A photoelectric detector

Abstract

The present invention discloses a photodetector, which relates to the field of optoelectronic technology, and localizes an optical signal into a graphene layer through a slit waveguide portion provided with a Bragg resonant cavity, and enhances the interaction between the optical signal and the graphene layer, so as to improve the photodetection responsivity of the photodetector when working. The photodetector comprises: a substrate, an optical waveguide structure, a graphene layer, a first electrode and a second electrode. The optical waveguide structure is formed on the substrate. The optical waveguide structure comprises a slit waveguide portion provided with a Bragg resonant cavity. The graphene layer at least covers the slit waveguide portion. The slit waveguide portion is used to localize the optical signal into the graphene layer. The first electrode and the second electrode are formed above the substrate. The first electrode is electrically connected to the optical waveguide structure, and is used to derive a first type of carrier under the action of an external electric field. The second electrode is electrically connected to the graphene layer, and is used to derive a second type of carrier under the action of an external electric field. The electrical properties of the first type of carrier and the second type of carrier are opposite.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technology, and in particular to a photoelectric detector. Background Art

[0002] Photodetectors are devices that convert light signals into electrical signals based on the photoelectric effect, thereby measuring light radiation. Among them, graphene materials have excellent optical properties, which makes graphene-based photodetectors have the advantages of low power consumption, small size and easy integration, making graphene photodetectors widely used in the field of optical communications.

[0003] However, the existing graphene photodetector has a low photodetection responsivity during normal operation, resulting in poor working performance of the graphene photodetector. Summary of the invention

[0004] The object of the present invention is to provide a photodetector, which localizes the optical signal into a graphene layer through a slit waveguide portion provided with a Bragg resonant cavity, enhances the interaction between the optical signal and the graphene layer, improves the photodetection responsiveness of the photodetector during operation, and enhances the working performance of the photodetector.

[0005] In order to achieve the above objective, the present invention provides a photodetector, which includes: a substrate, an optical waveguide structure, a graphene layer, a first electrode and a second electrode.

[0006] The optical waveguide structure is formed on a substrate. The optical waveguide structure includes a slit waveguide portion provided with a Bragg resonant cavity. The graphene layer at least covers the slit waveguide portion. The slit waveguide portion is used to localize the optical signal into the graphene layer. A first electrode and a second electrode are formed above the substrate. The first electrode is electrically connected to the optical waveguide structure and is used to derive a first type of carrier under the action of an external electric field. The second electrode is electrically connected to the graphene layer and is used to derive a second type of carrier under the action of an external electric field. The first type of carrier and the second type of carrier have opposite electrical properties.

[0007] Compared with the prior art, in the photodetector provided by the present invention, an optical waveguide structure is formed on the substrate, and the optical waveguide structure includes a slit waveguide portion provided with a Bragg resonant cavity. Based on this, during the operation of the photodetector, the slit waveguide portion is used to transmit the optical signal, and it can localize the optical signal in the Bragg resonant cavity to the slit groove of the slit waveguide portion. At the same time, because the graphene layer at least covers the slit waveguide portion, the slit waveguide portion can localize the transmitted optical signal to the graphene layer. Based on this, in practical applications, after absorbing the energy of the photons in the optical signal, the graphene layer can excite the first type of carriers and the second type of carriers that exist in pairs. In addition, the corresponding voltage provided by the external electric field can be loaded onto the graphene layer and the optical waveguide structure through the first electrode and the second electrode, so that the first type of carriers and the second type of carriers that exist in pairs are separated and directed under the action of the external electric field. The first type of carriers are derived through the first electrode, and the second type of carriers are derived through the second electrode, thereby forming a photocurrent and realizing the detection of the optical signal.

[0008] Moreover, while the first type of carriers and the second type of carriers are separated and directed to move under the action of an external electric field, the imaginary part of the effective refractive index of the graphene layer can be increased, that is, the absorption coefficient of the graphene layer to the light signal is increased, thereby improving the photoelectric detection responsiveness of the photodetector when it is working. Moreover, the Bragg resonant cavity provided at the slit waveguide portion can make the light signal reflect back and forth in the graphene layer within the range of the Bragg resonant cavity, thereby enhancing the interaction between the light signal and the graphene layer, thereby further improving the photoelectric detection responsiveness of the photodetector when it is working and improving the working performance of the photodetector. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0010] Figure 1 A schematic diagram of the three-dimensional structure of a photoelectric detector provided in an embodiment of the present invention;

[0011] Figure 2 Schematic diagram of the top view of the structure of the slot waveguide portion in an embodiment of the present invention.

