阅读说明：本技术 一种新型二维同质结及其制备方法 (Novel two-dimensional homojunction and preparation method thereof ) 是由 侯鹏飞 蔡传洋 欧阳晓平 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种新型二维同质结,包括衬底、过渡层、绝缘层、二维功能层、左电极和右电极。本发明利用粒子束辐照技术在二维功能层上制备出具有不同半导体特性的不同区域,使得二维功能层成为二维同质结。所形成二维同质结性能稳定,避免了传统同质结中栅压调控的复杂结构,还避免了二维材料堆叠同质结的复杂制备,能够实现单层原子厚度的二维同质结,极大地减小器件尺寸,提高单位面积内器件单元的密度。另外,可以通过调控粒子束辐照技术中所采用的粒子种类,对二维同质结中二维功能层局部的半导体性质及性能进行调控,获得多种不同结构的二维同质结,可以用于光探测技术领域。(The invention discloses a novel two-dimensional homojunction, which comprises a substrate, a transition layer, an insulating layer, a two-dimensional functional layer, a left electrode and a right electrode. The invention utilizes the particle beam irradiation technology to prepare different areas with different semiconductor characteristics on the two-dimensional functional layer, so that the two-dimensional functional layer becomes a two-dimensional homojunction. The formed two-dimensional homojunction has stable performance, avoids a complex structure of grid voltage regulation and control in the traditional homojunction, also avoids complex preparation of two-dimensional material stacking homojunction, can realize the two-dimensional homojunction with single-layer atomic thickness, greatly reduces the size of a device, and improves the density of device units in unit area. In addition, the properties and performance of the local semiconductor of the two-dimensional functional layer in the two-dimensional homojunction can be regulated and controlled by regulating the types of particles adopted in the particle beam irradiation technology, so that the two-dimensional homojunction with various structures can be obtained, and the method can be used in the technical field of optical detection.)

1. A novel two-dimensional homojunction, comprising: the device comprises a substrate, a transition layer, an insulating layer, a two-dimensional functional layer, a left electrode and a right electrode;

wherein the transition layer is located on the substrate, and the insulating layer is located on the transition layer; the two-dimensional functional layer is located on the insulating layer, the left electrode is located on the left side of the two-dimensional functional layer, and the right electrode is located on the right side of the two-dimensional functional layer.

2. A novel two-dimensional homogeneous junction according to claim 1, wherein said substrate is a semiconductor material or an insulator material.

3. A novel two-dimensional homojunction according to claim 1 wherein said two-dimensional functional layers comprise an irradiated two-dimensional functional layer and an unirradiated two-dimensional functional layer;

the irradiated two-dimensional functional layer and the non-irradiated two-dimensional functional layer are arranged in parallel between the left electrode and the right electrode.

4. The novel two-dimensional homojunction of claim 1 wherein the two-dimensional functional layer is formed of In₂Se₃、Al₂S₃、Al₂Se₃、Al₂Te₃、Ga₂S₃、Ga₂Se₃、Ga₂Te₃、In₂S₃、In₂Te₃、MoS₂、WSe₂Or In doped with Co, Fe, Mn₂Se₃、Al₂S₃、Al₂Se₃、Al₂Te₃、Ga₂S₃、Ga₂Se₃、Ga₂Te₃、In₂S₃、In₂Te₃、MoS₂、WSe₂A single-layer or multi-layer two-dimensional ferroelectric or non-ferroelectric material.

5. A novel two-dimensional homojunction according to claim 4 wherein said two-dimensional functional layer has a thickness of 0.2-200 nm.

6. A novel two-dimensional homojunction according to claim 3 wherein said irradiated two-dimensional functional layer is obtained by irradiation with a particle beam.

7. A novel two-dimensional homojunction according to claim 6, wherein said particle beam irradiation is performed with He as the irradiation particle²⁺、Ar²⁺、C⁴⁺、O^2-、S^2-、Fe²⁺、、F^-、CF₃ ⁺、CF₂ ²⁺、CF³⁺One or a mixture of several of them.

The energy of the irradiation particles is 0.1 KeV-10 MeV, and the irradiation time of the particle beam is 0.01 s-600 s.

8. The novel two-dimensional homogeneous junction according to claim 3, wherein the left electrode and the right electrode are made of the same material or different materials;

the electrode material is composed of one or more of simple substances or alloys of gold, silver, platinum, copper, aluminum and tin, a carbon nano tube and graphene.

