WO2016106731A1 - 一种石墨烯槽波导光探测器 - Google Patents

一种石墨烯槽波导光探测器 Download PDF

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Publication number
WO2016106731A1
WO2016106731A1 PCT/CN2014/096021 CN2014096021W WO2016106731A1 WO 2016106731 A1 WO2016106731 A1 WO 2016106731A1 CN 2014096021 W CN2014096021 W CN 2014096021W WO 2016106731 A1 WO2016106731 A1 WO 2016106731A1
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layer
graphene
groove
layers
core
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PCT/CN2014/096021
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English (en)
French (fr)
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王志仁
刘磊
邓舒鹏
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华为技术有限公司
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Priority to CN201480081823.XA priority Critical patent/CN106688108B/zh
Priority to PCT/CN2014/096021 priority patent/WO2016106731A1/zh
Publication of WO2016106731A1 publication Critical patent/WO2016106731A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation

Definitions

  • the present invention relates to the field of optoelectronic technology, and in particular, to a graphene slot waveguide photodetector.
  • Optical devices made of the novel material graphene are increasingly used in the communication band.
  • Graphene has unique physical properties such as its ability to absorb light in the visible to mid-infrared region and its ultra-high electron mobility due to its unique two-dimensional structural properties and linear electron energy dispersion.
  • FIG. 1 a schematic diagram of a structure of a graphene waveguide photodetector which has been studied is shown in FIG. 1
  • FIG. 2 an optical mode simulation diagram using the graphene waveguide photodetector for detecting.
  • incident light is propagated in a graphene waveguide photodetector with silicon (chemical symbol: Si) as a core layer and fused silica (SiO 2 ) as a lower cladding layer (English: cladding). Since the graphene is disposed on the core layer, when the incident light enters the waveguide (the core layer and the jacket layer form the waveguide, wherein the jacket layer includes the lower jacket layer), when the optical mode is formed, as shown in FIG.
  • silicon chemical symbol: Si
  • SiO 2 fused silica
  • the graphene is from the optical mode.
  • the evanescent field absorbs photons and converts them into carriers, which generate a current signal through the gold (chemical symbol: Au) electrode, thereby measuring the detection response of the graphene waveguide photodetector to 0.1 A/W ( Ampere/Watt).
  • the detection responsivity and the photoelectric conversion efficiency of the graphene waveguide photodetector are both proportional to the electric field strength of the optical mode of the region where the graphene is located, when the graphene waveguide photodetector of the above structure is used, as shown in FIG. 2 As shown, since the region where graphene is located is the evanescent field of the optical mode (the electric field strength of the evanescent field is low), the electric field intensity of the optical mode of the region where graphene is located is low, resulting in the graphene waveguide photodetector. Both the detection responsiveness and its photoelectric conversion efficiency are low.
  • the invention provides a graphene slot waveguide photodetector, the graphene slot waveguide optical probe
  • the detector has higher detection responsivity and photoelectric conversion efficiency than ordinary graphene waveguide photodetectors.
  • the present invention provides a graphene trench waveguide photodetector comprising:
  • a groove layer disposed on the lower jacket layer between adjacent core layers, the number of the groove layers being greater than or equal to 1, the groove layer having a refractive index smaller than two cores adjacent to the groove layer The refractive index of the layer;
  • the graphene layer being in contact with at least one of the groove layers or the graphene layer being disposed in at least one of the groove layers, the graphite
  • the olefin layer is in contact with at least one of the two metal electrodes.
  • a non-conductive material or a semiconductor material is disposed in the groove layer.
  • the total energy of the component of the electric field direction perpendicular to the groove surface is greater than the total energy of the component of the electric field direction parallel to the groove surface, the groove surface being adjacent to the core layer and the groove layer Contact surfaces.
  • the graphene layer and the At least one of the trough layers is in contact with,
  • a polarization direction of the light is parallel to a horizontal plane of the lower jacket layer, and a horizontal plane of the lower jacket layer is at least one core layer of the at least two core layers a plane in contact with the lower jacket layer.
  • the graphene layer is disposed in at least one of the groove layers
  • a polarization direction of the light is perpendicular to a horizontal plane of the lower jacket layer, and a horizontal plane of the lower jacket layer is at least one of the at least two core layers A plane in which the core layer is in contact with the lower jacket layer.
  • Each of the at least two core layers comprises a plurality of sub-core layers, and/or
  • Each of the groove layers includes a plurality of sub-slot layers.
  • the materials of the plurality of sub-core layers are the same, or the materials of the plurality of sub-core layers are different;
  • the materials of the plurality of sub-groove layers are the same, or the materials of the plurality of sub-groove layers are different.
  • the graphene layer is in contact with at least one of all of the core layers adjacent to the graphene layer.
  • a separator layer is disposed between the graphene layer and all of the core layers adjacent to the graphene layer.
  • the refractive index of the lower jacket layer is less than the refractive index of all core layers in contact with the lower jacket layer rate.
  • the material of the lower jacket layer is a non-conductive material
  • the material of the at least two core layers is a semiconductor material or a non-conductive material.
  • the materials of the at least two core layers are the same, or the materials of the at least two core layers are different.
  • the graphene channel waveguide photodetector provided by the present invention has a groove layer between at least two core layers disposed at intervals, and the refractive index of the groove layer is smaller than the refractive index of the core layer, so when the graphene channel waveguide light When the detector performs light detection, the channel layer of the waveguide can be used to concentrate the electric field distribution of the optical mode formed by the light in the groove layer, thereby enhancing the interaction between the graphene layer and the light in the groove layer, thereby making the graphite
  • the electric field intensity of the optical mode of the region where the olefin layer is located is high, so that the graphene channel waveguide photodetector provided by the embodiment of the invention has high photoelectric conversion efficiency and high detection responsivity. That is, the graphene slot waveguide photodetector provided by the embodiment of the invention has higher photoelectric conversion efficiency and detection responsivity than the conventional graphene waveguide photodetector.
  • FIG. 1 is a schematic structural view of a graphene waveguide photodetector provided by the prior art
  • FIG. 2 is a simulation diagram of an optical mode detected by a graphene waveguide photodetector provided by the prior art
  • FIG. 3(a) is a schematic structural view 1 of a graphene slot waveguide photodetector according to an embodiment of the present invention
  • 3(b) is a schematic structural view 1 of another graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 4 is a partial structural schematic view showing a groove layer and a core layer in a graphene channel waveguide photodetector according to an embodiment of the present invention
  • FIG. 5 is a schematic diagram of electric field distribution of an optical mode of a slot waveguide of a graphene slot waveguide photodetector according to an embodiment of the present invention
  • FIG. 6 is a schematic diagram of electric field distribution of an optical mode of a slot waveguide of another graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 7 is a schematic diagram showing the internal structure of a core layer and a slot layer in another graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 8 is a schematic structural diagram of still another graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 9(a) is a partial structural diagram of a graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 9(b) is a partial structural diagram of another graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 9(c) is a partial transverse cross-sectional view of a graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 9(d) is a partial transverse cross-sectional view of another graphene slot waveguide photodetector according to an embodiment of the present invention.
  • FIG. 10(a) is a second schematic structural view of a graphene channel waveguide photodetector according to an embodiment of the present invention.
  • FIG. 10(b) is a second structural diagram of another graphene-slot waveguide photodetector according to an embodiment of the present invention.
  • the graphene slot waveguide photodetector provided by the embodiment of the invention includes a lower jacket layer; at least two core layers spaced apart from the lower jacket layer, at least one of the at least two core layers and the a lower cover layer contact; a groove layer disposed between the adjacent core layers on the lower cover layer, the number of the groove layers being greater than or equal to 1, the groove layer having a refractive index smaller than adjacent to the groove layer a refractive index of the two core layers; a graphene layer and two metal electrodes, the graphene layer being in contact with at least one of the groove layers or at least the graphene layer being disposed in the groove layer In one of the groove layers, the graphene layer is in contact with at least one of the two metal electrodes.
