Infrared bipolar linearly polarized photoelectric detector and preparation method thereof
By utilizing van der Waals heterostructures of graphene, black phosphorus, and molybdenum disulfide, infrared bipolar linear polarization detection with reversible flipping of photocurrent sign along polarization direction was achieved. This solves the problems of accuracy and process complexity of traditional polarization photodetectors, improves polarization recognition accuracy and signal-to-noise ratio, and is suitable for high-performance artificial vision systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-04-07
AI Technical Summary
The polarization sensitivity and recognition accuracy of traditional polarization photodetectors are limited by material properties and noise levels, making it difficult to meet the requirements of high-resolution polarization imaging. Furthermore, existing technologies suffer from bottlenecks such as stringent antenna orientation design and complex fabrication processes.
By employing a van der Waals heterostructure based on black phosphorus (BP), molybdenum disulfide (MoS2), and graphene, and by controlling the polarity of the graphene channel through the bottom grating, a bipolar linear polarization detection effect with reversible flipping of the photocurrent sign with the polarization direction is achieved. The fabrication process is simplified and the polarization recognition accuracy is improved by utilizing the stacked structure of graphene multilayer channels with two-dimensional molybdenum disulfide and two-dimensional black phosphorus.
It realizes bipolar linear polarization detection with reversible flipping of photocurrent sign with polarization direction in the infrared band, significantly improving polarization recognition accuracy and signal-to-noise ratio. It has programmability and multi-functional integration potential, and is suitable for high-performance artificial neural network vision chips and intelligent sensing systems.
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Figure CN121815774A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor optoelectronic device technology, and in particular to an infrared bipolar linearly polarized photodetector and its fabrication method. Background Technology
[0002] Traditional polarization photodetectors primarily rely on the anisotropic absorption of materials to identify polarization by detecting changes in photocurrent intensity caused by the polarization direction of incident light. However, this mechanism based on light intensity differences has inherent limitations; polarization sensitivity and recognition accuracy are constrained by material properties and noise levels, making it difficult to meet the requirements of high-resolution polarization imaging.
[0003] In recent years, the polarization-sensitive photocurrent sign reversal effect has provided a new path for next-generation high-resolution polarization imaging. For example, polarization-related photocurrent reversal can be achieved through coupling structures of non-centrosymmetric metallic nanoantennas with half-metals or ferroelectric materials, but bottlenecks such as stringent antenna orientation design and complex fabrication processes remain. Summary of the Invention
[0004] The main objective of this application is to provide an infrared bipolar linearly polarized photodetector and its fabrication method. Based on the van der Waals heterostructure of black phosphorus (BP), molybdenum disulfide (MoS2), and graphene, the polarity of the graphene channel is controlled by the bottom grating, thereby achieving a bipolar linearly polarized detection effect in the infrared band where the sign of the photocurrent can be reversibly flipped with the polarization direction.
[0005] To achieve the above objectives, in a first aspect, this application proposes an infrared bipolar linearly polarized photodetector, comprising:
[0006] A silicon substrate constituting the detector gate has a silicon dioxide layer on its upper surface, and a first patterned body metal electrode and a second patterned body metal electrode are provided on a preset electrode pattern area of the silicon dioxide layer.
[0007] A graphene multilayer channel, wherein the two ends of the graphene multilayer channel are in close contact with the first patterned metal electrode and the second patterned metal electrode, respectively, to form the source and drain of the detector.
[0008] The upper surface of the graphene multilayer channel is further stacked with two-dimensional molybdenum disulfide and two-dimensional black phosphorus from bottom to top. Neither the two-dimensional molybdenum disulfide nor the two-dimensional black phosphorus is in contact with the first patterned metal electrode or the second patterned metal electrode.
[0009] In one embodiment, the thickness of the two-dimensional molybdenum disulfide is 5 nm, the thickness of the two-dimensional black phosphorus is 70 nm, and the thickness of the graphene multilayer channel is 3 nm.
[0010] In one embodiment, the silicon substrate is N-type heavily doped silicon, and the thickness of the silicon dioxide layer is 285 nm.
[0011] In one embodiment, both the first patterned body metal electrode and the second patterned body metal electrode are made of gold with a thickness of 50 nm, and are disposed on the preset electrode pattern area through a 5 nm titanium adhesion layer.
[0012] In one embodiment, the spacing between the first patterned body metal electrode and the second patterned body metal electrode is 40 to 60 μm.
