Plasmonic two-dimensional material photoresistor variable device, array and in-sensing color image encryption method

Abstract

The present invention discloses a plasmon type two-dimensional material photoresistance variable device, array and in-sensor color image encryption method. The present invention introduces the surface plasmon effect of precious metals into a photoresistance variable device, constructs a plasmon type photoresistance variable device, and studies an in-sensor color image encryption method based on a surface plasmon type photoresistance variable device array. While realizing color image perception and storage through the non-volatile storage characteristics of the device, the reconfigurable physical unclonable function key is collected through the intrinsic random characteristics of the high-resistance state resistance value of the resistive variable device, thereby realizing high-performance in-situ encryption of in-sensor color images at the hardware level, which can not only reduce data transmission, improve efficiency, and reduce power consumption, but also increase key randomness and improve security.

Description

Technical Field

[0001] The present invention belongs to the field of microelectronics, optoelectronics and visual information encryption technology, and in particular relates to a plasmonic two-dimensional material photoresistor variable device, an array and a color image encryption method. Background Art

[0002] With the widespread popularity and rapid growth of applications such as face recognition, face payment, and video conferencing, high-reliability encryption technology is urgently needed to improve the security of image and video information during network transmission. At present, algorithm-based image encryption technology is extremely vulnerable to machine learning attacks, while traditional hardware-level image encryption is extremely vulnerable to attacks during network transmission due to the relative separation of image acquisition and information encryption. By integrating imaging and encryption into a single device, a new type of hardware-level in-sense image encryption can be achieved. Among the many optoelectronic devices reported for in-sense image encryption, the use of physically unclonable function (PUF) keys to complete the in-situ encryption of the collected image is beneficial to protect the image information from physical attacks. Photoresistance variable devices have great advantages in generating reconfigurable dynamic PUFs due to the high randomness of their own operating voltage and high and low resistance values. Therefore, studying photoresistance variable devices is helpful to improve the performance of in-sense image encryption.

[0003] At present, the working mechanism of photoresistance variable devices is mostly based on the mutual coupling between photogenerated carriers and conductive filaments of photosensitive semiconductor materials such as perovskites, two-dimensional materials and metal oxides, but the photogenerated carriers must migrate between the intermediate dielectric layers before interacting with the conductive filaments. Due to the surface plasmon effect, precious metals such as gold (Au) and silver (Ag) have strong light-matter interaction and light control characteristics. At the same time, Au and Ag can be used as electrode materials for photoresistance variable devices, and the hot electrons generated by the plasmon effect of Au and Ag can be used to regulate the growth of conductive filaments of resistive variable devices. In particular, metals such as copper (Cu), Ag and aluminum (Al) can be used as conductive filaments of photoresistance variable devices on the one hand, and have surface plasmon effects on the other hand. In this case, plasmon hot electrons directly act on the growth and breakage of conductive filaments of photoresistance variable devices without the need for migration. In addition, by selecting different surface plasmon metals as electrodes of photoresistance variable devices, wavelength selectivity at the device level can be achieved, so that the device can have color recognition function. Summary of the invention

[0004] In view of the problems existing in the current image encryption technology, such as the relative separation of image acquisition and encryption at the hardware level, and the vulnerability of software encryption algorithms to machine learning attacks, the present invention provides a plasmon-type two-dimensional material photoresistor variable device, array, and hardware-level in-situ encryption method for color images in the sensor. While completing color image acquisition using the characteristic wavelength of precious metals, a reconfigurable PUF key is generated by means of the randomness of the resistive variable device, thereby improving the security of information encryption and reducing the power consumption of data transmission. In order to develop a photoresistor variable device based on two-dimensional materials and realize in-situ encryption of color images in the sensor, the top electrode of the photoresistor variable device of the present invention uses a precious metal film such as Au and Ag with a surface plasmon effect, uses an insulating two-dimensional material-carbon-doped hexagonal boron nitride as the intermediate dielectric layer of the photoresistor variable device, and the bottom electrode is an inert metal. The localized surface plasmon resonance effect of Au and Ag precious metal films can achieve strong absorption of light with corresponding characteristic wavelengths (600 and 400nm), thereby forming more hot electrons on the metal surface and increasing the local temperature of the metal surface, which in turn causes the filament growth process in the resistive variable device to be regulated by the optical signal, and the response to the external optical signal is completed by increasing the low resistance value, realizing the in-situ encryption of color images in the photoresistive variable device, array and sensor based on two-dimensional materials.

