A silicon-based PbSe single-crystal thin film, its preparation method, and an infrared photodetector

Abstract

The present invention belongs to the technical field of material growth, and specifically relates to a silicon-based PbSe single crystal thin film, a preparation method thereof, and an infrared photodetector, including a substrate, a graphene layer, and a PbSe thin film layer. The substrate is a silicon or silicon dioxide substrate; wherein, the surface roughness of the silicon-based PbSe single crystal thin film is 4 nm to 10 nm, the defect density is 0.8 nm-2 to 1.2 nm-2, and the full width at half maximum is 0.15° to 0.2°; the preparation method includes: transferring at least one layer of graphene onto the surface of a silicon substrate or a silicon dioxide substrate by a wet transfer process to form a graphene layer; epitaxially growing a PbSe thin film layer on the graphene layer by a chemical vapor deposition method. The beneficial effect of the present invention is that the present invention obtains a PbSe thin film with high quality, excellent single crystallinity, and flat surface on a functional substrate (silicon / silicon dioxide). At the same time, the excellent surface flatness is also more conducive to the application of the array process, and it is expected to realize the application of a large-area array of silicon-based PbSe.

Description

Technical Field

[0001] The present invention belongs to the technical field of material growth, and particularly relates to a silicon-based PbSe single crystal thin film, a preparation method thereof, and an infrared photodetector. Background Art

[0002] Lead salt thin films have been widely used in the fields of infrared detection, satellite sensing, and meteorological monitoring due to their high carrier mobility, strong light-matter interaction, and excellent optoelectronic conversion efficiency. Lead salt infrared detectors have a high detectivity in the 3-5μm atmospheric window at room temperature, and thus have excellent detection performance for short and medium-wave infrared light.

[0003] In recent years, due to the diversity of preparation processes and the increasing selectivity of substrate adaptation, lead salt semiconductors can be perfectly heteroepitaxially grown on other special substrates such as strontium titanate, mica, and ITO. This has enabled the discovery of the physical properties of high-quality single crystal lead salt thin films and the high-efficiency optoelectronic conversion characteristics brought by the infrared detectors prepared therefrom.

[0004] Due to the possibility of monolithic integration with silicon-based readout electronic devices, it has a broader prospect in the civilian market for mass production at low cost. However, due to the limitations of existing processes, the thin films of PbSe grown on silicon are basically polycrystalline thin films, and high-performance single crystal PbSe cannot be directly grown on silicon or silicon dioxide, which results in poor performance of PbSe on the most widely used functional substrates, silicon or silicon dioxide. Although polycrystalline nanometer thin films can be sensitized to be compatible with the silicon-based integration process and obtain good photoconductivity response signals, due to the problems of intrinsic carrier scattering and defects brought by polycrystalline thin films, the polycrystalline PbSe thin films on silicon always cannot reach the high performance level of other epitaxially grown thin films.

[0005] Therefore, how to grow single crystal PbSe on silicon or silicon dioxide and obtain good performance is a technical problem that needs to be solved urgently. Summary of the Invention

[0006] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and provide a silicon-based PbSe single crystal thin film, a preparation method thereof, and an infrared photodetector.

[0007] The technical solution of the present invention is as follows:

[0008] The first aspect of the present invention provides a silicon-based PbSe single crystal thin film, including a substrate, a graphene layer disposed on the substrate, and a PbSe thin film layer disposed on the graphene layer, wherein the substrate is a silicon substrate or a silicon dioxide substrate;

[0009] Among them, the surface roughness of the silicon-based PbSe single-crystal thin film is 4 nm to 10 nm;

[0010] The defect density of the silicon-based PbSe single-crystal thin film is 0.8 nm -2 ~1.2 nm -2 ;

[0011] The full width at half maximum of the silicon-based PbSe single-crystal thin film is 0.15° to 0.2°.

[0012] Optionally, the silicon-based PbSe single-crystal thin film has a (200) crystal plane orientation.

[0013] Optionally, the thickness of the graphene layer is 0.3 nm to 1.2 nm.

[0014] Optionally, the thickness of the graphene layer is 0.3 nm to 0.4 nm.

[0015] Optionally, the thickness of the PbSe thin film layer is 80 nm to 100 nm.

[0016] Optionally, the silicon crystal plane of the substrate is the (100) plane.