  • the graphene layer and the metal electrode in the graphene slot waveguide photodetector may have various designs.
  • the method thus provides a graphene-slot waveguide photodetector having a plurality of different structures.
  • the embodiments of the present invention for convenience of description, and to facilitate a clearer and more complete understanding of the technical solutions of the present invention, only a few examples are exemplified below.
  • an embodiment of the present invention provides a graphene slot waveguide photodetector 1, as shown in Figure 3 (a) and Figure 3 (b), the graphene slot waveguide photodetector 1 includes a lower jacket layer 10; At least two core layers 11 disposed on the lower jacket layer 10, at least one of the at least two core layers 11 being in contact with the lower jacket layer 10; disposed on the lower jacket layer 10 a groove layer 12 between adjacent core layers 11, the number of the groove layers 12 being greater than or equal to 1, the refractive index of the groove layer 12 being smaller than the refractive index of the two core layers 11 adjacent to the groove layer 12.
  • the graphene layer 13 being in contact with at least one of the groove layers 12 or the graphene layer 13 being disposed in at least one of the groove layers 12. In the trench layer, the graphene layer 13 is in contact with at least one of the two metal electrodes 14.
  • FIG. 3(a) when the graphene layer 13 is in contact with at least one of the groove layers 12, the schematic diagram of the graphene channel waveguide photodetector 1 provided by the embodiment of the present invention is as shown in FIG. 3(a).
  • Figure 3(a) is merely illustrative of a graphene layer 13 is in contact with the groove layer 12
  • Figure 3(b) when the graphene layer 13 is disposed in at least one of the groove layers 12, the structure of the graphene channel waveguide photodetector 1 provided by the embodiment of the present invention
  • the schematic is shown in Figure 3(b).
  • the electric field of the optical mode formed by the light entering the waveguide (the core layer, the groove layer and the jacket layer forming the waveguide, wherein the jacket layer includes the lower jacket layer) is mainly concentrated in the groove layer, and the graphene channel waveguide light detection
  • the detection responsiveness and photoelectric conversion efficiency of the device are both proportional to the electric field strength of the optical mode in the region where the graphene layer is located. Therefore, the graphene-slot waveguide photodetector shown in Fig.
  • the quasi-transverse magnetic waveguide waveguide photodetector has higher detection responsivity and photoelectric conversion efficiency than the quasi-transverse trough waveguide photodetector.
  • the graphene-slot waveguide photodetector shown in Fig. 3(b) has less light loss and the size of the groove layer than the graphene-slot waveguide photodetector shown in Fig. 3(a).
  • the graphene groove waveguide shown in Fig. 3 (b) Photodetectors also have lower accuracy requirements for the manufacturing process.
  • the size of the groove layer (that is, the width of the groove layer) is D1; and the graphene groove waveguide light detection shown in FIG. 3(b) In the device, the size of the groove layer (that is, the thickness of the groove layer) is D2.
  • the graphene-slot waveguide photodetector provided by the embodiment of the present invention has only three core layers 11 and two groove layers 12, and the graphene layer 13 and two.
  • the metal electrodes 14 are all contacted as an example for exemplary explanation.
  • the graphene-slot waveguide photodetector provided by the embodiment of the present invention is exemplarily illustrated by taking the graphene layer 13 in a trench layer 12 as an example.
  • the waveguide since the refractive index of the groove layer is smaller than the refractive index of the core layer, the waveguide (core layer, The trough layer and the jacket layer form a waveguide, wherein the jacket layer includes the lower jacket layer) the electric field distribution of the optical mode formed by the propagating light is mainly concentrated in the trough layer, thereby enhancing the interaction between the graphene layer and the light in the trough layer, The electric field intensity of the optical mode of the region where the graphene layer is located is relatively high, so that the graphene channel waveguide photodetector provided by the embodiment of the invention has higher photoelectric conversion efficiency than the ordinary graphene waveguide photodetector. High detection responsiveness.
  • the graphene channel waveguide photodetector provided by the embodiment of the invention has a groove layer between at least two core layers disposed at intervals, and the refractive index of the groove layer is smaller than the refractive index of the core layer, so when the graphene groove When the waveguide photodetector performs light detection, the channel layer of the waveguide can be used to concentrate the electric field distribution of the optical mode formed by the light in the groove layer, thereby enhancing the interaction between the graphene layer and the light in the groove layer, thereby The electric field intensity of the optical mode of the region where the graphene layer is located is relatively high, so that the graphene channel waveguide photodetector provided by the embodiment of the invention has high photoelectric conversion efficiency and high detection responsivity. That is, the graphene slot waveguide photodetector provided by the embodiment of the invention has higher photoelectric conversion efficiency and detection responsivity than the conventional graphene waveguide photodetector.
  • the groove layer 12 may be air, that is, no visible substance is disposed in the groove layer 12; or the groove layer 12 may be provided with a non-conductive material, for example, the groove layer 12 A silicon dioxide (symbol: SiO 2 ) or silicon nitride (symbol: SiN) may be provided; or, the trench layer 12 may be provided with a semiconductor material, for example, the trench layer 12 may be provided with Si or the like. .
  • FIG. 4 a schematic diagram of a partial structure of the trench layer 12 and the core layer 11 , wherein the electric field direction is perpendicular to the component of the trench surface 120 in the electric field of the optical mode formed in the trench layer 12 .
  • the total energy is greater than the total energy of the component of the electric field direction parallel to the groove surface, that is, the electric field of the optical mode formed in the groove layer 12, the direction of the component of most of the electric field (labeled Er in FIG. 4) is perpendicular to the groove surface 120.
  • the groove surface 120 is a contact surface of the adjacent core layer 11 and the groove layer 12.
  • FIG. 4 is only exemplified by a graphene slot waveguide photodetector as shown in FIG. 3( a ), for the slot layer of the graphene slot waveguide photodetector as shown in FIG. 3( b ). 12 and the arrangement of the core layer 11 and the graphene channel waveguide light shown in Fig. 3 (a)
  • the groove layer 12 of the detector is similar to the arrangement of the core layer 11, and will not be described again here.
  • the graphene slot waveguide photodetector 1 provided by the embodiment of the present invention, when the light enters the waveguide in the graphene slot waveguide photodetector 1 (the core layer, the groove layer and the sleeve layer form a waveguide, wherein the sleeve layer comprises the lower jacket layer
  • the carriers generated by the absorption of photons by graphene generate a current signal when flowing through the metal electrode, and the current signal is proportional to the electric field strength of the optical mode formed in the groove layer, and only the optical mode
  • the component of the electric field direction perpendicular to the groove surface is able to gain in the groove layer.
  • the direction of the component of most of the electric field is perpendicular to the groove surface, in the graphene-slot waveguide photodetector shown in FIG. 3(a), when the light propagates along the waveguide
  • the direction of polarization of the light ie, the direction of the component of most of the electric field in the electric field of the optical mode
  • the horizontal plane 100 of the lower jacket layer 10 is the at least two core layers a plane in contact with the lower jacket layer 10; in the graphene slot waveguide photodetector shown in Fig.
  • the polarization direction of the light i.e., the electric field of the optical mode is large
  • the direction of the component of the partial electric field is perpendicular to the horizontal plane 100 of the lower jacket layer 10, and the horizontal plane 100 of the lower jacket layer 10 is one of the at least two core layers 11 in contact with the lower jacket layer 10. The plane.
  • a Quasi-TE slot waveguide calculated by a finite element method is used for the graphene slot waveguide photodetector shown in FIG. 3(a) provided by an embodiment of the present invention.
  • the electric field distribution of the optical mode, wherein the quasi-transverse electric power means that the direction of the component of most of the electric field in the electric field of the optical mode is parallel to the waveguide plane (the waveguide plane is a plane parallel to the plane in contact with the core layer and the lower jacket layer).
