Ultra-compact near-infrared circularly polarized photoelectric detector and preparation method thereof

Abstract

The invention discloses an ultra-compact near-infrared circularly polarized photoelectric detector, which comprises an upper metal electrode plating layer, a lower metal electrode plating layer, a semiconductor substrate, a hexagonal close packing array substrate and a chiral super-surface layer, and can realize rapid and high-responsivity near-infrared circular polarization dependent light detection, and light signals can be directly converted into visible electric signals under zero bias voltage; different photoelectric signal conversion effects can be generated from different directions under irradiation of light with different wavelengths, and reference is provided for preparation of a multi-mode near-infrared circularly polarized photoelectric detector. The invention also discloses a preparation method of the ultra-compact near-infrared circularly polarized photoelectric detector, the preparation method is simple and convenient, the cost is relatively low, batch preparation can be realized, and the produced ultra-compact near-infrared circularly polarized photoelectric detector has the characteristics of high light absorbance, quick response and ultrahigh integration level.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared circular polarization response optoelectronic devices, and particularly relates to a super-compact near-infrared circular polarization photodetector and a preparation method thereof. Background Art

[0002] Efficient near-infrared detection of circularly polarized light provides highly technically attractive elements for next-generation quantum information, model encryption, remote sensing, imaging, etc. However, traditional near-infrared circular polarization detectors usually require the installation of external optical elements (linear polarizer plus quarter-wave plate), which makes it challenging to achieve integrated and flexible devices. In addition, due to the absorption, reflection, and scattering losses of the polarizer, part of the light energy is lost. The absorption of light by the polarizer material itself also causes part of the light energy to be lost, greatly reducing the utilization rate of light.

[0003] Near-infrared circularly polarized light can penetrate biological tissues, providing high-contrast imaging, which can be used for early disease diagnosis, labeling and detection of specific biomolecules, facilitating drug development and chemical synthesis, etc. At the same time, it can also be used to study the optical properties and structural characteristics of materials. In the synthesis and application of nanomaterials, near-infrared circularly polarized light can provide important optical information. However, near-infrared circular polarization light detection devices are usually complex and expensive, and the responsivity, response speed, device stability, etc. are all limited by technology.

[0004] Plasmonic nanostructures can generate high-energy "hot" electrons from light in a broadband manner according to their shape, size, and arrangement. Such structures have broad applications in photodetectors, enabling high-speed, broadband, and multi-color light detection. Since they operate without bandgap absorption, photon detection at any energy is possible through the engineering of plasmonic nanostructures. To obtain a controllable optoelectronic signal conversion device, current research mostly uses top-down lithography methods to fabricate plasmonic metasurfaces, but lithography is usually limited by high cost, cumbersome steps, and difficulty in large-scale production. And nano-lithography usually requires specific photoresist and substrate materials, and the selection and compatibility of these materials will affect the final pattern quality and function. Therefore, there is an urgent need to develop non-lithography methods to fabricate controllable plasmonic metasurface integrated near-infrared circular polarization photodetectors. Summary of the Invention

[0005] Based on the technical problems existing in the background art, the present invention proposes a super-compact near-infrared circular polarization photodetector and a preparation method thereof.

[0006] A super-compact near-infrared circular polarization photodetector proposed by the present invention includes

[0007] Upper and lower layers of metal electrode coatings;

[0008] Semiconductor substrate;

[0009] Hexagonal close-packed array substrate;

[0010] Chiral metasurface layer.

[0011] Preferably, the metal electrode coating is one or more of indium electrode coating, ITO electrode coating, and aluminum electrode coating.

[0012] Preferably, the semiconductor substrate is an n-type semiconductor that can form a Schottky potential with a metal.

[0013] Preferably, the hexagonal close-packed array substrate is an ordered array substrate obtained by assembling micro-nano scale polymer spheres into a single-layer hexagonal close-packed structure.

[0014] Preferably, the chiral metasurface layer is a metal and adhesion layer that can form a metal-semiconductor Schottky potential with silicon.