[0005] According to the first aspect of the present specification, a plasmonic two-dimensional material photoresistor variable device is provided, the device comprising a top electrode, an intermediate dielectric layer and a bottom electrode, the top electrode is a surface plasmon noble metal film, the intermediate dielectric layer is an insulating two-dimensional material - carbon-doped hexagonal boron nitride, and the bottom electrode is an inert metal.

[0006] Furthermore, the top electrode serves as a light-absorbing layer and is a thin-film electrode with a specific surface roughness. The plasmon effect of a precious metal with nanometer-level thickness is used to construct a photoresistive resistive variable device, and the precious metal is Au or Ag. The thickness and surface roughness of the top electrode need to satisfy the requirement that the whole is a discontinuous thin film (with several obvious particles) and has good resistive variable characteristics. A thinner (for example, 3nm) discontinuous thin film has light absorption capability but poor resistive variable characteristics of the device, and a thicker (for example, 15nm) continuous thin film has good resistive variable characteristics but poor light absorption capability. Taking all factors into consideration, the thickness of the top electrode can be set to 5nm.

[0007] Furthermore, the intermediate dielectric layer serves as a resistive switching layer with a thickness between 5 and 10 nm; the intermediate dielectric layer realizes boron vacancy defects by carbon doping, specifically, by carbon doping with a mass fraction of 0.6%, the boron-nitrogen atomic ratio in hexagonal boron nitride reaches 0.94:1.

[0008] Furthermore, the bottom electrode is an inert metal electrode with an adhesion layer, the adhesion layer is chromium (Cr) or titanium (Ti) with a thickness of 5 nm, and the inert metal is Au or platinum (Pt) with a thickness of 40 nm.

[0009] The photosensitive filament regulation mechanism of the photoresistor variable device is as follows: the local electric field enhancement at the discontinuous top electrode film particles induces a photothermal effect, making the particles the main heat source, thereby increasing the device temperature and causing the filaments to break; in addition, photogenerated hot electrons inhibit filament growth during the setting process and promote filament disconnection during the resetting process.

[0010] According to a second aspect of this specification, there is provided a method for preparing the device according to the first aspect, comprising:

[0011] The electrode pattern is obtained by ultraviolet lithography, and a bottom electrode is prepared on the substrate by deposition by magnetron sputtering or thermal evaporation;

[0012] A carbon-doped hexagonal boron nitride sheet is obtained by a mechanical stripping method, and the hexagonal boron nitride sheet is transferred to a bottom electrode by a transfer technique to form an intermediate dielectric layer;

[0013] The electrode pattern is obtained by laser direct writing, and a thin film top electrode with a specific surface roughness is prepared by thin film deposition technology; specifically, there are various methods for preparing the top electrode, and the goal is to change the nanostructure of the thin film electrode, thereby controlling the light absorption characteristics of the thin film electrode. Preferably, the top electrode is prepared by a magnetron sputtering method, which can deposit Au or Ag films with larger roughness than thermal evaporation and electron beam evaporation, and has a strong plasmon effect.

[0014] According to the third aspect of the present specification, there is provided a plasmon-type two-dimensional material photoresistor variable device array for sensing internal color image encryption, the array comprising a substrate, the upper surface of the substrate having a plurality of bottom electrodes arranged in an array, the bottom electrode being an inert metal, the upper surface of the bottom electrode being covered with an intermediate dielectric layer, the intermediate dielectric layer being an insulating two-dimensional material - carbon-doped hexagonal boron nitride, the upper surface of the intermediate dielectric layer having a plurality of top electrode groups arranged in an array, each top electrode group comprising two surface plasmon noble metal thin film top electrodes of different characteristic wavelengths; the bottom electrodes serve as the columns of the array, with a total of n columns, the top electrodes serve as the rows of the array, with a total of m rows, forming an m×n array structure, the top electrode group formed by two adjacent rows of top electrodes of different characteristic wavelengths and the corresponding bottom electrode being a pixel, that is, one pixel corresponds to two device structures, and the device array has a total of (m / 2)×n pixels.

