Wide-bandgap semiconductor perovskite heterojunction memristor and preparation method thereof

Abstract

The application relates to the technical field of memristor, in particular to a wide-bandgap semiconductor perovskite heterojunction memristor and a preparation method thereof. The memristor comprises, from bottom to top, a substrate, a wide-bandgap thin film layer, a perovskite thin film layer and a metal thin film electrode which are tightly stacked in sequence; the perovskite thin film layer and the wide-bandgap thin film layer form a heterojunction; the material of the perovskite thin film layer is quasi-two-dimensional metal halide perovskite. The wide-bandgap thin film layer is subjected to plasma surface modification, so that the adhesion and crystallization quality of the perovskite thin film layer are improved; the sol-gel method and the thermal evaporation method are adopted, so that excellent crystallization and gradual switching characteristics are achieved, the current level in the high-resistance state is reduced, and the voltage-current characteristics of the device are improved, and the power consumption is reduced. The heterojunction memristor has a large switching ratio, and has stable retention time and cycle performance.

Description

Technical Field

[0001] This invention relates to the field of memristor technology, and in particular to a wide-bandgap semiconductor perovskite heterojunction memristor and its fabrication method. Background Technology

[0002] Memristors, as one of the four basic circuit elements besides resistors, capacitors, and inductors, have attracted considerable attention. In particular, non-volatile memory devices have become promising candidates for next-generation information storage due to their fast write, read, and erase speeds, low power consumption, polymorphic storage, and high scalability. Currently, various semiconductor materials have been used to construct memristors, including silicon oxide, metal oxides, metal nitrides, metal sulfides, and organic electronic materials. Although each of these materials has its advantages, their fabrication processes are complex. Therefore, it is necessary to explore novel memristor materials.

[0003] Metal halide perovskites (MHPs) possess excellent semiconductor properties and also exhibit ion migration characteristics, a first discovery in perovskite solar cells, demonstrating the potential of MHP memristors. Currently, compared to three-dimensional MHPs, low-dimensional (zero to two-dimensional) MHPs exhibit superior stability and switching performance, thus warranting further research. The interface layer of the memristor device structure plays a crucial role in controlling defect concentration and influencing changes in resistance switching behavior.

[0004] Therefore, in order to solve the above-mentioned technical problems, it is urgent to develop a new type of heterojunction memristor with a large switching ratio and stable hold time and cycle performance. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a wide-bandgap semiconductor perovskite heterojunction memristor and its fabrication method.

[0006] The primary objective of this invention is to provide a wide-bandgap semiconductor perovskite heterojunction memristor, comprising, from bottom to top, a substrate, a wide-bandgap thin film layer, a perovskite thin film layer, and a metal thin film electrode stacked in sequence.

[0007] A heterojunction is formed between a perovskite thin film layer and a wide bandgap thin film layer;

[0008] The material of the perovskite thin film layer is a quasi-two-dimensional metal halide perovskite.

[0009] Preferably, the A-site of the quasi-two-dimensional metal halide perovskite adopts (CA / Cs). ＋ (CA / FA) ＋ (CA / MA) ＋ (BA / Cs) ＋ Or any of the organic cations; the B site of the perovskite is Pb2+ Sn 2+ Any of the following, the X-site of the perovskite is selected using (Cl / Br). - ,Br - (Br / I) - Any one of them.

[0010] Preferably, the organic cation is BA. ＋ or EA ＋ The thickness of the perovskite thin film layer is 30~80nm.

[0011] Preferably, the wide-bandgap semiconductor in the wide-bandgap thin film layer is AlN, GaN, or Al x Ga 1-x Any one of N, 0 < x < 1; the thickness of the wide bandgap thin film layer is 500~1000 nm.

[0012] Preferably, the metal electrode material of the metal thin film electrode is selected from either Au or Ag; the substrate is a sapphire substrate.

[0013] Preferably, the metal thin film electrode has an independent dot-like structure and is uniformly distributed on the surface of the perovskite thin film layer.

