MoS2 / MLG / MoTe2 heterojunction photoelectric detector with controllable polarity photoresponse and preparation method of MoS2 / MLG / MoTe2 heterojunction photoelectric detector

Abstract

The invention discloses a preparation method of a controllable polarity photoresponse MoS2 / MLG / MoTe2 heterojunction photoelectric detector. The preparation method comprises the following steps: forming a source metal electrode and a drain metal electrode on a Si / SiO2 substrate; a MoS2 nanosheet, a multi-layer graphene nanosheet and a MoTe2 nanosheet are sequentially transferred and stacked on a Si / SiO2 substrate and between a source metal electrode and a drain metal electrode, then the MoS2 / MLG / MoTe2 heterojunction photoelectric detector is obtained through cleaning and blow-drying, the MoS2 nanosheet and the MoTe2 nanosheet are connected with the source metal electrode and the drain metal electrode respectively, and the MoS2 nanosheet and the MoTe2 nanosheet are not in contact. The photoelectric detector prepared by the preparation method can realize large-area controllable polarity light response and relatively high photoelectric response sensitivity.

Description

Technical Field

[0001] The present invention belongs to the field of information technology, and particularly relates to a MoS 2 / MLG / MoTe 2 heterojunction photodetector with controllable polarization light response and a preparation method thereof. Background Art

[0002] Polarization light response provides greater flexibility in environmental adaptability, signal modulation, and dynamic recognition due to its unique advantages, showing great application potential in the fields of multi-dimensional detection and high-resolution imaging. Currently, polarization light detectors based on this technology have demonstrated important application values in multiple fields such as autonomous sensing systems, high-precision target recognition, biological vision bionics, environmental monitoring, and intelligent optoelectronic sensing. For example, in artificial vision systems, polarization light response can simulate the adaptation mechanism of the human eye to different lighting environments, thereby enhancing the visual perception ability of imaging devices in dynamic light fields. In addition, in the aspect of target recognition under low visibility conditions, this technology has been applied to night vision monitoring, remote sensing detection, and security protection systems, greatly improving the accuracy and stability of target detection. Given these outstanding performances, polarization light detectors are expected to drive the breakthrough of a new generation of intelligent sensing technologies and play a crucial role in the development of future high-performance optoelectronic devices.

[0003] However, with the continuous expansion of application scenarios, the polarization light response technology also faces more stringent performance requirements, including higher photoelectric conversion efficiency, more excellent detection performance, faster response speed, and more precise control of polarization.

[0004] Nowadays, researchers are committed to developing controllable polarization light response through strategic performance band alignment engineering and innovative device architectures, and significant progress has been made in various material systems (such as WSe2, MoTe2, and BP).

[0005] The literature "Polarization-and Gate-Tunable Optoelectronic Reverse in 2D Semimetal / Semiconductor Photovoltaic Heterostructure, 2024, 36, 2309371." discloses a polarization photodetector based on the semimetal 1T′-MoTe 2 and bipolar WSe 2 realized the optoelectronic inversion phenomenon through gate voltage regulation and polarization detection technology, and has a current rectification ratio of 10 -2 to 10 3

[0006] ​The literature "Graphene / Organic Semiconductor Heterojunction Phototransistors with Broadband and Bi-Directional Photoresponse, 2018, 30, 1804020." discloses a polar phototransistor based on a graphene-organic semiconductor heterojunction. At different wavelengths, due to the unique band alignment between graphene and the organic semiconductor layer, the charge transfer direction of photoexcited carriers is opposite, resulting in a bi-directional (positive and negative) photoresponse.

[0007] The polar photodetector disclosed in the above literature has made progress in the realization and manipulation of polar photoresponse, but the limitation of the polar response region still restricts its practical implementation in large-scale applications. Therefore, achieving a large-area controllable polar photoresponse remains a major challenge to be solved. Summary of the Invention

[0008] The present invention provides a method for preparing a MoS 2 / MLG / MoTe 2 heterojunction photodetector, and the photodetector prepared by this preparation method can achieve a large-area controllable polar photoresponse.

[0009] The present invention provides a method for preparing a MoS 2 / MLG / MoTe 2 heterojunction photodetector, comprising:

[0010] (1) Forming source and drain metal electrodes on a Si / SiO 2 substrate;

[0011] (2) Transferring and stacking MoS 2 nanosheets, multi-layer graphene nanosheets, and MoTe 2 nanosheets in sequence between the source and drain metal electrodes on the Si / SiO 2 substrate, and then cleaning and drying to obtain a MoS 2 / MLG / MoTe 2 heterojunction photodetector, wherein the MoS 2 nanosheets and MoTe 2 nanosheets are respectively connected to the source and drain metal electrodes, and the MoS 2 nanosheets and MoTe 2 nanosheets do not contact.

