A three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector and preparation method thereof

Abstract

The present invention discloses a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector and a preparation method. The photodetector comprises: a silicon layer, an insulating dielectric layer is arranged on the silicon layer, the insulating dielectric layer and the silicon layer have concentric grooves, a top electrode is arranged above the insulating dielectric layer, and a bottom contact electrode is arranged below the silicon layer; a three-dimensional silicon nanostrip is arranged in the groove on the silicon layer and connected to the silicon layer; a macroscopically assembled graphene is arranged above and directly in contact with the top electrode and the insulating dielectric layer, and contacts with the three-dimensional silicon nanostrip to form a Schottky junction; the portion located in the groove area of ​​the insulating dielectric layer is patterned to form a macroscopically assembled graphene nanostrip. In the field of photoelectric detection technology, the present invention realizes the composite of macroscopically assembled graphene nanostructures and silicon nanostructures for the first time, solving the problem that the existing silicon-based graphene photodetector has weak detection performance in an ultra-wide spectral range, especially in the infrared band.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric detection, and relates to a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector and a preparation method thereof. Background Art

[0002] With the progress of society and the development of science and technology, there is a wide range of application demands for photodetectors that respond to ultraviolet, visible light, and infrared in the fields of cameras, medical treatment, security, national defense, and military. In recent years, silicon-based photodetectors and image sensors have played a vital role in promoting the rapid development of the information age. Among them, broadband spectrum detection is crucial to the future development of the information society. From ultraviolet to infrared, broadband spectrum detection not only provides valuable visual and imaging information, but also helps to analyze internal structure and composition. Its application areas include machine vision, unmanned driving, environmental monitoring, space remote sensing, and cultural relics protection. However, traditional Si photodetectors are limited by the inherent band gap of Si, which limits their spectral response range and hinders them from meeting the urgent needs of future Si-based intelligent cognitive chips for broadband spectrum detection. Therefore, combining new materials and new structures with silicon technology is the key to achieving broadband spectrum detection.

[0003] A Chinese patent application with publication number CN110611010B discloses a silicon nanocrystal / graphene wide-spectrum photodetector and a method for preparing the same. The patent mentions that the photoinduced switching effect between the silicon nanocrystal layer and the graphene layer is used to achieve signal multiplication to achieve response to the ultraviolet, visible and near-infrared optical spectrum ranges. However, it is limited to the limited absorption rate of light by a single-layer graphene (a single layer is only 2.3%), the temperature rise of the electronic system is limited, and the number of hot electrons distributed in the high-energy region is small, which is insufficient to achieve the collection and utilization of long-wavelength light far below the potential barrier, greatly limiting the utilization efficiency of the optoelectronic device for long-wavelength light.

[0004] Taking advantage of the relatively simple mass production and preparation of silicon-based chip-scale heterogeneous integration technology, the development of silicon-based intelligent broadband spectrum recognition chips has become the focus of future semiconductor technology development. The integration of large-area graphene with silicon prepared by chemical vapor deposition and macroscopic self-assembly will help overcome the detection bottleneck of traditional silicon-based devices and has important research significance.

[0005] A Chinese patent application with publication number CN111739963B discloses a method for preparing a silicon-based wide-spectrum photodetector. The patent mentions that wide-spectrum detection from visible light to infrared light can be achieved by forming an n-type / p-type double-layer PbS colloidal quantum dot on the surface of a silicon-based passivation layer. However, due to the uneven distribution of the quantum dots themselves, large-area on-chip integration cannot be effectively achieved, and the absorption of the combination of the two materials alone is generally weak in a wide spectral range. Secondly, the solution used to process the quantum dots has a certain toxicity, which is not conducive to health and environmental protection.

[0006] A Chinese patent application with publication number CN105720197B discloses a self-driven wide spectral response silicon-based hybrid heterojunction photoelectric sensor and a method for preparing the same. The patent mentions that wide spectral detection can be achieved by forming a three-dimensional heterojunction contact between silicon nanowires and organic polymer semiconductor films. However, since only silicon nanowires play a major absorption role, the device can only achieve a spectral response within the range of 300nm-1100nm, limiting the overall detection efficiency of the device.

[0007] The present invention can be integrated on-chip, and for the first time realizes the composite of macroscopically assembled graphene nanostructures and silicon nanostructures, solving the problem of weak detection performance of existing silicon-based graphene photodetectors in an ultra-wide spectral range, especially in the infrared band, and can work at room temperature without refrigeration, which is a huge breakthrough for infrared band detection. Secondly, it can also work without bias voltage, which is expected to bring extremely low energy consumption or even zero energy consumption, and has the advantage of low energy consumption. For this reason, the inventor proposed the present invention. Summary of the invention

[0008] The purpose of the present invention is to address the deficiencies in the prior art and provide a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector and a preparation method, which for the first time realizes the composite of macroscopically assembled graphene nanostructures and silicon nanostructures, and solves the problem that the existing silicon-based graphene photoelectric detectors have weak detection performance in an ultra-wide spectral range, especially in the infrared band.

