Light absorption active layer, polarized electro-synaptic transistor and preparation method of polarized electro-synaptic transistor

Abstract

The invention discloses a light absorption active layer, a polarized electro-synaptic transistor and a manufacturing method of the polarized electro-synaptic transistor, and relates to the technical field of photoelectric devices. The polarized electro-synaptic transistor comprises a grid electrode; the dielectric layer is arranged on the top of the grid electrode; the light absorption active layer is arranged on the top of the dielectric layer; the modification layers are arranged on the two sides of the top of the light absorption active layer; the drain electrode is arranged at the top of one modification layer; and the source electrode is arranged at the top of the other modification layer. According to the invention, the light absorption active layer is prepared through the organic crystal, and anisotropic photo-induced electron capture is caused by anisotropic light absorption of the organic crystal, so that a polarization-dependent photo-induced grid voltage regulation effect is induced. The anisotropic amplification source-drain current realizes higher polarization sensitivity and higher dichroic ratio, so that the finally prepared phototransistor has the polarization sensitivity exceeding the intrinsic anisotropic ratio, and the dichroic ratio exceeding 1 * 103 is realized.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic device technology, and in particular to a light-absorbing active layer and a polarization photoelectric synaptic transistor and its fabrication method. Background Technology

[0002] In the field of modern optoelectronic devices, polarization detectors and photoelectric synaptic devices are two important research directions. Polarization detectors can sense the polarization information of light, while photoelectric synaptic devices can simulate the behavior of biological synapses to realize the perception, processing, and storage of light signals. Many organisms in nature, such as insects, have polarization-sensitive compound eye structures and nervous systems. The polarization vision system of insects far surpasses current artificial polarization-sensitive synaptic devices in terms of polarization sensitivity and power consumption. Therefore, biomimetic photoelectric synaptic devices that can simulate the polarization vision system of insects are expected to provide new ideas for the next generation of biomimetic polarization vision systems.

[0003] Currently, commercially available polarized synaptic devices often require complex optical path designs and large device sizes, significantly limiting their application scenarios. To address this issue, the proposed strategy is to utilize anisotropic semiconductors to fabricate polarization-sensitive photoelectric synaptic devices. Theoretically, this could integrate polarization sensing, storage, and computation to achieve a high-performance biomimetic polarization-based visual neural system. However, due to the relatively late start of polarization-sensitive photoelectric synaptic devices, they are still in the proof-of-concept stage. Current polarization photoelectric synaptic transistors suffer from low dichroic color ratios, high power consumption, and high operating voltages, limiting their development in practical applications. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is: how to prepare small molecule organic semiconductor crystal strips with specific regularity as light-absorbing active layers, and how to use such active layers to construct transistors that are sensitive to polarized light and have synaptic-like functions, thereby improving polarization sensitivity and solving the technical problem that the dichroism ratio is generally less than 10.

[0005] The above-mentioned technical problems are solved by the following technical solutions:

[0006] This invention proposes a light-absorbing active layer comprising small molecule organic semiconductor crystal strips.

[0007] In a preferred embodiment of the light-absorbing active layer of the present invention: a small molecule organic semiconductor crystal strip is disposed on the top of the dielectric layer; a modification layer is provided on both sides of the top of the small molecule organic semiconductor crystal strip; the small molecule organic semiconductor crystal strip has multiple channels, each channel of the small molecule organic semiconductor crystal strip is in contact with the modification layer on both sides of the top, and the small molecule organic semiconductor crystal strip is uniformly and non-overlappingly distributed along a direction perpendicular to one modification layer to another.

[0008] The present invention also proposes a method for preparing a light-absorbing active layer, which includes preparing a solution, dropping solution droplets, and applying solution droplets by scraping.

[0009] In a preferred embodiment of the method for preparing the light-absorbing active layer of the present invention: a solution is prepared by weighing organic semiconductor powder and dissolving it in an organic solvent;

[0010] The solution is dropped evenly and without overlap onto one side of the dielectric layer.

[0011] Apply the solution droplets by scraping them onto the other side of the dielectric layer using a scraper at a uniform speed.

[0012] The present invention also proposes a polarization photoelectric synaptic transistor, which includes a gate, a dielectric layer, a light-absorbing active layer, a modification layer, a drain, and a source.

