A broadband spectral bionic adaptive vision sensor based on thermoelectric materials and a preparation method thereof

Abstract

The present invention discloses a wide-spectrum bionic adaptive vision sensor based on thermoelectric materials and a preparation method thereof, belonging to the field of bionic electronic information technology. The sensor includes a substrate, a dielectric layer, a semiconductor channel layer, a source electrode and a drain electrode; the dielectric layer is formed on the substrate, the source electrode and the drain electrode are located on the dielectric layer and are respectively distributed at both ends of the dielectric layer, and the semiconductor channel layer is located between the source electrode and the drain electrode; the semiconductor channel layer is made of quasi-one-dimensional optoelectrothermal material Nb3Se 12 I crystal. Among them, the semiconductor channel layer has optoelectrothermal characteristics and is used to realize photoelectric conversion and signal modulation. The sensor realizes light intensity visual adaptive modulation and a wide-spectrum response range.

Description

Technical Field

[0001] The present invention belongs to the field of bionic electronic information technology, and particularly relates to a wide-spectrum bionic adaptive vision sensor based on thermoelectric materials and a preparation method thereof. Background Art

[0002] Visual perception is a key sensory mechanism in humans and other vertebrates, providing over 80% of the environmental information for brain processing. With the rapid development of sensory functions and artificial intelligence systems, the demand for electronic components that can simulate biological visual perception is increasing. In particular, these devices need to be able to adapt to fluctuating ambient light intensities by dynamically adjusting current signals, thereby maintaining a clear and consistent imaging state, which is crucial for the visual system. However, traditional electronic components often suffer from increased power consumption and reduced efficiency due to complex hardware structures and algorithms.

[0003] In recent years, artificial adaptive systems based on single-device structures of low-dimensional materials have developed rapidly. For example, a bionic vision sensor based on a bilayer molybdenum disulfide phototransistor, by intentionally introducing charge trap states on the MoS2 surface, these trap states can store optical information and, at different gate voltages, can capture or remove electrons in the channel, thereby dynamically adjusting the conductivity of the device and achieving dynamic modulation of photosensitivity under different light conditions. At the same time, using the photoinduced phase separation of CsPb(Br 1-x I x )3 perovskite, a heterojunction based on perovskite and MoS2 was prepared. The phase separation under visible light irradiation causes I and Br to separate into iodine-rich and bromine-rich independent domains, significantly changing the photocurrent in the phototransistor, thus realizing the simulation of the human sensory adaptation process. Nevertheless, there is currently no report on a simple two-terminal transistor device based on optothermoelectric materials for simulating human visual adaptive recognition.

[0004] In summary, developing a bionic vision adaptive recognition sensor with a simple structure and an intuitive working principle can not only provide a new perspective for visual adaptation research but also be of great significance for the development of future artificial intelligence vision systems. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a wide-spectrum bionic adaptive vision sensor based on thermoelectric materials and a preparation method thereof, achieving light intensity visual adaptive modulation and a wide-spectrum response range.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material, comprising a substrate, a dielectric layer, a semiconductor channel layer, a source electrode and a drain electrode;

[0008] The dielectric layer is formed on the substrate, the source electrode and the drain electrode are located on the dielectric layer and are respectively distributed at both ends of the dielectric layer, and the semiconductor channel layer is located between the source electrode and the drain electrode;

[0009] The semiconductor channel layer is made of a quasi-one-dimensional optoelectrothermal material Nb3Se 12 I crystal.

[0010] In an embodiment, the substrate is any one of a silicon-based substrate, a gallium arsenide substrate and a silicon carbide substrate;

[0011] The dielectric layer is any one of aluminum oxide, hafnium dioxide and silicon dioxide.

[0012] In an embodiment, the thickness of the dielectric layer is 285 nm.

[0013] In an embodiment, both the source electrode and the drain electrode are composed of a cadmium layer and a gold layer.

[0014] In an embodiment, the thickness of the cadmium layer is 5-10 nm, and the thickness of the gold layer is 60-100 nm.

[0015] The present invention also provides a preparation method of a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material, comprising the following steps:

[0016] S1: Take Nb powder, Se powder and I2 crystal as raw materials according to the stoichiometric ratio of each element in the Nb3Se 12 I crystal, and synthesize the optoelectrothermal material Nb3Se 12 I crystal by chemical vapor transport method;

[0017] S2: Form a dielectric layer on the substrate to obtain a substrate with a dielectric layer;

[0018] S3: Use the optoelectrothermal material Nb3Se 12 I crystal to prepare a semiconductor channel layer, and form a substrate with a semiconductor channel layer and a dielectric layer;

[0019] S4: Spin-coat a photoresist on the substrate with a semiconductor channel layer and a dielectric layer, and then form a source electrode and a drain electrode at both ends of the substrate with a semiconductor channel layer and a dielectric layer by using a maskless lithography technique, a resistive thermal evaporation technique and a semiconductor lift-off process in sequence, so as to obtain a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material.

[0020] In an embodiment, in the S1, the process parameters of the chemical vapor transport method are as follows:

[0021] The transfer agent is I2; the content of the transfer agent is 2 mg / cm 3 ;

[0022] The temperature at the evaporation end is 600 °C, the temperature at the growth end is 480 °C, the growth time is 14 days, and the heating rate is 1 - 2 °C / min.