[0009] The object of the present invention is achieved through the following technical solution: a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector, the photoelectric detector comprising:

[0010] A silicon layer, on which an insulating dielectric layer is arranged, the insulating dielectric layer and the silicon layer have concentric grooves, a top electrode is arranged above the insulating dielectric layer, and a bottom contact electrode is arranged below the silicon layer;

[0011] a three-dimensional silicon nanoribbon disposed in a groove on the silicon layer and connected to the silicon layer;

[0012] The macroscopically assembled graphene is disposed above and in direct contact with the top electrode and the insulating dielectric layer, and is in contact with the three-dimensional silicon nanostrip to form a Schottky junction; the portion located in the groove area of ​​the insulating dielectric layer is patterned to form a macroscopically assembled graphene nanostrip.

[0013] Furthermore, the groove of the insulating dielectric layer is a perforated groove, and the top electrode is disposed above the insulating dielectric layer and arranged with the perforated groove of the insulating dielectric layer as the center.

[0014] Furthermore, the perforated grooves of the insulating dielectric layer are polygonal grooves or circular grooves; the distribution of the top electrode with the perforated grooves of the insulating dielectric layer as the center is any one of a quadrangular distribution, a herringbone distribution or a plum blossom distribution; the insulating dielectric layer is any one of silicon dioxide, silicon nitride, boron nitride, silicon oxynitride, aluminum oxide or rutile titanium dioxide; the preparation process of the insulating dielectric layer is any one of thermal oxidation growth, plasma enhanced chemical vapor deposition PECVD furnace growth, atomic layer deposition ALD or electron beam evaporation deposition of silicon oxide.

[0015] Furthermore, the three-dimensional silicon nanoribbons and the macroscopically assembled graphene nanoribbons are composited based on heterogeneous metamaterials to achieve high-performance detection of ultra-wide spectrum from deep ultraviolet to visible light to near infrared bands.

[0016] Furthermore, when radiation photons enter the photodetector, by utilizing the multilayer structure of the macroscopically assembled graphene and the composite structure design with the three-dimensional silicon nanoribbon and the macroscopically assembled graphene nanoribbon, both nanoribbons will cooperatively absorb the photons to excite radiation electrons, and the generated photogenerated electron-hole pairs will be separated under the action of an external bias voltage, and finally collected by the electrodes at both ends. The excited radiation electrons will collide with bound electrons during the process of traveling between the layers of the macroscopically assembled graphene nanoribbon and the three-dimensional silicon nanoribbon and in the vertical transmission direction, and the collided electrons will continue to collide with other bound electrons, and the collected light response can reflect the radiation energy of the incident particles.

[0017] When an external bias is applied, the radiated electrons and the impacted electrons trigger the photoelectric effect when they reach the macroscopically assembled graphene / semiconductor interface. By reading the response current, the radiation signal and intensity are read out in real time. Open-circuit voltage and short-circuit current are generated by light without the need for external power supply. The light itself enables the device to operate at room temperature and detect the infrared band.

[0018] Furthermore, the preparation of the three-dimensional composite nanoribbon structure is specifically as follows: using a nanoribbon metal mask, an inductively coupled plasma dry etching system ICP is used to etch the macroscopically assembled graphene film, and firstly a patterned macroscopically assembled graphene nanoribbon is prepared; using a nanoribbon metal mask, ICP etching is performed again to obtain the three-dimensional silicon nanoribbon; at 200°C, chlorine gas is used to remove the surface nanoribbon metal mask, and finally a three-dimensional composite nanoribbon structure composed of a three-dimensional silicon strip nanostructure and macroscopically assembled graphene nanoribbons is obtained; the structural unit graphic design of the macroscopically assembled graphene nanoribbons and the three-dimensional silicon nanoribbons is as follows: a square nanoblock structure is connected between every two rectangular nanoribbons, and the overall structure is axially symmetrical.

[0019] Furthermore, the macroscopically assembled graphene is a multilayer graphene nanofilm with consistent crystal stacking angles, or a macroscopically assembled graphene nanofilm doped with bromine, molybdenum chloride, copper chloride or molybdenum disulfide; the macroscopically assembled graphene is prepared by mechanical exfoliation, suction sintering or chemical vapor deposition, and has a thickness of 30 to 60 nm.