[0013] In a preferred embodiment of the polarization photoelectric synaptic transistor of the present invention: it includes a gate;

[0014] A dielectric layer is disposed on top of the gate; the light-absorbing active layer is disposed on top of the dielectric layer and has crystal anisotropy;

[0015] A modification layer is disposed on top of the light-absorbing active layer, and two modification layers are provided with a gap between them;

[0016] A drain electrode is disposed on top of one of the aforementioned decorative layers; and,

[0017] The source is located on top of another of the aforementioned decorative layers.

[0018] In a preferred embodiment of the polarization photoelectric synaptic transistor of the present invention, the gate is a conductive material layer.

[0019] In a preferred embodiment of the polarization photoelectric synaptic transistor of the present invention: the dielectric layer is a high dielectric constant insulating material layer with hydroxyl, carboxyl or amino functional groups on its surface.

[0020] In a preferred embodiment of the polarization photoelectric synaptic transistor of the present invention: the light-absorbing active layer comprises multiple spaced-apart strips of the small molecule organic semiconductor crystal.

[0021] In a preferred embodiment of the polarization photoelectric synaptic transistor of the present invention: one of the modification layers is disposed on one side of the top of the light-absorbing active layer, and the other modification layer is disposed on the other side of the top of the light-absorbing active layer.

[0022] In a preferred embodiment of the polarization photoelectric synaptic transistor of the present invention: the length and width of the drain and the modification layer at its bottom are equal;

[0023] The source electrode and the modification layer at its bottom have the same length and width.

[0024] In a preferred embodiment of the polarization photoelectric synaptic transistor of the present invention: the modification layer is a high work function p-type semiconductor material layer; the drain and the source are high conductivity material layers.

[0025] The present invention also proposes a method for fabricating a polarization photoelectric synaptic transistor, which includes fabricating a dielectric layer, fabricating a light-absorbing active layer, fabricating a modification layer and an electrode layer.

[0026] In a preferred embodiment of the method for fabricating the polarization photoelectric synaptic transistor of the present invention: a dielectric layer is prepared by depositing a high dielectric constant insulating material containing hydroxyl, carboxyl or amino functional groups on the surface of the gate as the dielectric layer;

[0027] To prepare a light-absorbing active layer, uniform and non-overlapping small molecule organic semiconductor solution droplets are dropped onto one side of the cleaned dielectric layer surface, and the small molecule organic semiconductor solution droplets are scraped onto the other side of the dielectric layer surface to form an organic small molecule semiconductor single crystal as a light-absorbing active layer.

[0028] A modification layer and an electrode layer are prepared by evaporating a high work function p-type semiconductor material layer as a modification layer and a high conductivity material layer as an electrode layer on the surface of the light-absorbing active layer using a metal mask.

[0029] The beneficial effects of this invention are as follows: This invention prepares a light-absorbing active layer using organic crystals. By utilizing the anisotropic light absorption of the organic crystals, anisotropic photogenerated electron trapping is achieved, thereby inducing a polarization-dependent photoinduced gate voltage modulation effect. The anisotropic amplification of the source leakage current results in higher polarization sensitivity and a higher dichroic ratio, enabling the final phototransistor to exhibit polarization sensitivity exceeding 1000 times that of intrinsic anisotropy, and a polarization sensitivity exceeding 1×10⁻⁶. 3 Extremely high dihedral ratio. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0031] Figure 1 A schematic flowchart of the fabrication method of a polarization photoelectric synaptic transistor is shown;

[0032] Figure 2 It shows Figure 1 Orthogonal polarized microscope images of small molecule organic semiconductor crystal strips prepared by scraping;

[0033] Figure 3 An atomic force microscope image of a small molecule organic semiconductor crystal array is shown.

[0034] Figure 4 A scanning electron microscope image of a small molecule organic semiconductor crystal array is shown.

[0035] Figure 5 The transmission electron microscope image of the small molecule organic semiconductor crystal array and its selected area diffraction pattern are shown.

[0036] Figure 6 A high-resolution atomic force microscope image of a small molecule organic semiconductor crystal array is shown.

