A high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor, its fabrication method, and its application.

Abstract

This invention discloses a highly self-assembled dual quantum dot / graphene heterojunction broadband memristor, its fabrication method, and its applications, belonging to the field of inorganic semiconductor technology. The method includes the following steps: mixing highly self-assembled cerium oxide quantum dot ink and PbS quantum dot ink with a graphene dispersion and stirring until homogeneous to form a uniformly loaded quantum dot / graphene dispersion; then using the quantum dot / graphene dispersion to construct a dual quantum dot / graphene heterojunction film on a silicon wafer surface, thus obtaining the dual quantum dot / graphene heterojunction broadband memristor. This invention overcomes the inherent limitations of the photoresponse range of single materials, achieving broadband optoelectronic memristor behavior in the ultraviolet to near-infrared bands. Simultaneously, the memristor of this invention exhibits rich synaptic plasticity under light pulse modulation, providing core support for constructing a novel integrated optoelectronic system for broadband sensing, storage, and processing. It possesses strong technical adaptability and industrialization prospects in cutting-edge fields such as bionic vision, optical neural networks, and intelligent sensing.

Description

Technical Field

[0001] This invention belongs to the field of inorganic semiconductor technology, and particularly relates to an ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor, its preparation method and application. Background Technology

[0002] With the rapid development of artificial intelligence, the Internet of Things, and big data processing technologies, the performance requirements for information storage and processing hardware are becoming increasingly stringent. Memristors, as the fourth basic circuit element after resistors, capacitors, and inductors, have demonstrated significant application value in novel information storage and neuromorphic computing systems due to their advantages such as non-volatile resistive switching characteristics, in-memory computing potential, high integration density, and low power consumption, becoming a research focus for next-generation information devices.

[0003] Currently, introducing optical signals into memristors to achieve optoelectronic control and in-memory computing is a cutting-edge research direction in this field. However, existing memristor technology faces many significant challenges in practical applications. On the one hand, traditional optoelectronic memristors built with single-material systems are limited by the material's own light absorption characteristics, and their photoelectric response range is usually limited to a specific wavelength band. Wide-bandgap semiconductor memristors, represented by hafnium oxide and titanium oxide, have excellent stability and ultraviolet-visible light response capabilities, but their light absorption range is narrow, and their utilization rate of near-infrared light is extremely low. They mainly respond to the short-wavelength region of ultraviolet to visible light, and their response to near-infrared light is weak. On the other hand, devices based on narrow-bandgap semiconductors such as lead sulfide can cover the near-infrared band and effectively absorb near-infrared light, but their chemical stability is poor, and they are prone to oxidation, leading to performance degradation. Furthermore, their compatibility with existing CMOS processes faces challenges. This limitation in spectral response range severely restricts the application potential of such devices in cutting-edge fields such as wide-band optical sensing, bionic vision and full-spectrum optical neural networks, wide-band optical signal detection, retinal-inspired visual systems, and optomorphic computing.

[0004] On the other hand, to achieve a wide-band response, it is generally necessary to integrate multiple sets of devices, which brings additional burdens and challenges to the fabrication, integration, and control of the system. Moreover, a single material system is difficult to overcome the performance bottleneck caused by its intrinsic properties, and current technology lacks memristor structures that can maintain stable and efficient photoelectric response in a wide spectral range from ultraviolet to near-infrared, and have good process compatibility.

[0005] Therefore, how to provide a novel composite functional layer structure that can take into account a wide spectral response, high stability and good process compatibility, so as to resolve the contradiction between material properties and realize continuous and efficient photoelectric conversion from ultraviolet to near infrared is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes an ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor, its fabrication method, and its applications.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for fabricating an ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor includes the following steps: Highly self-assembled cerium oxide quantum dots and infrared-responsive quantum dots are mixed with graphene dispersion and uniformly loaded to form a successfully loaded quantum dot / graphene dispersion. Then, the quantum dot / graphene dispersion is used to construct a dual quantum dot / graphene heterojunction film on the substrate surface to obtain the highly self-assembled dual quantum dot / graphene heterojunction broadband memristor.

