阅读说明：本技术 一种快速生长超薄大尺寸单晶过渡金属硫/硒化物的方法 (Method for rapidly growing ultrathin large-size single crystal transition metal sulfur/selenide ) 是由 沈俊 鄢江兵 湛立 王旭 张鑫 崔恒清 于 2020-12-22 设计创作，主要内容包括：本发明属于电子元器件领域,具体涉及一种快速生长超薄大尺寸单晶硫化钨的方法。该方法为：S1:一定量高纯硫于石英舟中放置于小石英管的上游；一定量高纯WO-3粉体于石英舟中放置于小石英管的下游；并将硅或二氧化硅衬底氧化层面向下放置于放置高纯WO-3粉体的石英舟表面；S2:调节氩气和氢气尽可能清除管内氧气；S3:开始加热,氩气保持40±0.05sccm；达到预设温度后,调节氩气和氢气流量,气压保持为常压；然后生长5±0.5min得单晶硫化钨。该方法简单,而且能制备出大尺寸单晶组成的连续薄膜。(The invention belongs to the field of electronic components, and particularly relates to a method for rapidly growing ultrathin large-size monocrystal tungsten sulfide. The method comprises the following steps: s1, placing a certain amount of high-purity sulfur in the quartz boat and on the upstream of the small quartz tube; a certain amount of high purity WO 3 Placing the powder in a quartz boat at the downstream of a small quartz tube; and placing the silicon or silicon dioxide substrate oxide layer face down on the high-purity WO 3 The surface of a quartz boat of powder; s2, adjusting argon and hydrogen to remove oxygen in the tube as much as possible; s3, starting heating, and keeping argon gas at 40 plus or minus 0.05 sccm; after the preset temperature is reached, the flow rates of argon and hydrogen are adjusted, and the air pressure is kept at normal pressure; then growing for 5 plus or minus 0.5min to obtain the single crystal tungsten sulfide. The method is simple and can prepare continuous films consisting of large-size single crystals.)

1. The method for rapidly growing the ultrathin large-size monocrystal transition metal sulfur/selenide is characterized by comprising the following steps of:

s1, placing a certain amount of high-purity sulfur/selenium in the container a and upstream of the tubular part a; placing a certain amount of high-purity transition metal oxide powder in a container b and placing the container b at the downstream of the tubular component; placing the silicon substrate containing the oxidation layer on the surface of the container b for placing the high-purity transition metal oxide powder with the oxidation layer facing downwards; and placing the tubular member a into the tubular member b; both ends of the tubular part a and the tubular part b are open;

s2, pumping the pressure of the tubular furnace to 4 +/-0.05 Pa, continuously introducing argon gas of 400 +/-0.05 sccm until the pressure of the tubular furnace returns to normal pressure, opening the gas outlet valve, and simultaneously adjusting the flow of the argon gas to 40 +/-0.05 sccm and the flow of the hydrogen gas to 0 sccm;

s3, starting heating, adjusting the argon flow to 200 plus or minus 0.05sccm and the hydrogen flow to 5 plus or minus 0.05sccm after reaching the preset temperature, and keeping the air pressure at normal pressure; growing for 5 +/-0.5 min under the condition, and then cooling to obtain the ultrathin large-size monocrystal transition metal sulfur/selenide; the preset temperature specifically comprises the following steps: the area for placing the high-purity sulfur/selenium is heated to 200 +/-5 ℃, and meanwhile, the area for placing the transition metal oxide powder is heated to the sublimation temperature of the corresponding transition metal oxide under normal pressure;

argon and/or hydrogen gas is introduced from the upstream end and is discharged from the downstream end.

2. The method of claim 1, wherein the containers a and b are quartz containers and/or corundum containers; the tubular parts a and b are quartz tubes and/or corundum tubes with different diameters.

3. The method of claim 1, wherein in S1, the distance between container a and container b is 20-30 cm.

4. The method of claim 1, the single crystalline transition metal sulfide/selenide being WS₂Or MoS₂Or MoSe₂Or WSe₂。

5. The method of claim 4, wherein the single crystal transition metal sulfide/selenide is WS₂(ii) a The transition metal oxide is WO₃(ii) a In S3, the temperature rise in the region where the high-purity sulfur is placed is specifically: firstly, heating up from 0 ℃ to 10 ℃ at a heating rate of 0.5 ℃/min, and then heating up to 200 +/-5 ℃ at a heating rate of 19 +/-0.5 ℃/min; placing WO₃The temperature rise in the powder region is specifically: the sublimation temperature is 850 +/-5 ℃, and the temperature is increased from 0 ℃ to 850 +/-5 ℃ at the heating rate of 28 +/-0.5 ℃/min.