9. A method for preparing a novel two-dimensional homojunction according to any of claims 1 to 8, characterized in that. The method comprises the following steps:

(1) obtaining a two-dimensional material nanosheet serving as a two-dimensional functional layer by a micromechanical stripping method on a substrate attached with a transition layer and an insulating layer;

(2) covering the functional layer nanosheets with a mask or a copper mesh, and forming a left electrode and a right electrode at the left end and the right end of each functional layer nanosheet by using a small ion sputtering instrument to obtain a basic two-dimensional photodetector unit;

(3) covering the two-dimensional light detector unit by using a mask plate with a specially-made channel, exposing a region needing to be processed by a particle beam irradiation technology, and irradiating the two-dimensional light detector unit to form a two-dimensional homojunction.

10. The method of claim 3, wherein the distance between the left electrode and the right electrode in step (2) is 5nm-20000 nm.

Technical Field

The invention relates to the technical field of two-dimensional homojunction optical detection, in particular to a novel two-dimensional homojunction and a preparation method thereof.

Background

The optical detector can convert an optical signal which is difficult to directly quantify into an electrical signal which can be measured in strength and size, and is widely applied to the aspects of optical communication, optical imaging, environmental monitoring, remote monitoring and the like at present. The parameters of the wavelength range, the optical response value, the specific detection rate and the like which can be detected by the optical detector are important factors for determining the application range of the optical detector. The traditional optical detector generally selects a functional layer with a specific forbidden band width according to light in a specific wavelength range, but the optical detector has a single function and cannot adapt to the actual requirements of social production and life on the multifunctional optical detector.

To expand the functionality of the light detector, it is common to change the material of the functional layers and to modify the structure of the detector itself. The appearance of novel two-dimensional materials provides an important material basis for developing multifunctional novel photodetectors, so that the size of a novel photodetector unit is further reduced, and the number of units in a unit area is further increased. The novel optical detector based on the two-dimensional material can absorb light in an ultrathin planar structure in a large area, so that the novel optical detector has a high optical response value and a high specific detection rate. But still has the problems of narrow optical detection wavelength range and insufficient detection capability for weak light.

In order to further improve the performance of the novel optical detector, the two-dimensional heterojunction and the two-dimensional homojunction based on the two-dimensional material are applied to the two-dimensional material-based novel optical detector. One-dimensional or two-dimensional interfaces such as p-n, n-n, p-p and the like formed in the two-dimensional heterojunction and the two-dimensional homojunction can effectively separate electron hole pairs separated by weak light in the novel optical detector, improve the detection capability of the novel optical detector on the weak light, simultaneously expand the detection wavelength range of the novel optical detector and enable the light in the non-absorption wavelength range of the material to be detected. However, the two-dimensional heterojunction preparation process is complex, the yield is extremely low, the stacking of two-dimensional materials is generally performed by a two-dimensional material transfer platform, the in-plane orientation of the two-dimensional materials is difficult to control, and the number of layers of the two-dimensional materials is difficult to control when the two-dimensional heterojunction is prepared in a self-assembly mode, so that the homogenization is not facilitated, the two-dimensional heterojunction still stays in an experimental stage at present, and the industrial application is difficult to realize. Two-dimensional homojunctions generally have two implementations: one is the same as the two-dimensional heterojunction, the orientation of the two-dimensional material is difficult to control in the preparation stage, and the industrial application is difficult to realize when the two-dimensional material stays in the experimental stage; the other is a transistor structure regulated by an external field, compared with a two-dimensional heterojunction and the former two-dimensional homojunction, the structure has obvious advantages, but the performance of the two-dimensional material and the novel optical detector of the structure depends on the stability of the external field, and meanwhile, the external field regulation often increases the energy consumption of the device, so that the temperature of the device is easy to change, and the optical detection performance is unstable.

Therefore, how to form a novel two-dimensional homojunction, develop a novel method for realizing the same, and promote the application of the novel two-dimensional homojunction in the field of optical detection is a technical problem that needs to be solved urgently by technical personnel in the field.

Disclosure of Invention

In view of the above, the invention provides a novel two-dimensional homojunction and a preparation method thereof, wherein different regions with different semiconductor characteristics are prepared on a two-dimensional functional layer by a particle beam irradiation technology, so that the two-dimensional functional layer becomes the two-dimensional homojunction, the performance of the formed two-dimensional homojunction is stable, a complex structure of grid voltage regulation and control in the traditional homojunction is avoided, the complex preparation of two-dimensional material stacking homojunction is also avoided, the two-dimensional homojunction with single-layer atomic thickness can be realized, the size of a device is greatly reduced, and the density of device units in unit area is improved. In addition, the properties and performance of the local semiconductor of the two-dimensional functional layer in the two-dimensional homojunction can be regulated and controlled by regulating the types of particles adopted in the particle beam irradiation technology, so that the two-dimensional homojunction with various structures can be obtained, and the method can be used in the technical field of optical detection.