[0012] In the present invention, the equivalent electric field formed by the three material regions is related to MoTe 2Under the combined action of the Schottky junction with the metal electrode, two reverse-polarity current regions are formed. At the same time, the introduction of intercalated graphene brings many significant advantages to the heterojunction structure: its high carrier mobility and excellent conductivity provide an efficient transmission channel for the device; the two built-in electric fields in the same direction optimize the carrier transport process. In addition, the improvement of the interface quality effectively reduces the recombination loss and improves the overall performance of the device. Under the synergistic effect of the above three aspects, a large-area uniform negative photoresponse region can be formed. More importantly, this polarity response can be precisely regulated by the bias voltage, enabling the device to selectively enhance or suppress the broadband light response according to different needs, thereby endowing it with more extensive application potential.

[0013] Preferably, the MoS 2 nanosheets, graphene nanosheets, and MoTe 2 nanosheets are all layered materials. The number of layers of the MoS 2 nanosheets is 8 - 25 layers, the number of layers of the graphene nanosheets is 5 - 10 layers, and the number of layers of the MoTe 2 nanosheets is 30 - 50 layers.

[0014] By precisely controlling the number of layers of the three nanosheets in the present invention, not only can it absorb a large number of photons, but also the anti-deformation and anti-twisting abilities of the material are enhanced, thereby improving the stability of the overall structure. At the same time, this optimized design effectively avoids problems such as the extension of the carrier transport path and material waste caused by the excessive thickness of the material, and while improving the photoelectric conversion efficiency, better device performance and material utilization rate are achieved.

[0015] Preferably, the MoS 2 nanosheets are in the 2H configuration, and the MoTe 2 nanosheets are in the 2H configuration.

[0016] Preferably, after transferring the MoS 2 , MLG, and MoTe 2 nanosheets respectively, they are all soaked in hot acetone for 30 - 60 min, and then soaked in cold acetone for 1 - 2 h to remove the transfer residual glue.

[0017] Preferably, the Si / SiO 2 substrate is a hydrophobic substrate.

[0018] Preferably, the source and drain metal electrodes are both Ti / Au metal electrodes. Among them, the thickness of the Ti metal electrode is 5 - 15 nm, and the thickness of the Au metal electrode is 50 - 70 nm.

[0019] Preferably, the channel width between the source and drain metal electrodes is 30 - 60 μm.

[0020] On the other hand, the present invention also provides a MoS with controllable polar light response 2 / MLG / MoTe 2 heterojunction photodetector, which is prepared by the preparation method of the MoS 2 / MLG / MoTe 2 heterojunction photodetector with controllable polar light response.

[0021] Preferably, under no external bias voltage, the area ratio of the positive and negative currents of the MoS 2 / MLG / MoTe 2 heterojunction photodetector is 1:4 - 6.

[0022] The present invention innovatively proposes a polar light response regulation scheme based on graphene intercalation technology, and successfully prepares a MoS with large-area uniform and controllable polar light response by using this condition 2 / MLG / MoTe 2 heterojunction photodetector. The present invention selects commercial hydrophobic Si / SiO 2 as the substrate material, and uses a high-vacuum evaporation device to prepare metal electrodes. Subsequently, MoS 2 , graphene and MoTe 2 nanosheets are transferred in sequence to construct a MoS 2 / MLG / MoTe 2 vertical stacking structure. After organic cleaning treatment, a MoS with large-area uniform and controllable polar light response can be obtained 2 / MLG / MoTe 2 heterojunction photodetector. The present invention has significant process advantages: the operation process is simple, the reproducibility is good, and the requirements for the experimental environment and equipment are low, greatly reducing the preparation cost. This innovative scheme not only provides a reliable technical path for the development of large-area adjustable polar light response devices, but also provides an important reference for the design and manufacture of high-performance wide-spectrum optoelectronic devices.