[0017] The second aspect of the present invention provides a preparation method for self-assembled growth of a PbSe single-crystal thin film on a silicon / silicon dioxide substrate, including the following steps:

[0018] Adopt a wet transfer process to transfer at least one layer of graphene onto the surface of a silicon substrate or a silicon dioxide substrate, form a graphene layer on the surface of the silicon substrate or the silicon dioxide substrate, and obtain a silicon substrate or a silicon dioxide substrate with a graphene layer;

[0019] Adopt chemical vapor deposition to epitaxially grow PbSe on the graphene layer to form a PbSe thin film layer, and obtain a silicon-based PbSe single-crystal thin film.

[0020] Optionally, the method of adopting a wet transfer process to transfer at least one layer of graphene onto the surface of a silicon substrate or a silicon dioxide substrate specifically includes the following steps:

[0021] Coat PMMA (polymethyl methacrylate) on the surface of the single-layer or multi-layer graphene grown on the copper foil, dry it, and then soak it in a KOH solution until the PMMA floats up;

[0022] Use a silicon substrate or a silicon dioxide substrate to pick up the floating PMMA, rinse it with water and dry it, and finally soak it in an acetone solution, rinse it with water and blow it dry, form a graphene layer on the surface of the silicon substrate or the silicon dioxide substrate, and obtain a silicon substrate or a silicon dioxide substrate with a graphene layer.

[0023] Optionally, the mass fraction of the KOH solution is 15% - 25%, and the immersion time in the acetone solution is 1h - 2h.

[0024] Optionally, the method for epitaxial growth of PbSe on the graphene layer specifically includes the following steps:

[0025] Along the flow direction of the carrier gas from upstream to downstream, using PbSe powder as the evaporation source material and Se powder as the supplementary source, setting the silicon substrate or silicon dioxide substrate with the graphene layer, evacuating, first heating, then maintaining the temperature, and finally cooling to form a PbSe thin film layer;

[0026] The heating temperatures of the Se powder and PbSe powder are 250°C - 350°C and 700°C - 750°C respectively, the heating rate ≤ 10°C / min, and the time from room temperature to the heating temperature is 70min - 80min;

[0027] The heating temperature of the silicon substrate or silicon dioxide substrate with the graphene layer is 300°C - 400°C;

[0028] The heat preservation time is 4min - 8min;

[0029] The evacuation is carried out to a vacuum degree of 1×10 -3 Pa - 1×10 -2 Pa, and the carrier gas flow rate is controlled at 10sccm - 20sccm;

[0030] The PbSe powder and Se powder are mixed in a mass ratio of 1 - 2:2 - 4.

[0031] The third aspect of the present invention provides an infrared photodetector, including the above-mentioned silicon-based PbSe single crystal thin film.

[0032] Through testing, it is found that the PbSe device on the silicon substrate can still achieve a microamp-level photoelectric response under the condition of a micro-watt-level optical power, demonstrating its reliability in the field of infrared photodetection.

[0033] The present invention has at least one of the following beneficial effects:

[0034] In the present invention, a graphene layer is first formed on the surface of the silicon / silicon dioxide substrate through a wet transfer process, and then the silicon / silicon dioxide substrate with the graphene layer is used to grow a PbSe thin film by chemical vapor deposition. By controlling the growth parameters, a PbSe thin film with a flat surface, high thickness uniformity, and obvious single crystal diffraction peaks is obtained.

[0035] The present invention first forms a graphene layer on the surface of a silicon / silicon dioxide substrate, and then grows a PbSe thin film on the graphene layer, obtaining a PbSe thin film with high quality, excellent single crystal properties, and a flat surface on a functional substrate (silicon / silicon dioxide), solving the problem in the prior art that it is impossible to directly grow single crystal PbSe with good performance on a silicon or silicon dioxide substrate. Compared with directly growing single crystal PbSe on a silicon or silicon dioxide substrate in the prior art, the silicon-based PbSe single crystal thin film prepared by the present invention not only has the advantages of low roughness, high density, and excellent single crystal properties, but also the excellent surface flatness is more conducive to the application of array processes, and it is expected to realize the commercial application of large-area arrays of silicon-based PbSe. Description of the Drawings

[0036] Figure 1 It is a schematic flow chart of transferring graphene and growing PbSe on the silicon / silicon dioxide surface in Examples 1 to 2 of the invention.

