Two-dimensional indium selenide optical sensor with motion trail recognition function and preparation method of two-dimensional indium selenide optical sensor

Abstract

The invention discloses a two-dimensional indium selenide optical sensor with a motion trail recognition function and a preparation method thereof. The light sensor device comprises a SiO2 / Si substrate, a gamma-InSe semiconductor light absorption layer located on the substrate and asymmetric Au electrode structures arranged at the two ends of the light absorption layer. A gamma-InSe semiconductor material with a non-centrosymmetric structure is selected, and an asymmetric electrode configuration design is combined, so that the device generates a photo-pyroelectric effect and a photo-thermoelectric effect under the condition of temperature change caused by illumination, and remarkable positive and negative pyroelectric response peak current is formed in a zero-bias self-driven mode. The device can directly analyze and reconstruct the motion trail of an object according to the dynamic behavior of the reverse attenuation current after light removal, does not need to depend on an external calculation unit, and achieves the function of integrating light perception, information storage and motion trail calculation in a single device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of two-dimensional semiconductor optoelectronic devices and specifically relates to a two-dimensional indium selenide light sensor with a motion trajectory recognition function and a preparation method thereof. BACKGROUND

[0002] Under the background of contemporary technology dominated by intelligence and informatization, real-time motion perception has become the core capability of dynamic scene understanding, and is widely used in key fields such as visual monitoring, traffic management and autonomous driving. The key challenge to realize this function is to build a new sensor architecture that can synchronously encode and process dynamic motion spatiotemporal features. At present, the traditional imaging system based on complementary metal oxide semiconductor (CMOS) generally adopts modular design, separating image sensing and backend processing, which leads to high energy consumption, high redundancy and response delay when processing large-scale image data. In sharp contrast to this is the efficient processing mechanism of the biological visual system. Taking the mammalian retina as an example, it not only has high sensitivity in light signal capture, but also can dynamically encode visual information in the time-space dimension through a multi-layer neural network, and efficiently transmit the optimized features to the brain visual center for high-level processing. This mechanism not only guarantees image quality, but also significantly reduces information redundancy, thereby supporting the biological system to respond quickly and accurately to environmental changes.

[0003] Although current research on visual bionic sensors has made some progress, most work still focuses on the simulation of static image processing functions, such as noise suppression, long-term memory and image enhancement based on neuromorphic algorithms, and has not fully realized real-time and efficient processing of dynamic visual information. In addition, existing sensors rely on complex hardware structures and control algorithms, and generally have low system integration, high energy consumption and large size. Their working mechanisms are mostly limited to single physical processes such as carrier capture or ion migration, making it difficult to meet the requirements of future motion perception and artificial vision systems for high speed, precision and parallel processing capabilities. In view of the above challenges, the present application introduces two-dimensional material γ-InSe as a photosensitive layer to construct a new sensor. This material has ultra-high carrier mobility, non-centrosymmetric crystal structure and wide spectral response, and shows significant advantages in photo- pyroelectric effect. Under light conditions, the material changes the polarization intensity due to temperature changes, which can produce positive and negative bidirectional response peak current. Combined with the photo- pyroelectric effect, it can realize the recognition of motion trajectory in the visible to near-infrared light range in a self-driven mode. This mechanism effectively simulates the information processing process in biological vision, supports dynamic perception and processing of image visual information in multiple environments, and further realizes the detection, recognition, understanding and tracking of targets in complex scenes. Its performance can be comparable to or even better than that of micro-vision systems, and has great potential as a core element of the next generation of artificial vision systems. SUMMARY

[0004] The purpose of this invention is to solve the problem of separation between detection and information processing in motion recognition by optical vision sensors based on two-dimensional materials. It provides a two-dimensional indium selenide optical sensor with motion trajectory recognition function and its preparation method, providing a new approach for the integrated and intelligent development of high-performance, low-energy-consumption bionic vision systems.

[0005] The two-dimensional indium selenide optical sensor with motion trajectory recognition function includes, from bottom to top: a substrate, an InSe nanolayer, and a gold electrode layer.

[0006] The gold electrode layer is located at both ends of the InSe nanolayer, forming a double-ended gold electrode device.

[0007] The substrate is SiO2 / Si or PDMS.

[0008] The InSe nanolayer is two-dimensional γ-InSe;

[0009] The InSe nanolayer has a thickness of 30–40 nm.

[0010] The SiO2 / Si mentioned above is a Si substrate covered with a 300 nm SiO2 layer.

