CN112323143A

CN112323143A - Method for preparing two-dimensional bismuth oxide nanosheet through chemical vapor deposition

Info

Publication number: CN112323143A
Application number: CN202011095266.0A
Authority: CN
Inventors: 陈翔; 熊云海; 曾海波; 邹友生; 宋秀峰; 许多
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2021-02-05
Anticipated expiration: 2040-10-14
Also published as: CN112323143B

Abstract

The application provides a method for preparing two-dimensional bismuth oxide nanosheets by chemical vapor deposition, which comprises the following steps: uniformly mixing bismuth oxide powder and sodium chloride particles to obtain a first mixture; placing the first mixture in a first temperature zone of a dual-temperature-zone CVD tube furnace; placing the substrate in a second temperature zone of the dual-temperature-zone CVD tube furnace; filling a first inert gas with preset purity and pressure of 175-185 Pa into the double-temperature-zone CVD tube furnace; and heating the first temperature zone, heating the second temperature zone, and introducing argon and oxygen into the dual-temperature-zone CVD tube furnace for annealing at a flow ratio of 110-130: 30-60. The method for preparing the two-dimensional bismuth oxide nanosheets by chemical vapor deposition can be used for preparing the hexagonal bismuth oxide nanosheets with good chemical stability, and the method is carried out under the pressure of 175-185 Pa, so that the preparation method is safe and simple.

Description

Method for preparing two-dimensional bismuth oxide nanosheet through chemical vapor deposition

Technical Field

The application relates to the field of nanosheet preparation, in particular to a method for preparing a two-dimensional bismuth oxide nanosheet through chemical vapor deposition.

Background

The two-dimensional semiconductor nanosheet material has wide application prospects and development and application of potential new physical characteristics in the aspects of modern novel materials science, advanced energy, solar cells, photoelectric devices and the like due to unique ultrathin atomic-scale thickness, high carrier mobility, high on-off ratio, mechanical flexibility and obvious photoelectronics physical properties. In particular, the two-dimensional nanosheet material which is stable, good in crystallinity and appropriate in semiconductor band gap has unique advantages in Field Effect Transistors (FETs) and photodetectors, such as wide development and application of Transition Metal Disulfide (TMDCs) semiconductor nanosheet materials in optoelectronic devices. In recent years, a plurality of academic theoretical papers and experiments report the shapes of zero-dimensional spherical nanoparticles, one-dimensional nanowires, one-dimensional nanorods, one-dimensional nano hooks, three-dimensional nanoflowers and the like of Bismuth oxide (Bismuth oxide), and research the application of the Bismuth oxide in a plurality of fields such as photocatalysis, solar cells and the like. However, due to the bottleneck problem that the bismuth oxide semiconductor material is preferentially oriented along a one-dimensional direction in the growth process, it is difficult to experimentally prepare the two-dimensional nanosheet with the atomic-scale thickness. Thus, the one-dimensional bismuth oxide also limits the further development and application of the bismuth oxide in optoelectronic devices. Therefore, the two-dimensional bismuth oxide nanosheets with single or few layers can be prepared experimentally to research the specific characteristics of optoelectronic devices, which is a field problem to be solved urgently.

Disclosure of Invention

The application aims to provide a method for preparing two-dimensional bismuth oxide nanosheets by chemical vapor deposition, which can obtain two-dimensional bismuth oxide nanosheets with two-dimensional dimensions.

The embodiment of the application is realized as follows:

a method for preparing two-dimensional bismuth oxide nanosheets by chemical vapor deposition is characterized by comprising the following steps: uniformly mixing bismuth oxide powder and sodium chloride particles to obtain a first mixture; placing the first mixture in a first temperature zone of a dual-temperature-zone CVD tube furnace; placing the substrate in a second temperature zone of the dual-temperature-zone CVD tube furnace; filling the double-temperature-zone CVD tubular furnace with a first inert gas with preset purity; heating the first temperature zone at a speed of uniformly heating from room temperature to 790-810 ℃ within 38-42 min, then continuously and uniformly heating to 835-850 ℃ within 2-4 min, and keeping the temperature at 835-850 ℃ within 15-25 min; heating the second temperature zone at a speed of uniformly heating from room temperature to 290-310 ℃ within 13-17 min, then continuously and uniformly heating to 505-515 ℃ within 21-25 min, and keeping the temperature at 505-515 ℃ within a preset growth time; and introducing argon and oxygen into the dual-temperature-zone CVD tube furnace for annealing at a flow ratio of 110-130: 30-60.

