Photoelectric sensing element, photoelectric sensing array and preparation method

Abstract

The invention relates to a photoelectric sensing element, a photoelectric sensing array and a preparation method, the photoelectric sensing element comprises a substrate, a transistor module and a photoelectric detection module, the transistor module comprises a grid electrode, a first dielectric layer, an active layer, a first source electrode, a first drain electrode and a first passivation layer; the photoelectric detection module is sequentially provided with a second dielectric layer, a second source electrode, a second drain electrode and a second passivation layer from bottom to top; the first source electrode, the first drain electrode, the second drain electrode, the second source electrode and an external reading circuit are connected in series to form a loop; and a photosensitive induction layer of the photoelectric detection module is filled into a channel between the second source electrode and the second drain electrode. The transistor module and the photoelectric detection module are integrated on the substrate and are connected in series to form a complete loop, and the photosensitive sensing layer made of the two-dimensional transition metal chalcogenide is adopted, so that efficient capture, conversion and output of optical signals are realized, the sensitivity and response speed of optical signal detection are improved, and the structural stability of the device and the accuracy of signal transmission are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of photoelectric sensor technology, and more particularly to a photoelectric sensing element, a photoelectric sensing array, and a method for fabricating it. Background Technology

[0002] Optical sensor array technology serves as a core supporting technology in many fields such as image perception, optical inspection, and bionic vision. Its performance directly determines the perception accuracy, response speed, and environmental adaptability of related application systems, and it has been widely applied in key scenarios such as consumer electronics, industrial inspection, autonomous driving, and biomedicine. Currently, optical sensor array technology can be mainly divided into three categories: traditional image sensor technology, novel optoelectronic material-based sensor technology, and bionic sensor design technology. Although each type of technology has made certain progress, there are still many technical shortcomings that urgently need to be addressed in practical applications.

[0003] Traditional image sensors, based on charge-coupled devices (CCDs) and complementary metal-oxide-semiconductor (CMOS) sensors, utilize silicon-based semiconductor technology and capture and convert light signals through photodiode arrays, making them the most widely used optical sensing solution. However, these sensors have inherent limitations: Firstly, they employ a fixed sampling rate for signal acquisition, coupled with a serial architecture of "photosensing-analog-digital conversion-digital processing." This not only leads to frequent data transfer between the sensor and processor, resulting in processing delays of up to hundreds of milliseconds, but also causes significant power consumption due to the large amount of data movement, typically exceeding 100mW, making it difficult to meet the application requirements of portable, low-power devices. Secondly, their dynamic range is relatively fixed (approximately 60dB), making them prone to pixel saturation or noise interference under extreme lighting conditions such as direct sunlight, low illumination, or high contrast, severely affecting image quality. Even optimization using high dynamic range (HDR) technology cannot fundamentally solve this problem.

[0004] To overcome the limitations of traditional silicon-based sensors, the industry has gradually developed optical sensor technologies based on novel optoelectronic materials, mainly including sensors based on organic optoelectronic materials, perovskite materials, and low-dimensional materials (such as graphene and quantum dots). Among them, organic optoelectronic materials have the advantages of flexibility and large-area fabrication, making them suitable for flexible devices such as biomimetic retina; perovskite materials, due to their high light absorption coefficient, show great potential in the field of high-efficiency photoelectric conversion; and low-dimensional materials, with their ultrafast response speed and wide spectral sensitivity, have become an important direction for improving sensor response performance. However, this type of novel sensor technology is currently limited by material preparation and integration processes. In practical applications, it can usually only realize discrete devices or small passive arrays (such as 4×4 or 8×8 scale). The low integration problem directly leads to three core technical bottlenecks: First, the spatial resolution is limited (usually less than 100 PPI), which cannot meet the needs of high-precision imaging, precision detection and other scenarios. Second, there is a lack of effective isolation between adjacent pixels, which will produce serious charge diffusion and crosstalk when densely integrated into arrays. The crosstalk rate usually exceeds 15%, which significantly reduces image contrast and signal fidelity. Third, there is a serious impedance mismatch between the readout circuit and the sensing unit, which causes the sensor response time to be extended to the millisecond level, making it difficult to capture high-speed dynamic scenes with frame rates exceeding 100fps, thus limiting its application in dynamic imaging tasks such as high-speed target tracking and real-time gesture recognition.

