A method for preparing a transferable layered bismuth oxyselenide semiconductor film by hetero-layer interface regulation

Abstract

This invention belongs to the field of semiconductor materials technology and discloses a method for preparing transferable layered bismuth oxide selenide semiconductor thin films by heterolayer interface control. The method includes: 1) activating and growing a substrate; 2) depositing an interface-controlled heterolayer, which is a two-dimensional material or a water-soluble oxide; 3) CVD growing a Bi₂O₂Se thin film on the heterolayer; and 4) using a polymer support film to assist wet peeling, separating the film from the substrate and transferring it to a target substrate. This invention solves the problem of non-destructive transfer due to excessively strong adhesion between the film and substrate by introducing a heterolayer with weak interfacial interactions, and is applicable to fields such as flexible electronics and silicon-based integration.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, and specifically to a method for preparing transferable layered bismuth-oxygen selenide semiconductor thin films by heterolayer interface modulation. Background Technology

[0002] Layered bismuth oxide selenium (Bi₂O₂Se) is composed of [Bi₂O₂]. 2+ Cation layer and [Se] 2- A tetragonal two-dimensional semiconductor material with alternating anion layers stacked along the c-axis exhibits ultra-high room-temperature carrier mobility (up to 20,000 cm⁻¹). 2 / (V With its suitable infrared bandgap (approximately 0.8 eV), excellent air and thermal stability, it has irreplaceable application value in fields such as high-speed, low-power electronic devices, highly sensitive infrared photoelectric detection, and flexible wearable devices. Currently, the mainstream preparation method for layered Bi2O2Se thin films is chemical vapor deposition (CVD). However, this method generally adopts the mode of direct growth on the surface of native substrates (such as mica, sapphire, and single-crystal silicon), which has the following key technical bottlenecks: Strong interfacial bonding makes it impossible to transfer without damage: Strong chemical bonds or lattice coupling are easily formed between the native substrate and the Bi2O2Se thin film, resulting in excessively high interfacial bonding energy. The film adheres firmly to the substrate and is difficult to peel off completely, making it impossible to transfer to target functional substrates such as flexible substrates or silicon-based device wafers. The transfer process causes severe damage: forcibly peeling the film by mechanical scraping, strong acid corrosion and other methods can easily lead to structural damage such as cracks, wrinkles and grain boundary cracks. At the same time, it can also cause an increase in defects such as selenium vacancies and a significant decrease in carrier mobility. Interface residual contamination: Substrate debris, corrosion products or transfer medium impurities may remain during the stripping process, contaminating the thin film interface, leading to increased dark current and reduced on / off ratio of the device, which seriously affects the performance stability of the device. Poor integration compatibility: It cannot achieve efficient heterogeneous integration of Bi2O2Se with silicon-based CMOS processes and gate-around device structures, which limits its application in advanced logic devices and 3D integration. In existing technologies, simply improving the exfoliation process cannot fundamentally solve the core problem of strong interfacial interactions. While traditional interface-controlled heterolayer materials (such as ordinary SiO2) can reduce adhesion to some extent, they introduce new problems such as increased interfacial state density and decreased film crystallinity. In recent years, high-k oxides (such as β-Bi2SeO5) and two-dimensional van der Waals materials (such as h-BN) have provided new directions for interface control due to their characteristics such as no dangling bonds at the interface, excellent dielectric properties, and the ability to form weak van der Waals interactions. However, a systematic interface control scheme for heterolayers has not yet been formed, and it is impossible to simultaneously meet the dual requirements of high-quality film growth and non-destructive transferability. There is an urgent need to develop a preparation method that takes into account growth quality, transfer efficiency, and integration compatibility. Summary of the Invention

[0003] To address the problems of excessive bonding between bismuth oxy selenide (BOS) thin films and growth substrates in existing technologies, difficulty in non-destructive transfer, and performance degradation after transfer, a method for preparing transferable layered BOS semiconductor thin films based on interface-controlled heterolayer interface regulation is provided.

