Method for preparing rhenium disulfide film at low pressure

Abstract

The invention discloses a method for preparing a rhenium disulfide film at low pressure, and belongs to the technical field of semiconductor material preparation. According to the method, rhenium / rhenium heptoxide mixed powder formed by partial oxidation of rhenium powder is used as a rhenium source for rhenium disulfide growth, firstly, rhenium heptoxide with high activity and low melting point can be dissolved to react with sulfur powder to generate rhenium disulfide molecules, and then the rhenium disulfide molecules are deposited on a mica substrate under the leading of argon to serve as nucleation points; then, high-melting-point rhenium powder begins to be dissolved under the assistance of dissolved rhenium heptoxide and is guided by argon to reach the mica substrate to continue growth of rhenium disulfide; and finally, obtaining the high-quality rhenium disulfide film on the mica substrate. The high-quality rhenium disulfide thin film synthesized on the mica substrate is expected to promote further application of the high-quality rhenium disulfide thin film in electrical devices.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor material preparation, and in particular relates to a method for preparing a rhenium disulfide film at low pressure. Background Art

[0002] Two-dimensional transition metal chalcogenides (TMDCs) are a class of layered materials that are connected by covalent bonds in the plane and interact with each other by van der Waals forces. Among the many two-dimensional TMDCs materials, rhenium disulfide (ReS2) has an asymmetric crystal structure, and its in-plane anisotropic optical and electrical properties and excellent environmental stability make it have potential application value in the fields of polarization photodetection devices.

[0003] In the preparation of ReS2 by chemical vapor deposition (CVD), rhenium source is a focus of current research. A good rhenium (Re) source needs to have high reactivity and moderate evaporation rate. Commonly used rhenium sources include mixtures of rhenium and tellurium, rhenium oxides, etc., but there are still some problems in controllability. For example, when rhenium heptoxide (Re2O7) is used as a rhenium source, although the reactivity is high, Re2O7 evaporates easily, resulting in a large nucleation density and easy formation of particles rather than films. Therefore, the optimization of rhenium source is a key issue in the study of CVD preparation of ReS2 thin films, which has important research significance for both basic research and practical applications of ReS2 thin films. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing ReS2 thin film, by partially oxidizing Re powder to form Re / Re2O7 mixed powder as a rhenium source, on this basis to obtain high-quality ReS2 thin film, and further promote its application in electrical devices.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for preparing a ReS2 thin film at low pressure comprises the following steps:

[0007] (1) Cleaning the graphite boat and substrate: respectively place the graphite boat and mica substrate in acetone ultrasonic bath for 15 min, anhydrous ethanol for 15 min, and deionized water for 15 min, and blow dry with a nitrogen gun.

[0008] (2) Weigh sulfur powder (S) with an electronic scale and place it in a graphite boat; weigh Re powder with an electronic scale and spread the weighed Re powder on a second graphite boat; place a mica substrate on a third graphite boat; and sequentially place the three graphite boats into a quartz tube. The schematic diagram of the device is shown in FIG. Figure 1 shown.

[0009] (3) Preparation of ReS2 film: a) Keep the argon gas at 500 sccm for 10 min to remove the residual gas in the quartz tube; b) Stop the argon gas, introduce argon / oxygen mixed gas (oxygen ratio 20%), adjust the flow rate and pressure of the argon / oxygen mixed gas, and then raise the temperature of the second temperature zone to the oxidation temperature of Re powder. The schematic diagram of the device is shown in Figure 2 c) stop argon / oxygen, close both ends of the quartz tube, keep a certain oxidation time, so that the Re powder becomes Re / Re2O7 mixed powder, the schematic diagram of the device is as shown Figure 3 d) inputting a certain growth flow rate of argon gas and setting the growth pressure, heating the first, second and third temperature zones to the growth temperature, keeping the growth time, and then naturally cooling to room temperature to obtain the ReS2 film. The schematic diagram of the device is shown in Figure 4 shown.