[0005] While biomimetic sensor design technologies (such as event cameras and pulse output sensors) draw on the working mechanism of the biological retina to asynchronously output light intensity change events or directly generate pulse signals, making some progress in reducing data redundancy and improving dynamic responsiveness, their core sensing units still largely rely on traditional silicon-based materials or novel optoelectronic materials with low integration. The aforementioned deficiencies regarding response speed, integration, power consumption, and environmental adaptability have not been fundamentally resolved, making it difficult to meet the high-precision, real-time light sensing requirements in complex scenarios. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a photoelectric sensing element, a photoelectric sensing array, and a method for fabricating them.

[0007] The technical solution adopted by this application to solve its technical problem is as follows: a photoelectric sensing element, including a substrate, a transistor module, and a photoelectric detection module. Both the transistor module and the photoelectric detection module are disposed on the substrate. The transistor module includes, from bottom to top, a gate, a first dielectric layer, an active layer, a first source and a first drain, and a first passivation layer. The gate is disposed on the substrate, and the passivation layer covers the first source and the first drain and fills the channel between the first source and the first drain. The photoelectric detection module includes, from bottom to top, a second dielectric layer, a second source and a second drain, and a second passivation layer. The second dielectric layer is disposed on the substrate, and the second passivation layer covers the second source and the second drain. The first source, the first drain, the second drain, and the second source are connected in series with an external readout circuit to form a loop. The photoelectric detection module further includes a photosensitive layer, which fills at least the channel between the second source and the second drain. The photosensitive layer is made of a two-dimensional transition metal dichalcogenide compound.

[0008] More specifically, the second dielectric layer is formed by extending from the first dielectric layer and covering the photoelectric detection module area.

[0009] More specifically, the first dielectric layer includes a SiO2 layer near the substrate and a Si3N4 layer located on the SiO2 layer.

[0010] More specifically, the second passivation layer is formed by extending the first passivation layer to cover the photoelectric detection module area and etching it.

[0011] More specifically, the second drain is formed by extending the first drain to cover part of the photoelectric detection module area.

[0012] More specifically, the two-dimensional transition metal chalcogenide is selected from tungsten disulfide, tungsten diselenide, or molybdenum disulfide.

[0013] More specifically, the material of the active layer is selected from one of α-IGZO, IZTO, IZO, Ga2O3, and In2O3.

[0014] An optoelectronic sensing array includes the aforementioned optoelectronic sensing elements arranged in an array, a driving circuit for controlling a transistor module, and a reading circuit for reading the optoelectronic detection module.

[0015] A method for fabricating a photoelectric sensing element, the method comprising the following steps: S1. Provide a substrate; S2. A gate electrode layer is deposited on the substrate by DC sputtering, and a gate pattern is formed on the gate electrode layer by wet etching. S3. The first dielectric layer and the second dielectric layer are simultaneously formed on the gate and the substrate by PECVD. S4. An active layer is formed on the first dielectric layer using radio frequency magnetron sputtering. S5. Source and drain electrode layers are deposited on the active layer and the second dielectric layer by DC sputtering, and the first source, the first drain, the second source, and the second drain are formed on the source and drain electrode layers by wet etching. S6. A passivation layer is formed on the transistor module region and the photodetector module region by PECVD. The passivation layer covers the first source, the first drain, the second source and the second drain. The first passivation layer and the second passivation layer are formed on the passivation layer by wet etching, and the channel between the second source and the second drain is exposed. S7. Provide a temporary substrate; S8. A large-area monolayer photosensitive thin film is deposited on a temporary substrate using the CVD method; S9. Spin-coat polymethyl methacrylate onto the photosensitive film, and bake it after coating. S10. The photosensitive thin film is transferred onto the passivation layer using a wet transfer method and covers the channel between the second source and the second drain to form a photosensitive layer, thus obtaining a photoelectric sensing element.