[0012] Reference numerals:

[0013] 1 is the base,

[0014] 2 is an optical waveguide structure, 21 is a slit waveguide portion, 211 is a strip waveguide,

[0015] 212 is a slit slot, 213 is a Bragg resonant cavity, 214 is an adjustment slot,

[0016] 22 is a connecting portion,

[0017] 3 is a graphene layer,

[0018] 4 is a first electrode,

[0019] 5 is a second electrode. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0021] Various structural schematic diagrams according to embodiments of the present disclosure are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may further design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0022] In the context of the present disclosure, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the 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. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] A photodetector is a device that converts light signals into electrical signals based on the photoelectric effect, thereby measuring light radiation. Among them, the above-mentioned photoelectric effect can be divided into external photoelectric effect and internal photoelectric effect. Specifically, the external photoelectric effect is the behavior of a material escaping electrons by absorbing photons. When a photodetector based on the external photoelectric effect is working, a positive voltage is applied to both the cathode and the anode. When the light signal is irradiated to the cathode surface, the cathode generates electrons, and a photoelectron flow is formed under the action of the voltage, so that the two poles are turned on to detect the light signal. The internal photoelectric effect (which can be divided into photoconductivity effect and photovoltaic effect) refers to the change in the material of the material itself caused by the action of light quanta. At this time, the electrons and holes excited by the photons are retained inside the material. Among them, after the photodetector based on the photoconductivity effect is irradiated by the light signal to excite electron-hole pairs, the carrier concentration inside it increases, which increases its own conductivity, so the light signal can be detected by measuring the size of the conductivity. When a photodetector based on the photovoltaic effect is irradiated by a light signal, the excited electron-hole pairs are separated by the built-in electric field and accumulated on both sides of the junction, generating a potential difference. When the external circuit is connected, a photocurrent is generated, and the light signal is detected by measuring the size of the photocurrent.

[0026] Among them, graphene-based photodetectors are a type of photodetectors based on the internal photoelectric effect. In addition, graphene materials have excellent optical properties, which makes graphene-based photodetectors have the advantages of low power consumption, small size and easy integration, thus making graphene photodetectors widely used in the field of optical communications.

[0027] However, in the working process of existing graphene photodetectors, the interaction between the transmitted light signal and graphene is weak, resulting in lower photon energy absorbed by graphene, which in turn causes a decrease in the photocurrent formed by the photodetector. Based on this, since the photodetection responsivity of the photodetector is proportional to the photocurrent it forms, when the photocurrent decreases, the photodetection responsivity will also decrease, which in turn causes poor working performance of the graphene photodetector.

[0028] In order to solve the above technical problems, an embodiment of the present invention provides a photodetector. In the photodetector, the optical waveguide structure includes a slit waveguide portion provided with a Bragg resonant cavity. And, at least the slit waveguide portion is covered with a graphene layer. Based on this, when the photodetector is working, the Bragg resonant cavity provided at the slit waveguide portion can make the optical signal reflect back and forth in the graphene layer within the range of the Bragg resonant cavity, thereby enhancing the interaction between the optical signal and the graphene layer, and then can improve the photoelectric detection responsiveness of the photodetector when working, and improve the working performance of the photodetector.

[0029] like Figure 1 As shown, an embodiment of the present invention provides a photodetector. The photodetector includes: a substrate 1 , an optical waveguide structure 2 , a graphene layer 3 , a first electrode 4 and a second electrode 5 .

[0030] like Figure 1 and Figure 2 As shown, the above-mentioned optical waveguide structure 2 is formed on a substrate 1. The optical waveguide structure 2 includes a slit waveguide portion 21 provided with a Bragg resonant cavity 213. The graphene layer 3 at least covers the slit waveguide portion 21. The slit waveguide portion 21 is used to localize the optical signal into the graphene layer 3. The first electrode 4 and the second electrode 5 are formed above the substrate 1. The first electrode 4 is electrically connected to the optical waveguide structure 2, and is used to derive the first type of carriers under the action of an external electric field. The second electrode 5 is electrically connected to the graphene layer 3, and is used to derive the second type of carriers under the action of an external electric field. The first type of carriers and the second type of carriers have opposite electrical properties.