[0011] A two-dimensional indium selenide optical sensor with motion trajectory recognition function and its fabrication method include the following steps:

[0012] 1) Fabrication of a gold electrode layer;

[0013] a. Cut SiO2 / Si into squares and clean them;

[0014] b. Spin-coating photoresist onto the SiO2 / Si substrate;

[0015] c. Draw the required electrode pattern and import it into a maskless lithography machine for exposure and development;

[0016] d. 0.03 g of gold is deposited on the substrate by vapor deposition, the photoresist is washed off, and the substrate is dried to obtain a patterned gold electrode on the SiO2 / Si substrate;

[0017] 2) Transfer the InSe nanolayer onto another SiO2 / Si substrate;

[0018] 3) The gold electrode prepared in step 1) is attached to the top of the InSe nanolayer to prepare the upper gold electrode layer;

[0019] 4) After removing any residual PVA adhesive, blow dry.

[0020] 5) Anneal at 120 °C for 10 min in a vacuum environment.

[0021] The method for fabricating a two-dimensional indium selenide biomimetic visual light sensor with motion trajectory recognition is characterized in that: the InSe nanolayer in step 2) is prepared by mechanical exfoliation.

[0022] Step 4) The gold electrode layer is prepared by spin-coating the gold electrode prepared in step 1) with an 8% PVA solution. After the PVA solution forms a film, the gold electrode is peeled off with the help of PDMS and attached to the InSe nanolayer to prepare the gold electrode layer.

[0023] Another objective of this invention is to provide the application of a two-dimensional indium selenide biomimetic optical sensor in artificial vision.

[0024] The artificial vision mentioned above is used for motion trajectory recognition. The motion trajectory recognition is achieved by creating a current mapping image based on the change of the It curve of the reverse peak when the light is removed in the photo-pyroelectric phenomenon.

[0025] This invention provides a method for fabricating and applying a two-dimensional indium selenide (InSe) photosensor with motion trajectory recognition. The method includes: 1) obtaining an InSe nanolayer with a thickness of approximately 30 nm on a PDMS substrate using mechanical lift-off technology; 2) obtaining a 30 nm thick Au electrode using photolithography and thermal evaporation techniques; and 3) fabricating a double-ended gold-InSe device using PVA solution and PDMS-assisted transfer technology. Results show that, under the influence of thermal changes caused by light and temperature, the self-driven photosensor based on γ-InSe can effectively simulate biological visual functions.

[0026] To achieve photo-thermoelectric and photothermoelectric effects, this invention alters the polarization intensity of the material by applying / removing light and constructs asymmetric electrode contacts to influence the temperature difference across the electrodes during illumination, thereby generating a photo-thermoelectric effect. The contact between the electrodes and the two-dimensional material generates a built-in electric field that drives the separation of photogenerated carriers to produce a photocurrent. Furthermore, under full-spectrum light illumination, without relying on additional information processing units, a single device completes photoresponse, storage, and computation.

[0027] The beneficial effects of this invention are as follows: Indium selenide, a two-dimensional material with a non-centrosymmetric structure and narrow bandgap, is utilized in this invention. Therefore, the heat generated during the application and removal of light causes a change in polarization intensity, resulting in the release of polarization charge and generating a photo-thermoelectric effect. Simultaneously, by constructing an asymmetric contact between gold and indium selenide, the temperature difference across the electrodes during illumination is affected, thus inducing a photo-thermoelectric effect. The device can achieve a wide-band light response in the visible-near-infrared (400-900 nm) range in self-driven mode. Furthermore, the changes in illumination and the slowly changing pyroelectric current curves after the removal of illumination are used to simulate the trajectory contours formed by objects moving under different motion modes (such as translation and rotation). Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a two-dimensional indium selenide optical sensor with motion trajectory recognition based on the present invention;

[0029] Figure 2 These are the characterization results of the dual-ended two-dimensional indium selenide photosensor prepared in this invention. (a) Raman spectrum of the device; (b) SHG intensity and angle dependence of the fitted curve of the device;

[0030] Figure 3 This is the photocurrent variation curve of the dual-ended two-dimensional indium selenide photosensor prepared by the present invention at wavelengths of 400nm-900nm over time.

[0031] Figure 4 This is a schematic diagram of trajectory recognition and a current mapping image of the dual-end two-dimensional indium selenide photosensor prepared by the present invention. Detailed Implementation

[0032] Example 1: Fabrication of a two-dimensional indium selenide-based optical sensor

[0033] Please see the appendix Figure 1 A two-dimensional indium selenide (InSe) photosensitive sensor with motion trajectory recognition is disclosed. It comprises: a SiO2 / Si substrate, a dual-ended electrode, and a semiconductor material. The dual-ended electrode is an Au electrode, which is photolithographically etched onto the SiO2 / Si substrate. The semiconductor material is thermally released onto the SiO2 / Si substrate using a thermally released adhesive tape. The photolithographically etched gold electrode is deposited as a film using PVA and transferred to a sample with an InSe nanolayer using a thermally released adhesive tape. Finally, a dual-ended gold electrode-InSe device is constructed.

