Enhanced waveguide integrated photoelectric detector for MIR wave band

Abstract

The invention belongs to the field of integrated optics, and particularly relates to an enhanced waveguide integrated photoelectric detector for an MIR wave band, in the photoelectric detector, a waveguide structure layer is mainly composed of a suspended waveguide in the center and sub-wavelength gratings on the two sides, buried oxide layers are removed below the suspended waveguide and the sub-wavelength gratings in an etching mode and the like, and therefore the photoelectric detector is formed. Forming an air gap; the light in the waveguide interacts with the two-dimensional material layer above through the evanescent field; compared with a traditional two-dimensional material heterogeneous integrated silicon waveguide photoelectric detector working in an NIR wave band, the enhanced waveguide integrated photoelectric detector has high response in the MIR wave band, meanwhile, the gold nanosphere array on the top can further limit a light field to a two-dimensional material layer, the interaction between light and substances is enhanced, and the photoelectric detector has the advantages that the photoelectric detector is simple in structure and convenient to operate. Therefore, the performance of the photoelectric detector is improved, and the influence on waveguide transmission loss is very small and even can be ignored.

Description

Technical Field

[0001] The present invention relates to the field of integrated optical technology, and in particular to an enhanced waveguide integrated photoelectric detector for MIR band. Background Art

[0002] With the rapid development of information technology, modern communication systems have an increasing demand for transmission rate and bandwidth. Optical communication technology has gradually replaced traditional electrical connection technology with its advantages of low loss and high speed, becoming the first choice for medium and long distance transmission. In optical communication systems, photodetectors are core components, and their performance directly determines the performance upper limit of the entire system. Therefore, the development of photodetectors with wide spectral response, high responsivity, large bandwidth and low dark current is crucial to the realization of high-speed on-chip interconnection systems.

[0003] In the past decade, silicon photonics technology based on silicon-on-insulator (SOI) platform has attracted extensive research interest. Various silicon waveguide integrated photodetectors have shown excellent performance in the near-infrared band (NIR, usually around 1μm-2μm wavelength). However, mid-infrared band (MIR) waveguide integrated photodetectors based on SOI platform are relatively rare, mainly because the buried oxide layer (BOX) absorbs light more in the MIR band. Summary of the invention

[0004] The embodiment of the present invention provides an enhanced waveguide integrated photodetector for the MIR band, aiming to improve the performance of the photodetector and broaden its application band range in the field of precision measurement to meet the demand for high-performance detection technology.

[0005] To achieve the above object, the present invention provides an enhanced waveguide integrated photodetector for MIR band, comprising a silicon substrate, a buried oxide layer, a waveguide structure layer and a two-dimensional material layer stacked in sequence from bottom to top, wherein a gold nanosphere array, a first metal electrode and a second metal electrode are arranged on the top of the two-dimensional material layer;

[0006] The waveguide structure layer includes a suspended waveguide located in the middle position, sub-wavelength gratings located on both sides of the suspended waveguide, and a silicon film located on the side of the sub-wavelength grating away from the suspended waveguide; the buried oxide layer located below the suspended waveguide and the sub-wavelength grating is removed to form an air gap; the gold nanosphere array is located directly above the suspended waveguide, the first metal electrode and the second metal electrode are respectively located on both sides of the top of the two-dimensional material layer, and the first metal electrode, the second metal electrode and the two-dimensional material layer are connected to form a conductive path.

[0007] Optionally, the width d of the suspension waveguide is 1100nm-1500nm; the length a of the sub-wavelength gratings located on both sides of the suspension waveguide is 2500nm-3000nm, the width b is 100nm-200nm, and the gap c is 300nm-500nm.

[0008] Optionally, the thickness h1 of the waveguide structure layer is 400nm-600nm.

[0009] Optionally, the material of the waveguide structure layer is one of silicon, germanium, a silicon-germanium mixture and silicon nitride.

[0010] Optionally, the gold nanosphere array comprises a plurality of gold nanospheres arranged in a linear array, the radius r of the gold nanosphere is 150nm-500nm, and the distance between two adjacent gold nanospheres is 800nm-1200nm.