[0023] In one embodiment, in S3, the process of synthesizing a substrate with a semiconductor channel layer and a dielectric layer using the photothermal electric material Nb3Se 12 I crystal is as follows:

[0024] Place the photothermal electric material Nb3Se 12 I crystal on the tape, and through multiple folding and uncovering operations, peel the photothermal electric material Nb3Se 12 I crystal, and attach the peeled photothermal electric material Nb3Se 12 I crystal to a substrate with a dielectric layer to obtain a substrate with a semiconductor channel layer and a dielectric layer.

[0025] In one embodiment, in S4, the process of spin-coating photoresist includes low-speed spin-coating and high-speed spin-coating carried out in sequence; the process conditions for low-speed spin-coating are 500 rmp / 5 s, and the process conditions for high-speed spin-coating are 3000 rmp / 30 s.

[0026] In one embodiment, in S4, both the source electrode and the drain electrode are composed of a cadmium layer and a gold layer;

[0027] The process parameters of the resistive thermal evaporation technology are as follows:

[0028] The evaporation rate of the cadmium layer is The evaporation rate of the gold layer is The vacuum degree in the evaporation chamber is maintained at 5×10 -5 Pa - 5×10 -4 Pa.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material. By utilizing the synergistic effect of the thermoelectric properties and radiative heat properties of the optoelectrothermal material, wide-spectrum bionic adaptive vision sensing is achieved. Compared with other bionic adaptive vision sensors relying on ion modulation, this sensor has the characteristics of a simple adjustment mechanism, a short dynamic adjustment time, and a wide detectable spectral range, which is crucial for future applications in artificial intelligence vision systems. The sensor can exhibit different current response behaviors according to different light intensities. In a low-light environment, the current remains constant, mimicking the behavior of the human eye in soft light; in a bright environment, the current first rises and then slowly stabilizes at a higher level, similar to the adjustment response of the human eye in bright light; in an over-bright environment, the current behavior is similar to that in bright light, but finally maintains at a lower level, simulating the situation where the human eye is visually blurred due to the decreased sensitivity of photoreceptor cells under extremely strong light. The wide-spectrum bionic adaptive vision sensor of the present invention can effectively achieve the adaptation to light intensity and the wide-spectrum detection function, and plays an important role in promoting the development of future artificial intelligence vision systems.

[0031] The present invention also provides a preparation method for the above-mentioned wide-spectrum bionic adaptive vision sensor based on a thermoelectric material. First, an optoelectrothermal crystal material Nb3Se 12 I with a quasi-one-dimensional nanowire structure is prepared by chemical vapor transport method, and then this material is fabricated into a two-terminal transistor sensor through mechanical exfoliation and the techniques of maskless lithography and resistive thermal evaporation. The present invention utilizes the optoelectrothermal properties and radiative heat properties of the optoelectrothermal crystal material to achieve a wide-spectrum bionic adaptive vision sensor.

[0032] The above-mentioned optoelectrothermal material Nb3Se 12 I is prepared by a simplified synthesis method, which can effectively produce an optoelectrothermal material with a quasi-one-dimensional nanowire structure. This optoelectrothermal material not only has a small volume but also is convenient to be integrated into microelectronic devices, which is of great significance for the development of the integration of artificial intelligence systems. Description of the Drawings

[0033] Figure 1 is the optical image of the quasi-one-dimensional optoelectrothermal material Nb3Se 12 I crystal prepared in Example 1 of the present invention;

[0034] Figure 2 is the scanning electron microscope image of the two-terminal transistor sensor based on the quasi-one-dimensional optoelectrothermal material Nb3Se 12 I prepared in Example 1 of the present invention;

[0035] Figure 3 is the two-terminal transistor sensor based on the quasi-one-dimensional optoelectrothermal material Nb3Se 12The curve of photocurrent versus time of the dual-terminal transistor sensor of I when the laser power is 124 μW, which is used to simulate the situation of the human eye exposed to a soft light environment;

[0036] Figure 4 For the quasi-one-dimensional optoelectrothermal material Nb3Se prepared in Example 1 of the present invention 12 The curve of photocurrent versus time of the dual-terminal transistor sensor of I when the laser power is 482 μW, which is used to simulate the situation of the human eye exposed to a bright light environment;

[0037] Figure 5 For the quasi-one-dimensional optoelectrothermal material Nb3Se prepared in Example 1 of the present invention 12 The curve of photocurrent versus time of the dual-terminal transistor sensor of I when the laser power is 725 μW, which is used to simulate the situation of the human eye exposed to an overly bright light environment;

[0038] Figure 6 For the quasi-one-dimensional optoelectrothermal material Nb3Se prepared in Example 1 of the present invention 12 Schematic diagram of different state stages of the dual-terminal transistor sensor of I imitating the adaptive process of the human eye;

[0039] Figure 7 For the quasi-one-dimensional optoelectrothermal material Nb3Se prepared in Example 1 of the present invention 12 Mechanism diagram of the dual-terminal transistor sensor of I imitating the adaptive process of the human eye;

[0040] Figure 8 Figures (a) and (b) in are respectively the dual-terminal transistor sensor of I prepared in Example 1 of the present invention based on the quasi-one-dimensional optoelectrothermal material Nb3Se 12 The dual-terminal transistor sensor of I simulates the adaptive imaging process of the human eye under bright and overly bright environmental light;

[0041] Figure 9 For the quasi-one-dimensional optoelectrothermal material Nb3Se prepared in Example 1 of the present invention 12 Schematic diagram of the light response of the dual-terminal transistor sensor of I varying with time in the visible to mid-infrared range. Detailed implementation manners

[0042] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art for the present invention. In case of conflict, the definition in this specification shall prevail.