  • the electric field distribution of the optical mode of the quasi-TM slot waveguide calculated by the FEM of the graphene slot waveguide photodetector shown in FIG. 3(b) provided by the embodiment of the present invention is Magnetic means that the direction of the component of most of the electric field in the electric field of the optical mode is perpendicular to the plane of the waveguide.
  • both the abscissa and the left ordinate in FIGS. 5 and 6 indicate the physical position of the graphene layer in the optical mode; the right ordinate in FIGS. 5 and 6 indicates the optical mode of the region where the graphene layer is located.
  • the electric field strength accounts for the ratio of the electric field strength of the entire optical mode.
  • the electric field of the optical mode is in the groove layer (the refraction of the groove layer)
  • the intensity of the component of the electric field perpendicular to the groove surface within the refractive index of the core layer adjacent to the groove layer is greater than that in the core layer (the refractive index of the core layer is greater than the refractive index of the groove layer adjacent to the core layer)
  • the intensity of the component of the electric field on the groove surface, that is, the electric field distribution of the optical mode can be concentrated in the groove layer (it can be understood that in the electric field of the optical mode formed in the groove layer, the component of the electric field direction perpendicular to the groove surface can obtain a gain) .
  • the graphene slot waveguide photodetector provided by the embodiment of the invention has higher photoelectric conversion efficiency and detection responsivity than the conventional graphene waveguide photodetector.
  • each of the groove layers 12 may have a size smaller than a size of each of the core layers adjacent to the groove layer;
  • Each of the trough layers 12 may also have a size equal to the size of each of the core layers adjacent to the trough layer; each of the trough layers 12 may also be larger in size than the trough layer The size of each core layer in the adjacent core layer.
  • the size of the groove layer is the width of the groove layer or the thickness of the groove layer; the size of the core layer is also the width of the core layer or the thickness of the core layer.
  • the size of the groove layer is the width of the groove layer, and the size of the core layer is also the width of the core layer; as shown in FIG. 3( b )
  • the size of the groove layer is the thickness of the groove layer, and the size of the core layer is also the thickness of the core layer.
  • the smaller the size of the core layer (the narrower the width or The thinner the thickness, the smaller the attenuation of light reaching the boundary of the groove in the core layer, and the easier the light will pass through the core layer to reach the groove layer.
  • the direction of the electric field is perpendicular to the surface of the groove surface.
  • the trough layer size (the narrower the width or the thinner the thickness), the smaller the attenuation of light in the trough layer, so that the superposition of the electric field strength of the optical mode in the trough layer is The larger the value, the higher the gain of the electric field in the electric field of the optical mode, the component of the electric field perpendicular to the surface of the groove.
  • the size of the core layer of the waveguide and the size of the slot layer can be designed according to actual needs, which is not limited by the present invention.
  • the size of the core layer of the graphene channel waveguide photodetector shown in FIG. 3( a ) may be: the width of the core layer 11 is 500 nanometers; the specific size of the groove layer may be The groove layer 12 has a width of 50 nm.
  • the size of the core layer of the graphene-slot waveguide photodetector shown in FIG. 3(b) may specifically be: the width of the core layer 11 is 500 nm; the specific size of the groove layer may be: The groove layer 12 has a thickness of 20 nm.
  • each of the at least two core layers 11 The layers each include a plurality of sub-core layers 110, and/or each of the trench layers 12 includes a plurality of sub-slot layers 121.
  • the structure of the graphene channel waveguide photodetector 1 shown in FIG. 7 can better concentrate the electric field distribution of the optical mode in the groove layer, thereby further enhancing the interaction between the graphene layer and the light in the groove layer, Better improve the photoelectric conversion efficiency and detection responsiveness of the photodetector.
  • FIG. 7 is only exemplified by a graphene-slot waveguide photodetector as shown in FIG. 3(b), for the core layer of the graphene-slot waveguide photodetector shown in FIG. 3(a).
  • the internal structure of the 11 and the groove layer 12 is similar to that of the core layer 11 and the groove layer 12 of the graphene channel waveguide photodetector shown in Fig. 3(b), and will not be described herein.
  • the materials of the plurality of sub-core layers constituting each core layer in the graphene-slot waveguide photodetector 1 shown in FIG. 7 may be the same or different, and may be specifically designed according to actual use requirements. No restrictions.
  • the materials of the plurality of sub-groove layers constituting each of the groove layers in the graphene-slot waveguide photodetector 1 shown in FIG. 7 may be the same or different, and may be designed according to actual use requirements, and the present invention does not limit.
  • the embodiment of the present invention further provides a graphene slot waveguide photodetector as shown in FIG. 8.
  • the components in the graphene-slot waveguide photodetector shown in FIG. 8 and the connection relationship therebetween are the graphene-slot waveguide photodetectors shown in FIGS. 3(a) and 3(b) above.
  • the components in the Figure and the connection relationship between them are similar.
  • the graphene layer 13 can be understood to be disposed in the trench layer 12.
  • the graphene layer 13 can be understood as being disposed in the first groove layer 122 in the groove layer 12, and can also be understood as a second groove disposed in the groove layer 12. In layer 123.
  • the graphene layer 13 is in contact with at least one of the core layers adjacent to the graphene layer 13.
  • the graphene layer 13 is in contact with all of the core layers adjacent to the graphene layer 13. As shown in FIG. 3(b), the graphene layer 13 is in contact with one of the core layers adjacent to the graphene layer 13. As shown in FIG. 8, the graphene layer 13 is in contact with one half of all core layers adjacent to the graphene layer 13.
  • the graphene layer 13 is adjacent to the graphene layer 13 A separation layer is disposed between the core layers.
  • FIGS. 9( a ), 9 ( b ), 9 ( c ), and 9 ( d ) the graphene layer 13 is disposed between all the core layers adjacent to the graphene layer 13 .
  • FIG. 9(a) is a graphene layer waveguide photodetector shown in FIG. 3(a) in which a graphene layer 13 and a separator layer 15 are provided between all core layers adjacent to the graphene layer 13 Schematic diagram of the local structure;
  • Figure 9 (b) is the graphene groove wave shown in Figure 3 (b)
  • a partial structural schematic view of the partition layer 15 is provided between the graphene layer 13 in the light guiding detector and all the core layers adjacent to the graphene layer 13.
  • Figure 9(c) is a partial transverse cross-sectional view corresponding to Figure 9(a);
  • Figure 9(d) is a partial transverse cross-sectional view corresponding to Figure 9(b).
  • the material of the spacer layer 15 in the embodiment of the present invention may be a semiconductor material or a non-conductive material.
  • the specific design can be designed according to actual use requirements, and the invention is not limited.
  • the graphene layer 13 is in contact with the core layer adjacent to the graphene layer 13 , and is compared between the graphene layer 13 and the core layer adjacent to the graphene layer 13 .
  • Providing a spacer layer simplifies the fabrication process of the graphene-slot waveguide photodetector and can save costs.
  • the graphene layer 13 is a semiconductor material, a separation layer is disposed between the graphene layer 13 and a core layer adjacent to the graphene layer 13 compared to the graphene layer. Contact with the core layer adjacent to the graphene layer 13 can prevent the graphene layer 13 from leaking to some extent.
  • the two metal electrodes 14 are Another metal electrode is in contact with at least one of the at least two core layers 11.
  • the core layer (which may be a semiconductor material such as silicon) can transfer the bias voltage of the metal electrode to the graphene layer. Thereby, a potential difference is formed between the two metal electrodes, thereby causing a current signal to be generated when the graphene layer absorbs carriers generated by photons flowing through the metal electrode.
  • the other metal electrode of the two metal electrodes 14 and the extension portion 110 of at least one of the at least two core layers 11 contact.
  • the extended portion 110 of the at least one core layer may be the same material as the at least one core layer, or the extended portion 110 of the at least one core layer may be a different material than the at least one core layer.
  • the design of the core layer and the groove layer of the graphene channel waveguide photodetector shown in (a) of FIG. 10 and the core layer and the groove layer of the graphene channel waveguide photodetector shown in FIG. 3(a) The design of the same is the same; the design of the core layer and the groove layer of the graphene channel waveguide photodetector shown in (b) of FIG. 10 above and the graphene channel waveguide photodetector shown in FIG. 3(b)
  • the design of the core layer and the groove layer are the same.
