Bi3O2.5Se2 semiconductor material as well as preparation method and application thereof
By performing pre-annealing and annealing treatments on fluorinated mica substrates, the problem of insufficient size of Bi3O2.5Se2 material was solved, and large-size Bi3O2.5Se2 semiconductor material suitable for electronic and optoelectronic devices was prepared.
Patent Information
- Application Number
- CN202511094247.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-06
- Publication Date
- 2025-11-11
AI Technical Summary
The size of existing Bi3O2.5Se2 materials is generally less than 100 μm, which limits their application in large-scale electronic and optoelectronic devices.
Fluorocrystalline mica substrate was used as the growth substrate for Bi3O2.5Se2 semiconductor material. Pre-annealing and annealing were carried out in a mixed gas environment of inert gas and oxygen. Temperature, time and heating rate were controlled to promote the uniform diffusion and nucleation of precursor molecules on the substrate surface, forming Bi3O2.5Se2 semiconductor material with a lateral size greater than 100μm.
Bi3O2.5Se2 semiconductor material with a lateral dimension greater than 100μm was successfully prepared, which is suitable for electronic devices and optoelectronic devices, and enhances the potential for large-scale application of the material.
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Figure CN120933153A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to Bi3O 2.5 In the field of Se2 semiconductor materials technology, particularly relating to a Bi3O 2.5 Se2 semiconductor materials, their preparation methods, and applications. Background Technology
[0002] Two-dimensional semiconductors have become a hot topic in the research of novel electronic and optoelectronic materials over the past 20 years due to their tunable band gaps, atomically thin layers, and easily adjustable electronic properties. Among them, the bismuth oxyselenide family is particularly noteworthy for its high electron mobility, high stability, and suitable band gaps (e.g., Bi3O4). 2.5 Se2 (with a band gap of approximately 1.16 eV) has attracted significant attention in next-generation electronics and fundamental research. However, current Bi3O... 2.5 The size of synthesized Se2 materials is generally less than 100 μm, which severely limits their application in large-scale electronic and optoelectronic devices. Summary of the Invention
[0003] In view of this, the object of the present invention is to provide a Bi3O 2.5 Se2 semiconductor materials, their preparation methods, and applications; the preparation method can prepare Bi3O with a lateral dimension greater than 100 micrometers. 2.5 Se2 semiconductor material.
[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0005] This invention provides a Bi3O 2.5 The preparation method of Se2 semiconductor material includes the following steps:
[0006] A fluorinated mica substrate is placed on top of bismuth selenide, with the fractured surface of the fluorinated mica substrate facing the bismuth selenide. Then, under conditions of a mixture of inert gas and oxygen, pre-annealing and annealing are performed sequentially to obtain the Bi3O. 2.5 Se2 semiconductor materials;
[0007] The Bi3O 2.5 The lateral dimension of Se2 semiconductor material is >100μm.
[0008] Preferably, the fluorinated mica substrate is located 0.2 to 0.6 cm above the bismuth selenide.
[0009] Preferably, before performing the pre-annealing treatment, the atmosphere for the pre-annealing treatment is further washed with a mixture of inert gas and oxygen.
[0010] The inert gas and oxygen mixture is introduced at a rate ≥200 sccm and for a duration >5 min.
[0011] Preferably, the inert gas and oxygen mixture is introduced at a rate of 20 to 100 sccm.
[0012] Preferably, the pre-annealing treatment temperature is 350–480°C, and the holding time is 5–15 min.
[0013] Preferably, the heating rate to the pre-annealing temperature is 10–30 °C / min.
[0014] Preferably, the annealing temperature is 500–700°C, and the holding time is 10–30 min.
[0015] Preferably, the heating rate to the annealing temperature is 30–50 °C / min.
[0016] This invention also provides Bi3O prepared by the preparation method described above. 2.5 Se2 semiconductor material, Bi3O 2.5 The lateral dimension of Se2 semiconductor material is >100μm;
[0017] The Bi3O 2.5 The crystal lattice structure of Se2 semiconductor material belongs to the monoclinic crystal system;
[0018] The Bi3O 2.5 The lattice parameters of Se2 semiconductor material are: β = 102.91°.
[0019] The present invention also provides the Bi3O described in the above technical solution. 2.5 Applications of Se2 semiconductor materials in the fields of electronic devices and optoelectronic devices.
