Near-infrared polarized photodetector and preparation method thereof

Abstract

The application discloses a near-infrared polarized photoelectric detector, which comprises a substrate, MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets, the MoTe2 nanosheets, the GeSe nanosheets and the MoS2 nanosheets are sequentially arranged above the substrate, and the MoTe2 nanosheets, the GeSe nanosheets and the MoS2 nanosheets are partially laminated to form a vertical heterojunction; a first electrode and a second electrode, the first electrode is arranged on the MoTe2 nanosheets which are not laminated, and the second electrode is arranged on the substrate and the MoS2 nanosheets which are not laminated. The application focuses on forming a MoS2 / GeSe / MoTe2 heterojunction, and the near-infrared polarized photoelectric detector takes the MoS2 nanosheets, the GeSe nanosheets and the MoTe2 nanosheets as the heterojunction. The energy band arrangement of the three MoS2, GeSe and MoTe2 two-dimensional materials in the heterojunction conforms to a type II energy band arrangement mode, and efficient charge transfer is realized. On the other hand, the GeSe two-dimensional material itself has anisotropic characteristics, and realizes the performance of polarized light detection as a sandwich in the formed heterojunction. The characteristics of wide-spectrum band response, rapid light detection, polarization sensitivity and stable performance are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric detectors, and particularly relates to a near-infrared polarized photoelectric detector and a preparation method. BACKGROUND

[0002] Photoelectric detection technology is the core of many technologies that affect modern human life, greatly enriching and facilitating people's daily life; in particular, polarized light detectors have a wide range of important applications in polarized imaging, image sensing, signal transmission and other fields due to their long action distance, strong penetration ability and good anti-interference performance. At present, most commercial photoelectric detectors are usually made of some traditional narrow-bandgap semiconductors such as indium gallium arsenide, mercury cadmium telluride, etc. However, the application of these photoelectric detectors is limited by their complex preparation process, high cost and low-temperature operating conditions. Therefore, there is an urgent need to develop new materials and new structures to meet the rapidly increasing demand for the development of polarized light detection technology.

[0003] In recent years, monatomic compounds of group IV-VI have become an important class of two-dimensional van der Waals materials due to their interesting physical properties such as high carrier mobility and optical anisotropy. Among them, GeSe crystal is a layered p-type semiconductor with high absorption coefficient (~10 5 cm -1 ) and high carrier mobility (~128 cm 2 V -1 s -1 ). The band gap of GeSe crystal is very narrow, which can be from 1.08 to 1.7 eV. Therefore, GeSe crystal has been applied to broadband light detection in a wide spectral range, especially in the near-infrared field, and there has been considerable development. The near-infrared polarized photoelectric detector based on GeSe crystal cannot simultaneously achieve high polarization ratio, high responsivity and fast response speed. Therefore, there is an urgent need to improve the performance of the near-infrared polarized photoelectric detector based on GeSe crystal. SUMMARY

[0004] The present application provides a near-infrared polarized photoelectric detector and a preparation method to solve the problems in the prior art.

[0005] To solve the above technical problems, the present application solves the problems by the following technical solutions:

[0006] A near-infrared polarized photoelectric detector, comprising:

[0007] a substrate;

[0008] MoTe2nanosheets, GeSe nanosheets and MoS2nanosheets are sequentially located above the substrate, and the MoTe2nanosheets, GeSe nanosheets and MoS2nanosheets are partially laminated to form a vertical heterojunction;

[0009] A first electrode and a second electrode, the first electrode is arranged on the substrate and the un-laminated MoTe2nanosheets, and the second electrode is arranged on the substrate and the un-laminated MoS2nanosheets.

[0010] As an implementable manner, the thickness of the MoTe2nanosheets is 10nm to 60nm.

[0011] As an implementable manner, the thickness of the GeSe nanosheets is 10nm to 60nm.

[0012] As an implementable manner, the thickness of the MoS2nanosheets is 10nm to 60nm.

[0013] As an implementable manner, the materials of the first electrode and the second electrode are metal Au respectively, and the thicknesses of the first electrode and the second electrode are 50nm respectively.

[0014] As an implementable manner, the substrate is a Si / SiO2substrate, and the thickness of the SiO2layer is 300nm.