[0008] Beneficial Effects: This invention provides a wide-band response memristor based on a graphene-supported cerium oxide and lead sulfide composite structure. Using layered graphene as a substrate, after surface hydroxylation pretreatment to enhance adsorption capacity, highly self-assembled cerium oxide particles and infrared-responsive quantum dots are sequentially modified or co-loaded onto the graphene surface via solution phase deposition. This method can construct high-density cerium oxide / graphene, infrared-responsive quantum dot / graphene, and cerium oxide / lead sulfide heterostructure composite functional layers, significantly enhancing the interface's control over carrier transport. This provides structural support for the device's wide-band response and high stability, effectively solving the difficulties in device fabrication and integration, and overcoming the inherent limitations of single-material systems in terms of response band and stability.

[0009] The core innovation of this invention lies in the creative fabrication of highly self-assembled wide-bandgap semiconductor cerium oxide and narrow-bandgap semiconductors with infrared response quantum dots, while uniformly attaching them to highly dispersed and hydrophilic graphene, thereby preparing a semiconductor ink capable of large-area printing. This ink can then be effectively printed onto various substrates to achieve uniform, dense, and large-area printable semiconductor films. The constructed semiconductor functional layer possesses synergistic advantages of electrical control and wide-band optical modulation. Graphene not only provides a stable loading platform for the two semiconductor materials, but its ultra-high carrier mobility can also build efficient conductive channels. Simultaneously, its high specific surface area promotes the uniform dispersion of cerium oxide and lead sulfide, avoiding agglomeration. Cerium oxide possesses excellent chemical stability and UV-Vis response characteristics, while the infrared-responsive quantum dots endow the device with strong near-infrared light absorption capabilities. The synergistic effect of these three elements not only effectively extends the spectral response range from ultraviolet to near-infrared, but also creates a built-in electric field that facilitates carrier separation and transport through interface band engineering. Combined with the high conductivity of graphene, this significantly improves the photoelectric response efficiency and stability of the device across the entire wavelength range. At the same time, the mechanical support of graphene further enhances the structural stability of the composite structure.

[0010] Preferably, the method for preparing the graphene dispersion includes the following steps: 0.005 g of graphene was dispersed in 5 mL of water and continuously irradiated with an ultraviolet light source for 1 h to obtain the graphene dispersion.

[0011] More preferably, the graphene is layered graphene.

[0012] More preferably, the ultraviolet light has a wavelength of 365 nm and an intensity of 150 mW / cm². 2 .

[0013] More preferably, the method for constructing ultra-high self-assembled dual quantum dot / graphene heterojunction thin films is to utilize liquid phase layered film formation technology; More preferably, the method for constructing the dual quantum dot / graphene heterojunction film is to perform spin coating in successive steps, with a single coating amount of 10 μL, and to treat under ultraviolet light at a wavelength of 250 nm for 30 min after each spin coating.

[0014] More preferably, the spin coating is performed three times, and the resulting film is subjected to an additional 3 hours of 250nm ultraviolet light treatment after each spin coating.

[0015] More preferably, the average thickness of the dual quantum dot / graphene heterojunction film is 100-300 nm.

[0016] Preferably, the substrate is a silicon wafer with gold-plated electrodes or an ITO flexible conductive substrate.

[0017] Preferably, the mass ratio of the cerium oxide quantum dots and PbS quantum dots to the graphene dispersion is 4:2:1.

[0018] Preferably, the method for preparing the cerium oxide quantum dots includes the following steps: A cerium salt solution, toluene, oleic acid, and tert-butylamine are placed in a reaction vessel to form a hydrolysis-free oil-water interface. The reaction is carried out under hydrothermal conditions. After the reaction is completed, the upper organic phase is washed, the precipitated solid is centrifuged, and the solid precipitate is collected to obtain the cerium oxide quantum dots.

[0019] Preferably, the reaction temperature under the hydrothermal conditions is 200°C and the reaction time is 36 hours.

[0020] Preferably, the volume ratio of the cerium salt solution, toluene, oleic acid and tert-butylamine is 12:12:0.2:0.2.

[0021] The concentration of the cerium salt solution is 16-17 mmol / L.

