Preparation method of β-phase tellurium oxide nanosheet material
Through high-temperature vacuum annealing, the tellurium powder and silicon substrate were treated in an oxygen atmosphere, and high-quality β-phase tellurium oxide nanosheet materials were successfully prepared, which solved the problems of complex and high cost in the synthesis process in the prior art, and achieved efficient and low-cost preparation of the materials.
Patent Information
- Application Number
- CN202410726660.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-06
- Publication Date
- 2025-06-10
- Estimated Expiration
- 2044-06-06
AI Technical Summary
It is difficult to effectively synthesize p-type β-TeO2 materials with few layers and high mobility in the prior art, and the synthesis process is complicated and the cost is high.
A high-temperature vacuum annealing method was used to react with a tellurium powder and a silicon substrate under an oxygen atmosphere under conditions of 460-500°C, 0.05-0.15 Mpa to prepare a β-phase tellurium oxide nanosheet material.
The β-phase tellurium oxide nanosheet material is simple, efficient and low-cost preparation, and the product is characterized by high quality, high crystallinity, uniform size, regular shape, smooth surface and clear boundaries.
Smart Images
Figure CN118600541B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of novel electronic materials, and particularly relates to a preparation method of β-phase tellurium oxide nanosheet materials. Background Art
[0002] High-performance wide-bandgap oxide semiconductors will play an important role in the development of next-generation transparent electronics, power electronics, and energy-saving displays. However, the lack of high-mobility, wide-bandgap p-type semiconductors, which are necessary for the design of bipolar transistors, inverter circuits, and transparent thin-film transistors, limits their applications. Based on calculations, two-dimensional (2D) β-tellurium dioxide (β-TeO 2 ) has been proposed as a high-mobility p-type semiconductor, and developing a reliable and scalable method to synthesize few-layer, high-mobility p-type β-TeO 2 is expected to enable fast oxide electronics and transparent circuits. However, synthesizing the required layered β-TeO 2 polymorph is challenging because it forms only within a narrow temperature window and, at ambient pressure, the unwanted non-layered α- and γ-TeO 2 polymorphs dominate most of the temperature parameter space. Currently, there are few experimental reports on the synthesis of β-TeO2 in the literature. In 2021, Zavabeti et al. synthesized bilayer β-TeO2 through the surface oxidation of a eutectic mixture of tellurium and selenium. However, this experimental method is complex and the process is cumbersome.
[0003] Therefore, there is an urgent need to develop a simple, efficient, and low-cost preparation method for β-phase tellurium oxide nanosheet materials and apply it to the field of novel electronic materials. Summary of the Invention
[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a preparation method for β-phase tellurium oxide nanosheet materials that is simple, efficient, low-cost, and time-consuming. The prepared β-phase tellurium oxide nanosheet materials have uniform sizes, regular shapes, smooth surfaces, clear boundaries, and high quality and crystallinity.
[0005] Technical Solution
[0006] A preparation method of β-phase tellurium oxide nanosheet materials includes the following steps:
[0007] (1) Place tellurium powder flat at one end of a quartz boat, and then take a clean silicon substrate and cover it above the tellurium powder without contacting the tellurium powder;
[0008] (2) Send the quartz boat into the center of a high-temperature vacuum annealing furnace, introduce oxygen, and react under the conditions of 460-500 °C and 0.05-0.15 Mpa in an oxygen atmosphere. After completion, cool to room temperature to obtain a white product on the silicon substrate, which is the β-phase tellurium oxide nanosheet material.
[0009] Further, in step (1), the particle size of the tellurium powder is 30 mesh.
[0010] Further, in step (1), the distance between the top of the tellurium powder and the silicon substrate is 1 - 3 mm.
[0011] Further, in step (2), the flow rate of the oxygen is 40 - 80 sccm.
[0012] Further, in step (2), the reaction pressure is 0.1 Mpa.
[0013] Further, in step (2), the reaction time is 2 - 4 h.
[0014] Advantages of the present invention:
[0015] 1) The present invention uses tellurium powder as the source material, and after high-temperature annealing, the product β-phase tellurium oxide nanosheet material is prepared. It is the first time to prepare β-phase tellurium oxide by CVD. The diameter of the obtained β-phase tellurium oxide nanosheets is 4 - 10 μm, with good morphology, excellent crystallization performance and strong stability of the material.
[0016] 2) The β-phase tellurium oxide nanosheet material prepared by the present invention has high quality and high crystallinity, and is uniform in size, regular in shape, smooth on the surface and clear in boundary.
