A two-dimensional atomically flat platinum disulfide material, method of preparation and use
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JISHI CORE MATERIAL (HANGZHOU) TECHNOLOGY CO LTD
- Filing Date
- 2025-07-07
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies make it difficult to achieve the controllable growth of high-quality, pure-phase, large-area two-dimensional planar layered PtS2 thin films, leading to problems such as enhanced electron scattering, reduced mobility, material heating, and reduced photoelectric conversion efficiency in nanoparticle PtS2 materials in devices.
Two-dimensional atomically flat platinum disulfide materials were prepared by thermally assisted conversion on platinum thin films, controlling the volume concentration of sulfur vapor and the heating rate. A specific heating and holding procedure was used to induce the formation of uniformly distributed nucleation sites, avoiding local agglomeration or pore defects, and achieving two-dimensional planar spreading.
A two-dimensional PtS2 thin film with atomic-level surface smoothness was obtained, which improved the sensitivity and photoelectric conversion efficiency of the device, reduced the channel size, enhanced the contact with the electrode, and realized the high responsivity and fast response of the broadband photodetector.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of optoelectronic materials, specifically relating to a two-dimensional atomically flat platinum disulfide material, its preparation method, and its applications. Background Technology
[0002] Broadband photodetectors (BPDs) can detect optical signals across a multi-wavelength range and have significant applications in security, communications, sensing, and medical imaging. Platinum disulfide (PtS2), with its unique electronic structure and optical properties, has become one of the most promising materials for broadband photodetectors. The complete occupation of d-orbital electrons in Pt atoms endows PtS2 with a wide-tunable bandgap, ranging from the visible light region (1.6 eV for monolayers) to the infrared region (IR, 0.25 eV for multilayers).
[0003] Thermally assisted conversion of specific metal thin films via CVD is a common method for preparing wafer-level uniform thin films, as verified in the preparation of materials such as PtSe2, PtTe2, WTe2, and PdTe2. Sulfidation of Pt thin films is a common method for synthesizing high-quality PtS2 crystals. However, due to the high chemical stability and Rayleigh instability of Pt atoms, as well as the disproportionation reaction of Pt thin films, the synthesized PtS2 is usually in the form of nanoparticles, or mainly forms thermodynamically favorable non-layered PtS crystals. When nanoparticle PtS2 is used in device fabrication, the physical gaps between particles are much larger than the electron diffusion free path, resulting in large resistance values between the particles. This leads to various drawbacks such as enhanced electron scattering, reduced mobility, material heating, and reduced photoelectric conversion efficiency, thus affecting the detection reliability and sensitivity of the device.
[0004] Therefore, how to achieve the controllable growth of high-quality, pure-phase, large-area two-dimensional (2D) planar layered PtS2 thin films is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0005] To address the shortcomings of existing technologies, one objective of this invention is to provide a two-dimensional atomically flat platinum disulfide material with a two-dimensional planar spread structure and an atomically flat surface. The thickness of the two-dimensional atomically flat platinum disulfide material is 2–12 nm, such as 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, etc.
[0006] The atomic-level flatness can be understood as the range of its surface roughness being less than or equal to the size of the unit cell of a large planar spread structure. The two-dimensional atomically flat platinum disulfide material provided in this application has a thickness of 2–31 nm and a spread structure with atomic-level flatness on a two-dimensional plane. This will reduce the thickness of the device, improve the continuity of the film layer, increase the good contact with the electrode, improve the sensitivity of the device, and further reduce the channel size.
[0007] The atomic-level flatness described in this application can be understood as roughness less than or equal to the size of the material's constituent unit cell. For example, the planar roughness of a two-dimensional atomically flat platinum disulfide material is less than or equal to the size of the platinum disulfide unit cell or the thickness of a single layer of platinum disulfide, approximately 0.7 nm.
[0008] Preferably, the platinum disulfide material is capable of being at least 15 μm thick. 2 The root mean square surface roughness is maintained at 0.26–0.67 nm within the range, for example, 0.27 nm, 0.29 nm, 0.34 nm, 0.38 nm, 0.43 nm, 0.46 nm, 0.50 nm, 0.55 nm, 0.63 nm, 0.65 nm, etc.
