Reconfigurable quantum dot storage and computing integrated device based on ion migration and preparation method thereof

Abstract

This invention relates to the field of interdisciplinary technology of semiconductor devices and quantum materials, and particularly to a reconfigurable quantum dot in-memory computing device based on ion migration and its fabrication method. By using HgTe colloidal quantum dots as the core material and doping with metal ions to modulate their semiconductor properties, the potential barrier is modulated using the reversible adsorption and desorption effects of metal ions on the surface of the colloidal quantum dots, as well as charge transfer between the metal ions and the quantum dots, thus replacing the traditional conductive filament mechanism. This resistive-state locking mechanism based on interfacial ion adsorption transforms the originally random ion migration process into a controllable ion flow, significantly reducing the cycle-to-cycle variability of the device and achieving highly consistent resistance transition characteristics. Subsequently, through interface engineering optimization, an in-memory computing device with excellent cycle durability and data retention capabilities is obtained, meeting the stringent hardware stability requirements of neural network computing.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices and quantum materials, and in particular to a reconfigurable quantum dot in-memory computing device based on ion migration and its fabrication method. Background Technology

[0002] As integrated circuit manufacturing processes continue to shrink, Moore's Law is gradually approaching its physical limits, ushering in the "post-Moore's Law era" for the semiconductor industry. The traditional von Neumann architecture's separation of storage and computing units leads to frequent data transfers between the two, causing severe "memory walls" and "power walls." Faced with the explosive growth in data processing demands in the era of artificial intelligence and big data, there is an urgent need to develop emerging hardware with in-memory computing capabilities to cope with the dual pressures of storage and processing brought about by massive amounts of data.

[0003] Among the many emerging resistive switching materials, colloidal quantum dots (CQDs) are considered ideal candidates for replacing traditional inorganic metal oxide resistive switching materials and building next-generation high-performance memristors due to their advantages such as low-temperature solution processing, easy bandgap tuning, rich surface chemical properties, and good compatibility with CMOS (complementary metal oxide semiconductor) technology.

[0004] However, despite some progress in the research of colloidal quantum dot memristors, existing CQD memristor technology still has significant limitations, making it difficult to meet the high standards required for neural network training and inference in practical applications. The specific shortcomings are mainly reflected in the following aspects:

[0005] 1. Uncontrollable ion migration mechanism: The ion migration paths within existing devices are often highly random, making it difficult to precisely control the formation and breakage of conductive filaments. This randomness directly leads to severe dispersion in the device's resistance parameters, affecting the device's consistency.

[0006] 2. Insufficient durability and stability: Due to the lack of effective constraint on ion migration channels, the active layer material is prone to structural degradation under repeated electric fields. Currently reported colloidal quantum dot memristors generally exhibit poor cycle durability, making it difficult to support high-intensity computational tasks.

[0007] 3. Power consumption and linearity issues: Existing devices typically have high operating voltages and low linearity during resistor adjustment, which is not conducive to achieving low-power, high-precision analog synaptic weight updates.

[0008] To achieve high-performance in-memory computing devices (i.e., memristors), it is essential to start from the microscopic mechanism by introducing reversible and controllable ion coordination sites on the surface of quantum dots. This allows for the directional guidance of ion flow and precise control of the resistive state based on interfacial ion adsorption effects. However, the industry currently lacks effective strategies for precisely controlling the ion migration rate, path, and residence time within CQDs through the synergistic design of metal ion doping and surface ligands. Furthermore, reports on constructing multifunctional integrated devices capable of simultaneously performing electrical sensing, resistive switching storage, and synaptic computing using such modified materials are extremely rare.

[0009] Therefore, there is an urgent need to develop a new method for modifying quantum dot materials and a new device structure to solve the above-mentioned technical bottlenecks. Summary of the Invention

[0010] Based on the above problems, this invention addresses the shortcomings of existing quantum dot memristor devices in terms of resistive state stability, doping controllability, and interface compatibility. This invention discloses a method for fabricating reconfigurable quantum dot in-memory computing devices based on ion migration, and proposes a technical solution that uses HgTe colloidal quantum dots as the core material, modulates their semiconductor properties through metal ion doping, and combines interface engineering optimization.