[0016] More specifically, step S10 includes, S101. Peel the photosensitive film with polymethyl methacrylate from the temporary substrate; S102. Use deionized water to transfer the photosensitive film containing polymethyl methacrylate onto the passivation layer and cover the channel between the second source and the second drain. S103. Anneal at 80°C for 30 minutes, then at 120°C for 1 hour, and finally at 150°C for 1 hour to remove moisture.

[0017] S104. The entire assembly is immersed in hot acetone to dissolve polymethyl methacrylate, then rinsed with isopropanol to form a photosensitive layer, finally obtaining the photoelectric sensing element.

[0018] The beneficial effects of this application are as follows: by integrating a transistor module and a photodetector module on a substrate and connecting them in series to form a complete circuit, and using a two-dimensional transition metal chalcogenide photosensitive layer, efficient capture, conversion, and output of optical signals are achieved; relying on the wide spectral sensitivity and ultrafast carrier migration characteristics of the two-dimensional transition metal chalcogenide, the sensitivity and response speed of optical signal detection are improved; the integrated design of the transistor module and the photodetector module ensures the stability of the device structure and the accuracy of signal transmission; the product of this application has a faster response, lower power consumption, higher resolution, and also has the ability to temporarily store optical information and dynamically modulate it. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the photoelectric sensing element of the present invention; Figure 2 This is a schematic diagram of the process structure of the photoelectric sensing element fabrication method of the present invention; Figure 3 This is a flowchart of the method for preparing the photoelectric sensing element of the present invention; Figure 4 This is a flowchart of the process for forming the photosensitive layer of the photoelectric sensing element of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The direction of movement is also relative and is not limited to an absolute direction of movement. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] like Figure 1 This application provides a photoelectric sensing element, including a substrate, a transistor module, and a photoelectric detection module. Figure 1 The left side is the transistor module. Figure 1On the right is the photoelectric detection module. The transistor module and the photoelectric detection module are arranged side by side on the same surface of the substrate. The two are connected in series with the external reading circuit through the electrode lead-out structure to form a complete photoelectric detection circuit, realizing the capture, conversion and output of light signals. By integrating thin film transistors (TFTs) and single-layer two-dimensional transition metal chalcogenide photodetectors, an M×N active matrix optical sensor array is constructed to realize high-resolution static image sensing and dynamic motion prediction functions.

[0024] The substrate can be one of a glass substrate, a sapphire substrate, or a flexible polyimide (PI) film. As a support base, it must have good insulation, flatness, and compatibility with subsequent functional layers.

[0025] The transistor module includes, from bottom to top, a gate, a first dielectric layer, an active layer, a first source and a first drain, and a first passivation layer.

[0026] The gate is disposed on the substrate with a thickness of 200 nm. Molybdenum (Mo) can be selected as the electrode material. When the scene is transparent, the gate can be made of indium tin oxide (ITO). The gate is used to apply a control voltage to make the transistor module turn off or on.

[0027] The first dielectric layer is a gate insulating layer covering the gate and the exposed area of ​​the substrate. It adopts a SiO2 / Si3N4 double-layer stacked structure, wherein the SiO2 layer near the substrate has a thickness of 50nm, and the Si3N4 layer stacked on the SiO2 layer has a thickness of 250nm. This composite structure can take into account both insulation and interface compatibility.

[0028] The active layer is disposed on the side of the first dielectric layer away from the gate (i.e., the surface of the Si3N4 layer), corresponding to the region directly above the gate, and serves as the transistor's conductive channel. The preferred material is α-IGZO (amorphous indium gallium zinc oxide), but it can also be replaced with one of IZTO, IZO, Ga2O3, or In2O3.

[0029] The first source and the first drain are disposed on the active layer with a thickness of 200 nm. Molybdenum (Mo) can be selected as the electrode material. When the scene is transparent, the gate can be made of indium tin oxide (ITO). A channel is formed between the first source and the first drain, and the width-to-length ratio (W / L) of the channel is 105 μm / 5 μm.