[0015] Preferably, a preparation method of an ultra-compact near-infrared circularly polarized photodetector includes the following steps:

[0016] S1. Select an n-type semiconductor that can form a Schottky potential with a metal as the semiconductor substrate for standby;

[0017] S2. By the method of self-assembly at the water-air interface, drop a water-phase suspension of hydrophobic polymer spheres with a certain concentration into water. Driven by the hydrophobic effect, surface tension and the interaction between microspheres, the hydrophobic polymer spheres with micro-nano scale self-assemble into a hexagonal close-packed array substrate with a single-layer hexagonal close-packed structure at the interface;

[0018] S3. Treat the semiconductor substrate by pickling and plasma methods to improve its hydrophilicity. Immerse the semiconductor substrate underwater and slowly lift it at a certain inclination angle. The hydrophobic polymer spheres with micro-nano scale are picked up with the semiconductor substrate, so that the hexagonal close-packed array substrate is transferred onto the semiconductor substrate;

[0019] S4. Anneal to make the array arrangement of the self-assembled hexagonal close-packed array substrate more regular;

[0020] S5. Adjust the array gap of the hexagonal close-packed array substrate by etching method;

[0021] S6. Through asymmetric metal deposition, form a chiral metasurface with an asymmetric metal coating on the hexagonal close-packed array substrate, thereby obtaining a metal-semiconductor Schottky diode, and capable of converting an optical signal into an electrical signal under zero bias voltage;

[0022] S7. Coat or spray a conductive material on both sides of the metal-semiconductor Schottky diode to form a metal electrode coating, which facilitates connecting the electrodes to detect the optical signal, thereby completing the entire preparation process of the ultra-compact near-infrared circularly polarized photodetector.

[0023] Preferably, in step S2, the size of the polymer spheres is 0.05 - 5 μm, the annealing temperature is 30 - 100 °C, and the concentration of the polymer sphere suspension is 0.2 - 20 wt%.

[0024] Preferably, in step S3, the inclination angle is 0 - 90°; in step S4, the annealing conditions are: annealing temperature: 30 °C - 200 °C; annealing time: 0.5 - 3 h.

[0025] Preferably, in step S5, the etching method used includes one or more of chemical etching method and physical etching method.

[0026] Preferably, in step S6, for the asymmetric metal deposition, the deposition angle is 0 - 90°, the coating thickness is 5 - 2000 nm, the number of coating layers is ≥1, the interlayer angle is ≥0°, and the deposition rate is

[0027] The beneficial effects of the present invention are as follows:

[0028] (1) For an ultra-compact near-infrared circularly polarized photodetector of the present invention, through the ultra-compact near-infrared circularly polarized photodetector based on a hexagonal close-packed array substrate, it can achieve fast and highly responsive near-infrared circular polarization-dependent light detection, and the optical signal can be directly converted into a visible electrical signal under zero bias voltage; different photoelectric signal conversion effects will be generated when irradiated with light from different directions and using different wavelengths, providing a reference for the preparation of multi-modal near-infrared circularly polarized photodetector devices.

[0029] (2) The preparation method of an ultra-compact near-infrared circularly polarized photodetector of the present invention overcomes the technical barriers in the prior art that the preparation of chiral metasurfaces is limited by high lithography costs, and near-infrared circularly polarized photodetectors rely on external polarization devices and it is difficult to achieve ultra-compact integration. The preparation method is simple and has a low cost, can achieve batch preparation, and the produced ultra-compact near-infrared circularly polarized photodetectors have the characteristics of high light absorption, fast response, and ultra-high integration. Description of the Drawings

[0030] Figure 1 : It is the structural hierarchy diagram of the ultra-compact near-infrared circularly polarized photodetector prepared by the present invention;

[0031] Figure 2 : It is the photograph of the ultra-compact near-infrared circularly polarized photodetector prepared by the present invention;

[0032] Figure 3 : This is an optical photograph of chiral and achiral devices observed in the reflection mode of a polarizing microscope when the two linear polarizers form an angle of 0° and 90° respectively for the present invention;

[0033] Figure 4 : This is the extinction spectrum of the chiral metasurface layer of the present invention in the visible-near infrared region;