[0009] The root mean square surface roughness described in this application is R. q It is calculated using the following formula:
[0010]
[0011] Z i Z represents the height value of the i-th data point. ave Let i be the average height of all data points in the test space, and let N be the number of test data points. Both N and i are positive integers.
[0012] Preferably, the platinum disulfide material can be used at least 26 cm 2 Maintain a root mean square surface roughness of 0.26–0.67 nm within an area of approximately 2 inches × 2 inches.
[0013] Preferably, the platinum disulfide material has a polycrystalline orientation structure characterized by a triple-symmetric pure 2H phase.
[0014] The polycrystalline orientation structure of the triple-symmetric pure 2H phase can be understood as a polycrystalline orientation structure formed by the overlapping of two-dimensional platinum disulfide unit cells after they have grown along a two-dimensional plane.
[0015] The second objective of this application is to provide a method for preparing a two-dimensional, atomically flat platinum disulfide material, comprising the following steps:
[0016] (1) Provide a platinum thin film as a substrate, denoted as platinum substrate;
[0017] (2) Platinum substrate is placed in an inert gas dispersion system of sulfur vapor, and the platinum substrate is heated in a programmed atmosphere of sulfur vapor to obtain a two-dimensional atomically flat platinum disulfide material.
[0018] In the inert gas dispersion system of sulfur vapor, the volume concentration of sulfur vapor is 15–20 g / m³. 3 For example, 16g / m 3 17g / m 3 18g / m 3 19g / m 3 wait;
[0019] The starting temperature of the programmed temperature rise is 110–130°C, the ending temperature of the programmed temperature rise is 580–630°C, the heating rate is 2–4°C / min, and the temperature at the ending temperature is held for 50–70 min.
[0020] The preparation method described in the second objective of this application is one of the preparation methods for the two-dimensional atomically flat platinum disulfide material described in the first objective of this application.
[0021] This application utilizes platinum thin films as a basis to achieve a two-dimensional, atomically flat platinum disulfide material through thermally assisted conversion under a specific sulfur environment. Specifically, the volume concentration of sulfur vapor ensures the selective proportion of platinum disulfide in the disproportionation reaction of the Pt film. This is because the specific sulfur vapor volume concentration allows the platinum film to contact sufficient sulfur vapor and promotes the diffusion of sulfur atoms into the bulk phase of the Pt film, reacting to form platinum disulfide. On the other hand, a specific heating and holding procedure reduces the formation of nanoparticle-like PtS2, instead forming a two-dimensional, atomically flat platinum disulfide material. Platinum materials, with sufficient sulfur involved, have their heating rate limited to the range of 2–4 °C / min. This allows the platinum film to undergo a controlled kinetic process during the initial sulfurization stage, inducing the formation of uniformly distributed two-dimensional nucleation sites. This avoids local agglomeration or void defects caused by sudden temperature changes. In other words, a heating rate of 2–4 °C / min facilitates the two-dimensional planar spread of PtS2. Based on these nucleation sites, PtS2 is driven to grow epitaxially along the two-dimensional plane by optimizing the termination temperature until adjacent crystal domains join to form continuous grain boundaries, ultimately obtaining a large-area two-dimensional PtS2 crystalline film.
[0022] Preferably, the thickness of the platinum substrate is 1 to 6 nm, such as 1.1 nm, 1.5 nm, 2.0 nm, 2.5 nm, 3.2 nm, 3.9 nm, 4.4 nm, 5.0 nm, 5.6 nm, etc.
[0023] Since the platinum disulfide material provided in this application is grown in situ on a platinum thin film, a suitable platinum substrate thickness will facilitate the penetration of sulfur atoms and controllably form a two-dimensional PtS2 thin film. If the platinum thin film is too thick (e.g., greater than 6 nm), the penetration amount of sulfur atoms in the surface platinum and the bottom platinum will be different, which will make the bottom platinum more likely to form PtS material, reducing the purity of platinum disulfide. If the platinum thin film is too thin (e.g., less than 1 nm), it will lead to discontinuous growth of the film.
[0024] Preferably, the platinum substrate is obtained by magnetron sputtering or atomic layer deposition.