[0037] Figure 7 A schematic diagram of the structure of a polarization photoelectric synaptic transistor is shown;

[0038] Figure 8 A schematic diagram of the polarization photoelectric synaptic transistor is shown.

[0039] Figure 9 The transfer characteristic curves of the polarization phototransistor at 0° (parallel to the channel direction) and 90° (perpendicular to the channel direction) are shown.

[0040] Figure 10 The polarization angle-dependent current of the polarization photosynthetic transistor at a fixed gate voltage (0.5 V) is shown;

[0041] Figure 11 The graph shows the polarization angle-dependent transfer characteristics of the polarization photoelectric synaptic transistor under different light intensities.

[0042] Figure 12 The contour plot of polarization-dependent source-drain current as a function of gate voltage for a polarized optical detector is shown.

[0043] Figure 13 The dichroic color ratio distribution of an 8×8 polarized photosynaptic transistor array is shown.

[0044] Figure 14 A schematic diagram of the neuronal characteristics of a polarization photoelectric synaptic transistor is shown.

[0045] Figure 15 The polarization angle of the polarized photosynaptic transistor depends on the excitatory postsynaptic current.

[0046] Figure 16 The curve showing the relationship between the polarization angle-dependent peak current and the incident light intensity of the polarized photoelectric synaptic transistor is presented.

[0047] Figure 17The dichroic color ratio and polarization angle-dependent weighting values ​​of the polarized photosynthetic transistor under different pulse widths are shown.

[0048] Figure 18 A schematic diagram of biomimetic polarization information exchange based on a polarization photoelectric synaptic transistor array is shown.

[0049] Figure 19 This demonstrates information exchange (in Morse code form) using polarized light based on a polarized photoelectric synaptic transistor array, with dichroic color ratio corresponding to saturation information;

[0050] Figure 20 This demonstrates information exchange (in Morse code form) using unpolarized light based on a polarized photoelectric synaptic transistor array, with dichroic color ratio corresponding to saturation information;

[0051] Figure 21 (a) shows a schematic diagram of a biomimetic polarization vision neural network, and (b) shows a normal color vision image and a polarization vision image;

[0052] Figure 22 (a) to (b) show the polarization angle-dependent multipulse excitatory postsynaptic currents of a polarized photoelectric synaptic transistor at different pulse numbers;

[0053] Figure 23 (a) to (b) show the square root values ​​of the polarization angle-dependent weights of the polarization photosynaptic transistor at different pulse numbers;

[0054] Figure 24 The image shows polarization image enhancement based on a polarization photoelectric synaptic transistor array. Detailed Implementation

[0055] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0056] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0057] Example 1, referring to Figure 1-7This embodiment provides a light-absorbing active layer, including a small molecule organic semiconductor crystal strip 301 disposed on top of the dielectric layer 200; the small molecule organic semiconductor crystal strip 301 is a C8-BTBT single crystal microstrip with a thickness of 10-20 nanometers. The full chemical name of C8-BTBT is 2,7-dioctyl[1]benzothiophene[3,2-b][1]benzothiophene, with [1]benzothiophene[3,2-b][1]benzothiophene as the core structure, and octyl C8 chains connected at positions 2 and 7, which have good air stability and high charge mobility. The dielectric layer 200 can be a hafnium oxide layer with a thickness of about 10-30 nanometers, and the dielectric layer 200 is pre-deposited on the gate of the silicon wafer substrate. The small molecule organic semiconductor crystal strip 301 is distributed in the same direction.

[0058] The top two sides of the small molecule organic semiconductor crystal strip 301 are provided with modification layers 400. The modification layer 400 can be a molybdenum oxide layer with a thickness of about 1-2 nanometers, or an organic modification layer such as F4-TCNQ. The two modification layers 400 are respectively in contact with the two ends of the small molecule organic semiconductor crystal strip 301 to improve the interface characteristics and promote charge injection and collection. The surface of the modification layer 400 is used to deposit electrodes. The electrodes can be metal electrodes such as gold, silver, copper, etc., or oxide electrodes such as ITO, FTO, etc., to form a complete source and drain electrode.

