Self-supporting single crystal oxide thin film, preparation method thereof and flexible electronic device

Abstract

The invention belongs to the technical field of thin film manufacturing, and particularly relates to a self-supporting single crystal oxide thin film, a preparation method thereof and a flexible electronic device. Comprising the following steps: preparing a sacrificial layer material according to a lattice constant of an oxide material, so that the lattice mismatch rate of the sacrificial layer material and the oxide material is not higher than 1.7%; the method comprises the following steps: obtaining a single crystal substrate, and preparing a sacrificial layer and a single crystal oxide layer which are sequentially laminated on the surface of the single crystal substrate from a sacrificial layer material and an oxide material; and etching to remove the sacrificial layer to obtain the self-supporting single crystal oxide film. The lattice parameter matching degree of the sacrificial layer and the single crystal oxide layer is high, so that lattice mismatch of the sacrificial layer and the single crystal oxide layer is reduced, lossless stripping of the single crystal oxide layer can be realized, the integrity of the self-supporting single crystal oxide film is ensured, and the excellent performance of the self-supporting single crystal oxide film is kept; the flexible self-supporting single crystal oxide film is obtained and is suitable for being applied to flexible electronic devices.

Description

Technical Field

[0001] This application belongs to the technical field of thin film manufacturing, and particularly relates to a self-supporting single crystal oxide thin film, a preparation method thereof, and a flexible electronic device. Background Art

[0002] With the increasing demand for intelligent, portable, and efficient electronic devices, flexible hybrid electronic technology has developed rapidly. In this field, piezoelectric materials that can convert mechanical energy and electrical energy into each other can be integrated into various flexible electronic devices to achieve efficient energy harvesting and sensing functions, and are the first choice for flexible electronic devices. Among many piezoelectric materials, self-supporting piezoelectric single crystal oxide thin films have both high piezoelectricity and high flexibility, and are a very promising class of materials. Usually, the self-supporting piezoelectric single crystal oxide thin film is grown on a single crystal substrate with a sacrificial layer material such as L 1-x Sr x MnO 3 ,Sr 3 Al 2 O 6 and then the single crystal oxide material is grown. After the growth is completed, the sacrificial layer is dissolved to obtain a self-supporting single crystal thin film. Since the material is epitaxially grown and the types of soluble sacrificial layer materials are limited, many types of materials cannot be made flexible by this method. For the materials that can be made flexible by this method, due to the large lattice constant difference between the sacrificial layer material and the piezoelectric single crystal material, serious lattice mismatch occurs, resulting in a large number of cracks and wrinkles in the single crystal thin film after peeling, making it difficult to further apply the thin film to device preparation.

[0003] Therefore, it is urgent to overcome the problems that the materials cannot be made flexible due to the insufficient types of sacrificial layers, and the self-supporting thin film obtained after peeling is damaged due to the lattice mismatch between the sacrificial layer material and the piezoelectric single crystal material. Summary of the Invention

[0004] The purpose of this application is to provide a self-supporting single crystal oxide thin film, a preparation method thereof, and a flexible electronic device, aiming to solve to a certain extent the problems that the materials cannot be made flexible due to the insufficient types of existing sacrificial layers, and the self-supporting thin film obtained after peeling is damaged due to the lattice mismatch between the sacrificial layer material and the piezoelectric single crystal material.

[0005] To achieve the above application purpose, the technical solution adopted in this application is as follows: In the first aspect, this application provides a preparation method of a self-supporting single crystal oxide thin film, including the following steps: Obtain an oxide material with a perovskite structure, and prepare a sacrificial layer material according to the lattice constant of the oxide material, so that the lattice mismatch rate between the sacrificial layer material and the oxide material is not higher than 1.7%; Obtain a single-crystal substrate, and form a sacrificial layer and a single-crystal oxide layer which are sequentially stacked on the surface of the single-crystal substrate from the sacrificial layer material and the oxide material; Etch away the sacrificial layer to obtain a self-supporting single-crystal oxide thin film.

[0006] In some embodiments, the oxide material includes PbZr 0.52 Ti 0.48 O 3 , 0.68Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -0.32PbTiO 3 , BaTiO 3 , BiFeO 3 , SrRuO 3 , BiMnO 3 , PbTiO 3 at least one of.

[0007] In some embodiments, the sacrificial layer material includes Ba x Sr (3-x) Al 2 O 6 , L 1-y Sr y MnO 3 , SrRuO 3 , SrVO 3 , YBa 2 Cu 3 O 7 , SrCoO 2.5 at least one of; wherein, 0≤x<3, 0<y<1.

[0008] In some embodiments, the lattice constant of the sacrificial layer material can be continuously adjusted between 3.961 Å and 4.124 Å.

[0009] In some embodiments, the sacrificial layer material includes Ba x Sr (3-x) Al 2 O 6 , 0≤x<3.

[0010] In some embodiments, the preparation steps of the Ba x Sr (3-x) Al 2 O 6 sacrificial layer material include: according to the Ba x Sr (3-x) Al 2 O 6The stoichiometric ratio of the metal elements, mix BaO, SrO and Al 2 O 3 powders and sinter them under the condition of a temperature of 800 °C to 1000 °C to obtain the Ba x Sr (3-x) Al 2 O 6 sacrificial layer material.

[0011] In some embodiments, the oxide material includes PbZr 0.52 Ti 0.48 O 3 or 0.68Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -0.32PbTiO 3 .

[0012] In some embodiments, the sacrificial layer is prepared by pulsed laser deposition technology, and the growth conditions include: a temperature of 700 °C to 750 °C, a flowing oxygen pressure of 18 mTorr to 50 mTorr, a laser energy density of 0.8 J / cm 2 ~1.2 J / cm 2 , and a pulsed laser frequency of 2 Hz to 5 Hz.

[0013] In some embodiments, the single-crystalline oxide layer is prepared by pulsed laser deposition technology, and the growth conditions include: a temperature of 600 °C to 700 °C, a flowing oxygen pressure of 50 mTorr to 100 mTorr, a laser energy density of 0.8 J / cm 2 ~1.2 J / cm 2 , and a pulsed laser frequency of 5 Hz to 10 Hz.

[0014] In some embodiments, the single-crystalline substrate includes at least one of SrTiO 3 , LaAlO 3 , GdScO 3 .

[0015] In some embodiments, the step of etching to remove the sacrificial layer includes: after setting a support layer on the surface of the single-crystalline oxide layer, soaking it in an etching solution to remove the sacrificial layer by wet etching, and obtaining the self-supporting single-crystalline oxide thin film on the surface of the support layer.