[0011] To achieve the above objectives, the first technical solution of this application discloses a method for fabricating a reconfigurable quantum dot in-memory computing device based on ion migration, comprising sequentially stacking a substrate layer, a bottom electrode layer, an active layer, and a top electrode layer, wherein the active layer is obtained through the following steps:

[0012] S1. Preparation of colloidal quantum dots based on mercury telluride

[0013] Under vacuum conditions, a TOP-Te precursor solution was injected into an OA-Hg precursor solution to obtain HgTe quantum dots. After the reaction was completed, a pre-cooled quenching solution was injected to terminate the reaction and a coolant was obtained. A ligand modification solution was added to the coolant, and the precipitate obtained after centrifugation was purified to obtain colloidal quantum dots based on mercuric telluride.

[0014] S2. Spin-coating a film of colloidal quantum dots based on mercury telluride;

[0015] S3. Functionally doping the spin-coated colloidal quantum dots of mercury telluride to obtain an active layer.

[0016] Furthermore, in step S1, before injecting the OA-Te precursor solution, the temperature of the OA-Hg precursor solution is maintained at 70~80℃.

[0017] Furthermore, the reaction time described in S1 is 4-5 minutes.

[0018] Furthermore, the HgTe quantum dots obtained in S1 have a particle size of 4~5 nm.

[0019] Furthermore, the preparation method of the quenching solution in S1 is as follows: trioctylphosphine, dodecanethiol and tetrachloroethylene are mixed and shaken and then stored at -20°C, wherein the volume ratio of trioctylphosphine, dodecanethiol and tetrachloroethylene is 1:3:12.

[0020] Furthermore, the ligand modification solution described in S2 is a dodecyl dimethyl ammonium bromide solution.

[0021] Furthermore, after spin-coating the colloidal quantum dots based on mercury telluride into a film, as described in S2, a mixed solution of 1,2-ethylenedithiol, hydrochloric acid, and isopropanol is dropped onto the film surface for ligand exchange, and the spin-coating-exchange step is repeated 3-5 times.

[0022] Furthermore, the functional doping treatment described in S3 includes:

[0023] ①P-type doping: The thin film after spin-coating of mercury telluride-based colloidal quantum dots was treated with HgCl2 solution;

[0024] ② Environmental optimization: After treatment in step ①, solid-phase ligand exchange was performed using a mixed solution of HCl:EDT:IPA;

[0025] ③ Metal ion doping: After step ②, spin-coating a layer of inorganic metal salt solution with a concentration of 1 mMol / mL yields a colloidal quantum dot active layer of mercury telluride based on metal ion doping.

[0026] Furthermore, it also includes self-assembly modification by dripping MPTS onto the surfaces of the substrate and bottom electrode layer.

[0027] And, the ion migration-based reconfigurable quantum dot in-memory computing device prepared according to any of the above preparation methods.

[0028] Beneficial effects:

[0029] 1. Existing colloidal quantum dot memristors (in-memory computing devices) typically rely on internal material defects or metal electrode diffusion to achieve resistance switching, resulting in random and uncontrollable formation paths for the conductive filaments. This invention introduces metal ion doping into the active layer of HgTe quantum dots. Metal ions, as highly active mobile ion sources, can migrate directionally along grain boundaries or ligand channels under the influence of an electric field. This directional doping effectively constrains the growth path of the conductive filaments, transforming the originally random ion migration process into a controllable ion flow, significantly reducing the cycle-to-cycle variability of the device, and achieving highly consistent resistance switching characteristics.

[0030] 2. Synergistic effect of solid-state ligand exchange and p-type doping significantly improves carrier transport efficiency: In applications, a specific solid-state ligand exchange process (1,2-ethylenedithiol:hydrochloric acid:isopropanol system) combined with HgCl2 (p-type doping) was used to deeply optimize the quantum dot surface environment. This process effectively replaces long-chain insulating ligands (such as oleylamine) that hinder electron transport, not only shortening the physical distance between quantum dots (transforming from an insulating state to a conductive coupled state), but also passivating surface defect traps through the introduction of Cl⁻ ions. This synergistic treatment greatly reduces the charge transport barrier, enabling the device to achieve stable resistive switching at a lower operating voltage, solving the problems of high power consumption and low on / off ratio of traditional devices.

