A room temperature wide-spectrum infrared detector based on moire superlattice

Abstract

The application relates to a room-temperature wide-spectrum infrared detector based on a moire superlattice, which comprises a silicon substrate, a TMDCs moire superlattice structure, a semi-metal moire superlattice structure, an AI2O3 structure and an electrode; wherein the TMDCs moire superlattice structure, the semi-metal moire superlattice structure and the AI2O3 structure are sequentially arranged in a direction away from the silicon substrate; the TMDCs moire superlattice structure is formed by N groups of repeated first heterojunctions, and the first heterojunctions are formed by twist stacking of different transition metal sulfides; the semi-metal moire superlattice structure is formed by N groups of repeated second heterojunctions, and the second heterojunctions are formed by twist stacking of a corner multi-layer Dirac semi-metal material and a corner multi-layer boron nitride. The application has the beneficial effect that the moire superlattice interlayer coupling formed by twist multi-layer Dirac semi-metals and corner multi-layer boron nitride realizes multiplication of mid-infrared photo-generated carriers.

Description

Technical Field

[0001] This invention belongs to the field of room temperature broadband detection technology, and particularly relates to a room temperature broadband infrared detector based on a moiré superlattice. Background Technology

[0002] Infrared light, as an electromagnetic wave, lies between visible light and microwaves and is generally approximated as near-infrared, mid-infrared, far-infrared, and very far-infrared. Infrared detectors rely on the photoelectric effect to convert incident infrared radiation into measurable electrical signals for infrared detection. They are mainly divided into photon detectors and thermal detectors. Photon detectors have advantages such as high quantum efficiency (photon energy directly excites charge carriers to generate electron-hole pairs), fast response speed (picosecond-level response time), support for multispectral detection, achieving spectral responses in different bands, and high signal-to-noise ratio, making them dominant in high-end applications. However, two-dimensional materials such as graphene and transition metal chalcogenides (TMDCs) are revolutionizing the design paradigm of traditional infrared detectors due to their unique electronic band structures, tunable band gaps, ultrafast responses, and heterojunction degrees of freedom.

[0003] Because of the low energy of photons in the mid- and far-infrared regions, the corresponding photoelectric signals are weak and easily drowned out by background noise in the circuit system, resulting in low detector sensitivity. This necessitates a large photosensitive area and reliance on low-temperature noise reduction techniques. Furthermore, due to the extremely wide infrared spectrum, the bandgap of semiconductor materials limits the coverage of the entire infrared band for a single detector, generally requiring the combined action of multiple different materials, complex device structures, and different operating mechanisms. Therefore, achieving high-sensitivity, ultrafast-response, full-infrared detection technology at room temperature remains a challenge. Two-dimensional materials with twisted corners and their stacked moiré superlattices can circumvent the constraints of traditional detection techniques and fabrication limitations. This invention aims to design a novel, high-performance, single-unit ultrafast photon-based infrared optical sensor capable of room-temperature full-infrared spectral detection based on this principle. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a room-temperature broadband infrared detector based on a moiré superlattice.

[0005] In the first aspect, a room temperature broadband infrared detector based on a moiré superlattice is provided, including: a silicon substrate, a TMDCs moiré superlattice structure, a half-metallic moiré superlattice structure, an Al2O3 structure, and electrodes;

[0006] The TMDCs moiré superlattice structure, the half-metal moiré superlattice structure, and the Al2O3 structure are sequentially arranged along the direction away from the silicon substrate. The TMDCs moiré superlattice structure is formed by N sets of repeating first heterojunctions, which are formed by twisted stacking of different transition metal sulfides. The half-metal moiré superlattice structure is formed by N sets of repeating second heterojunctions, which are formed by twisted stacking of corner multilayer Dirac half-metal materials and corner multilayer boron nitride.

[0007] Preferably, the transition metal sulfides include MoS2, MoS3, WSe2, WS2, WS3, FeS, FeS2, Cu2S, CuS, NiS, and NiS2.

[0008] Preferably, the Dirac semimetal material includes graphene.

[0009] Preferably, the electrodes are located on a silicon substrate, a TMDCs moiré superlattice structure, a half-metal moiré superlattice structure, and an Al2O3 structure, respectively; the electrode on the silicon substrate serves as the back gate, the electrode on the Al2O3 structure serves as the top gate, the electrode on the TMDCs moiré superlattice structure serves as the drain, and the electrode on the half-metal moiré superlattice structure serves as the source.

