Heterojunction polarized photoelectric detector based on anisotropic two-dimensional material and preparation method thereof

Abstract

The invention discloses a heterojunction polarized photoelectric detector based on an anisotropic two-dimensional material and a preparation method thereof, and relates to the technical field of photoelectric detectors. According to the technical scheme, the detector is characterized by comprising a substrate, anisotropic two-dimensional materials GaTe and PdSe2 prepared through a metal film auxiliary mechanical stripping method, a corner heterojunction formed by stacking through a fixed-point transfer technology and an electrode. The preparation method comprises the steps of preparing a material by a metal film auxiliary stripping method, forming a heterojunction by a fixed-point transfer technology and preparing an electrode. The polarization ratio and the photoelectric response performance of the detector are improved by optimizing material preparation, the cleanliness of the heterojunction interface and the torsion angle, and polarization detection in the ultraviolet-visible light-infrared full-wave band range is achieved. The invention has the advantages of simple process, low cost, excellent performance and the like, and is suitable for the field of polarized photoelectric detection.

Description

Technical Field

[0001] The present invention relates to the technical field of photodetectors, and more specifically, to a heterojunction polarization photodetector based on anisotropic two-dimensional materials and a preparation method thereof. Background Art

[0002] Polarization photodetectors have important applications in the fields of optical communication, imaging, remote sensing, etc. Traditional polarization photodetectors are based on bulk materials (such as silicon, germanium) or complex optical structures, and have problems such as large volume, high cost, and low polarization sensitivity. In recent years, two-dimensional materials have provided new possibilities for the development of high-performance polarization photodetectors due to their unique electrical, optical, and mechanical properties. In particular, novel anisotropic two-dimensional materials with low-symmetry crystal structures exhibit strong linear dichroism, can sensitively sense different polarization directions of incident light, and have the application potential of polarization-resolved optoelectronic devices. Although researchers have conducted a large number of studies on the preparation of anisotropic two-dimensional materials, anisotropic optoelectronic properties, and polarization photodetectors, etc., the preparation of anisotropic two-dimensional heterojunctions and the application of polarization optoelectronic devices are still in the initial stage of research. For example, problems such as small polarization ratio, low sensitivity, and narrow spectral range exist in anisotropic two-dimensional photodetectors, and the internal scientific problems of the influence of the heterojunction stacking angle on their polarization optoelectronic properties have not been revealed yet.

[0003] However, compared with the preparation of traditional isotropic two-dimensional materials, the preparation of anisotropic two-dimensional GaTe and PdSe 2 materials is relatively difficult. This is because the symmetry of the GaTe crystal structure is extremely low, and the dissociation energies in the directions of each crystal axis are inconsistent, while PdSe 2 has strong interlayer coupling between crystal layers, resulting in it being difficult to obtain large-area anisotropic two-dimensional materials by traditional mechanical exfoliation methods. Therefore, it is crucial to develop a method for preparing large-area anisotropic two-dimensional GaTe and PdSe 2 materials based on a metal film-assisted mechanical exfoliation method. In addition, although anisotropic two-dimensional GaTe and PdSe 2 photodetectors have been further improved in terms of miniaturization and polarization optoelectronic performance, due to the limitation of the intrinsic bandgap of a single two-dimensional GaTe material, problems such as low sensitivity and single optical response band of its photodetectors occur, especially the device sensitivity in the near-infrared band is low. Therefore, it is of great significance to develop a heterojunction polarization photodetector based on anisotropic two-dimensional materials and a preparation method thereof. Summary of the Invention

[0004] The object of the present invention is to provide a heterojunction polarization photodetector based on anisotropic two-dimensional materials and a preparation method thereof. By optimizing material preparation, the cleanliness of the heterojunction interface, and the twist angle, the polarization ratio and photoelectric response performance of the detector are improved, and polarization light detection in the full ultraviolet-visible-infrared wavelength range is achieved. The detector has the advantages of simple process, low cost, and excellent performance, and is applicable to the field of polarization photodetection.

[0005] The above technical object of the present invention is achieved through the following technical solutions: A heterojunction polarization photodetector based on anisotropic two-dimensional materials includes a substrate, anisotropic two-dimensional materials GaTe and PdSe2 prepared by a metal film-assisted mechanical exfoliation method, a twist angle heterojunction formed by stacking two-dimensional GaTe and PdSe2 through a fixed-point transfer technique, and metal electrodes for connecting the heterojunction and realizing photoelectric performance measurement.

[0006] The present invention is further provided that: The substrate is a silicon wafer, a silicon dioxide substrate, or a flexible substrate.

[0007] The present invention is further provided that: The thickness of the anisotropic two-dimensional materials GaTe and PdSe2 is 1-10 layers.

[0008] The present invention is further provided that: The twist angle range of the twist angle heterojunction is 0° to 60°.

