Bismuth selenide (BiSe) nanowire / nanobelt and preparation method thereof

Abstract

The present invention belongs to the field of inorganic material technology, and specifically relates to a bismuth selenide (BiSe) nanowire / nanobelt and a preparation method thereof. The present invention provides a preparation method for bismuth selenide (BiSe) nanowire / nanobelt, which utilizes a simple chemical vapor deposition method, uses Bi2Se3 powder and Bi powder as growth sources, uses a quartz sheet with / without Au film as a growth substrate, and is heated to a certain temperature under the condition of a rare gas as a carrier gas, and then reacts to prepare the bismuth selenide (BiSe) nanowire / nanobelt. At the same time, the obtained bismuth selenide (BiSe) nanowire / nanobelt has a regular shape and a typical one-dimensional characteristic. In addition, the preparation method of the present invention has simple steps, can be quickly prepared in large quantities, has high product purity, and has little pollution to the environment. It is easy to operate and promote, and therefore has important research value and broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic materials, and in particular relates to a bismuth selenide (BiSe) nanowire / nanobelt and a preparation method thereof. Background Art

[0002] In recent years, with the continuous development of low-dimensional materials, research has revealed that many nanostructured materials (such as two-dimensional thin films and one-dimensional nanowires) possess unique properties superior to those of bulk materials. Among them, the (Bi2)m(Bi2Se3)n (m, n are integers) series of topological insulating materials exhibits a typical layered heterostructure consisting of five atomic layers of Se-Bi-Se-Bi-Se (Bi2Se3) and a bilayer of Bi-Bi (Bi2). However, unlike Bi2Se3 (m=0, n=1), BiSe (m=1, n=2) possesses a Bi2 bilayer rather than a single five-atomic layer of repeated Bi-Se-Bi-Se-Bi. Due to its unique crystal structure and excellent electrical transport properties, it is considered a potential new near-room-temperature thermoelectric material.

[0003] For topological insulators, nanostructures with high surface areas are ideal for studying topological properties, as they minimize the influence of bulk state on surface states. Therefore, the fabrication of nanomaterials is crucial. To date, some progress has been made in the preparation of (Bi2)m(Bi2Se3)n-type topological insulating nanomaterials. For example, some studies have used molecular epitaxy to grow Bi2Se3 thin films on sapphire substrates, demonstrating smooth surface morphology and minimal height differences over a wide range of 2μm. Other studies have used thermal evaporation via the VLS mechanism to grow Bi2Se3 nanowires with diameters of approximately 410nm and lengths of 20-200μm on silicon substrates. Other studies have used vacuum thermal evaporation in a high-vacuum coating machine to grow BiSe thin films with flake-like grains approximately 500nm thick. However, most of the (Bi2)m(Bi2Se3)n-type topological insulating nanomaterials grown to date are multidimensional nanostructures, and the growth of one-dimensional BiSe nanowires / nanoribbons has yet to be reported. Moreover, because one-dimensional nanostructures have unique physical properties compared to conventionally sized materials, they are expected to further expand the range of applications of materials. Therefore, the development and growth of BiSe with typical one-dimensional characteristics has important application prospects. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a method for preparing bismuth selenide (BiSe) nanowires / nanobelts. The prepared (BiSe) nanowires / nanobelts have regular shapes and typical one-dimensional characteristics, and their physical properties are improved, thereby expanding their application range.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A first aspect of the present invention provides a method for preparing bismuth selenide (BiSe) nanowires / nanobelts, comprising the following steps:

[0007] S1. Use Bi2Se3 powder and Bi powder as growth sources, and a quartz wafer with or without Au film as the growth substrate. Then place the Bi2Se3 powder at the heating center of the reaction area of ​​the chemical vapor deposition equipment, the Bi powder upstream of the heating center, and the quartz substrate downstream of the heating center.

[0008] S2. Expel oxygen from the reaction area, then introduce a rare gas as a carrier gas, maintain the gas pressure in the reaction area within a certain range, and heat to a certain temperature to react and prepare bismuth selenide (BiSe) nanowires / nanobelts.

[0009] The present invention utilizes a simple chemical vapor deposition method, using Bi2Se3 powder and Bi powder as growth sources, and a quartz substrate with or without an Au film as the growth substrate. Under conditions where a rare gas is used as a carrier gas, the substrate is heated to a certain temperature and then reacted to produce bismuth selenide (BiSe) nanowires / nanoribbons. Whether the quartz substrate is coated with an Au film or not affects the experimental growth results. Compared to the growth results obtained on quartz substrates without an Au film, those coated with an Au film produce more numerous and denser BiSe nanowires / nanoribbons.

[0010] Preferably, in step S1, the mass ratio of the Bi2Se3 powder to the Bi powder is 1:1.