[0031] Specifically, the substrate may be a semiconductor substrate on which no film layer is formed, for example, the substrate may be a silicon-based substrate such as a silicon substrate or a silicon-on-insulator substrate.

[0032] For the above optical waveguide structure, the structure and specifications of the slot waveguide portion included in the optical waveguide structure, and the specifications of the Bragg resonant cavity arranged on the slot waveguide portion can be set according to the optical parameters (e.g., wavelength) of the optical signal to be detected, the Bragg reflection conditions, and actual needs. Figure 2 As shown, the slit waveguide portion 21 may have at least two strip waveguides 211 and a slit groove 212 located between adjacent strip waveguides 211. In addition, the material of the optical waveguide structure may be set according to actual needs and is not specifically limited here. For example, the material of the optical waveguide structure may be silicon.

[0033] In some cases, such as Figure 1As shown, the optical waveguide structure 2 may further include a connection portion 22 formed on the substrate 1. The first electrode 4 is electrically connected to the slit waveguide portion 21 through the connection portion 22. The specific structure and specification of the connection portion 22 may be set according to the actual application scenario, as long as the first electrode 4 and the slit waveguide portion 21 can be electrically connected through the connection portion 22. For example: along the width direction of the slit waveguide portion 21, the connection portion 22 may be located on one side of the slit waveguide portion 21. Moreover, the thickness of the connection portion 22 may be less than the thickness of the slit waveguide portion 21. In addition, the connection portion 22 may be integrally formed with the slit waveguide portion 21. At this time, the connection portion 22 may be formed on the substrate 1 while the slit waveguide portion 21 is formed by etching based on the same film layer, thereby improving the manufacturing efficiency of the photodetector and reducing the manufacturing cost of the photodetector.

[0034] For the above graphene layer, the thickness of the graphene layer can be set according to the actual application scenario. Figure 1 As shown, the thickness of the graphene layer 3 can be greater than or equal to the height of the slot waveguide portion 21. At this time, the graphene layer 3 can fill the slot groove 212 of the slot waveguide portion 21, so that most of the optical signal transmitted through the slot waveguide portion 21 is located in the graphene layer 3, further enhancing the interaction between the optical signal and the graphene layer 3. Of course, the thickness of the graphene layer can also be less than the height of the slot waveguide portion.

[0035] In addition, the coverage of the graphene layer on the substrate can also be set according to the actual application scenario. Specifically, the graphene layer can only cover the top of the slot waveguide portion. Or, Figure 1 As shown, the graphene layer 3 may also cover the surface of the substrate 1 where the optical waveguide structure 2 is exposed, so that the second electrode 5 is electrically connected to the graphene layer 3 .

[0036] For the above-mentioned first electrode and second electrode, the shape and specification of the first electrode and the second electrode, as well as the specific position of the two above the substrate can be set according to the actual application scenario, as long as they can be applied to the photodetector provided in the embodiment of the present invention. In addition, the material of the first electrode and the second electrode can be a conductive metal material. For example: the above-mentioned conductive metal material can be gold, copper or aluminum. Among them, because copper and aluminum are commonly used metal materials in CMOS technology, when the material of the first electrode and the second electrode is copper or aluminum, it is conducive to the compatibility of the manufacturing process of the photodetector with the CMOS process, so that the photodetector provided in the embodiment of the present invention can be manufactured by a mature CMOS process, which can improve the manufacturing yield of the photodetector while facilitating the miniaturization of the photodetector.