[0043] The theories or mechanisms described and disclosed herein, whether right or wrong, shall not in any way limit the scope of the present invention, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0044] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0045] In this article, unless otherwise specified, terms such as "comprising", "including", "containing", "having", or similar terms cover the meanings of "consisting of" and "consisting essentially of". For example, "A comprises a" covers the meanings of "A comprises a and others" and "A only comprises a".

[0046] In this article, for the sake of concise description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0047] The present invention provides a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material and a preparation method thereof.

[0048] On the one hand, a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material is provided, including a substrate, a dielectric layer, a semiconductor channel layer, a source electrode and a drain electrode; the dielectric layer is formed on the substrate, the source electrode and the drain electrode are located on the dielectric layer and are respectively distributed at both ends of the dielectric layer, and the semiconductor channel layer is located between the source electrode and the drain electrode; the semiconductor channel layer is made of a quasi-one-dimensional optoelectrothermal material Nb3Se 12 I crystal. Among them, the preparation material of the semiconductor channel layer has optoelectrothermal properties and can adjust the current response under different illumination conditions, so as to realize the adaptive adjustment of light intensity. Among them, the substrate is used to support the entire sensor structure; the dielectric layer is formed on the substrate and is used to isolate the electrodes; the source electrode and the drain electrode are located on the dielectric layer and are distributed at both ends; the semiconductor channel layer is located between the source electrode and the drain electrode and has optoelectrothermal characteristics, and is used to realize photoelectric conversion and signal modulation.

[0049] The above-mentioned substrate can be any one of a silicon-based substrate, a gallium arsenide substrate, and a silicon carbide substrate. The dielectric layer can be any one of aluminum oxide, hafnium dioxide, and silicon dioxide. Both the source electrode and the drain electrode are composed of a cadmium layer and a gold layer.

[0050] In one embodiment, preferably, the substrate is a silicon substrate, which provides excellent mechanical stability and compatibility. The dielectric layer is silicon dioxide, which is a non-conductive material, effectively isolating the source and drain electrodes and protecting the underlying substrate.

[0051] The thickness of the above dielectric layer is 285 nm; the thickness of the cadmium layer is 5 - 10 nm, and the thickness of the gold layer is 60 - 100 nm.

[0052] In one embodiment, the source and drain are composed of a 5-nm-thick cadmium layer and a 60-nm-thick gold layer, providing good conductivity and stable chemical properties.

[0053] In one embodiment, the broad spectral range of the bionic adaptive vision sensor is 405 nm - 4060 nm.

[0054] On the other hand, a preparation method of the above broad-spectrum bionic adaptive vision sensor based on thermoelectric materials is provided, including the following steps:

[0055] S1: Take Nb powder, Se powder and I2 crystal as raw materials according to the stoichiometric ratio of each element in Nb3Se 12 I crystal, and synthesize the optoelectrothermal material Nb3Se 12 I crystal by chemical vapor transport method; among them, the process parameters of the chemical vapor transport method are as follows:

[0056] The transport agent is I2; the content of the transport agent is 2 mg / cm 3 ;

[0057] The temperature of the evaporation end is 600 °C, the temperature of the growth end is 480 °C, the growth time is 14 days, and the heating rate is 1 - 2 °C / min.

[0058] S2: Form a dielectric layer on the substrate to obtain a substrate with a dielectric layer.

[0059] S3: Use the optoelectrothermal material Nb3Se 12 I crystal to prepare a semiconductor channel layer, and form a substrate with a semiconductor channel layer and a dielectric layer; specifically, place the optoelectrothermal material Nb3Se 12 I crystal on the tape, and through multiple folding and uncovering operations, peel the optoelectrothermal material Nb3Se 12 I crystal, and attach the peeled optoelectrothermal material Nb3Se 12 I crystal to the substrate with a dielectric layer to obtain a substrate with a semiconductor channel layer and a dielectric layer.

[0060] S4: Spin coat photoresist on a substrate with a semiconductor channel layer and a dielectric layer. Subsequently, use maskless lithography technology, resistive thermal evaporation technology, and semiconductor lift-off process to form a source electrode and a drain electrode at both ends of the substrate with a semiconductor channel layer and a dielectric layer respectively, thereby obtaining a broadband biomimetic adaptive vision sensor based on a thermoelectric material. Among them, the process of spin coating photoresist includes a low-speed spin coating at 500 rmp / 5 s and a high-speed spin coating at 3000 rmp / 30 s in sequence. In addition, the process parameters of the resistive thermal evaporation technology are as follows: the evaporation rate of the cadmium layer is The evaporation rate of the gold layer is The vacuum degree in the evaporation chamber is maintained at 5×10 -5 Pa to 5×10 -4 Pa.