[0011] Preferably, in step S1, the Bi powder is 2 to 10 cm away from the heating center, the quartz substrate without Au film is 9 to 14 cm away from the heating center, and the quartz substrate with Au film is 9 to 11 cm away from the heating center.

[0012] More preferably, the quartz substrate without Au film coating is 9 to 12 cm away from the heating center, and the quartz substrate with Au film coating is 9 to 10 cm away from the heating center.

[0013] Preferably, in step S2, the reaction temperature is 640-680° C., and the reaction time is 0.5-6 h.

[0014] More preferably, the reaction temperature is 640-680° C., and the reaction time is 1-2 h.

[0015] Preferably, in step S2, the rare gas includes Ar gas, and the gas flow rate is controlled at 50-100 sccm.

[0016] Preferably, in step S2, the gas pressure in the reaction region is maintained below 150 Pa.

[0017] The second aspect of the present invention provides bismuth selenide (BiSe) nanowires / nanobelts prepared by the preparation method described in the first aspect.

[0018] The chemical formula of the bismuth selenide nanowire / nanobelt prepared in the present invention is BiSe, which belongs to (Bi2) m (Bi2Se3) n Compounds, wherein m = 1, n = 2. The prepared (BiSe) nanowires / nanobelts have regular shapes and typical one-dimensional characteristics. The lengths of the nanowires / nanobelts range from 10 to 300 μm and the diameters range from 200 to 800 nm. This large aspect ratio improves their physical properties, expands their application range, and has broad application prospects.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a method for preparing bismuth selenide (BiSe) nanowires / nanoribbons. Bi2Se3 powder and Bi powder are used as growth sources, and a quartz plate with or without an Au film is used as a growth substrate. After adjusting the distance between the quartz substrate and the heating center, the quartz plate is heated to a certain temperature with a rare gas as a carrier gas for reaction. The resulting (BiSe) nanowires / nanoribbons have regular shapes and typical one-dimensional characteristics. Furthermore, the resulting (BiSe) nanowires / nanoribbons have a length of 10 to 300 μm and a diameter of 200 to 800 nm. This large aspect ratio improves their physical properties, thereby expanding their application range (one-dimensional semiconductor materials with large aspect ratios can be better applied in nanoscale semiconductor devices, improving device performance). Furthermore, the present invention utilizes a chemical vapor deposition method to grow bismuth selenide (BiSe) nanowires / nanoribbons. The process is simple, easy to operate, and scalable. The product is high in purity, can be rapidly and mass-produced, and has minimal environmental pollution. Therefore, it has important research value and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 X-ray diffraction patterns of bismuth selenide (BiSe) nanowires / nanobelts of Examples 1 and 2;

[0022] Figure 2 is the X-ray diffraction pattern of Bi2Se3 of Comparative Example 1;

[0023] Figure 3 is a scanning electron micrograph of the bismuth selenide (BiSe) nanowire / nanobelt of Example 1;

[0024] Figure 4 is a scanning electron micrograph of the bismuth selenide (BiSe) nanowire / nanobelt of Example 2;

[0025] Figure 5 The scanning image and EDS spectrum of the bismuth selenide (BiSe) nanowire / nanobelt of Example 1;

[0026] Figure 6 The scanning image and EDS spectrum of the bismuth selenide (BiSe) nanowire / nanobelt of Example 2. DETAILED DESCRIPTION

[0027] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0029] Example 1

[0030] (1) Weigh 0.2 g of Bi powder and 0.2 g of Bi2Se3 powder and place them on different arks as growth sources, and place several cleaned quartz substrates without Au film on the inverted arks as growth substrates;

[0031] (2) Place the ark filled with Bi2Se3 powder at the heating center of the tube furnace of the reaction device (chemical vapor deposition equipment, instrument name: high temperature tube furnace, model: GSL-1700X, manufacturer: Hefei Kejing Material Technology Co., Ltd.), and place the ark filled with Bi powder upstream of the heating center, 3 cm away from the heating center, and place the inverted ark with the quartz substrate downstream of the heating center, with the quartz substrate 9 to 14 cm away from the heating center (9, 10, 11, 12, 13, and 14 cm respectively);

[0032] (3) Close the flange, turn on the mechanical pump to evacuate the interior of the reactor to a vacuum state, then introduce carrier gas Ar gas, adjust the gas flow rate to 70 sccm, and maintain the vacuum reading below 150 Pa;

[0033] (4) The heating rate was set to 10 °C / min, and the sample was heated to 650 °C and kept at this temperature for 2 hours. The sample was then cooled to room temperature along with the furnace. The heating switch and the gas were turned off, and the sample was taken out to obtain BiSe nanowires / nanobelts.