[0030] The first passivation layer covers the first source, the first drain, and the channel between the first source and the first drain; the first passivation layer is made of SiO2 and has a thickness of 200nm, which plays a role in protecting the core structure of the transistor and stabilizing its performance.

[0031] The photodetector module and the transistor module are spaced apart by a distance ≥5μm to avoid crosstalk between electrodes. The photodetector module is provided with a second dielectric layer, a second source and a second drain, and a second passivation layer from bottom to top. The photodetector module also includes a photosensitive layer, which fills at least into the channel formed between the second source and the second drain.

[0032] The second dielectric layer is integrally extended from the first dielectric layer and covers the substrate area corresponding to the photoelectric detection module, serving as an insulating layer to prevent short circuits between the electrodes of the photoelectric detection module and the substrate. Its material and thickness are completely consistent with the first dielectric layer to ensure structural compatibility.

[0033] The second source and the second drain are disposed on the second dielectric layer, and a channel is formed between the second source and the second drain. The width of the channel is controlled between 10-50 μm. The second source, the second drain, the first source, and the first drain are etched from the same electrode layer. The second drain can be formed by integrally extending the first drain and covering part of the photoelectric detection module area.

[0034] The second passivation layer covers the second source and the second drain. Its material and thickness are the same as the first passivation layer. It is made of SiO2 and has a thickness of 200nm. The second passivation layer is formed by extending the first passivation layer to cover the photoelectric detection module area and etching it.

[0035] The photosensitive layer is the core component of the photodetector module. Its main purpose is to cover the channel region formed between the second source and the second drain. It is made of a two-dimensional transition metal chalcogenide, specifically one of tungsten disulfide (WS2), tungsten diselenide (WSe2), or molybdenum disulfide (MoS2), preferably a single layer of WS2. The inherent defects in the WS2 layer can serve as charge trap centers to realize the storage of optical information and dynamic modulation of photoelectric properties. The photosensitive layer is completely covered in the transistor module region and the photodetector module region by wet transfer and extends into the channel between the second source and the second drain.

[0036] Based on the aforementioned photoelectric sensing elements, several elements are selected and arranged in an array, and used in conjunction with a driving circuit for controlling the transistor module and a reading circuit for reading the photoelectric detection module to form a photoelectric sensing array. The first source, first drain, second drain, second source, and external reading circuit are connected in series to form a loop. The first source can be connected to the input terminal of the reading circuit, and the second source can be connected to the output terminal of the reading circuit. The first drain and second drain are designed as an integrated structure. The gate is separately led out and connected to an external control circuit, which is a bias circuit used to control the switching state of the transistor module.

[0037] Its working principle is as follows: When a light signal shines on the photosensitive layer, the two-dimensional transition metal chalcogenide absorbs photon energy, exciting and generating electron-hole pairs (photogenerated carriers). Due to inherent defects in the photosensitive layer, these defects act as charge trap centers, capturing and stably storing some of the photogenerated carriers, forming a "memory" effect of the light signal. The greater the intensity of the light signal and the longer the irradiation time, the more carriers are trapped, and the more significant this memory effect becomes. The trapped carriers change the carrier concentration of the photosensitive layer, leading to a continuous change in its conductivity characteristics (the light signal intensity is positively correlated with conductivity). This conductivity modulation is reversible and stable. After the light signal disappears, the trapped carriers can still remain in the trap center for a certain period of time, maintaining the conductivity state for the corresponding duration, realizing the temporary storage function of light information, and providing a basis for dynamic motion prediction and event-driven processing.

[0038] The transistor module acts as a switching element. By applying a bias voltage to the gate, the conduction state of the transistor module is controlled. When an effective bias voltage is applied to the gate, the transistor is turned on, enabling the photoelectric detection module to form a path with the external reading circuit. When no bias voltage is applied, the transistor is turned off, which can avoid crosstalk between adjacent photoelectric sensing elements and ensure the accuracy of signal reading.