[0020] This invention provides a Bi3O 2.5 A method for preparing Se2 semiconductor material includes the following steps: placing a fluorinated mica substrate above bismuth selenide, with the fractured surface of the fluorinated mica substrate facing the bismuth selenide; then, under the condition of a mixed gas of inert gas and oxygen, performing pre-annealing and annealing treatments sequentially to obtain the Bi3O4 semiconductor material. 2.5 Se2 semiconductor material; Bi3O 2.5 The lateral dimension of the Se2 semiconductor material is >100 μm. The preparation method described in this invention uses a fluorine-containing mica substrate as the substrate for the Bi3O4 semiconductor. 2.5The substrate for Se2 semiconductor material deposition has the following advantages: high temperature resistance, remaining stable even at 1100℃, meeting the temperature requirements for material growth; and the surface of the fluorine mica substrate has a hexagonal symmetrical structure, which is consistent with the Bi3O4 substrate. 2.5 The symmetry of the layered direction of Se2 semiconductor materials is uniform, which is conducive to the epitaxy of the material; the fluorinated mica substrate is easy to peel off; compared with other substrates, the fluorinated mica substrate has very few dangling bonds on its surface, which is more conducive to the growth of large-size materials; furthermore, since the surface defects of fluorinated mica are mainly manifested as dangling bonds and atomic steps, these defects will inhibit the diffusion of precursor molecules. The inhibition of precursor molecule diffusion will restrict the lateral growth of the material, thus limiting the lateral size of the crystal. However, the pre-annealing treatment of this invention can effectively eliminate the dangling bonds on the surface of the fluorinated mica substrate, reduce the number of unpaired chemical bonds on the surface, and repair atomic steps, making the substrate surface smoother. This helps the precursor molecules to diffuse and nucleate uniformly on the substrate surface, promoting the lateral growth of the crystal material. Compared with the single-step heating growth method, the preparation method of this invention can effectively promote the lateral diffusion of precursor molecules on the mica surface and improve the growth of Bi3O 2.5 The lateral dimensions of the Se2 semiconductor material (single crystal material), the preparation method being Bi3O 2.5 The lateral epitaxial growth of Se2 semiconductor materials provides a more favorable environment. Attached Figure Description
[0021] Figure 1 This is a schematic diagram showing the positional relationship of bismuth selenide, fluorinated mica substrate, and ceramic boat in a single-temperature zone tube furnace during the preparation process described in Examples 1-3.
[0022] Figure 2 Bi3O prepared in Examples 1-3 2.5 SEM image of Se2 semiconductor material (scale bar: 200 μm);
[0023] Figure 3 Bi3O as described in Example 1 2.5 HRTEM images of Se2 semiconductor material in the planar and cross-sectional directions;
[0024] Figure 4 Bi3O as described in Example 1 2.5 TEM image and cross-sectional elemental distribution diagram of Se2 semiconductor material;
[0025] Figure 5 Bi3O as described in Comparative Example 1 2.5 SEM image of Se2 semiconductor material;
[0026] Figure 6 Bi3O as described in Comparative Example 2 2.5SEM image of Se2 semiconductor material;
[0027] Figure 7 Bi3O as described in Comparative Example 3 2.5 SEM image of Se2 semiconductor material. Detailed Implementation
[0028] This invention provides a Bi3O 2.5 The preparation method of Se2 semiconductor material includes the following steps:
[0029] A fluorinated mica substrate is placed on top of bismuth selenide, with the fractured surface of the fluorinated mica substrate facing the bismuth selenide. Then, under conditions of a mixture of inert gas and oxygen, pre-annealing and annealing are performed sequentially to obtain the Bi3O. 2.5 Se2 semiconductor materials;
[0030] The Bi3O 2.5 The lateral dimension of Se2 semiconductor material is >100μm.
[0031] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.
[0032] In this invention, the fluorinated mica substrate is preferably a freshly pyrolyzed fluorinated mica substrate. By selecting a freshly pyrolyzed fluorinated mica substrate, the pyrolysis surface is unaffected by dust, moisture, and particulate matter in the air, ensuring a clean substrate surface free from environmental contamination. This prevents substrate contamination and thus avoids affecting Bi3O. 2.5 Growth of Se2 semiconductor material crystal structure.