[0020] Furthermore, the material of the silicon layer and the three-dimensional silicon nanostrips can be replaced by any one of germanium, indium gallium arsenide, gallium arsenide, cadmium telluride, indium phosphide, silicon carbide or gallium nitride.

[0021] Furthermore, the bottom contact electrode is any one of gallium-indium alloy, metal silicide or metal aluminum, and is used for ohmic contact between the silicon layer and the top electrode; the material of the top electrode is any one of gold, aluminum, platinum, titanium-gold alloy, chromium-gold alloy or indium tin oxide; the deposition process of the top electrode is any one of thermal evaporation, electron beam evaporation or magnetron sputtering.

[0022] On the other hand, the present invention also provides a method for preparing a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector, the method comprising the following steps:

[0023] (1) Preparation of silicon substrate: Cut the silicon wafer into the required size, clean the surface, and ultrasonically clean it in acetone, isopropanol, and deionized water solution in sequence, then take it out and blow dry it with nitrogen;

[0024] (2) Patterning of the top electrode: Spin-coat the cleaned silicon wafer with photoresist so that the photoresist evenly covers the surface of the silicon wafer, then perform pre-baking, photolithography and development operations, and metal deposition operations. Then use acetone to strip off the remaining metal except the electrode pattern, and then clean the acetone with isopropyl alcohol to obtain a complete electrode pattern;

[0025] (3) Patterning of silicon windows: Repeat the steps of photoresist coating-pre-baking-photolithography-development in step (2) to completely solidify the photoresist and protect the oxide layer under the photoresist during wet etching; then, etch the oxide layer of the window area not protected by the photoresist in a buffered oxide etching BOE solution. After removing the device from the BOE solution, wash it in water, and then remove the photoresist with acetone and isopropyl alcohol to complete the patterning of the silicon window;

[0026] (4) Transfer of macro-assembled graphene: A redox graphene film is prepared on a porous nano-alumina template (AAO) by a filtration method, and a macro-assembled graphene film is formed after sintering; the transfer method of the macro-assembled graphene film is as follows: a mixture of ethanol and deionized water is dripped onto the top electrode and the silicon window, and then a small piece of the macro-assembled graphene film is torn off and evenly spread on the mixed liquid ball drop, and then the mixed liquid is blown away with argon gas, so that the macro-assembled graphene film area evenly covers the silicon window and the top electrode area and is in close contact with them;

[0027] (5) Preparation of nano-strip metal mask: the silicon wafer after the above process is coated with photoresist, and electron beam photoresist is spin-coated and dried; after exposure, an inverted trapezoidal structure is formed; electron beam lithography is performed on the thin film material after spin coating; metal is evaporated by electron beam on the surface of the photolithography pattern; aluminum on the part with electron beam photoresist is removed, and then ICP etching is performed to photolithograph the designed nano-strip pattern, metal is deposited by electron beam evaporation, and acetone is peeled off to obtain a nano-strip metal mask;

[0028] (6) Preparation of three-dimensional composite nanostructures: Using a nanostrip metal mask, ICP is used to etch the macroscopically assembled graphene film to prepare a patterned macroscopically assembled graphene nanostrip; using the nanostrip metal mask, ICP etching is performed again to obtain a three-dimensional silicon strip nanostructure, and chlorine gas is used to remove the surface nanostrip metal mask to finally obtain a three-dimensional composite nanostructure consisting of a three-dimensional silicon strip nanostructure and macroscopically assembled graphene nanostrips;

[0029] (7) Preparation of bottom contact electrode: A bottom contact electrode is fabricated on the back side of the silicon of the above device to establish ohmic contact between the bottom contact electrode and the top electrode.

[0030] Beneficial effects of the invention: The invention can be integrated on-chip, and for the first time realizes the composite of macroscopically assembled graphene nanostructures and silicon nanostructures, solving the problem of weak detection performance of existing silicon-based graphene photodetectors in an ultra-wide spectral range, especially in the infrared band, and can work at room temperature without refrigeration, which is a huge breakthrough for infrared band detection. Secondly, it can also work without bias voltage, which is expected to bring extremely low energy consumption or even zero energy consumption, and has the advantage of low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 Schematic diagram of an isotropic three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector provided by the present invention.

[0033] Figure 2 An enlarged view of local details of a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector provided by the present invention.

[0034] Figure 3 This is a comparison diagram of the absorption spectra of the present invention and ordinary single-layer graphene or macroscopically assembled graphene.

[0035] Figure 4 A preparation flow chart of a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector provided by the present invention.