[0034] Example 2: Preparation of two-dimensional indium selenide semiconductor material

[0035] The preparation steps are as follows:

[0036] 1) Obtain InSe bulk material;

[0037] 2) Use commercial machinery to peel off special blue adhesive tape to repeatedly thin the bulk material;

[0038] 3) Obtain the target material on blue tape using heat-release PDMS tape;

[0039] 4) The material on the heat-release tape was heated to 90°C for 10 minutes using a two-dimensional material transfer platform to attach the InSe nanolayer on the heat-release tape to the SiO2 / Si substrate. 25 samples were transferred to the substrate in sequence.

[0040] Example 3: Fabrication of a two-dimensional indium selenide photosensitive sensor with motion trajectory recognition function

[0041] Step 1: Gold electrodes are deposited onto the SiO2 / Si substrate using maskless photolithography and thermal evaporation.

[0042] Step 2: Place 4 g of PVA particles, 46 ml of deionized water and a stir bar into a reagent bottle, and keep it on a hot plate at a speed of 600 r and a temperature of 100℃ for 24 h to prepare a PVA solution with a mass fraction of 8%.

[0043] Step 3: Spin-coat the PVA solution onto the gold electrode of SiO2 / Si. After the PVA solution has formed a film, peel off the gold electrode covered with the PVA film on the substrate using PDMS, and then attach it to the SiO2 / Si substrate with 25 InSe nanolayers by dry transfer.

[0044] Step 4: Immerse the prepared device in deionized water for 10 minutes to remove the PVA adhesive, and then dry the device with an air gun.

[0045] Step 5: Anneal the device in a vacuum environment at 120°C for 10 min to improve the contact quality of the device interface.

[0046] Performance Characterization and Testing of a Two-Dimensional Indium Selenide Photosensor with Motion Trajectory Recognition

[0047] Appendix Figure 1 This is a schematic diagram of the structure of the double-ended gold-γ-InSe device described in this invention. Under 488nm laser irradiation, the Raman spectrum of the device corresponds to... Figure 2 As shown in figure a, the graph displays 113, 176, and 223 cm. -1 There are three strong peaks at 199cm. -1 There is a weak peak at point A, corresponding to A. 1g 1 E 2g 1 A 1g 2 and A 1g 1 (LO) vibration mode. A 1g 1 The (LO) mode is generally considered an important characteristic of non-centrosymmetric structures; therefore, the InSe nanosheets prepared in this paper exhibit a non-centrosymmetric γ-phase structure and thus possess non-centrosymmetric properties. (See attached image) Figure 2Figure b shows the angle-dependent second harmonic emission (SHG) signal spectrum obtained under a pulsed laser with an excitation source of 1064 nm. The figure reveals a clear six-lobed structure at different rotation angles, with its intensity changing periodically with the rotation angle, further confirming the six-fold symmetry of the γ-InSe crystal structure. The Raman spectroscopy and SHG test results together indicate that the InSe material used in this invention is a γ-phase structure with significant second-order nonlinear optical properties, providing a material basis for the realization of the device's integrated optical sensing and information processing functionality.

[0048] Figure 3 This study reflects the photocurrent phenomenon of the device under different wavelengths of illumination in self-driven mode. Due to the narrow bandgap of indium selenide (InSe), a wide-band response from visible light to near-infrared is achieved. Specifically, in the absence of light stimulation, dipoles in γ-InSe oscillate around their equilibrium positions, resulting in only dark current. Under illumination, the device's instantaneous temperature rises, causing dipole perturbation, changing polarization intensity, and releasing polarization charge, generating a pyroelectric current. Simultaneously, the thermoelectric effect within the channel directly converts the temperature difference into voltage, producing a net charge of directional transport after superposition, i.e., the thermoelectric current. Furthermore, without applied voltage, photoexcitation generates electron-hole pairs that separate under the influence of the Schottky's built-in electric field, forming a photovoltaic current. When illumination remains constant, the temperature of the light spot is constant, the pyroelectric current disappears, and the thermoelectric current decreases with thermal equilibrium, eventually resulting in only the photocurrent. When illumination is removed, the device's instantaneous temperature decreases, generating a reverse pyroelectric current, while the existing spatial temperature gradient also generates a thermoelectric current. Finally, as the device reaches a new thermal equilibrium, the spatial temperature gradient is eliminated, and the device returns to its initial state. The photo-thermoelectric effect disappears, and the current becomes only dark current. Therefore, the current exhibits a peak-and-peak curve in both positive and negative responses, as shown below. Figure 3 As shown.