[0016] In some embodiments, the material of the support layer includes at least one of polydimethylsiloxane, polymethyl methacrylate, polyethylene terephthalate, and polyvinyl alcohol.

[0017] In some embodiments, the etching solution comprises an ethanol solution with a mass fraction of 10% - 20%.

[0018] In some embodiments, the thickness of the support layer is 100 μm - 200 μm.

[0019] In some embodiments, the thickness of the sacrificial layer is 50 nm - 150 nm.

[0020] In some embodiments, the thickness of the single-crystalline oxide layer is 150 nm - 250 nm.

[0021] In a second aspect, the present application provides a self-supporting single-crystalline oxide thin film, which is prepared by the above method.

[0022] In some embodiments, the surface integrity of the self-supporting single-crystalline oxide thin film is not less than 95%.

[0023] In a third aspect, the present application provides a flexible electronic device, which includes the above self-supporting single-crystalline oxide thin film.

[0024] In some embodiments, in the flexible electronic device, a metal bottom electrode and a metal top electrode are disposed on both sides of the self-supporting single-crystalline oxide thin film.

[0025] In some embodiments, the thickness of the metal bottom electrode is 50 nm - 150 nm.

[0026] In some embodiments, the thickness of the metal top electrode is 50 nm - 150 nm.

[0027] In some embodiments, the metal materials in the metal bottom electrode and the metal top electrode independently include at least one of Pt, Au, Ag, and Cu.

[0028] The preparation method of the self-supporting single-crystalline oxide film provided in the first aspect of the present application formulates a sacrificial layer material according to the lattice constant of the oxide material, so that the lattice mismatch rate between the sacrificial layer material and the oxide material is not higher than 1.7%. Then, a sacrificial layer and a single-crystalline oxide layer arranged in a stacked manner are sequentially formed on the surface of the single-crystalline substrate. Due to the high lattice parameter matching degree between the sacrificial layer and the single-crystalline oxide layer, the lattice mismatch between the sacrificial layer and the single-crystalline oxide layer is reduced. After the sacrificial layer is etched away, the number of the single-crystalline oxide layer is little affected, the non-destructive peeling of the single-crystalline oxide layer can be realized, the integrity of the self-supporting single-crystalline oxide film can be ensured, and the excellent performance of the self-supporting single-crystalline oxide film can be maintained, and a flexible self-supporting single-crystalline oxide film is obtained, which is suitable for application in flexible electronic devices. It solves the problem that due to the large difference in lattice constants between the sacrificial layer material and the single-crystalline oxide material, serious lattice mismatch causes a large number of cracks and wrinkles in the single-crystalline oxide layer after peeling, resulting in the inability of the single-crystalline oxide layer to be peeled off without damage and the inability to be flexible, affecting the application of the single-crystalline oxide layer film in flexible electronic devices.

[0029] The self-supporting single-crystalline oxide film provided in the second aspect of the present application is prepared by the above method. Due to the high lattice parameter matching degree between the sacrificial layer and the single-crystalline oxide layer, the lattice mismatch between the sacrificial layer and the single-crystalline oxide layer is reduced, and the non-destructive peeling of the single-crystalline oxide layer is realized. Therefore, the integrity of the self-supporting single-crystalline oxide film is high, the surface of the film is basically intact, and the excellent performance of the self-supporting single-crystalline oxide film is maintained, which is suitable for application in flexible electronic devices.

[0030] The surface integrity of the self-supporting single-crystalline oxide film adopted in the third aspect of the present application is high, the surface of the film is basically intact, and it has good flexibility and can be widely applied to flexible electronic devices. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1 It is a schematic flowchart of the preparation method of the self-supporting single-crystalline oxide film provided in the embodiment of the present application; Figure 2 It is a schematic flowchart of the preparation method of the self-supporting single-crystalline oxide film provided in Embodiment 1 of the present application; Figure 3 It is a schematic flowchart of the flexible electronic device provided in Embodiment 2 of the present application; Figure 4It is a schematic structural diagram of the flexible electronic device provided in Embodiment 2 of the present application; Figure 5 It is a test diagram of the BSAO / PZT structure provided in Embodiment 1 of the present application and the SAO / PZT structure provided in Comparative Example 1, in which deionized water is used to simultaneously wet-etch the sacrificial layers in the two structures; Figure 6 It is an optical microscope observation diagram of the PZT thin film peeled off from the BSAO / PZT structure in Embodiment 1 of the present application and the PZT thin film peeled off from the SAO / PZT structure in Comparative Example 1; Figure 7 It is an X-ray diffraction test diagram of the BSAO / PZT structure provided in Embodiment 1 of the present application and the SAO / PZT structure provided in Comparative Example 1 before and after etching the sacrificial layer; Figure 8 It is a leakage current test diagram of the flexible electronic device with a self-supporting PZT thin film in Embodiment 2 of the present application and the rigid electronic device with a rigid PZT thin film in Comparative Example 2; Figure 9 It is a ferroelectricity test diagram of the flexible electronic device with a self-supporting PZT thin film in Embodiment 2 of the present application and the rigid electronic device with a rigid PZT thin film in Comparative Example 2; Figure 10 It is an X-ray diffraction test diagram of the SAO / PMNPT structure provided in Embodiment 3 of the present application before and after etching the sacrificial layer; Figure 11 It is a polarization test diagram of the SRO / PMNPT / Pt rigid electronic device and the PDMS / Pt / PMNPT / Pt flexible electronic device in Embodiment 4 of the present application respectively. Detailed implementation manners

[0033] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] In the present application, the term "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0035] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0036] It should be understood that in various embodiments of this application, the magnitudes of the serial numbers of the above - mentioned processes do not imply the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0037] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms "a" and "the" used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0038] The weight of the relevant components mentioned in the embodiments of the specification of this application not only can refer to the specific content of each component, but also can represent the proportional relationship of the weights between the components. Therefore, as long as the content of the relevant components in the embodiments of the specification of this application is scaled up or down proportionally, it is within the scope disclosed in the embodiments of the specification of this application. Specifically, the mass described in the embodiments of the specification of this application can be mass units well - known in the chemical industry such as μg, mg, g, kg, etc.

[0039] The terms "first" and "second" are only used for descriptive purposes to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of this application, the first XX can also be called the second XX, and similarly, the second XX can also be called the first XX. Thus, the features defined with "first" and "second" can explicitly or implicitly include one or more of such features.