[0014] The second objective of this invention is to provide a method for fabricating a wide-bandgap semiconductor perovskite heterojunction memristor, specifically comprising the following steps:

[0015] S1. A wide bandgap thin film layer is prepared on a substrate using a metal-organic vapor deposition method;

[0016] S2. The wide bandgap thin film layer was ultrasonically cleaned with iso-deionized water, ethanol, propanol and ethanol for 8-15 minutes each, and then placed in plasma for 3-10 minutes for surface modification.

[0017] S3. Dissolve the halide in DMSO solution to prepare a quasi-two-dimensional perovskite precursor solution;

[0018] S4. Using spin coating, a quasi-two-dimensional perovskite precursor solution is spin-coated onto a wide bandgap thin film layer pretreated in step S2, and then annealed at 100~180℃ for 8~15 minutes to obtain a perovskite thin film layer.

[0019] S5. A metal electrode was prepared on the perovskite thin film by thermal evaporation at an evaporation rate of 0.5~1.5 Å / s to obtain a wide bandgap semiconductor perovskite heterojunction memristor.

[0020] Preferably, the spin coating speed in step S4 is 2500~3500 revolutions per second, and the spin coating time is 30~60 seconds.

[0021] Preferably, in step S4, the spin coating speed is 3000 revolutions per second and the spin coating time is 40 seconds; the annealing temperature is 150°C and the time is 10 minutes.

[0022] Preferably, the evaporation rate in step S5 is 1 Å / s.

[0023] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0024] The wide-bandgap semiconductor perovskite heterojunction memristor fabricated in this invention achieves excellent crystallinity and graded-switching characteristics, effectively reducing the current level under high resistance conditions, thereby improving the device's voltage-current characteristics and reducing power consumption. This memristor utilizes a heterojunction structure formed by a wide-bandgap thin film layer and a perovskite thin film layer, promoting perovskite crystallization and enhancing device stability and reliability. Simultaneously, plasma surface modification technology improves the adhesion and crystallinity quality of the perovskite thin film layer. The fabrication method of this invention is simple, low-cost, allows for flexible material selection, and is highly adaptable to various environments, making it significant for promoting the application of memristors in neuromorphic computing, non-volatile memory, and other fields. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a wide bandgap semiconductor perovskite heterojunction memristor provided in an embodiment of the present invention.

[0026] Figure 2 The voltage-current curves of a wide-bandgap semiconductor perovskite heterojunction memristor provided according to an embodiment of the present invention are shown.

[0027] Figure label:

[0028] 1. Substrate;

[0029] 2. Wide bandgap thin film layer;

[0030] 3. Perovskite thin film layer;

[0031] 4. Metal thin film electrode. Detailed Implementation

[0032] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0034] See Figure 1 The present invention provides a wide bandgap semiconductor perovskite heterojunction memristor, which includes, from bottom to top, a substrate 1, a wide bandgap thin film layer 2, a perovskite thin film layer 3 and a metal thin film electrode 4 stacked in sequence; wherein, the perovskite thin film layer 3 and the wide bandgap thin film layer 2 form a heterojunction.

[0035] Specifically, substrate 1 is a sapphire substrate;

[0036] The wide bandgap semiconductor in wide bandgap thin film layer 2 is made of AlN, GaN, or Al x Ga 1-x Any one of N (0 < x < 1); the thickness of the wide bandgap thin film layer 2 is 500~1000 nm; the wide bandgap thin film layer 2 is prepared on the substrate 1 by metal-organic vapor deposition (MOCVD);

[0037] The perovskite film layer 3 is a quasi-two-dimensional metal halide perovskite film; the A-sites of the perovskite in the perovskite film layer 3 adopt (CA / Cs). ＋ (CA / FA) ＋ (CA / MA) ＋ (BA / Cs) ＋ Or any one of the organic cations, wherein the organic cation is BA ＋ or EA ＋ The B site of the perovskite was obtained using Pb. 2+ Sn 2+ Any of the following, the X-site of the perovskite is selected using (Cl / Br). - ,Br - (Br / I) - Any one of the following; in a specific embodiment, the perovskite is BAPbBr4, EAPbBr4 or BA2CsPb2Br7;