[0015] A preparation method of a near-infrared polarized photodetector, comprising the following steps:

[0016] Providing a substrate;

[0017] Providing MoTe2nanosheets, GeSe nanosheets and MoS2nanosheets respectively, the MoTe2nanosheets, GeSe nanosheets and MoS2nanosheets are sequentially located above the substrate, and the MoTe2nanosheets, GeSe nanosheets and MoS2nanosheets are partially laminated to form a vertical heterojunction;

[0018] Forming a first electrode and a second electrode, the first electrode is arranged on the substrate and the un-laminated MoTe2nanosheets, and the second electrode is arranged on the substrate and the un-laminated MoS2nanosheets.

[0019] As an implementable manner, the MoTe2nanosheets, GeSe nanosheets and MoS2nanosheets are sequentially located above the substrate, and the MoTe2nanosheets, GeSe nanosheets and MoS2nanosheets are partially laminated to form a vertical heterojunction, comprising the following steps:

[0020] Obtaining MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets on the substrate based on the tape peeling method respectively and determining the appropriate thickness;

[0021] Taking an appropriate amount of polyvinyl alcohol liquid onto the PDMS and heating to form a polyvinyl alcohol carrier;

[0022] Covering the polyvinyl alcohol carrier to the GeSe nanosheets and the MoS2 nanosheets respectively, and heating to obtain a polyvinyl alcohol / GeSe nanosheet adhesive layer and a polyvinyl alcohol / MoS2 nanosheet adhesive layer;

[0023] Covering part of the polyvinyl alcohol / GeSe nanosheet adhesive layer on the MoTe2 nanosheets, and removing the polyvinyl alcohol to form a GeSe / MoTe2 heterojunction;

[0024] Covering part of the polyvinyl alcohol / MoS2 nanosheet adhesive layer on the GeSe / MoTe2 heterojunction, and removing the polyvinyl alcohol to form a vertical heterojunction, wherein the vertical heterojunction is a MoS2 nanosheet, a GeSe nanosheet and a MoTe2 nanosheet partially laminated.

[0025] As an implementable manner, the polyvinyl alcohol liquid is obtained by the following method:

[0026] The polyvinyl alcohol is taken out and stirred in deionized water, the stirring speed is 1000r, and the stirring time is 10 to 12 hours.

[0027] As an implementable manner, the following steps are further included:

[0028] Before obtaining the MoTe2 nanosheets, the GeSe nanosheets and the MoS2 nanosheets on the substrate based on the tape peeling method respectively, sequentially treating with acetone, isopropanol, ethanol and deionized water for 10 minutes each by ultrasonic, and then placing in plasma for 20 minutes.

[0029] As an implementable manner, the step of annealing under inert gas condition is further included, specifically:

[0030] The annealing temperature is 100℃ to 150℃, and the annealing time is 0.3h to 1h.

[0031] The present application has the following technical effects:

[0032] The structure of the application or the structure prepared based on the exemplary method focuses on forming a MoS2 / GeSe / MoTe2 heterojunction, and a near-infrared polarized photodetector with MoS2 nanosheets, GeSe nanosheets and MoTe2 nanosheets as a heterojunction. The heterojunction has a band arrangement of three layers of MoS2, GeSe and MoTe2 two-dimensional materials in a type II band arrangement mode, realizing efficient charge transfer. In addition, the similar band gap of the three also makes the heterojunction have good response in the near-infrared wave band (808, 1310 and 1550 nm). On the other hand, the GeSe two-dimensional material itself has anisotropic characteristics, and as a sandwich layer in the formed heterojunction, it realizes the performance of polarized light detection. In addition, the near-infrared polarized photodetector has excellent photovoltaic characteristics, realizing the characteristics of wide-spectrum band response (405-1550 nm), fast light detection (response time of 17 ms), polarization sensitivity (anisotropic photocurrent ratio of 15.23) and stable performance.

