Photoelectric detector based on slow light effect

Abstract

The invention is suitable for the technical field of integrated optics, and provides a photoelectric detector based on a slow light effect, and the detector comprises a silicon substrate; the buried oxide layer is formed at the top of the silicon substrate, a Mie waveguide is arranged at the top of the buried oxide layer, and rectangular waveguides are arranged at the two ends of the Mie waveguide; the isolation layer is formed on the top of the buried oxide layer, and the Mie waveguide and the rectangular waveguide are both located in the isolation layer; the two-dimensional material layer is formed on the top of the isolation layer, a first metal electrode, a second metal electrode and a gold nano-strip are arranged on the top of the two-dimensional material layer, and the gold nano-strip is located between the first metal electrode and the second metal electrode. The performance of the photoelectric detector can be improved, and the increasing precision measurement requirement can be met.

Description

Technical Field

[0001] The present application belongs to the field of integrated optical technology, and in particular, relates to a photoelectric detector based on the slow light effect. Background Art

[0002] The past few decades have witnessed a growing interest in the development of on-chip nonlinear optical devices due to their enormous applications, such as quantum photonics, all-optical communications, optical computing, on-chip metrology and sensing. Developing efficient on-chip nonlinear optical devices to meet the requirements of these applications requires new directions to improve existing photonic approaches. Recent research has led the field of on-chip nonlinear optics toward the hybrid integration of two-dimensional layered materials (e.g., graphene, transition metal chalcogenides, and black phosphorus) with various integration platforms. The combination of well-known photonic chip design platforms (e.g., silicon, silicon nitride) with different two-dimensional layered materials opens the way to more versatile and efficient structures and devices, with great potential to unlock many new possibilities.

[0003] Two-dimensional materials are atomically thin layers of materials that are stacked together by weak van der Waals forces, such as graphene, black phosphorus (BP), tellurium (Te), and palladium selenide (PdSe). 2 ) etc. Two-dimensional (2D) materials have the following advantages: relatively simple manufacturing process, high-quality surface without dangling bonds, strong light-matter interaction per unit volume, simple heterojunction structure and compatibility with complementary metal oxide semiconductor (CMOS) devices. Therefore, people are committed to the fabrication of infrared photodetectors based on 2D materials, exploring novelties in structure and materials to improve the performance of infrared photodetection.

[0004] Various designs of infrared photodetectors based on two-dimensional materials have been verified. Although experiments have shown that infrared photodetectors based on two-dimensional materials can exhibit fast response speed, wide infrared spectral response and low dark current, due to the atomic layer thickness of two-dimensional materials, light absorption in these ultra-thin materials is limited, and their light response is usually low. In recent years, researchers have achieved the combination of two-dimensional materials and optical waveguides, and the performance of photodetectors has improved to a certain extent. However, due to the structure of the photodetector, its performance is poor and cannot meet the growing demand for precision measurement. Summary of the invention

[0005] The embodiments of the present application provide a photoelectric detector based on the slow light effect, which can solve the problem that the performance of the photoelectric detector is poor and cannot meet the growing demand for precision measurement.

[0006] The present application embodiment provides a photoelectric detector based on the slow light effect, including:

[0007] Silicon substrate;

[0008] A buried oxide layer is formed on the top of the silicon substrate, a Mie waveguide is arranged on the top of the buried oxide layer, and rectangular waveguides are arranged at both ends of the Mie waveguide;

[0009] An isolation layer is formed on the top of the buried oxide layer, and the Mie waveguide and the rectangular waveguide are both located in the isolation layer;

[0010] A two-dimensional material layer is formed on the top of the isolation layer. A first metal electrode, a second metal electrode and a gold nanorod are arranged on the top of the two-dimensional material layer. The gold nanorod is located between the first metal electrode and the second metal electrode.

[0011] Optionally, the Mie waveguide is made of cylindrical nanochains.

[0012] Optionally, the diameter of a cylinder in the cylindrical nanochain is 300 nm to 340 nm, and the distance between two adjacent cylinders in the cylindrical nanochain is 130 nm to 170 nm.

