Preparation method of tellurium nanowire and tellurium nanowire

Abstract

The invention provides a preparation method of a tellurium nanowire and the tellurium nanowire, and relates to the technical field of semiconductors. The preparation method comprises the following steps: S1, providing a clean substrate; s2, transferring the substrate in the step S1 into a molecular beam epitaxy (MBE) pretreatment chamber for degassing treatment; s3, transferring the substrate in the step S2 into a molecular beam epitaxy (MBE) growth chamber for deoxidation treatment; s4, cooling the substrate in the step S3 to a growth temperature; s5, adjusting the tellurium source beam to a growth value, and growing tellurium nanowires on the substrate in the step S4; wherein the steps S3-S5 are completed under the monitoring of high-energy electron diffraction; the substrate in the steps S3 to S5 is in a rotating state; the steps S1 to S5 are carried out in a vacuum environment. According to the preparation method provided by the invention, the preparation of the tellurium nanowire array which is large in area, high in purity and uniform in forming can be realized.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a tellurium nanowire and the tellurium nanowire. Background Art

[0002] Tellurium is a narrow bandgap elemental semiconductor. Its bandgap width gradually increases as the thickness of the material decreases. The bandgap width of three-dimensional bulk materials is 0.34 eV, and the bandgap width of single-atomic layer materials will increase to 1 eV. Tellurium has potential applications in optoelectronics, thermoelectrics, piezoelectrics, catalysis, chemical sensing, field emission and other fields. One-dimensional nanowires and nanosheets have unique geometric structures and properties, and are ideal materials for the development of new nanodevices in the future. The controllable preparation of large-area uniform nanowires is the basis for their large-scale application, and it is also a challenge that nanowire preparation has always faced.

[0003] Tellurium has a unique chain crystal structure. Adjacent tellurium atoms on the same chain are connected by covalent bonds, while parallel adjacent chains are bound by van der Waals forces. This anisotropic atomic arrangement makes it easier for tellurium to form a one-dimensional structure. In related technologies, large-sized sheet-like tellurium nanowires can be prepared by solution methods, and the nanowires can be flattened on substrates such as silicon oxide by transfer; gas phase transport is also used to prepare tellurium nanowires. Tellurium powder is usually placed at the high-temperature end of a quartz tube, and the tellurium powder is vaporized at high temperature as a tellurium source. Inert gases such as argon are used as carrier gases to transport the tellurium source to the low-temperature end substrate to form nanowires. The morphology, size, growth direction, etc. of the nanowires prepared by this method are closely related to the growth process. The above two methods are prone to introduce impurities into tellurium nanowires due to growth environment limitations, and the uniformity of the nanowires is difficult to ensure due to the different growth environments of the nanowires in the reactor and at different positions on the substrate. Therefore, the preparation of large-area, high-purity, and uniformly formed tellurium nanowire materials is still difficult with current technology. Summary of the invention

[0004] Based on the above problems, the present invention provides a method for preparing tellurium nanowires and tellurium nanowires, so as to realize the preparation of large-area, high-purity and uniformly formed tellurium nanowire arrays.

[0005] A first aspect of the present invention provides a method for preparing tellurium nanowires, the method comprising the following steps:

[0006] S1. Provide a clean substrate;

[0007] S2, transferring the substrate described in step S1 into a molecular beam epitaxy MBE pretreatment chamber for degassing;

[0008] S3, transferring the substrate described in step S2 into a molecular beam epitaxy (MBE) growth chamber for deoxidation treatment;

[0009] S4, cooling the substrate in step S3 to a growth temperature;

[0010] S5, adjusting the tellurium source beam to a growth value, and growing tellurium nanowires on the substrate in step S4;

[0011] Wherein, the step S3 and the step S5 are completed under high energy electron diffraction monitoring; the substrate in the step S3 and the step S5 is in a rotating state; the steps S1 to S5 are performed in a vacuum environment;

[0012] The tellurium source beam is a tellurium single substance source beam, and the growth value of the tellurium single substance source beam is 1x10 -7 -1x10 -5 Torr, and the growth temperature is -200°C to 200°C.