[0022] Preferably, the infrared-responsive quantum dot is a PbS quantum dot or a cadmium telluride quantum dot. The method for preparing the PbS quantum dots includes the following steps: Lead oxide, oleic acid, and 1-octadecene (ODE) were mixed and degassed. The mixture was stirred and reacted under an inert atmosphere and heating conditions, then cooled. A mixture of trimethylsilyl iodine and 1-octadecene was then injected to continue the reaction. The reaction was then terminated under ice bath conditions. Acetone was added to the reaction system for precipitation, followed by centrifugation. The resulting precipitate was dispersed in toluene to obtain the PbS quantum dots.

[0023] Preferably, the ratio of lead oxide, oleic acid and trimethylsilyl iodine added is 0.9g:3mL:420μL.

[0024] More preferably, the degassing temperature is 60°C and the time is 15 minutes.

[0025] Preferably, the heating conditions are at a temperature of 140°C and a time of 1 hour; The cooling temperature is 100°C.

[0026] Preferably, the temperature for the continued reaction is 100°C and the time is 60 seconds.

[0027] More preferably, the mass ratio of the precipitate to water is 1:2.

[0028] A highly self-assembled dual quantum dot / graphene heterojunction broadband memristor prepared by the method described above.

[0029] Beneficial Effects: This invention demonstrates the performance and reliability of the structure using cerium oxide and infrared-responsive quantum dots as examples. By constructing a composite functional layer of graphene heterostructure with a wide-bandgap cerium oxide and a narrow-bandgap lead sulfide quantum dots, this structure not only effectively broadens the spectral response range, covering the ultraviolet, visible, and near-infrared bands, but also utilizes the bandgap matching and synergistic effect between the two materials to promote the separation and transport of photogenerated carriers, thereby improving the photoelectric response efficiency and overall stability of the device. This provides an effective technical path to overcome the limitations of single-material systems in wide-band photoelectric memristors.

[0030] Applications of an ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor in the fields of biomimetic vision, optical neural networks and intelligent sensing.

[0031] Compared with the prior art, the present invention has the following advantages and technical effects: This invention utilizes an ultra-highly self-assembled dual quantum dot / graphene two-dimensional thin film material as the resistive switching functional layer of a memristor, achieving the assembly of a heterojunction broadband memristor. Using highly conductive and high specific surface area graphene as the loading substrate, this invention creatively combines cerium oxide quantum dots and lead sulfide quantum dots to construct the functional layer, completely overcoming the inherent limitations of the photoresponse range of single materials and successfully realizing broadband optoelectronic memristor behavior in the ultraviolet to near-infrared bands. This composite system, through the synergistic effect of interface bandgap engineering and graphene, not only broadens the spectral response dimension but also simultaneously improves the device's on / off ratio, cycle durability, and data retention capability, solving the pain point of traditional devices struggling to achieve a balance between performance. Furthermore, the memristor obtained by this invention exhibits rich synaptic plasticity under optical pulse modulation, providing core support for constructing a novel broadband integrated optoelectronic system of sensing, storage, and processing. It possesses strong technical adaptability and broad industrialization prospects in cutting-edge fields such as bionic vision, optical neural networks, and intelligent sensing. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart illustrating the fabrication process of the ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor in Example 1. Figure 2 A schematic diagram of the design of a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor in Example 1; Figure 3 This is a SEM image of the ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor in Example 1; In the image, A is a front view of the SEM image of the memristor; B is a side view of the SEM image of the memristor. Figure 4 These are TEM images of the graphene and the resulting ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor from Example 1. In the image, A is a TEM image of graphene; B is a TEM image of graphene loaded with cerium oxide and lead sulfide. Figure 5 This is a physical image of the ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor based on ITO flexible conductive material obtained in Example 2. Figure 6 IV scan tests of the ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor in Example 1 under different illumination conditions; Where A represents darkness, B represents infrared light irradiation, and C represents ultraviolet light irradiation. Figure 7The ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor in Example 1 is used to simulate the memory characteristics of human learning-forgetting-relearning behavior. Where A is induced by ultraviolet light pulses; B is induced by infrared light pulses; Figure 8 This is a test of the modulation of conductivity enhancement by the ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor in Example 1 under ultraviolet light and infrared light pulses. Figure 9 The results show the temperature stability test results of the ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor in Example 1. Figure 10 IV scan test images of the products obtained in Example 1 and Comparative Examples 1-3; Wherein, A is Example 1; B is Comparative Example 1; C is Comparative Example 2; D is Comparative Example 3; Figure 11 The image shows the IV scan results of the cerium oxide and cadmium telluride dual quantum dot / graphene device obtained in Comparative Example 4. In the accompanying diagram, Dark refers to dark conditions, IR refers to infrared light irradiation conditions, and UV refers to ultraviolet light irradiation conditions. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels; The pretreated silicon wafer is a silicon wafer with a gold-plated electrode. The preparation method includes the following steps: take a silicon wafer with an oxide layer with a thickness of 300 nm on the surface, and clean it in acetone, ethanol and deionized water in sequence. After cleaning, cut it into a preset specific size. Use magnetron sputtering, electron beam evaporation and other technologies to deposit a metal bottom electrode with a thickness at the nanoscale on the surface of the silicon wafer, thus obtaining the pretreated silicon wafer.