[0061] Specifically, the steps of the above preparation method are as follows:

[0062] (1) Synthesize a photothermoelectric material:

[0063] Weigh Nb powder, Se powder, and I2 crystal with a purity of 99.999% according to the stoichiometric ratio of each element in Nb3Se 12 I as raw materials for synthesizing Nb3Se 12 I crystal. Among them, I2 is used as a transport agent and is sealed in a vacuum quartz tube. Place it in a two-zone tube furnace and synthesize the photothermoelectric material Nb3Se 12 I crystal through chemical vapor transport method;

[0064] (2) Prepare a broadband biomimetic adaptive vision sensor based on the photothermoelectric material:

[0065] Form a dielectric layer on the substrate to obtain a substrate with a dielectric layer;

[0066] Place the photothermoelectric material synthesized in step (1) on the transparent tape, fold it in half, then unfold it, repeat about 5 times, and then stick it on the substrate. Gently press the tape with the material by hand, and after five minutes, peel it off from the substrate. The peeled material is left on the substrate to form a substrate with a semiconductor channel layer and a dielectric layer;

[0067] Subsequently, spin coat photoresist on the substrate with a semiconductor channel layer and a dielectric layer, use a Heidelberg maskless lithography machine to prepare a hollow electrode pattern, and then prepare a transistor sensor with a two-terminal structure having a source electrode and a drain electrode through resistive thermal evaporation technology and semiconductor lift-off process.

[0068] Preferably, in step (1), the synthesized photothermoelectric material Nb3Se 12 I of the semiconductor channel layer has a quasi-one-dimensional crystal structure.

[0069] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0070] In the following embodiments, conventional instruments and equipment in the art are used. For the experimental methods without specific conditions noted in the following embodiments, they are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. Various raw materials are used in the following embodiments. Unless otherwise stated, commercially available products are used, and their specifications are the conventional specifications in the art. In the specification of the present invention and the following embodiments, unless otherwise specified, "%" represents weight percentage, "parts" represents weight parts, and the ratio represents weight ratio.

[0071] Example 1

[0072] This example provides a wide-spectrum bionic adaptive vision sensor based on thermoelectric materials and its preparation method.

[0073] The above sensor sequentially includes: a silicon-based substrate for supporting the entire sensor structure; a silicon dioxide dielectric layer formed on the silicon-based substrate for isolating electrodes; a source electrode and a drain electrode located on the silicon dioxide dielectric layer and distributed at both ends; a semiconductor channel layer located between the source electrode and the drain electrode. The semiconductor channel layer has optoelectrothermal properties and is used to achieve photoelectric conversion and signal modulation. The semiconductor channel layer is made of quasi-one-dimensional optoelectrothermal material Nb3Se 12 I crystal.

[0074] The preparation method of the above sensor includes the following steps:

[0075] Step 1: Synthesize optoelectrothermal materials

[0076] Weigh Nb powder, Se powder, and I2 crystal with a purity of 99.999% according to the stoichiometric ratio of each element in Nb3Se 12 I as raw materials for synthesizing Nb3Se 12 I crystal. Among them, 2 mg / cm 3 of I2 is used as a transport agent. Seal and melt the raw materials in a vacuum quartz tube, and place the vacuum quartz tube in a two-temperature zone tube furnace to synthesize the material by chemical vapor transport method.

[0077] In Step 1, the masses of the raw materials of Nb powder, Se powder, and I2 crystal are 1 g, 3.6 g, and 0.6 g respectively. The size of the vacuum quartz tube is an inner diameter of 2 cm and a height of 20 cm, and the vacuum degree is 5×10 -4Pa. The temperatures of the double-temperature zone tube furnace are set as the evaporation end temperature of 600 °C and the growth end temperature of 480 °C respectively, the growth time is 14 days, and the heating rate is 1.3 °C / min.

[0078] The quasi-one-dimensional crystal material Nb3Se 12 I's optical image is as Figure 1 shown.

[0079] Step 2: Prepare a double-terminal transistor vision adaptive sensor based on the optothermal electric material

[0080] (1): Place the optothermal electric material Nb3Se 12 I prepared in Step 1 on the Scotch transparent tape of 3M Company, fold it in half, then uncover it, repeat about 5 times, and then stick it on the silicon substrate with 285 nm thick silicon dioxide. Gently press the tape stuck on the silicon substrate by hand, and uncover it from the silicon substrate after 5 min. The peeled Nb3Se 12 I material is retained on the silicon substrate to obtain a substrate with a semiconductor channel layer and a dielectric layer.

[0081] (2): Subsequently, spin-coat AZ5214 photoresist on the silicon substrate (substrate with a semiconductor channel layer and a dielectric layer) retaining the Nb3Se 12 I material and then bake the photoresist; among them, the spin-coating parameters are 500 rmp / 5 s, 3000 rmp / 30 s, and the baking parameters are 90 s of heating on a 100 °C hot plate.

[0082] (3): Use a Heidelberg maskless lithography machine to prepare a hollow electrode pattern, and set the Dose and Defocus to 100 mJ / cm 2 and 0 respectively.