  • the graphene layer 13 may be in contact with the two metal electrodes 14 or may be combined with one of the two metal electrodes 14.
  • Metal electrode contact is not specifically limited in the present invention.
  • the refractive index of the lower jacket layer 10 is smaller than the refractive index of all the core layers 11 in contact with the lower jacket layer 10, so that most of the incident light can be refracted into the core layer 11 to improve the core layer.
  • the material of the metal electrode 14 may be a metal material such as gold (element symbol: Au).
  • the material of the lower jacket layer 10 is a non-conductive material or a non-metal material such as a semiconductor material; and the materials of the at least two core layers 11 are a semiconductor material or a non-conductive material.
  • the lower jacket layer 10 may be a non-conductive material such as SiO 2 ; the at least two core layers 11 may be materials such as Si or SiN; and the trench layer 12 may be a material such as SiO 2 or SiN.
  • the invention does not specifically limit this.
  • any two of the at least two core layers 11 may be the same material or different materials.
  • the two core layers of the at least two core layers 11 may be the same material or different materials, which is not specifically limited in the present invention.
  • the material of the lower jacket layer 10, the material and quantity of the at least two core layers 11, and the material and quantity of the trench layer 12 are merely exemplary.
  • the graphene channel waveguide light provided by the embodiment of the present invention The material and quantity of the lower jacket layer 10, the at least two core layers 11 and the groove layer 12 in the detector include, but are not limited to, the above-listed ones, and the specific design can be designed according to actual use requirements. The invention does not specifically limit this.
  • the graphene channel waveguide photodetector provided by the embodiment of the invention has a groove layer between at least two core layers disposed at intervals, and the refractive index of the groove layer is smaller than the refractive index of the core layer, so when the graphene groove When the waveguide photodetector performs light detection, the channel layer of the waveguide can be used to concentrate the electric field distribution of the optical mode formed by the light in the groove layer, thus enhancing The interaction between the graphene layer and the light in the trench layer, so that the electric field intensity of the optical mode of the region where the graphene layer is located is higher, and the graphene trench waveguide photodetector provided by the embodiment of the invention has higher photoelectricity. Conversion efficiency and high detection responsiveness. That is, the graphene slot waveguide photodetector provided by the embodiment of the invention has higher photoelectric conversion efficiency and detection responsivity than the conventional graphene waveguide photodetector.
  • the at least two core layers 11 and the groove layer 12 may be manufactured as follows:
  • a groove may be opened at a certain interval in the core layer, so that a structure in which the core layer and the groove layer are spaced apart may be formed.
  • the method of trenching in the core layer may first form a lithographic pattern by photolithography to protect the core layer to be retained, and then etch the trench layer by deep reactive ion etching, and then deposit the trench layer by deposition. The material is filled into the etched trench layer.
  • a core layer 11 is first formed on the lower jacket layer 10, and a groove layer 12 is deposited on the core layer 11, and then a core layer 11 is deposited on the groove layer 12. If the groove layer 12 is to be further added, a groove layer 12 is deposited on the last deposited core layer 11, and then a core layer 11 is deposited on the groove layer 12. Repeating the above steps in sequence may form a structure in which the at least two core layers 11 and the groove layer 12 are spaced apart, that is, the groove layer 12 is disposed between the adjacent two core layers 11.