[0036] Magnetron sputtering involves using argon ions to bombard a gold target at high speed under magnetic field confinement, sputtering gold atoms onto the silicon wafer surface. This method combines high uniformity and adhesion, and specifically includes the following steps: A gold target (purity ≥99.99%) is loaded into a sputtering gun, with the target-substrate distance controlled at 5-10 cm. The power is set to 30-80 W (DC), the Ar flow rate to be 20-30 sccm, the pressure to be 0.2-0.4 Pa, and the deposition rate to be 0.2-1 nm / s for magnetron sputtering deposition. After deposition, the gold is kept under vacuum for 5-10 min to obtain a gold electrode layer with a thickness of approximately 50-200 nm.

[0037] Electron beam evaporation includes the following steps: Using gold grains / wires (purity ≥ 99.999%) as the evaporation source, the mixture is placed in a water-cooled crucible and evacuated to a base vacuum of 5 × 10⁻⁶. -6 ~1×10 -7 To ensure film purity, a higher vacuum is used. The source is switched to gold evaporation, with a power of 500-1000W, a deposition rate of 0.5-2nm / s, and a thickness of 50-200nm. Once the rate stabilizes, it can be increased to 3nm / s for electron beam evaporation. After electron beam evaporation, vacuum cooling is maintained for 5 minutes to prevent thermal stress from causing film cracking, resulting in a gold electrode layer with a thickness of approximately 50-200nm.

[0038] The ITO flexible conductive substrate was purchased from Luban (Liaoning) Innovation Technology Co., Ltd., with specifications of ITO / PETGN10B.

[0039] Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3℃.

[0040] Example 1 A method for fabricating a broadband memristor with ultra-high self-assembled dual quantum dot / graphene heterojunction, such as... Figure 1 As shown, it includes the following steps: (1) Mix 0.9g of lead oxide, 3mL of oleic acid and 36mL of ODE evenly, degas at 60℃ for 15min, then rapidly heat the mixture to 140℃ and stir for 1h under nitrogen atmosphere. After stirring, let the mixture cool naturally to 100℃, then quickly inject 420μL of the mixture of trimethylsilyl iodine and 18mL of ODE. After reacting at 100℃ for 60s, place it in an ice bath to cool and terminate the reaction. Then add acetone to the reaction system to obtain crude PbS quantum dots. After centrifuging the crude PbS quantum dots at 6000r / min, take 0.1g of the precipitate and redisperse it in 2ml of water to obtain PbS quantum dots.

[0041] (2) Add 12 mL of toluene, 0.2 mL of oleic acid and 0.2 mL of tert-butylamine to 12 mL of Ce(NO3)3·6H2O aqueous solution with a concentration of 16.7 mmol / L to construct an oil-water two-phase interface. Then transfer it to a reaction vessel and seal it. Heat it to 200℃ and react for 36 h. After the reaction is completed, take 2 mL of the upper organic phase for washing and centrifugation to obtain high-purity CeO2 nanocrystals, namely CeO2 quantum dots.