[0004] To address the aforementioned technical problems, this invention introduces an interface-controlled heterolayer of two-dimensional material or soluble oxide between the substrate and the bismuth oxide-selenium semiconductor thin film. The interface-controlled heterolayer of two-dimensional material constructs a pure van der Waals weak bond interface, eliminating strong chemical bond adhesion; the interface-controlled heterolayer of soluble oxide passivates dangling bonds on the substrate surface and reduces interfacial polarization and adhesion energy. This allows for precise adjustment of the interaction force between the substrate and the thin film interface, ultimately achieving easy peeling and precise transfer of the thin film to any target substrate under the premise of high-quality Bi2O2Se growth.

[0005] This invention provides a method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface control, comprising the following steps: (1) Select a growth substrate and perform surface activation treatment on it to obtain the activated substrate surface; (2) A layer of interface-controlled heterogeneous layer with a thickness of 0.3 to 5 nm is deposited or grown on the substrate surface after activation in step (1). The interface-controlled heterogeneous layer is a two-dimensional material or a water-soluble oxide, which constructs an intermediate transition interface that weakens the interfacial bonding force. The ultra-thin interface-controlled heterogeneous layer ensures the interface control effect without affecting the preferred growth and crystallization quality of Bi2O2Se layer. (3) Using bismuth source and selenium source as precursors, supplemented by oxygen and inert carrier gas atmosphere, layered Bi2O2Se semiconductor thin film is directionally grown on the surface of the interface-controlled heterolayer obtained in step (2) by chemical vapor deposition (CVD). (4) Utilizing the property of the interface-controlled heterolayer to weaken the interface interaction, a polymer support film is used to assist wet peeling to completely peel the layered Bi2O2Se semiconductor film obtained in step (3) from the growth substrate and transfer it to the surface of the target functional substrate. The polymer support film is then removed to obtain a transferable layered bismuth-oxygen selenide semiconductor film.

[0006] In the above method for preparing transferable layered bismuth-oxygen selenide semiconductor thin films by heterolayer interface regulation, preferably, in step (1), the growth substrate is any one of fluorophlogopite, sapphire, and SrTiO3 substrate.

[0007] Preferably, in step (1), before surface activation treatment, a cleaning process is performed, wherein the cleaning process is to ultrasonically clean in acetone, anhydrous ethanol and deionized water for ≥10 min each, and then blow dry with nitrogen. The surface activation treatment is ultraviolet ozone treatment, oxygen plasma treatment, or annealing treatment; the ultraviolet ozone treatment time is 5–15 min; the oxygen plasma treatment power is 50–150 W, and the treatment time is 3–10 min; the annealing treatment temperature is 800–1000℃. Surface activation treatment can ensure the cleanliness of the substrate surface and facilitate the uniform formation of heterogeneous films by controlling the interface. Preferably, in step (2), the two-dimensional material is a composite of one or more of hexagonal boron nitride, graphene, WSe2, and WS2; the interface-controlled heterolayer formed by the two-dimensional material forms a van der Waals weak bond interface with the Bi2O2Se film, thereby weakening the strong chemical bond coupling between the substrate and Bi2O2Se. Preferably, in step (2), the water-soluble oxide is an ultrathin Sr3Al2O6, SrTiO3, or SiO2 with a thickness of 1–5 nm. This is used to passivate the surface dangling bonds of the growth substrate, reduce interfacial electrostatic interactions and chemical bond coupling, and decrease the film peeling resistance.

[0008] Preferably, in step (3), the bismuth source is Bi2O3, the selenium source is Bi2Se3, the total carrier gas flow rate of inert carrier gas and oxygen is 50-200 sccm, and the volume fraction of oxygen is 1%-5%.

[0009] Preferably, in step (3), the growth temperature of the layered Bi2O2Se semiconductor thin film grown directionally by chemical vapor deposition is 420-600 °C, and the cavity pressure is 50-400 Pa; the thickness of the obtained layered Bi2O2Se semiconductor thin film is 5-10 nm.