[0036] Figure 5 The photocurrent and photoresponsivity test diagrams of the present invention and ordinary single-layer graphene silicon-based photodetectors in the ultraviolet, visible light, and near-infrared bands.

[0037] Figure 6 This is an optical photograph of the 8 × 8 array detector after array preparation according to the present invention.

[0038] Figure 7 It is a schematic diagram of the setting of the imaging method after array preparation of the present invention and real-time grayscale imaging of a wide spectrum.

[0039] in:

[0040] 1. Three-dimensional silicon nanoribbons, 2. Macroscopically assembled graphene nanoribbons, 3. Macroscopically assembled graphene, 4. Top electrode, 5. Insulating dielectric layer, 6. Silicon layer, 7. Bottom contact electrode. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the accompanying drawings and implementation examples. It should be understood that the specific implementation examples described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] like Figure 1As shown, the present invention provides a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector, including three-dimensional silicon nanostrips 1, macroscopically assembled graphene nanostrips 2, macroscopically assembled graphene 3, top electrodes 4, insulating dielectric layers 5, silicon layers 6, bottom contact electrodes 7 and other components.

[0043] The insulating dielectric layer 5 is arranged above the silicon layer 6, and together they constitute the device body; the insulating dielectric layer 5 and the silicon layer 6 are provided with concentric grooves, wherein the grooves of the insulating dielectric layer 5 are perforated grooves, and the three-dimensional silicon nanostrip 1 is arranged in the grooves of the silicon layer and connected to the silicon layer; the top electrode 4 is arranged above the insulating dielectric layer 5 and arranged with the perforated grooves of the insulating dielectric layer 5 as the center; the macroscopically assembled graphene 3 is arranged above the top electrode 4 and the insulating dielectric layer 5 and is in direct contact with the three-dimensional silicon nanostrip 1 to form a Schottky junction, and the macroscopically assembled graphene nanostrip 2 is obtained by patterning the macroscopically assembled graphene 3 region distributed in the perforated groove region of the insulating dielectric layer 5, and the bottom contact electrode 7 is arranged below the silicon layer 6 to be used for ohmic contact between the silicon layer 6 and the top electrode 4;

[0044] The macroscopically assembled graphene 3 is a multilayer graphene nanofilm with a consistent crystal stacking angle, and can also be a macroscopically assembled graphene nanofilm doped with bromine, molybdenum chloride, copper chloride or molybdenum disulfide. The macroscopically assembled graphene 3 is prepared by mechanical stripping, suction sintering or chemical vapor deposition, and its thickness can be 30 to 60 nm. The material of the silicon layer 6 and the three-dimensional silicon nanoribbon 1 can be any one of silicon, germanium, indium gallium arsenide, gallium arsenide, cadmium telluride, indium phosphide, silicon carbide or gallium nitride. The silicon material in the present invention is one of the examples cited.

[0045] The bottom contact electrode 7 may be any one of gallium-indium alloy (Ga-In), metal silicide (NiSi, TiSi2 or CoSi2) or metal aluminum, and is used as the silicon layer 6 to make ohmic contact with the top electrode 4. The material of the top electrode 4 may be any one of gold, aluminum, platinum, titanium-gold alloy, chromium-gold alloy or indium tin oxide. The deposition process of the top electrode 4 may be any one of thermal evaporation, electron beam evaporation or magnetron sputtering.

[0046] The perforated groove of the insulating dielectric layer 5 can be any one of a rectangular groove, a plum blossom groove, a triangular groove or a circular groove. The distribution of the top electrode 4 centered on the perforated groove of the insulating dielectric layer 5 can be any one of a quadrangular distribution, a herringbone distribution or a plum blossom distribution. The insulating dielectric layer 5 can be any one of silicon dioxide, silicon nitride, boron nitride, silicon oxynitride, aluminum oxide or rutile titanium dioxide. The preparation process of the insulating dielectric layer 5 can be any one of thermal oxidation growth, plasma enhanced chemical vapor deposition PECVD furnace growth, atomic layer deposition (ALD) or electron beam evaporation deposition of silicon oxide.

[0047] The preparation process of the heterogeneous metamaterial composite nanoribbon structure of the three-dimensional silicon nanoribbon 1 and the macroscopically assembled graphene nanoribbon 2 in the present invention is as follows: using a nanoribbon metal mask, using ICP (inductively coupled plasma dry etching system, using C4F8 and SF6 as reaction gases) to etch the macroscopically assembled graphene film, first preparing the patterned macroscopically assembled graphene nanoribbon 2. Using the nanoribbon metal mask, ICP etching is performed again to obtain the three-dimensional silicon nanoribbon 1. Under the condition of 200°C, chlorine gas is used to remove the surface nanoribbon metal mask, and finally a three-dimensional composite nanoribbon structure composed of a three-dimensional silicon strip nanostructure and macroscopically assembled graphene nanoribbons is obtained, such as Figure 1 and Figure 2 shown.

