A two-dimensional semiconductor ferroelectric gate transistor structure photoelectric detection device based on oxygen plasma treatment

Abstract

A two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment belongs to the field of photoelectric detection technology. Using silicon / silicon dioxide as a substrate, the two-dimensional ferroelectric semiconductor material α-In₂Se₃ is placed on the silicon dioxide. An interfacial insulating dielectric layer is formed on the surface of the α-In₂Se₃ material after oxygen plasma treatment. A two-dimensional transition metal chalcogenide is prepared on the insulating dielectric layer using a mechanical exfoliation method. Metal electrodes are bonded to the two-dimensional ferroelectric semiconductor material and the two-dimensional transition metal chalcogenide through electrode adhesion layers. Under the action of the two-dimensional ferroelectric gate, the device exhibits photoelectric detection performance with low dark current and high responsivity. The device also has a certain optical memory function, making it suitable for multifunctional devices integrating detection and memory. The gate dielectric layer preparation method of this invention is simple, suitable for large-scale preparation, and low in cost. It can be applied to the fields of photoelectric detection technology and artificial vision bionics.

Description

Technical fields:

[0001] This invention relates to the field of photodetector technology, specifically to a two-dimensional semiconductor ferroelectric gate transistor structure photodetector device treated with oxygen plasma. Background technology:

[0002] Photodetectors, as the most basic device unit for converting light signals into electrical signals, have a wide range of applications. They are currently widely used in optical communication, laser ranging, tracking, guidance, automatic control, and in military and civilian products such as laser disc players, barcode readers, computer light pens, and even game consoles. Among these, traditional semiconductor material detectors based on silicon and III-V compounds are leaders in commercial photodetectors due to their variety, wide spectral range, and high quantum efficiency. However, with the advent of the information age, the application requirements for third-generation photodetectors have shifted towards smaller size, lighter weight, higher performance, lower cost, and lower power consumption. Traditional semiconductor detectors, which require low temperatures, no longer meet current application demands in terms of cost, size, and performance. Two-dimensional materials with atomic-layer thickness have natural advantages, and ultrathin two-dimensional materials, due to the strong optical field coupling caused by quantum confinement, have extremely high light absorption efficiency, making them one of the most promising materials for third-generation photodetectors. However, the ultrathin nature of two-dimensional materials also leads to drawbacks such as high transparency and limited photoresponsivity. To improve responsivity, constructing gate-controlled field-effect transistor structures on the device surface is the simplest and most effective method. However, currently widely used gate dielectric materials are still mainly traditional three-dimensional materials (such as SiO2 and Al2O3). These traditional materials generate large leakage currents when their size is reduced to the atomic level, which cannot meet the requirements of two-dimensional device applications. Two-dimensional gate dielectric material h-BN has also been discovered, but as an insulating gate material, its function is limited, lacking scalability for multi-functional applications such as amplifying photoelectric signals and integrating detection and memory. This inability to meet the growing demand for multi-functionality in single devices restricts the application of two-dimensional material photodetectors in next-generation optoelectronics. Therefore, designing a transistor structure photodetector composed of pure two-dimensional materials suitable for multi-functional applications is of significant importance and application value. Summary of the Invention:

[0003] This invention provides a two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment, wherein the preparation method of the gate dielectric layer based on oxygen plasma treatment is simple, the device is easy to fabricate, and the cost is low.

[0004] A photodetector device based on a two-dimensional semiconductor ferroelectric gate transistor structure processed by oxygen plasma is characterized in that a strip-shaped two-dimensional ferroelectric semiconductor material (2) is prepared on a substrate (1), and an interface insulating dielectric layer (3) is formed on the strip-shaped two-dimensional ferroelectric semiconductor material (2); a strip-shaped two-dimensional transition metal chalcogenide material (4) is also prepared on the substrate (1), and the strip-shaped two-dimensional transition metal chalcogenide material (4) and the strip-shaped two-dimensional ferroelectric semiconductor material (2) intersect at a cross, and the transition metal chalcogenide material (4) is located on the ferroelectric semiconductor material (2) at the intersection and there is an interface insulating dielectric layer (3) between the transition metal chalcogenide material (4) and the ferroelectric semiconductor material (2); independent metal electrodes (5) are prepared at both ends of the strip-shaped two-dimensional ferroelectric semiconductor material (2), and independent metal electrodes (5) are prepared at both ends of the strip-shaped two-dimensional transition metal chalcogenide material (4).