[0033] In this invention, the particle size of the bismuth selenide is preferably 15–45 μm. In an embodiment of this invention, the particle size of the bismuth selenide can be 30 μm. This invention does not impose any special limitations on the source of the bismuth selenide; any source well known to those skilled in the art can be used. In an embodiment of this invention, the bismuth selenide was purchased from Alfa and has a purity of 99.99%. In this invention, the bismuth selenide is preferably placed in a ceramic boat.
[0034] In this invention, the fluorinated mica substrate is preferably positioned 0.2 to 0.6 cm above the bismuth selenide. In an embodiment of this invention, the fluorinated mica substrate may be positioned 0.4 cm above the bismuth selenide.
[0035] In this invention, the bismuth selenide and fluorine mica substrate are preferably located at the central heat source.
[0036] Before performing the pre-annealing treatment, the present invention preferably includes purging the atmosphere of the pre-annealing treatment with a mixture of argon and oxygen to remove impurities from the tube. In the present invention, the introduction rate of the inert gas and oxygen mixture is preferably ≥200 sccm, and the time is preferably >5 min. In an embodiment of the present invention, the introduction rate of the inert gas and oxygen mixture can be 200 sccm, and the time can be 10 min.
[0037] During the pre-annealing process, the flow rate of the inert gas and oxygen mixture is preferably 20-100 sccm. In an embodiment of the present invention, the flow rate of the inert gas and oxygen mixture can be 30 sccm.
[0038] In this invention, the volume ratio of inert gas to oxygen in the mixture of inert gas and oxygen is preferably 100:(0.05-0.2), more preferably 100:(0.08-0.15). In an embodiment of this invention, the volume ratio of inert gas to oxygen can be 100:0.12.
[0039] In this invention, the inert gas is preferably argon.
[0040] In this invention, the pre-annealing temperature is preferably 350–480°C, more preferably 380–450°C; the holding time is preferably 5–15 min, more preferably 8–12 min; and the heating rate to the pre-annealing temperature is preferably 10–30°C / min, more preferably 15–25°C / min. In an embodiment of this invention, the pre-annealing temperature can be 450°C, the holding time can be 10 min, and the heating rate can be 20°C / min.
[0041] In this invention, the pre-annealing treatment can eliminate defects on the surface of the fluorinated mica substrate. On the other hand, it can also make the volatilization of bismuth selenide more uniform in the subsequent annealing process, thereby ensuring that bismuth selenide molecules diffuse and distribute uniformly on the substrate, thus promoting the lateral growth of bismuth selenide on the fluorinated mica substrate.
[0042] In this invention, the annealing temperature is preferably 500–700°C, more preferably 550–650°C; the holding time is preferably 10–30 min, more preferably 15–25 min; and the heating rate to the annealing temperature is preferably 30–50°C / min, more preferably 35–45°C / min. In this invention, the annealing temperature is preferably increased from the pre-annealing temperature to the annealing temperature. In embodiments of this invention, the annealing temperature can be 500°C, 600°C, or 700°C, the holding time can be 15 min, and the heating rate to the annealing temperature can be 40°C / min.
[0043] In this invention, by controlling the conditions of the pre-annealing and annealing processes within the aforementioned ranges, it is possible to further form Bi3O with large transverse dimensions. 2.5 Se2 semiconductor materials: If the pre-annealing temperature is too low, it cannot effectively eliminate the surface defects of the fluorinated mica, causing precursor molecules to be easily captured by the substrate surface defects and unable to diffuse laterally on the substrate surface effectively, resulting in a small material size; if the temperature is too high, the bismuth selenide will volatilize prematurely, causing precursor molecules to be generated prematurely during the pre-annealing process and grow on the mica substrate with surface defects, resulting in a small material size; if the pre-annealing time is too short, the treatment of the fluorinated mica substrate will be insufficient, and if the time is too long, the growth efficiency will be reduced. The annealing process controls Bi3O 2.5 The diffusion and nucleation of Se2 semiconductor material on the surface of fluorinated mica are affected by temperature variations. Too low a temperature results in a high nucleation density, while too high a temperature promotes vertical growth but weakens lateral growth. Insufficient annealing time leads to insufficient nucleation of Bi3O. 2.5 The Se2 semiconductor material was not grown sufficiently and failed to reach a thermodynamically stable state, resulting in a relatively small size; excessive growth time led to the Bi3O... 2.5 The increased nucleation density of Se2 semiconductor material leads to the Bi3O 2.5 The splicing between Se2 semiconductor materials leads to the formation of grain boundaries. Simultaneously, controlling the heating rate to the annealing temperature within the aforementioned range allows the fluorine-mica substrate to quickly reach a suitable crystal growth temperature, preventing premature volatilization of the precursor during slow heating, which could result in secondary nucleation and uneven product formation.