[0040] In the first aspect of the embodiments of this application, a method for preparing a self - supported single - crystal oxide film is provided. As shown in the Figure 1 accompanying drawings, it includes the following steps: S10. Obtain an oxide material with a perovskite structure, prepare a sacrificial layer material according to the lattice constant of the oxide material, so that the lattice mismatch rate between the sacrificial layer material and the oxide material is not higher than 1.7%; S20. Obtain a single-crystal substrate, and form a sacrificial layer and a single-crystal oxide layer which are sequentially stacked on the surface of the single-crystal substrate with a sacrificial layer material and an oxide material. S30. Etch and remove the sacrificial layer to obtain a self-supporting single-crystal oxide thin film.

[0041] It should be noted that in the embodiments of the present application, the lattice mismatch rate refers to the dislocations and distortions generated between two crystals due to the mismatch of lattice parameters. The formula for calculating the lattice mismatch rate is: lattice mismatch rate = |a1 - a2| / a1× 100%, where a1 and a2 represent the lattice constants of the oxide material and the sacrificial layer material respectively. In the embodiments of the present application, the lattice mismatch rate between the sacrificial layer material and the oxide material is not higher than 1.7%, which means that the lattice constant of the sacrificial layer material is not higher than or not lower than 1.7% of the lattice constant of the oxide material. Exemplarily, when the lattice constant of the oxide material is 4 Å, the lattice constant of the sacrificial layer material is not higher than 1.7% of the lattice constant of the oxide material, that is, not higher than 4.068 Å; at the same time, the lattice constant of the sacrificial layer material is not lower than 1.7% of the lattice constant of the oxide material, that is, not lower than 3.932 Å.

[0042] The preparation method of the self-supporting single-crystal oxide thin film provided in the first aspect of the embodiments of the present application prepares a sacrificial layer material according to the lattice constant of the oxide material, so that the lattice mismatch rate between the sacrificial layer material and the oxide material is not higher than 1.7%. Then, a sacrificial layer and a single-crystal oxide layer which are stacked in sequence are formed on the surface of the single-crystal substrate. Since the lattice parameter matching degree between the sacrificial layer and the single-crystal oxide layer is high, the lattice mismatch between the sacrificial layer and the single-crystal oxide layer is reduced. After etching and removing the sacrificial layer, the number of the single-crystal oxide layer is little affected, the non-destructive peeling of the single-crystal oxide layer can be realized, the integrity of the self-supporting single-crystal oxide thin film can be ensured, and the excellent performance of the self-supporting single-crystal oxide thin film can be maintained, and a flexible self-supporting single-crystal oxide thin film is obtained, which is suitable for application in flexible electronic devices. It solves the problem that due to the large difference in lattice constants between the sacrificial layer material and the single-crystal oxide material, serious lattice mismatch causes a large number of cracks and wrinkles in the single-crystal oxide layer after peeling, resulting in the inability of the single-crystal oxide layer to be peeled off without damage and the inability to be flexible, affecting the application of the single-crystal oxide layer thin film in flexible electronic devices.

[0043] In the above step S10: In some possible implementation manners, the lattice mismatch rate between the sacrificial layer material and the oxide material is not higher than 1.7%, 1.65%, 1.61%, 1.6%, 1.55%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1% or 0%, etc., which are typical but non-limiting arbitrary point values or interval values between any two point values.

[0044] In some possible implementations, the oxide material includes PbZr 0.52 Ti 0.48 O 3 , 0.68Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -0.32PbTiO 3 (PMNPT), BaTiO 3 , BiFeO 3 , SrRuO 3 , BiMnO 3 , PbTiO 3 and at least one of them. The oxide materials in the embodiments of the present application include a variety of functional oxide materials with perovskite structures, and these oxide materials are all suitable for preparing self-supporting single-crystal oxide films. Moreover, the lattice constants of the single-crystal oxides prepared from these oxide materials have been fully reflected in previous studies, and the lattice constants are all known, which is conducive to regulating the sacrificial layer material with lattice constant matching through the oxide materials.

[0045] In some possible implementations, the oxide material includes PbZr 0.52 Ti 0.48 O 3 (PZT). PZT has excellent ferroelectric properties, enabling PZT to exhibit unique polarization behavior under the action of an electric field, thereby realizing the storage and release of charges. This property makes PZT have important applications in electronic devices such as ferroelectric field-effect transistor memories (FFETs). PZT also has excellent piezoelectric properties, making PZT widely used in fields such as sensors, actuators, and piezoelectric ceramics. PZT also has pyroelectric properties, making PZT have important applications in thermal sensors such as infrared detectors. PZT has a high dielectric constant, making PZT have important applications in electronic devices such as capacitors. In addition, PZT also has good chemical stability and mechanical strength, which enables PZT to maintain stable performance under harsh environments and withstand large mechanical stresses.

[0046] In some possible implementations, the oxide material includes 0.68Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -0.32PbTiO 3 (PMNPT), which belongs to the perovskite structure (ABO 3 type), usually presents a tetragonal or rhombohedral structure at room temperature, and is a typical relaxor ferroelectric-ferroelectric solid solution material. PMNPT has an extremely high piezoelectric coefficient (d33 can reach above 2000 pC / N), which is much higher than traditional piezoelectric materials and is suitable for high-performance sensors, transducers, and actuators. The dielectric constant ( ) can reach above 5000 at room temperature and exhibits significant dielectric relaxation behavior near the phase transition temperature. In addition, it also has a large electrostrictive strain ( can reach above 1%), which is suitable for precision displacement control devices.

[0047] In some possible implementation manners, the sacrificial layer material includes at least one of Ba x Sr (3-x) Al 2 O 6 、L 1-y Sr y MnO 3 、SrRuO 3 、SrVO 3 、YBa 2 Cu 3 O 7 、SrCoO 2.5 , where 0 ≤ x < 3 and 0 < y < 1. These sacrificial layers have different lattice constants, and a mixed sacrificial layer material matching the lattice constant of the single-crystal oxide material can be formulated by combining different sacrificial layer materials. In addition, these sacrificial layer materials all have good solubility and can be removed by wet etching. Among them, Ba x Sr (3-x) Al 2 O 6 is soluble in water and has a fast dissolution rate. L 1-y Sr y MnO 3 is soluble in an acidic solution of KI and HCl and will exhibit completely different phase structures under different premises of y. SrRuO 3 is soluble in a NaIO 4 solution. SrVO 3 is soluble in water at about 50 °C. YBa 2 Cu 3 O 7 is soluble in an HCl solution. SrCoO 2.5 is soluble in an acetic acid organic acid solution with a concentration of about 36%.