[0013] Furthermore, to achieve the above objectives, in a second aspect, this application also proposes a method for fabricating an infrared bipolar linearly polarized photodetector, used to fabricate an infrared bipolar linearly polarized photodetector as described in any of the first aspects, comprising the following steps:
[0014] The silicon substrate with a silicon dioxide layer on its upper surface is cleaned and dried.
[0015] Electrode pattern regions are defined on a cleaned and dried silicon substrate using ultraviolet lithography.
[0016] A thermal evaporation technique is used to deposit a metal layer on the electrode pattern region as a first patterned metal electrode and a second patterned metal electrode.
[0017] Graphene multilayer channels, two-dimensional molybdenum disulfide, and two-dimensional black phosphorus were prepared by mechanical exfoliation.
[0018] The obtained graphene multilayer channel is transferred to a silicon substrate with a first patterned body metal electrode and a second patterned body metal electrode, so that the two ends of the graphene multilayer channel are in close contact with the first patterned body metal electrode and the second patterned body metal electrode, respectively.
[0019] Two-dimensional molybdenum disulfide and two-dimensional black phosphorus are stacked sequentially on the upper surface of the graphene multilayer channel.
[0020] In one embodiment, the method for cleaning and drying a silicon substrate with a silicon dioxide layer on its upper surface includes:
[0021] Acetone, anhydrous ethanol and deionized water were used as media in sequence to perform ultrasonic cleaning on the silicon substrate three times, with each ultrasonic cleaning time being 10 minutes.
[0022] The silicon substrate that has undergone ultrasonic cleaning is dried using a nitrogen stream.
[0023] Place the dried silicon substrate on a hot plate and bake at 100°C for 5 to 10 minutes.
[0024] In one embodiment, the method of depositing a metal layer on an electrode patterned region using thermal evaporation technology as a first patterned body metal electrode and a second patterned body metal electrode includes:
[0025] Using thermal evaporation technology, titanium and gold layers are sequentially deposited on the electrode pattern area, wherein the titanium layer constitutes the adhesion layer and the gold layer constitutes the first patterned bulk metal electrode and the second patterned bulk metal electrode.
[0026] Acetone, anhydrous ethanol, and deionized water were used sequentially as media to remove the photoresist left over from ultraviolet lithography.
[0027] In one embodiment, the method for preparing graphene multilayer channels, two-dimensional molybdenum disulfide, and two-dimensional black phosphorus using mechanical exfoliation further includes:
[0028] The graphene multilayer channels, two-dimensional molybdenum disulfide and two-dimensional black phosphorus prepared by mechanical exfoliation were transferred to the surface of polydimethylsiloxane elastomer, respectively.
[0029] This application provides an infrared bipolar linearly polarized photodetector and its fabrication method. The infrared bipolar linearly polarized photodetector uses graphene as the channel material, and stacks two-dimensional N-type semiconductor material molybdenum disulfide (MoS2) and anisotropic narrow bandgap two-dimensional material black phosphorus (BP) on it in sequence. By using the bottom grid to control the polarity of graphene, an infrared bipolar linearly polarized photodetector with reversible reversibility of photocurrent sign with polarization direction in the infrared band is realized. It has the advantages of simple structure, easy control, significant improvement of polarization recognition accuracy and signal-to-noise ratio, and potential for programmability and multi-functional integration. Attached Figure Description
[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 These are schematic diagrams of the structures of Embodiments 1 and 2 of the infrared bipolar linearly polarized photodetector in this application;
[0033] Figure 2 Example 2 of the infrared bipolar linearly polarized photodetector in this application is in V gA schematic diagram of the photocurrent response obtained after being irradiated by 3.5μm linearly polarized light at different polarization angles when Vds = 50V and Vds = 1V.
[0034] Figure 3 This is a flowchart illustrating Example 3 of the fabrication method for the infrared bipolar linearly polarized photodetector in this application.
[0035] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0036] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0037] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0038] Example 1
[0039] This embodiment provides an infrared bipolar linearly polarized photodetector, with reference to... Figure 1 ,include:
[0040] A silicon substrate constituting the detector gate has a silicon dioxide layer on its upper surface, and a first patterned body metal electrode and a second patterned body metal electrode are provided on a preset electrode pattern area of the silicon dioxide layer.
[0041] A graphene multilayer channel, wherein the two ends of the graphene multilayer channel are in close contact with the first patterned metal electrode and the second patterned metal electrode, respectively, to form the source and drain of the detector.
[0042] The upper surface of the graphene multilayer channel is further stacked with two-dimensional molybdenum disulfide and two-dimensional black phosphorus from bottom to top. Neither the two-dimensional molybdenum disulfide nor the two-dimensional black phosphorus is in contact with the first patterned metal electrode or the second patterned metal electrode.