[0033] In addition, the preparation method of the application is mature in technology, low in cost and simple in preparation process. The prepared near-infrared polarized photodetector is stable and reliable in performance, suitable for large-scale production, and promotes the application of two-dimensional materials in photovoltaic devices and high-performance infrared photodetectors. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0035] Figure 1 is a schematic diagram of the overall structure of the near-infrared polarized photodetector of the application;

[0036] Figure 2 is an optical microscope image of the near-infrared polarized photodetector based on the MoS2 / GeSe / MoTe2 heterojunction.

[0037] Figure 3 is a current-time curve diagram of the near-infrared polarized photodetector based on the MoS2 / GeSe / MoTe2 heterojunction under different wavelengths.

[0038] Figure 4 is a self-driven response time curve diagram of the near-infrared polarized photodetector based on the MoS2 / GeSe / MoTe2 heterojunction under 635 nm laser.

[0039] Figure 5A three-dimensional structure diagram of a near-infrared polarized photodetector based on a MoS2 / GeSe / MoTe2 heterojunction under polarized light irradiation.

[0040] Figure 6 A light irradiation current-angle polar coordinate diagram of a near-infrared polarized photodetector based on a MoS2 / GeSe / MoTe2 heterojunction under 635 nm incident light. DETAILED DESCRIPTION

[0041] The application will be further described below in conjunction with examples, which are intended to explain the application but not limit the application to the examples.

[0042] Spatially relative terms such as "under", "below", "lower", "over", "upper", "on", and the like, are used to describe an element's position as related to the position of another element, as illustrated in the figures. These terms are intended to encompass different orientations of the device in addition to those depicted in the figures.

[0043] In addition, the use of terms such as "first", "second", etc., to describe various elements, layers, regions, sections, etc., is not intended to be limiting. The use of "have", "has", "have", "including", "including", etc., is an open term, indicating the presence of the stated element or feature, but not excluding additional elements or features. Unless the context clearly indicates otherwise.

[0044] Exemplary structure:

[0045] A near-infrared polarized photodetector, comprising: a substrate; MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets, the MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets being sequentially located above the substrate, and the MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets being partially laminated to form a vertical heterojunction; a first electrode and a second electrode, the first electrode being provided on the substrate and the un-laminated MoTe2 nanosheet, and the second electrode being provided on the substrate and the un-laminated MoS2 nanosheet.

[0046] Exemplary method:

[0047] A method for preparing a near-infrared polarized photodetector, comprising the following steps:

[0048] Providing a substrate;

[0049] Providing MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets, respectively, the MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets being sequentially located above the substrate, and the MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets being partially laminated to form a vertical heterojunction;

[0050] Forming the first electrode and the second electrode, the first electrode is arranged on the substrate and the un-laminated MoTe2 nanosheet, and the second electrode is arranged on the substrate and the un-laminated MoS2 nanosheet.

[0051] In more detail, the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are provided respectively, the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are sequentially located above the substrate, and the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are partially laminated to form a vertical heterojunction, comprising the following steps:

[0052] The MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are obtained on the substrate based on the tape peeling method respectively and the appropriate thickness is determined;

[0053] An appropriate amount of polyvinyl alcohol liquid is taken to the PDMS and heated to form a polyvinyl alcohol carrier;

[0054] The polyvinyl alcohol carrier is covered on the GeSe nanosheet and the MoS2 nanosheet respectively, and the polyvinyl alcohol / GeSe nanosheet adhesive layer and the polyvinyl alcohol / MoS2 nanosheet adhesive layer are obtained by heating;

[0055] Part of the polyvinyl alcohol / GeSe nanosheet adhesive layer is covered on the MoTe2 nanosheet, and the polyvinyl alcohol is removed to form a GeSe / MoTe2 heterojunction;

[0056] Part of the polyvinyl alcohol / MoS2 nanosheet adhesive layer is covered on the GeSe / MoTe2 heterojunction, and the polyvinyl alcohol is removed to form a vertical heterojunction, wherein the vertical heterojunction is a MoS2 nanosheet, a GeSe nanosheet and a MoTe2 nanosheet partially laminated.