[0049] Figure 4This paper demonstrates the ability of a two-dimensional indium selenide (InSe) photosensor array to identify the trajectory of an object under different motion modes, including the corresponding current response mapping images. The motion types are divided into two main categories: translation and rotation, with the moving object represented by the letter "F". At the initial time t0, the object is stationary. By comparing the position and shape changes of "F" at consecutive time points (e.g., t1 and t2), its motion mode can be effectively identified. Translational motion includes four directions: right, left, down, and up, and proceeds at a constant speed (1 step / Δt). The unit duration (Δt) is defined as the time interval between adjacent image frames, and the unit step size is the actual distance between the centers of adjacent pixels. Taking rightward motion as an example, the speed can be slow (1 step / Δt) or fast (2 steps / Δt), and the motion mode can be uniform or accelerated, depending on whether the displacement changes within the consecutive Δt time interval. Furthermore, the object also has the ability to rotate clockwise or counterclockwise. These different motion modes can be identified by the drain current (Id) of the corresponding channel of the γ-InSe photosensor array. ds Effective capture. At the initial time t0, the original image state of object "F" is stored in the device array. When the object moves out of a certain pixel area, based on the photo-pyroelectric effect, the current generated by that pixel exhibits a regular decay behavior, that is, the current gradually decreases over time after the light stimulus is removed, and the current value of the later frame is always higher than that of the previous frame. By superimposing the current responses of multiple frames, the complete motion trajectory contour can be clearly reconstructed. The I of each sensing unit... ds The values ​​are represented by pixel brightness, differentiated from light gray to dark gray, and recorded at continuous time points (e.g., t1, t2), ultimately forming a unique current distribution spectrum corresponding to each motion pattern. All current data are measured at zero bias (V). ds Data was acquired under conditions of 0 V. This device can retain spatiotemporal visual information and achieve parallel perception of multiple motion parameters such as speed, direction, and rotation, providing key hardware support for future intelligent bionic vision systems.

[0050] In summary, this invention provides a two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition. It realizes motion trajectory recognition under different conditions using a simple dual-ended optical sensor device, overcoming the energy consumption and redundancy and delay problems caused by the previous three-ended devices. It is expected to build a new type of motion trajectory to serve artificial vision systems with simple device structures.

Claims

1. A two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition, comprising: The layers are, in order, a substrate, an InSe nanolayer, and a gold electrode layer.

2. The two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition according to claim 1, characterized in that... The gold electrode layer is located at both ends of the InSe nanolayer, forming a double-ended gold electrode.

3. The two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition according to claim 2, characterized in that: The substrate is SiO2 / Si or PDMS.

4. The two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition according to claim 1, 2 or 3, characterized in that: The InSe nanolayer is two-dimensional γ-InSe.

5. The two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition according to claim 4, characterized in that: The SiO2 / Si is a Si substrate covered with a 300 nm SiO2 layer, and the InSe nanolayer has a thickness of 30–40 nm.

6. The method for fabricating the two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition as described in claim 1, comprising the following steps: 1) Fabrication of a gold electrode layer; a. Cut SiO2 / Si into squares and clean them; b. Spin-coating photoresist onto the SiO2 / Si substrate; c. Draw the required electrode pattern and import it into a maskless lithography machine for exposure and development; d. 0.03g of gold is deposited on the substrate by vapor deposition, the photoresist is washed off, and the substrate is dried to obtain a patterned gold electrode on the SiO2 / Si substrate; 2) Transfer the InSe nanolayer onto another SiO2 / Si substrate; 3) The gold electrode prepared in step 1) is attached to the top of the InSe nanolayer to prepare the upper gold electrode layer; 4) After removing any residual PVA adhesive, blow dry. 5) Anneal at 120 °C for 10 min in a vacuum environment.

7. The method for fabricating a two-dimensional indium selenide biomimetic visual light sensor with motion trajectory recognition according to claim 6, characterized in that: The InSe nanolayer described in step 2) is prepared by mechanical exfoliation.

8. The method for fabricating a two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition according to claim 7, characterized in that: Step 4) The gold electrode layer is prepared by spin-coating the gold electrode prepared in step 1) with an 8% PVA solution. After the PVA solution forms a film, the gold electrode is peeled off with the help of PDMS and attached to the InSe nanolayer to prepare the gold electrode layer.

9. The application of the two-dimensional indium selenide biomimetic optical sensor with motion trajectory recognition as described in claim 1 in the field of artificial vision.

10. The application according to claim 9, characterized in that: The artificial vision mentioned above is used to identify motion trajectories. The identification of motion trajectories is achieved by creating a current mapping image based on the changes in the It curve of the reverse peak of the photothermal phenomenon.

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