In-plane domain multi-angle overturning photoelectric ferroelectric device and preparation method thereof

Abstract

The invention discloses an in-plane domain multi-angle turnover photoelectric ferroelectric device and a preparation method thereof, and belongs to the technical field of microelectronic materials and devices. The structure of the in-plane domain multi-angle overturning photoelectric ferroelectric device comprises an insulating substrate, an inert metal electrode of a planar eight-claw structure and a two-dimensional ferroelectric layer which are combined in sequence, or the insulating substrate, the two-dimensional ferroelectric layer and the inert metal electrode of the planar eight-claw structure which are combined in sequence; the intersection of the inert metal electrode with the planar eight-claw structure is in contact with the two-dimensional ferroelectric layer; the material of the two-dimensional ferroelectric layer is two-dimensional alpha-In2Se3. According to the in-plane domain multi-angle overturning photoelectric ferroelectric device provided by the invention, the in-plane domain multi-angle overturning of the two-dimensional material can be realized to induce ferroelectric polarization, and a new research idea is provided for understanding other ferroelectric materials with in-plane ferroelectric domains.

Description

Technical Field

[0001] The present invention belongs to the technical field of microelectronic materials and devices, and particularly relates to an in-plane domain multi-angle flipping optoelectronic ferroelectric device and a preparation method thereof. Background Art

[0002] As a typical two-dimensional van der Waals ferroelectric material, α-In2Se3 has great potential for applications in optoelectronic devices, memory devices, sensors, and detectors. Current research indicates that α-In2Se3 exhibits ferroelectric polarization associated with both in-plane and out-of-plane domains. However, compared with the reported ferroelectric polarization induced by up-and-down flipping of out-of-plane domains, the ferroelectric polarization induced by multi-angle flipping of in-plane domains has not been experimentally explored. Summary of the Invention

[0003] The purpose of the present invention is to provide an optoelectronic ferroelectric device with multi-angle flipping of in-plane domains and a preparation method thereof. A planar octagonal electrode structure was designed by a maskless photolithography method, and a planar octagonal ferroelectric device based on two-dimensional α-In2Se3 was prepared to realize multi-angle flipping of in-plane domains of two-dimensional materials to induce ferroelectric polarization. With the help of optoelectronic coordinated control, it is proved that this structure can realize multi-angle flipping of in-plane domains to induce ferroelectric polarization. The present invention can provide a new research idea for understanding other ferroelectric materials with in-plane ferroelectric domains. Since the optoelectronic ferroelectric device with multi-angle flipping of in-plane domains in the present invention has the characteristics of multipolarization states, it can realize multi-bit storage, greatly improve the storage density, and meet the needs of massive information storage in the big data era.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] One of the technical solutions of the present invention: provides an optoelectronic ferroelectric device with multi-angle in-plane domain flipping, the structure of which includes an insulating substrate, an inert metal electrode with a planar octagonal structure and a two-dimensional ferroelectric layer combined in sequence, or an insulating substrate, a two-dimensional ferroelectric layer and an inert metal electrode with a planar octagonal structure combined in sequence; the intersection of the inert metal electrode with a planar octagonal structure is in contact with the two-dimensional ferroelectric layer; the material of the two-dimensional ferroelectric layer is two-dimensional α-In2Se3.

[0006] Optionally, the insulating substrate is made of SiO2.

[0007] Optionally, the inert metal is gold.

[0008] Preferably, the thickness of the planar octagonal structured inert metal electrode is 15 to 25 nm.

[0009] Preferably, the thickness of the two-dimensional α-In2Se3 is 35 to 45 nm.