[0025] Preferably, placing the platinum substrate in an inert gas dispersion system of sulfur vapor includes:
[0026] A reaction vessel is provided, in which a platinum substrate and a sulfur source are placed respectively. The reaction vessel is placed in an inert gas atmosphere and heated until the sulfur source vaporizes into sulfur vapor.
[0027] It should be noted that the reaction vessel should be understood as a reaction vessel that has undergone inert gas purging.
[0028] In the aforementioned scheme of "placing the platinum substrate in an inert gas dispersion system of sulfur vapor", the platinum substrate and the sulfur source are placed together in the same reaction vessel. The location of the sulfur source in the reaction vessel is heated to the sulfur vaporization temperature of 200°C, and the sulfur concentration in the reaction vessel rapidly reaches 15-20 g / m³. 3 The concentration of the platinum substrate is simultaneously increased to 580-630°C at a rate of 2-4°C / min, and a preliminary sulfidation reaction with the platinum film occurs, forming a structure similar to a crystal nucleus. During this process, the amount of gas in the reaction vessel changes and needs to be exchanged with the external environment. Therefore, the reaction vessel needs to be placed in an inert atmosphere to ensure the normal sulfidation of the platinum film.
[0029] In an alternative embodiment, the reaction vessel may undergo a small amount of gas exchange with an inert atmosphere.
[0030] Preferably, the inert gas atmosphere includes an inert gas passage.
[0031] Preferably, the reaction vessel includes either a quartz tube with a quartz plug or a quartz tube with a flow-limited opening.
[0032] Preferably, the inert gas includes any one or a combination of at least two of argon and helium.
[0033] Preferably, the side length of the platinum substrate is optionally any size from 0.5cm to 5.5cm (e.g., 0.5cm×0.5cm, 2 inches×2 inches, etc.), and the amount of sulfur powder added is 200 to 300mg, such as 220mg, 250mg, 270mg, 290mg, etc.
[0034] As one of the preferred technical solutions, the preparation method includes the following steps:
[0035] (1) A platinum thin film is sputtered on the surface of a SiO2 / Si substrate by magnetron sputtering as a substrate, denoted as platinum substrate;
[0036] (2) Place the platinum substrate in a tubular single-opening quartz container and place sulfur powder on the side of the platinum substrate near the opening;
[0037] (3) Use a quartz plug to seal the opening of the quartz container, but leave a gap, and place the quartz container in an inert atmosphere to grow a two-dimensional atomically flat platinum disulfide thin film material by heating from room temperature to the termination temperature at a rate of 2-4℃ / min.
[0038] The third objective of this application is to provide an application for the two-dimensional atomically flat platinum disulfide material as described in the first objective, wherein the two-dimensional atomically flat platinum disulfide material is used in any one of field-effect transistors and photodetectors, preferably in any one of broadband photodetectors, and more preferably in any one of broadband photodetectors at room temperature.
[0039] The fourth objective of this application is to provide a photoelectric responsive continuous film device, comprising:
[0040] Substrate layer;
[0041] A two-dimensional, atomically flat platinum disulfide material, as described in one of the objectives, is disposed on the substrate.
[0042] An electrode layer disposed on a two-dimensional, atomically flat platinum disulfide material;
[0043] Preferably, the substrate layer includes any one of SiO2 / Si substrate and sapphire substrate;
[0044] Preferably, the electrode layer includes a chromium layer close to the platinum disulfide material and a gold layer disposed on the side of the chromium layer away from the two-dimensional atomically flat platinum disulfide material.
[0045] The photoresponse continuous film device described in this application exhibits photoresponse under irradiation at wavelengths from 500 to 2200 nm, with a response time of less than 1 s, especially less than 0.5 s, and can be used as a broadband photodetector.
[0046] Compared with the prior art, this application has the following beneficial effects:
[0047] (1) The two-dimensional atomically flat platinum disulfide material provided in this application has a thickness of 2 to 12 nm and has an atomically flat spreading structure on a two-dimensional plane. This will reduce the thickness of the device, improve the continuity of the film layer, increase the good contact with the electrode, improve the sensitivity of the device, and further reduce the channel size. The two-dimensional atomically flat platinum disulfide material provided in this application has high platinum disulfide purity, and the photoresponse wavelength can reach 500 to 2200 nm with a response time of less than 1 s.