[0013] Optionally, the thickness of the Mie waveguide and the rectangular waveguide are both 150nm to 220nm, and the width of the rectangular waveguide is 300nm to 340nm.

[0014] Optionally, the material of the Mie waveguide is one of silicon, germanium, a silicon-germanium mixture and silicon nitride.

[0015] Optionally, the width of the gold nanostrip is 150 nm to 200 nm, the height is 100 nm to 200 nm, and the length of the gold nanostrip is equal to the sum of the length of the Mie waveguide and the length of the two rectangular waveguides.

[0016] Optionally, the thickness of the silicon substrate is 700 μm to 900 μm.

[0017] Optionally, the buried oxide layer has a thickness of 2 μm to 3 μm.

[0018] Optionally, the thickness of the isolation layer is 10 nm to 100 nm, and the material of the isolation layer is silicon dioxide, Al 2 O 3 Or hexagonal boron nitride.

[0019] Optionally, the thickness of the two-dimensional material layer is 30 nm to 150 nm, the two-dimensional material layer is a two-dimensional material layer composed of one two-dimensional material, or a heterojunction formed by combining two two-dimensional materials, and the two-dimensional material is palladium selenide, MoTe 2 , PtSe 2 .

[0020] The above solution of the present application has the following beneficial effects:

[0021] In an embodiment of the present application, the waveguide of the photodetector is composed of a Mie waveguide and a rectangular waveguide located at both ends thereof. The light propagating in the Mie waveguide interacts with the two-dimensional material layer through the evanescent field. Compared with the traditional method of heterogeneously integrating two-dimensional materials in a rectangular waveguide, the Mie waveguide has a slow light effect in the communication band, which will enhance the interaction between light and matter inside and around the Mie waveguide. At the same time, the gold nanostrips arranged on the top of the two-dimensional material layer can further enhance the electric field, achieve high responsiveness and wide spectrum performance in the communication range, and thus improve the performance of the photodetector.

[0022] Other beneficial effects of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic cross-sectional view of a photodetector provided in one embodiment of the present application;

[0025] Figure 2 A top view of a photodetector provided in one embodiment of the present application;

[0026] Figure 3 A schematic diagram of the structure of a cylinder in a Mie waveguide provided in an embodiment of the present application;

[0027] Figure 4 The Mie waveguide transmittance varies with the incident wavelength;

[0028] Figure 5 is a curve diagram of electric field intensity and transmittance varying with the width of the metal strip;

[0029] Figure 6 It is the curve diagram of electric field intensity and transmittance changing with the height of metal strip;

[0030] Figure 7 PdSe based on rectangular waveguide 2 Current-voltage (IV) curves of the photodetector in the dark and under illumination with different light powers at 1550nm;

[0031] Figure 8 PdSe based on Mie waveguide 2 Current-voltage (IV) curves of the photodetector in the dark and under illumination with different light powers at 1550nm;

[0032] Fig. 9 PdSe based gold nanorods for enhanced Mie waveguides 2 Current-voltage (IV) curves of the photodetector in the dark and under illumination with different light powers at 1550nm;

[0033] Fig.10 PdSe based gold nanorods for enhanced Mie waveguides 2 Graphs of the photocurrent and photoresponsivity of a photodetector versus incident power;

[0034] Fig.11 PdSe based gold nanorods for enhanced Mie waveguides 2 Plots of the photocurrent and waveguide transmittance of the photodetector versus the thickness of the isolation layer;

[0035] Fig.12 The loss of Mie waveguide and PdSe 2 Layer thickness relationship graph;

[0036] Fig.13 PdSe based gold nanorods for enhanced Mie waveguides 2 Photodetector photocurrent and Mie waveguide transmittance vs. PdSe 2 Layer thickness relationship graph;

[0037] Fig.14 PdSe based gold nanorods for enhanced Mie waveguides 2 The light absorption rate of the photodetector increases with the PdSe 2 Layer length variation curve.