[0015] Furthermore, each top electrode group includes an Au thin film top electrode and an Ag thin film top electrode with different roughness, that is, a single pixel has an Au photoresistive variable device formed by an Au thin film top electrode, an intermediate dielectric layer and a bottom electrode, and an Ag photoresistive variable device formed by an Ag thin film top electrode, an intermediate dielectric layer and a bottom electrode; when the top electrode thickness is 5 nm, the root mean square (RMS) roughness of the Au thin film top electrode and the Ag thin film top electrode prepared by magnetron sputtering is approximately 1.57 and 4.28 nm, respectively.

[0016] According to a fourth aspect of the present specification, there is provided a method for preparing the device array according to the third aspect, comprising:

[0017] A bottom electrode array pattern is obtained by ultraviolet lithography, and a plurality of bottom electrodes arranged in an array are prepared on a substrate by deposition by magnetron sputtering or thermal evaporation;

[0018] A carbon-doped hexagonal boron nitride sheet is obtained by a mechanical stripping method, and the hexagonal boron nitride sheet is transferred to a bottom electrode by a transfer technique to form an intermediate dielectric layer;

[0019] The top electrode array pattern is obtained by laser direct writing, and the surface plasmon noble metal thin film top electrodes with different characteristic wavelengths are prepared by thin film deposition technology.

[0020] According to a fifth aspect of the present specification, there is provided a method for testing the device array as described in the third aspect, comprising:

[0021] The bottom electrode is grounded, a bias is applied to the top electrode, and a positive voltage is gradually applied from small to large until an electrical activation process occurs, and then a reset is performed (a negative voltage is applied), and then a set (a positive voltage is applied) and a reset are performed in sequence to train the conductive filament to achieve a smaller closing and opening voltage (the opening voltage of Ag is about 0.6V, and the closing voltage is about -0.3V, and the opening voltage of Au is about 3.6V, and the closing voltage is about -0.8V), and finally a stable resistive switching characteristic of the photoresistive variable device is obtained;

[0022] By applying light of different wavelengths above the device, the resistive switching characteristics of the photoresistor variable device are regulated through the plasmon effect of the nano-thick precious metal film, thereby realizing the perception and storage of light.

[0023] According to a sixth aspect of the present specification, a method for encrypting an intra-sensing color image based on the device array according to the third aspect is provided, comprising the following steps:

[0024] S1, collect color images, including:

[0025] S11, setting two device structures corresponding to a certain pixel to a low resistance state under a dark state condition, and reading a dark current in the low resistance state;

[0026] S12, setting the two device structures corresponding to the pixel to a low resistance state under different illumination conditions, reading the photocurrent in the low resistance state; comparing the photocurrent and dark current in the low resistance state to complete color image acquisition;

[0027] S2, generating a reconfigurable PUF, including: resetting the two device structures of the pixel in the low-resistance state to the high-resistance state, reading the resistance value of the high-resistance state, and comparing it with the set reference resistance value to obtain a dual-binary PUF key;

[0028] S3, encryption and decryption of color images within the sensor: Use the dual binary PUF key obtained in S2 to perform an XOR operation on the color image collected by S1 to complete the encryption of the color image within the sensor; use the dual binary PUF key obtained in S2 to perform an XOR operation on the encrypted color image within the sensor to achieve decryption of the color image within the sensor.

[0029] The present invention has the advantages that:

[0030] 1. In the two-dimensional photoresistor variable device, the plasmon effect of the precious metal film is introduced into the conductive filament type resistive variable device to realize the regulation effect of the optical signal on the conductive filament and establish a plasmon type photoresistor variable device.