[0048] (2) The preparation method of the two-dimensional atomic-level flat platinum disulfide material provided in this application solves the technical problems of platinum disulfide not being able to be laid flat in two dimensions due to Rayleigh instability and the low purity of platinum disulfide caused by the disproportionation of Pt thin film sulfidation. Attached Figure Description
[0049] Figure 1 The Raman spectrum of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1 is shown.
[0050] Figure 2 Raman intensity image of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1;
[0051] Figure 3 Macroscopic photograph of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1;
[0052] Figure 4 Optical microscope characterization of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1;
[0053] Figure 5 An atomic force microscope image of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1;
[0054] Figure 6 The images shown are transmission electron microscopy (HRTEM) characterization images of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1, where image a is a 100 nm scale image and image b is a magnification of the dashed box area in image a.
[0055] Figure 7 The selected area electron diffraction (SAED) characterization patterns of the two-dimensional, atomically flat platinum disulfide thin film material prepared in Example 1 are shown in Figures a and b, respectively. Figure 6 The corresponding letter-labeled areas in Figure b;
[0056] Figure 8 The Raman spectrum characterization of the thin film obtained in Comparative Example 4 is shown below.
[0057] Figure 9 The Raman spectrum characterization of the thin film obtained in Comparative Example 5 is shown below.
[0058] Figure 10 An optical microscope image of the photoelectric response continuous film device provided in Application Example 1;
[0059] Figure 11 The output characteristic curve (a) and transfer curve (b) of the PtS2 field-effect transistor FET with a source-drain voltage of -6 to 6V for the photoelectric response continuous film device prepared in Example 1 at room temperature are shown.
[0060] Figure 12 The photoresponse curves of the photoresponse continuous film devices prepared in Application Example 1 and Comparative Examples 1 and 2 under laser irradiation at 532 nm, 980 nm, 1550 nm, 1850 nm and 2200 nm are shown.
[0061] Figure 13 The image shows the photoresponse time of the three devices in Application Example 1 and Comparative Examples 1 and 2 under 1550nm illumination. Detailed Implementation
[0062] The technical solution of the present invention will be further explained and described below with reference to specific embodiments. However, it should be noted that the specific embodiments are only a specific implementation and explanation of the essence of the technical solution of the present invention, and should not be construed as a limitation on the scope of protection of the present invention.
[0063] The reagents and instruments used in the examples are all commercially available, and the preparation method described is a conventional method well known in the art.
[0064] Example 1
[0065] A method for preparing a two-dimensional, atomically flat platinum disulfide thin film material includes the following steps:
[0066] (1) A 1.0 nm thick platinum thin film was sputtered onto the surface of a SiO2 / Si substrate (1 cm × 1.5 cm) by magnetron sputtering, denoted as the platinum substrate. The specific operation was as follows: the cleaned SiO2 / Si substrate and the platinum target were placed into the magnetron sputtering cavity, and the cavity vacuum was evacuated to 1 × 10⁻⁶. -5 Below Pa; pre-sputter for 1 min to remove impurities from the target surface, then open the baffle between the target and the substrate; with Sputtered at a rate to a thickness of 1 nm;
[0067] (2) Place the platinum substrate in a tubular single-opening quartz container (35cm long and 2cm in diameter), and place 250mg of sulfur powder 6cm away from the opening side of the platinum substrate.
[0068] (3) Seal the opening of the quartz container with a quartz stopper, leaving a gap, and place the quartz container in an argon atmosphere in the CVD pipeline. The temperature is increased from room temperature (25°C) to the final temperature (600°C) at a rate of 3°C / min. At this point, the sulfur vapor concentration is 15 g / m³. 3 Then, a two-dimensional atomically flat platinum disulfide thin film material is grown by holding it at 600℃ for 60 minutes. It has a two-dimensional planar spreading structure and its planar spreading surface has atomic-level flatness.
[0069] Performance characterization:
[0070] (i) Raman spectroscopy: The testing equipment was a Bruker RFS100 / S Raman spectrometer with a laser wavelength of 532 nm;
[0071] Raman spectroscopy characterization results are as follows Figure 1 ( Figure 1 The Raman spectrum of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1 is shown below. It can be seen that the image is located at 302.3 cm⁻¹. -1 334.4cm -1 and 342.6cm -1 The characteristic peaks at these locations correspond to the E values of PtS2. g 1 A 1g 1 and A 1g 2 The vibrational modes confirmed that the competing product, PtS crystal, had been effectively suppressed, and pure-phase PtS2 crystal was successfully synthesized.