[0037] In actual application, Figure 1 and Figure 2As shown, the slit waveguide portion 21 is used to transmit the optical signal to be detected, and it can localize the optical signal in the Bragg resonant cavity 213 to the slit groove 212 of the slit waveguide portion 21. At the same time, because the graphene layer 3 at least covers the slit waveguide portion 21, the slit waveguide portion 21 can localize the transmitted optical signal to the graphene layer 3 located in the slit groove 212. In addition, because the band gap of graphene is zero, the graphene layer 3 can excite the first type of carriers and the second type of carriers that exist in pairs after absorbing the energy of the photons in the optical signal. And the corresponding voltage provided by the external electric field can be loaded onto the graphene layer 3 and the optical waveguide structure 2 through the first electrode 4 and the second electrode 5, so that the above-mentioned first type of carriers and the second type of carriers that exist in pairs are separated and directed under the action of the external electric field. The first type of carriers are derived through the first electrode 4, and the second type of carriers are derived through the second electrode 5, thereby forming a photocurrent to achieve detection of the optical signal. At the same time, under the action of an external electric field, the imaginary part of the effective refractive index of the graphene layer 3 can also be increased, that is, the absorption coefficient of the graphene layer 3 to the optical signal can be increased, so that the graphene layer 3 can absorb more photon energy, thereby exciting more first-type carriers and second-type carriers, and then the photocurrent formed can be increased. Based on this, since the photodetection responsivity of the photodetector is proportional to the photocurrent, when the photocurrent increases, the photodetection responsivity of the photodetector also increases. Moreover, the Bragg resonant cavity 213 arranged at the slit waveguide portion 21 can make the optical signal reflect back and forth in the graphene layer 3 within the range of the Bragg resonant cavity 213, thereby enhancing the interaction between the optical signal and the graphene layer 3, thereby enabling the graphene layer 3 to absorb more photon energy. Similarly, the photocurrent formed by the photodetector can also be increased, further improving the photodetection responsivity of the photodetector.

[0038] Among them, the connection relationship between the first electrode and the second electrode and the positive and negative poles of the external electric field, respectively, and the magnitude of the voltage applied to the optical waveguide structure and the graphene layer through the first electrode and the second electrode can be set according to the change requirements of the absorption coefficient of the graphene layer to the optical signal after the pressure is applied, and the actual needs. In addition, because the first type of carriers and the second type of carriers are separated and directed under the action of the external electric field, and the first type of carriers are derived through the first electrode, and the second type of carriers are derived through the second electrode, the electrical properties of the first carriers and the second carriers can be determined according to the connection relationship between the first electrode and the second electrode and the positive and negative poles of the external electric field. For example: when the first electrode is electrically connected to the positive pole of the external electric field, and the second electrode is used to electrically connect the negative pole of the external electric field, the first type of carrier is a hole, and the first electrode is used to derive the hole. The second type of carrier is an electron, and the second electrode is used to derive the electron. For another example, when the first electrode is electrically connected to the negative pole of the external electric field, and the second electrode is used to electrically connect the positive pole of the external electric field, the first type of carriers are electrons, and the first electrode is used to extract electrons. The second type of carriers are holes, and the second electrode is used to extract holes.

[0039] From the above content, it can be known that the photodetector provided in the embodiment of the present invention can localize the transmitted optical signal into the graphene layer through the slit waveguide portion. At the same time, the Bragg resonant cavity provided at the slit waveguide portion can make the optical signal reflect back and forth in the graphene layer within the range of the Bragg resonant cavity, thereby enhancing the interaction between the optical signal and the graphene layer, thereby improving the photoelectric detection responsiveness of the photodetector during operation and improving the working performance of the photodetector.

[0040] In one example, if Figure 1 and Figure 2 As shown, along the extension direction of the slot waveguide portion 21, a plurality of periodically distributed adjustment structures are provided on the slot waveguide portion 21. Each adjustment structure includes a plurality of adjustment slots 214 that penetrate the slot waveguide portion 21 along the thickness direction of the slot waveguide portion 21 and are arranged at intervals. The Bragg resonant cavity 213 is a portion of the slot waveguide portion 21 where the slot slots 212 are located between adjacent adjustment structures.

[0041] Specifically, the number of periods of the above-mentioned adjustment structure can be set according to the requirements for the photoelectric detection responsiveness, the magnitude of the voltage applied to the first electrode and the second electrode, and the actual needs, and is not specifically limited here. It can be imagined that, as mentioned above, the Bragg resonant cavity can make the light signal reflect back and forth in the graphene layer within the range of the Bragg resonant cavity, so that the photon energy of the light signal can be fully absorbed by the graphene layer to form a larger photocurrent. In addition, the Bragg resonant cavity is the part of the slit groove of the slit waveguide part located between adjacent adjustment structures. Therefore, when other factors are the same, the larger the number of periods of the adjustment structure, the more Bragg resonant cavities are set on the slit waveguide part. Correspondingly, the efficiency of the light signal reflecting back and forth in the Bragg resonant cavity is higher, which can make the graphene layer absorb more photon energy, so that the photodetector forms a larger photocurrent, further improving the photoelectric detection responsiveness of the photodetector.