[0013] In some embodiments, the substrate includes at least one of gallium arsenide, germanium, and mica.

[0014] In some embodiments, during the degassing process, the degassing temperature is 100° C.-400° C., and the degassing time is 0.5 hour-5 hours.

[0015] In some embodiments, during the deoxidation treatment, the deoxidation temperature is 200° C.-1000° C., and the deoxidation time is 0.1 hour-2 hours.

[0016] In some embodiments, the growth temperature is 25°C to 200°C.

[0017] In some embodiments, the growth value is 1x10 -7 Torr-5x10 -6 Torr.

[0018] In some embodiments, the growth time of the tellurium nanowires grown on the substrate in step S4 is 0.1 minutes to 1000 minutes, preferably 1 minute to 100 minutes.

[0019] In some embodiments, the substrate in step S5 is in a rotating state, and the rotation speed is 1 rpm to 60 rpm, preferably 6 rpm to 20 rpm.

[0020] The second aspect of the present invention provides a tellurium nanowire, which is prepared by the method for preparing the tellurium nanowire described in the first aspect of the present invention.

[0021] In some embodiments, the average length of the tellurium nanowires is 100 nm to 10000 nm;

[0022] In some embodiments, the density of the tellurium nanowires is 1x10 8 / cm-2 -1x10 10 / cm -2 .

[0023] Through the above technical solution, the present invention has at least the following beneficial effects compared with the prior art:

[0024] (1) The preparation method of tellurium nanowires provided by the present invention utilizes molecular beam epitaxy (MBE) to grow in a high vacuum environment, which can effectively reduce the impurity content of the nanowire array and improve the purity of the tellurium nanowires;

[0025] (2) In the method for preparing tellurium nanowires provided by the present invention, the substrate is in a rotating state, which can effectively improve the large-area uniformity of the nanowire array and is conducive to the uniform growth of tellurium nanowires;

[0026] (3) The method for preparing tellurium nanowires provided by the present invention can significantly improve the controllability of the vertical growth of tellurium nanowires, and enhance the growth uniformity and molding quality of tellurium nanowires by using high energy electron diffraction monitoring (RHEED) facilities and other means of detection;

[0027] (4) The method for preparing tellurium nanowires provided by the present invention is highly repeatable, simple and easy to implement, and can easily realize the industrial production of tellurium nanowires. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Shown is a schematic flow chart of the method for preparing tellurium nanowires provided by the present invention.

[0029] Figure 2 Shown are a top view and a side view of the morphology of tellurium nanowires grown on a germanium substrate in one embodiment of the present invention.

[0030] Figure 3 Shown are a top view and a side view of the morphology of tellurium nanowires grown on a mica substrate according to an embodiment of the present invention.

[0031] Figure 4 Shown are a top view and a side view of the morphology of tellurium nanowires grown at a growth time of 20 minutes in one embodiment of the present invention.

[0032] Figure 5 The growth value of the tellurium source beam in one embodiment of the present invention is adjusted to 3.7x10 -7 Top and side views of the morphology of Torr-grown tellurium nanowires.

[0033] Figure 6 Shown are the top view and side view of the morphology of tellurium nanowires grown at a growth temperature of 225° C. in a comparative example of the present invention.

[0034] Figure 7The figure shows the growth value of the tellurium source beam at a growth temperature of 225°C in a comparison of the present invention, which is adjusted to 2.3x10 -7 Top view of the morphology of Torr-grown tellurium nanowires. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] As introduced in the background technology, many studies have achieved the preparation of tellurium nanowires. However, due to different preparation methods, the growth results of tellurium nanowires vary greatly.