[0057] The structure of the application or the structure prepared based on the exemplary method focuses on forming a MoS2 / GeSe / MoTe2 heterojunction, and the near-infrared polarized photodetector takes the MoS2 nanosheet, the GeSe nanosheet and the MoTe2 nanosheet as the heterojunction, the energy band arrangement of the three layers of MoS2, GeSe and MoTe2 two-dimensional materials in the heterojunction conforms to the type II energy band arrangement mode, and efficient charge transfer is realized; and the similar band gap of the three also makes the heterojunction show good response in the near-infrared wave band (808, 1310 and 1550 nm). On the other hand, the GeSe two-dimensional material itself has the anisotropic characteristic, and as a sandwich layer in the formed heterojunction, it realizes the performance of polarized light detection. In addition, the near-infrared polarized photodetector shows excellent photovoltaic characteristics, realizes the characteristics of wide spectrum band response (405-1550 nm), fast light detection (response time is 17 ms), polarization sensitivity (anisotropic photocurrent ratio is 15.23) and stable performance.

[0058] In addition, the preparation method of the present invention is technically mature, low in cost and simple in process. The near-infrared polarized photodetector prepared by the invention has stable and reliable performance and is suitable for large-scale production, which promotes the application of two-dimensional materials in the fields of photovoltaic devices and high-performance infrared photodetectors.

[0059] Example 1:

[0060] A near-infrared polarized photodetector, such as Figure 1 As shown, it includes:

[0061] Substrate 1;

[0062] MoTe2 nanosheet 2, GeSe nanosheet 3 and MoS2 nanosheet 4 are arranged sequentially on the substrate 1, and the MoTe2 nanosheet 2, GeSe nanosheet 3 and MoS2 nanosheet 4 are partially stacked to form a vertical heterojunction.

[0063] The first electrode 5 and the second electrode 6 are disposed on the substrate 1 and the unstacked MoTe2 nanosheet 2, respectively.

[0064] For the specific structure of vertical heterojunctions, please refer to the appendix. Figure 1 As shown, MoTe2 nanosheets 2, GeSe nanosheets 3, and MoS2 nanosheets 4 are sequentially positioned above substrate 1, and their stacking is partial (more vividly described as a staircase-like stacking), not completely overlapping. It is precisely this vertical heterojunction that enables the near-infrared polarization photodetector to achieve efficient charge transfer; furthermore, the similar bandgap widths of the three nanosheets allow the heterojunction to exhibit good response in the near-infrared band (808, 1310, and 1550 nm). On the other hand, the anisotropic nature of the GeSe two-dimensional material allows it to function as a sandwich layer in the formed heterojunction, enabling polarization detection. In addition, the near-infrared polarization photodetector exhibits excellent photovoltaic characteristics, achieving a broad-spectrum response (405–1550 nm), fast photodetection (response time of 20 ms), polarization sensitivity (anisotropic photocurrent ratio of 15.23), and stable performance.

[0065] In all embodiments, the thickness of MoTe2 nanosheet 2 is 10 nm to 60 nm. The thickness of GeSe nanosheet 3 is 10 nm to 60 nm. The thickness of MoS2 nanosheet 4 is 10 nm to 60 nm.

[0066] In addition, the materials of the first electrode 5 and the second electrode 6 are metal Au, and the thicknesses of the first electrode 5 and the second electrode 6 are 50 nm.

[0067] In the preparation process, the substrate 1 is preferably a Si / SiO2 substrate, the Si layer is below, the SiO2 layer 11 is above, and the thickness of the SiO2 layer 11 is 300 nm, and the thickness of the Si layer is not limited.

[0068] Figure 2 is an optical microscope image of the near-infrared polarized photodetector of the present application. Figure 2 Figure 3 is a current-time curve of the near-infrared polarized photodetector of the present application under different wavelengths.

[0069] Figure 4 is a current-time curve of the near-infrared polarized photodetector of the present application under different wavelengths. Figure 3 Figure 5 is a self-driven response time curve of the near-infrared polarized photodetector of the present application under 635nm laser. Figure 3 It can be seen that the on-state and off-state current of the near-infrared polarized photodetector based on the MoS2 / GeSe / MoTe2 vertical heterojunction changes stably and repeatedly under different incident wavelengths, and has excellent multi-wavelength response light switching characteristics.