[0072] Raman intensity image as shown Figure 2 ( Figure 2 As shown in the Raman intensity image of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1, it can be seen that E g 1 and A 1g 1 +A 1g 2 The Raman intensity imaging of the composite mode showed uniform color contrast, indicating that the PtS2 film has high uniformity.
[0073] (ii) Macro photos
[0074] Figure 3 The image shows a macroscopic photograph of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1, which can be seen to have a continuous thin film structure on a macroscopic scale.
[0075] (iii) Optical microscope: The testing equipment was an Olympus BX51 optical microscope;
[0076] Optical microscopy characterization results as follows Figure 4 ( Figure 4 The image shown is an optical microscope characterization of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1. It can be seen that the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1 is a large-area continuous uniform film.
[0077] (iii) Atomic force microscopy: The testing equipment was a Bruker Multimode 8 atomic force microscope;
[0078] Atomic force microscopy characterization results as follows Figure 5 ( Figure 5 The image shown is an atomic force microscope characterization of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1. It can be seen that the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1 has large-area uniformity, a thickness of 4.6 nm, and a surface roughness of 0.42 nm.
[0079] (iv) Transmission electron microscopy: The testing equipment was a FEITecnaiG2 F30 transmission electron microscope;
[0080] Transmission electron microscopy characterization results as follows Figure 6 ( Figure 6 Image b is a transmission electron microscope (HRTEM) characterization image of the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1 (where image b is an enlarged version of the dashed box area in image a). Figure 7 ( Figure 7 The selected area electron diffraction (SAED) characterization patterns of the two-dimensional, atomically flat platinum disulfide thin film material prepared in Example 1 are shown in Figures a and b, respectively. Figure 6 As can be seen from the corresponding letter markings in Figure b, the two-dimensional atomically flat platinum disulfide thin film material prepared in Example 1 has a horizontally layered continuous thin film structure in a two-dimensional plane, indicating that the nanoparticles have been well suppressed; the lattice spacing is 0.31 nm, which is consistent with the crystal plane parameters of PtS2 crystal (100); the SAED spectrum shows highly consistent triple symmetry features and constant lattice parameters, further confirming that the film has a polycrystalline orientation structure with triple symmetry pure 2H phase.
[0081] Example 2
[0082] A method for preparing a two-dimensional, atomically flat platinum disulfide thin film material includes the following steps:
[0083] (1) A 6 nm thick platinum thin film was sputtered onto the surface of a SiO2 / Si substrate (1 cm × 1.5 cm) by magnetron sputtering, which is referred to as the platinum substrate. The specific operation is as follows: the cleaned SiO2 / Si substrate and the platinum target are placed into the magnetron sputtering cavity, and the cavity vacuum is evacuated to 1 × 10⁻⁶. -5 Below Pa; pre-sputter for 1 min to remove impurities from the target surface, then open the baffle between the target and the substrate; with Sputtered at a rate to a thickness of 6 nm;
[0084] (2) Place the platinum substrate in a tubular single-opening quartz container (35cm long and 2cm in diameter), and place 200mg of sulfur powder 8cm away from the opening side of the platinum substrate.
[0085] (3) Seal the opening of the quartz container with a quartz stopper, leaving a gap, and place the quartz container in an argon atmosphere in the CVD pipeline. The temperature is increased from room temperature (25°C) to the final temperature (580°C) at a rate of 2°C / min. At this point, the sulfur vapor concentration is 20 g / m³. 3 Then, a two-dimensional atomically flat platinum disulfide thin film material with a thickness of 30.5 nm and a roughness of 0.63 nm is grown by holding it at 580℃ for 50 min. It has a two-dimensional planar spreading structure and its planar spreading surface has atomic-level flatness.