[0059] Multiple small-molecule organic semiconductor crystal strips 301 are present, each in contact with the top two modification layers 400. The small-molecule organic semiconductor crystal strips 301 are uniformly distributed and do not overlap along a direction perpendicular to one modification layer 400 to another. These multiple small-molecule organic semiconductor crystal strips 301 are distributed on the surface of the dielectric layer 200 in a substantially parallel, uniformly spaced manner without physical overlap, thus forming an ordered microstrip array. This array is used for high-sensitivity detection of polarized light by the light-absorbing active layer, which is beneficial for fabricating transistor array devices with uniform performance.

[0060] Example 2, refer to Figure 1-7 This embodiment provides a method for preparing a light-absorbing active layer, including preparing a solution by weighing organic semiconductor powder and dissolving it in an organic solvent.

[0061] Specifically, to prepare a solution, weigh out an organic semiconductor powder and dissolve it in an organic solvent; the organic semiconductor powder can be C8-BTBT powder, weigh out 10 mg, and the organic solvent can be toluene. After thoroughly stirring and dissolving the C8-BTBT powder together, a 10 mg / ml solution is prepared.

[0062] The dielectric layer can be a high-dielectric-constant insulating layer, 10-30 nanometers thick, composed of hafnium oxide or aluminum oxide, etc. The dielectric layer is located on the gate surface, which can be a silicon wafer, indium tin oxide, or a metallic material. Before the solution is dropped, the gate and dielectric layer are cleaned with ozone. This removes contaminants and impurities from the dielectric layer surface, while also improving surface energy and wettability, facilitating the uniform spreading of the C8-BTBT solution and the formation of high-quality single-crystal microstrips.

[0063] The solution is dropped evenly and non-overlappingly onto one side of the dielectric layer; the dielectric layer is the part that carries the light-absorbing active layer; "even and non-overlapping drops" are to form multiple liquid lines of controllable width and thickness as the scraper moves.

[0064] A doctor blade is used to uniformly spread a droplet of solution from one side of the dielectric layer to the other. The cleaned dielectric layer with the gate is placed on a layer-stepping electric displacement stage, and the doctor blade is controlled to spread the solution at a speed of 200-300 μm / s. During the spreading process, the solution spreads under the shear force of the doctor blade, the solvent gradually evaporates, and the organic semiconductor material self-assembles and crystallizes on the substrate surface, thereby forming multiple C8-BTBT microstrips as small molecule organic semiconductor crystal strips 301.

[0065] Example 3, referring to Figure 1-17 This embodiment provides a polarization photoelectric synaptic transistor, including a gate 100, a dielectric layer 200, a light-absorbing active layer 300, a modification layer 400, a drain 500, and a source 600.

[0066] Specifically, the gate 100 is located at the bottom layer and can be a metal electrode such as gold, silver, or copper, or an oxide electrode such as indium tin oxide (ITO) or tin oxide (FTO), or other conductive electrodes such as conductive polymers PEDOT:PSS or graphite. At the same time, the gate 100 also serves as the supporting substrate for the entire device.

[0067] The dielectric layer 200 is disposed on top of the gate 100 and serves to isolate the gate from the semiconductor layer and couple the gate electric field. It is a high dielectric constant material layer after 10-30 nanometers. It can be hafnium oxide or aluminum oxide, or an organic polymer layer such as PVP, PVA, or a composite layer structure of oxide layer and organic polymer layer. It is used to reduce the operating voltage of the device and enhance the controllability of the gate 100.

[0068] The light-absorbing active layer 300, disposed on top of the dielectric layer 200, is the core semiconductor layer that realizes photoelectric conversion and polarization sensitivity.

[0069] Modification layer 400, disposed on both sides of the top of light-absorbing active layer 300, is a 1-2 nanometer thick high work function p-type semiconductor material, which can be a molybdenum oxide layer or a 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4-TCNQ layer) used to improve the interface characteristics between the light-absorbing active layer and the subsequent metal electrode, and promote the effective injection and collection of charge.

[0070] The drain 500 is disposed on top of a decorative layer 400 as one of the current output terminals; the source 600 is disposed on top of another decorative layer 400 as one of the current input terminals.