[0083] (4): Then deposit a 5 nm Cr layer and a 60 nm Au layer respectively through resistive thermal evaporation technology, and set their deposition rates to and The vacuum degree in the evaporation chamber is maintained at 5×10 -5 Pa.

[0084] (5): After the deposition is completed, immerse it in acetone heated to 50 °C and keep it for 30 min, and then gently blow the deposited layer with a disposable dropper. The deposited layer with the photoresist part will be peeled off, so that only the double-terminal electrode pattern deposited layer remains on the silicon substrate.

[0085] Subsequently, the silicon-based substrate was taken out and immersed in an isopropyl alcohol solution for 1 minute to remove the acetone on its surface, and then rinsed thoroughly with deionized water to obtain a transistor sensor with a two-terminal structure having a source and a drain (a broadband bionic adaptive vision sensor based on a thermoelectric material), and its scanning electron microscope image is as Figure 2 shown.

[0086] Example 2

[0087] This example provides a broadband bionic adaptive vision sensor based on a thermoelectric material and a preparation method thereof.

[0088] The above-mentioned sensor sequentially includes: a gallium arsenide substrate for supporting the entire sensor structure; an aluminum oxide dielectric layer formed on the gallium arsenide substrate for isolating electrodes; a source and a drain located on the aluminum oxide dielectric layer and distributed at both ends; a semiconductor channel layer located between the source and the drain, the semiconductor channel layer having optoelectrothermal characteristics for realizing photoelectric conversion and signal modulation, and the semiconductor channel layer is made of a quasi-one-dimensional optoelectrothermal material Nb3Se 12 I crystal.

[0089] The preparation method of the above-mentioned sensor includes the following steps:

[0090] Step 1: Synthesize the optoelectrothermal material

[0091] Weigh Nb powder, Se powder, and I2 crystal with a purity of 99.999% according to the stoichiometric ratio of each element in Nb3Se 12 I as the raw materials for synthesizing Nb3Se 12 I crystal, where 2 mg / cm 3 of I2 is used as a transport agent. Seal and melt the raw materials in a vacuum quartz tube, and place the vacuum quartz tube in a two-zone tube furnace to synthesize the material by chemical vapor transport method.

[0092] In Step 1, the masses of the raw materials of Nb powder, Se powder, and I2 crystal are 1 g, 3.6 g, and 0.6 g respectively. The size of the vacuum quartz tube is an inner diameter of 2 cm and a height of 20 cm, and the vacuum degree is 5×10 -4 Pa. The temperatures of the two-zone tube furnace are set with an evaporation end temperature of 600 °C and a growth end temperature of 480 °C, the growth time is 14 days, and the heating rate is 1 °C / min.

[0093] The optical image of the quasi-one-dimensional crystal material Nb3Se 12 I after growth is as Figure 1 shown.

[0094] Step 2: Prepare a two-terminal transistor vision adaptive sensor based on the optoelectrothermal material

[0095] (1): Place the optoelectrothermal material Nb3Se synthesized in Step 1 12 I on the Scotch transparent tape of 3M Company, fold it in half, then unfold it, repeat about 5 times, and then stick it on the gallium arsenide substrate with 285 nm thick aluminum oxide. Gently press the tape stuck on the gallium arsenide substrate by hand. After 5 minutes, peel it off from the gallium arsenide substrate, and the peeled Nb3Se 12 I material remains on the gallium arsenide substrate, obtaining a substrate with a semiconductor channel layer and a dielectric layer.

[0096] (2): Subsequently, spin-coat AZ5214 photoresist on the gallium arsenide substrate (substrate with a semiconductor channel layer and a dielectric layer) retaining the Nb3Se 12 I material and then bake the photoresist; among them, the spin-coating parameters are 500 rmp / 5 s, 3000 rmp / 30 s, and the baking parameters are heating on a hot plate at 100 °C for 90 s.

[0097] (3): Use the Heidelberg maskless lithography machine to prepare a hollow electrode pattern, and set the Dose and Defocus to 100 mJ / cm 2 and 0 respectively.

[0098] (4): Then deposit a 10 nm Cr layer and a 100 nm Au layer respectively by resistive thermal evaporation technology, and set their deposition rates to and The vacuum degree in the evaporation chamber is maintained at 5×10 -4 Pa.

[0099] (5): After the deposition is completed, immerse it in acetone heated to 50 °C and keep it for 30 minutes. Then gently blow the deposited layer with a disposable rubber head dropper, and the deposited layer with the photoresist part will be peeled off, so that only the deposited layer of the two-terminal electrode pattern remains on the gallium arsenide substrate.

[0100] Then take out the gallium arsenide substrate, soak it in isopropyl alcohol solution for 1 minute to remove the acetone on its surface, and then rinse it with deionized water to obtain a transistor sensor with a two-terminal structure having a source electrode and a drain electrode (a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material).

[0101] Example 3

[0102] This example provides a wide-spectrum bionic adaptive vision sensor based on a thermoelectric material and its preparation method.