[0017] 3) The nanomorphology of the nanosheet material prepared by the present invention is good. At the same time, the preparation method of the tellurium nanosheet material is simple, low in cost and wide in source, and has good application prospects in the development of future transparent electronics, electronic devices and energy-saving displays. Description of the Drawings
[0018] Figure 1 It is the scanning electron microscope image of the β-phase tellurium oxide nanosheet material prepared in Example 1;
[0019] Figure 2 It is the Raman spectrum of the β-phase tellurium oxide nanosheet material prepared in Example 1;
[0020] Figure 3 It is the XRD pattern of the β-phase tellurium oxide nanosheet material prepared in Example 1;
[0021] Figure 4 It is the scanning electron microscope image of the β-phase tellurium oxide nanosheet materials prepared in Example 2 and Comparative Example 1;
[0022] Figure 5 It is the scanning electron microscope image of the β-phase tellurium oxide nanosheet materials prepared in Examples 1, 3 - 5;
[0023] Figure 6Scanning electron microscope images of the β-phase tellurium oxide nanosheet materials prepared in Comparative Example 2, Example 1, 6, and 7. Detailed implementation mode
[0024] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments.
[0025] To clearly illustrate the technical solution of the present invention, in the following embodiments, the particle size of the tellurium powder used is 30 mesh, and the purity is 99.997%; the size of the quartz boat used is: length 50 mm, width 15 mm, height 7.5 mm; the silicon substrate used is 20 mm long and 10 mm wide. But it is not limited to this.
[0026] Example 1
[0027] A preparation method of a β-phase tellurium oxide nanosheet material, comprising the following steps:
[0028] (1) Spread 60 mg of tellurium powder flat at one end of the quartz boat, and then take a clean silicon substrate and cover it above the tellurium powder but not in contact with the tellurium powder (the silicon substrate is 1-3 mm away from the top of the tellurium powder);
[0029] (2) Place the quartz boat in the center of a high-temperature vacuum annealing furnace, evacuate and introduce oxygen, the oxygen flow rate is 40 sccm, and react at 460 °C and 0.1 Mpa for 2 h in an oxygen atmosphere. After cooling to room temperature, take out the device, and the product obtained on the silicon substrate is the β-phase tellurium oxide nanosheet material.
[0030] Figure 1 The scanning electron microscope image of the β-phase tellurium oxide nanosheet material prepared in Example 1 can be seen that the prepared β-phase tellurium oxide nanosheet material has clear boundaries, uniform sizes, regular shapes, smooth surfaces, no obvious defects or impurities, and no blurred or discontinuous regions. High-quality nanosheets should exhibit good characteristics in terms of structure, morphology, and performance, which is crucial for realizing high-performance nanomaterial applications.
[0031] Figure 2 The Raman spectrum of the β-phase tellurium oxide nanosheet material prepared in Example 1. According to the Raman spectrum results, at room temperature, the characteristic vibration modes of β-phase tellurium oxide at 586 cm -1 and 666 cm -1 correspond to the Ag mode, and Raman peaks appear near 183 cm -1 , 228 cm -1 , corresponding to the B 1g and B 2g vibration modes. The sharp Raman peaks clearly show the growth of TeO in all samples 2The nanosheets have high quality and indicate that the crystal orientation is the β-phase. This shows that the Raman peaks of the β-phase tellurium oxide nanosheet material are well-behaved, which is consistent with the literature on the β-phase tellurium oxide crystal phase. Raman spectroscopy plays an important role in studying the crystallinity of wide-bandgap materials. It can reveal the interaction between the material and phonon dynamics and provides key information.
[0032] Figure 3 XRD pattern of the β-phase tellurium oxide nanosheet material prepared in Example 1. It can be seen that the nanosheets show a preferential orientation along the (100) direction, confirming the crystal structure of the β-TeO 2 lattice.
[0033] Example 2
[0034] The basic steps are the same as those in Example 1, except that the reaction temperature in step (2) is changed to 500 °C.
[0035] Comparative Example 1
[0036] The basic steps are the same as those in Example 1, except that the reaction temperature in step (2) is changed to 440 °C.
[0037] Figure 4 SEM images of the β-phase tellurium oxide nanosheet materials prepared in Example 2 and Comparative Example 1, where Figure 4 (a) is the β-phase tellurium oxide nanosheet material prepared in Comparative Example 1, Figure 4 (b) is the β-phase tellurium oxide nanosheet material prepared in Example 2. It can be seen that when the temperature is lower than 460 °C, that is, the crystallinity of the β-phase tellurium oxide nanosheet material prepared in Comparative Example 1 is poor, and unoxidized tellurium elements appear, and the product contains impurities; when the temperature reaches 500 °C, that is, the edges of the nanosheets prepared in Example 2 start to become blurred and discontinuous regions appear, with obvious defects and the crystallinity starts to deteriorate.
[0038] Example 3
[0039] The basic steps are the same as those in Example 1, except that the reaction time in step (2) is changed to 1 h.
[0040] Example 4
[0041] The basic steps are the same as those in Example 1, except that the reaction time in step (2) is changed to 3 h.
[0042] Example 5
[0043] The basic steps are the same as those in Example 1, except that the reaction time in step (2) is changed to 4 h.