[0048] The structural unit graphics of the macro-assembled graphene nanoribbons 2 and the three-dimensional silicon nanoribbons 1 are designed as follows: a square nanoblock structure is connected between every two rectangular nanoribbons. In the present invention, a square nanostructure with a wider side length is connected between two rectangular nanoribbons with narrow sides, and the overall structure is axially symmetrical. The thickness of the structural unit of the macro-assembled graphene nanoribbons 2 is the thickness of the macro-assembled graphene film, and the thickness of the structural unit of the three-dimensional silicon nanoribbon 1 is determined according to actual needs to control the etching process, and the thickness range can be any one between 100-2000nm.

[0049] Due to the limited absorptivity of graphene to light (only 2.3% for a single layer), the temperature rise of the electronic system is limited, so the number of hot electrons distributed in the high-energy region is small, which is not enough to realize the collection and utilization of long-wavelength light far below the potential barrier, which greatly limits the utilization efficiency of the corresponding optoelectronic devices to long-wavelength light. Although due to the intrinsic photogenerated hot carrier effect of graphene, the energy of the high-energy electrons (hot tail) at the end of the thermal distribution of hot electrons is higher than that of the directly excited photogenerated electrons, the limited absorptivity of graphene leads to its low thermalization efficiency (limited hot electron temperature), which makes this "hot tail" have less carrier distribution in the high-energy region. The heterogeneous metamaterial composite of the three-dimensional silicon nanostrip 1 and the macroscopically assembled graphene nanostrip 2 in the present invention can realize the localization and enhancement of the light field on the one hand, and can also transfer energy to the electronic system through non-radiative relaxation methods such as Landau damping to directly excite the generation of hot carriers on the other hand. The results of both actions will improve the utilization of incident light energy and improve the efficiency of photoelectric conversion. When radiation photons are incident on the present invention, the macroscopically assembled graphene 3 has a unique multilayer structure and a three-dimensional nanocomposite structure design heterogeneously integrated with silicon. The macroscopically assembled graphene nanoribbon 2 and the three-dimensional silicon nanoribbon 1 will both absorb the photons cooperatively, and generate high-energy radiation electrons after absorbing high-energy photons. The generated photogenerated electron-hole pairs will be separated under the action of an external bias voltage and finally collected by the electrodes at both ends. The excited radiation electrons will travel between the layers of the macroscopically assembled graphene nanoribbon 2 and the three-dimensional silicon nanoribbon 1 and in the vertical transmission direction. The electrons that collide with the bound electrons continue to collide with other bound electrons; and because of the longer mean free path than other metal materials, the electrons move a longer path at the same energy, so that more photogenerated signals are collected, further reducing the minimum limit of radiation detection, and the collected light response can reflect the radiation energy of the incident particles; when an external bias is applied, the radiating electrons and the collided electrons will trigger the photoelectric effect when they reach the macroscopically assembled graphene / semiconductor interface, and the real-time reading of the radiation signal and intensity is achieved by reading the response current. And because the present invention itself can generate open-circuit voltage and short-circuit current through illumination without external power supply, illumination itself can make the device work, greatly reducing energy consumption, and the present invention can detect the infrared band at room temperature, without the need for additional liquid nitrogen refrigeration like traditional infrared detectors, which is a great breakthrough for infrared detectors.

[0050] The absorption spectrum of the present invention is compared with that of ordinary single-layer graphene or macroscopically assembled graphene. Figure 3 As shown, the absorption of the present invention in the hyperspectral band is enhanced beyond the existing silicon-based graphene photodetector. In addition, Figure 5The data of photocurrent and photoresponsivity test of the present invention and ordinary single-layer graphene silicon-based photodetectors in the ultraviolet, visible light and near-infrared bands are compared. It can be found that the present invention realizes high-performance detection of ultra-wide spectrum from deep ultraviolet to visible light to near-infrared band (300 nm-2100 nm) through the heterogeneous metamaterial composite of three-dimensional silicon nanoribbons 1 and the macroscopically assembled graphene nanoribbons 2, which greatly enhances the detection response of planar macroscopically assembled graphene silicon-based photodetectors in this band. By realizing the composite of macroscopically assembled graphene nanostructures and silicon nanostructures for the first time, the problem of weak detection performance of existing silicon-based graphene photodetectors in the ultra-wide spectral range, especially in the infrared band, is solved.

