A method for preparing ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheets

Abstract

The application discloses a preparation method of ternary Sb2(Se 1‑x Te x )3 two-dimensional nanosheets and belongs to the technical field of semiconductor nanomaterial preparation. The application utilizes a chemical vapor deposition method, takes antimony telluride powder and elemental selenium powder as an evaporation source, takes argon as a deposition reaction atmosphere, and obtains high-quality Sb2(Se 1‑x Te x )3 two-dimensional nanosheets with adjustable composition by adjusting the proportion, position and reaction temperature of a growth source. The method has simple process and low requirement on equipment, and the prepared Sb2(Se 1‑x Te x )3 two-dimensional nanosheets have adjustable composition and have high research value and application prospect in the field of nano-optoelectronic devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor nanomaterial preparation, and more particularly discloses a preparation method of ternary Sb2(Se 1- x Te x )3 two-dimensional nanosheets. BACKGROUND

[0002] Sb2Te3 and Sb2Se3 are both narrow-bandgap semiconductors, and their bandgaps are 0.23 eV and 1.17 eV, respectively, and have good photoelectric and thermoelectric properties, and can be used for preparing infrared detectors and thermoelectric devices. The elements related to the two are rich in earth reserves and have little environmental pollution, and are inorganic P-type semiconductor materials with broad application prospects. On the other hand, as a VA-VIA semiconductor, the selenium atom and the tellurium atom can be replaced with each other due to their similar radii, so it is expected to prepare a ternary antimony selenium tellurium compound. On this basis, by adjusting the material composition and controlling the selenium tellurium ratio, we can obtain a ternary antimony selenium tellurium compound with a continuously adjustable bandgap (between 0.23 eV and 1.17 eV), which will be conducive to further exploring the VA-VIA semiconductor system and enriching the related research content.

[0003] At present, the main existing form of the prepared ternary antimony selenium tellurium compound is a bulk alloy and a thin film, and there is no report on the preparation of ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheets by a chemical vapor deposition method. Compared with the bulk alloy and the thin film, the prepared two-dimensional ternary antimony selenium tellurium single-crystal nanosheet has high crystal quality, fewer grain boundaries, a continuously adjustable bandgap, and good electrical transport properties, which is of great significance for the research of new photoelectric detectors. SUMMARY

[0004] In view of the blank of the prior art, the application provides a preparation method of ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheets, which has simple process, low requirement for equipment and controllable composition.

[0005] In order to achieve the above purpose, the application adopts the following technical scheme:

[0006] The preparation method of the ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheet comprises the following steps:

[0007] (1) a quartz boat containing elemental selenium powder is placed upstream of a heating center as a first evaporation source, another quartz boat containing antimony telluride powder is placed at the heating center of a horizontal tube furnace as a second evaporation source, and a substrate is placed downstream of the heating center of the tube furnace;

[0008] (2) hydrogen gas as a catalyst and argon gas as a material are introduced into the quartz tube for reaction, the flow rate is adjusted, the heating temperature and time are set, the tube furnace is started, and the chemical vapor deposition reaction is carried out in the quartz tube, and after the program of the tube furnace is completed, the substrate is taken out, and the surface of the substrate is the grown ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheet.

[0009] Further, the preparation method of the ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheet in step (1) is characterized in that the first evaporation source is located upstream of the quartz tube, and the distance from the heating center is 285-300 mm, the substrate is located downstream of the quartz tube, and the distance from the heating center is about 190 mm; and the mass ratio of the elemental selenium powder to the antimony telluride is 1:5-1:2.

[0010] Further, the substrate in step (1) is a natural mica sheet, the natural mica sheet is cut into a square with a size of 1.5 cm*1.5 cm, and the natural mica sheet is naturally separated into two thin sheets between layers, and a new separation surface is selected as a growth surface.

[0011] Further, in step (2), the volume ratio of the mixture of hydrogen gas and argon gas is 1:19, and the flow rate of the mixed gas is 90-100 sccm.

[0012] Further, the temperature of the heating center in step (2) is set to 510-530 DEG C, and the reaction time is set to 25 min.