[0037] Figure 2 It is a scanning electron microscope surface morphology diagram of growing PbSe with single-layer graphene in Example 1 of the present invention and growing PbSe without graphene in Comparative Example 1; among them, a is the scanning electron microscope surface morphology diagram of growing PbSe with single-layer graphene in Example 1, and b is the scanning electron microscope surface morphology diagram of growing PbSe without graphene in Comparative Example 1.

[0038] Figure 3 It is a surface roughness characterization diagram of growing PbSe with single-layer graphene in Example 1 of the present invention and growing PbSe without graphene in Comparative Example 1; among them, a is the surface roughness characterization diagram of growing PbSe with single-layer graphene in Example 1, and b is the surface roughness characterization diagram of growing PbSe without graphene in Comparative Example 1.

[0039] Figure 4 It is a transmission electron microscope characterization diagram of growing PbSe with single-layer graphene in Example 1 of the present invention and growing PbSe without graphene in Comparative Example 1; among them, a is the transmission electron microscope characterization diagram of growing PbSe with single-layer graphene in Example 1, and b is the transmission electron microscope characterization diagram of growing PbSe without graphene in Comparative Example 1.

[0040] Figure 5 It is an x-ray diffraction pattern of growing PbSe with single-layer graphene in Example 1 of the present invention and growing PbSe without graphene in Comparative Example 1.

[0041] Figure 6 It is the mid-wave infrared detection performance characterization of growing PbSe with single-layer graphene in Example 1 of the present invention.

[0042] Figure 7 It is a scanning electron microscope surface morphology diagram of growing PbSe with double-layer graphene in Example 2 of the present invention.

[0043] Figure 8 This is the X-ray diffraction pattern of the double-layer graphene-grown PbSe in Example 2 of the present invention. Detailed implementation manners

[0044] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to 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.

[0045] An embodiment of the present invention provides a silicon-based PbSe single crystal thin film, which mainly includes: silicon / silicon dioxide with a growth crystal plane of (100) as the substrate, at least one layer of graphene transferred on the surface of the silicon / silicon dioxide, and a PbSe thin film layer epitaxially grown on the graphene:

[0046] In some embodiments, the substrate is silicon / silicon dioxide with a growth crystal plane of (100), and the thickness of the oxide layer on the surface of the silicon / silicon dioxide substrate used is preferably 200 nm to 400 nm, and more preferably 300 nm.

[0047] In some embodiments, the thickness of the single-layer graphene thin film layer is 0.3 nm to 0.4 nm.

[0048] In some embodiments, 1 to 3 layers of graphene are transferred on the surface of the silicon / silicon dioxide.

[0049] Another embodiment of the present invention provides a preparation method for self-assembled growth of a PbSe single crystal thin film on a silicon / silicon dioxide substrate, including the following steps:

[0050] Transferring graphene to the silicon / silicon dioxide substrate: Using a wet transfer process to transfer at least one layer of graphene onto the surface of the silicon substrate or the silicon dioxide substrate to form a graphene layer on the surface of the silicon substrate or the silicon dioxide substrate;

[0051] Growing the PbSe thin film: Using chemical vapor deposition to epitaxially grow PbSe on the graphene layer to form a PbSe thin film layer, and obtaining a silicon-based PbSe single crystal thin film.

[0052] In some embodiments, the methods for transferring the graphene to the silicon / silicon dioxide substrate mainly include:

[0053] Uniformly coat a layer of PMMA on the surface of single-layer or multi-layer graphene grown on a copper foil, and use a heating stage to heat it to 100 °C and keep it for 20 min to 30 min to dry the PMMA; take KOH powder and deionized water and prepare a KOH solution with a mass fraction of 15% to 25% according to a mass ratio of 1:4 to 6; soak the PMMA until it floats on top of the KOH solution, and the PMMA will carry the single-layer or multi-layer graphene film and float on the surface of the KOH solution.

[0054] Pick up the PMMA with a clean silicon / silicon dioxide substrate, rinse it with deionized water and then dry it on a heating stage at 60 °C; soak the silicon / silicon dioxide substrate with PMMA in an acetone solution for 1 h to 2 h, rinse it with water and blow it dry to obtain a silicon / silicon dioxide substrate transferred with single-layer graphene.

[0055] In some embodiments, growing a PbSe film on a silicon / silicon dioxide substrate transferred with single-layer graphene includes the following steps:

[0056] Use chemical vapor deposition with PbSe and Se powder as raw materials to grow on the surface of the silicon / silicon dioxide substrate of the single-layer graphene film; the chemical vapor deposition includes a heating stage, a deposition stage and a cooling stage; the flow rate of the carrier gas during the chemical vapor deposition process is preferably 10 sccm.