[0051] In order to further explore the potential application of the present invention in on-chip integrated devices, the device of the present invention is arrayed (8 × 8) as an example. The optical photograph of the array device is as follows: Figure 6 As shown, inspired by the high performance broadband photoresponse of photodetector arrays, the present invention demonstrates its application in real-time imaging. Figure 7 The left half of the information shows a schematic diagram of the setup of the real-time imaging method of the 8×8 photodetector array. The blue dot box shows the equivalent circuit of the imaging setup. 64 pixels are connected to a transimpedance amplifier (TIA) through a selector. The present invention uses control and sampling ports to select pixels. In addition, the current matrix is ​​transferred to a voltage through a transimpedance amplifier (TIA) and then acquired by a data acquisition (DAQ) system. Figure 7 As shown in the right half of the information, the present invention presents a real-time grayscale image of Chinese characters by drawing the photocurrent under illumination in the deep ultraviolet-visible light-near infrared band (375 nm, 532 nm, 1064 nm and 1550 nm).

[0052] In summary, the three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector and preparation method provided by the embodiment of the present invention can be integrated on-chip, realizing for the first time the composite of macroscopically assembled graphene nanostructures and silicon nanostructures, solving the problem of weak detection performance of existing silicon-based graphene photoelectric detectors in an ultra-wide spectral range, especially in the infrared band, and can work at room temperature without refrigeration, which is a huge breakthrough for infrared band detection. Secondly, it can also work without bias voltage, which is expected to bring extremely low energy consumption or even zero energy consumption, and has the advantage of low energy consumption.

[0053] Corresponding to the above-mentioned embodiment of a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector, the present invention also provides a method for preparing a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector. Figure 4 As shown, a preparation process of a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector includes the following steps:

[0054] (1) Preparation of silicon substrate: Take N-type lightly doped silicon wafer (thickness 100-500 um, resistivity 1-10 Ω·cm) as an example, cut it into the required size with a silicon wafer knife, clean the surface, put it into acetone, isopropanol, and deionized water solution for ultrasonic cleaning, and take it out and blow dry it with nitrogen;

[0055] (2) Patterning of the top electrode: Spin-coat the cleaned silicon wafer with photoresist so that the photoresist evenly covers the surface of the silicon wafer, pre-bake at 105°C for 5 min, and then use a photolithography machine to photolithography the silicon wafer after photolithography. After the photolithography is completed, mix the developer and water in a ratio of 1:7 to form a developing solution, and perform the developing operation. The metal deposition operation can be performed using thermal evaporation, electron beam evaporation or magnetron sputtering process, and then use acetone solution to lift-off the remaining metal except the electrode pattern, and then clean the acetone with isopropyl alcohol to obtain a complete electrode pattern.

[0056] (3-4) Patterning of silicon window: Continue to repeat the above-mentioned steps of photoresist coating-pre-baking-photolithography-development, and post-bake at 120℃ for 20 minutes to completely solidify the photoresist, which plays a role in protecting the oxide layer under the photoresist in the next wet etching. Then, the oxide layer of the window area not protected by the photoresist is etched in a buffered oxide etch (BOE) solution. The ratio of BOE solution is: NH4F: HF: H2O = 60 g: 30 ml: 100 ml. The etching rate of BOE solution with this ratio is 100 nm / min. When the thickness of the SiO2 layer in the silicon wafer used is 100 nm, etching for 1 minute is sufficient. After removing the device from the BOE solution, wash it in water, and then use acetone and isopropanol to remove the glue to complete the patterning of the silicon window.

[0057] (5) Transfer of macro-assembled graphene: A redox graphene film was prepared on a porous nano-alumina template (AAO) by filtration, and a macro-assembled graphene film was formed after high-temperature sintering at 2800°C. The transfer method of the macro-assembled graphene film is as follows: a drop of a mixture of ethanol and deionized water was dropped on the top electrode and the silicon window, and then a small piece of the macro-assembled graphene film was torn off with tweezers and evenly spread on the mixed liquid ball drop, and then the mixed liquid was blown away with argon gas, so that the macro-assembled graphene film area evenly covered the silicon window and the top electrode area, and was in close contact with them;

[0058] (6) Preparation of nano-strip metal mask: The silicon wafer after the above process is coated, and electron beam photoresist AR-P 669.04 is spin-coated at 600r / min for 10s and 6000r / min for 60s, and then baked in an oven at 150°C for 1h. Then, electron beam photoresist AR-P679.03 is spin-coated at 600r / min for 10s and 6000r / min for 60s, and then baked on a hot plate at 150°C for 3min. After exposure, an inverted trapezoidal structure is formed. Electron beam lithography is performed on the spin-coated thin film material. Metal is electron beam evaporated on the surface of the lithography pattern. The aluminum on the part with electron beam lithography is removed, and then ICP etching is performed. The nano-strip pattern is designed by high-resolution electron beam lithography, and metal is deposited by electron beam evaporation. The nano-strip metal mask is obtained by acetone stripping.