[0010] The second technical solution of the present invention is to provide a method for preparing the above-mentioned optoelectronic ferroelectric device with multi-angle inversion of in-plane domains:

[0011] When the in-plane domain multi-angle flipping optoelectronic ferroelectric device structure comprises an insulating substrate, an inert metal electrode with a planar octagonal structure, and a two-dimensional ferroelectric layer that are sequentially combined, the preparation steps include:

[0012] A planar octagonal inert metal electrode is generated on an insulating substrate using a mask method, and then a two-dimensional α-In2Se3 is transferred to the planar octagonal inert metal electrode, where the intersection of the planar octagonal inert metal electrode contacts the two-dimensional ferroelectric layer, thereby obtaining the optoelectronic ferroelectric device with multi-angle inversion of the in-plane domains;

[0013] When the in-plane domain multi-angle flipping optoelectronic ferroelectric device structure comprises an insulating substrate, a two-dimensional ferroelectric layer, and an inert metal electrode with a planar octagonal structure that are sequentially combined, the preparation steps include:

[0014] First, the two-dimensional α-In2Se3 is transferred to an insulating substrate, and a planar octagonal structured inert metal electrode is generated on one side of the insulating substrate where the two-dimensional α-In2Se3 is transferred using a mask method. The intersection of the planar octagonal structured inert metal electrode contacts the two-dimensional ferroelectric layer to obtain the optoelectronic ferroelectric device with multi-angle in-plane domain flipping.

[0015] The color of the two-dimensional α-In2Se3 obtained by mechanical exfoliation in the present invention is observed through an optical microscope. Combined with the previously measured AFM data and the color correspondence, the two-dimensional nanosheets of corresponding thickness can be found.

[0016] Preferably, the inert metal electrode is deposited by thermal evaporation.

[0017] The beneficial technical effects of the present invention are as follows:

[0018] The present invention designs a planar octagonal inert metal electrode on an insulating substrate and then transfers a two-dimensional ferroelectric layer onto the inert metal electrode to produce an optoelectronic ferroelectric device with multi-angle in-plane domain flipping. The provided optoelectronic ferroelectric device with multi-angle in-plane domain flipping can achieve multi-angle in-plane domain flipping in two-dimensional materials to induce ferroelectric polarization, providing a new research approach for understanding other ferroelectric materials with in-plane ferroelectric domains.

[0019] From the results of obtaining light responses in different directions by applying the same external electric field in different directions of the photoelectric ferroelectric device with multi-angle in-plane domain flipping, it can be seen that the photoelectric ferroelectric device with multi-angle in-plane domain flipping of the present invention can generate in-plane ferroelectric domains with different polarization intensities in different directions. Due to its material properties, it is easy to polarize in a certain direction, that is, there is an easy polarization axis. The polarization intensity is strongest in the direction close to the easy polarization axis of the material, and it can be seen from the light response results in different directions that the polarization of the device in various directions affects each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of preparing an optoelectronic ferroelectric device with multi-angle in-plane domain flipping according to Example 1 of the present invention.

[0021] Figure 2 This is a schematic structural diagram of the optoelectronic ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1; wherein, 1: insulating substrate; 2: inert metal electrode; 3: two-dimensional ferroelectric material layer.

[0022] Figure 3 This is a current-time curve of the optoelectronic ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 after being pretreated with +4V in the 0°-180° direction and then applying an ultraviolet light pulse.

[0023] Figure 4 This is a current-time curve of the optoelectronic ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 after being pretreated at -4V in the 0°-180° direction and then applying an ultraviolet light pulse.

[0024] Figure 5 This is a current-time curve of the photoelectric ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 in the 45°-225° direction after being pre-treated with +4V and then applying an ultraviolet light pulse.

[0025] Figure 6 This is a current-time curve of the optoelectronic ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 in the 45°-225° direction after being pretreated at -4V and then applying an ultraviolet light pulse.

[0026] Figure 7 This is a current-time curve of the optoelectronic ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 after being pretreated at -4V in the 90°-270° direction and then applying an ultraviolet light pulse.

[0027] Figure 8 This is a current-time curve of the photoelectric ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 in the 90°-270° direction after being pre-treated with +4V and then applying an ultraviolet light pulse.