[0103] The above-mentioned sensor sequentially includes: a silicon carbide substrate for supporting the entire sensor structure; a hafnium dioxide dielectric layer formed on the silicon carbide substrate for isolating electrodes; a source electrode and a drain electrode located on the hafnium dioxide dielectric layer and distributed at both ends; a semiconductor channel layer located between the source electrode and the drain electrode. The semiconductor channel layer has optothermoelectric properties and is used to achieve photoelectric conversion and signal modulation. The semiconductor channel layer is made of a quasi-one-dimensional optothermoelectric material Nb3Se 12 single crystal.

[0104] The preparation method of the above-mentioned sensor includes the following steps:

[0105] Step 1: Synthesize the optothermoelectric material

[0106] Weigh Nb powder, Se powder, and I2 single crystal with a purity of 99.999% respectively according to the stoichiometric ratio of each element in Nb3Se 12 single crystal as the raw materials for synthesizing Nb3Se 12 single crystal. Among them, 2 mg / cm 3 of I2 is used as a transport agent. Seal the raw materials in a vacuum quartz tube and place the vacuum quartz tube in a two-temperature-zone tube furnace to synthesize the material by chemical vapor transport method.

[0107] In Step 1, the masses of the raw materials of Nb powder, Se powder, and I2 single crystal are 1 g, 3.6 g, and 0.6 g respectively. The size of the vacuum quartz tube is an inner diameter of 2 cm and a height of 20 cm, and the vacuum degree is 5×10 -4 Pa. The temperatures of the two-temperature-zone tube furnace are set as the evaporation end temperature of 600 °C and the growth end temperature of 480 °C respectively. The growth time is 14 days, and the heating rate is 2 °C / min.

[0108] The optical image of the quasi-one-dimensional crystal material Nb3Se 12 single crystal after growth is as Figure 1 shown.

[0109] Step 2: Prepare a two-terminal transistor vision adaptive sensor based on the optothermoelectric material

[0110] (1): Place the optothermoelectric material Nb3Se 12 single crystal synthesized in Step 1 on the Scotch transparent tape of 3M Company, fold it in half, and then unfold it. Repeat about 5 times. Then stick it on the silicon carbide substrate with a 285-nm-thick hafnium dioxide. Gently press the tape stuck on the silicon carbide substrate by hand. After 5 minutes, peel it off from the silicon carbide substrate. The peeled Nb3Se 12 single crystal material is retained on the silicon carbide substrate to obtain a substrate with a semiconductor channel layer and a dielectric layer.

[0111] (2): Subsequently, on the retained Nb3Se 12After spin - coating AZ5214 photoresist on a silicon carbide substrate of Material I (a substrate with a semiconductor channel layer and a dielectric layer), post - bake the photoresist. Among them, the spin - coating parameters are 500 rmp / 5 s, 3000 rmp / 30 s, and the post - bake parameters are heating on a hot plate at 100 °C for 90 s.

[0112] (3): Use Heidelberg's maskless lithography machine to prepare a hollow electrode pattern, and set the Dose and Defocus to 100 mJ / cm 2 and 0 respectively.

[0113] (4): Then deposit a 5 - nm Cr layer and a 60 - nm Au layer respectively through resistive thermal evaporation technology, and set their deposition rates to and The vacuum degree in the evaporation chamber is maintained at 5×10 -5 Pa.

[0114] (5): After deposition, immerse it in acetone heated to 50 °C and keep it for 30 min. Then, gently blow the deposition layer with a disposable dropper. The deposition layer with the photoresist part will be peeled off, so that only the deposition layer of the two - terminal electrode pattern remains on the silicon carbide substrate.

[0115] Subsequently, take out the silicon carbide substrate, soak it in isopropyl alcohol solution for 1 min to remove the acetone on its surface, and then rinse it with deionized water to obtain a transistor sensor with a two - terminal structure of source and drain (a broadband bionic adaptive vision sensor based on thermoelectric materials).

[0116] Simulation test

[0117] Simulation test one: Simulate the human eye's adaptive process under different light intensities

[0118] Human visual adaptation not only depends on the transient response to light intensity but also requires dynamic adaptation to constant light stimuli.

[0119] Place the prepared transistor vision - adaptive sensor with a two - terminal structure under a microscope integrated with a 532 - nm wavelength laser, connect the source and drain to a Keithley 4200A semiconductor tester respectively, and irradiate the laser at the interface between the drain and the Nb3Se 12 I material.

[0120] By adjusting the power of the laser, further observe the change of current with time in the two - terminal structure transistor to simulate the human eye's adaptive process under different light intensities.

[0121] Specifically, a 532-nm laser with powers of 124, 482, and 725 μW was used to irradiate the drain of a transistor vision adaptive sensor with a two-terminal structure, and the time-dependent photocurrent in the sensor was measured to simulate the adaptive responses of the human eye to soft, bright, and over-bright light environments, respectively.

[0122] Nb3Se 12 As an excellent photothermoelectric material, Nb3Se

[0123] I can perform self-driven light response under zero bias voltage. The time-varying photocurrent generated by a broadband spectral biomimetic adaptive vision sensor based on a thermoelectric material exhibits significantly different behaviors under constant light stimuli of different intensities. Figure 3 Shown as

[0124] Under soft light (laser power of 124 μW) irradiation, the photocurrent of the sensor remains constant at 2 nA over time, similar to the sensitivity of the retina to soft light, and no visual adaptation process is required to clearly observe objects, as Figure 4 Shown.