[0038] [Description of Reference Numerals]

[0039] 1. Silicon substrate; 2. Buried oxide layer; 3. Mie waveguide; 4. Rectangular waveguide; 5. Isolation layer; 6. Two-dimensional material layer; 7. Gold nanostrips; 8. First metal electrode; 9. Second metal electrode. DETAILED DESCRIPTION

[0040] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0041] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0042] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0043] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0044] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0045] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0046] In response to the problem of poor performance of current photodetectors, an embodiment of the present application provides a photodetector based on the slow light effect. The waveguide of the photodetector is composed of a Mie waveguide and a rectangular waveguide located at both ends thereof. The light propagating in the Mie waveguide interacts with the two-dimensional material layer through the evanescent field. Compared with the traditional method of heterogeneously integrating two-dimensional materials in a rectangular waveguide, the Mie waveguide has a slow light effect in the communication band, which will enhance the interaction between light and matter inside and around the Mie waveguide. At the same time, the electric field is further enhanced by using gold nanostrips arranged on the top of the two-dimensional material layer, thereby achieving high responsiveness and wide spectrum performance in the communication range, thereby improving the performance of the photodetector.

[0047] The photoelectric detector based on the slow light effect provided in the embodiment of the present application is exemplarily described below in conjunction with specific embodiments.

[0048] like Figure 1 to Figure 2 As shown, the photodetector based on the slow light effect provided in the embodiment of the present application includes: a silicon substrate 1; a buried oxide layer 2 formed on the top of the silicon substrate 1, a Mie waveguide 3 is provided on the top of the buried oxide layer 2, and rectangular waveguides 4 are provided at both ends of the Mie waveguide 3; an isolation layer 5 formed on the top of the buried oxide layer 2, and the Mie waveguide 3 and the rectangular waveguide 4 are both located in the isolation layer 5; a two-dimensional material layer 6 is formed on the top of the isolation layer 5, a first metal electrode 8, a second metal electrode 9 and a gold nanorod 7 are provided on the top of the two-dimensional material layer 6, the gold nanorod 7 is located between the first metal electrode 8 and the second metal electrode 9, and the first metal electrode 8, the second metal electrode 9 and the two-dimensional material layer 6 are connected to form a conductive path.

[0049] Among them, Mie waveguide 3 is a waveguide structure designed using Mie scattering theory, which realizes the confinement and guidance of electromagnetic waves by integrating waveguides with specific functional subwavelength structures. Specifically, the above-mentioned Mie waveguide 3 is made of cylindrical nanochains, and the Mie waveguide 3 propagates in the TE polarization fundamental mode. The diameter and spacing of the cylinders in the Mie waveguide 3 will affect the propagation of the incident light. By adjusting the diameter and spacing of the nanochain, the photonic band gap position can be changed, thereby improving the performance of the photodetector.

[0050] In some embodiments of the present application, in order to improve the performance of the photodetector, such as Figure 3 As shown, the diameter of the cylinder in the cylindrical nanochain is 300nm to 340nm, and the spacing g between two adjacent cylinders in the cylindrical nanochain is 130nm to 170nm, so as to meet the transmission of communication band light. The thickness of Mie waveguide 3 and rectangular waveguide 4 are both 150nm to 220nm, and the width of rectangular waveguide 4 is 300nm to 340nm. Rectangular waveguide 4 is mainly used to couple incident light into Mie waveguide 3. The material of Mie waveguide 3 is one of silicon, germanium, silicon germanium mixture and silicon nitride.

[0051] In some embodiments of the present application, the width of the gold nanorod 7 is 150 nm to 200 nm, the height is 100 nm to 200 nm, and the length of the gold nanorod 7 is equal to the sum of the length of the Mie waveguide 3 and the length of the two rectangular waveguides 4 .