[0028] Figure 9This is a current-time curve of the optoelectronic ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 in the 135°-315° direction after being pre-treated at -4V and then applying an ultraviolet light pulse.

[0029] Figure 10 This is a current-time curve of the photoelectric ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 in the 135°-315° direction after being pre-treated with +4V and then applying an ultraviolet light pulse. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0031] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0032] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0034] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0035] Example 1 Preparation of a multi-angle inverted optoelectronic ferroelectric device with in-plane domains Figure 1 .

[0036] The schematic diagram of the structure of the optoelectronic ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 is shown in FIG. Figure 2 ; Among them, 1: insulating substrate; 2: inert metal electrode; 3: two-dimensional ferroelectric material layer.

[0037] Example 1

[0038] Preparation of optoelectronic ferroelectric devices with multi-angle in-plane domain flipping:

[0039] S1. The quartz substrate was ultrasonically cleaned in trichloroethylene, acetone, ethanol and secondary deionized water in an ultrasonic cleaning machine for 10 minutes each to remove dust, grease and other impurities on the surface of the substrate, and then blown dry;

[0040] S2. Evenly spin-coating a layer of photoresist on a clean quartz substrate, engraving a planar octagonal electrode pattern on the wafer by maskless photolithography, and removing the photoresist of the patterned portion by developing with a developer to reveal the pattern on the quartz substrate;

[0041] S3, depositing inert metal gold on the quartz substrate obtained in S2, the deposition method is thermal evaporation, the parameters of the thermal evaporation method are: the chamber background vacuum is greater than 10 -4 Pa; the purity of the Au wire of the evaporation material is 99.99%; the heating current is 105A; the thermal evaporation time is 10 minutes;

[0042] S4, soaking the wafer obtained in S3 in acetone solution, cleaning it with an ultrasonic cleaner for 1 minute to remove the photoresist on the substrate surface, taking away the gold except the photolithographic pattern, and drying it;

[0043] S5. Use mechanical peeling to peel off the α-In2Se3 thin film, use an optical microscope to find the two-dimensional α-In2Se3 thin film to be transferred, use PDMS to transfer the peeled two-dimensional α-In2Se3 thin film to the inert metal electrode through the transfer table, and make it cover the intersection of the planar octagonal structure electrode to obtain an in-plane domain multi-angle flipping optoelectronic ferroelectric device, where the thickness of the evaporated planar octagonal structure electrode is 24nm, and the thickness of the transferred two-dimensional α-In2Se3 thin film is 40nm.

[0044] The photoelectric ferroelectric device with multi-angle in-plane domain flipping prepared in Example 1 was tested:

[0045] The first part (away from the easy polarization axis):

[0046] A +5V electric pulse (pulse time 3s) was applied to the 0°-180° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2 The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 3 .

[0047] from Figure 3 It can be seen that the device has negative photoconductivity response in the directions of 0°-180°, 45°-225°, 90°-270°, and 135°-315°, and the negative photoconductivity response is strongest in the direction of 0°-180°.

[0048] A -5V electric pulse (pulse time 3s) was applied to the 0°-180° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2 The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 4 .

[0049] from Figure 4 It can be seen that the light response of the device in the direction of 0°-180° becomes positive photoconductivity, and the light response in the directions of 45°-225°, 90°-270°, and 135°-315° is still negative photoconductivity, but compared with Figure 3 (+5V pretreatment) The light response intensity became weaker.

[0050] The test order is determined by Figures 3 to 4 , which can make the polarization in the 0°-180° direction switch from ↓ to ↑, will affect the weakening of the light response in other directions.

[0051] A +5V electric pulse (pulse time 3s) was applied to the 45°-225° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2 The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 5 .