[0039] After the transistor module is turned on, the external readout circuit can inversely deduce the corresponding light signal intensity and irradiation duration by measuring the change in conductivity of the photosensitive layer. Since the change in conductivity is directly related to the number of captured charge carriers, no additional analog-to-digital conversion step is required, and the detection results can be output quickly. Combined with the carrier migration characteristics of the photosensitive layer, the response time of the entire sensing unit is short, and high-sensitivity detection can be achieved.

[0040] This application achieves high-precision detection of optical signals and provides the ability to temporarily store and dynamically modulate optical information by coordinating the defect charge trapping function of the photosensitive layer with the switching control of the transistor module, thus providing hardware support for event-driven and motion prediction in neuromorphic visual processing.

[0041] like Figure 2 and Figure 3 This application also provides a method for fabricating a photoelectric sensing element, the steps of which are as follows: S1. Provide a substrate: preferably one of a single-crystal silicon wafer, a sapphire substrate, or a flexible polyimide (PI) film.

[0042] For applications in flexible electronics, a flexible PI film with a thickness of 50-200μm is selected, and its surface needs to be treated with plasma (processing power 300-500W, processing time 30-60s) to improve the adhesion to the subsequent gate. For applications in high-precision imaging, a single-crystal silicon wafer with a surface roughness Ra≤0.5nm is selected, and a SiO2 buffer layer with a thickness of 100-200nm is formed on its surface through thermal oxidation process to further reduce the charge interference of the substrate to the subsequent functional layer. Sapphire substrates can be used directly without additional treatment.

[0043] S2. Transistor gate fabrication: A gate electrode layer is deposited on the substrate using a DC sputtering process. Molybdenum (Mo) is the preferred electrode material, and the deposition thickness is controlled to 200 nm. After deposition, a wet etching process is used to form the gate pattern on the gate electrode layer. For transparent scenarios, indium tin oxide (ITO) can be used instead.

[0044] S3. Simultaneous fabrication of the first and second dielectric layers: A thin film is deposited over the entire gate and substrate using plasma-enhanced chemical vapor deposition (PECVD) to form a SiO2 / Si3N4 double-layer stacked dielectric layer, wherein the SiO2 layer near the substrate has a thickness of 50 nm, and the Si3N4 layer stacked on top of it has a thickness of 250 nm; the dielectric layer is divided into a first dielectric layer and a second dielectric layer according to the region, and the second dielectric layer of the photodetector is formed by integrally extending the first dielectric layer to cover the corresponding region, without the need for separate fabrication, thus simplifying the process.

[0045] S4. Preparation of active layer: An active layer is deposited on the Si3N4 surface of the first dielectric layer using a radio frequency (RF) magnetron co-sputtering method. The preferred material is α-IGZO (amorphous indium gallium zinc oxide), but it can also be replaced by one of IZTO, IZO, Ga2O3, or In2O3.

[0046] The target material with In / Ga / Zn / O = 1:1:1:4 was selected, the sputtering power was 100-150W, and the deposition thickness was 30nm. After deposition, the pattern was formed by oxalic acid wet etching and annealed in air at 350℃ for 30 minutes.

[0047] S5. Integrated fabrication of the first source / drain of the transistor module and the second source / drain of the photodetector module: A molybdenum (Mo) metal layer with a thickness of 200 nm is deposited on the surface of the active layer and the second dielectric layer using a DC sputtering process as the source / drain electrode layer; the first source and the first drain are simultaneously patterned using a wet etching process to form a channel between the two in the transistor region; the second source and the second drain are formed in the photodetector region, wherein the second drain is formed by integrally extending the first drain to cover part of the photodetector module region, and a channel is also formed between the second source and the second drain.

[0048] S6. Integrated fabrication of the first passivation layer of the transistor module and the second passivation layer of the photodetector module: Passivation layers are deposited over the entire area of ​​the transistor module and the photodetector module using PECVD process. The material selected is SiO2, with a thickness of 200nm, completely covering all electrodes. The entire passivation layer is patterned using a wet etching process. The portion retaining the transistor area is the first passivation layer, which fills the channel between the first source and the first drain. The portion retaining the photodetector area is the second passivation layer. At the same time, the channel between the second source and the second drain is etched to expose the channel for subsequent photosensitive layer laying. After etching, the transistor is annealed at 350°C in air for 30 minutes to stabilize transistor performance and improve interface quality.