[0052] In some embodiments of the present application, the thickness of the silicon substrate 1 is 700 μm to 900 μm, the thickness of the buried oxide layer 2 is 2 μm to 3 μm, the thickness of the isolation layer 5 is 10 nm to 100 nm, and the material of the isolation layer 5 is silicon dioxide, Al 2 O 3Or hexagonal boron nitride. The thickness of the two-dimensional material layer 6 is 30nm to 150nm. The two-dimensional material layer 6 is a two-dimensional material layer composed of one two-dimensional material, or a heterojunction formed by combining two two-dimensional materials. The two-dimensional material is palladium selenide, MoTe 2 , PtSe 2 wait.

[0053] It can be understood that in the embodiments of the present application, the shapes, materials and sizes of the silicon substrate 1, buried oxide layer 2, rectangular waveguide 4, Mie waveguide 3, isolation layer 5, two-dimensional material layer 6 and gold nanorods 7 are not limited and can be adjusted according to actual conditions.

[0054] It should be noted that the two-dimensional material layer 6 is located between the gold nanorods 7 and the Mie waveguide 3. The light propagating in the Mie waveguide 3 interacts with the two-dimensional material layer 6 through evanescent field coupling. The Mie waveguide 3 will produce a slow light effect near the communication band, enhancing the interaction between light and matter inside and around the Mie waveguide 3. At the same time, since the Mie waveguide 3 is surrounded by the isolation layer 5, the interaction between light and matter inside and around the Mie waveguide 3 can be enhanced to the maximum extent.

[0055] It should be further explained that when the electric field is not enhanced, the electric field distribution of the Mie waveguide 3 is mainly concentrated in the middle and both sides of the waveguide. By setting the gold nanorods 7 to enhance the electric field, the electric field distribution of the Mie waveguide 3 is mainly concentrated at the interface between the gold nanorods 7 and the Mie waveguide 3, and the electric field strength is increased by two times compared with the Mie waveguide 3 structure. The interface is the position of the two-dimensional material layer 6. Therefore, the gold nanorods 7 to enhance the Mie waveguide 3 structure can enhance the interface electric field, further improve the light absorption of the two-dimensional material, and enhance the light response.

[0056] Specifically, the electric field strength can be adjusted by adjusting the width of the gold nanorod 7, and the transmittance can be adjusted by changing the height of the gold nanorod 7; the isolation layer 5 can prevent the transfer of photogenerated carriers between the two-dimensional material layer 6 and the Mie waveguide 3; the transmittance and surface electric field strength of the Mie waveguide 3 can be adjusted by adjusting the thickness of the isolation layer 5; the influence of the two-dimensional material layer 6 on the loss, transmittance and photocurrent of the waveguide can be adjusted by adjusting the thickness of the two-dimensional material layer 6 covering the gold nanorod 7 to enhance the Mie waveguide 3; the absorption rate of the two-dimensional material layer 6 to the incident light can be adjusted by adjusting the length of the two-dimensional material layer 6 covering the gold nanorod 7 to enhance the Mie waveguide 3. It should be noted that the role and structure of the silicon substrate 1 and the buried oxide layer 2 in the above-mentioned photodetector are the same as those of the traditional photodetector, the silicon substrate 1 is mainly used to provide support and foundation, and the buried oxide layer 2 is mainly used to improve electrical insulation and overall performance.

[0057] The above-mentioned electrode pair (i.e., the first metal electrode 8 and the second metal electrode 9) is used to apply a bias voltage and measure current. When the rectangular waveguide 4 at both ends of the Mie waveguide 3 couples the incident light into the Mie waveguide 3, and the incident light propagates in the Mie waveguide 3, the light propagating in the Mie waveguide 3 interacts with the two-dimensional material layer 6 through evanescent field coupling. By applying a bias voltage at both ends of the two-dimensional material layer 6 (i.e., the first metal electrode 8 and the second metal electrode 9), a photocurrent can be obtained; when there is no incident light, by applying a bias voltage at both ends of the two-dimensional material layer 6 (i.e., the first metal electrode 8 and the second metal electrode 9), a dark current can be obtained. The difference between the photocurrent and the dark current is the photocurrent response of the photodetector.