[0042] Specifically, the number of adjustment slots included in each adjustment structure, as well as the shape and specifications of the adjustment slots can be set according to actual needs. Exemplarily, the sizes of the multiple adjustment slots included in each adjustment structure, and the spacing between adjacent adjustment slots in the same adjustment structure meet the Bragg reflection condition at the corresponding wavelength of the optical signal. Specifically, the formula of the Bragg reflection condition is: Among them, Figure 2As shown, L1 is the length of the adjustment groove 214. Real(neff1) is the real part of the effective refractive index of the slot waveguide portion 21 located at the slot groove 212. L2 is the spacing between adjacent adjustment grooves 214. Real(neff2) is the real part of the effective refractive index of the slot waveguide portion 21 located at the adjustment groove 214. m is the reflection order. λ is the wavelength of the optical signal. Specifically, the specific value of the above-mentioned Real(neff1) is related to the width G1 of the slot groove 212, the width of the slot waveguide portion 21, and the height of the slot waveguide portion 21. For example, when the width of the slot waveguide portion 21 is 500nm and the height of the slot waveguide portion 21 is 220nm, when the width G1 of the slot groove 212 is 100nm, the value of Real (neff1) is 1.5131; when the width G1 of the slot groove 212 is 120nm, the value of Real (neff1) is 1.4541; when the width G1 of the slot groove 212 is 150, the value of Real (neff1) is 1.3930. The above-mentioned value of Real (neff1) can be obtained by simulation calculation under the corresponding width G1 of the slot groove 212, the width of the slot waveguide portion 21, and the height of the slot waveguide portion 21. Similarly, the specific value of Real (neff2) is related to the width G2 of the adjustment groove 214, the width of the slot waveguide portion 21, and the height of the slot waveguide portion 21. The method for determining the specific value of Real(neff2) can refer to the method for determining Real(neff1), which will not be repeated here. Based on this, in actual application, the wavelength corresponding to the optical signal to be detected is a known quantity. At this time, the size of the above parameters can be determined by setting some values ​​in L1, L2, Real(neff1) and Real(neff2) and calculating the remaining values ​​according to actual needs.

[0043] In addition, since the Bragg resonant cavity is a portion of the slot waveguide portion where the slot groove is located between adjacent adjustment structures, the Bragg resonant cavity determines the spacing between adjacent adjustment structures. The cavity length L of the Bragg resonant cavity can be calculated according to the formula Determine. Wherein, λ is the wavelength of the optical signal. neff1 is the effective refractive index of the slit waveguide located at the slit groove. In practical applications, the wavelength corresponding to the optical signal to be detected is a known quantity. The method for determining the specific value of neff1 can refer to the previous text. Based on this, when λ and neff1 are known, the cavity length L of the Bragg resonant cavity can be calculated according to the above formula.

[0044] In the actual application process, Figure 2In the slot waveguide portion 21 shown, the adjustment structure located on the left side of the Bragg resonant cavity 213 is the first adjustment structure, and the adjustment structure located on the right side of the Bragg resonant cavity 213 is the second adjustment structure. When the optical signal is transmitted to the first adjustment structure, part of the optical signal that meets the Bragg reflection condition is reflected back, and another part of the optical signal can be transmitted by the first adjustment structure into the Bragg resonant cavity 213 and continue to be transmitted forward. After being transmitted to the second adjustment structure, the optical signal that meets the corresponding Bragg reflection condition will be reflected back into the Bragg resonant cavity 213 by the second adjustment structure, and this part of the optical signal will interfere with the optical signal that has re-transmitted through the first adjustment structure. Based on this, the optical signal is reflected back and forth in the Bragg resonant cavity 213, so that the optical signal is transmitted back and forth in the graphene layer 3 within the range of the Bragg resonant cavity 213, thereby enhancing the interaction between the optical signal and the graphene layer 3 and increasing the effective length of the interaction between the optical signal and the graphene layer 3.