[0010] Preferably, in step (4), the polymer-supported film-assisted wet peeling specifically uses water or an alkaline solution with a pH of 7.5–8.5 as the wetting solution, and wets it at 25–60 °C to dissolve the interface-controlled heterolayer or weaken the bonding force between the interface-controlled heterolayer and the substrate and / or the Bi2O2Se film. When the interface-controlled heterolayer is a water-soluble oxide, the wetting solution dissolves it after wetting; when the heterolayer is a two-dimensional material, the wetting solution weakens the van der Waals forces through interface intercalation (e.g., by utilizing the surface tension of water).

[0011] Preferably, in step (4), the polymer support film used is a polymethyl methacrylate film or a polydimethylsiloxane film, which is removed by heating or acetone; after peeling and transfer, the film is free of cracks and defects. Preferably, in step (4), the target functional substrate is any one of a silicon substrate, a silicon oxide substrate, a polyimide flexible substrate, a polyethylene terephthalate flexible substrate, a photoresist temporary substrate, or a silicon nitride dielectric substrate.

[0012] The method for preparing transferable layered bismuth oxy selenide semiconductor thin films using heterolayer interface modulation of the present invention produces an independent layered structure. At least one surface of this structure exhibits van der Waals surface features formed due to separation from the interface-modulated heterolayer interface, and this surface is free of residual chemical bonds from the growth substrate and the interface-modulated heterolayer. The interface-modulated heterolayer is a two-dimensional material or a water-soluble oxide. Flexible electronic devices, silicon-based heterojunction chips, or infrared photodetectors can be fabricated using this method for preparing transferable layered bismuth oxy selenide semiconductor thin films using heterolayer interface modulation.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention creatively introduces the concept of "interface-controlled heterogeneous layer", which fundamentally replaces the strong interaction (chemical bond, electrostatic coupling) between the substrate and Bi2O2Se with weak interaction (van der Waals force) or forms a removable sacrificial layer, realizing the reusability of the native substrate and the multiple lossless transfer of the thin film, and solving a key technical problem that has long existed in this field.

[0014] 2. For the first time in the same process, this invention not only ensures the high crystallinity, high mobility, low defects and high electrical properties of Bi2O2Se grown by chemical vapor deposition, but also completely breaks through the bottleneck of direct growth that cannot be transferred, giving the film a new characteristic of being transferable. The transfer process is gentle and reliable, and the film is intact and undamaged, successfully overcoming the contradiction that traditional methods cannot achieve.

[0015] 3. In this invention, the substrate after peeling is intact and can be directly reused; the thin film layer structure is complete, without cracks or wrinkles; the dissolution or peeling products of the interface-controlled heterolayer are non-toxic and harmless; the interface-controlled heterolayer is ultra-thin and easy to deposit; the peeling conditions are mild, without strong acid or strong alkali corrosion, and do not contaminate the thin film interface.

[0016] 4. The freestanding Bi2O2Se thin film prepared by this invention can be transferred to any target substrate, including but not limited to SiO2 / Si, flexible PI / PET, silicon nitride, etc., just like a film being applied. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 These are process flow diagrams of embodiments 1-3 of the present invention; Figure 2 This is a schematic diagram of the material cross-sectional structure before peeling and transfer in Embodiments 1-3 of the present invention; Figure 3 This is a schematic diagram of the cross-sectional structure of the material after peeling and transfer in Embodiments 1-3 of the present invention; Figure 4 These are comparative images of the Bi₂O₂Se thin films obtained in Example 1 and Comparative Example 1 of the present invention; wherein, Figure 4 a represents the Bi₂O₂Se thin film transferred after direct growth in Comparative Example 1. Figure 4 b is the Bi2O2Se thin film transferred after heterointercalation in Example 1. Detailed Implementation

[0019] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0020] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0021] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0022] Reference Figure 1The present invention provides the following embodiments based on the process flow diagram.