[0011] Optionally, the radius r of the gold nanosphere is 0.3 μm, and the distance between two adjacent gold nanospheres is 1 μm.

[0012] Optionally, a thickness h3 of the silicon substrate is 700 μm-900 μm.

[0013] Optionally, the thickness h2 of the buried oxide layer is 2 μm-5 μm.

[0014] Optionally, the thickness h of the two-dimensional material layer is 10nm-150nm.

[0015] Optionally, the two-dimensional material layer is composed of one two-dimensional material or forms a heterostructure layer with two two-dimensional materials, and the two-dimensional material is PdSe2 or PtSe2.

[0016] The enhanced waveguide integrated photodetector for the MIR band provided by the present invention has the following beneficial effects: compared with the prior art, in the enhanced waveguide integrated photodetector for the MIR band, the waveguide structure layer is mainly composed of a suspended waveguide in the center and subwavelength gratings on both sides, and the buried oxide layer is removed below the suspended waveguide and the subwavelength grating by etching or the like to form an air gap; the light in the waveguide interacts with the two-dimensional material layer above through the evanescent field; compared with the traditional two-dimensional material heterogeneous integrated silicon waveguide photodetector working in the NIR band, the enhanced waveguide integrated photodetector of the present application has a higher response in the MIR band, and at the same time, the gold nanosphere array on the top can further confine the light field to the two-dimensional material layer, enhance the interaction between light and matter, thereby improving the performance of the photodetector, and the influence on the waveguide transmission loss is very small, even negligible. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] in:

[0019] Figure 1 is a cross-sectional schematic diagram of an enhanced waveguide integrated photodetector for MIR bands shown in one embodiment of the present invention;

[0020] Figure 2 is a top view of an enhanced waveguide integrated photodetector for MIR bands shown in one embodiment of the present invention;

[0021] Figure 3 is a graph of the photocurrent response and transmittance of the photodetector as a function of the radius of the gold nanosphere;

[0022] Figure 4 is a graph of the photocurrent response and transmittance of the photodetector as a function of the distance between gold nanospheres;

[0023] Figure 5 This is a comparison chart of the transmittance of the photodetector without and with the gold nanosphere array in the 3μ-4μm band;

[0024] Figure 6 This is a comparison of the responsivity of the photodetector without and with the gold nanosphere array in the 3μ-4μm band;

[0025] Figure 7 is the current-voltage (IV) curve of the photodetector without and with the gold nanosphere array at a wavelength of 3800 nm;

[0026] Figure 8 1 is a graph showing the responsivity and photocurrent of an enhanced waveguide integrated photodetector for the MIR band at different input optical powers according to an embodiment of the present invention.

[0027] Description of main component symbols:

[0028] 1. Suspended waveguide; 2. Gold nanosphere array; 3. First metal electrode; 4. Second metal electrode; 5. Two-dimensional material layer; 6. Subwavelength grating; 7. Silicon film; 8. Air gap; 9. Buried oxide layer; 10. Silicon substrate. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0030] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0031] It should be understood that the terms "length", "width", "up", "down", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0033] As described in the background art, mid-infrared (MIR) waveguide integrated photodetectors based on SOI platforms are relatively rare, mainly due to the large absorption of light by the buried oxide layer (BOX) in the MIR band.

[0034] In order to solve the above problems, the embodiments of the present invention provide an enhanced waveguide integrated photodetector for the MIR band, in which a suspended silicon waveguide is used to effectively avoid the above problems, and on this basis, the interaction between the light field and the material is enhanced to improve the responsiveness of the device. In addition to the optimization of the waveguide structure, a suitable external material is selected to efficiently absorb photons in the evanescent field.