[0034] Figure 5 : This is the circular dichroism absorption spectrum and the calculated response g-factor diagram of the chiral metasurface layer of the present invention in the visible-near infrared region;

[0035] Figure 6 : This is the adjustable g-factor diagram of the chiral signal in the near infrared region of the chiral metasurface layer of the present invention under different etching parameters;

[0036] Figure 7 : This is the dark current-photocurrent response signal diagram of the near infrared circular polarization response photodetector of the present invention under near infrared light illumination;

[0037] Figure 8 : This is the photocurrent response effect diagram of the front incident and back incident light under different near infrared wavelength illuminations of the present invention;

[0038] Figure 9 : This is the polarized photocurrent response of the device of the present invention under 940nm near infrared light illumination. Circular / elliptical polarized light is obtained using a linear polarizer and a quarter-wave plate. The figure shows the polarized response photocurrent signal obtained when the linear polarizer and the quarter-wave plate form an angle of 0 - 360° (the angle increases by 15° each time measurement). Detailed implementation mode

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0040] Embodiment 1:

[0041] Figure 1 This is the structural hierarchy diagram of the ultra-compact near infrared circular polarization photodetector prepared for the present invention. As Figure 1 shown, an ultra-compact near infrared circular polarization photodetector proposed by the present invention includes:

[0042] Upper and lower metal electrode coatings, which are one or more of indium electrode coating, ITO electrode coating, aluminum electrode coating, silver electrode coating, etc.;

[0043] Semiconductor substrate, which is an n-type semiconductor that can form a Schottky potential with the metal;

[0044] A hexagonal close-packed array substrate, which is an ordered array substrate obtained by assembling micro-nano scale polymer spheres into a single-layer hexagonal close-packed structure;

[0045] A chiral metasurface layer, a metal and an adhesion layer that can form a metal-semiconductor Schottky potential with silicon.

[0046] A preparation method of an ultra-compact near-infrared circularly polarized photodetector, comprising the following steps:

[0047] S1. Select an n-type semiconductor that can form a Schottky potential with a metal as a semiconductor substrate for standby.

[0048] S2. By the method of self-assembly at the water-air interface, a water-phase suspension of hydrophobic polymer spheres with a certain concentration is dropped into water. Driven by the hydrophobic effect, surface tension and the interaction between microspheres, the micro-nano scale hydrophobic polymer spheres self-assemble into a hexagonal close-packed array substrate with a single-layer hexagonal close-packed structure at the interface.

[0049] The size of the polymer spheres is 0.05 - 5 μm, and the concentration of the polymer sphere suspension is 0.2 - 20 wt%.

[0050] S3. Treat the semiconductor substrate by pickling and plasma methods to improve its hydrophilicity. Immerse the semiconductor substrate underwater and slowly lift it at a certain inclination angle (the inclination angle is 0 - 90°). The micro-nano scale hydrophobic polymer spheres are picked up with the semiconductor substrate, so that the hexagonal close-packed array substrate is transferred onto the semiconductor substrate.

[0051] S4. Anneal to make the array arrangement of the self-assembled hexagonal close-packed array substrate more regular. The annealing conditions are specifically: annealing temperature: 30°C - 200°C; annealing time: 0.5 - 3 h.

[0052] S5. Adjust the array gap of the hexagonal close-packed array substrate by etching methods. The etching methods include one or more of chemical etching methods and physical etching methods.

[0053] S6. Through asymmetric metal deposition, form a chiral metasurface with an asymmetric metal coating on the hexagonal close-packed array substrate, thereby obtaining a metal-semiconductor Schottky diode, which can convert an optical signal into an electrical signal under zero bias voltage.

[0054] Asymmetric metal deposition, the deposition angle is 0 - 90°, the coating thickness is 5 - 2000 nm, the number of coating layers is ≥1, the interlayer angle is ≥0°, and the deposition rate is The prepared metal-semiconductor Schottky diode has strong chiral optical activity, can convert an optical signal into an electrical signal under zero bias voltage, and has circular polarization-dependent absorption and reflection of near-infrared light. The obtained photodetector has circularly polarized photoelectric response.