  • the at least two core layers 11 and the groove layer 12 which are produced according to the manufacturing method provided in the above (1) are specifically as shown in FIG. 3(a) and FIG. 10(a); 2)
  • the at least two core layers 11 and the groove layer 12 produced by the provided manufacturing method are specifically as shown in FIGS. 3(b) and 10(b).
  • the manufacturing methods provided in the above (1) and (2) are merely exemplary examples, and the embodiments of the present invention include, but are not limited to, the manufacturing methods provided in the above (1) and (2), and other embodiments capable of fabricating the present invention can be made. Methods of providing a core layer and a channel layer in a graphene-slot waveguide photodetector are within the scope of the present invention.
  • the lower jacket layer 10 In the graphene channel waveguide photodetector provided by the embodiment of the present invention, the lower jacket layer 10, the graphene layer 13 and the two except the at least two core layers 11 and the trench layer 12
  • the method for fabricating the metal electrodes 14 is the same as the method for fabricating the lower jacket layer, the graphene layer and the two metal electrodes in the prior art, and the specific design structure of the lower jacket layer, the graphene layer and the two metal electrodes can be practical according to the actual The use of adaptive adjustments is not repeated here.
  • the disclosed product may have other internal structures.
  • the product embodiments described above are merely illustrative.
  • the various components and the connection relationship therebetween are merely an exemplary list, and are not limited to the structures described in the above embodiments, that is, specific
  • the actual implementation of the product can also be any other structure that satisfies the usage requirements.
  • the various components may be connected in electrical, mechanical or other form.

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Abstract

提供了一种石墨烯槽波导光探测器，该石墨烯槽波导光探测器相比于普通的石墨烯波导光探测器具有较高的探测响应度和光电转换效率。该石墨烯槽波导光探测器包括：下套层（10）；间隔设置于下套层（10）上的至少两个芯层（11），至少两个芯层（11）中的至少一个芯层（11）与下套层（10）接触；设置于下套层（10）上、各相邻芯层（11）之间的槽层（12），槽层（12）的数量大于等于1，槽层（12）的折射率均小于与该槽层（12）相邻的两个芯层（11）的折射率；石墨烯层（13）以及两个金属电极（14），石墨烯层（13）与槽层（12）中的至少一个槽层（12）接触或者石墨烯层（13）设置在槽层（12）中的至少一个槽层（12）中，石墨烯层（13）与两个金属电极（14）中的至少一个金属电极（14）接触。

Description

一种石墨烯槽波导光探测器 技术领域
本发明涉及光电技术领域，尤其涉及一种石墨烯槽波导光探测器。
背景技术
以新型材料石墨烯制作的光器件，例如石墨烯波导光探测器在通信波段中的应用越来越广泛。石墨烯因其具有的独特的二维结构特性和线性电子能量色散，使它具有独特的物理特性，例如在可见光至中红外线波段能够吸收光，以及具有超高电子迁移率等。
目前，人们研究出的石墨烯波导光探测器的一种结构示意图如图1所示，利用该石墨烯波导光探测器进行探测的光模(英文：optical mode)仿真图为图2所示。图1中，入射光在以硅(化学符号：Si)为芯层，以熔融石英(英文：fused silica/SiO2)为下套层(英文：cladding)的石墨烯波导光探测器中传播。由于石墨烯设置在芯层上，因此当入射光进入波导(芯层和套层形成波导，其中，套层包括下套层)中形成光模时，如图2所示，石墨烯从光模的渐逝场吸收光子并转换成载流子，该载流子通过金(化学符号：Au)电极流动产生电流信号，从而测得石墨烯波导光探测器的探测响应度为0.1A/W(安培/瓦特)。
然而，由于石墨烯波导光探测器的探测响应度和其光电转换效率均与石墨烯所在区域的光模的电场强度成正比，因此当采用上述结构的石墨烯波导光探测器时，如图2所示，由于石墨烯所在区域为光模的渐逝场(渐逝场的电场强度较低)，因此石墨烯所在区域的光模的电场强度较低，从而导致该石墨烯波导光探测器的探测响应度和其光电转换效率均较低。
发明内容
本发明提供一种石墨烯槽波导光探测器，该石墨烯槽波导光探 测器相比于普通的石墨烯波导光探测器具有较高的探测响应度和光电转换效率。
为达到上述目的，本发明采用如下技术方案：
第一方面，本发明提供一种石墨烯槽波导光探测器，包括：
下套层；
间隔设置于所述下套层上的至少两个芯层，所述至少两个芯层中的至少一个芯层与所述下套层接触；
设置于所述下套层上、各相邻芯层之间的槽层，所述槽层的数量大于等于1，所述槽层的折射率均小于与所述槽层相邻的两个芯层的折射率；
石墨烯层，以及两个金属电极，所述石墨烯层与所述槽层中的至少一个槽层接触或者所述石墨烯层设置在所述槽层中的至少一个槽层中，所述石墨烯层与所述两个金属电极中的至少一个金属电极接触。
在第一方面的第一种可能的实现方式中，
所述槽层中为空气；或者
所述槽层中设置有非导电材料或半导体材料。
结合第一方面或第一方面的第一种可能的实现方式，在第二种可能的实现方式中，
所述槽层内的光模的电场中，电场方向垂直于槽面的分量的总能量大于电场方向平行于槽面的分量的总能量，所述槽面为相邻的芯层和槽层的接触面。
结合第一方面或第一方面的第一种可能的实现方式至第二种可能的实现方式中的任一种实现方式，在第三种可能的实现方式中，所述石墨烯层与所述槽层中的至少一个槽层接触，
当光沿所述至少两个芯层传播时，所述光的偏振方向与所述下套层的水平面平行，所述下套层的水平面为所述至少两个芯层中的至少一个芯层与所述下套层接触的平面。