[0035] like Figure 1-Figure 2As shown, the enhanced waveguide integrated photodetector comprises a silicon substrate 10, a buried oxide layer 9, a waveguide structure layer and a two-dimensional material layer 5 stacked in sequence from bottom to top, and a gold nanosphere array 2, a first metal electrode 3 and a second metal electrode 4 are arranged on the top of the two-dimensional material layer 5. The waveguide structure layer comprises a suspended waveguide 1 located in the middle, sub-wavelength gratings 6 located on both sides of the suspended waveguide 1, and a silicon film 7 located on the side of the sub-wavelength grating 6 away from the suspended waveguide 1; the buried oxide layer 9 located below the suspended waveguide 1 and the sub-wavelength grating 6 is removed to form an air gap 8; the gold nanosphere array 2 is located directly above the suspended waveguide 1, the first metal electrode 3 and the second metal electrode 4 are respectively located on both sides of the top of the two-dimensional material layer 5, and the first metal electrode 3, the second metal electrode 4 and the two-dimensional material layer 5 are connected to form a conductive path.

[0036] In the enhanced waveguide integrated photodetector for the MIR band, the waveguide structure layer is mainly composed of a suspended waveguide 1 in the center and subwavelength gratings 6 on both sides. The buried oxide layer 9 is removed below the suspended waveguide 1 and the subwavelength grating 6 by etching or the like to form an air gap 8. The light in the waveguide interacts with the two-dimensional material layer 5 above through the evanescent field. Compared with the traditional two-dimensional material heterogeneous integrated silicon waveguide photodetector working in the NIR band, the enhanced waveguide integrated photodetector of the present application has a higher response in the MIR band. At the same time, the gold nanosphere array 2 on the top can further confine the light field to the two-dimensional material layer 5, enhance the interaction between light and matter, thereby improving the performance of the photodetector, and the impact on the waveguide transmission loss is very small, even negligible.

[0037] Among them, the suspended waveguide 1 is a waveguide structure suspended above the air gap 8, and the sub-wavelength gratings 6 on both sides can provide a support. Specifically, when preparing the waveguide structure layer, firstly, an air hole pattern is formed on the silicon substrate by electron beam lithography technology, and then deep reactive ion etching (DRIE) is used to completely etch to the BOX layer so as to have straight and smooth side walls. Then, a hydrofluoric acid (HF) solution is used to remove the BOX layer to suspend the silicon waveguide structure, and then the waveguide is released by gaseous HF treatment to ensure that it is completely separated from the substrate to form a stable suspended waveguide structure. The waveguide structure layer propagates in the TE polarization fundamental mode. The width d and thickness h1 of the suspended waveguide 1 and the spacing c and width b of the sub-wavelength grating 6 will affect the propagation of the incident light. Adjusting the above parameters can achieve the regulation of the transmission band and transmission loss.

[0038] After the preparation of the waveguide structure layer is completed, the two-dimensional material layer 5 needs to be transferred to the top of the waveguide structure layer, which can be completed by mechanical stripping. Mechanical stripping is to directly strip the two-dimensional material from a suitable substrate by physical means. This process needs to be carried out under an optical microscope, and transparent tape is used to assist in stripping the two-dimensional material. First, a bulk layered sheet of the two-dimensional material is placed on a transparent tape, and the bulk material is stripped by repeated pasting to make it a thinner layered sheet. After stripping, the layered sheet on the tape is transferred to a polydimethylsiloxane (PDMS) film, and then the PDMS film is transferred to the target substrate (waveguide structure layer) together with the two-dimensional material, and the PDMS film is slowly stripped after a period of rest. Because the adsorption force of PDMS is small when the stripping speed is slow, the two-dimensional material is more inclined to be adsorbed to the surface of the target substrate, and finally the two-dimensional material is left above the waveguide structure layer. The thickness h of the two-dimensional material layer 5 can be measured by an atomic force microscope (AFM).

[0039] Then, positive or negative photoresist is used for photolithography to define the position and shape of the electrode. A metal layer is deposited in the area defined by the photoresist by electron beam evaporation or sputtering deposition technology to form a metal electrode (i.e., a first metal electrode 3 and a second metal electrode 4, the material of which can be gold). Finally, a gold nanosphere array 2 can be made on the suspension waveguide 1 and the two-dimensional material layer 5 by methods such as 3D printing. The gold nanosphere array 2 formed above the suspension waveguide 1 forms a bound state of a radiation mode in the two-dimensional material layer 5, so that the electromagnetic wave can be well confined in the two-dimensional material layer 5, thereby improving the interaction between light and matter, thereby improving the performance of the photodetector.