[0057] In some embodiments, the chemical vapor deposition includes the following steps: along the flow direction of the carrier gas from upstream to downstream, sequentially arrange a Se powder evaporation source, a PbSe powder evaporation source and a silicon / silicon dioxide substrate with a graphene film; the heating temperature of the Se powder evaporation source is 300 °C, the heating temperature of the PbSe powder evaporation source is 750 °C, and the heating temperature of the silicon substrate or silicon dioxide substrate is 300 °C to 400 °C; the heating rate of the mixed powder in the heating stage is ≤10 °C / min.

[0058] In some embodiments, the holding time in the deposition stage is 4 min to 8 min; the deposition thickness of the PbSe single crystal film layer is 80 nm to 100 nm.

[0059] In some embodiments, the raw material powder used for growing the PbSe film is preferably a mixed powder prepared by mixing PbSe powder and Se powder according to a mass ratio of 1:2.

[0060] In some embodiments, the thickness of the PbSe film grown on the silicon substrate or silicon dioxide surface is preferably 80 nm.

[0061] In some embodiments, the surface of the PbSe grown using the silicon / silicon dioxide substrate transferred with graphene is flatter and the crystal orientation is more consistent from the scanning electron microscope image.

[0062] In some embodiments, the surface roughness of PbSe grown on a silicon / silicon dioxide substrate transferred with graphene is lower as measured by a profilometer within the same scanning range.

[0063] In some embodiments, the crystal quality of the grown PbSe thin film can be clearly judged by the position of the XRD diffraction peak, and differences in peak position and size can be found between PbSe grown on a silicon / silicon dioxide substrate transferred with graphene and PbSe directly grown on silicon / silicon dioxide.

[0064] In some embodiments, the method of self-assembled growth of PbSe single crystal thin film by transferring graphene on a silicon / silicon dioxide substrate has excellent optoelectronic detection characteristics. The characterization means used include X-ray diffraction spectra, scanning electron microscope morphology images, and various electrical test source meters.

[0065] The following specific embodiments are used to further illustrate the present invention in detail, but the present invention is not limited to the following specific embodiments.

[0066] Example 1

[0067] This example provides a preparation method for self-assembled growth of PbSe single crystal thin film by transferring graphene on a silicon dioxide substrate. The process flow is as Figure 1 shown, and specifically includes the following steps:

[0068] (1) Transfer monolayer graphene.

[0069] Purchase monolayer graphene on copper foil, uniformly coat a layer of PMMA (polymethyl methacrylate) on its surface. The rotating table can be used to set the rotation speed to 600 r / min and rotate for 1 min to make it more uniform. Then place the copper foil spin-coated with PMMA on a heating table, and set the temperature of the heating table to 100 °C and keep it for 30 min to cure the PMMA.

[0070] Take KOH powder and deionized water and prepare a 20% KOH solution with a mass ratio of 1:5. Immerse the copper foil with PMMA in the KOH solution. After 2 h, the PMMA will carry the monolayer graphene film and float on the surface of the KOH solution.

[0071] Pick up a clean silicon dioxide substrate to pick up the PMMA, and the PMMA will carry the monolayer graphene film and attach to the silicon substrate; rinse with deionized water and dry it on a heating table at 60 °C. Then immerse the silicon dioxide substrate with PMMA in acetone solution for 1 h, rinse and blow dry to form a graphene / silicon substrate, that is, a silicon dioxide substrate transferred with monolayer graphene is obtained.

[0072] (2) Grow the PbSe thin film.

[0073] Along the flow direction of the carrier gas from upstream to downstream, 0.2 g of PbSe (99.99%) is placed at the center of a 12-inch horizontal tube furnace as the evaporation source material, and 0.4 g of selenium powder is placed at the front of the furnace as the supplementary source; the silica substrate transferred with monolayer graphene is set 10 cm away from the outlet at the end of the furnace. After sealing the tube furnace, it is evacuated to a vacuum degree of 1×10 -3 Pa by a mechanical pump and a molecular pump, and the carrier gas flow rate is controlled at 10 sccm. The heating temperature of the selenium powder supplementary source is 300 °C, the heating temperature of the PbSe powder is set at 750 °C, and the temperature of the silica substrate transferred with monolayer graphene is set at 450 °C; the time for the tube furnace to heat up from room temperature to the heating temperature of the PbSe powder (750 °C) is 75 min. After the steam formed by the reaction source and the selenium powder supplementary source is transported by the carrier gas to the surface of the silica substrate transferred with monolayer graphene for reaction for 6 min, the heating power supply of the tube furnace is cut off, and the furnace body is naturally cooled to room temperature to obtain a single-crystal PbSe thin film.

