acts as an auxiliary function, Injecting additional carriers into the two-dimensional material increases the magnitude of the change in electrical properties, thereby achieving the purpose of improving the sensitivity of the stress sensor.

The high-sensitivity stress sensor prepared by the above method includes: a two-dimensional material, a flexible substrate, a conductive electrode, a wire and a light source; the two-dimensional material is placed on the flexible substrate, and the conductive electrode is placed on the two-dimensional material and the flexible between the substrates; illuminate the two-dimensional material part with a light source; connect wires on the conductive electrodes, so that the entire sensor can be easily connected to the electronic system.

The working method of the high-sensitivity stress sensor is as follows:

As shown in FIG. 1 , in operation step 1, a piece of two-dimensional material is transferred to a piece of flexible substrate, for example, SnS ₂ material is transferred to a PDMS substrate here.

As shown in Figure 2, operation step 2 is to make a mask on the two-dimensional material, first form a suitable mask by ultraviolet etching, and then use vacuum evaporation to coat one side of the mask with A layer of Ti metal and a layer of Au metal, and then wash off the mask with acetone alcohol to form the required conductive electrodes. For ease of illustration, only the 2-terminal electrode is shown in the figure, and more complex electrode structures can also be used.

As shown in accompanying drawing 3, in operation step 3, connect the stress sensor into the electronic system with wires to facilitate the use of the device, connect the optical auxiliary sensor with wires to apply a specific bias voltage, and read the current flowing through on the instrument.

As shown in Figure 4, in operation step 4, a light source is used to provide auxiliary light to the two-dimensional material part, inject photogenerated carriers, change the electrical properties of the material itself, improve stress sensitivity, and prepare for stress sensing. Using light with a wavelength of 400nm and an energy density of 10mW/cm ² to irradiate the SnS ₂ material part, the current flowing through the material is greatly increased.

As shown in FIG. 7, there are five basic deformation modes of the light-assisted stress sensor, and all five forms will bring stress to the stress sensor. The left side is a simple side view of the light-assisted stress sensor, only the larger flexible substrate part is drawn, and the two-dimensional material is above the flexible substrate by default. The deformation method from top to bottom on the right is described in the text in the figure.

As shown in Figure 8, a simple description of the principle of light-assisted enhancement of the sensitivity of the stress sensor, when a certain bias voltage is applied to the two-dimensional material, the current flowing through the two-dimensional material is at a moderate level, and when the stress is applied , the current will decrease to a low level, which is the basic principle of the traditional stress sensor; when the two-dimensional material is assisted by light, the initial current of the two-dimensional material itself will increase to a higher level, when subjected to When stress is applied, the current drops to a lower level. Because the light-assisted method has more relationship between light injected carriers and stress than the traditional stress sensor, therefore, the light-assisted method can additionally superimpose the response of light to stress, which can improve the stress sensor. sensitivity.

As shown in Figure 9, the test material is SnS ₂ , and Figure A is the current variation curve of the sample under dark conditions, and the deformation increases from 0 to 3.123% with time. According to calculations, it can be known that under dark conditions, the The sensitivity is only 20.6; Figure B is the current change curve of the sample under light conditions, and the deformation increases from 0 to 2.031% with time. According to the calculation, the sensitivity of this sample can reach 960.1 under the light condition; Figure C is a comparison of the SnS ₂ The difference in the sensitivity GF of the sample under the dark and light, it can be seen that the light magnifies the sensitivity by 48 times.

The specific description above further elaborates the purpose, technical solution and beneficial effect of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not used to limit the protection of the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included within the protection scope of the present invention.

Claims (9)

1. a kind of method that light auxiliary improves strain gauge sensitivity, it is characterised in that: use light auxiliary law: making based on two dimension The strain gauge of material is being occurred to receive illumination while electrical properties change by stress influence；Illumination is made as auxiliary With injecting additional carrier for two-dimensional material, be allowed to when being generated deformation by stress, the additional carriers of the injection The height of effective Schottky barrier between electrode and two-dimensional material can be effectively adjusted, so that it is bright to reach raising strain gauge spirit The purpose of degree.

2. using the highly sensitive strain gauge of the method as described in claim 1 preparation, it is characterised in that: include: two dimension Material, flexible substrate, conductive electrode, conducting wire and light source；The two-dimensional material is placed in flexible substrate, and the conductive electrode is set Between two-dimensional material and flexible substrate；With light source lighting two-dimensional material part；The connecting wire on conductive electrode makes entirely to pass Sensor facilitates in access electronic system.

3. the method as described in claim 1, it is characterised in that: the two-dimensional material includes: SnS₂、SnS、SnSe₂、SnSe、 GaSe、GeSe、WS₂、WSe₂、MoS₂、MoSe₂、VS₂、VSe₂、PtS₂、PtSe₂And graphene.

4. the method as described in claim 1, it is characterised in that: the light source includes: LED light source, laser light source, fluorescence light Source.

5. sensor as claimed in claim 2, it is characterised in that: the flexible substrate includes organic elastoplastic or memory Metallic elastic steel.

6. sensor as claimed in claim 2, it is characterised in that: the building method of the conductive electrode includes: photoetching process shape One layer of metal is plated with coating machine at after template.

7. sensor as claimed in claim 2, it is characterised in that: the conductive electrode includes: metal or alloy.

8. sensor as claimed in claim 2, it is characterised in that: the light source includes: LED light source, laser light source, fluorescence light Source.

9. sensor as claimed in claim 2, it is characterised in that: the two-dimensional material includes: SnS₂、SnS、SnSe₂、SnSe、 GaSe、GeSe、WS₂、WSe₂、MoS₂、MoSe₂、VS₂、VSe₂、PtS₂、PtSe₂And graphene.