[0005] The device is a ferroelectric gate transistor structure photodetector constructed from a two-dimensional ferroelectric material and a two-dimensional transition metal chalcogenide (using molybdenum diselenide as an example) processed by oxygen plasma. From bottom to top, it comprises: a substrate, a two-dimensional ferroelectric semiconductor material, an interface insulating dielectric layer, a two-dimensional transition metal chalcogenide, and a metal electrode.

[0006] In the above scheme, the substrate is silicon / silicon dioxide, that is, there is silicon dioxide as an insulating layer on the silicon surface, and the silicon dioxide is used to isolate the charge injection of the silicon substrate; the silicon dioxide layer is obtained by in-situ thermal oxidation on silicon, and the thickness is 280-300nm.

[0007] In the above scheme, the two-dimensional ferroelectric semiconductor material selected is α-In2Se3. α-In2Se3 is a two-dimensional semiconductor material that can be polarized by an electric field. The thickness of the strip-shaped two-dimensional transition metal chalcogenide material (4) is 5-60nm.

[0008] In the above scheme, the interface insulating dielectric layer (3) is obtained by irradiating the two-dimensional ferroelectric semiconductor material α-In2Se3 with oxygen plasma; under oxygen plasma irradiation, the α-In2Se3 on the surface can be transformed into In2Se. 3-x O x The oxygen plasma irradiation power is 50-80W, and the irradiation time is 10-20min;

[0009] In the above scheme, the two-dimensional transition metal chalcogenide can be selected from molybdenum diselenide, tungsten diselenide, etc., and the thickness of the strip-shaped two-dimensional transition metal chalcogenide material (4) is 0.6-10nm.

[0010] In the above scheme, the metal electrode is a common inert metal with an adhesion layer, such as: the electrode adhesion layer is 5-10nm titanium adhesion, and the electrode is gold with a thickness of 50-80nm.

[0011] The device fabrication process in this invention specifically includes the following steps:

[0012] (1) Clean the silicon substrate with an in-situ thermally oxidized silicon dioxide layer on the surface using acetone, isopropanol, deionized water, etc.

[0013] (2) By using mechanical stripping, a strip-shaped two-dimensional ferroelectric semiconductor material is obtained on a silicon substrate (2), that is, a wide strip-shaped α-In2Se3 layer is obtained;

[0014] (3) The α-In2Se3 layer was irradiated using an oxygen plasma etching machine to form In2Se on the surface. 3-x O x The oxygen plasma irradiation power is 50-80W, and the irradiation time is 10-20min;

[0015] (4) Using mechanical stripping, a strip of two-dimensional transition metal chalcogenide material (4) of appropriate size is stacked in situ on the silicon substrate treated with oxygen plasma in step (3), such as molybdenum diselenide, so that the strip of two-dimensional transition metal chalcogenide material (4) and the strip of two-dimensional ferroelectric semiconductor material (2) are cross-shaped.

[0016] (5) The pattern corresponding to the metal electrode is obtained by using processes including spin coating of photoresist, ultraviolet exposure, and development;

[0017] (6) A 5-10 nm thick titanium adhesion layer and a 50-80 nm gold electrode deposition layer are prepared by electron beam evaporation, and a lift-off process is performed to obtain the ferroelectric gate transistor structure photodetector device.

[0018] The beneficial effects of the graphene-molybdenum disulfide lateral heterostructure detector of the present invention are as follows:

[0019] The two-dimensional ferroelectric semiconductor material α-In₂Se₃ in this invention is a two-dimensional layered ferroelectric semiconductor material. Even when thinned to atomic layers, this material can still be polarized and maintain its polarization characteristics under an electric field. It has excellent application prospects for multifunctional applications such as integrated sensing and storage in two-dimensional optoelectronic devices. The application of two-dimensional semiconductor ferroelectric gate transistor structure photodetectors based on oxygen plasma treatment can also be used as optical memory.