[0071] Specifically, the drain 500 and source 600 are silver or gold electrodes with a thickness between 30 and 60 nanometers. To ensure good film quality and close contact with the underlying modification layer 400, the thermal evaporation rate during fabrication is preferably controlled to be less than [value missing]. Because the hydroxyl, carboxyl, or amino groups on the surface of the insulating layer have a strong electron-trapping ability, the semiconductor single crystal / insulating layer interface is equivalent to a floating gate, which additionally modulates and amplifies the electrical signal under illumination, enhancing polarization sensitivity.

[0072] Specifically, the channel length between the drain 500 and the source 600 is 15-25 micrometers, and the width is 150-200 micrometers.

[0073] Figure 2-6 The crystallinity and anisotropy of organic small molecule single crystals prepared by blade coating are shown. Based on the characterization data of the crystals, it is demonstrated that organic small molecule single crystals prepared by blade coating have good crystallinity and excellent anisotropy, making them suitable for the preparation of polarization-sensitive photoelectric synaptic transistors.

[0074] Figure 8 A schematic diagram illustrating the electron-trapping mechanism of a polarization phototransistor is shown. Water and oxygen adsorbed at the silicon oxide interface undergo an electrochemical reaction under a positive gate voltage to form hydroxyl groups, which possess a strong electron-trapping capability.

[0075] Figure 9The scanned transfer characteristic curves of the polarization phototransistor at 0° and 90° polarization states are shown. The photoelectric characteristics of this polarization phototransistor were measured in a vacuum chamber at room temperature using a Keithley 4200-SCS semiconductor parameter analyzer. In the experiment, a 365nm ultraviolet LED was used as the light source. The UV lamp was connected to the output alligator clip of the oscilloscope via a simple circuit board. A rotatable ultraviolet polarizer, Thorlabs LPUV100-MP2, was fixed between the chamber and the UV lamp for polarization testing. The transfer characteristic curve of the device was scanned simultaneously with the switching on of the light. The source-drain current alternated with the polarization angle of the light every 90°, with the highest source-drain current at polarization angles of 0°, 180°, 360°, and 540°, and the lowest source-drain current at 90°, 270°, 450°, and 630°. These correspond to the polarization direction of the light being parallel to and perpendicular to the a-axis of the C8-BTBT crystal, respectively.

[0076] When the source-drain current in the vertically polarized state is in the transistor's off state (approximately 0.5V), the source-drain current in the parallel-polarized state has already risen to the transistor's on state. At this point, the maximum dichroic color ratio greater than 2 × 10⁻⁶ can be obtained. 3 This value amplifies the intrinsic anisotropic absorption ratio of the material (approximately 1.87) by more than 1000 times. Figure 9-10 This is because the anisotropic light absorption of the transistor causes a difference in the number of electrons captured. The captured electrons are equivalent to an additional negative gate voltage, which causes the threshold voltage of the transistor to shift. Moreover, the amount of shift is different in different polarization states, which also causes the gate voltage dependence of the device's polarization sensitivity.

[0077] Figure 11 This shows that, in addition to polarization angle dependence, incident light intensity can also cause a shift in the threshold voltage.

[0078] Figure 12 The stability of the electron capture and decapture process of the polarized photoelectric synaptic transistor is shown. As the polarization angle switches between 0° and 360°, the threshold voltage of the device shows a cosine function trend.

[0079] Figure 13 The diagram shows the DR value distribution of the polarization photosynaptic transistor array. A total of 64 transistor devices in an 8×8 array were tested, and all devices exhibited values ​​exceeding 1×10⁻⁶. 3 The above dichroic ratio demonstrates the device's excellent performance stability.

[0080] Figure 14A schematic diagram of a biomimetic synapse based on a polarized phototransistor is shown. When stimulated by external factors such as light, photogenerated electrons are generated within the channel of the polarized phototransistor device. These electrons are transported to the semiconductor / insulator interface and ultimately captured by interface defects. This process is similar to the release of synaptic neurotransmitters, which are then transported to and bind to receptors at the postsynapse. The captured electrons generate a local longitudinal electric field at the interface, attracting holes to form a conductive channel, thereby changing the device from an off state to an on state, similar to the activation of a postsynapse and the transmission of information.

[0081] Figure 15 The diagram shows that a polarized photoelectric synaptic transistor can sense polarized light pulse signals and convert them into electrical signals—excitatory postsynaptic currents.