结合第一方面或第一方面的第一种可能的实现方式至第二种可 能的实现方式中的任一种实现方式，在第四种可能的实现方式中，所述石墨烯层设置在所述槽层中的至少一个槽层中，
当光沿所述至少两个芯层传播时，所述光的偏振方向与所述下套层的水平面垂直，所述下套层的水平面为所述所述至少两个芯层中的至少一个芯层与所述下套层接触的平面。
结合第一方面或第一方面的第一种可能的实现方式至第四种可能的实现方式中的任一种实现方式，在第五种可能的实现方式中，
所述至少两个芯层中的每个芯层均包含多个子芯层，和/或
所述槽层中的每个槽层均包含多个子槽层。
结合第一方面的第五种可能的实现方式，在第六种可能的实现方式中，
所述多个子芯层的材料相同，或者所述多个子芯层的材料不同；
所述多个子槽层的材料相同，或者所述多个子槽层的材料不同。
结合第一方面或第一方面的第一种可能的实现方式至第六种可能的实现方式中的任一种实现方式，在第七种可能的实现方式中，
所述石墨烯层与和所述石墨烯层相邻的全部芯层中的至少一个芯层接触。
结合第一方面或第一方面的第一种可能的实现方式至第七种可能的实现方式中的任一种实现方式，在第八种可能的实现方式中，
所述石墨烯层与和所述石墨烯层相邻的全部芯层之间均设置有分隔层。
结合第一方面或第一方面的第一种可能的实现方式至第八种可能的实现方式中的任一种实现方式，在第九种可能的实现方式中，
当所述石墨烯层与所述两个金属电极中的一个金属电极接触时，所述两个金属电极中的另一个金属电极与所述至少两个芯层中的至少一个芯层的延伸部分接触。
结合第一方面或第一方面的第一种可能的实现方式至第九种可能的实现方式中的任一种实现方式，在第十种可能的实现方式中，
所述下套层的折射率小于与所述下套层接触的全部芯层的折射 率。
结合第一方面或第一方面的第一种可能的实现方式至第十种可能的实现方式中的任一种实现方式，在第十一种可能的实现方式中，
所述下套层的材料为非导电材料；
所述至少两个芯层的材料为半导体材料或者非导电材料。
结合第一方面或第一方面的第一种可能的实现方式至第十一种可能的实现方式中的任一种实现方式，在第十二种可能的实现方式中，
所述至少两个芯层的材料相同，或者所述至少两个芯层的材料不同。
本发明提供的石墨烯槽波导光探测器，由于在间隔设置的至少两个芯层之间设置了槽层，且槽层的折射率小于芯层的折射率，因此当该石墨烯槽波导光探测器进行光探测时，可以利用波导的槽层将光形成的光模的电场分布集中在槽层内，这样一来，增强了石墨烯层与槽层内的光的交互作用，从而使得石墨烯层所在区域的光模的电场强度较高，进而使得本发明实施例提供的石墨烯槽波导光探测器具有较高的光电转换效率和较高的探测响应度。即本发明实施例提供的石墨烯槽波导光探测器，相比于普通的石墨烯波导光探测器具有较高的光电转换效率和探测响应度。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本发明的其他实施例不再一一列举。
图1为现有技术提供的石墨烯波导光探测器的结构示意图；
图2为利用现有技术提供的石墨烯波导光探测器进行探测的光模仿真图；
图3(a)为本发明实施例提供的一种石墨烯槽波导光探测器的结构示意图一；
图3(b)为本发明实施例提供的另一种石墨烯槽波导光探测器的结构示意图一；
图4为本发明实施例提供的一种石墨烯槽波导光探测器中的槽层和芯层设置的局部结构示意图；
图5为本发明实施例提供的一种石墨烯槽波导光探测器的槽波导的光模的电场分布示意图；
图6为本发明实施例提供的另一种石墨烯槽波导光探测器的槽波导的光模的电场分布示意图；
图7为本发明实施例提供的另一种石墨烯槽波导光探测器中的芯层和槽层的内部结构示意图；
图8为本发明实施例提供的再一种石墨烯槽波导光探测器的结构示意图；
图9(a)为本发明实施例提供的一种石墨烯槽波导光探测器的局部结构示意图；
图9(b)为本发明实施例提供的另一种石墨烯槽波导光探测器的局部结构示意图；
图9(c)为本发明实施例提供的一种石墨烯槽波导光探测器的局部横向截面示意图；
图9(d)为本发明实施例提供的另一种石墨烯槽波导光探测器的局部横向截面示意图；
图10(a)为本发明实施例提供的一种石墨烯槽波导光探测器的结构示意图二；
图10(b)为本发明实施例提供的另一种石墨烯槽波导光探测器的结构示意图二。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明的一部分实施例，而不是全部的实施例。
需要说明的是：本发明实施例中所提及的“上”、“下”、“内” 及“外”等只是参考附图对本发明实施例进行说明，不作为限定用语。
本发明实施例提供的石墨烯槽波导光探测器包括下套层；间隔设置于所述下套层上的至少两个芯层，所述至少两个芯层中的至少一个芯层与所述下套层接触；设置于所述下套层上、各相邻芯层之间的槽层，所述槽层的数量大于等于1，所述槽层的折射率小于与所述槽层相邻的两个芯层的折射率；石墨烯层以及两个金属电极，所述石墨烯层与所述槽层中的至少一个槽层接触或者所述石墨烯层设置在所述槽层中的至少一个槽层中，所述石墨烯层与所述两个金属电极中的至少一个金属电极接触。
需要说明的是，本发明实施例中，具有上述描述的结构的石墨烯槽波导光探测器有多种，例如石墨烯槽波导光探测器中的石墨烯层和金属电极的设计可以有多种方法，从而可以得到具有多种不同结构的石墨烯槽波导光探测器。本发明实施例中，为了描述方便，而且便于更加清楚、完整地了解本发明的技术方案，以下仅以几种为例进行示例性的说明。
示例性的，本发明实施例提供一种石墨烯槽波导光探测器1，如图3(a)和图3(b)所示，该石墨烯槽波导光探测器1包括下套层10；间隔设置于所述下套层10上的至少两个芯层11，所述至少两个芯层11中的至少一个芯层与所述下套层10接触；设置于所述下套层10上、各相邻芯层11之间的槽层12，所述槽层12的数量大于等于1，所述槽层12的折射率小于与所述槽层12相邻的两个芯层11的折射率；石墨烯层13以及两个金属电极14，所述石墨烯层13与所述槽层12中的至少一个槽层接触或者所述石墨烯层13设置在所述槽层12中的至少一个槽层中，所述石墨烯层13与所述两个金属电极14中的至少一个金属电极接触。
具体的，当所述石墨烯层13与所述槽层12中的至少一个槽层接触时，本发明实施例提供的石墨烯槽波导光探测器1的结构示意图如图3(a)所示(其中，图3(a)仅是示例性的列举出石墨烯层 13与所述槽层12均接触)；当所述石墨烯层13设置在所述槽层12中的至少一个槽层中时，本发明实施例提供的石墨烯槽波导光探测器1的结构示意图如图3(b)所示。
进一步地，一方面，由于光进入波导(芯层、槽层和套层形成波导，其中套层包括下套层)形成的光模的电场主要集中在槽层内，且石墨烯槽波导光探测器的探测响应度和其光电转换效率均与石墨烯层所在区域的光模的电场强度成正比，因此，图3(b)所示的石墨烯槽波导光探测器(准横磁(英文：quasi transverse magnetic，缩写：quasi-TM)槽波导光探测器)与图3(a)所示的石墨烯槽波导光探测器(准横电(英文：quasi transverse electric，缩写：Quasi-TE)槽波导光探测器)相比，由于准横磁槽波导光探测器中的石墨烯层大部分都设置在槽层内，而准横电槽波导光探测器中的石墨烯层只与槽层接触(即设置在槽层边缘)，因此准横磁槽波导光探测器比准横电槽波导光探测器具有更高的探测响应度和光电转换效率。另一方面，图3(b)所示的石墨烯槽波导光探测器与图3(a)所示的石墨烯槽波导光探测器相比，光的损耗较小，而且在槽层的尺寸(图3(a)中槽层的尺寸为槽层的宽度，图3(b)中槽层的尺寸为槽层的厚度)相同的情况下，图3(b)所示的石墨烯槽波导光探测器对制作工艺的精度要求也较低。
其中，在图3(a)所示的石墨烯槽波导光探测器中，槽层的尺寸(即为槽层的宽度)为D1；在图3(b)所示的石墨烯槽波导光探测器中，槽层的尺寸(即为槽层的厚度)为D2。
上述图3(a)和图3(b)中，本发明实施例提供的石墨烯槽波导光探测器仅以芯层11为3个、槽层12为2个，以及石墨烯层13与两个金属电极14都接触为例进行示例性的说明。其中，图3(b)中，本发明实施例提供的石墨烯槽波导光探测器仅以石墨烯层13设置在一个槽层12中为例进行示例性的说明。
需要说明的是，本发明实施例提供的石墨烯槽波导光探测器中，由于槽层的折射率小于芯层的折射率，这样可将通过波导(芯层、 槽层和套层形成波导，其中套层包括下套层)传播的光形成的光模的电场分布主要集中在槽层内，从而可以增强石墨烯层与槽层内的光的交互作用，以使得石墨烯层所在区域的光模的电场强度较高，进而使得本发明实施例提供的石墨烯槽波导光探测器相比于普通的石墨烯波导光探测器具有较高的光电转换效率和较高的探测响应度。
本发明实施例提供的石墨烯槽波导光探测器，由于在间隔设置的至少两个芯层之间设置了槽层，且槽层的折射率小于芯层的折射率，因此当该石墨烯槽波导光探测器进行光探测时，可以利用波导的槽层将光形成的光模的电场分布集中在槽层内，这样一来，增强了石墨烯层与槽层内的光的交互作用，从而使得石墨烯层所在区域的光模的电场强度较高，进而使得本发明实施例提供的石墨烯槽波导光探测器具有较高的光电转换效率和较高的探测响应度。即本发明实施例提供的石墨烯槽波导光探测器，相比于普通的石墨烯波导光探测器具有较高的光电转换效率和探测响应度。