[0023] Example 1 This embodiment provides a method for preparing a transferable layered bismuth-oxygen-selenium semiconductor thin film by heterolayer interface control. A 10nm thick Bi₂O₂Se thin film is epitaxially grown on a Sr₃Al₂O₆ / SrTiO₃ composite substrate. The specific operation is as follows (e.g.) Figure 1 ): Step 1. Construction of composite substrate 1.1) A single-crystal strontium titanate (SrTiO3) (001) crystal plane oriented substrate was placed in an oxygen atmosphere and annealed at 1000℃ to prepare a titanium dioxide termination surface; 1.2) The substrate surface was observed using atomic force microscopy (AFM) to confirm the formation of clearly defined atomic-level steps and plateau structures; 1.3) Pulsed laser deposition (PLD) technology was used, with a 248nm krypton fluoride excimer laser as the deposition source; 1.4) Place the pretreated substrate into the deposition chamber and set the deposition temperature to 950℃ and the oxygen partial pressure to 1×10⁻⁶. -4 To deposit a water-soluble Sr3Al2O6 sacrificial film; 1.5) By monitoring the intensity oscillations of reflected high-energy electron diffraction (RHEED), deposition was stopped when four oscillation cycles were observed, confirming that the Sr3Al2O6 film thickness was one unit cell (approximately 1.5 nm). After film deposition, the oxygen partial pressure in the chamber was maintained >10. -4 The sample was allowed to cool naturally to room temperature, resulting in a SrTiO3 substrate with a Sr3Al2O6 interface-regulated heterolayer deposited on it, which is the Sr3Al2O6 / SrTiO3 composite substrate. Step 2. Chemical vapor deposition (CVD) growth of Bi2O2Se semiconductor thin films 2.1) Select Bi2O3 powder with a purity ≥99.99% and Bi2Se3 with a purity ≥99.99% as precursors, and place them in crucibles in different temperature zones of the CVD reactor (Bi2Se3 in the low temperature zone and Bi2O3 in the high temperature zone) to ensure that the precursors are free from deliquescence and impurity contamination; at the same time, prepare an oxygen source (oxygen with a purity ≥99.999%) and an inert carrier gas (Ar with a purity ≥99.999%), connect them to the reactor gas path system, and perform airtightness testing; 2.2) Fix the Sr3Al2O6 / SrTiO3 composite substrate prepared in step 1 on the sample holder of the CVD reactor, ensuring that the substrate surface is perpendicular to the diffusion direction of the precursor vapor and is within the constant temperature zone of the reactor to ensure the uniformity of film growth. 2.3) Close the reactor chamber and start the vacuum pump to evacuate the chamber until the vacuum level reaches 1×10⁻⁶.-3 Below Pa, remove residual air from the chamber; then introduce inert carrier gas (Ar) at a flow rate of 100 sccm and purge continuously for 30 minutes to further remove impurities from the chamber and establish a stable inert atmosphere. 2.4) Maintain a continuous flow of inert carrier gas, start the reactor heating program, and heat the entire chamber to the target growth temperature range (600℃) at a heating rate of 10℃ / min. The temperature of the low-temperature zone where Bi2Se3 is located is controlled at 480℃, and the temperature of the high-temperature zone where Bi2O3 is located is controlled at 600℃. During the heating process, adjust the O2 flow rate through the gas valve to make the volume fraction of O2 in the mixed gas 1%, and at the same time adjust the inert carrier gas flow rate to 200 sccm to control the chamber pressure to be stable at 200 Pa. 2.5) After the reactor temperature, chamber pressure, and gas atmosphere reach the set values ​​and stabilize for 30 minutes, the heating program is started. Bi2O3 vapor and Bi2Se3 vapor diffuse towards the sample holder under the influence of the inert carrier gas, growing a layered Bi2O2Se semiconductor thin film. During the growth process, the chamber pressure (fluctuation range ≤ ±10 Pa) and temperature (fluctuation range ≤ ±5 °C) are monitored in real time to keep all parameters stable. The growth time is set to 30 minutes according to the target film thickness (10 nm). 2.6) After the preset growth time is reached, stop heating and keep the inert carrier gas continuously flowing in (the flow rate is maintained at 200 sccm) to allow the reactor to cool down naturally to room temperature in an inert atmosphere, so as to avoid stress cracking or lattice distortion of the film due to rapid cooling. 2.7) After the reactor temperature drops to room temperature, stop the inert carrier gas supply, slowly release the chamber pressure to atmospheric pressure, open the chamber and remove the sample to obtain a Sr3Al2O6 / SrTiO3 composite substrate with a layered Bi2O2Se semiconductor thin film deposited on it. The material cross-sectional structure is shown in [Figure number missing]. Figure 2 .