[0052] from Figure 5 It can be seen that the device shows a positive photoconductive response in the 0°-180° direction, and a negative photoconductive response in the 45°-225°, 90°-270°, and 135°-315° directions. The positive photoconductive response intensity in the 0°-180° direction is relatively low compared to Figure 4 The forward photoconductive response intensity in the 0°-180° direction becomes weaker.

[0053] Tested by Figures 4 to 5 , the polarization state of the device is Similar vector decomposition will result in the 0°-180° direction Figure 4 There was almost no change in other directions, 90°-270° and 135°-315°, with slight strengthening.

[0054] A -5V electric pulse (pulse time 3s) was applied to the 45°-225° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 6 .

[0055] from Figure 6 It can be seen that the device shows a positive photoconductive response in the directions of 0°-180° and 45°-225°, and a negative photoconductive response in the directions of 90°-270° and 135°-315°. The positive photoconductive response intensity in the direction of 0°-180° is relatively low compared with Figure 5 The forward photoconductive response intensity in the 0°-180° direction becomes stronger.

[0056] Tested by Figures 5 to 6 , the polarization state of the device is Similar vector decomposition will result in the 0°-180° direction Figure 5 The light response is enhanced.

[0057] The second part (close to the easy polarization axis):

[0058] A -5V electric pulse (pulse time 3s) was applied to the 90°-270° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2 The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 7 .

[0059] from Figure 7 It can be seen that the device shows a positive photoconductive response in the directions of 0°-180° and 90°-270°, and a negative photoconductive response in the directions of 45°-225° and 135°-315°. The positive photoconductive response intensity in the direction of 0°-180° is lower than that in Figure 6 The forward photoconductive response intensity in the 0°-180° direction is almost unchanged, and the photoresponse in the 45°-225° direction is Figure 6 The positive photoconductivity response shown in the experiment changes to a negative photoconductivity response, and the light response intensity becomes weaker.

[0060] The test order is determined by Figures 6 to 7 , the polarization state of the device is Since the 90°-270° direction is close to the 45°-225° direction, and atoms are more likely to displace in the 90°-270° direction, the polarization in the 45°-225° direction is very weak, almost absent, and the light response is weak; while the 0°-180° direction is perpendicular to the 90°-270° direction, and the displacement of atoms in the 90°-270° direction does not affect the 0°-180° direction, so in Figure 6On this basis, the light response in the 0°-180° direction remains almost unchanged; the light response in the 135°-315° direction does not change much.

[0061] A +5V electric pulse (pulse time 3s) was applied to the 90°-270° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2 The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 8 .

[0062] from Figure 8 It can be seen that the device exhibits a positive photoconductive response in the 0°-180° direction and a negative photoconductive response in the 45°-225°, 90°-270°, and 135°-315° directions. The light response intensity in the 0°-180°, 45°-225°, and 135°-315° directions is significantly lower than that in the Figure 7 The photoresponse intensity of (-5V pretreatment) remained almost unchanged.

[0063] Tested by Figures 7 to 8 , the polarization state of the device is Since the polarization in the 45°-225° direction is very weak, the polarization reversal in the 90°-270° direction does not have a significant effect on the light response in the 45°-225° direction. Figure 7 The basic principle is almost unchanged; the directions of 0°-180° and 135°-315° are also almost unchanged.

[0064] A -5V electric pulse (pulse time 3s) was applied to the 135°-315° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2 The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 9 .

[0065] from Figure 9 It can be seen that the device shows a positive photoconductive response in the directions of 0°-180° and 135°-315°, and a negative photoconductive response in the directions of 45°-225° and 90°-270°. The positive photoconductive response intensity in the direction of 0°-180° is lower than that in Figure 8 The positive photoconductive response intensity in the 0°-180° direction is weakened, and the negative photoconductive response intensity in the 90°-270° direction is weaker than that in the Figure 8 The negative photoconductive response intensity in the 90°-270° direction becomes weaker.