可选的，所述槽层12中可以为空气，即所述槽层12中不设置任何可见物质；或者，所述槽层12中也可以设置有非导电材料，例如所述槽层12中可以设置有二氧化硅(符号：SiO2)或者氮化硅(符号：SiN)等；或者，所述槽层12中也可以设置有半导体材料，例如所述槽层12中可以设置有Si等。
可选的，如图4所示，为槽层12与芯层11设置的局部结构示意图，其中，所述槽层12内形成的光模的电场中，电场方向垂直于槽面120的分量的总能量大于电场方向平行于槽面的分量的总能量，即所述槽层12内形成的光模的电场中，大部分电场的分量的方向(图4中标记为Er)垂直于槽面120。其中，所述槽面120为相邻的芯层11和槽层12的接触面。
其中，图4仅以如图3(a)所示的石墨烯槽波导光探测器为例进行示例性的说明，对于如图3(b)所示的石墨烯槽波导光探测器的槽层12与芯层11的设置结构与图3(a)所示的石墨烯槽波导光 探测器的槽层12与芯层11的设置结构类似，此处不再赘述。
本发明实施例提供的石墨烯槽波导光探测器1，当光进入该石墨烯槽波导光探测器1中的波导(芯层、槽层和套层形成波导，其中，套层包括下套层)时，光形成光模，石墨烯通过吸收光子产生的载流子在流经金属电极时产生电流信号，该电流信号与槽层内形成的光模的电场强度成正比，且只有光模的电场方向垂直于槽面的分量才能在槽层内得到增益。因此，为了使得槽层内的光模的电场中，大部分电场的分量的方向垂直于槽面，在如图3(a)所示的石墨烯槽波导光探测器中，当光沿波导传播时，光的偏振方向(即光模的电场中大部分电场的分量的方向)与所述下套层10的水平面100平行，所述下套层10的水平面100为所述至少两个芯层11与所述下套层10接触的平面；在如图3(b)所示的石墨烯槽波导光探测器中，当光沿波导传播时，光的偏振方向(即光模的电场中大部分电场的分量的方向)与所述下套层10的水平面100垂直，所述下套层10的水平面100为所述至少两个芯层11中的一个芯层与所述下套层10接触的平面。
如图5所示，为对本发明实施例提供的如图3(a)所示的石墨烯槽波导光探测器利用有限元分析(英文：finite element method，FEM)计算出的Quasi-TE槽波导的光模的电场分布，其中，准横电是指光模的电场中大部分电场的分量的方向平行于波导平面(波导平面为与芯层和下套层接触的平面平行的平面)。如图6所示，为对本发明实施例提供的如图3(b)所示的石墨烯槽波导光探测器利用FEM计算出的quasi-TM槽波导的光模的电场分布，其中，准横磁是指光模的电场中大部分电场的分量的方向垂直于波导平面。
需要说明的是，图5和图6中的横坐标和左纵坐标均表示石墨烯层在光模中的物理位置；图5和图6中的右纵坐标表示石墨烯层所在区域的光模的电场强度占整个光模的电场强度的比例。
可以看出，上述如图3(a)和3(b)中所示的石墨烯槽波导光探测器，虽然石墨烯仍然是在下套层的渐逝场吸收光的，但是光模 的电场分布却主要集中在槽层内，其物理原因是光模必须符合麦克斯韦方程组的边界条件。其中，麦克斯韦方程组的边界条件为：不同折射率的空间边界上，电场方向垂直于边界的分量的强度在两边要与其所在空间的折射率的平方成反比(而电场方向平行于边界的分量的强度均相等)。也就是说，当光模的偏振方向(即光的偏振方向，也即光模的大部分电场的分量的方向)垂直于槽面时，光模的电场中，处于槽层(槽层的折射率小于与槽层相邻的芯层的折射率)内垂直于槽面的电场的分量的强度大于处于芯层(芯层的折射率大于与芯层相邻的槽层的折射率)内垂直于槽面的电场的分量的强度，即光模的电场分布就能够集中在槽层内(可以理解为槽层内形成的光模的电场中，电场方向垂直于槽面的分量能够得到增益)。这样可以使得石墨烯层所在区域的光模的电场强度较高，从而增强了石墨烯层与槽层内的光的交互作用，进而提高了普通的石墨烯波导光探测器的光电转换效率和探测响应度。即本发明实施例提供的石墨烯槽波导光探测器，相比于普通的石墨烯波导光探测器具有较高的光电转换效率和探测响应度。
需要说明的是，本发明实施例提供的石墨烯槽波导光探测器1中，不限制槽层12的尺寸和芯层11的尺寸。具体的，本发明实施例提供的石墨烯槽波导光探测器1中，槽层12中的每个槽层的尺寸可以小于与该槽层相邻的芯层中的每个芯层的尺寸；槽层12中的每个槽层的尺寸也可以等于与该槽层相邻的芯层中的每个芯层的尺寸；槽层12中的每个槽层的尺寸还可以大于与该槽层相邻的芯层中的每个芯层的尺寸。
其中，上述槽层的尺寸为槽层的宽度或槽层的厚度；上述芯层的尺寸也为芯层的宽度或芯层的厚度。具体的，如图3(a)所示的石墨烯槽波导光探测器中，槽层的尺寸为槽层的宽度，芯层的尺寸也为芯层的宽度；如图3(b)所示的石墨烯槽波导光探测器中，槽层的尺寸为槽层的厚度，芯层的尺寸也为芯层的厚度。
进一步地，本发明实施例中，芯层的尺寸越小(宽度越窄或者 厚度越薄)，光在芯层中到达槽层边界的衰减就越小，光也就越容易穿过芯层到达槽层，这样，在光模的电场中，电场方向垂直于槽面的分量就能越集中在槽层内；槽层的尺寸越小(宽度越窄或者厚度越薄)，光在槽层中的衰减就越小，从而槽层中的光模的电场强度的叠加值就越大，这样，在光模的电场中，电场方向垂直于槽面的分量得到的增益就越高。
具体的，波导的芯层的尺寸和槽层的尺寸可根据实际需求进行设计，本发明对此不作限制。
举例来说，本发明实施例中如图3(a)所示的石墨烯槽波导光探测器的芯层的尺寸具体可以为：芯层11的宽度为500纳米；槽层的具体尺寸可以为：槽层12的宽度为50纳米。
又例如，本发明实施例中如图3(b)所示的石墨烯槽波导光探测器的芯层的尺寸具体可以为：芯层11的宽度为500纳米；槽层的具体尺寸可以为：槽层12的厚度为20纳米。
优选的，如图7所示，为芯层11和槽层12的内部结构示意图，本发明实施例提供的石墨烯槽波导光探测器中，所述至少两个芯层11中的每个芯层均包含多个子芯层110，和/或所述槽层12中的每个槽层均包含多个子槽层121。
如图7所示的石墨烯槽波导光探测器1的结构，能够更好地将光模的电场分布集中在槽层内，从而进一步增强石墨烯层与槽层内的光的交互作用，以更好地提高光探测器的光电转换效率和探测响应度。
其中，图7仅以如图3(b)所示的石墨烯槽波导光探测器为例进行示例性的说明，对于如图3(a)所示的石墨烯槽波导光探测器的芯层11和槽层12的内部结构与如图3(b)所示的石墨烯槽波导光探测器的芯层11和槽层12的内部结构类似，此处不再赘述。
可选的，如图7所示的石墨烯槽波导光探测器1中构成每个芯层的多个子芯层的材料可以相同，也可以不同，具体的可以根据实际使用需求进行设计，本发明不作限制。
相应的，如图7所示的石墨烯槽波导光探测器1中构成每个槽层的多个子槽层的材料可以相同，也可以不同，具体的可以根据实际使用需求进行设计，本发明不作限制。
可选的，在上述图3(a)和图3(b)的基础上，本发明实施例还提供一种如图8所示的石墨烯槽波导光探测器。具体的，如图8所示的石墨烯槽波导光探测器中的各个部件及其之间的连接关系与上述图3(a)和图3(b)所示的石墨烯槽波导光探测器中的各个部件及其之间的连接关系类似，具体的可参见对上述图3(a)和图3(b)所示的石墨烯槽波导光探测器中的各个部件及其之间的连接关系的描述，此处不再赘述。
其中，如图8所示的石墨烯槽波导光探测器中，所述石墨烯层13可以理解为设置在所述槽层12中。示例性的，在图8中，所述石墨烯层13可以理解为设置在所述槽层12中的第一槽层122中，也可以理解为设置在所述槽层12中的第二槽层123中。
可选的，如图3(a)、图3(b)和图8所示，所述石墨烯层13与和所述石墨烯层13相邻的全部芯层中的至少一个芯层接触。
具体的，如图3(a)所示，所述石墨烯层13与和所述石墨烯层13相邻的全部芯层均接触。如图3(b)所示，所述石墨烯层13与和所述石墨烯层13相邻的全部芯层中的一个芯层接触。如图8所示，所述石墨烯层13与和所述石墨烯层13相邻的全部芯层中的一半芯层接触。
可选的，在如图3(a)、图3(b)和图8所示的石墨烯槽波导光探测器中，所述石墨烯层13与和所述石墨烯层13相邻的全部芯层之间均设置有分隔层。如图9(a)、图9(b)、图9(c)和图9(d)所示，为石墨烯层13与和所述石墨烯层13相邻的全部芯层之间均设置有分隔层15的局部结构示意图。
其中，图9(a)为图3(a)所示的石墨烯槽波导光探测器中石墨烯层13与和所述石墨烯层13相邻的全部芯层之间均设置有分隔层15的局部结构示意图；图9(b)为图3(b)所示的石墨烯槽波 导光探测器中石墨烯层13与和所述石墨烯层13相邻的全部芯层之间均设置有分隔层15的局部结构示意图。图9(c)为与图9(a)对应的局部横向截面示意图；图9(d)为与图9(b)对应的局部横向截面示意图。
本发明实施例中的分隔层15的材料可以为半导体材料或者非导电材料。具体的可根据实际使用需求进行设计，本发明不作限制。
需要说明的是，所述石墨烯层13与和所述石墨烯层13相邻的芯层接触，相比于所述石墨烯层13与和所述石墨烯层13相邻的芯层之间设置有分隔层，能够简化石墨烯槽波导光探测器的制作工艺，且能够节省成本。相应的，由于所述石墨烯层13为半导体材料，因此，所述石墨烯层13与和所述石墨烯层13相邻的芯层之间设置有分隔层，相比于所述石墨烯层13与和所述石墨烯层13相邻的芯层接触，能够在一定程度上防止所述石墨烯层13漏电。