[0037] In some related technologies, large-sized sheet-like tellurium nanowires can be prepared by solution method. This method puts a compound solution containing Te into a hydrothermal reactor to generate tellurium nanowires through chemical reaction. Subsequently, the tellurium nanowires are separated from the waste liquid by centrifugal force, and the impurities on the nanowires are washed away with deionized water. The nanowires can be transferred to substrates such as silicon oxide, but the tellurium nanowires prepared by this technology have poor uniformity. Generally, the nanowires are transferred to other substrates by spin coating a solution containing nanowires, and most of the nanowires lie flat on the substrate; tellurium nanowires can also be prepared by gas phase transport method. Tellurium powder is usually placed at the high temperature end of the quartz tube, and the tellurium powder is vaporized by high temperature as a tellurium source. The tellurium source is transported to the low temperature end substrate using an inert gas such as argon as a carrier gas to form nanowires. The morphology, size, growth direction, etc. of the nanowires prepared by this method are closely related to the growth process. By regulating the growth process, various forms of nanostructures growing horizontally or vertically can be obtained. In this technology, the substrate is usually in a static state. For large-area samples, the different temperatures and source concentrations at different positions on the substrate can easily lead to uneven samples. In addition, the above two methods are prone to introduce impurities into tellurium nanowires due to growth environment restrictions, and are not suitable for the preparation of high-purity nanowires.

[0038] In summary, due to the limitations of preparation methods, production equipment and other factors, the current preparation technology of tellurium nanowires cannot achieve wafer-level, ultra-high purity, high-density, and uniform vertical tellurium nanowire preparation.

[0039] In view of the above technical problems, the present invention provides a method for preparing tellurium nanowires, which comprises the following steps:

[0040] S1. Provide a clean substrate;

[0041] S2, transferring the substrate described in step S1 into a molecular beam epitaxy MBE pretreatment chamber for degassing;

[0042] S3, transferring the substrate described in step S2 into a molecular beam epitaxy (MBE) growth chamber for deoxidation treatment;

[0043] S4, cooling the substrate in step S3 to a growth temperature;

[0044] S5, adjusting the tellurium source beam to a growth value, and growing tellurium nanowires on the substrate in step S4;

[0045] Wherein, the step S3 and the step S5 are completed under high energy electron diffraction monitoring; the substrate in the step S3 and the step S5 is in a rotating state; the steps S1 to S5 are performed in a vacuum environment;

[0046] The tellurium source beam is a tellurium single substance source beam, and the growth value of the tellurium single substance source beam is 1x10 -7 -1x10 -5 Torr, and the growth temperature is -200°C to 200°C.

[0047] Figure 1 FIG. 4 is a schematic diagram of the process for preparing tellurium nanowires provided by the present invention. Figure 1 As shown, the method for preparing tellurium nanowires provided by the present invention comprises the following steps:

[0048] S1. Provide a clean substrate;

[0049] Specifically, the substrate includes at least one of gallium arsenide, germanium, and mica, and there is no clear limitation on the crystal orientation, doping degree, etc. of the substrate.

[0050] S2, transferring the substrate described in step S1 into a molecular beam epitaxy MBE pretreatment chamber for degassing;

[0051] The substrate is introduced into the molecular beam epitaxy MBE pretreatment chamber for degassing treatment to remove water vapor and other gases adsorbed on the surface of the substrate.

[0052] In some embodiments, during the degassing treatment, the degassing temperature is 100°C-400°C, for example, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C or 400°C; the degassing time is 0.5 hour-5 hours, for example, 0.5 hour, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours.

[0053] S3, transferring the substrate described in step S2 into a molecular beam epitaxy (MBE) growth chamber for deoxidation treatment;

[0054] The substrate is introduced into the molecular beam epitaxy (MBE) growth chamber for deoxidation treatment. The deoxidation temperature and time are related to the specific type of substrate selected. During the deoxidation process, the oxide layer on the surface of the substrate will be removed under high temperature conditions, so the specific time of the deoxidation temperature is related to the type of substrate. The fresh surface of the substrate after deoxidation can reduce impurities in the material and better induce the epitaxial growth of the material to effectively reduce the impurity content of the nanowire array. Moreover, the molecular beam epitaxy (MBE) method grows in a high vacuum environment, which can further reduce the impurity content of the nanowire array and greatly improve the purity of the tellurium nanowires.