[0055] S7. Coat or spray the conductive material on both sides of the metal-semiconductor Schottky diode to form a metal electrode coating, which is convenient for connecting the electrodes to detect the optical signal, thus completing the entire preparation process of the ultra-compact near-infrared circularly polarized photodetector.

[0056] Figure 2 This is the optical photograph of the ultra-compact near-infrared circularly polarized photodetector prepared by the present invention. As Figure 2 shown, the device exhibits different structural colors at different angles.

[0057] Figure 3 These are the optical photographs of the chiral device and the achiral device observed in the reflection mode of a polarizing microscope with two linear polarizers at angles of 0° and 90° respectively. As Figure 3 shown, the chiral metasurface has optical activity, while the achiral metasurface has no optical activity.

[0058] Figure 4 This is the extinction spectrum of the chiral metasurface in the visible-near-infrared region. As can be seen from Figure 4 , the plasmonic chiral metasurface has strong light absorption ability in the wide visible-near-infrared band.

[0059] Figure 5 This is the circular dichroism absorption spectrum and the calculated response g-factor diagram of the chiral metasurface in the visible-near-infrared region. As Figure 5 shown, the CD spectrum shows that the chiral metasurface has different absorption abilities for left-handed circularly polarized light and right-handed circularly polarized light, and the asymmetry factor reaches 10 -1 .

[0060] Figure 6 This is the adjustable g-factor diagram of the chiral signal in the near-infrared region of the chiral metasurface after etching the substrate with different sizes or different etching parameters. As Figure 6 shown, by adjusting the etching parameters of the self-assembled micro-nano substrate, a chiral metasurface with adjustable circular dichroism in the near-infrared region can be obtained.

[0061] Figures 7 - 9 This is the signal schematic diagram of the photocurrent of the ultra-compact near-infrared circularly polarized photodetector of the present invention under near-infrared light excitation. Figure 7 This is the photocurrent response in the alternating state of adding light illumination / removing light illumination. As can be seen from Figure 7 , the ultra-compact near-infrared circularly polarized photodetector has high responsivity and fast response speed. Figure 8 This is the photocurrent response effect diagram of the ultra-compact near-infrared circularly polarized photodetector with different wavelengths of near-infrared light incident from different directions. As can be seen from Figure 8 , changing the incident wavelength or the incident light direction can achieve different photocurrent responses, providing a reference for the design of multimodal photodetectors.Figure 9 The polarization photocurrent response of the device under 940 nm near-infrared light illumination. Circular / elliptical polarized light is obtained using a linear polarizer and a quarter-wave plate. The figure shows the polarization response photocurrent signal obtained when the linear polarizer and the quarter-wave plate form an angle of 0 - 360° (the angle increases by 15° each time). It can be seen from Figure 9 that the photocurrent response of the device has obvious polarization dependence.

[0062] A super-compact near-infrared circularly polarized photodetector of the present invention. The chiral metal metasurface layer of this photodetector, as a light absorption-thermoelectron emission layer, has high light absorption, improves the photoelectric responsivity, and realizes the detection of circularly polarized light in the super-compact integrated near-infrared region of the device. Due to the size controllability of the hexagonal close-packed array substrate of the self-assembled micro-nano substrate and the deposition controllability of the metal coating, the photoelectric response region of the device is adjustable in the visible-near-infrared region. By adjusting appropriate technical parameters, the photodetector can have circular polarization-dependent photoelectric response in the wide near-infrared band region.

[0063] A super-compact near-infrared circularly polarized photodetector of the present invention can realize fast and highly responsive near-infrared circular polarization-dependent light detection through a super-compact near-infrared circularly polarized photodetector based on a hexagonal close-packed array substrate. The optical signal can be directly converted into a visible electrical signal at zero bias voltage; different photoelectric signal conversion effects will be produced when irradiated with light from different directions and using different wavelengths, providing a reference for the preparation of multi-modal near-infrared circularly polarized photodetector devices.