[0020] The two-dimensional ferroelectric material α-In2Se3 in this invention changes its polarization intensity under illumination. This light-tunable two-dimensional ferroelectric gate regulates the carrier concentration in the two-dimensional transition metal chalcogenide channel material, enabling the device to have high photoresponsivity.

[0021] The two-dimensional ferroelectric material In2Se treated with oxygen plasma in this invention 3-x O x It has a wider bandgap than the original α-In₂Se₃ and can be used as a charge blocking layer to prevent charge injection from the ferroelectric semiconductor α-In₂Se₃ into the channel material, which is a two-dimensional transition metal chalcogenide. This can reduce the dark current of the photodetector.

[0022] The In2Se gate dielectric layer of the device in this invention 3-x O x The method of preparation by oxygen plasma irradiation is simple, the device preparation is easy and the cost is low. Attached image description:

[0023] Figure 1 This is a schematic diagram of the device structure described in this invention.

[0024] Figure 2 This is a schematic diagram of the circuit wiring and optical detection of the device described in this invention.

[0025] The labels in the attached figure are: 1-substrate; 2-two-dimensional ferroelectric semiconductor material; 3-interface insulating dielectric layer; 4-two-dimensional transition metal chalcogenide; 5-metal electrode.

[0026] Figure 3 The diagram shows the transfer curve and ferroelectric grid leakage current test results of the device described in this invention.

[0027] Figure 4 This is a comparison chart of the transfer curves of the device described in this invention under no light and under illumination.

[0028] Figure 5 This is a test diagram of the photocurrent switching of the device described in this invention under reverse gate voltage.

[0029] Figure 6 This is a photocurrent switching test diagram of the device described in this invention under forward gate voltage.

[0030] Figure 7 This is a test diagram of the optical memory characteristics of the device described in this invention. Detailed implementation method:

[0031] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0032] Example 1:

[0033] Figure 1The diagram shows a schematic of a two-dimensional semiconductor ferroelectric gate transistor photodetector based on oxygen plasma treatment according to the present invention. The photodetector includes at least 1-a silicon / silicon dioxide substrate, 2-a two-dimensional ferroelectric semiconductor material α-In₂Se₃, 3-an interface insulating dielectric layer, 4-a two-dimensional transition metal chalcogenide, and 5-a metal electrode. The silicon / silicon dioxide substrate is approximately 500 micrometers thick, with the thermally oxidized silicon dioxide layer being 280 nm thick. Before preparing the 2-two-dimensional ferroelectric semiconductor material α-In₂Se₃, the substrate surface is cleaned using conventional silicon substrate cleaning methods. The 2-two-dimensional ferroelectric semiconductor material α-In₂Se₃ is obtained by mechanical exfoliation and has a thickness of approximately 30 nm. The 3-interface insulating dielectric layer is prepared by placing the exfoliated α-In₂Se₃ in an oxygen plasma etching machine, introducing oxygen into the etching machine, and irradiating the surface of the 2-two-dimensional ferroelectric semiconductor material α-In₂Se₃ with an ionization power of 60 W. The molybdenum diselenide (4-Mo) is similar to the two-dimensional ferroelectric semiconductor material α-In₂Se₃, and is also obtained using a mechanical exfoliation method, with a thickness of approximately 5 nm. The five metal electrodes with adhesion layers are deposited on the α-In₂Se₃ and Molybdenum diselenide materials, respectively, and the final lateral heterojunction photodetector is obtained through standard photolithography, development, electron beam evaporation, and lift-off processes. By connecting the detector to external leads, source meters, and other devices, electrical performance testing can be performed.

[0034] Figure 2 The diagram shows the circuit wiring and photodetector schematic of a two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma processing according to the present invention. Either metal electrode at the α-In₂Se₃ end is used as the gate electrode, and the metal electrodes at both ends of molybdenum diselenide are used as the source and drain electrodes, respectively.

[0035] The gate leakage current of the two-dimensional ferroelectric gate transistor structure photodetector in this invention is less than 1 pA, see appendix. Figure 3 The device's light-to-dark current ratio is close to 10. 5 See attached Figure 5 .

[0036] The two-dimensional ferroelectric gate transistor structure photodetector of this invention has a certain memory function for the photocurrent under forward gate voltage, as shown in the appendix. Figure 6 .