[0031] 2. The visible light wavelength selection of the photoresistor variable device is realized based on the surface plasmon effect of different precious metal films. Two devices composed of different precious metal films constitute a pixel, thereby realizing color image acquisition.

[0032] 3. Prepare two-dimensional plasmonic photoresistance-variable devices based on different precious metal films, and use the randomness of the resistive device to generate reconfigurable PUF keys while collecting color images, thereby realizing in-sensor color image encryption, reducing data transmission, improving efficiency, reducing power consumption, and increasing key randomness and improving security. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the preparation of the plasmon type photoresistor variable device and the photoelectric characteristics test setup in Example 1 ( Figure 1 (c));

[0034] Figure 2 The photoresistance variable characteristics of the Au and Ag thin film plasmon type photoresistance variable devices in Example 2 under 600 and 400 nm light ( Figure 2 (a) and Figure 2 (c)) and the difference in photoresistance between devices ( Figure 2 (b) and Figure 2 (d));

[0035] Figure 3The SEM (Scanning Electron Microscope) of Au and Ag metal films in Example 3 ( Figure 3 (a) and Figure 3 (b)) and AFM (Atomic Force Microscope) ( Figure 3 (c) and Figure 3 Middle (d) image;

[0036] Figure 4 is Au( Figure 4 (a) and Figure 4 (b)), Ag( Figure 4 (c) and Figure 4 (d) Light-controlled filament regulation mechanism of plasmonic photoresistor inverter;

[0037] Figure 5 is Au( Figure 5 (a)), Ag( Figure 5 (b)) Local electric field enhancement of noble metal film plasmon effect and corresponding photothermal effect;

[0038] Figure 6 is the UV-visible extinction spectrum of the ultra-thin Ag, Au noble metal film / hexagonal boron nitride / Si in Example 4 ( Figure 6 (a)) and the pixel structure of dichroic color image acquisition ( Figure 6 (b) and Figure 6 (c));

[0039] Figure 7 is the resistance distribution range of the high-resistance state of the Au and Ag plasmon resistive switching devices in Example 5 ( Figure 7 (a) and Figure 7 (b)) and the high-resistance resistance used to generate the reconfigurable PUF key ( Figure 7 (c) and Figure 7 (d));

[0040] Figure 8 It is a schematic diagram of encryption and decryption of a color image in the sixth embodiment. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0043] Example 1

[0044] Combination Figure 1 The preparation process of the isotropic two-dimensional material photoresistor variable device array in Example 1 is described.

[0045] The preparation process of the isotropic two-dimensional material photoresistor variable device array in Example 1 comprises the following steps:

[0046] Step 1, bottom electrode preparation (such as Figure 1 (a)): After cleaning and drying a 4-inch silicon wafer (SiO2 / Si) with 10 ml of acetone, isopropanol, alcohol and deionized water for 1 min, AR-P 5350 positive photoresist is used for spin coating at a rotation speed of 4000 rpm for 1 min, dried at 105°C for 5 min, UV-exposed for 3.3 s and developed for about 50 s to make a bottom electrode array pattern with a certain line width on the silicon wafer, the line width is 2, 3, 4 or 6 μm. The inert metal Au bottom electrode with Cr as the adhesion layer is deposited by thermal evaporation or magnetron sputtering technology, and the Cr / Au thickness is 5 / 40 nm respectively. The key technical parameters of thermal evaporation deposition of Cr / Au are material density 7.2 / 19.3, material acoustic impedance ratio 0.305 / 0.381, scale factor 1 / 1.7, vacuum degree 3×10 -4 Pa, deposition rate 1, temperature 20°C. The key technical parameters of magnetron sputtering deposition of Cr / Au are power 100 / 200 W, deposition rate 12 / 60 nm / min, vacuum degree 1×10 -2 Torr.

[0047] Step 2, preparation of intermediate medium material (such as Figure 1 (b) shows that a 7 nm thick insulating two-dimensional material, carbon-doped hexagonal boron nitride, is obtained by mechanical stripping, adhered to PDMS (polydimethylsiloxane), and then transferred to a silicon wafer with a bottom electrode by a transfer platform under heating at 80°C. Wrinkles and breaks are avoided as much as possible during the transfer process.