[0058] It is worth mentioning that compared with the traditional method of heterogeneously integrating two-dimensional materials in a rectangular waveguide, the Mie waveguide 3 in the present application has a slow light effect in the communication band, which will enhance the interaction between light and matter inside and around the Mie waveguide 3. At the same time, the gold nanostrips 7 arranged on the top of the two-dimensional material layer 6 can further enhance the electric field, achieve high responsiveness and wide spectrum performance in the communication range, and thus improve the performance of the photodetector.

[0059] The performance of the Mie waveguide is exemplified below with reference to simulation experimental data.

[0060] Specifically, in the simulation of Mie waveguide using multi-physics (COMSOL Multiphysics), boundary mode analysis is used in conjunction with port boundary conditions to excite the TE polarization fundamental mode in the propagation direction, and an absorbing boundary condition perfect matching layer (PML) is applied around the Mie waveguide to achieve the absorption of light reflected on the Mie waveguide wall with the smallest possible reflectivity.

[0061] Among them, the wavelength of the incident light is 1550nm, and the strongest electric field is located at the edge of the Mie waveguide nanoparticle. The mode extends into the surrounding medium (such as silicon dioxide), which can help understand the sensitivity of the mode to the surrounding medium, making the Mie waveguide a good candidate for sensing applications.

[0062] Figure 4 The graph of Mie waveguide transmittance changing with the incident wavelength shows that for a Mie waveguide with a diameter D of 340 nm, a cylinder spacing g of 170 nm, and a height of 220 nm, the photonic band gap is located near a wavelength of 1540 nm. Below this wavelength, light propagation is prohibited.

[0063] Figure 5 The curves of electric field intensity and transmittance varying with the width of the metal strips. As the width of the gold nanostrips increases, the electric field intensity first increases and then decreases, and the Mie waveguide transmittance first decreases and then increases. When the width of the gold nanostrips is 170nm, the electric field strength is increased by two times compared to when no gold nanostrips are added, and the transmittance is the lowest at this time.

[0064] Figure 6 The curves of electric field intensity and transmittance varying with the height of the metal strips. As the height of the gold nanostrips increases, the electric field modulus increases first and then levels off, but the transmittance shows an upward trend. Therefore, increasing the height of the gold nanostrips can help improve the problem of low transmittance of the Mie waveguide.

[0065] Figure 7 Based on the rectangular waveguide, palladium selenide (PdSe 2 ) Current-voltage (IV) curves of a photodetector with a length of about 2μm under different light powers in the dark and at 1550nm. When the incident light power is 5mW and the bias voltage is 3V, the calculated photocurrent is 2.82mA.

[0066] Figure 8 PdSe based on Mie waveguide 2 The current-voltage (IV) curves of the photodetector with a length of about 2μm under different light powers in the dark and at 1550nm, the calculated photocurrent is about 3.33mA under the incident light power of 5mW and the bias voltage of 3V. It can be seen that the proposed Mie waveguide structure can significantly increase the light response of the photodetector compared with the traditional rectangular waveguide structure.

[0067] Fig. 9 PdSe based gold nanorods for enhanced Mie waveguides 2 The current-voltage (IV) curves of the photodetector with a length of about 2 μm under different light powers in the dark and at 1550 nm, the calculated photocurrent is about 4.19 mA at an incident light power of 5 mW and a bias voltage of 3 V. It can be seen that placing gold nanostrips on the Mie waveguide structure can further increase the light response of the photodetector compared to the Mie waveguide structure without gold nanostrips.

[0068] Fig.10 PdSe based gold nanorods for enhanced Mie waveguides 2 The relationship between the photocurrent and photoresponse and the incident power of a photodetector with a length of about 2μm, when the bias voltage is 3V. It can be seen that the photocurrent increases nonlinearly with the increase of the incident power, and the photoresponsivity decreases nonlinearly with the increase of the incident power.