[0043] Compared with existing technologies, the photocurrent reversal mechanism based on gate voltage control and polarization-induced reversal is more flexible in terms of structure and control method. It can achieve reversible switching of the transmission direction of photogenerated carriers by applying an external electric field, and can obtain photoelectric responses with opposite signs for different polarization states under the same device structure, thereby significantly improving polarization recognition accuracy and signal-to-noise ratio.
[0044] This mechanism possesses adjustability, programmability, and good compatibility, providing new physical support and implementation paths for the development of multifunctional integrated technologies such as polarization detection, intelligent sensing, and brain-like vision systems. It is of great significance for realizing the integration of sensing and computing and constructing high-performance artificial neural network vision chips.
[0045] This embodiment is based on the above mechanism, and on the van der Waals heterostructure of black phosphorus, molybdenum disulfide and graphene. The bipolar material graphene is used as the channel material, and two-dimensional n-type semiconductor material molybdenum disulfide (MoS2) and anisotropic narrow bandgap two-dimensional material black phosphorus (BP) are stacked on it in sequence. By controlling the polarity of the graphene channel through the bottom gate, a bipolar linear polarization detection effect with reversible flipping of photocurrent sign with polarization direction in the infrared band is realized, thereby realizing an infrared bipolar linear polarization photodetector.
[0046] This infrared bipolar linear polarization photodetector employs a stacked two-dimensional van der Waals heterostructure, eliminating the need for additional complex metal nano-antennas or ferropolar polarization structures. It achieves photocurrent sign reversal solely through electric field modulation and polarization induction, resulting in an infrared bipolar polarization detector with higher structural stability and better product consistency.
[0047] The bipolar response resulting from photocurrent sign reversal means that the device's response to different polarization directions is reflected not only in changes in light intensity but also in the complete reversibility of the current direction. This could potentially enable the realization of polarization ratios that cover all possible numbers. This feature enables high-contrast polarization imaging, providing a more reliable data foundation for infrared target recognition in complex scenarios and significantly improving polarization recognition accuracy and signal-to-noise ratio.
[0048] By controlling the gate voltage, different polarization ratios can be switched and selected within the same device structure, providing electrical programmability and laying the foundation for polarization-electric signal fusion detection and intelligent sensing functions. This principle can be extended to arrayed devices to achieve dynamic reconstruction and real-time processing of infrared polarization images, and has the potential to develop cutting-edge applications such as artificial vision systems and neuromorphic imaging chips.
[0049] Example 2
[0050] This embodiment is a further improvement on embodiment 1, and is similarly referred to... Figure 1In this embodiment, the thickness of the two-dimensional molybdenum disulfide (MoS2) is 5 nm, the thickness of the two-dimensional black phosphorus (BP) is 70 nm, and the thickness of the graphene multilayer channel is 3 nm.
[0051] Furthermore, the silicon substrate is N-type heavily doped silicon (n++Si), and the thickness of the silicon dioxide layer is 285nm.
[0052] Furthermore, both the first patterned body metal electrode and the second patterned body metal electrode are made of gold (Au) with a thickness of 50 nm, and are disposed on the preset electrode pattern area through a 5 nm titanium adhesion layer (not shown in the figure).
[0053] Furthermore, the spacing between the first patterned body metal electrode and the second patterned body metal electrode is 40 to 60 μm.
[0054] This embodiment provides a preferred implementation of a specific infrared bipolar linearly polarized photodetector, such as... Figure 2 As shown, in V g The schematic diagram shows the photocurrent response obtained after irradiation by 3.5μm linearly polarized light at different polarization angles at Vg=50V and Vds=1V. Under room temperature conditions, the photoelectric performance of an infrared bipolar linearly polarized photodetector was tested. When irradiated by linearly polarized light with an incident wavelength of 3.5μm, the photocurrent at a gate voltage of Vg=50V underwent a sign flip as the polarization angle changed, exhibiting a negative polarization ratio. Therefore, bipolar linearly polarized light detection was achieved. Figure 2 The horizontal axis represents time, and the vertical axis represents photocurrent.
[0055] Example 3
[0056] This embodiment provides a method for fabricating an infrared bipolar linearly polarized photodetector, used to prepare an infrared bipolar linearly polarized photodetector as shown in Embodiment 1 or Embodiment 2. Figure 3 As shown, it includes the following steps:
[0057] Step S1: Clean and dry the silicon substrate with a silicon dioxide layer on its upper surface;
[0058] Step S2: Define the electrode pattern region on the cleaned and dried silicon substrate using ultraviolet lithography.