[0009] The present invention is further provided that: The metal electrode material is gold (Au), chromium (Cr), or titanium (Ti), and the thickness is 10-100 nm.

[0010] The present invention further provides a preparation method for the above polarization photodetector, which specifically includes the following steps:

[0011] S1. Prepare anisotropic two-dimensional materials GaTe and PdSe2 by a metal film-assisted mechanical exfoliation method;

[0012] S2. Stack GaTe and PdSe2 through a fixed-point transfer technique to form a twist angle heterojunction;

[0013] S3. Prepare electrodes on the heterojunction, complete device preparation, and perform photoelectric performance testing.

[0014] Further, the metal film-assisted mechanical exfoliation method includes the following steps:

[0015] (1) Use tape to exfoliate single-layer or few-layer materials from bulk GaTe and PdSe2 crystals;

[0016] (2) Transfer the exfoliated materials to a target substrate coated with a metal film, and the thickness of the metal film is 0.5-3 nm.

[0017] Further, the fixed-point transfer technology includes the following steps:

[0018] (1) Use a transfer platform and a microscope to precisely locate the positions of GaTe and PdSe2;

[0019] (2) Stack GaTe and PdSe2 through micromechanical operation to form a twisted heterojunction.

[0020] Further, the preparation of the electrodes adopts photolithography and electron beam evaporation processes, and the specific steps include:

[0021] (1) Spin-coat photoresist on the surface of the heterojunction and form an electrode pattern through photolithography;

[0022] (2) Use electron beam evaporation to deposit metal electrode materials;

[0023] (3) Strip the excess photoresist to complete the preparation of the electrodes.

[0024] The present invention further provides an application of the above-mentioned polarization photodetector. The detector has a high polarization ratio (>10) and high optoelectronic response performance in the ultraviolet-visible-infrared band.

[0025] In summary, the present invention has the following beneficial effects:

[0026] 1. The present invention prepares high-quality and large-size anisotropic two-dimensional materials by combining the gold film-assisted mechanical exfoliation method with the fixed-point transfer technology, reducing defects and contamination.

[0027] 2. By precisely controlling the twist angle and stacking mode of the heterojunction, interface defects and contamination are reduced, and the carrier transport efficiency is improved.

[0028] 3. Utilize the lattice structure characteristics of anisotropic two-dimensional materials to enhance the absorption and response to polarized light and improve the polarization ratio (>10).

[0029] 4. Through the design of anisotropic two-dimensional heterojunctions, ultraviolet-visible-infrared full-band detection is realized.

[0030] 5. By optimizing the metal film-assisted mechanical exfoliation and fixed-point transfer processes, the preparation process is simplified, and the equipment cost and process complexity are reduced. Description of the Drawings

[0031] Figure 1 is a schematic flow chart of the preparation method of the photodetector of the present invention;

[0032] Figure 2 is a schematic structural diagram of the twisted heterojunction polarization photodetector prepared by the present invention;

[0033] Figure 3It is the optical microscope image of the heterojunction photodetector with different rotation angles of the present invention;

[0034] Figure 4 It is the optoelectronic performance test result of the detector prepared by the present invention in the ultraviolet-visible-infrared band. Specific embodiments

[0035] The following is a further detailed description of the present invention in conjunction with the attached Figures 1-3 Make a further detailed description of the present invention.

[0036] Example 1

[0037] Material preparation:

[0038] (1) Use tape to peel off single-layer or few-layer materials from bulk GaTe and PdSe2 crystals.

[0039] (2) Clean the silica substrate with acetone, ethanol and water respectively, then dry it with a nitrogen gun, and finally deposit a 1nm-thick gold film on its surface by electron beam evaporation.

[0040] (3) Transfer the single-layer or few-layer GaTe or PdSe2 peeled off by the above tape to the silica substrate coated with a gold film.

[0041] Heterojunction preparation:

[0042] (1) Use a two-dimensional material transfer platform and a microscope to accurately position GaTe and PdSe2.

[0043] (2) Stack GaTe and PdSe2 by micro-mechanical operation to form a heterojunction with a rotation angle of 0°.

[0044] Electrode preparation:

[0045] (1) Spin-coat photoresist on the surface of the heterojunction and form an electrode pattern by lithography.

[0046] (2) Deposit titanium (Ti) and gold (Au) electrodes by electron beam evaporation with thicknesses of 5nm and 50nm respectively.

[0047] (3) Peel off the excess photoresist to complete the electrode preparation.

[0048] Example 2

[0049] Material preparation:

[0050] (1) Use tape to peel off single-layer or few-layer materials from bulk GaTe and PdSe2 crystals.

[0051] (2) Clean the silicon wafer with acetone, ethanol and water respectively, then dry it with a nitrogen gun, and finally deposit a 1.5nm-thick gold film on its surface by electron beam evaporation.