[0082] Figure 16 The polarization phototransistor exhibits light intensity-dependent adaptive characteristics.

[0083] Figure 17 The results show that the dichroic color ratio and synaptic weight value of the polarized photoelectric synaptic transistor exhibit obvious pulse width dependence characteristics. By changing the pulse width, the dichroic color ratio and synaptic weight value of the device can be dynamically adjusted.

[0084] In particular, this embodiment also provides a strategy for implementing biomimetic polarized light communication, including the following steps:

[0085] The aforementioned polarization photoelectric synaptic transistor array is left stationary;

[0086] Each polarization photosynaptic transistor is considered as a separate "eye";

[0087] Projecting polarized light pulse signals onto a device array;

[0088] By using a polarization-sensitive photoelectric synaptic transistor array to sense polarized light pulse signals and translate them into electrical pulse signals, and by using polarization-dependent postsynaptic currents to transmit polarization information, the polarization angle information is mapped to color information, and the dichroism ratio information is mapped to contrast information. This biomimetic polarization information communication system can realize the transmission of information about polarization patterns in biomimetic butterfly wings.

[0089] This strategy is inspired by the behavior of butterflies using iridescent light on their wings to communicate with polarized light. When butterfly polarization-sensitive neurons receive polarized light information at different polarization angles, their activity changes, and they output polarization-angle-dependent electrical pulses, which are then translated into pulse frequency information. For non-polarization-sensitive neurons, different polarization angles do not alter cell activity, and the electrical pulses they output do not exhibit polarization-angle dependence. Polarization-sensitive phototransistor arrays can synchronously sense simple polarization image information, functioning similarly to the compound eye structure of a butterfly. When light pulses carrying only polarization information are input to the device, the photoresponse of subsequent neurons differs significantly from that under non-polarized light stimulation, allowing polarization information to be extracted through the output pulse pattern. Figure 18 By analyzing Morse code, output modes with different polarization information can be decoded into the symbols "L", "O", "V", and "E", respectively, while light stimuli without polarization information trigger indistinguishable output modes. After converting the encoded modes and dichroic ratios into color and color saturation, it becomes clear that the derived images containing polarization information have more vivid colors. Figure 18 This is a schematic diagram of biomimetic polarization information exchange based on a polarization photoelectric synaptic transistor array. Figure 19 It is based on a polarized photoelectric synaptic transistor array that uses polarized light to exchange information in the form of Morse code, with dichroism corresponding to saturation information. Figure 20 It is based on polarized photoelectric synaptic transistor arrays that use unpolarized light to communicate information, using Morse code, and the two-dimensional color ratio corresponds to saturation information.

[0090] In addition, this embodiment also provides a strategy for implementing biomimetic polarization image enhancement, including the following steps:

[0091] Construct a neural network based on polarized light synaptic transistors;

[0092] Using a polarization-sensitive synaptic transistor array to identify specific polarization targets in a polarization image;

[0093] By utilizing the pulse accumulation characteristic of polarized light synaptic transistors to enhance the dichroic ratio, and by increasing the number of training pulses, the contrast and dichroic ratio of polarized images are improved, thus simulating the polarized target recognition behavior of biomimetic butterflies.

[0094] According to one aspect of the present invention, the phototransistor prepared by the method of the present invention utilizes the anisotropic light absorption of organic crystals to induce anisotropic photogenerated electron trapping, thereby generating a polarization-dependent photoinduced gate voltage modulation effect. This effect can anisotropically amplify the source-drain current, achieving high polarization sensitivity and a high dichroic ratio.

[0095] By controlling various parameters and experimental details during the fabrication process, the final phototransistor can exhibit polarization sensitivity exceeding 1000 times its intrinsic anisotropy and an extremely high dichroic ratio exceeding 1×10³, which is two orders of magnitude higher than previously reported polarized light detectors and even reaches the extinction level of commercial polarizers, greater than 10. 3 .