[0055] In some embodiments, during the deoxidation treatment, the deoxidation temperature is 200° C.-1000° C., and the deoxidation time is 0.1 hour-2 hours.

[0056] In some embodiments, the substrate is a germanium substrate, and during the deoxidation treatment, the deoxidation temperature is 400° C.-500° C., and the deoxidation time is 0.1 hour-2 hours.

[0057] In some embodiments, the substrate is a gallium arsenide substrate, and during the deoxidation treatment, the deoxidation temperature is 500° C.-700° C., and the deoxidation time is 0.1 hour-2 hours.

[0058] In some embodiments, the substrate is a mica substrate, and during the deoxidation treatment, the deoxidation temperature is 300° C.-600° C., and the deoxidation time is 0.1 hour-2 hours.

[0059] S4, cooling the substrate in step S3 to a growth temperature;

[0060] Since the growth temperature of tellurium nanowires is lower than the deoxidation temperature of the substrate, the substrate temperature needs to be lowered to the growth temperature after the substrate is deoxidized.

[0061] In some embodiments, the growth temperature is -200°C to 200°C, for example -200°C, -190°C, -180°C, -170°C, -160°C, -150°C, -140°C, -130°C, -120°C, -110°C, -100°C, -90°C, -80°C, -70°C, -60°C, -50°C, -40°C, -30°C, -20°C, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C. Growth temperature is a key influencing factor for tellurium nanowires. When the tellurium source beam current remains unchanged, lowering the temperature is more conducive to the vertical growth of tellurium nanowires and increasing the density of nanowires, but it may lead to a decrease in the quality of nanowire crystals. On the contrary, increasing the growth temperature will reduce the density of nanowires, and too high a temperature may even prevent the nanowires from growing vertically.

[0062] In a preferred embodiment, the growth temperature is 25°C to 200°C. When the growth temperature is lower than 25°C (room temperature), it is necessary to add refrigeration equipment to the growth system, or use other methods to cool down, which increases the cost and is not suitable for large-scale industrial production. However, when the growth temperature is too high, the nanowire morphology may be unstable or other defects may occur, and even the nanowire may not grow vertically.

[0063] S5, adjusting the tellurium source beam to a growth value, and growing tellurium nanowires on the substrate in step S4;

[0064] When not in use, the beam current of the source is usually set very low. Before the tellurium nanowires are grown, the beam current of the tellurium source is adjusted to a growth value. In some embodiments, the growth value is 1x10 -7 -1x10 -5 Torr, for example, 1x10 -7 , 2x10 -7 , 3x10 -7 , 4x10 -7 , 5x10 -7 , 6x10 -7 , 7x10 -7 , 8x10 -7 , 9x10 -7 , 1x10 -6 , 2x10 -6 , 3x10 -6 , 4x10 -6 , 5x10 -6 , 6x10 -6 , 7x10 -6 , 8x10 -6 , 9x10-6 , 1x10 -5 The tellurium source beam current is a key parameter for the growth of nanowires. While maintaining the growth temperature unchanged, increasing the tellurium source beam current can increase the density and size of the nanowires.

[0065] In a preferred embodiment, the growth value is 1x10 -7 Torr-5x10 -6 Torr.

[0066] Specifically, in step S5, after the tellurium source beam is adjusted to the growth value, the main baffle is opened to start the growth of tellurium nanowires; after the tellurium nanowires grow to the target length, the tellurium source beam and the main baffle are closed to end the growth; finally, the temperature is lowered to room temperature; thus, the preparation of tellurium nanowires is completed.