[0044] In this invention, the pre-annealing and annealing treatments are preferably carried out in a sealed environment, and preferably in a single-temperature zone tube furnace.
[0045] After the annealing process is completed, the present invention preferably includes sequential cooling and stopping the supply of the argon and oxygen mixture. The present invention does not impose any special limitations on the cooling process; any process well-known to those skilled in the art can be used.
[0046] This invention also provides Bi3O prepared by the preparation method described above. 2.5 Se2 semiconductor material, Bi3O 2.5 The lateral dimension of Se2 semiconductor material is >100μm;
[0047] The Bi3O 2.5 The crystal lattice structure of Se2 semiconductor material belongs to the monoclinic crystal system;
[0048] The Bi3O 2.5 The lattice parameters of Se2 semiconductor material are: β = 102.91°.
[0049] The present invention also provides the Bi3O described in the above technical solution. 2.5 Applications of Se2 semiconductor materials in electronic and optoelectronic devices. This invention does not impose any special limitations on the methods used in these applications; any methods well-known to those skilled in the art can be employed.
[0050] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0051] Example 1
[0052] like Figure 1As shown: Bismuth selenide powder (particle size 30 μm) was placed in a ceramic boat. A freshly pyrolyzed fluorinated mica substrate was placed 0.4 cm above the ceramic boat, with the pyrolyzed surface of the fluorinated mica substrate facing the direction of the bismuth selenide. The boat was then placed in the central heat source area of a single-zone tube furnace. The quartz tube of the single-zone tube furnace was sealed. Before growth began, a mixture of argon and oxygen (argon to oxygen volume ratio of 100:0.12) was introduced upstream of the quartz tube at a flow rate of 200 sccm for 10 min to purify the atmosphere of the quartz tube. The quartz tube was washed to remove impurities. Then, the flow rate of the argon and oxygen mixture was adjusted to 30 sccm. The single-temperature zone tube furnace was heated to 450°C at a rate of 20°C / min and held for 10 minutes for pre-annealing. The temperature was then increased to 500°C at a rate of 40°C / min and held for 15 minutes for annealing. The heat source was then stopped, and the furnace was allowed to cool naturally to room temperature. The supply of the argon and oxygen mixture was then stopped. The fluorinated mica substrate was removed and separated to obtain the Bi3O4. 2.5 Se2 semiconductor materials;
[0053] Figure 3 Bi3O 2.5 HRTEM images of Se2 semiconductor material in the planar and cross-sectional directions, where (a) is the Bi3O 2.5 HRTEM image of Se2 semiconductor material in the planar direction, (b) is the Bi3O 2.5 HRTEM images of Se2 semiconductor materials in the cross-sectional direction, by Figure 3 As can be seen from (a) in the figure, the Bi3O 2.5 Se2 semiconductor materials are characterized by a layered structure, consisting of... Figure 3 As can be seen from (b) in the figure, the Bi3O 2.5 The positively charged [Bi2O] in Se2 semiconductor materials 2.5 ] nn + Layers and negatively charged [BiSe2] nn - Layers are stacked alternately along the crystallographic c-axis;
[0054] Figure 4 Bi3O 2.5 TEM images and cross-sectional elemental distribution maps of Se2 semiconductor materials, where (a) is the TEM image, (b) is the Se elemental distribution map, (c) is the Bi elemental distribution map, and (d) is the O elemental distribution map. Figure 4 It can be seen that single-crystal Bi3O was successfully synthesized. 2.5 Se2.
[0055] Example 2
[0056] Referring to Example 1, the difference is that the annealing temperature is 600°C.
[0057] Example 3
[0058] Referring to Example 1, the difference is that the annealing temperature is 700°C.