[0059] Step S3: Using thermal evaporation technology, a metal layer is deposited on the electrode pattern area as the first patterned metal electrode and the second patterned metal electrode;
[0060] Step S4: Prepare graphene multilayer channels, two-dimensional molybdenum disulfide, and two-dimensional black phosphorus by mechanical exfoliation.
[0061] Step S5: Transfer the obtained graphene multilayer channel to a silicon substrate with a first patterned metal electrode and a second patterned metal electrode, so that the two ends of the graphene multilayer channel are in close contact with the first patterned metal electrode and the second patterned metal electrode, respectively.
[0062] Step S6: Stack two-dimensional molybdenum disulfide and two-dimensional black phosphorus sequentially on the upper surface of the graphene multilayer channel.
[0063] Optionally, the preparation of graphene multilayer channels, two-dimensional molybdenum disulfide and two-dimensional black phosphorus by mechanical exfoliation refers to repeatedly peeling off bulk crystals with tape until black phosphorus sheets, molybdenum disulfide sheets and graphene multilayers with the required thickness are obtained.
[0064] A high-precision two-dimensional material transfer platform can be used to transfer or stack black phosphorus flakes, molybdenum disulfide flakes, and graphene multilayers.
[0065] Compared with traditional methods that rely on nanoantennas, this embodiment significantly simplifies the fabrication process, improves repeatability, helps reduce fabrication costs, and further enhances the consistency of fabricated devices.
[0066] Example 4
[0067] This embodiment is an improvement on Embodiment 3, and taking the preparation of the infrared bipolar linearly polarized photodetector in Embodiment 2 as an example, further, in this embodiment, step S1 includes:
[0068] Step S101: Acetone, anhydrous ethanol and deionized water are used as media in sequence to perform ultrasonic cleaning on the silicon substrate three times, with each ultrasonic cleaning time being 10 minutes.
[0069] Step S102: Use nitrogen gas to dry the N-type heavily doped silicon substrate after ultrasonic cleaning;
[0070] Step S103: Place the dried N-type heavily doped silicon substrate on a hot plate and bake it at 100°C for 5 to 10 minutes.
[0071] By employing this embodiment, organic contaminants and particulate impurities on the surface of the silicon substrate can be effectively removed at low cost, so as to avoid the impurities affecting the definition of the electrode pattern area in step S2;
[0072] In step S2, the electrode pattern region is defined on the cleaned and dried silicon substrate using ultraviolet lithography, so that the deposited electrode regions maintain a spacing of 40-60μm.
[0073] Further, in this embodiment, step S3 includes:
[0074] Step S301: Using thermal evaporation technology, a 5nm titanium layer and a 50nm gold layer are sequentially deposited on the electrode pattern area as electrode layers.
[0075] Step S302: Acetone, anhydrous ethanol and deionized water are used sequentially as media to peel off the photoresist left by ultraviolet lithography.
[0076] Using this embodiment, patterned bulk metal electrodes with precise spacing and morphology can be obtained, which facilitates the alignment and transfer of subsequent two-dimensional materials. Due to the predefined electrode pattern region, the spacing between the two 50nm gold layers constituting the gold electrodes is 40-60μm.
[0077] Furthermore, in this embodiment, step S4 further includes:
[0078] The graphene multilayer channels, two-dimensional molybdenum disulfide and two-dimensional black phosphorus obtained by mechanical exfoliation were transferred to the surface of polydimethylsiloxane elastomer, respectively.
[0079] Specifically, in this embodiment, the bulk crystal is first peeled off repeatedly with tape until a black phosphorus sheet with a thickness of 70 nm, a molybdenum disulfide sheet with a thickness of 5 nm, and a graphene multilayer with a thickness of 3 nm are obtained. Then, the three sheets are transferred to the surface of polydimethylsiloxane elastomer to facilitate subsequent precise alignment and transfer operations.
[0080] Subsequently, using a high-precision two-dimensional material transfer platform, graphene multilayers were first transferred onto a substrate with patterned metal electrodes. Its two ends were aligned with two gold electrodes, making it in close contact with the gold electrodes as the source and drain of the device. Then, a molybdenum disulfide sheet was transferred onto the channel graphene multilayer without contacting the electrodes at both ends. Finally, a black phosphorus sheet was transferred onto the molybdenum disulfide sheet to form the final device structure. The N-type heavily doped silicon substrate served as the bottom gate of the device.