[0070] Figure 6 is a normalized light current-angle polar coordinate graph of the near-infrared polarized photodetector of the present application under 635nm incident light. Figure 4 Figure 7 is a normalized light current-angle polar coordinate graph of the near-infrared polarized photodetector of the present application under 635nm incident light. Figure 4 It can be seen that the near-infrared polarized photodetector based on the MoS2 / GeSe / MoTe2 vertical heterojunction has a double-leaf polarized photocurrent behavior under 635nm illumination, the anisotropic photocurrent ratio is 15.23, and the angle of the maximum photocurrent 1.24nA is 80°.

[0071] Figure 6 Figure 6 is a normalized light current-angle polar coordinate graph of the near-infrared polarized photodetector of the present application under 635nm incident light. Figure 5 6 It can be seen that the near-infrared polarized photodetector based on the MoS2 / GeSe / MoTe2 vertical heterojunction has a double-leaf polarized photocurrent behavior under 635nm illumination, the anisotropic photocurrent ratio is 15.23, and the angle of the maximum photocurrent 1.24nA is 80°.

[0072] Example 2:

[0073] A preparation method of a near-infrared polarized photodetector, comprising the following steps:

[0074] providing a substrate;

[0075] ​The MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are provided respectively, and the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are sequentially located above the substrate, and the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are partially laminated to form a vertical heterojunction.

[0076] The first electrode and the second electrode are formed, the first electrode is arranged on the substrate and the un-laminated MoTe2 nanosheet, and the second electrode is arranged on the substrate and the un-laminated MoS2 nanosheet.

[0077] In one embodiment, the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are provided respectively, and the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are sequentially located above the substrate, and the MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are partially laminated to form a vertical heterojunction, comprising the following steps:

[0078] The MoTe2 nanosheet, the GeSe nanosheet and the MoS2 nanosheet are obtained on the substrate based on the tape peeling method and the appropriate thickness is determined;

[0079] An appropriate amount of polyvinyl alcohol liquid is taken to the PDMS and heated to form a polyvinyl alcohol carrier;

[0080] The polyvinyl alcohol carrier is covered on the GeSe nanosheet and the MoS2 nanosheet respectively, and heated to obtain a polyvinyl alcohol / GeSe nanosheet adhesive layer and a polyvinyl alcohol / MoS2 nanosheet adhesive layer;

[0081] Part of the polyvinyl alcohol / GeSe nanosheet adhesive layer is covered on the MoTe2 nanosheet, and the polyvinyl alcohol is removed to form a GeSe / MoTe2 heterojunction;

[0082] Part of the polyvinyl alcohol / MoS2 nanosheet adhesive layer is covered on the GeSe / MoTe2 heterojunction, and the polyvinyl alcohol is removed to form a vertical heterojunction, wherein the vertical heterojunction is a MoS2 nanosheet, a GeSe nanosheet and a MoTe2 nanosheet partially laminated.

[0083] The following detailed preparation method can be referred to:

[0084] The Si / SiO2 substrate is ultrasonically cleaned with acetone, isopropyl alcohol, ethanol and deionized water for 10 minutes, and dried with a nitrogen gun;

[0085] The substrate is placed in ozone ultraviolet or oxygen plasma for cleaning for 20 minutes, wherein the oxygen flow is 50 sccm and the plasma power is 100 W.

[0086] MoS2nanosheets, GeSe nanosheets and MoTe2nanosheets are obtained on the cleaned Si / SiO2substrate by micromechanical exfoliation, and the thickness of the SiO2layer in the Si / SiO2substrate is 300 nm.

[0087] The dry adhesive polyvinyl alcohol (PVA) is prepared: the ratio of PVA to deionized water is 4:21 (g / ml), and other ratios can be used in other embodiments, which are not limited herein. In this embodiment, 4 g of PVA particles (MW = 27000) are weighed and placed in a beaker containing 21 ml of deionized water, and then placed on a magnetic stirrer, stirred at a speed of 1000 r at room temperature for 10-12 hours, and finally a transparent viscous liquid is obtained.

[0088] A 0.5 cm x 0.3 cm PDMS is placed on a transparent glass slide, and then an appropriate amount of viscous liquid PVA is dropped on the PDMS through a rubber head dropper and flattened, and finally placed on a heating table at 50°C for 10 min to form a PVA transfer carrier.