[0086] Example 3
[0087] A method for preparing a two-dimensional, atomically flat platinum disulfide thin film material includes the following steps:
[0088] (1) A 4 nm thick platinum thin film was sputtered onto the surface of a SiO2 / Si substrate (1 cm × 1.5 cm) by magnetron sputtering, denoted as the platinum substrate. The specific operation was as follows: the cleaned SiO2 / Si substrate and the platinum target were placed into the magnetron sputtering cavity, and the cavity vacuum was evacuated to 1 × 10⁻⁶. -5 Below Pa; pre-sputter for 1 min to remove impurities from the target surface, then open the baffle between the target and the substrate; with Sputtered at a rate to a thickness of 4 nm;
[0089] (2) Place the platinum substrate in a tubular single-opening quartz container (35cm long and 2cm in diameter), and place 300mg of sulfur powder 8cm away from the opening side of the platinum substrate.
[0090] (3) The opening of the quartz container is plugged with a quartz stopper, but a gap is left. The quartz container is then placed in an argon atmosphere in the CVD pipeline and heated from room temperature (25°C) to a final temperature of 630°C at a rate of 4°C / min. At this point, the sulfur vapor concentration is 17 g / m³. 3Then, a two-dimensional atomically flat platinum disulfide thin film material with a thickness of 20.1 nm and a roughness of 0.49 nm is grown by holding at 630℃ for 70 min. It has a two-dimensional planar spreading structure and its planar spreading surface has atomic-level flatness.
[0091] Example 4
[0092] A method for preparing a two-dimensional, atomically flat platinum disulfide thin film material includes the following steps:
[0093] (1) A 1.0 nm thick platinum thin film was sputtered onto the surface of a SiO2 / Si substrate (2-inch wafer) using magnetron sputtering as the substrate, denoted as the platinum substrate; the specific operation was as follows: the cleaned SiO2 / Si substrate and the platinum target were placed into the magnetron sputtering cavity, and the cavity vacuum was evacuated to 1×10 -5 Below Pa; pre-sputter for 1 min to remove impurities from the target surface, then open the baffle between the target and the substrate; with Sputtered at a rate to a thickness of 1 nm;
[0094] (2) Place the platinum substrate in a tubular single-opening quartz container (35cm long, 6cm diameter at the opening), and place 250mg of sulfur powder 10cm away from the opening side of the platinum substrate. The sulfur vapor concentration is 15g / m³. 3 ;
[0095] (3) Use a quartz plug to seal the opening of the quartz container, but leave a gap, and place the quartz container in the argon atmosphere of the CVD pipeline to raise the temperature from room temperature 25°C to the final temperature 600°C at a rate of 3°C / min. Then hold at 600°C for 60 min to grow a two-dimensional atomically flat platinum disulfide thin film material with a thickness of 4.4 nm and a roughness of 0.32 nm. It has a two-dimensional planar spreading structure and its planar spreading surface has atomic flatness.
[0096] Comparative Example 1
[0097] A method for preparing a platinum disulfide thin film differs from Example 1 only in that the heating rate in step (3) is adjusted from 3℃ / min to 6℃ / min, and the obtained platinum disulfide thin film has a thickness of 5.0nm and a roughness of 1.43nm.
[0098] Comparative Examples 2-3
[0099] A method for preparing a platinum disulfide thin film differs from Example 1 only in that the termination temperature of step (3) is adjusted from 600°C to 550°C (Comparative Example 2) and 650°C (Comparative Example 3).
[0100] The platinum disulfide film obtained in Comparative Example 2 had a thickness of 5.1 nm and a roughness of 0.98 nm.
[0101] The platinum disulfide film obtained in Comparative Example 3 had a thickness of 5.2 nm and a roughness of 2.18 nm.
[0102] Comparative Examples 4-5
[0103] A method for preparing a thin film differs from Example 1 only in that the sulfur powder in step (2) is adjusted from 250 mg to 160 mg, and the volume concentration of sulfur vapor is adjusted from 15 g / m³. 3 Adjusted to 10g / m 3 (Comparative Example 4); and the sulfur powder in step (2) was adjusted from 250 mg to 80 mg, and the volume concentration of sulfur vapor was adjusted from 15 g / m³. 3 Adjusted to 5g / m 3 (Comparative Example 5)
[0104] The Raman spectral characterization results of the thin film obtained in Comparative Example 4 are as follows: Figure 8 ( Figure 8 The Raman spectrum of the thin film obtained in Comparative Example 4 is shown in the figure. The characteristic peak is at 300.1 cm⁻¹. -1 and 331.8cm -1 E corresponding to PtS2 g 1 Vibration modes and B of PtS 1g The vibrational mode indicates the formation of a PtS2 / PtS mixed-phase crystal.