[0042] (3) Disperse 0.005g of graphene in 5mL of water and use a 365nm ultraviolet light source (intensity 150mW / cm²). 2 After continuous irradiation for 1 hour, the oxygen-containing groups at the edge of the graphite were directionally migrated by photogenerated charge carriers. Then, the two quantum dots obtained in steps (1) and (2) were added, and the mixed system was placed in a constant temperature water bath at 45°C. The mixture was continuously stirred magnetically (500 rpm) for 1 hour, and the layer-by-layer separation of the graphite sheets was triggered by the fluid shear force. At the same time, the two quantum dots were uniformly loaded on the graphene sheet to obtain a successfully loaded quantum dot / graphene dispersion.

[0043] (4) Constructing a dual quantum dot / graphene heterojunction film using a stepwise spin-coating-UV crosslinking film formation technique: 10 μL of successfully loaded quantum dot / graphene dispersion was spin-coated onto a 1.5 cm thick film. 2 On a pretreated silicon wafer, a double quantum dot / graphene heterojunction film is obtained. After each layer is coated, it needs to be treated under ultraviolet light at a wavelength of 250 nm for 30 minutes. The above coating and ultraviolet light treatment steps are repeated three times to increase the film thickness. To obtain a dry and uniform film, after the three-layer coating is prepared, the film needs to be subjected to an additional 3 hours of ultraviolet light treatment to form a uniform two-dimensional film material with a total thickness of about 150 nm. The entire process achieves nanoscale thickness control and interface structure optimization through step-by-step film formation, avoiding agglomeration defects, and finally obtaining an ultra-highly self-assembled double quantum dot / graphene heterojunction broadband memristor.

[0044] Example 2 A method for fabricating an ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor, differing from Example 1 only in that the pretreated silicon wafer is replaced with an ITO flexible conductive substrate of equal area, specifically including the following steps: Steps (1)-(3) are the same as in Example 1.

[0045] (4) Constructing a dual quantum dot / graphene heterojunction film using a stepwise spin-coating-UV crosslinking film formation technique: 10 μL of successfully loaded quantum dot / graphene dispersion was spin-coated onto a 1.5 cm thick film. 2A double quantum dot / graphene heterojunction thin film was obtained on an ITO flexible conductive substrate. After each coating layer, it was treated under ultraviolet light at a wavelength of 250 nm for 30 minutes. This coating and ultraviolet light treatment process was repeated three times to increase the film thickness. To obtain a dry and uniform film, after the three-layer coating was completed, the film was subjected to an additional 3 hours of ultraviolet light treatment to form a uniform two-dimensional thin film material with a total thickness of approximately 150 nm. The entire process, through step-by-step film formation, achieved nanoscale thickness control and interface structure optimization, avoiding agglomeration defects, and finally obtained an ultra-highly self-assembled double quantum dot / graphene heterojunction broadband memristor based on the ITO flexible conductive material substrate. Its physical image is shown below. Figure 5 As shown.

[0046] Comparative Example 1 The only difference from Example 1 is that PbS quantum dots are not included; all other process steps and parameters are the same as in Example 1.

[0047] Comparative Example 2 The only difference from Example 1 is that CeO2 quantum dots are not included; all other process steps and parameters are the same as in Example 1.

[0048] Comparative Example 3 The only difference from Example 1 is that it does not include PbS quantum dots and CeO2 quantum dots; all other process steps and parameters are the same as in Example 1.

[0049] Comparative Example 4 The only difference from Example 1 is that PbS quantum dots are replaced with an equal amount of cadmium telluride quantum dots. All other process steps and parameters are the same as in Example 1, yielding a cerium oxide / cadmium telluride dual quantum dot / graphene device. The preparation method of the cadmium telluride quantum dots includes the following steps: Cadmium chloride was used as the cadmium source and sodium tellurite as the tellurium source. They were dissolved in deionized water at a 1:1 molar ratio. Citric acid was added as a complexing agent to adjust the pH to 6-7. The mixture was then transferred to a polytetrafluoroethylene autoclave and kept at 180℃ for 12 h. After natural cooling, the precipitate was collected by centrifugation, washed alternately with anhydrous ethanol and water, and dried under vacuum at 60℃ to obtain CdTe nanoparticles, i.e., cadmium telluride quantum dots.