[0040] In some embodiments of the present application, in order to improve the performance of the photodetector, the width d of the above-mentioned suspended waveguide 1 is 1100nm-1500nm, the length a of the sub-wavelength grating 6 is 2500nm-3000nm, the width b is 100nm-200nm, and the gap c is 300nm-500nm. The thickness h1 of the waveguide structure layer (that is, the thickness of the suspended waveguide 1 and the sub-wavelength grating 6) is 400nm-600nm, and the material is one of silicon, germanium, silicon germanium mixed and silicon nitride to meet the transmission of MIR band light.

[0041] The gold nanosphere array 2 includes a plurality of gold nanospheres arranged in a linear array along the length direction of the suspension waveguide 1. In some embodiments of the present application, the radius r of the gold nanospheres in the gold nanosphere array 2 is 300nm-500nm, and the distance between two adjacent gold nanospheres is 800nm-1200nm.

[0042] In some embodiments of the present application, the thickness h3 of the silicon substrate 10 is 700 μm-900 μm, and the thickness h2 of the buried oxide layer 9 is 2 μm-5 μm. The thickness h of the two-dimensional material layer 5 is 10 nm-150 nm, and the two-dimensional material layer 5 is composed of one two-dimensional material or a heterostructure layer formed by two two-dimensional materials, and the two-dimensional material is PdSe2 or PtSe2. Van der Waals materials overcome the limitations caused by the differences in lattice constants and thermal expansion coefficients between material platforms with their unique physical properties, and show high compatibility with any substrate. For example, graphene, black phosphorus, and noble metal selenides such as PdSe2 and PtSe2 all have good absorption capabilities in the MIR band. However, the high dark current caused by the zero band gap of graphene and the instability of black phosphorus in air hinder their further widespread application. In comparison, PdSe2 and PtSe2 have good air stability, high carrier mobility, and effective light absorption capabilities in the MIR band, making them strong candidate materials for waveguide integrated detectors.

[0043] It can be understood that the shapes, materials and sizes of the silicon substrate 10, buried oxide layer 9, suspended waveguide 1, subwavelength grating 6, silicon film 7, two-dimensional material layer 5 and gold nanosphere array 2 in the above embodiments are preferred and are not limited thereto, and can be adjusted according to actual conditions.

[0044] It should be noted that the two-dimensional material layer 5 is located between the gold nanosphere array 2 and the suspension waveguide 1, and the light propagating in the suspension waveguide 1 interacts with the two-dimensional material layer 5 through evanescent field coupling. The gold nanosphere array 2 can form a bound state of the radiation mode in the two-dimensional material layer 5, so that the electromagnetic wave can be well confined in the two-dimensional material layer 5, thereby improving the interaction between light and matter, thereby improving the performance of the photodetector.

[0045] Specifically, by adjusting the radius and spacing of the balls in the gold nanosphere array 2, the enhancement effect and waveguide transmission performance can be optimized; by adjusting the thickness and length of the two-dimensional material layer 5, the responsiveness and waveguide loss of the photodetector can be optimized. It should be noted that the silicon substrate 10 in the enhanced waveguide integrated photodetector for the MIR band in the embodiment of the present application is mainly used to provide support and foundation, and the buried oxide layer 9 is mainly used to improve electrical insulation and overall performance. Since the buried oxide layer 9 under the suspended waveguide 1 and the sub-wavelength grating 6 is etched, an air gap 8 is formed, thereby greatly reducing the influence of the buried oxide layer 9 on the light absorption of the MIR band.