可选的，如图10(a)和图10(b)所示，当所述石墨烯层13与所述两个金属电极14中的一个金属电极接触时，所述两个金属电极14中的另一个金属电极与所述至少两个芯层11中的至少一个芯层接触。如图10(a)和图10(b)所示的石墨烯槽波导光探测器的结构中，芯层(可以为硅等半导体材料)能把金属电极的偏制电压传到石墨烯层周围，从而在两个金属电极之间形成电势差，进而使得石墨烯层吸收光子产生的载流子流经金属电极时形成电流信号。
具体的，如图10(a)和图10(b)所示，所述两个金属电极14中的另一个金属电极与所述至少两个芯层11中的至少一个芯层的延伸部分110接触。其中，至少一个芯层的延伸部分110可以与至少一个芯层为相同的材料，或者至少一个芯层的延伸部分110可以与至少一个芯层为不同的材料。
其中，上述图10中的(a)所示的石墨烯槽波导光探测器的芯层和槽层的设计与图3(a)所示的石墨烯槽波导光探测器的芯层和槽层的设计相同；上述图10中的(b)所示的石墨烯槽波导光探测器的芯层和槽层的设计与图3(b)所示的石墨烯槽波导光探测器的 芯层和槽层的设计相同。
需要说明的是，本发明实施例提供的石墨烯槽波导光探测器，所述石墨烯层13可以与所述两个金属电极14均接触，也可以与所述两个金属电极14中的一个金属电极接触，本发明对此不作具体限制。
可选的，所述下套层10的折射率小于与所述下套层10接触的全部芯层11的折射率，这样可以将大部分的入射光折射至芯层11内，以提高芯层11内的光的能量。
可选的，所述金属电极14的材料可以为金(元素符号：Au)等金属材料。
可选的，所述下套层10的材料为非导电材料或者半导体材料等非金属材料；所述至少两个芯层11的材料为半导体材料或者非导电材料。
示例性的，所述下套层10可以为SiO2等非导电材料；所述至少两个芯层11可以为Si或SiN等材料；所述槽层12可以为SiO2或SiN等材料，本发明对此不作具体限制。
其中，所述至少两个芯层11中的任意两个芯层可以为相同的材料，也可以为不同的材料。当所述槽层12的数量大于1时，所述至少两个芯层11中的任意两个芯层可以为相同的材料，也可以为不同的材料，本发明对此不作具体限制。
上述所述下套层10的材料、所述至少两个芯层11的材料和数量以及所述槽层12的材料和数量仅是示例性的列举，本发明实施例提供的石墨烯槽波导光探测器中的所述下套层10、所述至少两个芯层11以及所述槽层12的材料和数量包括但不限于上述列举的几种，具体的可根据实际使用需求进行设计，本发明对此不作具体限制。
本发明实施例提供的石墨烯槽波导光探测器，由于在间隔设置的至少两个芯层之间设置了槽层，且槽层的折射率小于芯层的折射率，因此当该石墨烯槽波导光探测器进行光探测时，可以利用波导的槽层将光形成的光模的电场分布集中在槽层内，这样一来，增强 了石墨烯层与槽层内的光的交互作用，从而使得石墨烯层所在区域的光模的电场强度较高，进而使得本发明实施例提供的石墨烯槽波导光探测器具有较高的光电转换效率和较高的探测响应度。即本发明实施例提供的石墨烯槽波导光探测器，相比于普通的石墨烯波导光探测器具有较高的光电转换效率和探测响应度。
需要说明的是，本发明实施例提供的石墨烯槽波导光探测器中，所述至少两个芯层11和所述槽层12的制作方法可以为下述的一种：
(1)在所述下套层10上先制作一层实体的芯层，并在该实体的芯层中按照设计要求依次开槽，以形成至少两个芯层11和槽层12间隔设置的结构，即槽层12设置在相邻的两个芯层11之间。
其中，可以在芯层中每间隔一定的间距就开一个槽，这样即可形成芯层和槽层间隔设置的结构。具体的，在芯层中开槽的方法可以先以光刻方式形成模版，以保护需要保留的芯层，然后使用深反应式离子蚀刻把槽层刻蚀出来，然后采用沉积的方法将槽层的材料填入刻蚀好的槽层内。
(2)在所述下套层10上先间隔制作一个芯层11，并在此芯层11上沉积一个槽层12，然后在此槽层12上沉积一个芯层11。如要再增加槽层12，则在最后一次沉积的芯层11上再沉积一个槽层12，然后在此槽层12上再沉积一个芯层11。依次重复以上步骤可以形成所述至少两个芯层11和槽层12间隔设置的结构，即槽层12设置在相邻的两个芯层11之间。
需要说明的是，按照上述(1)提供的制作方法制作出的所述至少两个芯层11和所述槽层12具体如图3(a)和图10(a)所示；按时上述(2)提供的制作方法制作出的所述至少两个芯层11和所述槽层12具体如图3(b)和图10(b)所示。
进一步地，上述(1)和(2)提供的制作方法仅是示例性的列举，本发明实施例包括但不限于上述(1)和(2)提供的制作方法，其他能够制作本发明实施例提供的石墨烯槽波导光探测器中的芯层和槽层的方法都在本发明的保护范围之内。
本发明实施例提供的石墨烯槽波导光探测器中，除所述至少两个芯层11和所述槽层12之外的所述下套层10、所述石墨烯层13和所述两个金属电极14的制作方法均与现有技术中制作下套层、石墨烯层和两个金属电极的方法相同，且下套层、石墨烯层和两个金属电极具体的设计结构可根据实际使用需要进行适应性的调整，此处不再赘述。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，仅以上述各模块的划分进行举例说明，实际应用中，可以根据需要而将上述产品的内部结构设计为满足使用需求的结构，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的产品，可以具有其它的内部结构。例如，以上所描述的产品实施例仅仅是示意性的，例如，各个部件及其之间的连接关系仅仅是一种示例性的列举，并不限于上述实施例描述的几种结构，即具体的产品的实际实现还可以为其他任意满足使用需求的结构。另一点，各个部件之间可以是以电性，机械或其它的形式连接。
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应所述以权利要求的保护范围为准。

Claims (13)

  1. 一种石墨烯槽波导光探测器，其特征在于，包括：
    下套层；
    间隔设置于所述下套层上的至少两个芯层，所述至少两个芯层中的至少一个芯层与所述下套层接触；
    设置于所述下套层上、各相邻芯层之间的槽层，所述槽层的数量大于等于1，所述槽层的折射率均小于与所述槽层相邻的两个芯层的折射率；
    石墨烯层，以及两个金属电极，所述石墨烯层与所述槽层中的至少一个槽层接触或者所述石墨烯层设置在所述槽层中的至少一个槽层中，所述石墨烯层与所述两个金属电极中的至少一个金属电极接触。
  2. 根据权利要求1所述的石墨烯槽波导光探测器，其特征在于，
    所述槽层中为空气；或者所述槽层中设置有非导电材料或半导体材料。
  3. 根据权利要求1或2所述的石墨烯槽波导光探测器，其特征在于，
    所述槽层内的光模的电场中，电场方向垂直于槽面的分量的总能量大于电场方向平行于槽面的分量的总能量，所述槽面为相邻的芯层和槽层的接触面。
  4. 根据权利要求1-3任一项所述的石墨烯槽波导光探测器，其特征在于，所述石墨烯层与所述槽层中的至少一个槽层接触，
    当光沿所述至少两个芯层传播时，所述光的偏振方向与所述下套层的水平面平行，所述下套层的水平面为所述至少两个芯层中的至少一个芯层与所述下套层接触的平面。
  5. 根据权利要求1-3任一项所述的石墨烯槽波导光探测器，其特征在于，所述石墨烯层设置在所述槽层中的至少一个槽层中，
    当光沿所述至少两个芯层传播时，所述光的偏振方向与所述下套层的水平面垂直，所述下套层的水平面为所述所述至少两个芯层中的 至少一个芯层与所述下套层接触的平面。
  6. 根据权利要求1-5任一项所述的石墨烯槽波导光探测器，其特征在于，
    所述至少两个芯层中的每个芯层均包含多个子芯层，和/或
    所述槽层中的每个槽层均包含多个子槽层。
  7. 根据权利要求6所述的石墨烯槽波导光探测器，其特征在于，
    所述多个子芯层的材料相同，或者所述多个子芯层的材料不同；
    所述多个子槽层的材料相同，或者所述多个子槽层的材料不同。
  8. 根据权利要求1-7任一项所述的石墨烯槽波导光探测器，其特征在于，
    所述石墨烯层与和所述石墨烯层相邻的全部芯层中的至少一个芯层接触。
  9. 根据权利要求1-7任一项所述的石墨烯槽波导光探测器，其特征在于，
    所述石墨烯层与和所述石墨烯层相邻的全部芯层之间均设置有分隔层。
  10. 根据权利要求1-9任一项所述的石墨烯槽波导光探测器，其特征在于，
    当所述石墨烯层与所述两个金属电极中的一个金属电极接触时，所述两个金属电极中的另一个金属电极与所述至少两个芯层中的至少一个芯层的延伸部分接触。
  11. 根据权利要求1-10任一项所述的石墨烯槽波导光探测器，其特征在于，
    所述下套层的折射率小于与所述下套层接触的全部芯层的折射率。
  12. 根据权利要求1-11任一项所述的石墨烯槽波导光探测器，其特征在于，
    所述下套层的材料为非导电材料或者半导体材料；
    所述至少两个芯层的材料为半导体材料或者非导电材料。
  13. 根据权利要求1-12任一项所述的石墨烯槽波导光探测器，其特征在于，
    所述至少两个芯层的材料相同，或者所述至少两个芯层的材料不同。
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