[0034] The bismuth selenide (BiSe) nanowires / nanobelts prepared in Example 1 were subjected to X-ray diffraction analysis. The analysis results are as follows: Figure 1As shown in Figure B1, the product has good crystallinity and obvious orientation. The main phase of the sample matches BiSe (PDF#29-0246), and the strong diffraction peaks correspond to the (005) and (0012) crystal planes, indicating that the synthesized product is of high purity.

[0035] The bismuth selenide (BiSe) nanowires / nanobelts prepared in Example 1 were analyzed by scanning electron microscopy. The analysis results are as follows: Figure 3 As shown, from Figure 3 (a) It can be found that the product length range is about 50 to 300 μm. Figure 3 (b) and (c) show that the products are nanowires (b) and nanobelts (c) with obvious one-dimensional characteristics and regular shapes.

[0036] The bismuth selenide (BiSe) nanowires / nanobelts prepared in Example 1 were subjected to electron microscopy and EDS spectrum testing. The test results are as follows: Figure 5 As shown, Figure 5 The EDS energy spectrum image and detected atomic ratio corresponding to bismuth selenide (BiSe) nanowires / nanobelts are shown. The results show that the atomic ratio of Bi to Se is 49.55:50.45, which is close to the standard atomic ratio of BiSe of 1:1.

[0037] Example 2

[0038] The preparation method is the same as that in Example 1, except that the quartz substrate without Au film treatment in Example 1 is replaced with a quartz substrate coated with Au film, and the inverted ark with the quartz substrate is placed downstream of the heating center, 9 to 11 cm (9, 10, and 11 cm, respectively) from the heating center, to grow BiSe nanowires / nanobelts.

[0039] The bismuth selenide (BiSe) nanowires / nanobelts prepared in Example 2 were subjected to X-ray diffraction analysis. The analysis results are as follows: Figure 1 As shown in B2 in the figure, it can be seen that the product has good crystallinity and obvious orientation; the main phase of the sample matches BiSe (PDF#29-0246), and the strong diffraction peaks correspond to the (005) and (0012) crystal planes, indicating that the synthesized product is of high purity.

[0040] The bismuth selenide (BiSe) nanowires / nanobelts prepared in Example 2 were analyzed by scanning electron microscopy. Figure 4 As shown, from Figure 4 (a) It can be found that the product length range is about 10 to 300 μm. Figure 4 The products (b) and (c) show distinct one-dimensional nanowires (b) and nanobelts (c), with regular shapes and Au particles at the tips. Furthermore, compared to the uncoated quartz substrate, the Au-coated quartz substrate produces a greater number of BiSe nanowires and nanobelts, which are denser and more abundant.

[0041] The bismuth selenide (BiSe) nanowires / nanobelts prepared in Example 2 were subjected to electron microscopy and EDS spectrum tests. The test results are as follows: Figure 6 As shown, Figure 6 The EDS energy spectrum image and detected atomic ratio corresponding to bismuth selenide (BiSe) nanowires / nanobelts are shown. The results show that the atomic ratio of Bi to Se is 49.26:50.74, which is close to the standard atomic ratio of BiSe of 1:1.

[0042] Comparative Example 1

[0043] The preparation method is the same as that of Examples 1 and 2, except that the growth sources in Examples 1 and 2 are replaced with Bi2Se3 powder only without Bi powder, which is used to set up a control group for comparison. Other conditions are the same.

[0044] The product prepared in Comparative Example 1 was subjected to X-ray diffraction analysis, and the analysis results are as follows: Figure 2 As shown, B1 is the product generated without Au plating, and B2 is the product generated by Au plating. It can be seen that the main phase of the samples matches Bi2Se3 (PDF#33-0214), and the strong diffraction peaks correspond to the (006) and (0015) crystal planes. The results show that the generated products are all Bi2Se3, not BiSe.

[0045] Comparative Example 2

[0046] The preparation method was the same as that in Example 1, except that the distance between the quartz substrate and the heating center in Example 1 was changed to 3-8 cm and 15-20 cm (3, 4, 5, 6, 7, 8 cm and 15, 16, 17, 18, 19, 20 cm, respectively) for setting up a control group for comparison. Other conditions were the same.

[0047] The results show that when the quartz substrate is 3 to 8 cm away from the heating center, almost no product is generated; when the distance from the heating center is 15 to 20 cm, the product shape is mostly blocky, and no nanowires / nanobelts are generated.

[0048] Comparative Example 3

[0049] The preparation method was the same as that in Example 2, except that the distance between the quartz substrate and the heating center in Example 2 was changed to 3-8 cm and 12-17 cm (3, 4, 5, 6, 7, 8 cm and 12, 13, 14, 15, 16, 17 cm, respectively) for setting up a control group for comparison. Other conditions were the same.