[0048] Step 3, top electrode preparation (such as Figure 1(c) shows that: the silicon wafer after transfer is soaked in acetone to remove the dirt introduced during the transfer process; the silicon wafer is spin-coated with AR-P 5350 positive photoresist and dried at 105°C for 5 minutes; a top electrode array pattern with a line width of 4μm is prepared by laser direct writing lithography, with an exposure dose of 64mW, and soaked in developer for 50s to prevent over-development; then a 5nm thick Ag and Au thin film top electrode is deposited by thermal evaporation or magnetron sputtering technology, and then cleaned and peeled with acetone. The key technical parameters of thermal evaporation deposition of Ag are material density 10.5, material acoustic impedance ratio 0.529, scale factor 1, vacuum degree 3×10 -4 Pa, deposition rate 1, temperature 20°C. The main technical parameters of magnetron sputtering deposition of Ag are power 40W, rate 21nm / min, vacuum degree 1×10 -2 Torr.

[0049] Example 2

[0050] Combination Figure 1 (c) and Figure 2 The method for testing the photoresistance variable performance of the plasmon type two-dimensional material photoresistance variable device array in Example 2 is described.

[0051] The method for testing the photoresistance variable performance of the isotropic two-dimensional material photoresistance variable device array in Example 2 is specifically as follows:

[0052] The ultra-thin Ag or Au noble metal top electrode is connected to the power supply, and the inert metal bottom electrode is grounded. Using Keilthy digital source meter 2450 or 2636A, the current is controlled to be limited to 1×10 -4 or 1×10 -5 A, generate conductive filaments with appropriate thickness, position and quantity, so that the resistive switching device is in an activated state. Further, under the stimulation of a DC voltage signal, the conductive filaments are trained through repeated positive voltage setting and negative voltage resetting operations to obtain a resistive switching device with stable performance such as cycling and retention.

[0053] The plasmonic two-dimensional material photoresistor variable device based on Ag and Au noble metals can be used in visible light with wavelengths of 400 and 600 nm (with light intensities of 55 and 53 mW / cm 2 ) to test the effect of light on the electrical resistance of the device. The current-voltage curve obtained by the test and the stability of the photoresistance of different devices are shown in Figure 2. Figure 2 As shown, the results show that under light conditions, the resistance of the low-resistance state of Ag and Au precious metal devices increased from 1 to 10Ω and 0.1 to 1Ω to 10 to 100Ω.

[0054] Example 3

[0055] Combination Figure 3 , Figure 4 , Figure 5 And the light-controlled filament control mechanism of a plasmonic photoresistor variable device in Example 3 is explained.

[0056] The present invention provides a light absorption property of a plasmon ultra-thin metal film. The SEM and AFM images of a 5nm thick discontinuous Au and Ag metal film are shown in Figure 2. Figure 3 The diameters of the 5nm thick Au and Ag thin film particles are 18 and 14nm respectively. Figure 3 (a) and Figure 3 The RMS roughness of Au and Ag metal films are approximately 1.74 and 4.28 nm, respectively. Figure 3 (c) and Figure 3 As shown in the AFM image in (d).

[0057] The light-controlled filament control mechanism of the photoresistor variable device is that under the irradiation of incident light with a wavelength of 600 and 400 nm, the photo-generated hot electrons due to the plasmon effect can inhibit the growth of boron vacancies or Ag metal conductive filaments during the setting process ( Figure 4 (a) and Figure 4 (c)), or promote the disconnection of boron vacancies or Ag metal conductive filaments during the reset process ( Figure 4 (b) and Figure 4 In addition, the plasmon photothermal effect helps to promote the disconnection of the conductive filaments ( Figure 5 ), thereby increasing the resistance value in the low-resistance state.

[0058] Example 4

[0059] Combination Figure 6 A color image acquisition method based on a plasmon-type two-dimensional material photoresistor variable device array in Example 4 is described.