Further, the mass ratio of the bismuth oxide powder to the sodium chloride particles in the first mixture is 110-120: 1.

Further, still include: and placing the clean silicon wafer in a UV light cleaning machine for ultraviolet heating and cleaning for 5-10 min to obtain the substrate.

Further, the thickness of the silicon wafer is 280-320 nm; and/or the length of the silicon wafer is 0.8-1.2 cm; and/or the width of the silicon wafer is 0.8-1.2 cm.

Further, still include: and cleaning the silicon wafer to obtain a clean silicon wafer.

Further, the step of cleaning the silicon wafer comprises: placing the silicon wafer in an acetone solution for ultrasonic cleaning for 8-12 min; then placing the silicon wafer in an absolute ethyl alcohol solution for ultrasonic cleaning for 8-12 min; then placing the silicon wafer in deionized water for ultrasonic cleaning for 8-12 min; and drying the silicon wafer by using a second inert gas.

Further, the second inert gas is nitrogen.

Further, the filling of the first inert gas with the preset purity in the dual-temperature-zone CVD tube furnace comprises: and evacuating the gas in the dual-temperature-zone CVD tubular furnace, filling the first inert gas into the dual-temperature-zone CVD tubular furnace, and repeating for many times until the purity of the first inert gas of the dual-temperature-zone CVD tubular furnace reaches the preset purity.

Further, the first inert gas is argon.

Further, still include: and after annealing, opening the dual-temperature-zone CVD tube furnace, and cooling the temperature in the dual-temperature-zone CVD tube furnace to room temperature.

The beneficial effects of the embodiment of the application are that: the method for preparing the two-dimensional bismuth oxide nanosheets by chemical vapor deposition can be used for preparing the hexagonal bismuth oxide nanosheets with good chemical stability, and the method is carried out under the pressure of 175-185 Pa, so that the preparation method is safe and simple.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a graph of the position of a first batch and a substrate within a dual temperature zone CVD tube furnace;

fig. 2 is an SEM image of individual bismuth oxide nanoplates of example 1;

fig. 3 is a TEM image of bismuth oxide nanoplates of example 1;

fig. 4 is an HRTEM atomic arrangement of bismuth oxide nanoplates of example 1;

fig. 5 is a nucleation density OM plot of bismuth oxide nanoplates prepared in example 1;

fig. 6 is a graph of the edge dimension length OM of bismuth oxide nanoplates prepared in example 1;

fig. 7 is an AFM image of the thickness dimension of bismuth oxide nanoplates prepared in example 1;

FIG. 8 is a Raman spectrum of the bismuth oxide nanosheets prepared in example 1 and the peak position variation at the corresponding thickness;

fig. 9 is an XPS plot and corresponding valences of bismuth oxide nanoplates prepared in example 1;

fig. 10 is an EDS plot and corresponding element distribution for bismuth oxide nanoplates prepared in example 1;

fig. 11 is an OM diagram of hexagonal bismuth oxide nanoplates prepared in example 2;

fig. 12 is an OM diagram of hexagonal bismuth oxide nanoplates prepared in example 3;

fig. 13 is an OM diagram of hexagonal bismuth oxide nanoplates prepared in example 4;

fig. 14 is an OM view of hexagonal bismuth oxide nanoplates prepared in example 5;

fig. 15 is an OM view of hexagonal bismuth oxide nanoplates prepared in example 6;

fig. 16 is an OM diagram of hexagonal bismuth oxide nanoplates prepared in comparative example 1;

fig. 17 is an OM diagram of hexagonal bismuth oxide nanoplates prepared in comparative example 2.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the embodiments of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. Specific meanings of the above terms in the embodiments of the present application can be understood in specific cases by those of ordinary skill in the art.

The invention provides a preparation method of a two-dimensional bismuth oxide nanosheet, wherein the chemical formula of the bismuth oxide nanosheet is bismuth oxide.