[0013] The sample obtained by the method is a ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheet, wherein x is the mole fraction of Te in the non-metallic element, 1-x is the mole fraction of Te in the non-metallic element, and 0

[0014] The method has the advantages of simple process, low requirement for equipment, high crystal quality of the prepared Sb2(Se 1-x Te x )3 two-dimensional nanosheet, fewer grain boundaries, continuous band gap, and good electrical transport properties, which is of great significance for the research of new photoelectric detectors. The ternary nanosheet of antimony selenium tellurium is prepared by CVD for the first time, which enriches the ternary two-dimensional material system and has important significance for the research of nanoscale optoelectronic devices. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 (a) and (b) show optical images of the ternary Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application.

[0016] Figure 2 (a) and (b) show optical images of the ternary Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application.

[0017] Figure 3 (a) and (b) are atomic force (AFM) microscope images and height information of the ternary Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application.

[0018] Figure 4 (a) and (b) are atomic force (AFM) microscope images and height information of the ternary Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application.

[0019] Figure 5 (a) and (b) are atomic force (AFM) microscope images and height information of the ternary Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application. 1-x Te x )3 two-dimensional monocrystalline nanosheets of component 1 transferred onto copper mesh (a), corresponding selected area electron diffraction (SAED) image (b), corresponding high-resolution TEM (HRTEM) image (c), and EDS map (d) thereof. (e) and (f) are images of Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets of component 2 transferred onto copper mesh, corresponding selected area electron diffraction (SAED) image (f), corresponding high-resolution TEM (HRTEM) image (g), and EDS map (h) thereof. DETAILED DESCRIPTION

[0020] In order to further understand the content of the present application, the present application is further described below in conjunction with examples.

[0021] Example 1

[0022] (1) Preparation of natural mica sheet substrate

[0023] 1) The natural mica sheet was cut into a square sheet of 1.5 cm * 1.5 cm using a craft knife.

[0024] 2) Use a sharp pair of tweezers to separate the natural mica sheet into two pieces from the middle of the layer, and use the newly separated clean side as the growth substrate.

[0025] (2) Put 10 mg of selenium powder in a quartz boat and place it 295 mm upstream from the heating center, and then put about 50 mg of antimony telluride powder in another quartz boat and place it at the center of the heating source of the horizontal tube furnace. Place the natural mica substrate 22-23.5 cm downstream from the heating center of the tube furnace.

[0026] (3) Vacuumize the quartz tube in the furnace, and when the vacuum reaches 0.8 Pa, introduce hydrogen gas as a catalyst and argon gas as an atmosphere for material reaction and growth into the quartz tube for reaction. The volume ratio of hydrogen gas to argon gas is controlled to be 1:19, and the flow rate of the mixed gas is adjusted to be 100 sccm.

[0027] (4) Set the heating temperature to 530°C, keep the heating rate at 10°C / min, and set the reaction time to 25 min. Then turn on the tube furnace and run the program to perform vapor deposition reaction in the quartz tube. After the program of the tube furnace is completed, take out the substrate, and the surface of the substrate is the grown ternary Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheet. Record such a nanosheet as compound 1, wherein the atomic ratio of the three elements Sb, Se, and Te is about 2:1:2.

[0028] Example 2

[0029] (1) Preparation of natural mica sheet substrate

[0030] 1) Use an art knife to cut the natural mica sheet into a square sheet of 1.5 cm*1.5 cm.

[0031] 2) Use a sharp pair of tweezers to separate the natural mica sheet into two pieces from the middle of the layer, and use the newly separated clean side as the growth substrate. (2) Put 15 mg of selenium powder in a quartz boat and place it 285 mm upstream from the heating center, and then put about 30 mg of antimony telluride powder in another quartz boat and place it at the center of the heating source of the horizontal tube furnace. Place the natural mica substrate 19-20.5 cm downstream from the heating center of the tube furnace.

[0032] (3) Vacuumize the quartz tube in the furnace, and when the vacuum reaches 0.8 Pa, introduce hydrogen gas as a catalyst and argon gas as an atmosphere for material reaction and growth into the quartz tube for reaction. The volume ratio of hydrogen gas to argon gas is controlled to be 1:19, and the flow rate of the mixed gas is adjusted to be 100 sccm.