[0089] The above PVA transfer carrier is respectively covered on the GeSe nanosheets and the MoS2nanosheets. The PVA transfer carrier is first covered on the GeSe nanosheets by the three-dimensional micro-area transfer platform, and the substrate is heated at 90°C for 4 min to make the PVA adhere tightly to the GeSe crystals, and then the PVA film with GeSe crystals is lifted and covered on the MoTe2nanosheets to form a GeSe / MoTe2heterojunction, and then heated in a 50°C water bath for 10-20 min in deionized water to remove the PVA; the above operation is repeated, the PVA transfer carrier is covered on the MoS2nanosheets, and the substrate is heated at 90°C for 4 min to make the PVA adhere tightly to the MoS2crystals, and then the PVA film with MoS2crystals is lifted and covered on the overlapping part of the GeSe / MoTe2to construct a MoS2 / GeSe / MoTe2three-layer vertical heterojunction, and then heated in a 50°C water bath for 10-20 min in deionized water to remove the PVA, and finally dried with nitrogen to obtain a clean heterojunction.

[0090] The first electrode and the second electrode are prepared on the MoS2nanosheets and the MoTe2nanosheets. The prepared heterojunction is exposed to light and then developed to complete the patterning of the electrodes. Then 50 nm of the first electrode and the second electrode are deposited on the MoS2nanosheets and the MoTe2nanosheets by thermal evaporation, and the vacuum degree during thermal evaporation is 6 x 10 -4 pa, and the evaporation rate is balanced at 0.5 / s.

[0091] Finally, the device after evaporation is placed in acetone for ten minutes to remove the photoresist, and a needle tube is used to flush water, and as the photoresist is dissolved by acetone, the excess Au film is also removed by flushing operation, and then the device is placed in deionized water, and the water on the surface of the silicon wafer is blown clean by a nitrogen gun, and then annealing is carried out in an inert gas, the inert gas is selected from nitrogen and argon, the annealing temperature is 100-150 DEG C, the annealing time is 30-60 minutes, so as to improve the contact quality between the electrode and the MoS2 / GeSe / MoTe2 van der Waals heterojunction and reduce the contact potential barrier, and after cooling, a near-infrared detector with uniform surface and stable performance is obtained.

[0092] attached Figure 2 Figure is an optical microscope image of the near-infrared polarized photodetector of the present application. MoS2 nanosheets, GeSe nanosheets and MoTe2 nanosheets are overlapped to form MoS2 / GeSe / MoTe2 vertical heterojunction, and the first electrode and the second electrode are respectively located on the non-overlapping MoS2 nanosheet and MoTe2 nanosheet.

[0093] attached Figure 3 Figure is a current-time curve of the near-infrared polarized photodetector of the present application under different wavelengths, and Figure 3 It can be seen that the on-state and off-state current of the near-infrared polarized photodetector based on MoS2 / GeSe / MoTe2 vertical heterojunction under different incident wavelengths is stable and repeatable, and has excellent multi-wavelength response light switching characteristics.

[0094] attached Figure 4 Figure is a self-driven response time curve of the near-infrared polarized photodetector of the present application under 635nm laser, and Figure 4 It can be seen that the response time of the MoS2 / GeSe / MoTe2 heterojunction photodetector under 635nm incident wavelength is 17ms, which shows that under the action of type II band arrangement and built-in electric field, photo-generated carriers can be quickly separated.

[0095] attached Figure 6 Figure is a normalized light current-angle polar coordinate graph of the near-infrared polarized photodetector of the present application under 635nm incident light. By Figure 5 and 6 It can be seen that the near-infrared polarized photodetector based on MoS2 / GeSe / MoTe2 vertical heterojunction has a double-leaf polarized photocurrent behavior under 635nm illumination, the anisotropic photocurrent ratio is 15.23, and the angle of the maximum photocurrent 1.24nA is 80 DEG.