[0096] This strategy is inspired by the target recognition behavior of butterflies using polarized light reflected from their leaves. The degree of polarization of the polarized light reflected from the leaf surface is closely related to its surface characteristics, such as roughness, color, and species. Figure 21 As shown, assuming smooth leaves reflect 0° polarized light, matte leaves and flowers reflect 90° polarized light and unpolarized light, respectively. The butterfly's polarization neural network, by distinguishing the polarized light reflected from different objects within its field of view and enhancing target contrast, can help it identify target leaves in complex backgrounds to optimize observation. Figure 22 This invention utilizes polarization-sensitive photoelectric synaptic transistors to construct an artificial neural network, simulating the target recognition behavior of butterflies searching for egg-laying sites. According to Hebb's law, continuous repetitive stimulation from preneurons to postneurons can improve synaptic transmission efficiency and enhance memory levels. This study investigated pulse-number-dependent synaptic plasticity by increasing the number of polarized light pulses from 1 to 200. The results showed that... Figure 23 In the 0° polarization state, the synaptic weight significantly increases with pulse repetition and exhibits a complete evolution process from STP to LTP; while in the 90° polarization state, no synaptic facilitation effect was observed regardless of the increase in the number of pulses.

[0097] In grayscale images, clustered leaves exhibit overlapping reflectance spectra, rendering traditional chromaticity discrimination methods ineffective. To achieve polarization image enhancement, we correlate the square root of polarization-dependent synaptic weights with grayscale values ​​in the image, ranging from 0 to 255. Figure 23 The relationship between the square root of synaptic weights and the number of pulses is shown in the 0° and 90° polarization states, revealing that the DR of the multi-pulse photoresponse between the 0° and 90° states is approximately 1.1 × 10³. Background leaves are assigned the square root of synaptic weights at a 90° polarization angle, while target leaves are assigned the square root of synaptic weights at a 0° polarization angle. After identifying the polarization angles of the reflections from all leaves, the contrast of the target leaves increases as the training epochs increase from 0 to 200. Figure 24 The high contrast features of the target leaf highlight the enormous potential of neuromorphic polarization vision in multidimensional optical information imaging applications, including polarization imaging, environmental monitoring, and bionic electronics.

[0098] Example 4, see reference Figure 1-7This embodiment provides a method for fabricating a polarization photoelectric synaptic transistor, including fabricating a dielectric layer, a light-absorbing active layer, a modification layer, and an electrode layer.

[0099] A dielectric layer is prepared by forming a high-quality dielectric insulating layer on the substrate of the gate. A layer of hafnium oxide is deposited on the surface of the gate of the n-doped silicon wafer as a dielectric layer. The n-doped silicon wafer is selected as the global bottom gate 100 of the device. It is ultrasonically cleaned in acetone, ultrapure water and ethanol in sequence to remove surface organic matter and particulate contaminants. Then it is dried with high-purity nitrogen. After cleaning, a layer of hafnium oxide with a thickness of about 10-30 nanometers is precisely grown on the clean surface of the n-doped silicon wafer using atomic layer deposition technology as the dielectric layer 200 of the device.

[0100] A light-absorbing active layer is prepared by forming an organic semiconductor layer with polarization-sensitive characteristics on a dielectric layer. Uniform and non-overlapping droplets of a small-molecule organic semiconductor solution are dropped onto one side of the cleaned dielectric layer surface, and then the droplets are scraped onto the other side of the dielectric layer surface to form a small-molecule organic semiconductor single crystal as the light-absorbing active layer. The small-molecule organic semiconductor solution is a 5-10 mg / ml toluene solution of C8-BTBT. The dielectric layer and gate to be coated are cleaned with ozone to further purify the surface and improve its wettability. Then, the cleaned substrate is placed on a stepper motor displacement platform, and the prepared C8-BTBT solution is uniformly dropped onto one end of the dielectric layer. Using a scraper at a constant scraping speed of 200-300 μm / s, the C8-BTBT solution is uniformly spread on the dielectric layer surface. As the solvent evaporates, the C8-BTBT molecules self-assemble and crystallize to form a single-crystal microstrip array with high orientation and excellent crystallinity, which constitutes the light-absorbing active layer 300 of this invention.