[0125] When exposed to bright light (laser power of 482 μW), the photocurrent generated by the device exhibits a dynamic current decay over time and finally reaches equilibrium at 4 nA, as Figure 4 Shown. This is the same as the adaptive regulation behavior of the retina under continuous bright light irradiation, and it takes some time to adapt to gradually see objects clearly. Moreover, the equilibrium current value under bright light is higher than that under soft light, which is consistent with the fact that the human eye can see clearer images in a bright environment.

[0125] When exposed to over-bright light (laser power of 725 μW), the change in the current value is similar to that in a bright environment, but the equilibrium current value (1.9 nA) is less than the 2 nA observed under soft light, and the time to reach equilibrium is significantly shortened, as Figure 5 Shown. This is similar to the phenomenon that when the human eye is exposed to an over-bright environment for a long time, the sensitivity of photoreceptor cells decreases and the regulatory ability weakens.

[0126] Analysis of the mechanism principle of the biomimetic human eye adaptation process under different light intensities:

[0127] The present invention also studied the internal mechanism of the photocurrent adaptive change of the photothermoelectric material Nb3Se 12 I.

[0128] As Figure 6 Shown, under 532-nm laser irradiation, a typical visual adaptation curve undergoes four stages: (Ⅰ) dark state, (Ⅱ) peak state after light stimulation, (Ⅲ) adaptation process, and (Ⅳ) establishment of a new equilibrium state.

[0129] The synergistic effect of the photothermal-electric effect and the radiative heat effect is the main mechanism of bionic vision adaptation of a broadband spectral bionic adaptive vision sensor based on a thermoelectric material. The schematic diagrams of the mechanisms in different stages are as shown in Figure 7 Figure. In the absence of light stimulation, the main response of the device in stage (Ⅰ) is a weak dark current, which is equivalent to the closed-eye state. Once illuminated, the radiative heat effect occurs, increasing the number of hot carriers in the material and thus enhancing the photocurrent. Further analysis shows that when one end of the device is irradiated with a laser, an instantaneous spatial temperature gradient (dT / dX > 0) is generated. This gradient induces the photothermal-electric effect, and the spatial temperature difference is converted into voltage, thereby enhancing the photocurrent. Therefore, in stage (Ⅱ), the sharp output current generated after light stimulation is the result of the synergistic effect of the photothermal-electric effect and the radiative heat effect. The peak value of the spatial temperature gradient at the moment of laser irradiation generates the largest thermoelectric potential difference, which drives the hot carriers to generate photocurrent. As the temperature distribution becomes more uniform, the spatial temperature gradient and the thermoelectric potential difference decrease accordingly, resulting in a gradual decrease in the photocurrent in the third stage. As the hot carriers accumulate and the thermoelectric potential difference decreases, this process continues and finally forms a dynamically balanced photocurrent in the fourth stage. In this stage, the spatial temperature gradient is the smallest and the radiative heat effect is the largest, jointly forming an equilibrium state. The greater the laser power, the smaller the final spatial temperature gradient, the smaller the thermoelectric potential difference, and the lower the generated equilibrium photocurrent. This situation is similar to the response of the human eye in an overly bright environment. On the contrary, irradiating the device with soft light (low-power laser) generates a temperature gradient that does not change with time, and the radiative heat effect is not obvious, thus maintaining a constant photocurrent without an adaptive process. This discovery emphasizes the key role of the photothermal-electric effect in the function of the Nb3Se 12 I photosensor, as well as their potential similarity to human visual adaptation.

[0130] Based on Nb3Se 12 I, the quasi-one-dimensional bionic vision adaptive sensor simulates several key visual adaptation processes of the human retina.

[0131] Simulation Test 2: Simulating the adaptive imaging process of the human eye under bright and overly bright environmental light

[0132] Place the prepared transistor sensor with a two-terminal structure at the same position used to simulate the adaptive process of the human eye under different light intensities, and simultaneously place a mask plate that can move in two-dimensional directions on the incident laser light path. Control the on and off of the laser by moving the mask plate, analogizing the imaging process of different pixel points, and used to simulate the adaptive imaging process of the human eye under environmental light.

[0133] Specifically, a movable mask plate characterized by the letter "X" is placed on the incident laser path. Here, the hollowed-out parts corresponding to the letter allow the laser to pass through, while the mask parts block the light beam. At I ds =-1 nA (representing the lowest visibility), the dark current condition is established. At I ds =4.7 nA, the clear imaging condition is established. Figure 8 The adaptive imaging process of the device under different lighting conditions is shown.

[0134] As Figure 8 shown in Figure a in the middle, when exposed to bright light (laser power of 482 μW), the device initially shows a glaring image of "X", which gradually transitions to a clear image over time, reflecting the visual adaptation observed on the human retina.

[0135] Conversely, in an over-bright environment (laser power of 725 μW), the device first shows a glaring "X" pattern, which eventually darkens over time, as Figure 8 shown in Figure b in the middle. This adaptation mode is similar to the process in which long-term exposure of the human retina to an over-bright environment causes a decrease in the sensitivity of photoreceptor cells, resulting in a darker image.