[0024] Step 3. Peel off the Bi2O2Se film and transfer it to the target substrate. 3.1) Spin-coat a polymethyl methacrylate (PMMA) film onto the cooled sample surface to form a support layer; 3.2) Immerse the sample with the PMMA support layer in room temperature deionized water and let it stand until the Sr3Al2O6 sacrificial layer is completely dissolved; 3.3) The PMMA-supported Bi₂O₂Se two-dimensional thin film was removed and transferred to the surface of the target substrate (silicon substrate). The PMMA support layer was then removed with acetone, followed by cleaning with isopropanol to obtain the Bi₂O₂Se thin film coated on the target substrate surface. Its material cross-sectional structure is shown in [Figure number missing]. Figure 3 After the transfer, if Figure 4 Figure b in the diagram.

[0025] Example 2 This embodiment provides a method for preparing a transferable layered bismuth-oxygen-selenium semiconductor thin film by heterolayer interface control. A 5nm thick Bi₂O₂Se thin film is epitaxially grown on a WS₂ / SrTiO₃ composite substrate. The specific operation is as follows: Step 1. Construction of composite substrate 1.1) Select WS2 powder as the growth precursor, prepare inert carrier gas (Ar, purity ≥99.999%), connect it to the reactor gas path system and perform airtightness testing; 1.2) Perform standard cleaning on the SrTiO3 (STO) substrate (ultrasonic cleaning for ≥10 min each in acetone, anhydrous ethanol and deionized water, followed by drying with high-purity nitrogen). Fix the cleaned STO substrate on the sample holder of the CVD reactor, ensuring that the substrate surface is perpendicular to the direction of precursor vapor diffusion and is within the constant temperature zone of the reactor to ensure uniform film growth. 1.3) Close the reactor chamber, introduce inert carrier gas (Ar) at a flow rate of 100 sccm, and purge continuously for 30 minutes to further remove impurities inside the chamber and establish a stable inert atmosphere; 1.4) Maintain the carrier gas flow rate at 60 sccm, set the heating rate at 25℃ / min, start the reactor heating program, and heat to 1186℃; 1.5) After the reactor temperature reaches the set value and stabilizes for 30 minutes, the growth stage begins, lasting for 15 minutes. 1.6) After the preset growth time is reached, stop heating and keep the inert carrier gas flowing continuously to allow the reactor to cool down naturally in an inert atmosphere to avoid stress cracking or lattice distortion of the film due to rapid cooling. 1.7) After the reactor temperature drops to room temperature, stop the gas supply, open the chamber and take out the sample to obtain a SrTiO3 substrate with a WS2 interface-controlled heterolayer (about 0.6 nm) grown on it, thus obtaining a WS2 / SrTiO3 composite substrate.

[0026] Step 2. Chemical vapor deposition (CVD) growth of Bi2O2Se semiconductor thin films The growth of the Bi₂O₂Se semiconductor thin film was the same as in Specific Example 1, resulting in a WS₂ / SrTiO₃ composite substrate with a layered Bi₂O₂Se semiconductor thin film deposited on it. The material cross-sectional structure is shown in [Figure 1]. Figure 2 .