[0101] To prepare the modification layer and electrode layer, a molybdenum oxide modification layer and a silver electrode are deposited on the surface of the light-absorbing active layer using a metal mask. First, the source and drain patterned regions are defined using a metal mask. In these regions, a molybdenum oxide layer with a thickness of approximately 1-2 nm is grown on the C8-BTBT surface as a modification layer 400 to improve charge injection and collection efficiency and protect the organic semiconductor layer. Next, under the same vacuum environment, a silver layer with a thickness of 30-60 nm is deposited on top of the molybdenum oxide using the same metal mask to form the source 600 and drain 500 of the device. To ensure the quality of the silver electrode, its deposition rate is preferably controlled to be less than [value missing]. Metal masks ensure the accurate positioning of source and drain electrodes and define the channel length and width of the device.

[0102] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A light-absorbing active layer (300), characterized in that: include, Small molecule organic semiconductor crystal strips (301) are disposed on top of the dielectric layer (200); The small molecule organic semiconductor crystal strip (301) has a modification layer (400) on both sides of its top; The small molecule organic semiconductor crystal strip (301) has multiple channels, and each of the small molecule organic semiconductor crystal strips (301) is in contact with the top two sides of the modification layer (400). The small molecule organic semiconductor crystal strips (301) are uniformly and non-overlappingly distributed along a direction perpendicular to one of the modification layers (400) to another modification layer (400).

2. A method for preparing a light-absorbing active layer (300), characterized in that: Suitable for preparing the light-absorbing active layer as described in claim 1, the preparation method includes, To prepare a solution, weigh out the organic semiconductor powder and dissolve it in an organic solvent. The solution is dropped evenly and without overlap onto one side of the dielectric layer. Apply the solution droplets by scraping them onto the other side of the dielectric layer using a scraper at a uniform speed.

3. A polarization photoelectric synaptic transistor, characterized in that: Including the light-absorbing active layer (300) as described in claim 1, and further comprising, Gate (100); A dielectric layer (200) is disposed on top of the gate (100); a light-absorbing active layer (300) is disposed on top of the dielectric layer (200) and has crystal anisotropy; A modification layer (400) is disposed on top of the light-absorbing active layer (300), and two modification layers (400) are disposed with a gap between them; A drain (500) is disposed on top of one of the decorative layers (400); and, The source (600) is disposed on top of another of the modified layers (400).

4. The polarization photoelectric synaptic transistor according to claim 3, characterized in that: The gate (100) is a conductive material layer.

5. The polarization photoelectric synaptic transistor according to claim 3, characterized in that: The dielectric layer (200) is an insulating material layer with a high dielectric constant whose surface contains hydroxyl, carboxyl, or amino functional groups.

6. The polarization photosynthetic transistor according to claim 3, characterized in that: The light-absorbing active layer (300) includes multiple spaced small molecule organic semiconductor crystal strips (301).

7. The polarization photoelectric synaptic transistor according to claim 3, characterized in that: One of the modification layers (400) is disposed on one side of the top of the light-absorbing active layer (300), and the other modification layer (400) is disposed on the other side of the top of the light-absorbing active layer (300).

8. The polarization photosynaptic transistor according to claim 3, characterized in that: The length and width of the drain (500) and the decorative layer (400) at its bottom are equal; The source electrode (600) and the modification layer (400) at its bottom have the same length and width.

9. The polarization photosynthetic transistor according to claim 3, characterized in that: The modification layer (400) is a high work function p-type semiconductor material layer; the drain (500) and the source (600) are high conductivity material layers.

10. A method for fabricating a polarization photoelectric synaptic transistor, characterized in that: Suitable for fabricating polarized photoelectric synaptic transistors as described in any one of claims 3 to 9, the fabrication method comprising, To prepare a dielectric layer, a high dielectric constant insulating material containing hydroxyl, carboxyl, or amino functional groups is deposited on the surface of the gate as a dielectric layer. To prepare a light-absorbing active layer, uniform and non-overlapping small molecule organic semiconductor solution droplets are dropped onto one side of the cleaned dielectric layer surface, and the small molecule organic semiconductor solution droplets are scraped onto the other side of the dielectric layer surface to form an organic small molecule semiconductor single crystal as a light-absorbing active layer. A modification layer and an electrode layer are prepared by evaporating a high work function p-type semiconductor material layer as a modification layer and a high conductivity material layer as an electrode layer on the surface of the light-absorbing active layer using a metal mask.

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