6. The method according to any one of claims 1 to 5, wherein the temperature is rapidly decreased immediately after the growth in S3 is completed.

7. The method of claim 6, wherein the temperature is rapidly decreased and the hydrogen gas is adjusted to 0 ± 0.05 seem and the argon gas is adjusted to 400 ± 0.05 seem.

8. An ultra-thin large-sized single-crystal transition metal sulfide/selenide prepared by the method of any one of claims 1 to 7.

9. The ultra-thin large-sized single crystal transition metal sulfur/selenide according to claim 8, wherein the ultra-thin large-sized single crystal transition metal sulfur/selenide is ultra-thin large-sized single crystal tungsten sulfide, has a thickness of 0.8 ± 0.05nm, and has a size of 18-300 um.

10. Use of the ultra-thin large size single crystalline transition metal sulfur/selenide of claim 8 or the ultra-thin large size single crystalline tungsten sulfide of claim 9 in photodetectors and/or biosensors and/or photocatalysts and/or electrochemical energy storage and conversion and/or integrated circuits and/or biosensors.

Technical Field

The invention belongs to the field of electronic components, and particularly relates to a method for rapidly growing ultrathin large-size single crystal transition metal sulfur/selenide.

Background

Since the discovery of graphene by Novoselov et al in 2004, two-dimensional layered materials have attracted extensive attention by researchers in the world due to their unique structural, mechanical and physical properties and potential applications. Transition metal chalcogenides (TMDs) have a two-dimensional layered structure similar to graphene, with layer-to-layer interactions through van der waals forces. WS₂It has attracted extensive research interest due to its diverse functions, including tunable band gap of 1.3-2.05eV, strong optical-substance interaction and spin-valley coupling phenomena. More importantly, WS₂Has high phonon limit mobility due to its low electron effective mass.

Today, mechanical lift-off is a simple way to achieve high quality single and multilayer TMDs, but the uncontrollable thickness, relatively small lateral dimensions and poor yield prevent further application and commercialization. CVD (chemical vapor deposition) has been widely used in the production of atomic thin TMDs as a cost-effective and scalable process. However, in the process of preparing these materials by CVD, the regulation of the shape and the number of layers of the thin film is still difficult, and the large-size growth in a large range still has challenges, which prevent the large-scale application of the materials in the future. Industrial application requires a continuous thin film of a wafer size, however, to date, successfully prepared continuous thin films are generally formed by connecting small-sized single crystal thin films, a large number of grain boundaries exist in the thin films, which will certainly degrade the performance of devices, and continuous thin films composed of large-sized single crystals are more suitable for practical use. Therefore, the growth of the large-size single crystal thin film by a simple method has very important practical significance.

At present, the common process for preparing TMDs by CVD is complicated, the whole process consumes too long time, the actual application requirements are difficult to meet, and the improvement of the preparation conditions is not easy. How to control the concentration of the precursor in the growth process, shorten the reaction time and have important significance for preparing the transition metal sulfide of high-quality large-area single crystal.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for preparing an ultra-thin large-sized single crystal transition metal sulfide/selenide, which has the advantages of simple process, mild preparation conditions, and capability of effectively controlling the shape and the number of layers of the prepared transition metal sulfide/selenide, so as to prepare a large-sized continuous transition metal sulfide/selenide single crystal film. The distance of the vessel carrying the raw material, the carrier gas type, the sample growth time, and the growth temperature all affect WS in the present invention₂The elements of growth.

In the technical solution, it should be noted that: the term "simultaneously" used in the present technical solution does not necessarily need to be absolutely consistent in physical time, but has a certain operation sequence and an interval range of operation time, and in a certain normal operation sequence and interval range of operation time, we want to be regarded as equivalent infringement.