[0027] Step 3. Peel off the Bi2O2Se film and transfer it to the target substrate. 3.1) Spin-coat polydimethylsiloxane (PDMS) onto the cooled sample surface to form a support layer; 3.2) Immerse the sample with the PDMS support layer in room temperature deionized water and let it stand until Bi2O2Se and WSe2 separate; 3.3) The PDMS-supported Bi₂O₂Se two-dimensional thin film was removed and transferred to the surface of the target substrate (silicon substrate). The PDMS support layer was then removed by heating, yielding the Bi₂O₂Se thin film coated on the target substrate surface. Its material cross-sectional structure is shown in [Figure number missing]. Figure 3 .

[0028] Example 3 This embodiment provides a method for preparing a transferable layered bismuth-oxygen-selenium semiconductor thin film by heterolayer interface control. A 5nm thick Bi₂O₂Se thin film is epitaxially grown on a WSe₂ / SrTiO₃ composite substrate. The specific operation is as follows: Step 1. Construction of composite substrate 1.1) Select WSe2 powder as the growth precursor, prepare inert carrier gas (Ar, purity ≥99.999%), connect it to the reactor gas path system and perform airtightness testing; 1.2) Perform standard cleaning on the SrTiO3 (STO) substrate (ultrasonic cleaning for ≥10 min each in acetone, anhydrous ethanol and deionized water, followed by drying with high-purity nitrogen). Fix the cleaned STO substrate on the sample holder of the CVD reactor, ensuring that the substrate surface is perpendicular to the direction of precursor vapor diffusion and is within the constant temperature zone of the reactor to ensure uniform film growth. 1.3) Close the reactor chamber, introduce inert carrier gas (Ar) at a flow rate of 100 sccm, and purge continuously for 30 minutes to further remove impurities inside the chamber and establish a stable inert atmosphere; 1.4) Maintain a gas flow rate of 50 sccm, set the heating rate to 25℃ / min, start the reactor heating program, and heat to 1050℃; 1.5) After the reactor temperature reaches the set value and stabilizes for 30 minutes, the growth stage begins, lasting for 15 minutes. 1.6) After the preset growth time is reached, stop heating and keep the inert carrier gas flowing continuously to allow the reactor to cool down naturally in an inert atmosphere to avoid stress cracking or lattice distortion of the film due to rapid cooling. 1.7) After the reactor temperature drops to room temperature, stop the gas supply, open the chamber and take out the sample to obtain a SrTiO3 substrate with a WSe2 interface-controlled heterolayer (about 1.2 nm) grown on it, which is the WSe2 / SrTiO3 composite substrate.

[0029] Step 2. Chemical vapor deposition (CVD) growth of Bi2O2Se semiconductor thin films The growth of the Bi₂O₂Se semiconductor thin film was the same as in Specific Example 1, resulting in a WSe₂ / SrTiO₃ composite substrate with a layered Bi₂O₂Se semiconductor thin film deposited on it. The material cross-sectional structure is shown in [Figure 1]. Figure 2 .

[0030] Step 3. Peel off the Bi2O2Se film and transfer it to the target substrate. 3.1) Spin-coat polydimethylsiloxane (PDMS) onto the cooled sample surface to form a support layer; 3.2) Immerse the sample with the PDMS support layer in room temperature deionized water and let it stand until Bi2O2Se and WSe2 separate; 3.3) The PDMS-supported Bi₂O₂Se two-dimensional thin film was removed and transferred to the surface of the target substrate (silicon substrate). The PDMS support layer was then removed by heating, yielding the Bi₂O₂Se thin film coated on the target substrate surface. Its material cross-sectional structure is shown in [Figure number missing]. Figure 3 .