[0105] The Raman spectral characterization results of the platinum thin film obtained in Comparative Example 5 are as follows: Figure 9 ( Figure 9 The Raman spectrum of the thin film obtained in Comparative Example 5 is shown in the figure. The characteristic peak is at 332.6 cm⁻¹. -1 B corresponding to PtS 1g The vibrational mode indicates the formation of a PtS crystal.
[0106] As can be seen from the examples and comparative examples, the preparation method provided in this application can obtain a two-dimensional planar spread platinum disulfide material with atomic-level surface smoothness. In the preparation method of the two-dimensional planar spread platinum disulfide material with atomic-level surface smoothness, it is necessary to control the volume concentration of sulfur vapor and the heating program.
[0107] Application Example 1 and Comparative Examples 1 and 2
[0108] A photoelectric responsive continuous film device is fabricated by the following method:
[0109] (1) On one side of the platinum disulfide film layer of the structures provided in the application examples and comparative examples (hereinafter referred to as samples), a PMMA coating was spin-coated using a spin coater and heated to form a support film. Then, the sample was immersed in ultrapure water to separate the PMMA support film adhering to the sample from the SiO2 / Si substrate. Finally, the PMMA film adhering to the sample was separated from the old substrate and then adhered to a new SiO2 / Si substrate.
[0110] (2) Using a copper mesh as a mask, electrode materials (Cr and Au) are deposited on the sample surface by thermal evaporation in an electrode area of 50 μm × 50 μm and a channel size of 20 μm, forming a continuous photoelectric response film device of sample film-chromium electrode / gold electrode. The sample film in Application Example 1 uses a two-dimensional atomically flat platinum disulfide film material obtained in Example 1. The sample film in Comparative Application Example 1 uses a two-dimensional PtS2 / PtS film obtained in Comparative Example 4. The sample film in Comparative Application Example 2 uses a two-dimensional PtS film obtained in Comparative Example 5.
[0111] Figure 10 An optical microscope image of the photoelectric response continuous film device provided in Application Example 1 is given.
[0112] For the optoelectronic device obtained in Application Example 1, photoelectric response testing was performed: the testing equipment was a Keithely 2614b semiconductor analysis vacuum probe station;
[0113] Figure 11 The output characteristic curves (a) and transfer curves (b) of the PtS2 field-effect transistor FET prepared in Example 1 at room temperature with source-drain voltages of -6 to 6V are shown. Curve a shows that it exhibits a good linear relationship, indicating that a good ohmic contact is formed between the PtS2 thin film and the electrode. Curve b shows that the device has current flowing in the gate voltage range of -60V to 60V.
[0114] Figure 12 The photoresponse curves of the photoresponse continuous film devices prepared in Application Example 1 and Comparative Examples 1 and 2 under laser irradiation at 532 nm, 980 nm, 1550 nm, 1850 nm and 2200 nm are shown. It can be seen that the photoresponse current and response rate of the photoresponse continuous film device prepared in Application Example 1 are significantly higher than those of the other two devices.
[0115] Figure 13 To compare the photoresponse times of the three devices in Application Example 1 and Comparative Examples 1 and 2 under 1550 nm illumination, the results show that the rise time (τ) of PtS2, PtS, and PtS2 / PtS hybrid thin film devices is significantly longer. rise The decay times (τ) are 0.4s, 5.24s, and 3.0s, respectively. decayThe response times were 0.5s, 6.0s, and 5.0s, respectively, with the PtS2 device exhibiting the fastest response speed.
[0116] As can be seen from the application examples and comparative application examples, the two-dimensional atomically flat platinum disulfide thin film material provided in this application exhibits excellent photoelectric properties over a wide spectral range. Compared with PtS and PtS2 / PtS mixed films, it has the highest photocurrent and the fastest photoresponse time.