[0038] The thickness of the perovskite thin film layer 3 is 30~80 nm; the perovskite thin film layer 3 is prepared on a wide bandgap film by a sol-gel method; the sol-gel method specifically includes: spin-coating a quasi-two-dimensional perovskite precursor solution using a spin coating method, with a spin coating speed of 2500~3500 rpm and a spin coating time of 30~60 seconds; then annealing at 100~180℃ for 8~15 minutes to ensure solvent evaporation and improve crystallinity; in a specific embodiment, the spin coating speed is 3000 rpm and the time is 40 seconds, and the annealing temperature is 150℃ and the time is 10 minutes;

[0039] The metal thin film electrode 4 is made of either Au or Ag, with Au being preferred in the specific embodiment. The metal thin film electrode 4 is prepared by thermal evaporation at a rate of 0.5 to 1.5 Å / s. The metal thin film electrode 4 has an independent dot-like structure and is uniformly distributed on the surface of the perovskite thin film layer 3.

[0040] When using a wide-bandgap semiconductor perovskite heterojunction memristor, the metal thin film electrode 4 is connected to the P electrode, while the wide-bandgap thin film layer 2 is connected to the N electrode, and the circuit is connected to a semiconductor analyzer for testing. Due to the presence of dangling bonds, the wide-bandgap thin film layer 2 promotes the crystallization of the perovskite thin film layer 3. In addition, the heterojunction structure formed by the perovskite thin film layer 3 and the wide-bandgap thin film layer 2 can effectively reduce the current level under high resistance conditions and improve the abrupt change behavior of the memristor's voltage-current characteristics.

[0041] It should be noted that the wide bandgap semiconductor perovskite heterojunction memristor and its fabrication method of the present invention overcome the problem of abrupt switching behavior of perovskite memristors and achieves gradual switching characteristics.

[0042] Example 1

[0043] This embodiment provides a method for fabricating a wide-bandgap semiconductor perovskite heterojunction memristor, specifically including the following steps:

[0044] S1. Select a sapphire substrate and use the MOCVD method to prepare a Si-doped GaN semiconductor thin film, i.e. a wide bandgap thin film layer;

[0045] S2. Pretreatment of wide bandgap thin film layer: The wide bandgap thin film layer was ultrasonically cleaned with iso-deionized water, ethanol, propanol and ethanol for 10 minutes each, and finally placed in plasma for 5 minutes for surface modification.

[0046] S3. Preparation of quasi-two-dimensional perovskite precursor solution: BABr, CsBr and PbBr2 were mixed and dissolved in DMSO solution at a mass ratio of 2:1:2, and the Pb concentration was kept at 0.4M to obtain quasi-two-dimensional metal halide perovskite BA2CsPb2Br7 precursor solution.

[0047] S4. Preparation of perovskite thin film layer: Quasi-two-dimensional perovskite precursor solution was spin-coated onto the pretreated wide bandgap thin film layer by spin coating at a speed of 3000 rpm for 40 seconds; then annealed at 150℃ for 10 minutes to form BA2CsPb2Br7 perovskite layer, i.e., perovskite thin film layer.

[0048] S5. Fabrication of metal thin film electrodes: Metal electrodes were fabricated on perovskite thin film layers by thermal evaporation at a rate of 1 Å / s to obtain heterojunction memristors.

[0049] The voltage and current curves provided in the embodiments of the present invention are as follows: Figure 2 As shown, the continuous switching characteristics and large switching ratio are evident.