[0067] Wherein, the steps S3 and S5 are completed under the monitoring of high energy electron diffraction (RHEED); specifically, the deoxidation treatment of the substrate and the growth process of the tellurium nanowires are both carried out under the monitoring of RHEED. This is because RHEED is a device unique to the molecular beam epitaxy MBE system for observing the surface state of the sample. RHEED monitors the process of substrate deoxidation treatment and tellurium nanowire growth in real time, and can more accurately control the substrate deoxidation and the growth direction of the tellurium nanowires and the forming uniformity of the tellurium nanowires, which can significantly improve the controllability of the vertical growth of the tellurium nanowires, thereby improving the growth uniformity and forming quality of the tellurium nanowires.

[0068] In the present invention, during the process of high energy electron diffraction (RHEED) monitoring step S3, during the deoxidation process of the substrate, RHEED can monitor the removal of oxides on the substrate surface in real time. The change of the RHEED diffraction pattern can reflect the removal degree of oxides on the substrate surface and the surface flatness. When the diffraction pattern shows a clear stripe pattern, it indicates that the deoxidation of the substrate surface is completed and the atoms are arranged in an orderly and flat manner.

[0069] In the present invention, during the process of high energy electron diffraction (RHEED) monitoring of step S5, the growth state, crystal structure and surface morphology of the tellurium nanowire can be monitored in real time, and by analyzing the changes in the RHEED diffraction pattern, the nucleation, growth rate and crystal quality of the tellurium nanowire can be better regulated. This is crucial for optimizing the growth parameters to improve the quality of the tellurium nanowire; and by further combining the appropriate growth temperature and beam growth value design of the tellurium nanowire, a large range of control of the size and density of the tellurium nanowire can be achieved, and a vertical tellurium nanowire array with a large area can be prepared, and the purity is high and the uniformity is good.

[0070] The substrate in step S3 and step S5 is in a rotating state; specifically, the substrate is in a rotating state during the deoxidation treatment of the substrate and the growth process of the tellurium nanowires. By rotating the substrate, the uniformity of the substrate surface temperature and source concentration can be enhanced, thereby effectively improving the large-area uniformity of the nanowire array, which is conducive to the uniform growth of the tellurium nanowires.

[0071] In some embodiments, the substrate in step S5 is in a rotating state, and the rotation speed is 1 circle / minute-60 circles / minute, for example, 1 circle / minute, 2 circles / minute, 3 circles / minute, 4 circles / minute, 5 circles / minute, 6 circles / minute, 7 circles / minute, 8 circles / minute, 9 circles / minute, 10 circles / minute, 15 circles / minute, 20 circles / minute, 25 circles / minute, 30 circles / minute, 35 circles / minute, 40 circles / minute, 45 circles / minute, 50 circles / minute, 55 circles / minute, and 60 circles / minute.

[0072] In a preferred embodiment, the rotation speed is 6 rpm to 20 rpm.

[0073] Wherein, the steps S1 to S5 are performed in a vacuum environment; the deoxidation treatment and the growth of the tellurium nanowires are performed in a high vacuum environment, which is helpful to improve the purity of the tellurium nanowire array.

[0074] The tellurium source beam is a tellurium single substance source beam. The present invention uses tellurium single substance as the tellurium source, which has high purity. Compared with the compound tellurium source, the high-purity single substance tellurium source is not easy to introduce other element impurities, further improving the purity of the tellurium nanowires.

[0075] In addition, the method for preparing tellurium nanowires provided by the present invention has high repeatability, is simple and easy to implement, and is easy to realize the industrial production of tellurium nanowires.

[0076] In some embodiments, the substrate includes at least one of gallium arsenide, germanium, and mica.

[0077] Substrate cleanliness is the basis for preparing high-quality tellurium nanowires. If the substrate is a no-clean substrate, it can be directly transferred into the molecular beam epitaxy MBE pretreatment chamber. If the substrate is not a no-clean substrate, the substrate surface must be cleaned and blown dry with a nitrogen gun.