The method comprises the following steps:

s1, placing a certain amount of high-purity sulfur/selenium in the container a and upstream of the tubular part a; placing a certain amount of high-purity transition metal oxide powder in a container b and placing the container b at the downstream of the tubular component; placing the silicon substrate containing the oxidation layer on the surface of the container b for placing the high-purity transition metal oxide powder with the oxidation layer facing downwards; and placing the tubular member a into the tubular member b; both ends of the tubular part a and the tubular part b are open;

s2, pumping the pressure of the tubular furnace to 4 +/-0.05 Pa, continuously introducing argon gas of 400 +/-0.05 sccm until the pressure of the tubular furnace returns to normal pressure, opening the gas outlet valve, and simultaneously adjusting the flow of the argon gas to 40 +/-0.05 sccm and the flow of the hydrogen gas to 0 sccm;

s3, starting heating, adjusting the argon flow to 200 plus or minus 0.05sccm and the hydrogen flow to 5 plus or minus 0.05sccm after reaching the preset temperature, and keeping the air pressure at normal pressure; growing for 5 +/-0.5 min under the condition, and then cooling to obtain the ultrathin large-size monocrystal transition metal sulfur/selenide; the preset temperature specifically comprises the following steps: the area for placing the high-purity sulfur/selenium is heated to 200 +/-5 ℃, and meanwhile, the area for placing the transition metal oxide powder is heated to the sublimation temperature of the corresponding transition metal oxide under normal pressure;

argon and/or hydrogen gas is introduced from the upstream end and is discharged from the downstream end.

Further, the container a, the container b, the tubular member a and the tubular member b are reasonably selected by those skilled in the art according to actual environment and operation, the container material of the technical scheme is unchanged at high temperature, the temperature resistance is not specifically stated in the claims, and not all materials can be represented, which can be freely determined by those skilled in the art. Preferably, the container a and the container b are quartz containers or rigid containers; more preferably a quartz container, and the preparation process of the quartz material is mature and has lower price. In particular, the container may be boat-shaped or other shape that can carry material.

Further, the thickness of the oxide layer is different when observed under a microscope, and WS on a silicon wafer with the oxide layer of 300nm is preferred₂The observation is clearer than at 2000 nm.

Further, the tubular parts a and b are quartz tubes and/or corundum tubes with different diameters.

Preferably, in S1, the distance between the container a and the container b is 20-30 cm.

Further, the transition metal is a metal in groups IV, V, VI, VII, IX and X of the periodic Table of the elements, and is preferably tungsten (W) or molybdenum (Mo).

More preferably, the single crystal transition metal sulfide/selenide is WS₂Or MoS₂Or MoSe₂Or WSe₂。

More preferably, the single crystal transition metal sulfide/selenide is WS₂(ii) a The transition metal oxide is WO₃(ii) a In S3, the temperature rise in the region where the high-purity sulfur is placed is specifically: firstly, heating up from 0 ℃ to 10 ℃ at a heating rate of 0.5 ℃/min, and then heating up to 200 +/-5 ℃ at a heating rate of 19 +/-0.5 ℃/min; placing WO₃The temperature rise in the powder region is specifically: the sublimation temperature is 850 +/-5 ℃, and the temperature is increased from 0 ℃ to 850 +/-5 ℃ at the heating rate of 28 +/-0.5 ℃/min.

Specifically, the temperature rise from 0 ℃ is helpful to improve the temperature rise stability of the system, and other technical schemes that reach the preset temperature at the preset time according to actual conditions are expected to be regarded as infringement.

Preferably, the temperature of the growth in S3 is rapidly reduced immediately after the growth is completed, regardless of the above-mentioned options for the container and the tubular member, and the transition metal.

Preferably, the rapid cooling means includes, but is not limited to, rapid opening of the furnace.

Specifically, the adjustment of the atmosphere after the end of production in S3, as in the adjustment of the atmosphere in S2 and S3, can effectively control the concentration of the precursor in the vicinity of the silicon wafer; the preparation time is also shortened by opening the hearth, which is beneficial to the WS with high quality₂And (5) forming a thin film.

More preferably, the temperature is rapidly decreased and simultaneously hydrogen gas is adjusted to 0 + -0.05 sccm and argon gas is adjusted to 400 + -0.05 sccm.

The invention aims to provide the ultrathin large-size monocrystal transition metal sulfide/selenide prepared by the method for preparing the ultrathin large-size monocrystal transition metal sulfide/selenide. The aforementioned preparation schemes mentioned in the technical scheme include a preferred technical scheme and a general technical scheme. The transition metal sulfur/selenide prepared by the method is a continuous film consisting of large-size single crystals, and is more suitable for practical application.

Further, the ultrathin large-size monocrystal transition metal sulfur/selenide is ultrathin large-size monocrystal tungsten sulfide, the thickness is 0.8 +/-0.05 nm, and the size is 18-300 mu m.