[0050] The results show that when the quartz substrate is 3 to 8 cm away from the heating center, almost no product is generated; when the distance from the heating center is 12 to 17 cm, the generated product becomes Bi2Se3.

[0051] Comparative Example 4

[0052] The preparation method is the same as that of Examples 1 and 2, except that the reaction temperatures in Examples 1 and 2 are changed to 620, 630°C and 690, 700°C, respectively, for setting up control groups for comparison, and other conditions are the same.

[0053] The results show that when the reaction temperature is 620-630℃, the growth effect is poor and there are almost no nanowires / nanobelts in the product; when the reaction temperature is 690-700℃, the product shapes are mostly large towers and blocks.

[0054] Comparative Example 5

[0055] The preparation method is the same as that of Examples 1 and 2, except that the gas flow rate in Examples 1 and 2 is changed to 50 sccm respectively, which is used to set up a control group for comparison, and other conditions are the same.

[0056] The results show that although the growth effect is slightly different, the product is still BiSe.

[0057] Comparative Example 6

[0058] The preparation method is the same as that of Examples 1 and 2, except that the gas flow rate in Examples 1 and 2 is changed to 100 sccm respectively for setting up a control group for comparison, and other conditions are the same.

[0059] The results show that although the growth effect is slightly different, the product is still BiSe.

[0060] Comparative Example 7

[0061] The preparation method is the same as that of Examples 1 and 2, except that the reaction time in Examples 1 and 2 is changed to 30 min respectively, which is used to set up a control group for comparison. Other conditions are the same.

[0062] The results show that although the growth effects are slightly different, the product is still BiSe.

[0063] Comparative Example 8

[0064] The preparation method is the same as that of Examples 1 and 2, except that the reaction time in Examples 1 and 2 is changed to 6 h respectively for setting up a control group for comparison, and other conditions are the same.

[0065] The results show that although the growth effect is slightly different, the product is still BiSe.

[0066] In summary, the present invention utilizes a simple chemical vapor deposition method, using Bi2Se3 powder and Bi powder as growth sources, a quartz plate with / without Au film as a growth substrate, and heating to a certain temperature under the condition of a rare gas as a carrier gas to prepare a bismuth selenide (BiSe) nanowire / nanobelt through reaction. The prepared (BiSe) nanowire / nanobelt has a regular shape and typical one-dimensional characteristics. The length of the nanowire / nanobelt is 10 to 300 μm and the diameter is 200 to 800 nm. This large aspect ratio improves its physical properties, expands its application range, and has broad application prospects.

[0067] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A method for preparing bismuth selenide (BiSe) nanowires / nanobelts, characterized in that: The following steps are involved: S1. Using Bi2Se3 powder and Bi powder as growth sources and a quartz wafer with or without an Au film as a growth substrate, the Bi2Se3 powder is placed at the heating center of the reaction area of ​​a chemical vapor deposition apparatus, the Bi powder is placed upstream of the heating center, and the quartz substrate is placed downstream of the heating center; the mass ratio of the Bi2Se3 powder to the Bi powder is 1:1, the Bi powder is 2-10 cm away from the heating center, the quartz substrate without an Au film is 9-14 cm away from the heating center, and the quartz substrate with an Au film is 9-11 cm away from the heating center; S2. Expel oxygen from the reaction area, then introduce a rare gas as a carrier gas, maintain the gas pressure in the reaction area within a certain range, and heat to a certain temperature to react and prepare bismuth selenide BiSe nanowires / nanobelts.

2. The method for preparing bismuth selenide (BiSe) nanowires / nanobelts according to claim 1, characterized in that: The distance between the quartz substrate without Au film and the heating center was 9~12 cm, and the distance between the quartz substrate with Au film and the heating center was 9~10 cm.

3. The method for preparing bismuth selenide (BiSe) nanowires / nanobelts according to claim 1, wherein: In step S2, the reaction temperature is 640-680° C., and the reaction time is 0.5-6 h.

4. The method for preparing bismuth selenide (BiSe) nanowires / nanobelts according to claim 3, characterized in that: The reaction temperature is 640~680℃ and the reaction time is 1~2 h.

5. The method for preparing bismuth selenide (BiSe) nanowires / nanobelts according to claim 1, wherein: In step S2, the rare gas includes Ar gas, and the gas flow rate is controlled at 50-100 sccm.

6. The method for preparing bismuth selenide (BiSe) nanowires / nanobelts according to claim 1, characterized in that: In step S2, the gas pressure in the reaction region is maintained below 150 Pa.

7. Bismuth selenide (BiSe) nanowires / nanobelts prepared by the preparation method according to any one of claims 1 to 6.

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