[0010] Furthermore, in step (2), the mass of S powder is 30-2000 mg.

[0011] Furthermore, in step (2), the mass of Re powder is 10-100 mg.

[0012] Furthermore, in step (3), the argon / oxygen flow rate is 10-100 sccm.

[0013] Furthermore, in step (3), the oxidation pressure is 50-5000Pa.

[0014] Furthermore, in step (3), the oxidation temperature in the second temperature zone is 400-700°C.

[0015] Furthermore, in step (3), the oxidation time is 5-30 min.

[0016] Furthermore, in step (3), the argon growth flow rate is 10-200 sccm.

[0017] Furthermore, in step (3), the growth pressure is 50-1000Pa.

[0018] Furthermore, in step (3), the growth temperature in the first temperature zone is 150-350°C.

[0019] Furthermore, in step (3), the growth temperature in the second temperature zone is 500-850°C.

[0020] Furthermore, in step (3), the growth temperature in the third temperature zone is 750-900°C.

[0021] Furthermore, in step (3), the growth time is 5-60 min.

[0022] In summary, by adopting the above technical solution, the beneficial effects of the present invention are:

[0023] (1) In the present invention, in step (3), under the action of oxygen heating, the oxidation degree of Re powder is controlled by adjusting the flow rate of argon / oxygen, the pressure in the oxygen process, the oxidation temperature and the oxidation time, and mixed powders of Re / Re2O7 with different ratios are obtained as rhenium sources.

[0024] (2) In the present invention, in step (3), Re / Re2O7 is used as the rhenium source. First, the active, high-melting-point, low-melting-point Re2O7 can be dissolved and reacted with the S powder to generate ReS2 molecules, which are then deposited on the mica substrate as nucleation points under the guidance of argon gas; then the high-melting-point Re powder begins to dissolve with the assistance of the dissolved Re2O7, and continues to grow ReS2 on the mica substrate under the guidance of argon gas; finally, a high-quality ReS2 film is obtained on the mica substrate. The design of this composite rhenium source not only utilizes the characteristics of Re2O7 with low melting point, high activity and easy reaction, but also utilizes the characteristics of Re powder with high melting point and slow evaporation to continuously provide rhenium source.

[0025] (4) In the present invention, the low-pressure vacuum vapor deposition method (pressure 50-1000Pa) is used, which is conducive to the migration and growth of ReS2 molecules on the mica substrate, so that the prepared ReS2 film has the advantages of large area and consistency.

[0026] (5) In the present invention, the number of layers of the ReS2 film can be controlled by the Re quality in step (2) and the growth time in step (3). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a schematic diagram of the device for preparing ReS2 thin film according to the present invention.

[0029] Figure 2 It is a schematic diagram of the device for preparing ReS2 thin film according to the present invention.

[0030] Figure 3 It is a schematic diagram of the device for preparing ReS2 thin film according to the present invention.

[0031] Figure 4 It is a schematic diagram of the device for preparing ReS2 thin film according to the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0034] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0035] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0036] Example 1

[0037] (1) Cleaning the graphite boat and substrate: Separately clean the graphite boat and ~1×1 cm 2 The mica substrate was placed in acetone ultrasound for 15 min, anhydrous ethanol for 15 min, deionized water for 15 min, and dried with a nitrogen gun.

[0038] (2) Weigh 200 mg of S powder using an electronic scale and place it in a graphite boat; weigh 20 mg of Re powder using an electronic scale and spread the weighed Re powder on a second graphite boat; place the mica substrate on a third graphite boat; and place the above three graphite boats into the quartz tube in sequence. The schematic diagram of the device is shown in FIG. Figure 1 shown.