[0037] The two-dimensional ferroelectric gate transistor structure photodetector embodiment in this invention is only used to illustrate the advantages and features of the detector structure of this invention, and is not intended to limit the scope of this invention.

Claims

1. A two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment, characterized in that, A strip-shaped two-dimensional ferroelectric semiconductor material (2) is prepared on a substrate (1), and an interface insulating dielectric layer (3) is formed on the strip-shaped two-dimensional ferroelectric semiconductor material (2); a strip-shaped two-dimensional transition metal chalcogenide material (4) is also prepared on the substrate (1), and the strip-shaped two-dimensional transition metal chalcogenide material (4) and the strip-shaped two-dimensional ferroelectric semiconductor material (2) intersect at a cross, and the transition metal chalcogenide material (4) is located on the ferroelectric semiconductor material (2) at the intersection, and there is an interface insulating dielectric layer (3) between the transition metal chalcogenide material (4) and the ferroelectric semiconductor material (2); independent metal electrodes (5) are prepared at both ends of the strip-shaped two-dimensional ferroelectric semiconductor material (2), and independent metal electrodes (5) are prepared at both ends of the strip-shaped two-dimensional transition metal chalcogenide material (4); The two-dimensional ferroelectric semiconductor material is α-In2Se3; the interface insulating dielectric layer (3) is obtained by irradiating the two-dimensional ferroelectric semiconductor material α-In2Se3 with oxygen plasma; under oxygen plasma irradiation, the α-In2Se3 on the surface is transformed into In2Se. 3-x O x The oxygen plasma irradiation power is 50-80 W, and the irradiation time is 10-20 min.

2. A two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma processing according to claim 1, characterized in that, The substrate is silicon / silicon dioxide, with silicon dioxide as an insulating layer on the silicon surface. The silicon dioxide is used to isolate the charge injection into the silicon substrate. The silicon dioxide layer is obtained by in-situ thermal oxidation on silicon and has a thickness of 280-300 nm.

3. A two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment according to claim 1, characterized in that, α-In2Se3 is a two-dimensional semiconductor material that can be polarized by an electric field. The strip-shaped two-dimensional transition metal chalcogenide material (4) has a thickness of 5-60 nm.

4. A two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma processing according to claim 1, characterized in that, Two-dimensional transition metal chalcogenides, selected from molybdenum diselenide and tungsten diselenide, strip-shaped two-dimensional transition metal chalcogenide materials (4) with a thickness of 0.6-10 nm.

5. A two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment according to claim 1, characterized in that, The metal electrode is an inert metal with an adhesive layer.

6. A two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment according to claim 5, characterized in that, The electrode adhesion layer is made of titanium with a thickness of 5-10 nm, and the electrode is made of gold with a thickness of 50-80 nm.

7. A method for room-temperature fabrication of a two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment, as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Clean the silicon substrate with an in-situ thermally oxidized silicon dioxide layer on the surface with acetone, isopropanol and deionized water; (2) Using mechanical stripping, a strip-shaped two-dimensional ferroelectric semiconductor material (2) is obtained on a silicon substrate, resulting in a wide strip-shaped α-In2Se3 layer; (3) The α-In2Se3 layer was irradiated using an oxygen plasma etching machine to form In2Se on the surface. 3-x O x The oxygen plasma irradiation power is 50-80 W, and the irradiation time is 10-20 min; (4) Using mechanical stripping, a strip of two-dimensional transition metal chalcogenide material (4) of appropriate size is stacked in situ on the silicon substrate treated with oxygen plasma in step (3), so that the strip of two-dimensional transition metal chalcogenide material (4) and the strip of two-dimensional ferroelectric semiconductor material (2) intersect in a cross shape. (5) The pattern corresponding to the metal electrode is obtained by using a process including spin coating of photoresist, ultraviolet exposure and development; (6) A 5-10 nm thick titanium adhesion layer and a 50-80 nm gold electrode deposition layer are prepared by electron beam evaporation, and a lift-off process is performed to obtain the ferroelectric gate transistor structure photodetector device.

8. The application of the two-dimensional semiconductor ferroelectric gate transistor structure photodetector based on oxygen plasma treatment as described in any one of claims 1-6, as an optical memory.

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