[0078] In some embodiments, during the degassing process, the degassing temperature is 100-400 degrees, and the degassing time is 0.5 hours-5 hours. The purpose is to remove water vapor and other gases adsorbed on the surface of the substrate. Degassing can minimize the contamination of the substrate to the molecular beam epitaxy MBE growth chamber and the growth material.

[0079] In some embodiments, the degassed substrate needs to be introduced into a molecular beam epitaxy (MBE) growth chamber for deoxidation. The quality of deoxidation can be determined by RHEED. The fresh surface of the substrate after deoxidation can reduce impurities in the material and better induce epitaxial growth of the material.

[0080] In some embodiments, the growth time of the tellurium nanowires grown on the substrate in step S4 is 0.1 minutes to 1000 minutes, preferably 1 minute to 100 minutes.

[0081] The second aspect of the present invention provides a tellurium nanowire, which is prepared by the method for preparing the tellurium nanowire described in the first aspect of the present invention.

[0082] In some embodiments, the average length of the tellurium nanowire is 100nm-10000nm, for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 2000nm, 3000nm, 4000nm, 5000nm, 6000nm, 7000nm, 8000nm, 9000nm, 10000nm. The average length of the tellurium nanowire of the present invention can be measured by observing the electron microscope morphology of the tellurium nanowire. The average length of the tellurium nanowire is related to the growth value of the tellurium source beam, the growth temperature and the growth time.

[0083] In some embodiments, the density of the tellurium nanowires is 1x10 8 / cm -2 -1x10 10 / cm -2 , for example 1x10 8 / cm -2 , 2x10 8 / cm -2 , 3x10 8 / cm -2 , 4x10 8 / cm -2 , 5x10 8 / cm -2 , 6x10 8 / cm -2 , 7x10 8 / cm -2 , 8x10 8 / cm -2 , 9x10 8 / cm -2 , 1x10 9 / cm -2 , 2x10 9 / cm -2 , 3x10 9 / cm -2 , 4x10 9 / cm -2 , 5x10 9 / cm -2 , 6x10 9 / cm -2 , 7x10 9 / cm -2 , 8x10 9 / cm -2 , 9x10 9 / cm -2 , 1x10 10 / cm -2 The density of tellurium nanowires was tested by using a scanning electron microscope (SEM) to image the tellurium nanowire growth array sample and selecting a representative area (100 μm 2 ), and use image analysis software to calculate the number of nanowires in the area. In order to improve accuracy, multiple different areas should be selected for statistics and the average value should be taken. The tellurium nanowire array prepared by the present invention grows uniformly and vertically, and has high growth quality.

[0084] The present invention will be described in further detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0085] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0086] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0087] Example 1

[0088] The specific steps of the method for preparing tellurium nanowires are as follows:

[0089] Step 1, stick the clean germanium substrate on the molybdenum support and introduce it into the molecular beam epitaxy MBE pretreatment chamber, and degas at 400°C for 1 hour.

[0090] Step 2, the degassed germanium substrate is introduced into the molecular beam epitaxy MBE growth chamber, deoxidized at 550°C for half an hour, and the substrate is cooled to 150°C.

[0091] Step 3: Adjust the tellurium source beam pressure to 1.2x10 -6 Torr, after the beam is stable, open the main baffle and start growth.

[0092] Step 4, the growth time is 60 minutes, and the main baffle and the tellurium source beam main baffle are closed.

[0093] Step 5: Cool the substrate to room temperature.

[0094] in, Figure 2 The top view (Fig. (a)) and the side view (Fig. (b)) of the tellurium nanowires grown on the germanium substrate in Example 1 are shown. The density of the tellurium nanowires can be measured by the top view (Fig. (a)) and the length of the tellurium nanowires can be measured by the side view (Fig. (b)). Specifically, Figure 2 The length of the tellurium nanowires is 2.925 μm and the density of the tellurium nanowires is 2.5x10 9 / cm 2 .