[0060] The present invention provides a color image acquisition method based on a plasmon type two-dimensional material photoresistor variable device array. The light absorption extinction spectrum of ultra-thin Ag and Au precious metal films is as follows: Figure 6 As shown, its peaks are 370 and 515nm ( Figure 6 In (a), the light absorption rate of incident light with wavelengths of 400 and 600 nm is greater than 50%, which is close to the absorption peaks of the two cone cells of the human visual system (420 and 558 nm), and can be used to simulate color image acquisition based on dichromatic vision ( Figure 6 (b)). A single pixel contains two resistive switching device structures, Ag and Au, which are sensitive to 400 and 600 nm wavelength light, respectively, thus forming a 3×3 pixel array ( Figure 6 (c)).

[0061] In the dark state, the Ag and Au photoresistance variable devices are set from a high resistance state to a low resistance state, and the dark current in the low resistance state is read.

[0062] Under 400 and 600nm illumination conditions, the device is set to a low-resistance state and the photocurrent in the low-resistance state is read. The photocurrent and dark current in the low-resistance state are compared to complete the color image acquisition. In a pixel, both devices have an obvious photocurrent of "11", both have no obvious photocurrent of "00", and any device has an obvious photocurrent of "10" or "01".

[0063] Example 5

[0064] Combination Figure 7 A reconfigurable PUF generation method in Example 5 is described.

[0065] The present invention provides a reconfigurable PUF generation method. The device is reset from a low resistance state to a high resistance state, and the resistance value of the high resistance state is read. The high resistance value ranges of Au and Ag devices are 10 4 ~10 8 Ω and 10 5 ~10 8 Ω( Figure 7 (a) and Figure 7 (b)). Set the reference resistance to 10MΩ, compare the high-resistance resistance with the reference resistance, and obtain the binary PUF key. That is, if the Au and Ag resistances are all greater than 10MΩ, it is "11", if they are all less than 10MΩ, it is "00", and if one of them is greater than 10MΩ, it is "10" or "01" ( Figure 7 (c) and Figure 7 (d)).

[0066] The uniformity, uniqueness and stability of the obtained reconfigurable PUF key are evaluated, and parameters such as Hamming weight, intra-chip Hamming distance and inter-chip Hamming distance are extracted. Their values ​​are 0.5, 0.5 and 0.903, respectively, which are close to the ideal values ​​of 0.5, 0.5 and 1.

[0067] Example 6

[0068] Combination Figure 8 A color image encryption method in Example 6 is described.

[0069] The present invention provides a method for encrypting color images in a sensor. A plasmon type photoresistor variable device is used to generate a PUF key while collecting color images, and the PUF key is used to perform an XOR operation on the collected color images, thereby completing the encryption and decryption operations of the color images in the sensor. Figure 8 Schematic diagram of encryption and decryption of color images.

[0070] The above description is merely a preferred embodiment of one or more embodiments of the present specification and is not intended to limit one or more embodiments of the present specification. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present specification shall be included in the scope of protection of one or more embodiments of the present specification.

Claims

1. A plasmonic two-dimensional material photoresistor variable device, characterized in that: The device includes a top electrode, an intermediate dielectric layer and a bottom electrode. The top electrode is a surface plasmon noble metal film, the intermediate dielectric layer is an insulating two-dimensional material - carbon-doped hexagonal boron nitride, and the bottom electrode is an inert metal. The top electrode serves as a light-absorbing layer and is a thin-film electrode with a specific surface roughness, that is, the surface has several obvious particles. The photoresistor variable device is constructed by utilizing the plasmon effect of a nanometer-thick noble metal film, and the noble metal is gold or silver.

2. The device according to claim 1, characterized in that The intermediate dielectric layer serves as a resistive switching layer and has a thickness between 5 and 10 nm. The intermediate dielectric layer realizes boron vacancy defects through carbon doping.

3. The device according to claim 1, characterized in that The bottom electrode is an inert metal electrode with an adhesion layer, the adhesion layer is chromium or titanium, and the inert metal is gold or platinum.