[0049] S7. Provide a temporary substrate, which may be a sapphire substrate; S8. A large-area monolayer photosensitive thin film is deposited on a temporary substrate using the CVD method. In this application, the photosensitive thin film is deposited using WS2.

[0050] S9. Pretreatment of the photosensitive film: Spin-coat polymethyl methacrylate (PMMA, molecular weight 950k) onto the deposited photosensitive film using a two-stage spin-coating process. After each coating, bake at 180°C for 90 seconds to cure, forming a protective film for subsequent transfer.

[0051] S10. Transfer the photosensitive layer and complete the finished product preparation: The photosensitive film is transferred to the passivation layer by a wet transfer method, and the channel between the second source and the second drain exposed by etching the passivation layer is covered to form the photosensitive layer, and finally the photoelectric sensing element is obtained.

[0052] like Figure 4 The specific steps in step S10 shown include: S101. Peel the photosensitive film with PMMA from the temporary substrate; S102. Use deionized water to transfer the photosensitive film with PMMA onto the passivation layer, ensuring that it covers the channel region between the second source and the second drain exposed by etching, and forms electrical contact only with the exposed electrode region. S103. Anneal at 80°C for 30 minutes, 120°C for 1 hour, and 150°C for 1 hour in sequence to completely remove moisture from the film and interface. S104. Immerse the entire unit in 50°C hot acetone for 10 minutes to dissolve and remove the PMMA protective film. Then rinse it clean with isopropanol to form a photosensitive layer, and finally obtain a complete photoelectric sensing element.

[0053] The photoelectric sensing element, photoelectric sensing array, and fabrication method provided in this application construct a complete photoelectric detection circuit by arranging transistor modules and photoelectric detection modules in parallel on a substrate. The photosensitive layer of the photoelectric detection module is made of a two-dimensional transition metal chalcogenide compound, and the dielectric layer, passivation layer, and source / drain electrodes are all fabricated through integrated extension and etching, simplifying the process and improving compatibility. The photoelectric sensing array is formed by arranging this element array, and is equipped with driving circuits and readout circuits to realize its functions. Its fabrication is carried out by DC sputtering, PECVD, wet etching and other processes to complete the formation of each functional layer, and then the photosensitive thin film is laid by wet transfer. The final product has faster response, lower power consumption, higher resolution, and also has the ability to temporarily store optical information and dynamically modulate.

[0054] The application has yielded significant results, as detailed below: 1. Low power consumption design: By eliminating the dedicated storage capacitor in traditional pixels and adopting a direct pulse coding and event-driven circuit architecture, the pixel structure is simplified, reducing the power consumption of a single pixel to the microwatt level (<1μW / pixel). The overall system energy efficiency is more than 5 times higher than that of traditional CMOS sensors, significantly extending the battery life of edge devices.

[0055] 2. Breaking through the limitations of spatial resolution: By adopting an M×N active matrix array design and integrated fabrication process, large-scale component integration is achieved, and the spatial resolution far exceeds 100 PPI, fully meeting the needs of high-precision imaging, precision detection and other scenarios. 3. Suppressing charge diffusion and crosstalk: Through the spacing design between the transistor module and the photoelectric detection module, the insulation isolation of the SiO2 / Si3N4 double dielectric layer and the protection of the passivation layer, the interference between adjacent pixels is effectively blocked, the crosstalk rate is greatly reduced, and the image contrast and signal fidelity are significantly improved. 4. Optimized impedance matching and response speed: With the integrated design of transistor module and photoelectric detection module, the impedance mismatch problem between readout circuit and sensing unit is solved. Combined with the ultrafast carrier migration characteristics of two-dimensional transition metal chalcogenide, no additional analog-to-digital conversion step is required, the response time is greatly shortened, and high-speed dynamic scenes can be stably captured, which fully meets the real-time processing requirements of complex motion and dynamic imaging tasks such as gesture recognition and high-speed target tracking.