[0095] Example 2

[0096] This embodiment is prepared by referring to the preparation method of embodiment 1, the only difference being that the germanium substrate is replaced by a mica substrate.

[0097] in, Figure 3 The top view (Fig. (a)) and side view (Fig. (b)) of the tellurium nanowires grown on the mica substrate in Example 2 of the present invention are shown. Specifically, Figure 3 The length of the tellurium nanowires is 3 μm and the density of the tellurium nanowires is 1.6x10 9 / cm 2 .

[0098] According to Example 1 and Example 2, high-density vertically grown tellurium nanowires are also grown on mica substrates. The average length of the tellurium nanowires is about 3 μm, but the density of the tellurium nanowires is slightly lower. The distribution uniformity of the tellurium nanowires on both substrates is relatively excellent. The tellurium nanowires grown on the mica substrate are slightly inferior to the tellurium nanowires grown on the germanium substrate.

[0099] Example 3

[0100] This example is prepared by referring to the preparation method of Example 1, with the only difference being that the growth time of the tellurium nanowires is changed; specifically, the growth time is set to 20 minutes.

[0101] in, Figure 4The figures show the top view (Fig. (a)) and the side view (Fig. (b)) of the tellurium nanowires grown in an embodiment of the present invention at a growth time of 20 minutes. Specifically, Figure 4 The length of the tellurium nanowires is 1.172 μm and the density of the tellurium nanowires is 8x10 9 / cm 2 .

[0102] According to Example 1 and Example 3, the top view and side view of the tellurium nanowires grown for 60 minutes show that the length of the tellurium nanowires is 2.925 μm, which is longer than that of the 20-minute growth time, and the density is 2.5x10 9 / cm 2 Compared with 20 minutes, it has decreased. It can be seen that the length of tellurium nanowires is basically proportional to the growth time, and as the growth time increases, the density of tellurium nanowires will decrease. This is because some tellurium nanowires have not grown, and the number of longer tellurium nanowires will be relatively reduced, so the density will decrease.

[0103] Example 4

[0104] This comparative example was prepared by referring to the preparation method of Example 3, except that the tellurium source beam current was changed. Specifically, the tellurium source beam current for growing tellurium nanowires was adjusted to 3.7×10 -7 Torr.

[0105] in, Figure 5 The growth value of the tellurium source beam in one embodiment of the present invention is adjusted to 3.7x10 -7 Top view (a) and side view (b) of the morphology of Torr-grown tellurium nanowires.

[0106] According to Example 3 and Example 4, when the tellurium source beam current of the tellurium nanowire is increased from 1.2x10 -6 Torr reduced to 3.7x10 -7 Torr, the density of tellurium nanowires is 8x10 9 / cm 2 Down to 5x10 9 / cm 2 , the length decreased from 1.172μm to 0.52μm. By comparison, it can be found that reducing the tellurium source beam current of tellurium nanowires will cause the density and length of nanowires to decrease, and the tellurium nanowires will be slightly skewed and the edges of the tellurium nanowires will be slightly bent, but most of the tellurium nanowires can grow vertically.

[0107] Comparative Example 1

[0108] This comparative example was carried out with reference to the preparation method of Example 1, the only difference being that the growth temperature of the tellurium nanowires was changed; specifically: the growth time was set to 225°C.

[0109] in, Figure 6 Shown are the top view (Figure (a)) and side view (Figure (b)) of the tellurium nanowires grown at a growth temperature of 225°C in a comparative example of the present invention. Figure 6 The length of the tellurium nanowires is 1.2 μm, and the density of the tellurium nanowires is 1.2x10 9 / cm 2 .