The invention also aims to provide application of the ultrathin large-size single crystal transition metal sulfur/selenide or the ultrathin large-size single crystal tungsten sulfide in a photoelectric detector and/or a biosensor and/or photocatalysis and/or electrochemical energy storage and conversion and/or an integrated circuit and/or a biosensor.

The invention has the beneficial effects that:

the method for preparing the single crystal transition metal sulfur/selenide provided by the invention can obtain the continuous film consisting of the needed large-size single crystal within about 5 minutes.

The preparation process of the single crystal transition metal sulfur/selenide provided by the invention is simple, and the prepared WS₂The film thickness is 0.8 +/-0.05 nm and the size is 18-300 um. Is more suitable for practical application and has very important practical significance.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a schematic view of the apparatus of the present invention;

FIG. 2a is a temperature profile of zone 1;

FIG. 2b is a temperature profile of zone 2;

FIG. 3a is an optical topography of WS2 on a Si/SiO2(300nm) substrate;

FIG. 3b is Si/SiO₂WS on (2000nm) substrate₂Topography under optics;

FIG. 4 shows WS prepared by the present invention₂XRD pattern of (a).

FIG. 5 shows WS prepared by the present invention₂The photoluminescence map of (a).

Detailed Description

The invention is further explained by the embodiment in the following with the attached drawings.

The examples are given for the purpose of better illustration of the invention, but the invention is not limited to the examples. Therefore, those skilled in the art should make insubstantial modifications and adaptations to the embodiments of the present invention in light of the above teachings and remain within the scope of the invention.

Example 1

Referring to FIG. 1, a high-purity WO, high-purity quartz tube with both ends open, high-purity sulfur in quartz boat, and high-purity quartz tube in large quartz tube with both ends open₃Placing the powder in a quartz boat, placing the powder in a small quartz tube at the middle and downstream, and placing a silicon or silicon dioxide substrate with an oxide layer facing downwards on a quartz boat for placing high-purity WO₃The surface of a powder quartz boat; introducing argon and/or hydrogen from upstream and discharging from downstream; placing high-purity sulfur in a temperature zone1 (Heating zone1), and placing WO₃One end of the powder is a 2 nd temperature zone (Heating zone 2).

EXAMPLE 2 WS on Si/SiO2(300nm) substrate₂Preparation of

According to the structure of example 1, a quartz tube having a length of 100cm and an outer diameter of 7.5mm and opened at both ends was used.

(1) High-purity sulfur with the quantity of 400mg is placed in a quartz boat and is placed at the upstream of a quartz tube; high purity WO in an amount of 20mg₃Placing the powder in a quartz boat, placing the silicon substrate oxide layer surface downwards on the surface of the quartz boat, and placing the quartz boat at the downstream of a quartz tube; the distance between the two quartz boats was 24cm, and the small quartz tube was placed in a large quartz tube having an outer diameter of 25 mm.

(2) And opening a vacuum pump to pump the pressure of the tubular furnace to 4Pa, continuously introducing 400sccm argon until the pressure of the tubular furnace is recovered to normal pressure, opening an air outlet valve and adjusting the argon to 40sccm, keeping a constant value in the heating process, and discharging oxygen in the quartz tube as much as possible.

(3) Opening the tube furnace to start heating, and heating according to the temperature curves shown in fig. 2a and 2b, wherein the first temperature zone is heated to 200 ℃ and the second temperature zone is heated to 850 ℃; immediately adjusting the flow of argon gas to 200sccm, the flow of hydrogen to 5sccm, and maintaining the atmospheric pressure to be normal pressure; grow for 5min under this growth condition.

(4) And immediately turning off heating after the growth is finished, adjusting the hydrogen flow to 0sccm, adjusting the argon flow to 400sccm to flush the quartz tube, opening the hearth, and quickly cooling to room temperature to take out the sample.

Example 3WS₂Morphology and optical Property characterization

(1)WS₂Morphology of

With reference to FIGS. 3a and 3b WS on a Si/SiO2(300nm) substrate₂Topography under light, microscope was produced by jena instruments ltd, germany under the product name Carl Zeiss.

(2)WS₂XRD of

WS prepared in example 2₂The XRD pattern of (A) is shown in FIG. 4, and the X-ray diffractometer is manufactured by Parnake, Netherlands, and has the product name of X' Pert Powder.

(3)WS₂Photoluminescence map of

WS prepared in example 2₂Photoluminescence measurements were performed and the photoluminescence spectra of the measurements are shown in figure 5.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.