[0050] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0051] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A wide-bandgap semiconductor perovskite heterojunction memristor, characterized in that: From bottom to top, the structure includes a substrate, a wide bandgap thin film layer, a perovskite thin film layer, and a metal thin film electrode, all stacked in sequence. The wide bandgap semiconductor in the wide bandgap thin film layer is made of AlN, GaN, or Al. x Ga 1-x Any of N, 0 < x < 1; wide bandgap thin film layers have dangling bonds; A heterojunction is formed between a perovskite thin film layer and a wide bandgap thin film layer; The perovskite thin film layer is made of quasi-two-dimensional metal halide perovskite; the A-site of the quasi-two-dimensional metal halide perovskite adopts (CA / Cs). ＋ (CA / FA) ＋ (CA / MA) ＋ (BA / Cs) ＋ Or any of the organic cations; the B site of the perovskite is Pb 2+ Sn 2+ Any of the following, the X-site of the perovskite is selected using (Cl / Br). - ,Br - (Br / I) - Any one of them; The perovskite thin film layer is obtained by spin coating a quasi-two-dimensional perovskite precursor solution onto a pretreated wide bandgap thin film layer, followed by annealing at 100~180℃ for 8~15 minutes. The wide bandgap thin film layer is prepared by metal-organic vapor deposition. The pretreatment process is as follows: the wide bandgap thin film layer is ultrasonically cleaned with deionized water, ethanol, propanol and ethanol for 8-15 minutes each, and then placed in plasma for 3-10 minutes for surface modification.

2. The wide bandgap semiconductor perovskite heterojunction memristor according to claim 1, characterized in that: The organic cation is BA. ＋ or EA ＋ The thickness of the perovskite thin film layer is 30~80nm.

3. The wide bandgap semiconductor perovskite heterojunction memristor according to claim 1, characterized in that: The thickness of the wide bandgap thin film layer is 500~1000nm.

4. The wide bandgap semiconductor perovskite heterojunction memristor according to claim 1, characterized in that: The metal electrode material of the metal thin film electrode is selected from either Au or Ag; the substrate is a sapphire substrate.

5. A wide bandgap semiconductor perovskite heterojunction memristor according to claim 4, characterized in that: The metal thin film electrode has an independent dot-like structure and is uniformly distributed on the surface of the perovskite thin film layer.

6. A method for fabricating a wide-bandgap semiconductor perovskite heterojunction memristor, used to fabricate the wide-bandgap semiconductor perovskite heterojunction memristor as described in claim 1, characterized in that: Specifically, the steps include the following: S1. A wide bandgap thin film layer is prepared on a substrate using a metal-organic vapor deposition method; S2. The wide bandgap thin film layer is ultrasonically cleaned with deionized water, ethanol, propanol and ethanol for 8-15 minutes each, and then placed in plasma for 3-10 minutes for surface modification. S3. Dissolve the halide in DMSO solution to prepare a quasi-two-dimensional perovskite precursor solution; S4. Using spin coating, a quasi-two-dimensional perovskite precursor solution is spin-coated onto a wide bandgap thin film layer pretreated in step S2, and then annealed at 100~180℃ for 8~15 minutes to obtain a perovskite thin film layer. S5. A metal electrode was prepared on the perovskite thin film by thermal evaporation at an evaporation rate of 0.5~1.5 Å / s to obtain a wide bandgap semiconductor perovskite heterojunction memristor.

7. The method for fabricating a wide-bandgap semiconductor perovskite heterojunction memristor according to claim 6, characterized in that: In step S4, the spin coating speed is 2500~3500 revolutions per second, and the spin coating time is 30~60 seconds.

8. The method for fabricating a wide-bandgap semiconductor perovskite heterojunction memristor according to claim 7, characterized in that: In step S4, the spin coating speed is 3000 revolutions per second and the spin coating time is 40 seconds; the annealing temperature is 150°C and the time is 10 minutes.

9. The method for fabricating a wide-bandgap semiconductor perovskite heterojunction memristor according to claim 6, characterized in that: The evaporation rate in step S5 is 1 Å / s.

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