[0033] (4) Set the heating temperature to 510 °C, keep the heating rate at 10 °C / min, and set the reaction time to 25 min. Then, open the tube furnace and run the program to make the quartz tube perform the vapor deposition reaction. After the program of the tube furnace ends, take out the substrate, and the surface of the substrate is the grown ternary Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheet. The nanosheet thus composed is denoted as compound 2, wherein the atomic ratio of the three elements Sb, Se and Te is about 2:2:1.

[0034] Figure 1 (a) and (b) show optical images of the Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application. The OM images show that the lateral size of the nanosheets can reach at least 10 um, which is convenient for subsequent preparation of related optoelectronic devices.

[0035] Figure 2 show the X-ray diffraction (XRD) data patterns of the Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application.

[0036] Figure 3 (a) and (b) show atomic force (AFM) microscope images and height information of the Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application. Different compositions of the Sb2(Se 1-x Te x )3 two-dimensional nanosheets can have an ultrathin longitudinal thickness <10 nm.

[0037] Figure 4 show the Raman spectra of the Sb2(Se 1-x Te x )3 two-dimensional monocrystalline nanosheets prepared in Examples 1-2 of the present application. In the figure, the A 1 1g , E 2 g , A 2 1g , A g characteristic peaks prove that the obtained nanosheets are Sb2(Se 1-x Te x )3 nanosheets.

[0038] Figure 5 show the two-dimensional Sb2(Se 1-x Te x)3 single-crystal nanosheets images (a) and (e), corresponding selected-area electron diffraction (SAED) patterns (b) and (f), high-resolution TEM (HRTEM) images (c) and (g), and energy dispersive spectroscopy (EDS) spectra (d) and (h). The selected-area electron diffraction (SAED) patterns exhibit diffraction spots, supporting the evidence that these thin sheets have high-quality single-crystal hexagonal structures, where the perfect hexagonal lattices have no obvious defects in the high-resolution TEM (HRTEM) images (c) and (g). The energy dispersive spectroscopy (EDS) spectra (d) and (h) indicate that the nanosheets contain antimony, selenium, and tellurium elements, where (d) indicates that the atomic ratio of the three elements of Sb, Se, and Te is 2:1:2, and (h) indicates that the atomic ratio of the three elements of Sb, Se, and Te is 2:2:1.

Claims

1. A method for preparing ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheets, characterized in that, The method comprises the following steps: (1) placing elemental selenium powder in a quartz boat upstream of the heating center as a first evaporation source, placing antimony telluride powder in another quartz boat at the heating center of the horizontal tube furnace as a second evaporation source, and placing a substrate downstream of the heating center of the tube furnace; the first evaporation source is located upstream of the quartz tube, and the distance from the heating center is 285-300 mm; the substrate is located downstream of the quartz tube, and the distance from the heating center is 190-235 mm; the mass ratio of the elemental selenium powder to the antimony telluride is 1:5-1:2; the temperature of the heating center is 510-530 ℃, and the reaction time is 25 min; (2) hydrogen and argon as the material reaction growth atmosphere into the quartz tube for reaction, and adjust the flow rate, set the heating temperature and time, open the tube furnace, so that the quartz tube for chemical vapor deposition reaction, after the tube furnace program ends after taking out the substrate, the substrate surface is the growth of ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheet; (2) hydrogen and argon as the material reaction growth atmosphere into the quartz tube for reaction, and adjust the flow rate, set the heating temperature and time, open the tube furnace, so that the quartz tube for chemical vapor deposition reaction, after the tube furnace program ends after taking out the substrate, the substrate surface is the growth of ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheet; wherein x is the mole fraction of Te in the non-metallic element, 1-x is the mole fraction of Te in the non-metallic element, and 0 2. A method of preparing ternary Sb2(Se 1-x Te x )3 two-dimensional nanoplatelets according to claim 1, characterized in that, The substrate in step (1) is a natural mica sheet, the natural mica sheet is cut into a square with a size of 1.5 cm*1.5 cm, and the natural mica sheet is naturally separated into two thin sheets between layers, and a new separation surface is selected as a growth surface.

3. A method of preparing ternary Sb2(Se 1-x Te x )3 two-dimensional nanosheets according to claim 1, characterized by, The volume ratio of the mixture of hydrogen and argon in step (2) is 1:19; the flow rate of the mixed gas is 90-100 sccm.

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