[0031] 3. The combination of interface chemical modification and inert electrodes overcomes the device's durability bottleneck: Addressing the problem of weak adhesion and easy detachment of colloidal quantum dot films at the electrode interface, leading to short lifespan, this invention constructs a robust "sandwich" structure. A self-assembled trimethoxysilane (MPTS) molecular layer is introduced onto the surface of the ITO bottom electrode, utilizing the "molecular bridge" effect of the silane coupling agent to lock the quantum dot layer. Simultaneously, chemically inert gold (Au) is selected as the top electrode, avoiding material loss during repeated oxidation-reduction processes. This structural design effectively prevents mechanical stripping and chemical degradation of the active layer during repeated erase and write operations, significantly improving the device's cycle endurance and data retention capabilities, thus meeting the stringent hardware stability requirements of neural network computing. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a process flow diagram for the fabrication of HgTe colloidal quantum dot in-memory computing devices;

[0034] Figure 2 This is a schematic diagram of the fabrication process and layered structure of a metal-doped HgTe colloidal quantum dot in-memory computing device;

[0035] Figure 3 This is a diagram of an in-memory computing device array, where (a) is a three-dimensional structural schematic diagram of the in-memory computing device array; and (b) is a top-view microscopic view of the actual fabricated device (depicted with black and white lines).

[0036] Figure 4 These are the results of the cycle durability test of the HgTe colloidal quantum dot in-memory computing device;

[0037] Figure 5 These are the test results of the data retention capability of HgTe colloidal quantum dot in-memory computing devices. Detailed Implementation

[0038] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] The first embodiment of this application discloses a method for fabricating a reconfigurable quantum dot in-memory computing device based on ion migration, as shown in Figure 1. Figure 1 As shown, it includes a substrate layer, a bottom electrode layer, an active layer, and a top electrode layer stacked sequentially, wherein the active layer is obtained through the following steps:

[0040] S1. Preparation of colloidal quantum dots based on mercury telluride

[0041] Under vacuum conditions, a TOP-Te precursor solution was injected into an OA-Hg precursor solution to obtain HgTe quantum dots. The reaction was then terminated by injecting a pre-cooled quenching solution to obtain a coolant. A ligand modification solution was added to the coolant, and the precipitate obtained after centrifugation was purified to obtain colloidal quantum dots based on mercuric telluride.

[0042] In this embodiment, the entire reaction is carried out in a vacuum environment with oxygen and water content both <0.1 ppm, such as a vacuum glove box system. This technique can solve the problems of easy oxidation of HgTe materials and insufficient compatibility with CMOS processes. This invention, through a rigorous oxygen- and anhydrous (<0.1 ppm) end-to-end fabrication process, combined with low-temperature curing (<150°C) and an inert gold (Au) top electrode design, effectively prevents the oxidative degradation and cross-contamination of active materials, achieving stable fabrication of high-performance devices at low temperatures, meeting the requirements for integration with silicon-based microelectronic processes. It overcomes the defect of HgTe's extreme oxidizability, obtaining high-quality quantum dot materials with uniform particle size (~4.5 nm) and excellent monodispersity, ensuring the uniformity of device performance from the source.

[0043] In this embodiment, the OA-Hg precursor solution is an oleylamine (OAm) solution of mercuric chloride (HgCl2) with a concentration of 0.02 mmol / mL; the TOP-Te precursor solution is a trioctylphosphine (Top) solution of tellurium (Te) with a concentration of 1 mmol / mL.

[0044] In this embodiment, before injecting the OA-Te precursor solution, the temperature of the Hg precursor solution is maintained at 70~80°C, and then the TOP-Te precursor solution is rapidly injected, with a reaction time of 4~5 min. By injecting at low temperature (70°C), the nucleation and growth rates can be balanced to obtain HgTe quantum dots with a target particle size of approximately 4.5 nm.

[0045] In this embodiment, the purpose of adding the quenching solution after the S1 reaction is completed is to quickly terminate the reaction and prevent the HgTe quantum dots from continuing to grow and aggregate. The quenching solution is prepared by mixing and shaking trioctylphosphine, dodecanethiol and tetrachloroethylene and storing it at -20°C. The volume ratio of trioctylphosphine, dodecanethiol and tetrachloroethylene is 1:3:12.

[0046] In this embodiment, the purpose of centrifugation is to separate HgTe quantum dots (solid) and liquid. Preferably, after centrifugation at 6000 rpm for 3 minutes, the supernatant is discarded and the precipitate is retained. The precipitate is HgTe quantum dots.