[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A two-dimensional, atomically flat platinum disulfide material, characterized in that, The platinum disulfide material has a two-dimensional planar spread structure, and its planar spread surface has atomic-level flatness. The thickness of the two-dimensional atomically flat platinum disulfide material is 2~31 nm; The platinum disulfide material can be at least 15 μm 2 The root mean square surface roughness is maintained at 0.26~0.67 nm within the specified range; The platinum disulfide material has a polycrystalline orientation structure characterized by a triple-symmetric pure 2H phase.
2. The two-dimensional atomically flat platinum disulfide thin film material as described in claim 1, characterized in that, The platinum disulfide material can be at least 26 cm 2 The root mean square surface roughness is maintained at 0.26~0.67 nm within the specified range.
3. A method for preparing a two-dimensional, atomically flat platinum disulfide material as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: (1) Provide a platinum thin film as a substrate, denoted as platinum substrate; (2) Platinum substrate is placed in an inert gas dispersion system of sulfur vapor, and the platinum substrate is heated in a programmed atmosphere of sulfur vapor to obtain a two-dimensional atomically flat platinum disulfide material. In the inert gas dispersion system of sulfur vapor, the volume concentration of sulfur vapor is 15~20 g / m³ at the termination temperature. 3 ; The starting temperature of the programmed temperature rise is 110~130℃, the ending temperature of the programmed temperature rise is 580~630℃, the heating rate is 2~4℃ / min, and the holding temperature at the ending temperature is 50~70 min.
4. The preparation method according to claim 3, characterized in that, The thickness of the platinum substrate is 1~6 nm.
5. The preparation method according to claim 3, characterized in that, The platinum substrate is obtained by magnetron sputtering or atomic layer deposition.
6. The preparation method according to claim 3, characterized in that, The step of placing the platinum substrate in an inert gas dispersion system of sulfur vapor includes: A reaction vessel is provided, in which a platinum substrate and a sulfur source are placed respectively. The reaction vessel is placed in an inert gas atmosphere and heated until the sulfur source vaporizes into sulfur vapor.
7. The preparation method according to claim 6, characterized in that, The inert gas atmosphere includes a gas path through which inert gas flows.
8. The preparation method according to claim 6, characterized in that, The reaction vessel includes either a quartz tube with a quartz plug or a quartz tube with a flow-limited opening.
9. The preparation method according to claim 6, characterized in that, The inert gas includes any one or a combination of at least two of argon and helium.
10. The preparation method according to any one of claims 3 to 9, characterized in that, The preparation method includes the following steps: (1) A platinum thin film is sputtered on the surface of a SiO2 / Si substrate by magnetron sputtering as a substrate, denoted as platinum substrate; (2) Place the platinum substrate in a tubular single-opening quartz container and place sulfur powder on the side of the platinum substrate near the opening; (3) Use a quartz plug to seal the opening of the quartz container, and place the quartz container in an inert atmosphere to grow a two-dimensional atomically flat platinum disulfide thin film material by heating from room temperature to the termination temperature at a rate of 2~4℃ / min.
11. The preparation method according to claim 10, characterized in that, The platinum substrate has an area of 0.5 × 0.5 cm. 2 ~2 square inches, the amount of sulfur powder added is 200~300mg.
12. The use of a two-dimensional, atomically flat platinum disulfide material as described in claim 1 or 2, characterized in that, The two-dimensional, atomically flat platinum disulfide material is used in any one of field-effect transistors and photodetectors.
13. The use as described in claim 12, characterized in that, The two-dimensional, atomically flat platinum disulfide material is used in any of the broadband photodetectors.
14. The use as described in claim 12, characterized in that, The two-dimensional atomically flat platinum disulfide material is used in any of the broadband photodetectors at room temperature.
15. A photoelectric-responsive continuous film device, characterized in that, The device includes: Substrate layer; The two-dimensional atomically flat platinum disulfide material as described in claim 1 or 2 is disposed on the substrate; An electrode layer is disposed on a two-dimensional, atomically flat platinum disulfide material.
16. The photoelectric-responsive continuous film device as described in claim 15, characterized in that, The substrate layer includes either a SiO2 / Si substrate or a sapphire substrate.
17. The photoelectric-responsive continuous film device as described in claim 15, characterized in that, The electrode layer includes a chromium layer close to the platinum disulfide material and a gold layer disposed on the side of the chromium layer away from the two-dimensional atomically flat platinum disulfide material.