[0046] The above-mentioned electrode pair (i.e., the first metal electrode 3 and the second metal electrode 4) is used to apply bias voltage and measure current. When the incident light is coupled into the suspended waveguide 1 for transmission, the light interacts with the two-dimensional material layer 5 through evanescent field coupling, thereby generating current. Applying a bias voltage at both ends of the two-dimensional material layer 5 (i.e., the first metal electrode 3 and the second metal electrode 4) can enhance the magnitude of the response current. When there is no incident light, a bias voltage is applied to the electrodes at both ends of the two-dimensional material layer 5 (i.e., the first metal electrode 3 and the second metal electrode 4) to obtain a dark current. The difference between the response current and the dark current is the photocurrent response of the photodetector.

[0047] It is worth mentioning that compared with the traditional waveguide integrated photodetector working in the NIR band, the structure of the suspended waveguide 1 of the present application enables it to transmit and detect in the MIR band, and the gold nanosphere array 2 arranged above the suspended waveguide 1 can form a bound state of the radiation mode in the two-dimensional material layer 5, so that the electromagnetic waves can be well confined in the two-dimensional material layer 5, further improving the interaction between light and matter, thereby improving the performance of the photodetector, and achieving high responsiveness and wide spectrum performance in the communication range.

[0048] The performance of the suspended waveguide 1 is exemplarily described below in conjunction with simulation experiment data.

[0049] Specifically, in the simulation of the suspended waveguide using multiphysics (COMSOL Multiphysics), the boundary mode analysis is used in conjunction with the port boundary conditions to excite the TE polarization fundamental mode in the propagation direction, and the absorption boundary condition perfect matching layer (PML) is applied around the suspended waveguide to achieve the absorption of the light reflected on the waveguide wall with the smallest possible reflectivity. The wavelength of the incident light is 3μm-4μm, and the simulation temperature is set to 293K.

[0050] Figure 3 The graph of photocurrent and port transmittance changing with the radius of gold nanospheres shows that as the radius of the gold nanospheres increases from 0.15μm to 0.30μm, the photocurrent response of the photodetector gradually increases, and the port transmittance gradually decreases. However, it is worth noting that when the radius increases to 0.3μm, the photocurrent increases by about 26.0%, while the port transmittance only decreases by about 1.2%. This shows that the increase in the radius of the gold nanospheres significantly improves the photocurrent response of the photodetector, while the corresponding port transmittance loss is very small.

[0051] Figure 4 The graph below shows the photocurrent and port transmittance as the distance between adjacent gold nanospheres changes. As the distance between the spheres increases from 0.8μm to 1.2μm, the photocurrent response of the photodetector is the largest when the distance is 1.0μm, while the port transmittance shows a gradual downward trend. Figure 3 and Figure 4Based on the data, the sphere radius of the gold nanosphere array 2 is 0.3 μm and the spacing is 1.0 μm as the optimal parameter settings, which can maximize the performance of the photodetector under the condition of small loss.

[0052] Figure 5 This is a comparison chart of the transmittance of the photodetector without gold nanosphere array 2 and with gold nanosphere array 2 in the 3μm-4μm band. The output port transmittance of the photodetector without gold nanosphere array 2 in this band is maintained at about 78%, showing good stability. In contrast, after the introduction of gold nanosphere array 2, the transmittance of the output port fluctuates slightly around 75%. This result shows that although gold nanosphere array 2 has a certain influence on the transmission performance of the photodetector, the influence is relatively limited.

[0053] Figure 6 The responsivity comparison of PdSe2-based photodetectors without gold nanosphere array 2 and with gold nanosphere array 2 in the 3μm-4μm band, with an input light power of 20μW, a bias voltage of 5V, and a PdSe2 length of about 5μm is shown. Specifically, the responsivity of the photodetector without gold nanosphere array 2 in this band is about 0.6A / W. When gold nanosphere array 2 is introduced, the responsivity of the enhanced photodetector in the same band is significantly improved. In particular, at a wavelength of 3.2μm, the responsivity increases by more than 300%, showing the significant enhancement effect of gold nanosphere array 2 on the performance of the photodetector.