[0047] It should be noted that in this step, a ligand modification solution (DDAB, bis(dodecyl dimethyl)ammonium bromide solution) needs to be added to the cooling liquid before centrifugation. The purpose is to promote the phase transfer of HgTe quantum dots from the nonpolar solvent to the polar solvent, thereby accelerating the centrifugal separation.

[0048] The above preparation method involves 1. directly introducing metal ions (such as K⁺) doping into the quantum dot active layer, and combining it with p-type doping (HgCl2) and surface ligand regulation to construct controllable ion migration channels inside the material, thereby restricting the disordered diffusion of ions and significantly improving the repeatability of memristor resistance switching, cycle durability and consistency of high / low resistance states.

[0049] In this embodiment, the centrifugation is followed by a washing and purification step to obtain purified mercury telluride-based colloidal quantum dots. The purification step preferably involves adding 2 mL of chlorobenzene to the precipitate for dissolution, followed by re-precipitation and washing. This "dissolution-precipitation" step is repeated three times to thoroughly remove residual ligands. Finally, 2 mL of chlorobenzene is added to dissolve the precipitate, which is then filtered through a syringe filter into a brown reagent bottle and stored under sealed conditions at low temperature.

[0050] like Figure 2As shown, a typical in-memory computing device (i.e., a memristor) includes a bottom electrode, an active layer, and a top electrode. The active layer functions as a means for the HgTe colloidal quantum dot layer to reversibly modulate the potential barrier under an electric field through charge transfer or ion migration between the adsorbed metal ions and the quantum dots, thereby achieving multi-level resistive switching storage. In this application, a colloidal quantum dot based on mercury telluride is used as the active layer. The directionally doped metal ions act as a highly active mobile electron source, which can migrate directionally along grain boundaries or ligand channels under the action of an electric field, serving as the "core" and "guide" for the growth of conductive filaments. This directional doping effectively constrains the growth path of the conductive filaments, transforming the originally random ion migration process into a controllable ion flow, significantly reducing the cycle-to-cycle variation of the device, and achieving highly consistent resistance switching characteristics.

[0051] S2. Spin-coating a film with colloidal quantum dots based on mercury telluride: Specifically, spin-coating a film with colloidal quantum dots based on mercury telluride, then adding a mixed solution of 1,2-ethanedithiol, hydrochloric acid and isopropanol to the film surface for ligand exchange, and repeating the spin-coating-exchange step 3-5 times.

[0052] S3. Functionally doping the spin-coated colloidal quantum dots of mercury telluride to obtain the active layer:

[0053] ①P-type doping: The active layer of the colloidal quantum dot based on mercury telluride was treated with HgCl2 solution;

[0054] ② Environmental optimization: After treatment in step ①, solid-phase ligand exchange was performed using a mixed solution of HCl:EDT:IPA;

[0055] ③ Metal ion doping: After step ②, spin-coating a layer of inorganic metal salt solution with a concentration of 1 mMol / mL yields a colloidal quantum dot active layer of mercury telluride based on metal ion doping.

[0056] The purpose of introducing a mixed solution of 1,2-ethanedithiol, hydrochloric acid, and isopropanol in this embodiment is to address the problem of ligands on the quantum dot film surface hindering charge carrier transport and causing poor device uniformity. The addition of the mixed solution effectively removes long-chain insulating ligands (such as oleylamine), precisely adjusts the charge carrier concentration and trap state density, and achieves uniform and controllable thickness and electrical properties of the quantum dot film, ensuring large-area consistency of the device array. This not only shortens the physical distance between quantum dots (transforming them from insulating to conductive coupled states) but also passivates surface defect traps through the introduction of Cl⁻ ions. This synergistic treatment significantly reduces the charge transport barrier, enabling the device to achieve stable resistive switching at lower operating voltages, solving the problems of high power consumption and low on / off ratio in traditional devices.