[0048] In some possible implementation manners, the lattice constant of the sacrificial layer material can be continuously adjusted within the range of 3.961 Å to 4.124 Å. Specifically, it can be any typical but non-limiting point value such as 3.961 Å, 3.98 Å, 4.0 Å, 4.05 Å, 4.1 Å, 4.124 Å, or an interval value between any two point values. The lattice constant of the sacrificial layer material in the embodiments of the present application can be continuously adjusted by controlling the components of different sacrificial layer materials to form a compound sacrificial layer material, reducing the limitation of the types of materials that can be made flexible by the epitaxial growth - wet etching method. By reducing the lattice mismatch between the sacrificial layer and the single-crystalline oxide material, the lossless peeling of the single-crystalline oxide can be achieved. Moreover, by controlling the sacrificial layer material, the growth crystal phase of the sacrificial layer can be accurately controlled, and a super-tetragonal phase sacrificial layer thin film that can be rapidly dissolved can be prepared, improving the preparation efficiency of the self-supporting single-crystalline oxide thin film.

[0049] In some possible implementation manners, the sacrificial layer material includes Ba x Sr (3-x) Al 2 O 6 (BSAO), where 0 ≤ x < 3. In this case, for Ba x Sr (3-x) Al 2 O 6 , different values of x can all be dissolved in water. Since the atomic radius of Ba is larger than that of Sr, the lattice constant of Ba 3 Al 2 O 6 is also larger than that of Sr 3 Al 2 O 6 . By adjusting the contents of Ba and Sr, the lattice constant of BSAO can be continuously adjusted from 3.907 Å to 4.124 Å. Specifically, when adjusting the lattice constant in the sacrificial layer, precise control of the parameters can be achieved by adjusting the ratio of Sr 3 Al 2 O 6 (SAO) and Ba 3 Al 2 O 6 (BAO). Among them, the larger X is, the larger the proportion of Ba is, and the larger the lattice constant of BSAO is. It can be continuously adjusted from Sr 3 Al 2 O 6 (SAO) with a lattice constant of 3.961 Å to Ba 3 Al 2 O 6(BAO). In the actual application process, the value of x depends on the lattice constant of the target self-supporting single-crystalline oxide film. x can be flexibly adjusted from 0 to 3. By adjusting the components of the two water-soluble materials SAO and BAO, Ba with the target lattice constant is obtained. x Sr (3-x) Al 2 O 6 The sacrificial layer solves the problem that the piezoelectric single-crystalline material cannot be made flexible or cannot be peeled off without damage due to lattice constant mismatch, and maintains the excellent performance of the self-supporting single-crystalline oxide film. In the embodiments of the present application, the lattice constant of the sacrificial layer material can be continuously adjusted through the component regulation of BAO and SAO, reducing the limitation of the types of materials that can be made flexible by the epitaxial growth-wet etching method. By reducing the lattice mismatch between the sacrificial layer and the single-crystalline oxide material, the non-destructive peeling of the single-crystalline oxide is achieved. By precisely controlling the growth crystal phase of the sacrificial layer, a super-tetragonal phase BSAO film that can be quickly dissolved is prepared, increasing the preparation efficiency of the self-supporting single-crystalline oxide film.

[0050] In some possible implementation manners, Ba x Sr (3-x) Al 2 O 6 The preparation steps of the sacrificial layer material include: mixing BaO, SrO and Al x Sr (3-x) Al 2 O 6 powders according to the stoichiometric ratio of the metal elements in Ba 2 O 3 and sintering under the condition of a temperature of 800 °C to 1000 °C to obtain Ba x Sr (3-x) Al 2 O 6 sacrificial layer material. In this case, by adjusting the ratio of BaO and SrO in the raw material components, the value of x in the Ba x Sr (3-x) Al 2 O 6 sacrificial layer material can be adjusted, so as to obtain a sacrificial layer material with a lattice constant matching that of the oxide material. Among them, the sintering temperature ensures the crystallinity of the Ba x Sr (3-x) Al 2 O 6 ceramic target, so that when using this target to prepare and deposit the sacrificial layer film, it can have a good stoichiometric ratio and better crystallinity, ensuring the performance of the sacrificial layer material.

[0051] In the above step S20: In some possible implementation manners, the single-crystal substrate includes SrTiO3 (STO), LaAlO 3 , GdScO 3 At least one of them. The lattice constants of the substrate and the oxide layer often do not match, so the material grown on it is subject to in-plane compressive or tensile strain, and it is prone to breakage after peeling. Preferably, these single-crystal substrates can reduce the breakage caused by material peeling.

[0052] In some embodiments, the single-crystal substrate uses a single-crystal SrTiO 3 (STO) substrate with a (001) crystal orientation; that is, the crystal plane perpendicular to the c-axis in SrTiO 3 (STO) crystal is used as the substrate.

[0053] In some possible implementation manners, pulsed laser deposition technology is used to prepare the sacrificial layer, and the growth conditions include: the temperature is 700 °C to 750 °C, the flowing oxygen pressure is 18 mTorr to 50 mTorr, and the laser energy density is 0.8 J / cm 2 ~1.2 J / cm 2 , and the pulsed laser frequency is 2 Hz to 5 Hz. In this case, the preparation of the sacrificial layer is fully ensured. In some embodiments, the epitaxial growth conditions of the pulsed laser deposition technology for the sacrificial layer will affect the growth of the crystal phase of the BSAO sacrificial layer. The SAO material will exhibit a supertetragonal phase under this growth condition. The lattice constant of this phase is slightly different from that of the cubic phase SAO, so the prepared BSAO also has this supertetragonal phase. The dissolution rate of the BSAO in this phase is higher than that of the cubic phase SAO and BSAO.

[0054] Exemplarily, the temperature conditions for preparing the sacrificial layer by pulsed laser deposition technology can be typical but non-limiting arbitrary point values such as 700 °C, 720 °C, 740 °C, 750 °C, or interval values between any two point values. The flowing oxygen pressure can be typical but non-limiting arbitrary point values such as 18 mTorr, 20 mTorr, 25 mTorr, 30 mTorr, 35 mTorr, 40 mTorr, 45 mTorr, 50 mTorr, or interval values between any two point values. The laser energy density can be 0.8 J / cm 2 , 0.9 J / cm 2 , 1.0 J / cm 2 , 1.1 J / cm 2 , 1.2 J / cm 2 and other typical but non-limiting arbitrary point values or interval values between any two point values. The pulsed laser frequency can be typical but non-limiting arbitrary point values such as 2 Hz, 3 Hz, 4 Hz, 5 Hz, or interval values between any two point values.