[0066] Tested by Figures 8 to 9 , the polarization state of the device is Due to competition, the polarization in the 0°-180° direction almost does not exist, and the light response is weak; in the 90°-270° direction, due to vector decomposition, the light response is Figure 8 The light response in the direction of 45°-225° is weak.

[0067] A +5V electric pulse (pulse time 3s) was applied to the 135°-315° direction of the in-plane domain multi-angle flip photoelectric ferroelectric device for pretreatment, and then a light with a wavelength of 405nm and an intensity of 5.98W / cm 2 The ultraviolet light acts as a pulse signal (pulse time 2s, pulse interval 1.4s). The current-time curve after applying three light pulses is shown in Figure 10 .

[0068] from Figure 10 It can be seen that the device exhibits a positive photoconductive response in the 0°-180° direction, and a negative photoconductive response in the 45°-225°, 90°-270°, and 135°-315° directions. The negative photoconductive response intensity in the 90°-270° direction is relatively Figure 8 The negative photoconductive response intensity in the 90°-270° direction becomes stronger.

[0069] Tested by Figures 9 to 10 , the polarization state of the device is The light response in the 90°-270° direction will be Figure 9 The light response in the directions of 0°-180° and 45°-225° is weak.

[0070] The present invention Figures 3 to 10 1-8, 2-7, 3-6, and 4-5 correspond to currents in directions of 0°-180°, 45°-225°, 90°-270°, and 135°-315°, respectively.

[0071] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An optoelectronic ferroelectric device with multi-angle inversion of in-plane domains, characterized in that: The structure includes an insulating substrate, an inert metal electrode with a planar octagonal structure and a two-dimensional ferroelectric layer combined in sequence, or an insulating substrate, a two-dimensional ferroelectric layer and an inert metal electrode with a planar octagonal structure combined in sequence; the intersection of the inert metal electrode with a planar octagonal structure is in contact with the two-dimensional ferroelectric layer; the material of the two-dimensional ferroelectric layer is two-dimensional α-In2Se3.

2. The optoelectronic ferroelectric device with multi-angle in-plane domain flipping according to claim 1, characterized in that: The thickness of the planar octagonal structured inert metal electrode is 15 to 25 nm.

3. The optoelectronic ferroelectric device with multi-angle in-plane domain flipping according to claim 1, characterized in that: The thickness of the two-dimensional α-In2Se3 is 35 to 45 nm.

4. A method for preparing the optoelectronic ferroelectric device with multi-angle in-plane domain flipping according to any one of claims 1 to 3, characterized in that: When the in-plane domain multi-angle flipping optoelectronic ferroelectric device structure comprises an insulating substrate, an inert metal electrode with a planar octagonal structure, and a two-dimensional ferroelectric layer that are sequentially combined, the preparation steps include: A planar octagonal inert metal electrode is generated on an insulating substrate using a mask method, and then a two-dimensional α-In2Se3 is transferred to the planar octagonal inert metal electrode, where the intersection of the planar octagonal inert metal electrode contacts the two-dimensional ferroelectric layer, thereby obtaining the optoelectronic ferroelectric device with multi-angle inversion of the in-plane domains; When the in-plane domain multi-angle flipping optoelectronic ferroelectric device structure comprises an insulating substrate, a two-dimensional ferroelectric layer, and an inert metal electrode with a planar octagonal structure that are sequentially combined, the preparation steps include: First, the two-dimensional α-In2Se3 is transferred to an insulating substrate, and a planar octagonal structured inert metal electrode is generated on one side of the insulating substrate where the two-dimensional α-In2Se3 is transferred using a mask method. The intersection of the planar octagonal structured inert metal electrode contacts the two-dimensional ferroelectric layer to obtain the optoelectronic ferroelectric device with multi-angle in-plane domain flipping.

5. The method for preparing an optoelectronic ferroelectric device with multi-angle in-plane domain flipping according to claim 4, characterized in that: The inert metal electrode is deposited by thermal evaporation or magnetron sputtering.

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