[0074] By this method, a PbSe thin film can be successfully grown on the silica substrate, solving the problem that a PbSe single-crystal thin film with good performance cannot be obtained on a silicon or silica substrate in the prior art.

[0075] Comparative Example 1

[0076] The difference from Example 1 is only that: step (1) is not carried out, and a PbSe thin film is directly grown on the surface of the silica substrate according to the method of step (2).

[0077] The performance of the PbSe thin film transferred with monolayer graphene prepared in Example 1 and the PbSe thin film prepared in Comparative Example 1 was tested, and the test results are as follows:

[0078] The scanning electron microscope results of the PbSe thin film transferred with monolayer graphene prepared in Example 1 and the PbSe thin film prepared in Comparative Example 1 are as Figure 2 shown. It can be seen from the figure that the surface of the PbSe thin film grown after transferring monolayer graphene on the silica surface prepared in Example 1 ( Figure 2 a in) is significantly denser than that of the PbSe thin film grown directly on the silica substrate prepared in Comparative Example 1 ( Figure 2 b in). This shows that by first forming a graphene layer on a silicon or silica substrate and then growing a PbSe thin film on the graphene layer, it helps to make the PbSe growth orientation consistent and at the same time ensures that the requirements for light detection of a single-crystal thin film can be met.

[0079] Figure 3Surface roughness characterization of the PbSe film with monolayer graphene transferred prepared in Example 1 and the PbSe film prepared in Comparative Example 1. From the data in the figure, it can be known that the surface roughness of PbSe grown on the silica substrate with transferred graphene is about 5.87 nm ( Figure 3 in a), while the surface roughness of PbSe directly grown on the silicon dioxide surface is about 36.58 nm ( Figure 3 in b). This shows that by first forming a graphene layer on the silicon or silica substrate and then growing the PbSe film on the graphene layer, it helps to reduce the surface roughness of PbSe.

[0080] Figure 4 Selected area electron diffraction characterization of the PbSe film with monolayer graphene transferred prepared in Example 1 ( Figure 4 in a) and the PbSe film prepared in Comparative Example 1 ( Figure 4 in b). It can be observed from the figure that compared with the PbSe directly grown on the silica substrate where no regular sites can be found, obvious (200) crystal plane sites can be found for the PbSe grown on the transferred graphene silicon dioxide, confirming the crystal orientation of PbSe growth in the region.

[0081] Figure 5 X-ray diffraction patterns of the PbSe film with monolayer graphene transferred prepared in Example 1 and the PbSe film prepared in Comparative Example 1. From the full width at half maximum of 0.176°, it can be judged that the crystal quality of PbSe grown on the silica substrate with transferred graphene is much higher than that of PbSe directly grown on silica. Thus, it can be seen that the single crystal quality of the entire PbSe film has reached a relatively high level.

[0082] Figure 6 Characterization of the mid-wave infrared detection performance of the PbSe film with monolayer graphene transferred prepared in Example 1. From the characterization results, it can be seen that the PbSe device on the silicon substrate can still achieve a microampere-level photoelectric response under the condition of a micro-watt-level optical power, demonstrating its reliability in the field of infrared photoelectric detection.

[0083] Example 2

[0084] This example provides a preparation method for self-assembled growth of PbSe single crystal films by transferring bilayer graphene on a silicon substrate, which specifically includes the following steps:

[0085] (1) Transfer bilayer graphene.

[0086] Prepare a double-layer graphene on a purchased copper foil, and uniformly coat a layer of PMMA (polymethyl methacrylate) on its surface. You can use a turntable to set the rotation speed at 600 r / min and rotate for 1 min to make it more uniform. Then place the copper foil coated with PMMA on a heating table, and set the temperature of the heating table to be maintained at 100 °C for 30 min to cure the PMMA.

[0087] Take KOH powder and deionized water and prepare a 20% KOH solution with a mass ratio of 1:5. Immerse the copper foil with PMMA in the KOH solution. After 2 h, the PMMA will carry a single-layer graphene film and float on the surface of the KOH solution.