[0059] (7) Preparation of three-dimensional composite nanostructures: Using a nanostrip metal mask, ICP (inductively coupled plasma dry etching system, using C4F8 and SF6 as reaction gases) was used to etch the macro-assembled graphene film to prepare a patterned macro-assembled graphene nanostrip. Using the nanostrip metal mask, ICP etching was performed again to obtain a three-dimensional silicon strip nanostructure. Under the condition of 200°C, chlorine gas was used to remove the surface nanostrip metal mask, and finally a three-dimensional composite nanostructure consisting of a three-dimensional silicon strip nanostructure and macro-assembled graphene nanostrips was obtained.

[0060] (8) Preparation of bottom contact electrode: Taking gallium-indium alloy (Ga-In) as the bottom contact electrode as an example, the gallium-indium alloy is spot-coated on the back side of the silicon of the above-mentioned device to make ohmic contact between the bottom contact electrode and the top electrode.

[0061] The above embodiments provide an exemplary description of the present invention. Obviously, the specific implementation of the present invention is not limited to the above methods. As long as various improvements are made using the method concept and technical solution of the present invention, or they are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector, characterized in that: The wide spectrum detector includes: A silicon layer, on which an insulating dielectric layer is arranged, the insulating dielectric layer and the silicon layer have concentric grooves, a top electrode is arranged above the insulating dielectric layer, and a bottom contact electrode is arranged below the silicon layer; A three-dimensional silicon nanoribbon is arranged in a groove on a silicon layer and connected to the silicon layer; a macroscopically assembled graphene film is etched using an inductively coupled plasma dry etching system ICP using a nanoribbon metal mask, and firstly a patterned macroscopically assembled graphene nanoribbon is prepared; an ICP etching is performed again using a nanoribbon metal mask to obtain the three-dimensional silicon nanoribbon; at 200° C., chlorine is used to remove the surface nanoribbon metal mask, and finally a three-dimensional composite nanoribbon structure composed of a three-dimensional silicon strip nanostructure and macroscopically assembled graphene nanoribbons is obtained; the structural unit graphics of the macroscopically assembled graphene nanoribbon and the three-dimensional silicon nanoribbon are designed as follows: a square nanoblock structure is connected between every two rectangular nanoribbons, and the structure is generally axially symmetrical; The macroscopically assembled graphene is arranged above the top electrode and the insulating dielectric layer and is in direct contact with the layer, and is in contact with the three-dimensional silicon nanostrip to form a Schottky junction; the portion located in the groove area of ​​the insulating dielectric layer is patterned to form a macroscopically assembled graphene nanostrip; the macroscopically assembled graphene is a multilayer graphene nanofilm with consistent crystal stacking angles, or a macroscopically assembled graphene nanofilm doped with bromine, molybdenum chloride, copper chloride or molybdenum disulfide.

2. A three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector according to claim 1, characterized in that: The groove of the insulating dielectric layer is a perforated groove, and the top electrode is disposed above the insulating dielectric layer and arranged with the perforated groove of the insulating dielectric layer as the center.

3. A three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector according to claim 2, characterized in that: The perforated grooves of the insulating dielectric layer are polygonal grooves or circular grooves; the top electrode is distributed in a quadrangular distribution, a herringbone distribution or a plum blossom distribution with the perforated grooves of the insulating dielectric layer as the center; the insulating dielectric layer is any one of silicon dioxide, silicon nitride, boron nitride, silicon oxynitride, aluminum oxide or rutile titanium dioxide; the preparation process of the insulating dielectric layer is any one of thermal oxidation growth, plasma enhanced chemical vapor deposition PECVD furnace growth, atomic layer deposition ALD or electron beam evaporation deposition of silicon oxide.

4. The three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector according to claim 1, characterized in that: The three-dimensional silicon nanoribbon and the macroscopically assembled graphene nanoribbon are composited based on heterogeneous metamaterials to achieve high-performance detection of ultra-wide spectrum from deep ultraviolet to visible light to near infrared bands.