[0055] In some possible implementation manners, the thickness of the sacrificial layer is 50 nm to 150 nm, and specifically, it can be typical but non-limiting arbitrary point values such as 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, or interval values between any two point values. This thickness not only ensures the quality of the subsequently prepared single-crystalline oxide layer, but also facilitates the subsequent removal of the sacrificial layer by etching, realizes the non-destructive peeling of the single-crystalline oxide layer, and guarantees the integrity of the self-supporting single-crystalline oxide thin film.

[0056] In some possible implementation manners, the pulsed laser deposition technique is used to prepare the single-crystalline oxide layer, and the growth conditions include: the temperature is 600 °C to 700 °C, the flowing oxygen pressure is 50 mTorr to 100 mTorr, and the laser energy density is 0.8 J / cm 2 ~1.2 J / cm 2 , and the pulsed laser frequency is 5 Hz to 10 Hz. In this case, the oxide material has good crystallinity. The oxide with good crystallinity has a certain growth window (i.e., the growth condition range). When growing within the growth window, slight changes in conditions have little impact on the film quality. Growing the film within the growth window is beneficial to obtaining a high-quality single-crystalline oxide layer.

[0057] Exemplarily, the temperature conditions for preparing the single-crystalline oxide layer by the pulsed laser deposition technique can be typical but non-limiting arbitrary point values such as 600 °C, 630 °C, 650 °C, 700 °C, or interval values between any two point values. The flowing oxygen pressure can be typical but non-limiting arbitrary point values such as 50 mTorr, 60 Torr, 70 Torr, 80 Torr, 90 Torr, 100 mTorr, or interval values between any two point values. The laser energy density can be 0.8 J / cm 2 、0.9 J / cm 2 、1.0 J / cm 2 、1.1 J / cm 2 、1.2 J / cm 2 and other typical but non-limiting arbitrary point values or interval values between any two point values. The pulsed laser frequency can be typical but non-limiting arbitrary point values such as 5 Hz, 6 Hz, 7 Hz, 8 Hz, 9 Hz, 10 Hz, or interval values between any two point values.

[0058] In some possible implementation manners, the thickness of the single-crystalline oxide layer is 150 nm to 250 nm, and specifically, it can be typical but non-limiting arbitrary point values such as 150 nm, 180 nm, 200 nm, 230 nm, 250 nm, or interval values between any two point values. Within this thickness range, the single-crystalline oxide layer has high flexibility and is suitable for application in flexible electronic devices, with high application prospects.

[0059] In the above step S30: In some possible implementation manners, the step of etching and removing the sacrificial layer includes: after a support layer is disposed on the surface of the single-crystalline oxide layer, soaking it in an etching solution to remove the sacrificial layer by wet etching, and obtaining a self-supporting single-crystalline oxide thin film on the surface of the support layer. In this case, by using wet etching to dissolve and remove the sacrificial layer, the single-crystalline oxide layer is transferred to the surface of the support layer, and a self-supporting single-crystalline oxide thin film is obtained on the surface of the support layer. With the support of the support layer, it is more conducive to etching and removing the sacrificial layer to obtain a complete and undamaged self-supporting single-crystalline oxide thin film. In a further embodiment, the support layer is removed to obtain an independently self-supporting single-crystalline oxide thin film.

[0060] In some possible implementation manners, the material of the support layer includes at least one of polydimethylsiloxane, polymethyl methacrylate, polyethylene terephthalate, and polyvinyl alcohol. The material of the support layer in the embodiments of the present application uses these organic materials, which have high flexibility and are conducive to improving the integrity of the film layer.

[0061] In some possible implementation manners, polydimethylsiloxane (PDMS) with a ratio of prepolymer to cross-linking agent of (10~15):1 is used. After being fully stirred, it is spin-coated in a petri dish by a spin-coating method. The oxygen pressure is set to 0.1 Pa to 0.5 Pa in a bench-top vacuum drying oven, the curing temperature is set to 70°C to 100°C, and it is cured for 12 to 24 hours to obtain the support layer. Among them, the prepolymer and the cross-linking agent refer to the raw material components for preparing PDMS. The lower the ratio of the cross-linking agent, the stronger the viscosity of PDMS. The ratio of (10~15):1 can enable PDMS to effectively adhere to the thin film without affecting the transfer of the thin film when it is transferred to other substrates for the second time due to excessive viscosity.

[0062] In some possible implementation manners, the support layer is prepared in a clean and flat container, and the prepared support layer is cut into small pieces for use from the container. The PDMS support layer has thermal releasability. Not only can the thin film be stably present on the support layer after adhering to a single-crystalline oxide layer such as PZT, but also the single-crystalline oxide layer such as PZT and the PDMS support layer can be peeled off by heating when it is necessary to transfer to other substrates.

[0063] In some possible implementation manners, the thickness of the support layer is 100 μm to 200 μm, specifically, it can be typical but non-limiting arbitrary point values such as 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, or interval values between any two point values. The support layer with this thickness can fully ensure the support effect on the single-crystalline oxide layer and is also conducive to peeling off the support layer from the single-crystalline oxide layer during subsequent applications.

[0064] In some possible implementation manners, the sacrificial layer material is selected from Ba x Sr(3-x) Al 2 O 6 where \(0\leq x\lt3\); at this time, the etching solution includes an ethanol solution with a mass fraction of 10% - 20%. In this case, Ba x Sr (3-x) Al 2 O 6 The sacrificial layer is a water-soluble sacrificial layer, which can be etched and removed by dissolving in water, being green and environmentally friendly. The addition of ethanol is used to reduce the surface tension of water. An ethanol solution with a mass fraction of 10% - 20% can reduce the additional stress of the etchant on the single-crystal oxide layer. Excessive addition or too high concentration of ethanol may affect the dissolution rate. Exemplarily, the mass fraction of the ethanol solution can be any typical but non-limiting point value such as 10%, 12%, 15%, 18%, 20%, etc. or an interval value between any two point values.

[0065] In a second aspect, an embodiment of the present application provides a self-supporting single-crystal oxide thin film, which is prepared by the above method.

[0066] The self-supporting single-crystal oxide thin film provided by the embodiment of the present application is prepared by the above method. Since the lattice parameter matching degree between the sacrificial layer and the single-crystal oxide layer is high, the lattice mismatch between the sacrificial layer and the single-crystal oxide layer is reduced, realizing the non-destructive peeling of the single-crystal oxide layer. Therefore, the integrity of the self-supporting single-crystal oxide thin film is high, the surface of the thin film is basically intact, and the excellent properties of the self-supporting single-crystal oxide thin film are maintained, being suitable for application in flexible electronic devices.