Example 1

Step (1): cutting a silicon wafer having a thickness of 300nmSiO2 into a size of 1cm × 1cm with a silicon knife;

step (2): respectively placing the cut silicon wafer with the size of 1cm multiplied by 1cm in acetone (C3H6O) with the industrial grade purity of more than 99.95%, absolute ethyl alcohol (C2H6O) with the purity of more than 99.97% and deionized water (H2O), ultrasonically cleaning for 10min by using an ultrasonic machine with the power of 200W, and drying by using N2;

and (3): placing the cleaned clean silicon wafer in a 300W power UV light cleaning machine for ultraviolet heating cleaning for 5-10 min, and taking the cleaned clean silicon wafer as a substrate for later use;

and (4): weighing 115mg of pure bismuth oxide powder and 1mg of NaCl salt particles in a glove box, stirring and mixing to obtain a first mixture, placing the first mixture at the front end of a first temperature zone of a dual-temperature-zone CVD tube furnace (shown in figure 1), and placing a 1cm multiplied by 1cm silicon wafer which is cleaned by UV light at the tail end of a second temperature zone of the dual-temperature-zone CVD tube furnace to be used as a deposition substrate (shown in figure 1);

and (5): filling argon into the double-temperature-zone CVD tubular furnace, vacuumizing by using a mechanical pump, repeating for 3 times, and removing gas remained in the double-temperature-zone CVD tubular furnace to ensure that the purity of the argon in the double-temperature-zone CVD tubular furnace reaches a preset purity, wherein the preset purity can be 99.5%;

and (6): setting a heating temperature rise curve, wherein the temperature of the first temperature zone is raised to 800 ℃ within 40min, then raised to 850 ℃ within 3min, and the temperature is kept at 850 ℃ for 20 min; the temperature of the second temperature zone is increased to 300 ℃ in 15min, then is increased to 510 ℃ in 23min, and the growth time is preset for 5 min;

and (7): starting a CVD heating mode, and adjusting the flow ratio of Ar to O2 to be 100: 60 (unit: sccm), the flow ratio is maintained until the annealing is finished;

and (8): and after the annealing is finished, opening the CVD tube furnace, rapidly cooling, stopping the growth process, and finally performing characterization observation to obtain the bismuth oxide nanosheets with the hexagonal morphology.

FIG. 2 is an SEM image of a single bismuth oxide nanosheet of example 1, showing that the morphology of the prepared bismuth oxide nanosheet is regular hexagonal; FIG. 3 is a TEM image of the bismuth oxide nanosheet of example 1, and the prepared bismuth oxide can be judged to be a single crystal material by the TEM diffraction pattern; fig. 4 is an HRTEM atomic arrangement diagram of a bismuth oxide nanosheet of example 1, according to the high-resolution atomic arrangement diagram, the distance measured by the interplanar spacing is 0.45nm, and the obtained bismuth oxide material is an α -phase single-crystal bismuth oxide material according to PDF card of the bismuth oxide material by XRD; fig. 5 is a nucleation density OM plot of bismuth oxide nanoplates prepared in example 1; fig. 6 is a graph of the edge dimension length OM of bismuth oxide nanoplates prepared in example 1; FIG. 7 is an AFM plot of the thickness dimension of the bismuth oxide nanoplates prepared in example 1, the thickness reaching the atomic scale, about 1.32 nm; FIG. 8 is a Raman spectrum of the bismuth oxide nanosheets prepared in example 1 and the peak position variation at the corresponding thickness; fig. 9 is an XPS diagram and corresponding valence of the bismuth oxide nanosheet prepared in example 1, and a bismuth oxide material having sample components consisting of Bi and O elements can be obtained according to the valence energy state of Bi 4f orbital of bismuth oxide and the valence energy state of 1s orbital of O element; fig. 10 is an EDS diagram of the bismuth oxide nanosheet prepared in example 1 and the distribution of the corresponding elements, and it can be seen that the Bi and O elements are uniformly distributed on the nanosheet according to the area scan distribution of the EDS.

Example 2

Similar to example 1, except that the preset growth time in step (6) of example 1 was adjusted to 10 min.