[0057] In a further embodiment, the device undergoes self-assembly modification by adding MPTS to the substrate and bottom electrode layer. This aims to address the poor adhesion and easy peeling of the colloidal quantum dot film at the inorganic electrode interface. By introducing a silane coupling agent (MPTS) between the ITO bottom electrode and the quantum dot layer, the interface is modified, utilizing its molecular bridging effect to enhance the adhesion of the organic-inorganic interface. This solves the problems of difficult film formation, poor contact, and physical peeling during long-term use, thereby improving the mechanical stability of the device. A trimethoxysilane (MPTS) self-assembled molecular layer is introduced onto the surface of the ITO bottom electrode, using the "molecular bridge" effect of the silane coupling agent to lock the quantum dot layer. Simultaneously, chemically inert gold (Au) is selected as the top electrode to avoid material loss during repeated oxidation-reduction processes. This structural design effectively prevents mechanical peeling and chemical degradation of the active layer during repeated erase and write processes, significantly improving the device's cycle endurance and data retention capabilities, thus meeting the stringent hardware stability requirements of neural network computing.

[0058] The technical solution and technical effects of this application will be further explained below through specific embodiments.

[0059] Example 1: Fabrication of a reconfigurable quantum dot in-memory computing device based on ion migration

[0060] 1. Preparation of active layer

[0061] S1. Preparation of colloidal quantum dots based on mercury telluride

[0062] (1) Preparation of precursor and auxiliary solution

[0063] This part of the process aims to obtain quantum dot materials with good monodispersity and controllable particle size. The entire process is carried out in a vacuum glove box system where oxygen and water content are controlled to <0.1 ppm. The specific process is as follows: Figure 1 As shown, the detailed steps are as follows:

[0064] ① Preparation of quenching solution: Add 1 mL of trioctylphosphine (TOP, a strong coordinating solvent), 3 mL of dodecanethiol (DDT, which provides thiol groups) and 12 mL of tetrachloroethylene (TCE, a high-boiling-point solvent) to a 20 mL container, mix and shake for 10 seconds, and then store at -20°C. This solution is used to quickly terminate growth and prevent aggregation.

[0065] ② Preparation of ligand-modified solution (DDAB): Weigh 1.5 g of bis(dodecyl)dimethylammonium bromide (DDAB, purity ≥98%), add isopropanol (IPA) and bring the volume to 40 mL. Stir magnetically (500 rpm, 30 min) and sonicate (40 kHz, 10 min) until clear.

[0066] ③ Preparation of Hg precursor: Weigh 0.4 mmol (108.8 mg) of mercuric chloride (HgCl2) powder and add 12 mL of oleylamine (OAm) as ligand and solvent. Heat and stir at 110°C and 1500 rpm for 1 hour to activate the precursor; then cool to 70°C and hold at that temperature for 30 minutes to allow the system to reach thermal equilibrium.

[0067] (2) The hot-injection growth and reaction were controlled in a glove box. When the Hg precursor solution was stable at 70°C, 400 μL of TOP-Te solution (tellurium precursor) was rapidly injected. The reaction time was strictly controlled to 4 minutes. By balancing the nucleation and growth rate through low-temperature injection, HgTe quantum dots with a target particle size of about 4.5 nm were obtained.

[0068] (3) Reaction quenching and purification

[0069] 1. Termination of reaction: After 4 minutes of reaction, immediately inject pre-cooled quenching solution to terminate the reaction, and remove the reaction solution from the glove box and cool it to room temperature in a water bath.

[0070] 2. Centrifugation: Divide the cooling liquid into centrifuge tubes, add 2 mL of DDAB solution and bring the volume to 50 mL with isopropanol. Shake well and centrifuge at 6000 rpm for 3 minutes. Discard the supernatant and keep the precipitate.

[0071] (4) Add 2 mL of chlorobenzene to the precipitate to dissolve it, and wash the precipitate again. Repeat the "dissolve-precipitate" step three times to completely remove residual ligands. Finally, add 2 mL of chlorobenzene to dissolve the precipitate, filter it through a syringe filter into a brown reagent bottle, and store it in a sealed container at low temperature.

[0072] S2. Spin coating for film formation

[0073] The quantum dot active layer was deposited layer by layer using a multi-step spin-coating method. A single cycle operation is as follows:

[0074] (1) Spin-coating quantum dots: Take 60 μL of the prepared HgTe quantum dot solution and add it to the substrate, then spin-coat at 2500 rpm for 20 seconds.