[0050] Technical effects: 1. Performance Characterization Figure 2 This is a schematic diagram of the structural design of the memristor fabricated in this embodiment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations are shown below. Figures 3-4 As shown.

[0051] Depend on Figure 4 As can be seen from Part A, the high wrinkle properties of graphene provide abundant attachment sites for quantum dots; from Figure 1 ,Figure 2 , Figure 4 In section B, it can be observed that CeO2 and PbS quantum dots are uniformly distributed on the surface of the graphene film, forming a large number of "dual quantum dot-graphene" electronic conduction interfaces. Figure 3 Part A Figure 3 Part B shows the front and cross-sectional SEM images of the memristor prepared by the "dual quantum dot-graphene" ink printing, respectively. It can be seen that the printed film has both uniformity and density, and has the potential to be used as the core structure of thin film devices such as memristors and thin film transistors.

[0052] 2. IV scan test The heterojunction wideband memristor obtained in Example 1 was subjected to IV scan testing, including the following steps: under different illumination conditions (A. dark conditions; B. ultraviolet light irradiation conditions with a wavelength of 365nm; C. infrared light irradiation conditions with a wavelength of 980nm), the device was subjected to current-voltage scan testing, and the scan voltage range was set to -5 V to +5 V.

[0053] Test results are available Figure 6 ,Depend on Figure 6 It can be seen that the device exhibits good memristor characteristics, is able to complete the state transition between high resistance and low resistance states under ±5V voltage, and is distinguishable to different wavelengths of light.

[0054] 3. Test on the modulation of conductance enhancement / suppression by electrical pulse signals The heterojunction broadband memristor obtained in Example 1 was subjected to tests on the modulation of conductance enhancement / suppression by electrical pulse signals, including the following steps: Under a constant bias voltage of 0.1 V, the photocurrent response of the device to ultraviolet light (wavelength λ=365 nm) and infrared light (wavelength λ=980 nm) was analyzed over time. The experiment involved alternating illumination and shutdown cycles (each lasting 10 s). The results are shown in […]. Figure 7 As can be seen, the heterojunction wideband memristor has good response to both ultraviolet and infrared light, and the resistance of the electronically controlled pulse has a slowly changing characteristic.

[0055] 4. Testing the modulation effect of ultraviolet and infrared light pulses on conductivity enhancement The heterojunction broadband memristor obtained in Example 1 was subjected to tests on the modulation of conductance enhancement by ultraviolet and infrared light pulses, including the following steps: Under a constant bias voltage of 0.1 V, in each cycle, the UV / IR light pulse was first turned on to modulate the device to the on state and the current was recorded synchronously. The device was then turned off with -5 V and the current was recorded again to complete one cycle. This process was repeated until the cycle was completed. The results are shown in […]. Figure 8 .

[0056] It can be seen that the conductance of the heterojunction broadband memristor differs significantly under ultraviolet and infrared light pulses. This difference in conductance enhancement under different light pulses further proves that the heterojunction broadband memristor has a unique response capability to different wavelengths of light, providing strong experimental evidence for its application in fields such as optical signal processing.

[0057] 5. Temperature stability The heterojunction broadband memristor prepared in Example 1 was subjected to temperature-dependent stability testing, including the following steps: the device was tested at temperatures of 20, 40, 60, 80, and 100°C with a bias voltage of 0.1V. The resistance values ​​were recorded under dark conditions, ultraviolet light (wavelength λ=365 nm), and infrared light (wavelength λ=980 nm) irradiation, respectively, with 20 records recorded at each temperature. The results are shown below. Figure 9 .

[0058] It can be seen that the resistance of the device maintains a certain stability at temperatures ranging from 20 to 100℃, indicating that the memristor has reliable application prospects over a wide temperature range. Whether in a normal temperature environment or a high-temperature working environment, it can maintain a relatively stable resistance state and will not experience drastic fluctuations in resistance value due to large temperature changes, thus affecting its normal function as a memristor and other devices. This provides strong performance support for the application of the memristor in real-world complex environments.