The OM edge dimension length of the hexagonal bismuth oxide nanosheets prepared in this example 2 is shown in fig. 11, from which it can be seen that the edge dimension length of the nanosheets is 13 μm. The obtained hexagonal bismuth oxide nano-sheet is regular.

Example 3

Similar to example 1, except that the preset growth time in step (6) of example 1 was controlled to 15 min.

The OM edge dimension length of the hexagonal bismuth oxide nanosheet prepared in this example is shown in fig. 12, and it can be seen from the figure that the edge dimension length of the nanosheet is 18 μm.

Example 4

Similar to example 1, except that the preset growth time in step (6) of example 1 was controlled to be 20 min.

The OM edge dimension length of the hexagonal bismuth oxide nanosheet prepared in this example is shown in fig. 13, and it can be seen from the figure that the edge dimension length of the nanosheet is 20 μm.

Example 5

Similar to example 1, except that the preset growth time in step (6) of example 1 was adjusted to 25 min.

The OM edge dimension length of the hexagonal bismuth oxide nanosheets prepared in this example is shown in fig. 14, from which it can be seen that the edge dimension length of the nanosheets is 25 μm.

The Raman images of the thicknesses of the bismuth oxide nanosheets corresponding to different growth times in examples 2-5 are shown in FIG. 7, and it can be seen that the Raman peak appears in a blue shift phenomenon obviously along with the thinning of the thickness at the position of a characteristic peak 95 cm-1. The method shows that the selection of the heat preservation growth time of the CVD tube furnace plays a crucial role in the size and thickness of the nanosheets, the size and thickness of the transverse edge of the hexagonal bismuth oxide nanosheets are increased along with the increase of the growth time, the nanosheets are complete in crystal form, and the morphology is regular.

Example 6

Similar to example 1, except that the gas flow ratio Ar: O2 in step (7) of example 1 was adjusted to 130:30 (unit: sccm).

The OM nucleation density graph of the nanosheets prepared in this example is shown in fig. 15, and it can be seen from the graph that the nucleation density of the obtained hexagonal bismuth oxide nanosheets is increased, which indicates that the bismuth oxide nucleation density can be improved by adjusting the flow rate of O2 at a total flow rate of 160 sccm.

Comparative example 1

Similar to example 1, except that the mass of the NaCl salt particles in step (4) of example 1 was adjusted to 10 mg.

The OM diagram of the nanosheets prepared in this example is shown in fig. 16, and it can be seen from the diagram that the grown bismuth oxide nanosheets are irregular hexagonal nanosheets, have helical flower-like shapes at the central positions, and have uneven thicknesses.

Comparative example 2

Similar to example 1, except that Ar: O2 in step (7) of example 1 was adjusted to 30:30 (unit: sccm).

The OM diagram of the bismuth oxide nanosheet prepared in this example is shown in fig. 17, and it is seen from the diagram that since the total flow rate of gas is too small, the number of bismuth oxide growth nuclei is small, and the shape is irregular.

The experimental structure shows that the preparation method provided by the invention is simple to operate and is carried out under the condition of low pressure of 180 Pa. In the method, variable pressure intensity (P/Pa), airflow (Sccm) and precursor and substrate temperature (T/DEG C) are controlled, and hexagonal bismuth oxide nanosheets with different two-dimensional edge lengths of 3-50 mu M and thicknesses of 1-40 nm can be obtained by controlling the mass (M/mg) and reaction time (T/min) of specific precursor powder; the bismuth oxide nanosheet prepared through verification of a Transmission Electron Microscope (TEM) diffraction pattern and a high-resolution transmission microscope (HRTEM) atomic arrangement has good single crystal property; the picture of an Optical Microscope (OM) shows that the prepared bismuth oxide nanosheet has high nucleation density and different edge sizes; bismuth oxide nano-sheets with different thicknesses are obtained through an Atomic Force Microscope (AFM) test; through Raman spectrometer (Raman) analysis and test, a blue shift phenomenon appears at a characteristic peak of the bismuth oxide, the thinning change of the prepared bismuth oxide nano-sheet on the thickness is also proved, meanwhile, the Raman peak basically has no change within one month, and the stability of the crystal structure of the bismuth oxide nano-sheet is proved; the pure valence bond of Bi-O combination is obtained by X-ray photoelectron spectroscopy (XPS) valence bond analysis; meanwhile, the surface of the hexagonal nanosheet is also scanned by an Energy Dispersive Spectrometer (EDS) element distribution surface, and the fact that the obtained hexagonal nanosheet is Bi and O elements of the bismuth oxide component is also proved.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing two-dimensional bismuth oxide nanosheets by chemical vapor deposition is characterized by comprising the following steps:

uniformly mixing bismuth oxide powder and sodium chloride particles to obtain a first mixture;

placing the first mixture in a first temperature zone of a dual-temperature-zone CVD tube furnace;

placing the substrate in a second temperature zone of the dual-temperature-zone CVD tube furnace;

filling a first inert gas with preset purity and pressure of 175-185 Pa into the double-temperature-zone CVD tube furnace;

heating the first temperature zone at a speed of uniformly heating from room temperature to 790-810 ℃ within 38-42 min, then continuously and uniformly heating to 835-850 ℃ within 2-4 min, and keeping the temperature at 835-850 ℃ within 15-25 min;

heating the second temperature zone at a speed of uniformly heating from room temperature to 290-310 ℃ within 13-17 min, then continuously and uniformly heating to 505-515 ℃ within 21-25 min, and keeping the temperature at 505-515 ℃ within a preset growth time;

and introducing argon and oxygen into the dual-temperature-zone CVD tube furnace for annealing at a flow ratio of 110-130: 30-60.

2. The method for preparing two-dimensional bismuth oxide nanosheets by chemical vapor deposition according to claim 1, wherein the mass ratio of the bismuth oxide powder to the sodium chloride particles in the first mixed material is 110-120: 1.

3. The method of chemical vapor deposition fabrication of two-dimensional bismuth oxide nanoplates of claim 1, further comprising: and placing the clean silicon wafer in a UV light cleaning machine for ultraviolet heating and cleaning for 5-10 min to obtain the substrate.

4. The chemical vapor deposition method for producing two-dimensional bismuth oxide nanoplates as recited in claim 3,

the thickness of the silicon wafer is 280-320 nm; and/or the presence of a gas in the gas,

the length of the silicon wafer is 0.8-1.2 cm; and/or the presence of a gas in the gas,

the width of the silicon wafer is 0.8-1.2 cm.

5. The method of chemical vapor deposition fabrication of two-dimensional bismuth oxide nanoplates of claim 1, further comprising: and cleaning the silicon wafer to obtain a clean silicon wafer.

6. The method for preparing two-dimensional bismuth oxide nanosheets by chemical vapor deposition as recited in claim 5, wherein the step of cleaning the silicon wafer comprises:

placing the silicon wafer in an acetone solution for ultrasonic cleaning for 8-12 min;

then placing the silicon wafer in an absolute ethyl alcohol solution for ultrasonic cleaning for 8-12 min;

then placing the silicon wafer in deionized water for ultrasonic cleaning for 8-12 min;

and drying the silicon wafer by using a second inert gas.

7. The method for preparing two-dimensional bismuth oxide nanoplates by chemical vapor deposition of claim 6, wherein the second inert gas is nitrogen.

8. The method for preparing two-dimensional bismuth oxide nanosheets by chemical vapor deposition as defined in claim 1, wherein the saturating of the dual-temperature zone CVD tube furnace with a predetermined purity of a first inert gas comprises:

and evacuating the gas in the dual-temperature-zone CVD tubular furnace, filling the first inert gas into the dual-temperature-zone CVD tubular furnace, and repeating for many times until the purity of the first inert gas of the dual-temperature-zone CVD tubular furnace reaches the preset purity.

9. The method for preparing two-dimensional bismuth oxide nanoplates by chemical vapor deposition of claim 1 or 8, wherein the first inert gas is argon.

10. The method of chemical vapor deposition fabrication of two-dimensional bismuth oxide nanoplates of claim 1, further comprising: and after annealing, opening the dual-temperature-zone CVD tube furnace, and cooling the temperature in the dual-temperature-zone CVD tube furnace to room temperature.