[0069] Fig.11 PdSe based gold nanorods for enhanced Mie waveguides 2 The relationship curve between the photocurrent and waveguide transmittance of the photodetector and the thickness of the isolation layer shows that as the thickness of the isolation layer increases, the transmittance gradually increases, which is attributed to the enhanced total reflection effect of the isolation layer (silicon dioxide) on light.

[0070] Fig.12 The loss of Mie waveguide and PdSe 2 The relationship curve of layer thickness shows that the loss increases almost linearly with the thickness of the two-dimensional material.

[0071] Fig.13 PdSe based gold nanorods for enhanced Mie waveguides 2 Photodetector photocurrent and Mie waveguide transmittance vs. PdSe 2 Layer thickness relationship curve. As the thickness of the two-dimensional material increases, the photocurrent and transmittance change in opposite trends.

[0072] Fig.14 PdSe based gold nanorods for enhanced Mie waveguides 2 The light absorption rate η of the photodetector increases with the 2 Layer length variation curve. 2 When the material length L exceeds 20 μm, light absorption reaches saturation.

[0073] It can be seen from the above simulation experimental data that the Mie waveguide of the photodetector provided in the embodiment of the present application has a slow light effect in the communication band, which will enhance the interaction between light and matter inside and around the Mie waveguide. At the same time, the gold nanobars are combined to further enhance the electric field, so that the photodetector can achieve high responsiveness and wide spectrum performance in the communication range, thereby improving the performance of the photodetector.

[0074] In addition, Mie waveguide manufacturing is compatible with CMOS technology and is simpler to manufacture. By utilizing the simple structure, easy integration, and slow light effect in the communication band of Mie waveguide, the light absorption of two-dimensional materials can be maximized, thereby improving the performance of photodetectors.

[0075] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles described in the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A photoelectric detector based on slow light effect, characterized in that: include: Silicon substrate; A buried oxide layer is formed on the top of the silicon substrate, a Mie waveguide is provided on the top of the buried oxide layer, and rectangular waveguides are provided at both ends of the Mie waveguide; An isolation layer formed on top of the buried oxide layer, wherein the Mie waveguide and the rectangular waveguide are both located in the isolation layer; A two-dimensional material layer is formed on the top of the isolation layer, and a first metal electrode, a second metal electrode and a gold nanorod are arranged on the top of the two-dimensional material layer. The gold nanorod is located between the first metal electrode and the second metal electrode.

2. The photodetector according to claim 1, characterized in that: Mie waveguides are made of chains of cylindrical nanotubes.

3. The photodetector according to claim 2, characterized in that: The diameter of the cylinder in the cylindrical nanochain is 300nm to 340nm, and the distance between two adjacent cylinders in the cylindrical nanochain is 130nm to 170nm.

4. The photodetector according to claim 1, characterized in that: The thickness of the Mie waveguide and the rectangular waveguide are both 150nm to 220nm, and the width of the rectangular waveguide is 300nm to 340nm.

5. The photodetector according to claim 1, characterized in that: The material of the Mie waveguide is one of silicon, germanium, silicon-germanium mixture and silicon nitride.

6. The photodetector according to claim 1, characterized in that: The width of the gold nanorod is 150nm to 200nm, the height is 100nm to 200nm, and the length of the gold nanorod is equal to the sum of the length of the Mie waveguide and the length of the two rectangular waveguides.

7. The photodetector according to claim 1, characterized in that: The silicon substrate has a thickness of 700 μm to 900 μm.

8. The photodetector according to claim 1, characterized in that: The thickness of the buried oxide layer is 2 μm to 3 μm.

9. The photodetector according to claim 1, characterized in that: The thickness of the isolation layer is 10 nm to 100 nm, and the material of the isolation layer is silicon dioxide, Al2O3 or hexagonal boron nitride.

10. The photodetector according to claim 1, characterized in that: The thickness of the two-dimensional material layer is 30nm to 150nm. The two-dimensional material layer is a two-dimensional material layer composed of one two-dimensional material, or a heterojunction formed by combining two two-dimensional materials. The two-dimensional material is palladium selenide, MoTe2, and PtSe2.

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