[0023] Secondly, based on the optoelectronic detection device realized by the preparation method of the MoS 2 / MLG / MoTe 2 heterojunction photodetector with large-area uniform and controllable polar light response disclosed in the present invention, it has excellent optoelectronic imaging ability and can realize high-precision imaging of complex objects.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The present invention passes through in MoS 2 / MoTe 2Intercalation of multi-layer graphene is carried out in the heterojunction, achieving large-area uniform polar response in both visible light and infrared waves. Without an external bias voltage, a large-area negative photoconductivity (NPC) region and a small-area positive photoconductivity (PPC) region are formed. After adding a bias voltage for regulation, the device achieves large-area uniform single polarity. This work emphasizes the key role of manipulating polar light response in achieving high sensitivity and broadband detection, opening up a new approach for optimizing next-generation intelligent sensing chips through low-dimensional material insertion configurations. Description of the Drawings

[0026] Figure 1 MoS prepared for Example 1 2 / MLG / MoTe 2 Schematic diagram and optical microscope image of the heterojunction photodetector.

[0027] Figure 2 MoS prepared for Example 1 2 / MLG / MoTe 2 Material thickness characterization diagram of the heterojunction photodetector.

[0028] Figure 3 MoS prepared for Example 1 2 / MLG / MoTe 2 Raman spectrum diagram of the heterojunction photodetector.

[0029] Figure 4 MoS prepared for Example 1 2 / MLG / MoTe 2 Output curve of the heterojunction photodetector in the 638nm - 1550nm band;

[0030] Figure 5 MoS prepared for Example 1 2 / MLG / MoTe 2 Optical current mapping of the heterojunction photodetector at 940nm;

[0031] Figure 6 MoS prepared for Example 1 2 / MLG / MoTe 2 Optical current mapping of the heterojunction photodetector at 638nm;

[0032] Figure 7 MoS prepared for Example 1 2 / MLG / MoTe 2Photocurrent mapping of the heterojunction photodetector at 1550 nm wavelength;

[0033] Figure 8 For the MoS prepared in Example 1 2 / MLG / MoTe 2 Photovoltaic imaging diagram of the heterojunction photodetector. Detailed implementation manners

[0034] The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0035] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0036] Example 1

[0037] 1) The hydrophobic Si / SiO 2 substrate was ultrasonically cleaned in acetone, ethanol and deionized water for 20 minutes respectively, and the surface of the substrate was dried with high-purity nitrogen to obtain a substrate with high cleanliness. And a Ti / Au metal electrode with a thickness of 5 / 55 nm was prepared by using a high-vacuum evaporation device. The electrode channel widths were 30 (between horizontal electrodes) and 50 (between vertical electrodes).

[0038] 2) 16 layers of 2H-MoS 2 material was transferred to one end of the electrode by a fixed-point transfer technique. It was soaked in hot acetone for 30 minutes and then soaked in cold acetone for 2 h to remove the residual glue from the transfer.

[0039] 3) 7 layers of graphene were transferred to the surface of the 2H-MoS 2 material, and it was also soaked in hot acetone for 30 minutes and then soaked in cold acetone for 2 h to remove the residual glue from the transfer.

[0040] 4) 39 layers of 2H-MoTe 2 material was transferred above the multi-layer graphene by a fixed-point transfer technique without contacting the 2H-MoS 2 material. It was also soaked in hot acetone for 30 minutes and then soaked in cold acetone for 2 h to remove the residual glue from the transfer, and a MoS 2 / MLG / MoTe 2 heterojunction photodetector with a large-area uniform and controllable polarity light response was prepared.

[0041] As Figure 1As shown in (a) of, MoS 2 / MLG / MoTe 2 The heterojunction photodetector consists of molybdenum disulfide (MoS 2 ) nanosheets as the bottom layer, multilayer graphene (MLG) as the middle layer, and molybdenum telluride (MoTe 2 ) nanosheets as the top layer. During the experiment, MoS 2 is connected to the source electrode (S), and MoTe 2 is connected to the drain electrode (D). Figure 1 Figure (b) is the corresponding optical microscope image.

[0042] As Figure 2 shown, it can be seen that the thicknesses of the MoS 2 , MLG, and MoTe 2 nanosheets used in this embodiment are 11.1 nm (about 16 layers), 3.1 nm (about 7 layers), and 31.2 nm (about 39 layers) in sequence.

[0043] As Figure 3 shown, for the Raman spectrum of the MoS 2 / MLG / MoTe 2 heterojunction, there is no obvious peak shift compared with single materials, indicating good structural integrity and interface quality.