[0067] In some possible implementation manners, the surface integrity of the self-supporting single-crystal oxide thin film is not less than 95%, specifically it can be 95%, 96%, 97%, 98%, 99%, 100%, etc. The surface integrity of the self-supporting single-crystal oxide thin film provided by the embodiment of the present application is high, and the surface of the thin film is basically intact.

[0068] In a third aspect, an embodiment of the present application provides a flexible electronic device, which includes the above self-supporting single-crystal oxide thin film.

[0069] The self-supporting single-crystal oxide thin film provided by the embodiment of the present application has high surface integrity, the surface of the thin film is basically intact, and it has good flexibility, and can be widely applied to flexible electronic devices.

[0070] In some possible implementation manners, the self-supporting single-crystal oxide thin film prepared by the embodiment of the present application has various electrical properties such as ferroelectricity, ferromagnetism, piezoelectricity, etc., and can be widely developed for applications in flexible electronic devices, including flexible power generation, flexible storage, flexible sensing, flexible energy storage and other devices.

[0071] In some possible implementation manners, in a flexible electronic device, a metal bottom electrode and a metal top electrode are disposed on two sides of a self-supporting single-crystal oxide thin film.

[0072] In some possible implementation manners, the thickness of the metal bottom electrode is 50 nm to 150 nm, and specifically may be 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, etc.

[0073] In some possible implementation manners, the thickness of the metal top electrode is 50 nm to 150 nm, and specifically may be 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, etc.

[0074] In some possible implementation manners, the metal materials in the metal bottom electrode and the metal top electrode independently include at least one of Pt, Au, Ag, and Cu.

[0075] To enable those skilled in the art to clearly understand the above implementation details and operations of this application, and to significantly reflect the advanced performance of the embodiments of this application, the following uses multiple embodiments to illustrate the above technical solutions.

[0076] Embodiment 1 A self-supporting single-crystal oxide thin film, as shown in the appendix Figure 2 shown, its preparation includes the steps: 1. Prepare a target material of Ba x Sr (3-x) Al 2 O 6 (BSAO), specifically, the firing conditions are to use BaO, SrO, and Al 2 O 3 powders with a molar ratio of 1.5:1.5:1 and sinter them into a ceramic target material at 850 °C to obtain Ba 1.5 Sr 1.5 Al 2 O 6 BSAO sacrificial layer material with a lattice constant of 4.047 Å.

[0077] 2. Use pulsed laser deposition technology on a single-crystal SrTiO 3 (STO) substrate with a (001) crystal orientation. First, grow a supertetragonal BSAO sacrificial layer. The specific growth conditions are: sputter-deposit a BSAO thin film with a thickness of 50 nm at 750 °C, a flowing oxygen pressure of 18 mTorr, a laser energy density of 1.2 J / cm 2 , and a laser frequency of 3 Hz, that is, the BSAO sacrificial layer. Subsequently, grow PbZr 0.52 Ti 0.48 O 3(PZT) thin film with a lattice constant of 4.05 Å, grown under the following conditions: 600 °C, flowing oxygen pressure of 100 mTorr, laser energy density of 1 J / cm 2 , a piezoelectric single crystal film with a thickness of 200 nm, namely a PZT single crystal oxide layer, was sputtered and deposited under a laser frequency of 10 Hz to obtain a BSAO / PZT structure, in which the absolute difference in lattice constants between the BSAO layer and the PZT layer was 0.003 Å, and the lattice constant of the BSAO layer was 0.074% higher than that of the PZT layer, namely, the lattice mismatch rate was 0.074%.

[0078] 3. Use polydimethylsiloxane (PDMS) with a prepolymer and cross-linking agent ratio of 10:1, stir it thoroughly, and then use the spin coating method to spin coat it in a culture dish. Set the oxygen pressure to 0.1Pa in a desktop vacuum drying oven, set the curing temperature to 80°C, and cure it for 24 hours as a support layer. Stick the support layer on the PZT surface, use deionized water to etch the BSAO sacrificial layer, add 10% anhydrous ethanol to the deionized water to reduce the surface tension of the deionized water, and obtain a self-supporting single crystal oxide film on the surface of the support layer, that is, a PZT / PDMS structure.

[0079] Example 2 A flexible electronic device, the process diagram is as shown in the attached Figure 3 As shown, its preparation comprises the steps of: After the BSAO / PZT structure is obtained in step 2 of Example 1, a 100nm thick Pt film is prepared on the PZT surface using magnetron sputtering technology under 4mTorr argon gas with a sputtering power of 40W for 400s. Then, a PDMS film is attached to the surface of the Pt film and wet-etched to remove the sacrificial layer, thereby obtaining a self-supporting PDMS / Pt / PZT structure, in which Pt is used as the bottom electrode. Subsequently, a mask with circular holes and magnetron sputtering technology are used to prepare a top electrode on the PZT surface to obtain a PDMS / Pt / PZT / Pt flexible electronic device. The side and surface structure schematics are shown in the attached figure. Figure 4 shown.

[0080] Example 3 A self-supporting single crystal oxide film, which is different from the first embodiment in that the sacrificial layer material is Sr 3 Al 2 O 6 (SAO), the lattice constant is 3.961Å, and the oxide layer material uses 0.68Pb(Mg) with a lattice constant of 4.026Å 1 / 3 Nb 2 / 3 ) 3 -0.32PbTiO 3Compare with (PMNPT). At this time, the absolute difference between the lattice constants of the sacrificial layer material and the oxide material is 0.065 Å. The lattice constant of the SAO layer is 1.61% higher than that of the PMNPT layer, that is, the lattice mismatch rate is 1.61%, and the SAO / PMNPT structure is prepared.

[0081] Its preparation includes the steps: 1. Prepare a target of Sr 3 Al 2 O 6 (SAO), and the specific firing conditions are to use SrO and Al with a molar ratio of 1.5:1 2 O 3 powders are fully mixed and sintered into a ceramic target at 850 °C to obtain Sr 3 Al 2 O 6 sacrificial layer material of SAO with a lattice constant of 3.961 Å.

[0082] 2. Use pulsed laser deposition technology on a single crystal Sr 3 Al 2 O 6 (SAO) substrate with (001) crystal orientation. First, grow a cubic phase SAO sacrificial layer. The specific growth conditions are: sputter-deposit a SAO thin film with a thickness of 50 nm at 750 °C, a flowing oxygen pressure of 18 mTorr, a laser energy density of 1.5 J / cm 2 and a laser frequency of 3 Hz, that is, the SAO sacrificial layer. Subsequently, grow 0.68Pb(Mg 1 / 3 Nb 2 / 3 )O 3 - 0.32PbTiO 3 (PMNPT) thin film with a lattice constant of 4.026 Å. The specific growth conditions are: sputter-deposit a piezoelectric single crystal thin film with a thickness of 200 nm at 600 °C, a flowing oxygen pressure of 100 mTorr, a laser energy density of 1 J / cm 2 and a laser frequency of 10 Hz, that is, the PMNPT single crystal oxide layer, to obtain the SAO / PMNPT structure.