5. The three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector according to claim 1, characterized in that: When radiation photons enter the photodetector, the multilayer structure of the macroscopically assembled graphene and the composite structure design with the three-dimensional silicon nanostrips and the macroscopically assembled graphene nanostrips are utilized, and both nanostrips will cooperatively absorb the photons to excite radiation electrons. The generated photogenerated electron-hole pairs are separated under the action of an external bias voltage and are finally collected by the electrodes at both ends. The excited radiation electrons collide with bound electrons during the process of traveling between the layers of the macroscopically assembled graphene nanostrips and the three-dimensional silicon nanostrips and in the vertical transmission direction. The collided electrons continue to collide with other bound electrons, and the collected light response can reflect the radiation energy of the incident particles. When an external bias is applied, the radiated electrons and the impacted electrons trigger the photoelectric effect when they reach the macroscopically assembled graphene / semiconductor interface. By reading the response current, the radiation signal and intensity are read out in real time. Open-circuit voltage and short-circuit current are generated by light without the need for external power supply. The light itself enables the device to operate at room temperature and detect the infrared band.

6. The three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector according to claim 1, characterized in that: The macroscopic assembled graphene is prepared by mechanical exfoliation, suction sintering or chemical vapor deposition, and has a thickness of 30 to 60 nm.

7. The three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector according to claim 1, characterized in that: The material of the silicon layer and the three-dimensional silicon nanoribbon can be replaced by any one of germanium, indium gallium arsenide, gallium arsenide, cadmium telluride, indium phosphide, silicon carbide or gallium nitride.

8. The three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector according to claim 1, characterized in that: The bottom contact electrode is any one of gallium-indium alloy, metal silicide or metal aluminum, and is used for ohmic contact between the silicon layer and the top electrode; the material of the top electrode is any one of gold, aluminum, platinum, titanium-gold alloy, chromium-gold alloy or indium tin oxide; the deposition process of the top electrode is any one of thermal evaporation, electron beam evaporation or magnetron sputtering.

9. A method for preparing a three-dimensional silicon-based macroscopic graphene composite wide-spectrum detector, characterized in that: The method comprises the following steps: (1) Preparation of silicon substrate: Cut the silicon wafer into the required size, clean the surface, and ultrasonically clean it in acetone, isopropanol, and deionized water solution in sequence, then take it out and blow dry it with nitrogen; (2) Patterning of the top electrode: Spin-coat the cleaned silicon wafer with photoresist so that the photoresist evenly covers the surface of the silicon wafer, then perform pre-baking, photolithography and development operations, and metal deposition operations. Then use acetone to strip off the remaining metal except the electrode pattern, and then clean the acetone with isopropyl alcohol to obtain a complete electrode pattern; (3) Patterning of silicon windows: Repeat the steps of photoresist coating-pre-baking-photolithography-development in step (2) to completely solidify the photoresist and protect the oxide layer under the photoresist during wet etching; then, etch the oxide layer of the window area not protected by the photoresist in a buffered oxide etching BOE solution. After removing the device from the BOE solution, wash it in water, and then remove the photoresist with acetone and isopropyl alcohol to complete the patterning of the silicon window; (4) Transfer of macro-assembled graphene: A redox graphene film is prepared on a porous nano-alumina template AAO by a filtration method, and a macro-assembled graphene film is formed after sintering; the transfer method of the macro-assembled graphene film is as follows: a mixture of ethanol and deionized water is dripped onto the top electrode and the silicon window, and then a small piece of the macro-assembled graphene film is torn off and evenly spread on the mixed liquid ball drop, and then the mixed liquid is blown away with argon gas, so that the macro-assembled graphene film area evenly covers the silicon window and the top electrode area and is in close contact with them; (5) Preparation of nanostrip metal mask: Spread the silicon wafer, spin-coat the electron beam photoresist and dry it; after exposure, an inverted trapezoidal structure is formed; electron beam lithography is performed on the spin-coated thin film material; metal is evaporated on the surface of the lithography pattern by electron beam; aluminum on the part with electron beam lithography is removed, and then ICP etching is performed to lithography the designed nanostrip pattern, metal is deposited by electron beam evaporation, and acetone stripping is performed to obtain the nanostrip metal mask; (6) Preparation of three-dimensional composite nanostructures: Using a nanostrip metal mask, ICP is used to etch the macroscopically assembled graphene film to prepare a patterned macroscopically assembled graphene nanostrip; using the nanostrip metal mask, ICP etching is performed again to obtain a three-dimensional silicon strip nanostructure, and chlorine gas is used to remove the surface nanostrip metal mask to finally obtain a three-dimensional composite nanostructure consisting of a three-dimensional silicon strip nanostructure and macroscopically assembled graphene nanostrips; (7) Preparation of bottom contact electrode: A bottom contact electrode is fabricated on the back side of the silicon of the above device to establish ohmic contact between the bottom contact electrode and the top electrode.

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