[0044] Figure 5SEM images of the β-phase tellurium oxide nanosheet materials prepared in Examples 1, 3-5. Among them, Figure 5 (a) is the β-phase tellurium oxide nanosheet material prepared in Example 3, Figure 5 (b) is the β-phase tellurium oxide nanosheet material prepared in Example 1, Figure 5 (c) is the β-phase tellurium oxide nanosheet material prepared in Example 4, Figure 5 (d) is the β-phase tellurium oxide nanosheet material prepared in Example 5. It can be seen that the β-phase tellurium oxide nanosheet materials (i.e., the reaction time is 2h to 4h) prepared in Example 1, Example 4, and Example 5 not only have uniform size and shape, smooth surface, and clear boundaries, but also have strong crystallization performance and stability. When the reaction time is 1h, the reaction time is short and the number of oxidized tellurium ions is small. When the reaction time is higher than 2h, at an appropriate temperature, Te powder forms gaseous Te molecules through thermal evaporation. Subsequently, these Te molecules react with oxygen (O 2 ) in the environment to generate gaseous TeO 2 molecules. Then, in the next step, these TeO 2 molecules condense on the substrate surface, and the substrate acts as a nucleation site, promoting the formation of TeO 2 to form seeds. Therefore, according to the deposition conditions, through the chemical vapor deposition (CVD) growth mechanism, more TeO 2 molecules continuously aggregate, thus forming a TeO 2 structure that meets the expected shape.
[0045] Example 6
[0046] The basic steps are the same as those in Example 1, except that the oxygen pressure of the reaction is changed to 0.05 Mpa.
[0047] Example 7
[0048] The basic steps are the same as those in Example 1, except that the oxygen pressure of the reaction is changed to 0.15 Mpa.
[0049] Comparative Example 2
[0050] The basic steps are the same as those in Example 1, except that the oxygen pressure of the reaction is changed to 0 Mpa.
[0051] Figure 6 SEM images of the β-phase tellurium oxide nanosheet materials prepared in Comparative Example 2, Example 1, 6, and 7. Among them, Figure 6 (a) is the β-phase tellurium oxide nanosheet material prepared in Comparative Example 2, Figure 6 (b) is the β-phase tellurium oxide nanosheet material prepared in Example 6, Figure 6 (c) is the β-phase tellurium oxide nanosheet material prepared in Example 1, Figure 6(d) is the β-phase tellurium oxide nanosheet material prepared in Example 7. It can be seen that the material prepared in Example 1 (reaction pressure 0.1Mpa) is not only uniform in size and shape, but also smooth in surface, with clear boundaries, and strong in crystallization performance and stability. When the reaction pressure is 0Mpa, no nanosheets appear on the substrate, and the deposition is nanoparticle-like accumulation; when the pressure reaches 0.15Mpa, the β-tellurium oxide nanosheet undergoes obvious deformation behavior, and the originally smooth surface becomes rougher or irregular, with uneven thickness and partial collapse.
[0052] Example 8
[0053] The inventors also studied the effect of oxygen gas flow rate (0sccm, 20sccm, 40sccm, 80sccm) on the structure of the prepared materials and found that the materials prepared with a gas flow rate of 40sccm not only have uniform size and shape, smooth surface, clear boundaries, but also have strong crystallization performance and stability. When the gas flow rate is lower than 40sccm, the growth rate of the nanosheets will decrease. During the CVD process, the gas precursor needs to react with the substrate surface to deposit and form nanosheets, and too low a gas flow rate may slow down the rate of these reactions, thereby reducing the growth rate of the nanosheets; insufficient gas flow may lead to limited mass transfer on the surface of the deposit, thereby affecting the morphological uniformity of the nanosheets. This may manifest as uneven deposition on the growth surface, forming defective or non-uniform nanosheets. When the gas flow rate is higher than 80sccm, the nanosheet growth rate is too fast, the morphology is unstable, the crystal quality is reduced, and the energy consumption is increased, which is not conducive to environmental protection.
[0054] It can be seen from the above examples that the β-tellurium oxide nanosheets of the present invention have good morphology, uniform size and shape, smooth surface, clear boundaries, and strong crystallization performance and stability; at the same time, the preparation method is simple, the cost is low, and the source is wide.
Claims
1. A method for preparing a β-phase tellurium oxide nanosheet material, characterized in that: The steps include: (1) Place tellurium powder flat on one end of a quartz boat, then place a clean silicon substrate over the tellurium powder without touching it; (2) The quartz boat is sent to the center of a high-temperature vacuum annealing furnace, oxygen is introduced, and the reaction is carried out under the conditions of 460-500°C and 0.05-0.15 MPa in an oxygen atmosphere. After the reaction is completed, the reaction is cooled to room temperature to obtain a white product on a silicon substrate, which is a β-phase tellurium oxide nanosheet material. In step (1), the particle size of the tellurium powder is 30 mesh; in step (2), the flow rate of the oxygen is 40-80 sccm.
2. The method for preparing the β-phase tellurium oxide nanosheet material according to claim 1, characterized in that: In step (1), the distance between the top of the tellurium powder and the silicon substrate is 1-3 mm.
3. The method for preparing the β-phase tellurium oxide nanosheet material according to claim 1, characterized in that: In step (2), the reaction pressure is 0.1 Mpa.
4. The method for preparing the β-phase tellurium oxide nanosheet material according to any one of claims 1 to 3, characterized in that: In step (2), the reaction time is 2 to 4 h.