[0083] Example 4 A rigid electronic device, its preparation includes the steps: using pulsed laser deposition technology and a single crystal STO substrate with (001) crystal orientation, setting the growth conditions as 700 °C, a flowing oxygen pressure of 150 mTorr, a laser energy density of 1 J / cm2, and a laser frequency of 5 Hz, sputter-deposit a SrRuO with a thickness of 50 nm 3The thin film is used as the bottom electrode, and then the PZT thin film is prepared under the above conditions. After taking it out, photoresist is spin-coated, and a circular pattern is prepared by exposure using a lithography machine. The circular Pt pattern is prepared by magnetron sputtering technology as the top electrode, and the STO / SRO / PMNPT / Pt rigid electronic device is obtained.

[0084] After the SAO / PMNPT structure is obtained in Step 2 of Example 3, on the surface of PMNPT, using magnetron sputtering technology, under 4 mTorr of argon, the sputtering power is 40 W, and a 100-nm-thick Pt thin film is prepared for 400 s. Subsequently, after attaching a PDMS thin film on the surface of the Pt thin film, wet etching is carried out. After etching away the sacrificial layer, the self-supporting PDMS / Pt / PMNPT structure is obtained, where Pt is used as the bottom electrode. Then, using a mask plate with round holes and magnetron sputtering technology, the top electrode is prepared on the surface of PMNPT again, and the PDMS / Pt / PMNPT / Pt flexible electronic device is obtained.

[0085] Comparative Example 1 A self-supporting single-crystalline oxide thin film, which is different from Example 1 in that: the sacrificial layer uses Sr 3 Al 2 O 6 (SAO) sacrificial layer for comparison. At this time, the absolute difference between the lattice constant of the sacrificial layer material and the lattice constant of the oxide material is 0.145 Å. The lattice constant of the SAO layer is 3.60% higher than the lattice constant of the PZT layer, that is, the lattice mismatch rate is 3.60%, and the SAO / PZT structure is obtained.

[0086] Its preparation includes the steps: 1. Prepare a target material with the composition of Sr 3 Al 2 O 6 (SAO), and the specific firing conditions are to fully mix SrO and Al 2 O 3 powders with a molar ratio of 1.5:1, sinter them into a ceramic target at 850 °C, and obtain the Sr 3 Al 2 O 6 SAO sacrificial layer material with a lattice constant of 3.905 Å.

[0087] 2. Using pulsed laser deposition technology, on the single-crystalline Sr 3 Al 2 O 6 (SAO) substrate with (001) crystal orientation, first, grow the supertetragonal phase SAO sacrificial layer, and the specific growth conditions are: at 750 °C, the flowing oxygen pressure is 18 mTorr, and the laser energy density is 1.2 J / cm 2, sputter-deposit an SAO thin film with a thickness of 50 nm under the condition that the laser frequency is 3 Hz, namely the SAO sacrificial layer. Subsequently, grow a PbZr 0.52 Ti 0.48 O 3 (PZT) thin film with a lattice constant of 4.05 Å. The specific growth conditions are as follows: at 600 °C, a flowing oxygen pressure of 100 mTorr, a laser energy density of 1 J / cm 2 , sputter-deposit a piezoelectric single-crystal thin film with a thickness of 200 nm under the condition that the laser frequency is 10 Hz, namely the PZT single-crystal oxide layer, to obtain an SAO / PZT structure.

[0088] Comparative Example 2 A rigid electronic device, the preparation of which includes the steps: using pulsed laser deposition technology and a single-crystal STO substrate with a (001) crystal orientation, setting the growth conditions as 700 °C, a flowing oxygen pressure of 150 mTorr, a laser energy density of 1 J / cm2, and a laser frequency of 5 Hz, sputter-deposit an SrRuO thin film with a thickness of 50 nm 3 as the bottom electrode, then prepare a PZT thin film under the above conditions, spin-coat a photoresist after taking it out, use a lithography machine to expose and prepare a circular pattern, and use magnetron sputtering technology to prepare a circular Pt pattern as the top electrode to obtain an STO / SRO / PZT / Pt rigid electronic device, the structure of STO / SRO / PZT / Pt. This sample is a non-peelable rigid electronic device sample with good performance, which is used for performance comparison with the PDMS / Pt / PZT / Pt flexible electronic device sample after peeling in Example 2.

[0089] In order to verify the progressiveness of the embodiments of the present application, the following performance tests were carried out: It should be noted that in the following embodiments of the present application, the self-supporting single-crystal oxide thin film is directly tested on the support layer. In other tests or subsequent experiments, the PDMS layer can be removed by heating according to needs, or the self-supporting single-crystal oxide thin film can be transferred to other substrates for use.

[0090] 1. Attach a PDMS support layer to the surface of the PZT in the BSAO / PZT structure prepared in Example 1 and the SAO / PZT structure prepared in Comparative Example 1, and simultaneously perform wet etching on the sacrificial layers in the two structures using deionized water. The test figures are attached Figure 5 as shown. It can be seen that the peeling speed of the PZT thin film with BSAO prepared in Example 1 of the present application is significantly faster than that of the PZT thin film with SAO prepared in Comparative Example 1. After 60 minutes of etching, the PZT thin film with the BSAO sacrificial layer is completely peeled off, while the PZT thin film with the SAO sacrificial layer takes 3 hours to complete etching and peeling.

[0091] Furthermore, the peeled-off film adheres completely to the PDMS surface, and the integrity of the film is observed using an optical microscope. As shown in the attached Figure 6 figure, it can be seen from the optical microscope that due to lattice mismatch, the PZT film obtained by peeling through the SAO sacrificial layer in Comparative Example 1 has a large number of wrinkles and damages after peeling, while the surface of the PZT film obtained by peeling through the BSAO sacrificial layer in Example 1 of the present application is intact.