[0044] As Figure 4 shown in (a) at 638 nm, Figure 4 shown in (b) at 940 nm, and Figure 4 shown in (c) at 1550 nm of the output curves, the device has excellent optoelectronic response capabilities from visible light to infrared. Especially under weak light illumination conditions, the device can still generate an obviously distinguishable photocurrent, indicating its high sensitivity and wide spectral adaptability, and can achieve stable optoelectronic detection in a low light intensity environment.

[0045] As Figure 5 shown in (a), the device has two reverse current regions at the 940 nm wavelength band: the area ratio of PPC to NPC is 1:6. Under the negative bias as shown in Figure 5 Figure (b), the area of the NPC region further expands, and the PPC area region disappears. Under the positive bias as shown in Figure 5 Figure (c), the NPC region disappears, and the PPC region appears, indicating the polarity controllability of the device.

[0046] Figure 6 shows the photocurrent mapping at 638 nm. Similar to Figure 5 , under the condition of no applied bias as shown in Figure 6 Figure (a), the area ratio of PPC to NPC is 1:4. Under the condition as shown in Figure 6Under the negative bias shown in (b), the area of the negative current region also further expands, and the positive current area region disappears.

[0047] Figure 7 Figure 5 shows the photocurrent mapping of the device under negative bias at 1550 nm. The area of the negative current region also further expands, and the positive current area region disappears.

[0048] As Figure 8 shown in (a) and Figure 8 shown in (b), it can be seen that the device has the high-precision imaging ability for complex images.

[0049] Example 2

[0050] 1) The hydrophobic Si / SiO 2 substrate was ultrasonically cleaned in acetone, ethanol, and deionized water for 20 minutes respectively, and the surface of the substrate was dried with high-purity nitrogen to obtain a substrate with high cleanliness. And a Ti / Au metal electrode with a thickness of 10 / 60 nm was prepared by using a high-vacuum evaporation equipment. The electrode channel widths were 40 (between horizontal electrodes) and 60 (between vertical electrodes).

[0051] 2) Twenty layers of 2H-MoS 2 material was transferred to one end of the electrode by the fixed-point transfer technique. It was soaked in hot acetone for 30 minutes and then soaked in cold acetone for 2 h to remove the transfer residual glue.

[0052] 3) Ten layers of graphene were transferred to the surface of the 2H-MoS 2 material, and it was also soaked in hot acetone for 30 minutes and then soaked in cold acetone for 2 h to remove the transfer residual glue.

[0053] 4) Thirty-five layers of 2H-MoTe 2 material was transferred to the upper part of the multi-layer graphene by the fixed-point transfer technique without contacting the 2H-MoS 2 material. It was also soaked in hot acetone for 30 minutes and then soaked in cold acetone for 2 h to remove the transfer residual glue, and a MoS 2 / MLG / MoTe 2 heterojunction photodetector with large-area uniform and controllable polarity light response was prepared.

[0054] Example 3

[0055] 1) The hydrophobic Si / SiO 2 substrate was ultrasonically cleaned in acetone, ethanol, and deionized water for 20 minutes respectively, and the surface of the substrate was dried with high-purity nitrogen to obtain a substrate with high cleanliness. And a Ti / Au metal electrode with a thickness of 15 / 55 nm was prepared by using a high-vacuum evaporation equipment. The electrode channel widths were 30 (between horizontal electrodes) and 60 (between vertical electrodes).

[0056] 2) Transfer the 25-layer 2H-MoS 2 material to one end of the electrode by the fixed-point transfer technique. Immerse it in hot acetone for 30 minutes and then in cold acetone for 2 h to remove the residual glue from the transfer.

[0057] 3) Transfer 5-layer graphene to the surface of the 2H-MoS 2 material, and also immerse it in hot acetone for 30 minutes and in cold acetone for 2 h to remove the residual glue from the transfer.

[0058] 4) Transfer the 50-layer 2H-MoTe 2 material to above the multi-layer graphene by the fixed-point transfer technique without contacting the 2H-MoS 2 material. Also immerse it in hot acetone for 30 minutes and in cold acetone for 2 h to remove the residual glue from the transfer, and fabricate a MoS 2 / MLG / MoTe 2 heterojunction photodetector with large-area uniform and controllable polar light response.

[0059] Example 4

[0060] 1) Ultrasonically clean the hydrophobic Si / SiO 2 substrate in acetone, ethanol, and deionized water for 20 minutes respectively, and dry the substrate surface with high-purity nitrogen gas to obtain a substrate with high cleanliness. Use a high-vacuum evaporation equipment to fabricate a Ti / Au metal electrode with a thickness of 10 / 55 nm. The electrode channel widths are 30 (between horizontal electrodes) and 60 (between vertical electrodes).