[0075] (2) Solid phase ligand exchange: A mixed solution with a volume ratio of Edt:HCl:IPA = 1:1:50 was dropped onto the membrane surface and allowed to stand for 10 seconds to perform ligand exchange (removal of long chain ligands). Then, the membrane was spin-coated and dried, and rinsed with isopropanol and dried.

[0076] (3) Cyclic deposition: Repeat the above "spin-coating-exchange" steps 3 to 5 times (preferably 3 times) to form a quantum dot film with uniform thickness (50-100 nm).

[0077] S3. Functionalization doping treatment

[0078] The following processes were performed sequentially on the deposited quantum dot film:

[0079] (1) P-type doping: HgCl2 solution is introduced to treat the thin film and the carrier concentration is adjusted.

[0080] (2) Environmental optimization: Solid-phase ligand exchange was performed again using a mixed solution of HCl:EDT:IPA to optimize the surface chemical environment.

[0081] (3) Metal ion doping: Spin-coating a layer of inorganic metal salt solution with a concentration of 1 mMol / mL to introduce metal ion doping and complete the preparation of the active layer.

[0082] 2. Quantum dot in-memory computing devices

[0083] This part of the process utilizes the aforementioned active layer to fabricate a memristor with a "bottom electrode / active layer / top electrode" structure. The fabrication process is as follows: Figure 1 As shown, the layered structure is as follows Figure 2 As shown, the specific steps are as follows:

[0084] S1. Substrate material pretreatment and surface finishing

[0085] 1. Cleaning: Indium tin oxide (ITO) glass is selected as the conductive substrate, and the surface is cleaned with an air gun to remove dust and impurities.

[0086] 2. MPTS modification: Add an appropriate amount of trimethoxysilane (MPTS) solution to the ITO surface, let it stand for 30 seconds to perform self-assembly modification to enhance the interfacial bonding force, and then rinse with isopropanol and evaporate to dryness.

[0087] S2. Stack the active layer on the substrate material modified according to the active layer preparation method in step 1.

[0088] S3. Thermal Evaporation of Top Electrode

[0089] (1) Mask: Fix the sample onto the mask template. The pattern is designed as an intersection structure orthogonal to the bottom electrode.

[0090] (2) Evaporation: Place the coating in a thermal evaporation coating machine and select gold (Au) as the top electrode material. Start the vacuum pump and begin evaporation after the vacuum level reaches the standard, controlling the evaporation rate to be 0.5~0.6 Å / s.

[0091] (3) Molding: When the gold electrode deposition thickness reaches 500 Å, stop heating and remove the sample after natural cooling.

[0092] like Figure 3 (a) and Figure 3 As shown in (b), the in-memory computing device prepared by the present invention has a typical cross-point array structure, and its vertical structure from bottom to top includes:

[0093] 1. Substrate and bottom electrode layer (ITO): Transparent conductive glass modified with MPTS, serving as physical support and initial conductive path.

[0094] 2. Active layer (HgTe:Metal Ions): Located above the bottom electrode, with a thickness of 50-100 nm. This layer is composed of a HgTe colloidal quantum dot film that has undergone metal ion doping and ligand exchange treatment, utilizing the migration of metal ions and the charge capture / release mechanism of quantum dots to achieve reversible switching of the resistance state.

[0095] 3. Top electrode layer (Au): Located above the active layer, with a thickness of approximately 50 nm. The Au electrode has excellent chemical inertness, ensuring high stability and long cycle life of the device during repeated erase and write processes.

[0096] Experimental Example 1: Performance Analysis of In-Memory Computing Devices

[0097] Cyclic Endurance: This invention evaluates the stability of the device under repeated switching operations through a cyclic endurance test. During the test, write pulses (Set Pulse) and erase pulses (Reset Pulse) are alternately applied to the device to drive the adsorption and desorption of metal ions on the colloidal quantum dot surface, thereby forcing the device to cycle between a low-resistance state (LRS) and a high-resistance state (HRS). After each pulse operation, a low-magnitude read signal (e.g., a 0.1 V read pulse) is applied to detect the current resistance state, thereby avoiding unintended disturbances to the device state. Figure 4 As shown, under electrical excitation with an amplitude of ±0.5 V and a pulse width of 10 μs, the device exhibits significant resistive-state switching characteristics: its low-resistive-state current is approximately 9 μA, and its high-resistive-state current is approximately 4 μA. Experimental results show that after 10 μA... 6 After several consecutive pulse cycles, the high and low resistance current values ​​and the on / off ratio did not show significant drift, and the physical performance remained highly consistent. This demonstrates that the quantum dot memristor based on the ion adsorption mechanism can effectively suppress resistance failure caused by material fatigue during repeated cycling, exhibiting excellent cycle durability.

