Method for preparing rhenium disulfide film by two steps at low pressure

Abstract

The invention discloses a low-pressure two-step preparation method of a rhenium disulfide film, and belongs to the technical field of semiconductor material preparation. In the first step, rhenium powder is partially oxidized to form rhenium / rhenium heptoxide mixed powder. Secondly, rhenium / rhenium heptoxide is used as a rhenium source for rhenium disulfide growth, firstly, the active rhenium heptoxide with the high melting point and the 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 the 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 in two steps at a 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), the rhenium (Re) source is a focus of current research. A good Re source needs to have high reactivity and moderate evaporation rate. Currently, the commonly used Re 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 the 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 the Re 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 low-pressure two-step method for preparing ReS2 thin film. The first step is to form Re / Re2O7 mixed powder by partial oxidation of Re powder; the second step is to use Re / Re2O7 as Re source to grow high-quality ReS2 thin film on a mica substrate, further promoting 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 by two steps at low pressure, comprising 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) Preparation of Re source: a) Weigh the Re powder with an electronic scale, spread the weighed Re powder on a graphite boat, and then place the graphite boat into the central temperature zone of a tube furnace, such as Figure 1b) keep the argon gas at 500sccm for 10min to remove the residual gas in the quartz tube; c) 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 to the Re powder oxidation temperature. The schematic diagram of the device is shown in Figure 2 d) stop argon / oxygen, close both ends of the quartz tube, maintain 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 shown.

[0009] (3) Preparation of ReS2 film: a) Weigh sulfur powder (S) with an electronic scale, and feed the weighed S powder, Re / Re2O7 mixed powder and mica substrate into the first, second and third temperature zones of the tube furnace respectively. Figure 4 As shown; b) Under argon 500sccm, the first, second and third temperature zones are heated to 110°C and kept warm for 10 minutes to remove water vapor; c) Under argon atmosphere, the growth chamber is evacuated to the growth pressure, and then the first, second and third temperature zones are heated to the growth temperature respectively, and then kept warm for the growth time, and finally naturally cooled to room temperature to obtain the ReS2 film.

[0010] Furthermore, in step (2), the mass of Re powder is 10-100 mg.

[0011] Furthermore, in step (2), the argon / oxygen flow rate is 10-100 sccm.

[0012] Furthermore, in step (2), the oxidation pressure is 50-5000Pa.

[0013] Furthermore, in step (2), the oxidation temperature is 400-700°C.

[0014] Furthermore, in step (2), the oxidation time is 5-60 min.

[0015] Furthermore, in step (3), the mass of S powder is 30-2000 mg.

[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 (2), under the action of oxygen heating, by adjusting the flow rate of argon / oxygen, the pressure in the oxygen process, the oxidation temperature and the oxidation time, the oxidation degree of the Re powder can be controlled to obtain mixed powders of Re / Re2O7 with different ratios as the Re source.

[0024] (2) In the present invention, in step (3), Re / Re2O7 is used as the Re source. First, the active, high-melting-point, low-melting-point Re2O7 can be dissolved and reacted with the S powder to generate ReS2 molecules, and 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 the Re 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 a Re source, thus facilitating the synthesis of high-quality ReS2 films.

[0025] (3) 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] (4) 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 a device for preparing a Re source according to the present invention.

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

[0030] Figure 3 It is a schematic diagram of a device for preparing a Re source 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) Preparation of Re source: a) Weigh 30 mg of Re powder using an electronic scale, spread the weighed Re powder evenly on a graphite boat, and then place the graphite boat into the central temperature zone of a tube furnace, such as Figure 1 b) keep the argon gas at 500sccm for 10min to remove the residual gas in the quartz tube; c) stop the argon gas, introduce argon / oxygen mixed gas (oxygen ratio 20%), adjust the gas flow rate and pressure to 50sccm and 1500Pa respectively, and then raise the temperature to 450℃. The schematic diagram of the device is shown in Figure 2 d) stop argon / oxygen, close both ends of the quartz tube, and keep it for 30 minutes to make the Re powder become Re / Re2O7 mixed powder. The schematic diagram of the device is shown in Figure 3 shown.

[0039] (3) Preparation of ReS2 film: a) Weigh 300 mg of S powder using an electronic scale, and place the weighed S powder, Re / Re2O7 mixed powder and mica substrate into the first, second and third temperature zones of the tube furnace respectively. Figure 4 As shown; b) under argon 500sccm, the first, second and third temperature zones are heated to 110°C, kept warm for 10min, and water vapor is removed; c) the argon flow rate and growth pressure are adjusted to 50sccm and 1000Pa respectively, the first, second and third temperature zones are heated to 200°C, 500°C and 900°C, kept warm for 10min, and then naturally cooled to room temperature to obtain ReS2 film.

[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 rhenium disulfide (ReS2) thin film in two steps 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) Preparation of Re source: a) Weigh 10-100 mg of Re powder using an electronic scale, spread the weighed Re powder evenly on a graphite boat, and then place the graphite boat into the central temperature zone of a tube furnace, as shown in FIG1 ; b) Keep the argon gas at 500 sccm for 10 min to remove the residual gas in the quartz tube; c) Stop the argon gas, introduce an argon / oxygen mixed gas (oxygen ratio 20%), adjust the flow rate (10-100 sccm) and pressure (50-5000 Pa) of the argon / oxygen mixed gas, and then raise the temperature to the Re powder oxidation temperature (400-700°C). The schematic diagram of the device is shown in FIG2 ; d) Stop the argon / oxygen, seal both ends of the quartz tube, and keep the oxidation time for 5-60 min to convert the Re powder into a Re / Re2O7 mixed powder. The schematic diagram of the device is shown in FIG3 . (3) Preparation of ReS2 film: a) Weigh 30-2000 mg of S powder using an electronic scale, and send the weighed S powder, Re / Re2O7 mixed powder and mica substrate into the first, second and third temperature zones of the tube furnace, as shown in Figure 4; b) Under argon gas 500sccm, heat the first, second and third temperature zones to 110°C, keep them warm for 10 minutes, and remove water vapor; c) Under argon gas atmosphere (10-200sccm), evacuate the growth chamber to the growth pressure (50-1000Pa), then heat the first, second and third temperature zones to growth temperatures of 150-350°C, 500-850°C and 750-900°C, respectively, and then keep them warm for 5-60 minutes, and finally cool them naturally to room temperature to obtain the ReS2 film.

2. The method for preparing ReS2 thin film in two steps at low pressure according to claim 1, characterized in that: In step (2), under the action of oxygen heating, the oxidation degree of Re powder can be 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 can be obtained as Re sources.

3. The method for preparing ReS2 thin film in two steps at low pressure according to claim 1, characterized in that: In step (3), Re / Re2O7 is used as the Re source. First, the active, high-melting-point, low-melting Re2O7 can be dissolved and reacted with the S powder to generate ReS2 molecules, and then deposited on the mica substrate as a nucleation point 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 the Re source not only utilizes the characteristics of Re2O7 with a low melting point, high activity and easy reaction, but also utilizes the characteristics of Re powder with a high melting point and slow evaporation to continuously provide a Re source, thus facilitating the synthesis of high-quality ReS2 films.

4. The method for preparing ReS2 thin film in two steps 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 in two steps 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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