[0052] (3) Transfer the single or few-layer GaTe or PdSe peeled from the above tape 2 onto a silicon wafer substrate coated with a gold film.

[0053] Heterojunction preparation:

[0054] (1) Use a two-dimensional material transfer platform and a microscope to precisely locate the positions of GaTe and PdSe2.

[0055] (2) Stack GaTe and PdSe2 by micro-mechanical operation to form a twist heterojunction with a twist angle of 30°.

[0056] Electrode preparation:

[0057] (1) Spin-coat photoresist on the surface of the heterojunction and form an electrode pattern through photolithography.

[0058] (2) Deposit titanium (Ti) and gold (Au) electrodes by electron beam evaporation with thicknesses of 5 nm and 50 nm respectively.

[0059] (3) Strip off the excess photoresist to complete the electrode preparation.

[0060] Example 3

[0061] Material preparation:

[0062] (1) Use tape to peel off single or few-layer materials from bulk GaTe and PdSe2 crystals.

[0063] (2) Clean the silica substrate with acetone, ethanol, and water respectively, then dry it with a nitrogen gun, and finally deposit a 2-nm-thick gold film on its surface by electron beam evaporation.

[0064] (3) Transfer the peeled single or few-layer GaTe or PdSe 2 onto the silica substrate.

[0065] Heterojunction preparation:

[0066] (1) Use a two-dimensional material transfer platform and a microscope to precisely locate the positions of GaTe and PdSe2.

[0067] (2) Stack GaTe and PdSe2 by micro-mechanical operation to form a twist heterojunction with a twist angle of 45°.

[0068] Electrode preparation:

[0069] (1) Spin-coat photoresist on the surface of the heterojunction and form an electrode pattern through photolithography.

[0070] (2) Deposit chromium (Cr) and gold (Au) electrodes by electron beam evaporation, with thicknesses of 5 nm and 50 nm respectively.

[0071] (3) Lift off the excess photoresist to complete the preparation of the electrodes.

[0072] This specific embodiment is only an explanation of the present invention and is not a limitation thereof. After reading this specification, those skilled in the art may make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A heterojunction polarization photodetector based on anisotropic two-dimensional materials, characterized by: It includes a substrate, anisotropic two-dimensional materials GaTe and PdSe2 prepared by a metal film-assisted mechanical exfoliation method, a corner heterojunction formed by stacking GaTe and PdSe2 by a fixed-point transfer technology, and a metal electrode for connecting the heterojunction and realizing photoelectric performance measurement.

2. The heterojunction polarization photodetector based on anisotropic two-dimensional materials according to claim 1, characterized in that: The substrate is a silicon wafer, a silicon dioxide substrate or a flexible substrate.

3. The heterojunction polarization photodetector based on anisotropic two-dimensional materials according to claim 1, characterized in that: The thickness of the anisotropic two-dimensional materials GaTe and PdSe2 is 1-10 layers.

4. The heterojunction polarization photodetector based on anisotropic two-dimensional materials according to claim 1, characterized in that: The rotation angle of the corner heterojunction ranges from 0° to 60°.

5. The heterojunction polarization photodetector based on anisotropic two-dimensional materials according to claim 1, characterized in that: The metal electrode material is gold (Au), chromium (Cr) or titanium (Ti), and the thickness is 10-100nm.

6. The method for preparing a polarization photodetector according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Preparation of anisotropic two-dimensional materials GaTe and PdSe2 by metal film-assisted mechanical exfoliation; S2. Stacking two-dimensional GaTe and PdSe2 to form a corner heterojunction through fixed-point transfer technology; S3. Photolithography electrodes on the heterojunction and complete device preparation and photoelectric testing.

7. The method for preparing a polarization photodetector according to claim 6, characterized in that: The metal film assisted mechanical stripping method comprises the following steps: (1) Use tape to peel off single or few layers of material from bulk GaTe and PdSe2 crystals; (2) The stripped material is transferred to a target substrate coated with a metal film, wherein the thickness of the metal film is 0.5-3 nm.

8. The method for preparing a polarization photodetector according to claim 1, characterized in that: The fixed-point transfer technology comprises the following steps: (1) Use a transfer platform and microscope to accurately locate the positions of GaTe and PdSe2; (2) GaTe and PdSe2 are stacked through micromechanical operation to form a corner heterojunction.

9. The method for preparing a polarization photodetector according to claim 1, characterized in that: The electrode is prepared by photolithography and electron beam evaporation process, and the specific steps include: (1) Spin-coating photoresist on the heterojunction surface and forming an electrode pattern by photolithography; (2) Deposition of metal electrode materials using electron beam evaporation; (3) Strip off excess photoresist to complete electrode preparation.

10. The use of the polarization photodetector according to any one of claims 1 to 5, characterized in that: The detector has a high polarization ratio (>10) and high photoelectric response performance in the ultraviolet-visible light-infrared band.

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