[0098] Data Retention Capability: This invention evaluates the persistence of information stored by a device under power-off conditions through a data retention capability test. During the test, a write or erase pulse is first applied to bring the device to a preset low-resistance state (LRS) or high-resistance state (HRS). Then, with the excitation signal removed, a weak read voltage (e.g., 0.1 V) is applied at preset time intervals, and the change in device current over time is monitored. Experimental results are as follows: Figure 5 As shown, under room temperature conditions, the high and low resistance current values ​​of the device are up to 10 4The device maintains high stability within a monitoring period of seconds, without any obvious resistance state reversion or overlap. This excellent retention characteristic is attributed to the synergistic design of the colloidal quantum dot surface in this embodiment: by precisely controlling the coordination strength between surface ligands and dopant ions, the energy barrier for ion desorption is increased. Compared to the traditional conductive filament mechanism, which is susceptible to thermal disturbances, the resistance state locking mechanism based on the adsorption effect of the quantum dot surface in this invention significantly enhances the reliability of information storage, demonstrating its great potential as a non-volatile in-memory computing unit.

[0099] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for fabricating a reconfigurable quantum dot in-memory computing device based on ion migration, comprising sequentially stacking a substrate layer, a bottom electrode layer, an active layer, and a top electrode layer, characterized in that, The active layer is obtained through the following steps: S1. Preparation of colloidal quantum dots based on mercury telluride Under vacuum conditions, a TOP-Te precursor solution is injected into an OA-Hg precursor solution. After HgTe quantum dots are obtained by the reaction, a pre-cooled quenching solution is injected to terminate the reaction and a coolant is obtained. Ligand modification solution was added to the coolant, and the precipitate obtained after centrifugation was purified to obtain colloidal quantum dots based on mercuric telluride; S2. Spin-coating a film of colloidal quantum dots based on mercury telluride; S3. Functionally doping the spin-coated colloidal quantum dots of mercury telluride to obtain an active layer.

2. The preparation method according to claim 1, characterized in that, In step S1, before injecting the OA-Te precursor solution, the temperature of the OA-Hg precursor solution is maintained at 70~80℃.

3. The preparation method according to claim 2, characterized in that, The reaction time described in S1 is 4-5 minutes.

4. The preparation method according to claim 2, characterized in that, The HgTe quantum dots obtained in S1 have a particle size of 4~5 nm.

5. The preparation method according to claim 2, characterized in that, The quenching solution described in S1 is prepared by mixing and shaking trioctylphosphine, dodecanethiol, and tetrachloroethylene and storing it at -20°C, wherein the volume ratio of trioctylphosphine, dodecanethiol, and tetrachloroethylene is 1:3:

12.

6. The preparation method according to claim 1, characterized in that, The ligand modification solution described in S2 is a dodecyl dimethyl ammonium bromide solution.

7. The preparation method according to claim 1, characterized in that, S2 describes the process of spin-coating a colloidal quantum dot based on mercury telluride into a film, followed by adding a mixed solution of 1,2-ethanedithiol, hydrochloric acid, and isopropanol to the film surface for ligand exchange, and repeating the spin-coating-exchange step 3-5 times.

8. The preparation method according to claim 1, characterized in that, The functional doping treatment described in S3 includes: ①P-type doping: The thin film after spin-coating of mercury telluride-based colloidal quantum dots was treated with HgCl2 solution; ② Environmental optimization: After treatment in step ①, solid-phase ligand exchange was performed using a mixed solution of HCl:EDT:IPA; ③ Metal ion doping: After step ②, spin-coating a layer of inorganic metal salt solution with a concentration of 1 mMol / mL yields a colloidal quantum dot active layer of mercury telluride based on metal ion doping.

9. The preparation method according to claim 1, characterized in that, It also includes self-assembly modification by dripping MPTS onto the surfaces of the substrate and bottom electrode layer.

10. A reconfigurable quantum dot in-memory computing device based on ion migration, prepared by any one of the preparation methods according to claims 1-9.

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