[0054] Figure 7 The current-voltage (IV) curves of the PdSe2-based photodetector without and with the gold nanosphere array 2 at a wavelength of 3800nm, an input light power of 20μW, and a PdSe2 length of about 5μm are shown. It is easy to observe that the addition of the gold nanosphere array 2 can improve the performance of the photodetector to a certain extent, and the improvement effect is more obvious as the bias voltage increases. When the bias voltage is 5V, the photocurrent response of the ordinary suspended waveguide integrated photodetector is about 16μA, but the photocurrent response of the enhanced waveguide integrated photodetector is about 32μA, which is twice that of the former.

[0055] Figure 8The responsivity and photocurrent change curves of the enhanced waveguide integrated photodetector at different input light powers are shown under the conditions of 3800nm ​​wavelength, PdSe2 length of about 5μm, and bias voltage of 5V. As the input light power increases, the photocurrent generated by the photodetector shows a gradual increase, but its responsivity shows a decreasing trend. Specifically, at a lower input light power (0.1μW), the responsivity of the photodetector reaches about 25A / W; at a higher input light power (600μW), the photocurrent of the photodetector is about 160μA.

[0056] It can be seen from the above simulation experiment data that the enhanced waveguide integrated photodetector for the MIR band provided in the embodiment of the present application broadens the detection spectrum, breaks through the working limitations of the traditional waveguide integrated photodetector in the near-infrared band, and expands its application range to the MIR band for the first time. In addition, by introducing the gold nanosphere array 2, the design not only significantly improves the performance of the detector, but also optimizes the array layout parameters to ensure that the impact on the waveguide transmission loss is minimized. The simulation experiment data show that the enhanced waveguide integrated photodetector provided in the embodiment of the present invention achieves a significant enhancement in detection performance without sacrificing transmission efficiency.

[0057] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. An enhanced waveguide integrated photodetector for MIR band, characterized in that: It comprises a silicon substrate, a buried oxide layer, a waveguide structure layer and a two-dimensional material layer stacked in sequence from bottom to top, wherein a gold nanosphere array, a first metal electrode and a second metal electrode are arranged on the top of the two-dimensional material layer; The waveguide structure layer includes a suspended waveguide located in the middle, sub-wavelength gratings located on both sides of the suspended waveguide, and a silicon film located on a side of the sub-wavelength grating away from the suspended waveguide; The buried oxide layer located below the suspended waveguide and the sub-wavelength grating is removed to form an air gap; the gold nanosphere array is located directly above the suspended waveguide, the first metal electrode and the second metal electrode are respectively located on both sides of the top of the two-dimensional material layer, and the first metal electrode, the second metal electrode and the two-dimensional material layer are connected to form a conductive path.

2. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The width d of the suspension waveguide is 1100nm-1500nm; the length a of the sub-wavelength gratings located on both sides of the suspension waveguide is 2500nm-3000nm, the width b is 100nm-200nm, and the gap c is 300nm-500nm.

3. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The thickness h1 of the waveguide structure layer is 400nm-600nm.

4. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The material of the waveguide structure layer is one of silicon, germanium, silicon-germanium mixture and silicon nitride.

5. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The gold nanosphere array comprises a plurality of gold nanospheres arranged in a linear array, the radius r of the gold nanospheres is 150nm-500nm, and the distance between two adjacent gold nanospheres is 800nm-1200nm.

6. The enhanced waveguide integrated photodetector for MIR band according to claim 5, characterized in that: The radius r of the gold nanosphere is 0.3 μm, and the distance between two adjacent gold nanospheres is 1 μm.

7. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The thickness h3 of the silicon substrate is 700 μm-900 μm.

8. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The thickness h2 of the buried oxide layer is 2 μm-5 μm.

9. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The thickness h of the two-dimensional material layer is 10nm-150nm.

10. The enhanced waveguide integrated photodetector for MIR band according to claim 1, characterized in that: The two-dimensional material layer is composed of one two-dimensional material or a heterostructure layer formed by two two-dimensional materials, and the two-dimensional material is PdSe2 or PtSe2.

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