[0010] As a preferred method, the height of the Schottky barrier of the half-metallic moiré superlattice structure is controlled by the electrodes at the Al2O3 structure to adjust the Fermi level of the Dirac half-metal.

[0011] In a second aspect, a method for fabricating a room-temperature broadband infrared detector based on a moiré superlattice as described in any of the first aspects is provided, comprising:

[0012] Step 1: Provide a silicon substrate;

[0013] Step 2: Stack N sets of repeating first heterojunctions sequentially on the surface of a silicon substrate to form a TMDCs moiré superlattice structure;

[0014] Step 3: Stack N sets of repeating second heterojunctions sequentially on the TMDCs moiré superlattice structure to form a boron nitride-coated half-metallic moiré superlattice structure.

[0015] Step 4: Transfer the Al2O3 structure onto the semi-metallic moiré superlattice structure by mechanical exfoliation;

[0016] Step 5: Fabricate corresponding electrodes on the silicon substrate, the TMDCs moiré superlattice structure, the half-metal moiré superlattice structure, and the Al2O3 structure.

[0017] Preferably, in step 2, the first heterojunction is composed of MoS2 and WSe2; stacking the first heterojunction on the surface of the silicon substrate includes:

[0018] MoS2 is transferred to the surface of a silicon substrate by mechanical peeling.

[0019] WSe2 is transferred to MoS2 by mechanical stripping.

[0020] Preferably, in step 2, the transfer of MoS2 to the silicon substrate surface by mechanical peeling includes:

[0021] Take out an appropriate amount of MoS2 crystals and use blue film tape to peel off the MoS2 crystals layer by layer until the atomic thickness is reached.

[0022] The stripped MoS2 crystals are then transferred onto PDMS.

[0023] MoS2 crystals on PDMS are transferred to a silicon substrate using a transfer platform with the assistance of an optical microscope; the silicon substrate needs to be heated during the bonding process between PDMS and the silicon substrate.

[0024] The beneficial effects of this invention are:

[0025] 1. The Dirac semimetal material used in this invention has an adjustable Fermi level, and the Schottky barrier is controlled by the top gate, which significantly improves the responsivity to the near-infrared spectrum and enhances the near-infrared photocurrent.

[0026] 2. This invention achieves mid-infrared photogenerated carrier multiplication through interlayer coupling of a moiré superlattice formed by twisted multilayer Dirac half-metals and twisted multilayer boron nitride.

[0027] 3. This invention adjusts the twisted stacking of different transition metal sulfides through cornering and bottom gate adjustments, resulting in a TMDC (Transient Metal Dioxide Dismutase) heterojunction. S Moiré superlattices enable effective detection of far-infrared signals.

[0028] 4. This invention utilizes a Schottky quantum cascade device structure made of two-dimensional materials to realize a single infrared detector that integrates responses in four different infrared bands: near, mid, far, and extremely far, thereby achieving room temperature detection of the entire infrared spectrum. Attached Figure Description

[0029] Figure 1 A schematic diagram of the structure of a room-temperature broadband infrared detector based on a moiré superlattice provided by the present invention;

[0030] Figure 2 The graph showing the trend of external quantum conversion efficiency of twisted graphene as the number of layers increases, provided by the present invention;

[0031] Figure 3 A readout circuit diagram of a room-temperature broadband infrared detector based on a moiré superlattice is provided for this invention.

[0032] Figure labeling: Silicon substrate 1, TMDC S 1. Mohr superlattice structure 2. Semimetallic Mohr superlattice structure 3. First hexagonal boron nitride 4. First twisted multilayer graphene 5. Second hexagonal boron nitride 6. Second twisted multilayer graphene 7. Third hexagonal boron nitride 8. Third twisted multilayer graphene 9. Fourth hexagonal boron nitride 10. Al₂O₃ structure 11. First electrode structure 12. Second electrode structure 13. Third electrode structure 14. Fourth electrode structure 15. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0034] Example 1:

[0035] To address the problems of existing technologies, Embodiment 1 of this application provides a room-temperature broadband infrared detector based on a moiré superlattice, which introduces a twisted multilayer Dirac half-metal material. This twisted multilayer Dirac half-metal material exhibits extremely high responsivity to near-infrared light, and its Fermi level can be tuned by adjusting the gate voltage. Figure 2 As shown, this application provides a trend diagram of the external quantum conversion efficiency of the twisted multilayer Dirac half-metal material as the number of layers increases (taking graphene as an example). By changing the number of stacked layers of the twisted multilayer Dirac half-metal material, under the combined effect of various different carrier mechanisms of the repeating coating structure of the twisted multilayer Dirac half-metal material and the twisted multilayer boron nitride, the collection and conversion efficiency of the Schottky half-metal region of the device for infrared photogenerated carriers is improved. This provides feasibility support for the scheme of N repeating heterojunctions formed by twisted multilayer Dirac half-metal material and twisted multilayer boron nitride to form a half-metal moiré superlattice structure 3; in addition, as Figure 3 As shown, this application provides a readout circuit for a room-temperature broadband infrared detector based on a moiré superlattice. In the circuit, the infrared detector operates under a reverse bias voltage, causing photogenerated carriers to accelerate in the electric field, inducing an avalanche multiplication effect and generating a photocurrent. The circuit consists of operational amplifier A and feedback resistor R. f Compensation capacitor C f A three-part transimpedance amplifier converts the weak photocurrent generated by the infrared detector into a measurable output voltage V. out The room-temperature broadband infrared detector and readout circuit based on a moiré superlattice constitute a pixel with photoelectric conversion and signal amplification functions, which can be used for image sensing.

[0036] Specifically, such as Figure 1 As shown, the room temperature broadband infrared detector based on a moiré superlattice includes: a silicon substrate 1, a TMDCs moiré superlattice structure 2, a half-metallic moiré superlattice structure 3, an Al2O3 structure 11, and electrodes.

[0037] In this structure, a TMDCs moiré superlattice structure 2, a half-metallic moiré superlattice structure 3, and an Al2O3 structure 11 are sequentially arranged along a direction away from the silicon substrate 1. The TMDCs moiré superlattice structure 2 is formed by N sets of repeating first heterojunctions, which are formed by twisted stacking of different transition metal sulfides. The half-metallic moiré superlattice structure 3 is formed by N sets of repeating second heterojunctions, which are formed by twisted stacking of corner multilayer Dirac half-metal materials and corner multilayer boron nitride.

[0038] TMDC S The moiré superlattice structure 2 serves as the semiconductor region of the Schottky junction in the overall device, as well as the collection region for photogenerated carriers and the far-infrared photosensitive region, and is depleted by the half-metal region of the twisted multilayer graphene. TMDC S The torsion angle range of different transition metal sulfides in the Mohr superlattice structure 2 is not limited. These transition metal sulfides may include MoS2, MoS3, WSe2, WS2, WS3, FeS, FeS2, Cu2S, CuS, NiS, and NiS2. For example, ... Figure 1 As shown, the first heterojunction consists of MoS2 and WSe2. Furthermore, the number of layers for each different transition metal sulfide material is ≤10 layers, TMDC S The overall thickness of the Mohr superlattice structure 2 is ≤300μm.

[0039] The semi-metallic moiré superlattice structure 3 serves as the semi-metallic region of the Schottky junction in the overall device, as well as the photosensitive regions in the near-infrared, mid-infrared, and far-infrared regions. Furthermore, the torsion angle of the multilayer Dirac semi-metallic material is primarily a "magic angle." It should be noted that in condensed matter physics, when two Dirac semi-metallic films are stacked together with a specific small torsion angle, the interlayer coupling between them leads to a drastic reconstruction of the electronic band structure in the low-energy region due to the relative rotation of the momentum spaces of the Dirac cones in the two layers. At this specific torsion angle, the band structure near the Fermi surface becomes exceptionally flat (bandwidth significantly reduced), thereby greatly enhancing the importance of the Coulomb interaction between electrons relative to their kinetic energy. This specific torsion angle that leads to extreme band flattening is called the "magic angle" in Dirac semi-metals. In addition, other torsion angles are also included within the structural scope of this invention. The Dirac semi-metallic material includes graphene or other families of Dirac semi-metallic materials. Furthermore, the semi-metallic moiré superlattice structure 3 is a boron nitride-protected coating structure, which provides excellent protection for graphene and facilitates a clean interface effect between graphene and boron nitride. Specifically, the boron nitride is hexagonal boron nitride, structurally not limited to corner structures or ordinary stacked structures, and the graphene is specifically twisted multilayer graphene. In addition, the number of layers in the Dirac semi-metallic material is ≤100, the number of boron nitride layers is ≤20, and the overall thickness of the semi-metallic moiré superlattice structure 3 is ≤300 μm.