[0061] 2) Transfer the 18-layer 2H-MoS 2 material to one end of the electrode by the fixed-point transfer technique. Immerse it in hot acetone for 30 minutes and then in cold acetone for 2 h to remove the residual glue from the transfer.

[0062] 3) Transfer 6-layer graphene to the surface of the 2H-MoS 2 material, and also immerse it in hot acetone for 30 minutes and in cold acetone for 2 h to remove the residual glue from the transfer.

[0063] 4) Transfer the 43-layer 2H-MoTe 2 material to above the multi-layer graphene by the fixed-point transfer technique without contacting the 2H-MoS 2 material. Also immerse it in hot acetone for 30 minutes and in cold acetone for 2 h to remove the residual glue from the transfer, and fabricate a MoS 2 / MLG / MoTe 2 heterojunction photodetector.

[0064] Example 5

[0065] 1) The hydrophobic Si / SiO 2 substrate was ultrasonically cleaned in acetone, ethanol, and deionized water for 20 minutes each, and the surface of the substrate was dried with high-purity nitrogen gas to obtain a substrate with high cleanliness. A Ti / Au metal electrode with a thickness of 15 / 60 nm was prepared using a high-vacuum evaporation device. The electrode channel widths were 40 (between horizontal electrodes) and 50 (between vertical electrodes).

[0066] 2) Twenty-one layers of 2H-MoS 2 material was transferred to one end of the electrode by a fixed-point transfer technique. It was soaked in hot acetone for 30 minutes and then in cold acetone for 2 h to remove the residual glue from the transfer.

[0067] 3) Nine layers of graphene were transferred onto the surface of the 2H-MoS 2 material, and it was also soaked in hot acetone for 30 minutes and then in cold acetone for 2 h to remove the residual glue from the transfer.

[0068] 4) Forty-six layers of 2H-MoTe 2 material was transferred onto the multi-layer graphene by a fixed-point transfer technique without contacting the 2H-MoS 2 material. It was also soaked in hot acetone for 30 minutes and then in cold acetone for 2 h to remove the residual glue from the transfer, and a MoS 2 / MLG / MoTe 2 heterojunction photodetector with large-area uniform and controllable polar light response was fabricated.

Claims

1. A method for preparing a MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response, characterized in that: include: (1) Forming source and drain metal electrodes on a Si / SiO2 substrate; (2) On a Si / SiO2 substrate, a MoS2 nanosheet, a multilayer graphene nanosheet and a MoTe2 nanosheet are sequentially transferred and stacked between a source and a drain metal electrode, and then cleaned and dried to obtain a MoS2 / MLG / MoTe2 heterojunction photodetector, wherein the MoS2 nanosheet and the MoTe2 nanosheet are connected to the source and the drain metal electrodes, respectively, and the MoS2 nanosheet and the MoTe2 nanosheet are not in contact.

2. The method for preparing the MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to claim 1, characterized in that: The MoS2 nanosheets, graphene nanosheets and MoTe2 nanosheets are all layered materials, and the number of layers is 8-25 layers, 5-10 layers and 30-50 layers respectively.

3. The method for preparing the MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to claim 1, characterized in that: The MoS2 nanosheets are of 2H configuration, and the MoTe2 nanosheets are of 2H configuration.

4. The method for preparing the MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to claim 1, characterized in that: After transferring MoS2, MLG, and MoTe2 nanosheets, respectively, they were all soaked in hot acetone for 30-60 min and then soaked in cold acetone for 1-2 h to remove the transfer residual glue.

5. The method for preparing the MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to claim 1, characterized in that: The Si / SiO2 substrate is a hydrophobic substrate.

6. The method for preparing the MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to claim 1, characterized in that: The source and drain metal electrodes are both Ti / Au metal electrodes, wherein the thickness of the Ti metal electrode is 5-15 nm, and the thickness of the Au metal electrode is 50-70 nm.

7. The method for preparing the MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to claim 1, characterized in that: The channel width between the source and drain metal electrodes is 30-60 μm.

8. A MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response, characterized in that: The device is prepared by the method for preparing a MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to any one of claims 1 to 7.

9. The MoS2 / MLG / MoTe2 heterojunction photodetector with controllable polarity light response according to claim 8, characterized in that: In the absence of an external bias, the area ratio of the positive and negative currents of the MoS2 / MLG / MoTe2 heterojunction photodetector is 1:4-6.

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