[0136] At zero bias, the response spectral range of the device is measured by irradiating the device with lasers of different wavelengths, as Figure 9 shown. Based on the quasi-one-dimensional optothermoelectric material Nb3Se 12 I, the two-terminal transistor sensor shows broadband detection ability from visible to near-infrared light (405 nm - 4060 nm), which means that Nb3Se 12 I may be used for self-powered broadband detection and visual adaptation in future intelligent devices.

[0137] In summary, the above tests have demonstrated the successful development of a photoelectric sensor using Nb3Se 12 I nanowires with a quasi-one-dimensional structure, which can effectively simulate the adaptation behavior of the human eye under various light conditions. The device utilizes a synergistic mechanism combining the optothermoelectric effect and the radiative heat effect to achieve dynamic adaptation to continuous light stimuli. This mechanism enables self-powered broadband detection (405 nm - 4060 nm), significantly reducing power consumption while maintaining high device performance. In addition, this method also greatly improves the adaptation speed, effectively meeting the requirements for fast adaptation in future artificial intelligence vision applications. The above content not only deepens people's understanding of the mechanism of simulating human visual adaptation, but also promotes the development of precision optical sensors and artificial vision systems, having a profound impact on the design and application of artificial intelligence vision systems in future technical fields.

[0138] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution in accordance with the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A wide spectrum bionic adaptive visual sensor based on thermoelectric materials, characterized in that: It includes a substrate, a dielectric layer, a semiconductor channel layer, a source electrode and a drain electrode; The dielectric layer is formed on the substrate, the source electrode and the drain electrode are located on the dielectric layer and are respectively distributed at two ends of the dielectric layer, the semiconductor channel layer is located between the source electrode and the drain electrode, and the two ends of the semiconductor channel layer are respectively in contact with the source electrode and the drain electrode; The semiconductor channel layer adopts a photothermoelectric material Nb3Se with a quasi-one-dimensional nanowire structure 12 I crystal made.

2. The wide spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 1, characterized in that: The substrate is any one of a silicon-based substrate, a gallium arsenide substrate and a silicon carbide substrate; The dielectric layer is any one of aluminum oxide, hafnium dioxide and silicon dioxide.

3. The wide spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 1, characterized in that: The thickness of the dielectric layer is 285 nm.

4. The wide spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 1, characterized in that: The source electrode and the drain electrode are both composed of a cadmium layer and a gold layer.

5. The wide spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 4, characterized in that: The thickness of the cadmium layer is 5-10 nm, and the thickness of the gold layer is 60-100 nm.

6. A method for preparing a wide-spectrum bionic adaptive visual sensor based on thermoelectric materials according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: According to Nb3Se 12 The stoichiometric ratio of each element in the I crystal is shown in Figure 1. Nb powder, Se powder and I2 crystal are used as raw materials to synthesize the photothermoelectric material Nb3Se by chemical vapor transport method. 12 I crystal; S2: forming a dielectric layer on the substrate to obtain a substrate having a dielectric layer; S3: Using photothermoelectric material Nb3Se 12 I. preparing a semiconductor channel layer by crystallization to form a substrate having a semiconductor channel layer and a dielectric layer; S4: Spin-coat a photoresist on a substrate having a semiconductor channel layer and a dielectric layer, and then sequentially use maskless photolithography, resistive thermal evaporation, and a semiconductor stripping process to form a source and a drain at both ends of the substrate having a semiconductor channel layer and a dielectric layer, respectively, to obtain a wide-spectrum bionic adaptive visual sensor based on thermoelectric materials.

7. The method for preparing a wide-spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 6, characterized in that: In S1, the process parameters of the chemical vapor transport method are as follows: The transfer agent is I2; the content of the transfer agent is 2 mg / cm 3 ; The temperature of the evaporation end is 600°C, the temperature of the growth end is 480°C, the growth time is 14 days, and the heating rate is 1~2°C / min.

8. The method for preparing a wide-spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 6, characterized in that: In S3, the photothermoelectric material Nb3Se 12 The process of crystal synthesis of a substrate having a semiconductor channel layer and a dielectric layer is as follows: Photothermoelectric material Nb3Se 12 I crystal is placed on the tape, and the photothermoelectric material Nb3Se is folded and uncovered several times. 12 I crystal is peeled off, and the peeled photothermoelectric material Nb3Se 12 The I crystal is attached to a substrate having a dielectric layer to obtain a substrate having a semiconductor channel layer and a dielectric layer.

9. The method for preparing a wide-spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 6, characterized in that: In S4, the process of spin coating the photoresist includes low-speed spin coating and high-speed spin coating performed sequentially; the process conditions of the low-speed spin coating are 500 rmp / 5 s, and the process conditions of the high-speed spin coating are 3000 rmp / 30 s.

10. The method for preparing a wide-spectrum bionic adaptive visual sensor based on thermoelectric materials according to claim 6, characterized in that: In S4, the source electrode and the drain electrode are both composed of a cadmium layer and a gold layer; The process parameters of the resistive thermal evaporation technology are as follows: The evaporation rate of the cadmium layer was 0.2 Å / s, the evaporation rate of the gold layer was 0.4 Å / s, and the vacuum degree in the evaporation chamber was maintained at 5×10 -5 Pa~5×10 -4 Pa.

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