[0096] Moreover, it should be noted that the specific embodiments described in the specification, the shape of the parts, the names taken, etc. can be different. Any equivalent or simple change made in accordance with the structure, features and principles described in the patent concept of the present application is included in the protection scope of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace, as long as they do not deviate from the structure of the present application or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A near-infrared polarized photodetector, characterized in that, include: Substrate; MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets are arranged sequentially on the substrate, and the MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets are partially stacked to form a vertical heterojunction. The first electrode and the second electrode are disposed on the substrate and the unstacked MoTe2 nanosheets.

2. The near-infrared polarization photodetector according to claim 1, characterized in that, The thickness of the MoTe2 nanosheets ranges from 10 nm to 60 nm.

3. The near-infrared polarization photodetector according to claim 1, characterized in that, The thickness of the GeSe nanosheets is 10 nm to 60 nm.

4. The near-infrared polarization photodetector according to claim 1, characterized in that, The thickness of the MoS2 nanosheets ranges from 10 nm to 60 nm.

5. The near-infrared polarization photodetector according to claim 1, characterized in that, The first electrode and the second electrode are both made of metallic Au, and their thicknesses are both 50 nm.

6. The near-infrared polarization photodetector according to claim 1 or 2, characterized in that, The substrate is a Si / SiO2 substrate, and the thickness of the SiO2 layer is 300 nm.

7. A method for fabricating a near-infrared polarized photodetector, characterized in that, Includes the following steps: Provide substrate; MoTe2 nanosheets, GeSe nanosheets, and MoS2 nanosheets are provided respectively, and the MoTe2 nanosheets, GeSe nanosheets, and MoS2 nanosheets are sequentially located above the substrate, and the MoTe2 nanosheets, GeSe nanosheets, and MoS2 nanosheets are partially stacked to form a vertical heterojunction; A first electrode and a second electrode are formed, wherein the first electrode is disposed on the substrate and the unstacked MoTe2 nanosheets, and the second electrode is disposed on the substrate and the unstacked MoS2 nanosheets.

8. The method for fabricating a near-infrared polarized photodetector according to claim 7, characterized in that, The method involves providing MoTe2 nanosheets, GeSe nanosheets, and MoS2 nanosheets, which are sequentially positioned above the substrate. The MoTe2, GeSe, and MoS2 nanosheets are partially stacked to form a vertical heterojunction. The method includes the following steps: MoTe2 nanosheets, GeSe nanosheets, and MoS2 nanosheets were obtained on the substrate using a tape peeling method, and appropriate thicknesses were determined. Take an appropriate amount of polyvinyl alcohol liquid onto PDMS and heat it to form a polyvinyl alcohol carrier; The polyvinyl alcohol carrier was coated onto the GeSe nanosheets and the MoS2 nanosheets respectively, and heated to obtain a polyvinyl alcohol / GeSe nanosheet adhesive layer and a polyvinyl alcohol / MoS2 nanosheet adhesive layer; The polyvinyl alcohol / GeSe nanosheet adhesive layer is partially covered on the MoTe2 nanosheet, and the polyvinyl alcohol is removed to form a GeSe / MoTe2 heterojunction; The polyvinyl alcohol / MoS2 nanosheet adhesive layer is partially covered onto the GeSe / MoTe2 heterojunction, and the polyvinyl alcohol is removed to form a vertical heterojunction, wherein the vertical heterojunction is a partial stacking of MoS2 nanosheets, GeSe nanosheets and MoTe2 nanosheets.

9. The method for fabricating a near-infrared polarized photodetector according to claim 8, characterized in that, The polyvinyl alcohol liquid is obtained by the following method: Polyvinyl alcohol is placed in deionized water and stirred at a speed of 1000 rpm for 10 to 12 hours.

10. The method for fabricating a near-infrared polarized photodetector according to claim 8, characterized in that, It also includes the following steps: Before obtaining MoTe2 nanosheets, GeSe nanosheets and MoS2 nanosheets on the substrate by tape peeling method, the substrate was subjected to ultrasonic treatment for 10 min each with acetone, isopropanol, ethanol and deionized water, and then cleaned in plasma for 20 min.

11. The method for fabricating a near-infrared polarized photodetector according to claim 7 or 8, characterized in that, It also includes the step of annealing under inert gas conditions, specifically: The annealing temperature is 100℃ to 150℃; the annealing time is 0.3h to 1h.

Images