[0045] In one example, if Figure 2 As shown, each of the above-mentioned adjustment grooves 214 can be symmetrical about the central axis of the slit groove 212. In this case, when each of the adjustment grooves 214 is symmetrical about the central axis of the slit groove 212, the distribution of the adjustment structure in the slit waveguide portion 21 is more regular, which is conducive to the manufacture of the photodetector provided by the embodiment of the present invention.

[0046] Of course, the above adjustment grooves may not be symmetrical about the central axis of the slit groove. Specifically, the upper and lower distribution of each adjustment groove about the central axis of the slit groove can be set according to actual needs, as long as the Bragg reflection condition at the corresponding wavelength of the optical signal to be detected can be met.

[0047] In one example, if Figure 2 As shown, the adjustment groove 214 may be a rectangular adjustment groove 214 with arc chamfers.

[0048] It should be understood that when manufacturing photodetectors, a relatively mature CMOS process is usually used to improve the manufacturing yield of photodetectors. Based on this, in the actual manufacturing process of the photodetector provided by the embodiment of the present invention, when the theoretically designed adjustment groove is a rectangular adjustment groove, after the adjustment groove is etched on the slit waveguide portion using photolithography and etching processes, due to the existence of manufacturing errors, the actual adjustment groove is a rectangular adjustment groove with an arc chamfer, resulting in a deviation between the theoretically designed structure and the actual manufactured structure, and further making the size of the adjustment groove unable to fully meet the Bragg reflection conditions at the wavelength corresponding to the optical signal, resulting in poor working performance of the photodetector. Figure 2As shown, when the theoretically designed adjustment groove 214 is a rectangular adjustment groove 214 with an arc chamfer, the morphology of the adjustment groove 214 obtained after photolithography and etching is basically consistent with the morphology of the theoretically designed adjustment groove 214, so that the adjustment groove 214 obtained in both the theoretical design and actual manufacturing satisfies the Bragg reflection condition at the corresponding wavelength of the optical signal, thereby preventing the manufacturing accuracy of the photodetector from being affected by the existence of manufacturing errors and improving the working performance of the photodetector.

[0049] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0050] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A photoelectric detector, characterized in that: include: Base, An optical waveguide structure is formed on the substrate; the optical waveguide structure comprises a slit waveguide portion provided with a Bragg resonant cavity; along the extension direction of the slit waveguide portion, the slit waveguide portion is provided with a plurality of adjustment structures which are periodically distributed; each of the adjustment structures comprises a plurality of adjustment grooves which penetrate the slit waveguide portion along the thickness direction of the slit waveguide portion and are arranged at intervals; the Bragg resonant cavity is a portion of the slit groove of the slit waveguide portion which is located between adjacent adjustment structures; a graphene layer covering at least the slot waveguide portion, wherein the graphene layer fills a slot groove of the slot waveguide portion; The slit waveguide portion is used to localize the optical signal into the graphene layer; and a first electrode and a second electrode formed on the substrate; the first electrode is electrically connected to the optical waveguide structure and is used to guide the first type of carriers under the action of an external electric field; The second electrode is electrically connected to the graphene layer and is used to guide the second type of carriers under the action of the external electric field; the electrical properties of the first type of carriers and the second type of carriers are opposite.

2. The photodetector according to claim 1, characterized in that: The sizes of the multiple adjustment grooves included in each of the adjustment structures and the spacing between adjacent adjustment grooves in the same adjustment structure meet the Bragg reflection condition at a wavelength corresponding to the optical signal.

3. The photodetector according to claim 1, characterized in that: Each of the adjustment grooves is symmetrical about the central axis of the slit groove.

4. The photodetector according to claim 1, characterized in that: The adjusting groove is a rectangular adjusting groove with arc chamfers.

5. The photodetector according to claim 1, characterized in that: The thickness of the graphene layer is greater than or equal to the height of the slot waveguide portion.

6. The photodetector according to claim 1, characterized in that: The optical waveguide structure further includes a connecting portion formed on the substrate; the first electrode is electrically connected to the slot waveguide portion through the connecting portion.

7. The photodetector according to claim 1, characterized in that: The first electrode and the second electrode are both made of gold, copper or aluminum.

8. The photodetector according to claim 1, characterized in that: The slot waveguide portion has at least two strip waveguides and a slot groove located between adjacent strip waveguides.

9. The photoelectric detector according to any one of claims 1 to 8, characterized in that: The base is a silicon-based substrate; and / or the optical waveguide structure is made of silicon.

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