[0059] Figure 2 Bi3O prepared in Examples 1-3 2.5 SEM images of Se2 semiconductor materials (scale bar: 200 μm), where (a) is the Bi3O described in Example 1. 2.5 SEM images of Se2 semiconductor materials, (b) showing the Bi3O4 semiconductor material described in Example 2. 2.5 SEM image of Se2 semiconductor material, (c) is Bi3O as described in Example 3. 2.5 SEM image of Se2 semiconductor material; by Figure 2 It can be seen that the Bi3O described in Example 1 2.5 The lateral dimension of the Se2 semiconductor material is 194.3 μm, and the Bi3O described in Example 2... 2.5 The lateral dimension of the Se2 semiconductor material is 481.9 μm, and the Bi3O described in Example 3... 2.5 The lateral dimension of the Se2 semiconductor material is 223.3 μm.
[0060] Comparative Example 1
[0061] Referring to Example 2, the difference is that a silicon oxide substrate is used to obtain Bi3O. 2.5 Se2 semiconductor materials;
[0062] Figure 5 Bi3O 2.5 SEM images of Se2 semiconductor materials, from Figure 5 It can be seen that the Bi3O 2.5 The maximum lateral dimension of Se2 semiconductor material is 24.5 μm.
[0063] Comparative Example 2
[0064] Referring to Example 2, the difference is that a c-plane sapphire substrate is used to obtain Bi3O. 2.5 Se2 semiconductor materials; Figure 6 Bi3O 2.5 SEM images of Se2 semiconductor materials, from Figure 6 It can be seen that the Bi3O 2.5 The maximum lateral dimension of Se2 semiconductor material is 9.1 μm.
[0065] Comparative Example 3
[0066] Referring to Example 1, the difference lies in the following: a single-step heating process is adopted, directly heating the single-temperature zone tube furnace to 500°C at a heating rate of 40°C / min, holding at that temperature for 15 minutes for annealing, stopping the heat source supply, and allowing it to cool naturally to room temperature. Then, the supply of the argon and oxygen mixture is stopped, the fluorine-crystal mica substrate is removed and separated to obtain the Bi3O. 2.5 Se2 semiconductor materials;
[0067] Figure 7 Bi3O 2.5 SEM images of Se2 semiconductor materials, from Figure 7 It can be seen that the Bi3O 2.5 The maximum lateral dimension of Se2 semiconductor material is 90.8 μm.
[0068] The described embodiments are merely preferred embodiments of the present invention and are not intended to limit the invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A Bi3O 2.5 The method for preparing Se2 semiconductor material is characterized by... Includes the following steps: A fluorinated mica substrate is placed on top of bismuth selenide, with the fractured surface of the fluorinated mica substrate facing the bismuth selenide. Then, under conditions of a mixture of inert gas and oxygen, pre-annealing and annealing are performed sequentially to obtain the Bi3O. 2.5 Se2 semiconductor materials; The Bi3O 2.5 The lateral dimension of Se2 semiconductor material is >100μm.
2. The preparation method according to claim 1, characterized in that, The fluorinated mica substrate is positioned 0.2–0.6 cm above the bismuth selenide.
3. The preparation method according to claim 1, characterized in that, Before performing the pre-annealing treatment, the atmosphere for the pre-annealing treatment is further washed with a mixture of inert gas and oxygen. The inert gas and oxygen mixture is introduced at a rate ≥200 sccm and for a duration >5 min.
4. The preparation method according to claim 1, characterized in that, The rate of introduction of the mixture of inert gas and oxygen is 20–100 sccm.
5. The preparation method according to claim 1, characterized in that, The pre-annealing treatment is performed at a temperature of 350–480°C for 5–15 minutes.
6. The preparation method according to claim 5, characterized in that, The heating rate to the pre-annealing temperature is 10–30 °C / min.
7. The preparation method according to claim 1, characterized in that, The annealing process is performed at a temperature of 500–700°C for 10–30 minutes.
8. The preparation method according to claim 7, characterized in that, The heating rate to the annealing temperature is 30–50 °C / min.
9. Bi3O prepared by the preparation method according to any one of claims 1 to 8 2.5 Se2 semiconductor material, characterized in that, The Bi3O 2.5 The lateral dimension of Se2 semiconductor material is >100μm; The Bi3O 2.5 The crystal lattice structure of Se2 semiconductor material belongs to the monoclinic crystal system; The Bi3O 2.5 The lattice parameters of Se2 semiconductor material are: β = 102.91°.
10. The Bi3O as described in claim 9 2.5 Applications of Se2 semiconductor materials in the fields of electronic devices and optoelectronic devices.