[0031] Comparative Example 1 This embodiment provides a method for preparing a transferable layered bismuth-oxygen-selenium semiconductor thin film by heterolayer interface modulation. A 10 nm thick Bi₂O₂Se film is epitaxially grown on a SrTiO₃ composite substrate. The specific operation is as follows: Step 1. SrTiO3 substrate pretreatment A titanium dioxide termination surface was prepared by annealing a single-crystal strontium titanate (SrTiO3) (001) crystal plane oriented substrate at 1000℃ in an oxygen atmosphere. Step 2. Growth of layered Bi₂O₂Se semiconductor thin films by chemical vapor deposition. 2.1) Select Bi2O3 powder with a purity ≥99.99% and Bi2Se3 with a purity ≥99.99% as precursors, and place them in crucibles in different temperature zones of the CVD reactor (Bi2Se3 in the low temperature zone and Bi2O3 in the high temperature zone) to ensure that the precursors are free from deliquescence and impurity contamination; at the same time, prepare oxygen (oxygen with a purity ≥99.999%) and inert carrier gas (Ar with a purity ≥99.999%), connect them to the reactor gas path system and perform airtightness testing; 2.2) Fix the SrTiO3 substrate prepared in step 1 on the sample holder of the CVD reactor, ensuring that the substrate surface is perpendicular to the direction of precursor vapor diffusion and is within the constant temperature zone of the reactor to ensure the uniformity of film growth. 2.3) Close the reactor chamber and start the vacuum pump to evacuate the chamber until the vacuum level reaches 1×10⁻⁶. -3 Below Pa, remove residual air from the chamber; then introduce inert carrier gas (Ar) at a flow rate of 100 sccm and purge continuously for 30 minutes to further remove impurities from the chamber and establish a stable inert atmosphere. 2.4) Maintain a continuous flow of inert carrier gas, start the reactor heating program, and heat the entire chamber to the target growth temperature range (600℃) at a heating rate of 10℃ / min. The temperature of the low-temperature zone where Bi2Se3 is located is controlled at 480℃, and the temperature of the high-temperature zone where Bi2O3 is located is controlled at 600℃. During the heating process, adjust the O2 flow rate through the gas valve to make the volume fraction of O2 in the mixed gas 1%, and at the same time adjust the inert carrier gas flow rate to 200 sccm to control the chamber pressure to be stable at 200 Pa. 2.5) After the reactor temperature, chamber pressure, and gas atmosphere reach the set values ​​and stabilize for 30 minutes, the heating program is started. Bi2O3 vapor and Bi2Se3 vapor diffuse towards the sample holder under the influence of the inert carrier gas, growing a layered Bi2O2Se semiconductor thin film. During the growth process, the chamber pressure (fluctuation range ≤ ±10 Pa) and temperature (fluctuation range ≤ ±5 °C) are monitored in real time to keep all parameters stable. The growth time is set to 30 minutes according to the target film thickness (10 nm). 2.6) After the preset growth time is reached, stop heating and keep the inert carrier gas continuously flowing in (the flow rate is maintained at 200 sccm) to allow the reactor to cool down naturally to room temperature in an inert atmosphere, so as to avoid stress cracking or lattice distortion of the film due to rapid cooling. 2.7) After the reactor temperature drops to room temperature, stop the inert carrier gas supply, slowly release the chamber pressure to atmospheric pressure, open the chamber and remove the sample to obtain an SrTiO3 substrate with a layered Bi2O2Se semiconductor thin film deposited on it. The material cross-sectional structure is shown in [Figure number missing]. Figure 2 .

[0032] Step 3. Transfer Bi₂O₂Se onto the silicon substrate. 3.1) Spin-coat a polymethyl methacrylate (PMMA) film onto the cooled sample surface to form a support layer; 3.2) The sample with the PMMA support layer was transferred to the surface of the target substrate (silicon substrate). The PMMA support layer was then removed with acetone, followed by cleaning with isopropanol to obtain a Bi₂O₂Se thin film coated on the target substrate surface. After transfer, as shown... Figure 4 Figure a in the diagram.