[0040] Furthermore, infrared detectors based on two-dimensional materials have clean interfaces at the atomic scale because the layers are in contact by van der Waals forces and there are no vertical dangling bonds.

[0041] Example 2:

[0042] Based on Example 1, Example 2 of this application provides a more specific room temperature broadband infrared detector based on a moiré superlattice, including: a silicon substrate 1, a TMDCs moiré superlattice structure 2, a half-metallic moiré superlattice structure 3, an Al2O3 structure 11, and electrodes.

[0043] In this structure, a TMDCs moiré superlattice structure 2, a half-metallic moiré superlattice structure 3, and an Al2O3 structure 11 are sequentially arranged along a direction away from the silicon substrate 1. The TMDCs moiré superlattice structure 2 is formed by N sets of repeating first heterojunctions, which are formed by twisted stacking of different transition metal sulfides. The half-metallic moiré superlattice structure 3 is formed by N sets of repeating second heterojunctions, which are formed by twisted stacking of corner multilayer Dirac half-metal materials and corner multilayer boron nitride.

[0044] Specifically, the electrodes are located on the silicon substrate 1, the TMDCs moiré superlattice structure 2, the half-metal moiré superlattice structure 3, and the Al2O3 structure 11, respectively. The electrode on the silicon substrate (i.e., the first electrode structure 12) serves as the back gate, the electrode on the Al2O3 structure 4 (i.e., the third electrode structure 14) serves as the top gate, the electrode on the TMDCs moiré superlattice structure 2 (i.e., the second electrode structure 13) serves as the drain, and the electrode on the half-metal moiré superlattice structure 3 (i.e., the fourth electrode structure 15) serves as the source.

[0045] The height of the Schottky barrier of the semimetallic moiré superlattice structure 3 is adjusted by controlling the electrode at structure 11 of Al2O3, thereby adjusting the Fermi level of the Dirac semimetal.

[0046] It should be noted that the parts in this embodiment that are the same as or similar to those in Embodiment 1 can be referred to each other, and will not be repeated in this application.

[0047] Example 3:

[0048] Based on Example 2, Example 3 of this application provides a method for fabricating a room-temperature broadband infrared detector based on a moiré superlattice, including:

[0049] Step 1: Provide a silicon substrate;

[0050] Step 2: Stack N sets of repeating first heterojunctions sequentially on the surface of a silicon substrate to form a TMDCs moiré superlattice structure.

[0051] In step 2, the first heterojunction is composed of MoS2 and WSe2; stacking the first heterojunction on the surface of the silicon substrate includes:

[0052] MoS2 is transferred to the surface of a silicon substrate by mechanical peeling.

[0053] WSe2 is transferred onto MoS2 by mechanical peeling, completing the stacking of a first set of heterojunctions. Then, the MoS2 of the next set of first heterojunctions is transferred onto the WSe2 surface of the previous set of first heterojunctions by mechanical peeling, and the above steps are repeated until all first heterojunctions are stacked.

[0054] In step 2, the transfer of MoS2 to the silicon substrate surface by mechanical peeling includes:

[0055] Take out an appropriate amount of MoS2 crystals and use blue film tape to peel off the MoS2 crystals layer by layer until the atomic thickness is reached.

[0056] The stripped MoS2 crystals are then transferred onto PDMS.

[0057] MoS2 crystals on PDMS are transferred to a silicon substrate using a transfer platform with the assistance of an optical microscope; the silicon substrate needs to be heated during the bonding process between PDMS and the silicon substrate.

[0058] Step 3: Stack N sets of repeating second heterojunctions sequentially on the TMDCs moiré superlattice structure to form a boron nitride-coated half-metallic moiré superlattice structure.

[0059] Specifically, similar to the method of stacking the first heterojunction in step 2, such as... Figure 1 As shown, the Multi-h-BN is first transferred to the WSe2 surface of the last group of first heterojunctions using a mechanical stripping method, and then the tBLG is transferred to the Multi-h-BN surface, completing the stacking of the first group of second heterojunctions. The subsequent stacking steps of the remaining second heterojunctions are not described in detail.

[0060] Step 4: Transfer the Al2O3 structure onto the semi-metallic moiré superlattice structure by mechanical stripping.

[0061] Step 5: Fabricate corresponding electrodes on the silicon substrate, the TMDCs moiré superlattice structure, the half-metal moiré superlattice structure, and the Al2O3 structure.