[0064] A preparation method of a super-compact near-infrared circularly polarized photodetector of the present invention overcomes the technical barriers in the prior art that the preparation of chiral metasurfaces is limited by high lithography costs, and near-infrared circularly polarized photodetectors rely on external polarization devices and it is difficult to achieve super-compact integration. The preparation method is simple and has low cost, can realize batch preparation, and the produced super-compact near-infrared circularly polarized photodetectors have the characteristics of high light absorption, fast response, and ultra-high integration.

[0065] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. An ultra-compact near-infrared circularly polarized photodetector, characterized in that: include Upper and lower metal electrode coatings; Semiconductor substrate; Hexagonal close-packed array substrate; Chiral supersurface layer.

2. The ultra-compact near-infrared circularly polarized photodetector according to claim 1, characterized in that: The metal electrode coating is one or more of an indium electrode coating, an ITO electrode coating, an aluminum electrode coating, and a silver electrode coating.

3. The ultra-compact near-infrared circularly polarized photodetector according to claim 1, characterized in that: The semiconductor substrate is an n-type semiconductor that can form a Schottky potential with metal.

4. The ultra-compact near-infrared circularly polarized photodetector according to claim 1, characterized in that: The hexagonal close-packed array substrate is an ordered array substrate obtained by assembling micro-nano-scale polymer balls into a single-layer hexagonal close-packed structure.

5. The ultra-compact near-infrared circularly polarized photodetector according to claim 1, characterized in that: The chiral super surface layer is a metal and adhesion layer, which can form a metal-semiconductor Schottky potential with silicon.

6. A method for preparing an ultra-compact near-infrared circularly polarized photodetector according to any one of claims 1 to 5, characterized in that: The steps include: S1, select an n-type semiconductor that can form a Schottky potential with a metal as a semiconductor substrate for standby use; S2. By using the water-air interface self-assembly method, a certain concentration of micro-nano-scale hydrophobic polymer sphere aqueous suspension is dropped into water. Driven by the hydrophobic effect, surface tension and interaction between microspheres, the micro-nano-scale hydrophobic polymer spheres self-assemble at the interface into a hexagonal close-packed array substrate with a single-layer hexagonal close-packed structure; S3, treating the semiconductor substrate by acid washing and plasma to improve its hydrophilicity, extending the semiconductor substrate underwater, and slowly lifting it up at a certain tilt angle, so that the micro-nano-scale hydrophobic polymer balls are picked up along with the semiconductor substrate, so that the hexagonal close-packed array substrate is transferred to the semiconductor substrate; S4, making the array arrangement of the self-assembled hexagonal close-packed array substrate more regular by annealing; S5, adjusting the array gap of the hexagonal close-packed array substrate by an etching method; S6. Forming a chiral metasurface with an asymmetric metal coating on a hexagonal close-packed array substrate by asymmetric metal deposition, thereby obtaining a metal-semiconductor Schottky diode capable of converting an optical signal into an electrical signal under zero bias voltage; S7. Coat or spray the conductive material on both sides of the metal-semiconductor Schottky diode to form a metal electrode coating, which is convenient for connecting the electrodes to detect the light signal, thereby completing the entire preparation process of the ultra-compact near-infrared circularly polarized photodetector.

7. The method for preparing an ultra-compact near-infrared circularly polarized photodetector according to claim 6, characterized in that: In step S2, the size of the polymer spheres is 0.05-5 μm, and the concentration of the polymer sphere suspension is 0.2-20 wt%.

8. The method for preparing an ultra-compact near-infrared circularly polarized photodetector according to claim 6, characterized in that: In step S3, the tilt angle is 0-90°; in step S4, the annealing conditions are: annealing temperature: 30°C-200°C; annealing time: 0.5-3h.

9. The method for preparing an ultra-compact near-infrared circularly polarized photodetector according to claim 6, characterized in that: In step S5, the adopted etching method includes one or more of chemical etching method and physical etching method.

10. The method for preparing an ultra-compact near-infrared circularly polarized photodetector according to claim 6, characterized in that: In step S6, the asymmetric metal deposition has a deposition angle of 0-90°, a coating thickness of 5-2000 nm, a coating number of ≥1, an interlayer angle of ≥0°, and a deposition rate of

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