[0088] Pick up a clean silica substrate to pick up the PMMA, and the PMMA will carry a single-layer graphene film and adhere to the silica substrate; rinse it with deionized water and dry it on a heating table at 60 °C. Then immerse the silica substrate with PMMA in an acetone solution for 2 h, rinse and blow dry to form a graphene / silica substrate, that is, obtain a silica substrate with double-layer graphene transferred.

[0089] (2) Grow a PbSe film.

[0090] The specific steps are the same as those in Example 1.

[0091] For the PbSe film with transferred double-layer graphene prepared in Example 2, the test results are as follows:

[0092] As Figure 7 shown is the PbSe film with transferred double-layer graphene. It can be seen from the figure that the surface density of the PbSe film grown after transferring double-layer graphene on the silica surface prepared in Example 2 is comparable to that of the PbSe film grown on the single-layer graphene prepared in Example 1. Figure 8 The x-ray diffraction pattern of the PbSe film with transferred double-layer graphene prepared in Example 2 has a full width at half maximum of about 0.181°. It can be judged that the quality of the PbSe crystal grown on the silica substrate with transferred double-layer graphene is still reliable, indicating that this method is also applicable to the silicon substrate with transferred double-layer graphene.

[0093] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A preparation method of a silicon-based PbSe single crystal thin film, characterized in that, The preparation method includes the following steps: Coat the surface of monolayer or multilayer graphene grown on a copper foil with polymethyl methacrylate, dry it, and then soak it in a KOH solution until the polymethyl methacrylate floats up; Use a silicon substrate or a silicon dioxide substrate to pick up the floating polymethyl methacrylate, rinse it with water and then dry it, and finally soak it in an acetone solution, rinse it with water and blow it dry to form a graphene layer on the surface of the silicon substrate or the silicon dioxide substrate, obtaining a silicon substrate or a silicon dioxide substrate with a graphene layer; Epitaxially grow PbSe on the graphene layer by chemical vapor deposition to form a PbSe thin film layer, obtaining a silicon-based PbSe single crystal thin film; The silicon-based PbSe single crystal thin film obtained by the preparation method includes a substrate, a graphene layer disposed on the substrate, and a PbSe thin film layer disposed on the graphene layer, and the substrate is a silicon substrate or a silicon dioxide substrate; Among them, the surface roughness of the silicon-based PbSe single crystal thin film is 4 nm to 10 nm; The defect density of the silicon-based PbSe single-crystal thin film is 0.8 nm -2 ~1.2 nm -2 ; The full width at half maximum of the silicon-based PbSe single crystal thin film is 0.15° to 0.2°; The silicon-based PbSe single crystal thin film has a (200) crystal plane orientation; The thickness of the graphene layer is 0.3 nm to 1.2 nm; The thickness of the PbSe thin film layer is 80 nm to 100 nm; The silicon crystal plane of the substrate is the (100) plane.

2. The preparation method according to claim 1, characterized in that, The mass fraction of the KOH solution is 15% to 25%, and the soaking time in the acetone solution is 1 h to 2 h.

3. The preparation method according to claim 1, characterized in that, The method for epitaxially growing PbSe on the graphene layer specifically includes the following steps: Along the flow direction of the carrier gas from upstream to downstream, using PbSe powder as the evaporation source material and Se powder as the supplementary source, set a silicon substrate or a silicon dioxide substrate with a graphene layer, evacuate, first heat up, then keep warm, and finally cool down to form a PbSe thin film layer; The heating temperatures of the Se powder and the PbSe powder are 250°C to 350°C and 700°C to 750°C respectively, the heating rate ≤ 10°C / min, and the time from room temperature to the heating temperature is 70 min to 80 min; The heating temperature of the silicon substrate or the silicon dioxide substrate with a graphene layer is 300°C to 400°C; The heat preservation time is 4 min to 8 min; The vacuum is pumped to a vacuum degree of 1×10 -3 Pa to 1×10 -2 Pa, and the carrier gas flow rate is controlled to be 10 sccm to 20 sccm; The PbSe powder and the Se powder are mixed according to a mass ratio of 1 to 2:2 to 4.

4. An infrared photodetector, characterized in that, A silicon-based PbSe single crystal thin film obtained by the preparation method according to any one of claims 1 to 3.

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