[0062] In step 5, the electrode fabrication steps specifically include: first, uniformly applying photoresist to the target area, then drawing the electrode pattern using a laser direct writing device, followed by development using a diluted developer, then depositing the metal of the electrode using a Sputter magnetron sputtering system, and finally stripping the remaining photoresist with an acetone solution until the electrode pattern is exposed.

[0063] In addition, other methods such as molecular beam epitaxy (MBE) and chemical vapor deposition (CVD) can be used to prepare room temperature broadband infrared detectors based on moiré superlattices.

[0064] It should be noted that the method provided in this embodiment is the method corresponding to the product provided in embodiment 2. Therefore, the parts that are the same as or similar to those in embodiment 2 in this embodiment can be referred to each other, and will not be repeated in this application.

Claims

1. A room-temperature broadband infrared detector based on a moiré superlattice, characterized in that, include: Silicon substrate, TMDCs moiré superlattice structure, semi-metallic moiré superlattice structure, Al2O3 structure and electrode; The TMDCs moiré superlattice structure, the half-metal moiré superlattice structure, and the Al2O3 structure are sequentially arranged along the direction away from the silicon substrate. The TMDCs moiré superlattice structure is formed by N sets of repeating first heterojunctions, which are formed by twisted stacking of different transition metal sulfides. The half-metal moiré superlattice structure is formed by N sets of repeating second heterojunctions, which are formed by twisted stacking of corner multilayer Dirac half-metal materials and corner multilayer boron nitride.

2. The room-temperature broadband infrared detector based on a moiré superlattice according to claim 1, characterized in that, The transition metal sulfides include MoS2, MoS3, WSe2, WS2, WS3, FeS, FeS2, Cu2S, CuS, NiS, and NiS2.

3. The room-temperature broadband infrared detector based on a moiré superlattice according to claim 2, characterized in that, The Dirac semimetal material includes graphene.

4. The room-temperature broadband infrared detector based on a moiré superlattice according to claim 3, characterized in that, The electrodes are located on a silicon substrate, a TMDCs moiré superlattice structure, a half-metal moiré superlattice structure, and an Al2O3 structure, respectively. The electrode on the silicon substrate serves as the back gate, the electrode on the Al2O3 structure serves as the top gate, the electrode on the TMDCs moiré superlattice structure serves as the drain, and the electrode on the half-metal moiré superlattice structure serves as the source.

5. The room-temperature broadband infrared detector based on a moiré superlattice according to claim 4, characterized in that, The height of the Schottky barrier in the half-metallic moiré superlattice structure can be modulated by adjusting the electrodes at the Al2O3 structure, thereby adjusting the Fermi level of the Dirac half-metal.

6. A method for fabricating a room-temperature broadband infrared detector based on a moiré superlattice as described in any one of claims 1 to 5, characterized in that, include: Step 1: Provide a silicon substrate; Step 2: Stack N sets of repeating first heterojunctions sequentially on the surface of a silicon substrate to form a TMDCs moiré superlattice structure; Step 3: Stack N sets of repeating second heterojunctions sequentially on the TMDCs moiré superlattice structure to form a boron nitride-coated half-metallic moiré superlattice structure. Step 4: Transfer the Al2O3 structure onto the semi-metallic moiré superlattice structure by mechanical exfoliation; Step 5: Fabricate corresponding electrodes on the silicon substrate, the TMDCs moiré superlattice structure, the half-metal moiré superlattice structure, and the Al2O3 structure.

7. The method for fabricating a room-temperature broadband infrared detector based on a moiré superlattice according to claim 6, characterized in that, In step 2, the first heterojunction is composed of MoS2 and WSe2; stacking the first heterojunction on the surface of the silicon substrate includes: MoS2 is transferred to the surface of a silicon substrate by mechanical peeling. WSe2 is transferred to MoS2 by mechanical stripping.

8. The method for fabricating a room-temperature broadband infrared detector based on a moiré superlattice according to claim 7, characterized in that, In step 2, the transfer of MoS2 to the silicon substrate surface by mechanical peeling includes: Take out an appropriate amount of MoS2 crystals and use blue film tape to peel off the MoS2 crystals layer by layer until the atomic thickness is reached. The stripped MoS2 crystals are then transferred onto PDMS. MoS2 crystals on PDMS are transferred to a silicon substrate using a transfer platform with the assistance of an optical microscope; the silicon substrate needs to be heated during the bonding process between PDMS and the silicon substrate.

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