[0081] By adopting the above-described embodiments, the quality and consistency of the finished infrared bipolar linearly polarized photodetector can be further improved while ensuring that the preparation steps are simple and easy to repeat.
[0082] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.
Claims
1. An infrared bipolar linearly polarized photodetector, characterized in that, include: A silicon substrate constituting the detector gate has a silicon dioxide layer on its upper surface, and a first patterned body metal electrode and a second patterned body metal electrode are provided on a preset electrode pattern area of the silicon dioxide layer. A graphene multilayer channel, wherein the two ends of the graphene multilayer channel are in close contact with the first patterned metal electrode and the second patterned metal electrode, respectively, to form the source and drain of the detector. The upper surface of the graphene multilayer channel is further stacked with two-dimensional molybdenum disulfide and two-dimensional black phosphorus from bottom to top. Neither the two-dimensional molybdenum disulfide nor the two-dimensional black phosphorus is in contact with the first patterned metal electrode or the second patterned metal electrode.
2. The infrared bipolar linearly polarized photodetector as described in claim 1, characterized in that: The thickness of the two-dimensional molybdenum disulfide is 5 nm, the thickness of the two-dimensional black phosphorus is 70 nm, and the thickness of the graphene multilayer channel is 3 nm.
3. The infrared bipolar linearly polarized photodetector as described in claim 1, characterized in that: The silicon substrate is N-type heavily doped silicon, and the thickness of the silicon dioxide layer is 285 nm.
4. The infrared bipolar linearly polarized photodetector as described in claim 1, characterized in that: Both the first and second patterned metal electrodes are made of gold with a thickness of 50 nm, and are deposited on the preset electrode pattern area through a 5 nm titanium adhesion layer.
5. The infrared bipolar linearly polarized photodetector as described in claim 4, characterized in that: The spacing between the first patterned metal electrode and the second patterned metal electrode is 40 to 60 μm.
6. A method for fabricating an infrared bipolar linearly polarized photodetector, used to fabricate the infrared bipolar linearly polarized photodetector as described in any one of claims 1 to 5, characterized in that, Includes the following steps: The silicon substrate with a silicon dioxide layer on its upper surface is cleaned and dried. Electrode pattern regions are defined on a cleaned and dried silicon substrate using ultraviolet lithography. A thermal evaporation technique is used to deposit a metal layer on the electrode pattern region as a first patterned metal electrode and a second patterned metal electrode. Graphene multilayer channels, two-dimensional molybdenum disulfide, and two-dimensional black phosphorus were prepared by mechanical exfoliation. The obtained graphene multilayer channel is transferred to a silicon substrate with a first patterned body metal electrode and a second patterned body metal electrode, so that the two ends of the graphene multilayer channel are in close contact with the first patterned body metal electrode and the second patterned body metal electrode, respectively. Two-dimensional molybdenum disulfide and two-dimensional black phosphorus are stacked sequentially on the upper surface of the graphene multilayer channel.
7. The method for fabricating an infrared bipolar linearly polarized photodetector as described in claim 6, characterized in that, The method for cleaning and drying a silicon substrate with a silicon dioxide layer on its upper surface includes: Acetone, anhydrous ethanol and deionized water were used as media in sequence to perform ultrasonic cleaning on the silicon substrate three times, with each ultrasonic cleaning time being 10 minutes. The silicon substrate that has undergone ultrasonic cleaning is dried using a nitrogen stream. Place the dried silicon substrate on a hot plate and bake at 100°C for 5 to 10 minutes.
8. The method for fabricating an infrared bipolar linearly polarized photodetector as described in claim 6, characterized in that, The method of depositing a metal layer on an electrode pattern region using thermal evaporation technology as a first patterned body metal electrode and a second patterned body metal electrode includes: Using thermal evaporation technology, titanium and gold layers are sequentially deposited on the electrode pattern area, wherein the titanium layer constitutes the adhesion layer and the gold layer constitutes the first patterned bulk metal electrode and the second patterned bulk metal electrode. Acetone, anhydrous ethanol, and deionized water were used sequentially as media to remove the photoresist left over from ultraviolet lithography.
9. The method for fabricating an infrared bipolar linearly polarized photodetector as described in claim 6, characterized in that, The method for preparing graphene multilayer channels, two-dimensional molybdenum disulfide, and two-dimensional black phosphorus using mechanical exfoliation further includes: The graphene multilayer channels, two-dimensional molybdenum disulfide and two-dimensional black phosphorus prepared by mechanical exfoliation were transferred to the surface of polydimethylsiloxane elastomer, respectively.