[0056] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A photoelectric sensing element, characterized in that, The device includes a substrate, a transistor module, and a photodetector module. Both the transistor module and the photodetector module are disposed on the substrate. The transistor module includes, from bottom to top, a gate, a first dielectric layer, an active layer, a first source and a first drain, and a first passivation layer. The gate is disposed on the substrate, and the passivation layer covers the first source and the first drain and fills the channel between them. The photodetector module includes, from bottom to top, a second dielectric layer, a second source and a second drain, and a second passivation layer. The second dielectric layer is disposed on the substrate, and the second passivation layer covers the second source and the second drain. The first source, the first drain, the second drain, and the second source are connected in series with an external readout circuit to form a loop. The photodetector module also includes a photosensitive layer that fills at least the channel between the second source and the second drain. The photosensitive layer is made of a two-dimensional transition metal dichalcogenide compound.

2. The photoelectric sensing element according to claim 1, characterized in that, The second dielectric layer is formed by extending from the first dielectric layer and covering the photoelectric detection module area.

3. The photoelectric sensing element according to claim 2, characterized in that, The first dielectric layer includes a SiO2 layer near the substrate and a Si3N4 layer on the SiO2 layer.

4. The photoelectric sensing element according to claim 1, characterized in that, The second passivation layer is formed by extending the first passivation layer to cover the photoelectric detection module area and etching it.

5. The photoelectric sensing element according to claim 1, characterized in that, The second drain is formed by extending the first drain and covering part of the photoelectric detection module area.

6. The photoelectric sensing element according to claim 1, characterized in that, The two-dimensional transition metal chalcogenide is selected from tungsten disulfide, tungsten diselenide, or molybdenum disulfide.

7. The photoelectric sensing element according to claim 1, characterized in that, The active layer is made of one of α-IGZO, IZTO, IZO, Ga2O3, or In2O3.

8. A photoelectric sensing array, characterized in that, It includes photoelectric sensing elements as described in any one of claims 1-7 arranged in an array, a driving circuit for controlling the transistor module, and a reading circuit for reading the photoelectric detection module.

9. A method for fabricating the photoelectric sensing element of claim 1, characterized in that, The preparation method comprises the following steps: S1. Provide a substrate; S2. A gate electrode layer is deposited on the substrate by DC sputtering, and a gate pattern is formed on the gate electrode layer by wet etching. S3. The first dielectric layer and the second dielectric layer are simultaneously formed on the gate and the substrate by PECVD. S4. An active layer is formed on the first dielectric layer using radio frequency magnetron sputtering. S5. Source and drain electrode layers are deposited on the active layer and the second dielectric layer by DC sputtering, and the first source, the first drain, the second source, and the second drain are formed on the source and drain electrode layers by wet etching. S6. A passivation layer is formed on the transistor module region and the photodetector module region by PECVD. The passivation layer covers the first source, the first drain, the second source and the second drain. The first passivation layer and the second passivation layer are formed on the passivation layer by wet etching, and the channel between the second source and the second drain is exposed. S7. Provide a temporary substrate; S8. A large-area monolayer photosensitive thin film is deposited on a temporary substrate using the CVD method; S9. Spin-coat polymethyl methacrylate onto the photosensitive film, and bake it after coating. S10. The photosensitive thin film is transferred onto the passivation layer using a wet transfer method and covers the channel between the second source and the second drain to form a photosensitive layer, thus obtaining a photoelectric sensing element.

10. The preparation method according to claim 9, characterized in that, Step S10 includes, S101. Peel the photosensitive film with polymethyl methacrylate from the temporary substrate; S102. Use deionized water to transfer the photosensitive film containing polymethyl methacrylate onto the passivation layer and cover the channel between the second source and the second drain. S103. Anneal at 80°C for 30 minutes, then anneal at 120°C for 1 hour, and finally anneal at 150°C for 1 hour to remove moisture. S104. The entire assembly is immersed in hot acetone to dissolve polymethyl methacrylate, then rinsed with isopropanol to form a photosensitive layer, finally obtaining the photoelectric sensing element.

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