[0033] pass Figure 4 The comparison clearly shows that the Bi2O2Se sample transferred without the method of the present invention is small in size and irregular in shape; while the Bi2O2Se obtained by the method of the present invention is complete in size, regular in shape, and without obvious damage.

Claims

1. A method for preparing transferable layered bismuth-oxygen selenide semiconductor thin films by heterolayer interface modulation, characterized in that, Includes the following steps: (1) Select a growth substrate and perform surface activation treatment on it to obtain the activated substrate surface; (2) A layer of interface-controlled heterogeneous layer with a thickness of 0.3 to 5 nm is deposited or grown on the surface of the substrate after activation in step (1). The interface-controlled heterogeneous layer is a two-dimensional material or a water-soluble oxide. (3) Using bismuth source and selenium source as precursors, supplemented by oxygen and inert carrier gas atmosphere, layered Bi2O2Se semiconductor thin film is directionally grown on the surface of the interface-controlled heterolayer obtained in step (2) by chemical vapor deposition. (4) Using a polymer-supported film-assisted wet peeling method, the layered Bi2O2Se semiconductor film obtained in step (3) is completely peeled off from the growth substrate and transferred to the surface of the target functional substrate. The polymer-supported film is removed to obtain a transferable layered bismuth-oxygen selenide semiconductor film.

2. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface control according to claim 1, characterized in that, In step (1), the growth substrate is any one of fluorinated phlogopite, sapphire, and SrTiO3 substrate.

3. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface control according to claim 2, characterized in that, In step (1), before surface activation treatment, the surface is cleaned. The cleaning process is to ultrasonically clean the surface in acetone, anhydrous ethanol and deionized water for ≥10 min each, and then blow it dry with nitrogen. The surface activation treatment is ultraviolet ozone treatment, oxygen plasma treatment, or annealing treatment; the ultraviolet ozone treatment time is 5 to 15 min; the oxygen plasma treatment power is 50 to 150 W, and the treatment time is 3 to 10 min; the annealing treatment temperature is 800 to 1000℃.

4. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface modulation according to claim 1, characterized in that, In step (2), the two-dimensional material is a composite of one or more of hexagonal boron nitride, graphene, WSe2 and WS2; the interface-controlled heterolayer formed by the two-dimensional material forms a van der Waals weak bond interface with the Bi2O2Se thin film.

5. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface modulation according to claim 1, characterized in that, In step (2), the water-soluble oxide is an ultrathin Sr3Al2O6, SrTiO3 or SiO2 with a thickness of 1 to 5 nm.

6. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface modulation according to claim 1, characterized in that, In step (3), the bismuth source is Bi2O3, the selenium source is Bi2Se3, the total carrier gas flow rate of inert carrier gas and oxygen is 50-200 sccm, and the volume fraction of oxygen is 1%-5%.

7. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface modulation according to claim 1, characterized in that, In step (3), the growth temperature of the layered Bi2O2Se semiconductor thin film grown by chemical vapor deposition is 420-600 °C, and the cavity pressure is 50-400 Pa; the thickness of the obtained layered Bi2O2Se semiconductor thin film is 5-10 nm.

8. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface modulation according to claim 1, characterized in that, In step (4), the polymer support film-assisted wet peeling is specifically achieved by using water or an alkaline solution with a pH of 7.5 to 8.5 as the wetting solution and wetting at 25 to 60 °C, so as to dissolve or weaken the bonding force between the interface regulation heterolayer and the substrate and / or the Bi2O2Se film.

9. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface modulation according to claim 8, characterized in that, In step (4), the polymer support film used is a polymethyl methacrylate film or a polydimethylsiloxane film, which is removed by heating or by dissolving with acetone.

10. The method for preparing a transferable layered bismuth-oxygen selenide semiconductor thin film by heterolayer interface modulation according to claim 1, characterized in that, In step (4), the target functional substrate is any one of silicon substrate, silicon oxide substrate, polyimide flexible substrate, polyethylene terephthalate flexible substrate, photoresist temporary substrate or silicon nitride dielectric substrate.

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