[0059] Under different illumination conditions (A. darkness, B. ultraviolet light with a wavelength of 365 nm, C. infrared light with a wavelength of 980 nm), current-voltage scan tests were performed on the device, with the scan voltage range set from -5 V to +5 V. For example... Figure 10 In the figures, A is the IV scan test pattern of the ultra-high self-assembled dual quantum dot / graphene heterojunction wideband memristor obtained in Example 1; B is the IV scan test pattern of the product obtained in Comparative Example 1; C is the IV scan test pattern of the product obtained in Comparative Example 2; and D is the IV scan test pattern of the product obtained in Comparative Example 3. It can be seen that the heterojunction wideband memristor obtained in Example 1 of the present invention has the best response performance and stability.

[0060] Under different illumination conditions (A. darkness, B. ultraviolet light with a wavelength of 365 nm, C. infrared light with a wavelength of 980 nm), current-voltage scan tests were performed on the cerium oxide and cadmium telluride dual quantum dot / graphene device obtained in Comparative Example 4, with the scan voltage range set from -5 V to +5 V. Figure 11 It can be seen that the device responds to both infrared and ultraviolet light.

[0061] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for fabricating a broadband memristor with ultra-high self-assembled dual quantum dot / graphene heterojunction, characterized in that, Includes the following steps: Highly self-assembled cerium oxide quantum dots and infrared-responsive quantum dots are mixed with graphene dispersion and uniformly loaded to form a successfully loaded quantum dot / graphene dispersion. Then, the quantum dot / graphene dispersion is used to construct a dual quantum dot / graphene heterojunction film on the surface of a silicon wafer, thus obtaining the highly self-assembled dual quantum dot / graphene heterojunction broadband memristor.

2. The method for fabricating a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor according to claim 1, characterized in that, The preparation method of the graphene dispersion includes the following steps: Graphene is dispersed in water and continuously irradiated with an ultraviolet light source to obtain the graphene dispersion.

3. The method for fabricating a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor according to claim 1, characterized in that, The method for preparing the cerium oxide quantum dots includes the following steps: A cerium salt solution, toluene, oleic acid, and tert-butylamine are placed in a reaction vessel to form a hydrolysis-free oil-water interface. The reaction is carried out under hydrothermal conditions. After the reaction is completed, the upper organic phase is washed, the precipitated solid is centrifuged, and the solid precipitate is collected to obtain the cerium oxide quantum dots.

4. The method for fabricating a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor according to claim 3, characterized in that, The reaction under the hydrothermal conditions was carried out at a temperature of 200°C for 36 hours.

5. The method for fabricating a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor according to claim 3, characterized in that, The volume ratio of the cerium salt solution, toluene, oleic acid, and tert-butylamine is 12:12:0.2:0.

2. The concentration of the cerium salt solution is 16-17 mmol / L.

6. The method for fabricating a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor according to claim 1, characterized in that, The infrared-responsive quantum dots are lead sulfide quantum dots or cadmium telluride quantum dots. The method for preparing the lead sulfide quantum dots includes the following steps: Lead oxide, oleic acid, and 1-octadecene were mixed and degassed. The mixture was stirred and reacted under an inert atmosphere and heating conditions, then cooled. A mixture of trimethylsilyl iodine and 1-octadecene was then injected to continue the reaction. The reaction was then terminated under ice bath conditions. Acetone was added to the reaction system for precipitation, and the mixture was centrifuged. The resulting precipitate was dispersed in toluene to obtain the lead sulfide quantum dots.

7. The method for fabricating a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor according to claim 6, characterized in that, The ratio of lead oxide, oleic acid and trimethylsilyl iodine added is 0.9 g: 3 mL: 420 μL.

8. The method for fabricating a high-resolution self-assembled dual quantum dot / graphene heterojunction broadband memristor according to claim 6, characterized in that, The heating conditions are: temperature 140℃, time 1 hour; The cooling temperature is 100°C; The continued reaction was carried out at a temperature of 100°C for 60 seconds.

9. A highly self-assembled dual quantum dot / graphene heterojunction broadband memristor prepared by the preparation method according to any one of claims 1-8.

10. An application of the ultra-high self-assembled dual quantum dot / graphene heterojunction broadband memristor as described in claim 9 in the fields of biomimetic vision, optical neural networks and intelligent sensing.

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