[0039] (3) Preparation of ReS2 thin film: a) Keep the argon gas at 500 sccm for 10 min to remove the residual gas in the quartz tube; b) Stop the argon gas, introduce argon / oxygen mixed gas (oxygen ratio 20%), adjust the gas flow rate and pressure to 30 sccm and 1000 Pa respectively, and then raise the temperature of the second temperature zone to 450°C. The schematic diagram of the device is shown in the figure. Figure 2 c) stop argon / oxygen, close both ends of the quartz tube, keep the oxidation time for 25min, so that the Re powder becomes Re / Re2O7 mixed powder, the schematic diagram of the device is as shown Figure 3 d) introducing argon gas, adjusting the gas flow rate and growth pressure to 50sccm and 2000Pa, raising the temperatures of the first, second and third temperature zones to 200°C, 600°C and 850°C, keeping the temperatures for 10 minutes, and then cooling naturally to room temperature to obtain a ReS2 film. The schematic diagram of the device is shown in Figure 4 shown.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a rhenium disulfide (ReS2) thin film at low pressure, comprising the following steps: (1) Cleaning the graphite boat and substrate: respectively place the graphite boat and mica substrate in acetone ultrasonic bath for 15 min, anhydrous ethanol for 15 min, and deionized water for 15 min, and blow dry with a nitrogen gun. (2) Weigh sulfur powder (S) using an electronic scale and place it in a graphite boat; weigh rhenium (Re) powder using an electronic scale and spread the weighed Re powder evenly on a second graphite boat; place a mica substrate on a third graphite boat; and sequentially place the three graphite boats into a quartz tube. The schematic diagram of the device is shown in FIG1 . (3) Preparation of ReS2 film: a) Maintaining argon at 500 sccm for 10 min to remove residual gas in the quartz tube; b) Stopping argon, introducing argon / oxygen mixed gas (oxygen ratio 20%), adjusting the flow rate and pressure of the argon / oxygen mixed gas, and then heating the second temperature zone to the Re powder oxidation temperature. The schematic diagram of the device is shown in FIG2 ; c) Stopping argon / oxygen, sealing both ends of the quartz tube, and maintaining a certain oxidation time to convert the Re powder into a Re / Re2O7 mixed powder. The schematic diagram of the device is shown in FIG3 ; d) Inputting a certain growth flow rate of argon and setting the growth pressure, heating the first, second and third temperature zones to the growth temperature, maintaining the growth time, and then naturally cooling to room temperature to obtain a ReS2 film. The schematic diagram of the device is shown in FIG4 .

2. The method for preparing ReS2 thin film at low pressure according to claim 1, characterized in that: In step (3), under the action of oxygen heating, the oxidation degree of Re powder is controlled by adjusting the flow rate of argon / oxygen, the pressure in the oxygen process, the oxidation temperature and the oxidation time, and mixed powders of Re / Re2O7 with different proportions are obtained as rhenium sources.

3. The method for preparing ReS2 thin film at low pressure according to claim 1, characterized in that: In step (3), Re / Re2O7 is used as the rhenium source. First, the active, high-melting-point, low-melting Re2O7 can be dissolved and reacted with the S powder to generate ReS2 molecules, which are then deposited on the mica substrate as nucleation points under the guidance of argon gas. Then, the high-melting-point Re powder begins to dissolve with the assistance of the dissolved Re2O7, and continues to grow ReS2 on the mica substrate under the guidance of argon gas. Finally, a high-quality ReS2 film is obtained on the mica substrate. This design of a composite rhenium source not only utilizes the characteristics of Re2O7's low melting point, high activity, and easy reaction, but also utilizes the characteristics of Re powder's high melting point and slow evaporation to continuously provide a rhenium source.

4. The method for preparing ReS2 thin film at low pressure according to claim 1, characterized in that: The low-pressure vacuum vapor deposition method (pressure 50-1000Pa) used is conducive to the migration and growth of ReS2 molecules on the mica substrate, so that the prepared ReS2 film has the advantages of large area and consistency.

5. The method for preparing ReS2 thin film at low pressure according to claim 1, characterized in that: The number of layers of the ReS2 film can be controlled by the Re quality in step (2) and the growth time in step (3).

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