[0110] By comparing Example 1 and Comparative Example 1, it can be found that the increase in growth temperature is not conducive to the vertical growth of tellurium nanowires, some tellurium nanowires appear obviously skewed, the tellurium nanowires become wider, the density decreases, and the edges of the tellurium nanowires appear obviously bent.

[0111] Comparative Example 2

[0112] This comparative example was prepared by referring to the preparation method of comparative example 1, except that the tellurium source beam current was changed. Specifically, the tellurium source beam current for growing tellurium nanowires was adjusted to 2.3×10 -7 Torr.

[0113] in, Figure 7 The figure shows that the growth value of the tellurium source beam is adjusted to 2.3x10 -7 Top view of the morphology of Torr-grown tellurium nanowires.

[0114] According to Comparative Examples 1 and 3, the growth temperature is 225°C, and when the tellurium source beam current of the tellurium nanowire is 1.2x10 -6 Torr reduced to 2.3x10 -7 Torr, e.g. Figure 7 As shown in the top view, the tellurium nanowires can no longer grow vertically and are lying flat, and their density is greatly reduced. In Comparative Example 2, the growth morphology of the tellurium nanowires is affected by two factors: the growth temperature and the growth value of the tellurium source beam. The growth value of the tellurium source beam is small and the growth temperature is too high at the same time, which seriously affects the normal growth of the tellurium nanowires, thereby causing the growth quality of the tellurium nanowires to be greatly reduced.

[0115] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing tellurium nanowires, characterized in that: The preparation method comprises the following steps: S1. Provide a clean substrate; S2, transferring the substrate described in step S1 into a molecular beam epitaxy MBE pretreatment chamber for degassing; S3, transferring the substrate described in step S2 into a molecular beam epitaxy (MBE) growth chamber for deoxidation treatment; S4, cooling the substrate in step S3 to a growth temperature; S5, adjusting the tellurium source beam to a growth value, and growing tellurium nanowires on the substrate in step S4; Wherein, the step S3 and the step S5 are completed under high energy electron diffraction monitoring; the substrate in the step S3 and the step S5 is in a rotating state; the steps S1 to S5 are performed in a vacuum environment; The tellurium source beam is a tellurium single substance source beam, and the growth value of the tellurium single substance source beam is 1x10 -7 -1x10 -5 Torr, and the growth temperature is -200°C to 200°C.

2. The method for preparing tellurium nanowires according to claim 1, characterized in that: The substrate includes at least one of gallium arsenide, germanium, and mica.

3. The method for preparing tellurium nanowires according to claim 1, characterized in that: During the degassing process, the degassing temperature is 100° C.-400° C., and the degassing time is 0.5 hour-5 hours.

4. The method for preparing tellurium nanowires according to claim 1, characterized in that: During the deoxidation treatment, the deoxidation temperature is 200° C.-1000° C., and the deoxidation time is 0.1 hour-2 hours.

5. The method for preparing tellurium nanowires according to claim 1, characterized in that: The growth temperature is 25°C to 200°C.

6. The method for preparing tellurium nanowires according to claim 5, characterized in that: The growth value is 1x10 -7 Torr-5x10 -6 Torr.

7. The method for preparing tellurium nanowires according to claim 6, characterized in that: In step S4, the growth time of the tellurium nanowires grown on the substrate is 0.1 minutes to 1000 minutes, preferably 1 minute to 100 minutes.

8. The method for preparing tellurium nanowires according to claim 1, characterized in that: In step S5, the substrate is in a rotating state, and the rotation speed is 1 rpm to 60 rpm, preferably 6 rpm to 20 rpm.

9. A tellurium nanowire, characterized in that: The tellurium nanowire is prepared by the method for preparing the tellurium nanowire according to any one of claims 1 to 8.

10. The tellurium nanowire according to claim 9, characterized in that: The average length of the tellurium nanowires is 100nm-10000nm; And / or, the density of the tellurium nanowires is 1x10 8 / cm -2 -1x10 10 / cm -2 .

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