[0092] 2. Use an X-ray diffractometer to test the crystal quality of the film. For the PZT film with SAO in Comparative Example 1 and the PZT film with BSAO in Example 1 of the present application, X-ray diffraction is respectively tested before and after etching the sacrificial layer, and the 2θ peak of the film is tested. As shown in the attached Figure 7 figure, it can be found that the peak position of the PZT film with the SAO sacrificial layer in Comparative Example 1 moves significantly after etching the sacrificial layer, indicating that the lattice constant of PZT has changed due to the removal of the SAO constraint, while the peak position of the PZT with the BSAO sacrificial layer in Example 1 does not change after etching, indicating that BSAO has no effect on PZT due to lattice constant matching.

[0093] 3. Use a probe station and TF3000 to test the electrical properties of the film. The leakage currents of the rigid electronic device of the rigid PZT film in Comparative Example 2 and the flexible electronic device of the self-supporting PZT film in Example 5 are respectively tested. The test results are as shown in the attached Figure 8 figure. It can be seen that the flexible electronic device of the flexible PZT film peeled in Example 5 and the rigid electronic device of the rigid film in Comparative Example 2 also maintain low leakage characteristics. The ferroelectricity of the two films is characterized, and the test results are as shown in the attached Figure 9 figure. It can be seen that the peeled-off PZT film still maintains good ferroelectricity.

[0094] 4. Use an X-ray diffractometer to test the crystal quality of the film. For the PMNPT film with SAO in Example 3, X-ray diffraction is respectively tested before and after etching the sacrificial layer, and the 2θ peak of the film is tested. As shown in the attached Figure 10 figure, the test results show that due to the small lattice mismatch between PMNPT and SAO, the position of the 2θ peak of PMNPT hardly changes before and after peeling, and the film still maintains good single-phase property.

[0095] 5. Polarization tests are respectively carried out on the SRO / PMNPT / Pt rigid electronic device and the PDMS / Pt / PMNPT / Pt flexible electronic device prepared in Example 4. The test results are as shown in the attached Figure 11 figure. The PMNPT films before and after peeling both maintain good ferroelectricity, and even the peeled-off film obtains a higher saturation polarization.

[0096] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A method for preparing a self-supporting single crystal oxide thin film, characterized in that: The following steps are involved: Obtaining an oxide material with a perovskite structure, and preparing a sacrificial layer material according to the lattice constant of the oxide material, so that the lattice mismatch rate between the sacrificial layer material and the oxide material is not higher than 1.7%; Obtaining a single crystal substrate, and forming a sacrificial layer and a single crystal oxide layer stacked in sequence by using the sacrificial layer material and the oxide material on the surface of the single crystal substrate; The sacrificial layer is removed by etching to obtain a self-supporting single crystal oxide film.

2. The method for preparing a self-supporting single crystal oxide thin film according to claim 1, characterized in that: The oxide material includes PbZr 0.52 Ti 0.48 O3, 0.68Pb(Mg 1 / 3 Nb 2 / 3 )O3-0.32PbTiO3, BaTiO3, BiFeO3, SrRuO3, BiMnO3, PbTiO3, at least one of.

3. The method for preparing a self-supporting single crystal oxide thin film according to claim 2, characterized in that: The sacrificial layer material includes Ba x Sr (3-x) Al2O6、L 1-y Sr y MnO3, SrRuO3, SrVO3, YBa2Cu3O7, SrCoO 2.5 At least one of, wherein 0≤x≤3, 0<y<1; And / or, the lattice constant of the sacrificial layer material can be continuously adjusted between 3.961Å and 4.124Å.

4. The method for preparing a self-supporting single crystal oxide thin film according to claim 3, characterized in that: The sacrificial layer material includes Ba x Sr (3-x) Al2O6, 0≤x<3; And / or, the Ba x Sr (3-x) The preparation steps of Al2O6 sacrificial layer material include: x Sr (3-x) The stoichiometric ratio of the metal elements in Al2O6 is obtained by mixing BaO, SrO and Al2O3 powders and sintering them at a temperature of 800°C to 1000°C to obtain the Ba x Sr (3-x) Al2O6 sacrificial layer material; And / or, the oxide material includes PbZr 0.52 Ti 0.48 O3 or 0.68Pb(Mg 1 / 3 Nb 2 / 3 )O3-0.32PbTiO3.

5. The method for preparing a self-supporting single crystal oxide thin film according to any one of claims 1 to 4, characterized in that: The sacrificial layer is prepared by pulsed laser deposition technology, and the growth conditions include: temperature of 700℃~750℃, flowing oxygen pressure of 18mTorr~50mTorr, laser energy density of 0.8 J / cm 2 ~1.2 J / cm 2 , the pulse laser frequency is 2 HZ~5HZ; And / or, the single crystal oxide layer is prepared by pulsed laser deposition technology, and the growth conditions include: temperature of 600°C to 700°C, flowing oxygen pressure of 50mTorr to 100mTorr, laser energy density of 0.8 J / cm 2 ~1.2 J / cm 2 , the pulse laser frequency is 5HZ~10HZ; And / or, the single crystal substrate includes at least one of SrTiO3, LaAlO3, and GdScO3; And / or, the step of etching away the sacrificial layer includes: after setting a supporting layer on the surface of the single crystal oxide layer, immersing it in an etching solution to remove the sacrificial layer by wet etching, and obtaining the self-supporting single crystal oxide film on the surface of the supporting layer.

6. The method for preparing a self-supporting single crystal oxide thin film according to claim 5, characterized in that: The material of the support layer includes at least one of polydimethylsiloxane, polymethyl methacrylate, polyethylene terephthalate, and polyvinyl alcohol; And / or, the etching solution comprises an ethanol solution with a mass fraction of 10% to 20%; And / or, the thickness of the support layer is 100 μm to 200 μm; And / or, the thickness of the sacrificial layer is 50nm~150nm; And / or, the thickness of the single crystal oxide layer is 150nm~250nm.

7. A self-supporting single crystal oxide thin film, characterized in that: The self-supporting single crystal oxide thin film is prepared by the method according to any one of claims 1 to 6.

8. The self-supporting single crystal oxide thin film according to claim 7, characterized in that: The surface integrity of the self-supporting single crystal oxide film is not less than 95%.

9. A flexible electronic device, characterized in that: The flexible electronic device comprises the self-supporting single crystal oxide thin film as described in any one of claims 7 to 8.

10. The flexible electronic device according to claim 9, characterized in that: In the flexible electronic device, a metal bottom electrode and a metal top electrode are provided on both sides of the self-supporting single crystal oxide film; And / or, the thickness of the metal bottom electrode is 50nm~150nm; And / or, the thickness of the metal top electrode is 50nm~150nm; And / or, the metal materials in the metal bottom electrode and the metal top electrode independently include at least one of Pt, Au, Ag, and Cu.

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