4. A method for preparing the device according to any one of claims 1 to 3, characterized in that: include: The electrode pattern is obtained by ultraviolet lithography, and a bottom electrode is prepared on the substrate by deposition using magnetron sputtering or thermal evaporation; A carbon-doped hexagonal boron nitride sheet is obtained by mechanical stripping, and the hexagonal boron nitride sheet is transferred to the bottom electrode by transfer technology to form an intermediate dielectric layer; The electrode pattern is obtained by laser direct writing, and a thin film top electrode with a specific surface roughness is prepared using thin film deposition technology.

5. A plasmonic two-dimensional material photoresistor variable device array, characterized in that: The array includes a substrate, the upper surface of the substrate has a plurality of bottom electrodes arranged in an array, the bottom electrodes are inert metals, the upper surface of the bottom electrodes is covered with an intermediate dielectric layer, the intermediate dielectric layer is an insulating two-dimensional material - carbon-doped hexagonal boron nitride, the upper surface of the intermediate dielectric layer has a plurality of top electrode groups arranged in an array, each top electrode group includes two surface plasmon noble metal thin film top electrodes with different characteristic wavelengths; the bottom electrodes serve as the columns of the array, and there are a total of n Columns, top electrodes as rows of the array, total m Line, form m × n In the array structure, a top electrode group formed by two adjacent rows of top electrodes with different characteristic wavelengths and the corresponding bottom electrodes serve as a pixel, that is, one pixel corresponds to two device structures.

6. The device array according to claim 5, characterized in that Each top electrode group includes a gold thin film top electrode and a silver thin film top electrode with different roughness, that is, a single pixel has a gold photoresistive variable device formed by a gold thin film top electrode, an intermediate dielectric layer and a bottom electrode, and a silver photoresistive variable device formed by a silver thin film top electrode, an intermediate dielectric layer and a bottom electrode.

7. A method for preparing the device array according to claim 5 or 6, characterized in that: include: A bottom electrode array pattern is obtained by ultraviolet lithography, and a plurality of bottom electrodes arranged in an array are prepared on a substrate by deposition using magnetron sputtering or thermal evaporation; A carbon-doped hexagonal boron nitride sheet is obtained by mechanical stripping, and the hexagonal boron nitride sheet is transferred to the bottom electrode by transfer technology to form an intermediate dielectric layer; The top electrode array pattern is obtained by laser direct writing, and the surface plasmon noble metal thin film top electrodes with different characteristic wavelengths are prepared by thin film deposition technology.

8. A method for testing the device array according to claim 5 or 6, characterized in that: include: The bottom electrode is grounded, a bias is applied to the top electrode, and a forward voltage is gradually applied from small to large until an electrical activation process occurs, and then reset is performed. The set and reset training of the conductive filament is performed in sequence to obtain a stable resistive switching characteristic of the photoresistive variable device; By applying light of different wavelengths above the device, the resistive switching characteristics of the photoresistor variable device are regulated through the plasmon effect of the nanometer-thick precious metal film, realizing the perception and storage of light.

9. A method for encrypting an internal color image based on the device array according to claim 5 or 6, characterized in that: The following steps are involved: S1, collects color images, including: S11, setting two device structures corresponding to a certain pixel to a low-resistance state under dark conditions, and reading the dark current in the low-resistance state; S12, setting the two device structures corresponding to the pixel to a low-resistance state under different lighting conditions, reading the photocurrent in the low-resistance state; and comparing the photocurrent and dark current in the low-resistance state to complete color image acquisition; S2, generating a reconfigurable physical unclonable function, including: resetting the two device structures of the pixel in a low-resistance state to a high-resistance state, reading the resistance value of the high-resistance state, and comparing it with a set reference resistance value to obtain a dual-binary physical unclonable function key; S3, encryption and decryption of color images within the sensor: Use the dual-binary physical unclonable function key obtained in S2 to perform an XOR operation on the color image collected by S1 to complete the encryption of the color image within the sensor; use the dual-binary PUF key obtained in S2 to perform an XOR operation on the encrypted color image within the sensor to achieve decryption of the color image within the sensor.

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