In order to achieve the purpose, the invention adopts the following technical scheme:

a novel two-dimensional homojunction, comprising: the device comprises a substrate, a transition layer, an insulating layer, a two-dimensional functional layer, a left electrode and a right electrode;

wherein the transition layer is located on the substrate, and the insulating layer is located on the transition layer; the two-dimensional functional layer is positioned on the insulating layer, the left electrode is positioned on the left side of the two-dimensional functional layer, and the right electrode is positioned on the right side of the two-dimensional functional layer

Further, the substrate is made of a semiconductor material or an insulator material, and the reflectivity of the insulating layer is not smaller than that of the contrast.

Preferably, the substrate is a composite material formed by one or more of intrinsic silicon, n-type silicon, p-type silicon, germanium single crystal, quartz, aluminum oxide, silicon oxide, mica, PET and hafnium oxide; the transition layer is a composite material formed by one or more of doped silicon, silicon oxide, germanium oxide, doped silicon oxide, modified mica, modified PET and doped hafnium oxide;

the insulating layer is a composite material formed by one or more of quartz, aluminum oxide, silicon oxide, mica, PET, hafnium oxide, doped hafnium oxide and the like;

the beneficial effect of adopting the further scheme is that: when the substrate is intrinsic silicon, n-type silicon, p-type silicon, germanium single crystal, quartz, aluminum oxide, silicon oxide or hafnium oxide, the substrate has good mechanical property and can bear the transition layer and the insulating layer; when the substrate is mica or PET, the material has good mechanical property, can bear a transition layer and an insulating layer, and can realize a flexible function; the transition layer can well connect the substrate and the insulating layer, the bonding property of the substrate and the insulating layer is improved, and meanwhile, the reflecting layer is added, so that the primary reflection of light transmitted into the insulating layer is increased, and the light absorption performance of the functional layer can be indirectly improved; the insulating layer can avoid the electric current between left electrode and the right electrode through substrate and transition layer, when avoiding increasing the device energy consumption, improves the device performance, and the reflectivity of insulating layer is not less than the functional layer can be guaranteed to pass through the light of functional layer transmission and reflect back the functional layer through the insulating layer, improves the absorption that the functional layer was set a camera to light, improves photoelectric conversion efficiency.

Further, the two-dimensional functional layer comprises an irradiated two-dimensional functional layer and an unirradiated two-dimensional functional layer;

the irradiated two-dimensional functional layer and the non-irradiated two-dimensional functional layer are the same two-dimensional material nanosheet;

the irradiated two-dimensional functional layer and the non-irradiated two-dimensional functional layer are arranged in parallel between the left electrode and the right electrode.

Further, the two-dimensional functional layer is composed of In₂Se₃、Al₂S₃、Al₂Se₃、Al₂Te₃、Ga₂S₃、Ga₂Se₃、Ga₂Te₃、In₂S₃、In₂Te₃、MoS₂、WSe₂Or In doped with Co, Fe, Mn₂Se₃、Al₂S₃、Al₂Se₃、Al₂Te₃、Ga₂S₃、Ga₂Se₃、Ga₂Te₃、In₂S₃、In₂Te₃、MoS₂、WSe₂One or more of the two-dimensional ferroelectric or non-ferroelectric materials of single layer or multilayer are obtained by a micromechanical lift-off process.

The beneficial effect of adopting the further scheme is that: the functional layer has higher carrier mobility, the forbidden band width is moderate, the functional layer still has good electrical property when being a single-layer two-dimensional material, the electrical property is stable at normal temperature, after a homojunction is formed, the functional layer is not easily influenced by the normal-temperature annealing effect, the stable property can be kept for a long time, in addition, the miniaturization can be realized, and the integration of microelectronic and photoelectronic processes is easy.

Preferably, the thickness of the functional layer is 0.2-200 nm, and the transverse dimension of the functional layer in one direction in a plane is larger than the thickness of the functional layer.

Further, the irradiated two-dimensional functional layer is obtained by a method of irradiation with a particle beam;

the irradiation particles in the particle beam irradiation are He²⁺、Ar²⁺、C⁴⁺、O^2-、S^2-、Fe²⁺、、F^-、CF₃ ⁺、CF₂ ²⁺、CF³⁺One or a mixture of several of them.

The energy of the irradiation particles is 0.1 KeV-10 MeV, and the irradiation time of the particle beam is 0.01 s-600 s.

Preferably, the area ratio of the irradiated two-dimensional functional layer to the non-irradiated two-dimensional functional layer is 1: 0.1-10, or the area ratio of different particle irradiation areas is 1: 0.1 to 10.

The beneficial effect of adopting the further scheme is that: the technical scheme can adjust the position, the length and the number of one-dimensional or two-dimensional interfaces of the homojunction formed in the functional layer by controlling the irradiation area in the particle beam irradiation technology; by regulating the types of particles in the particle beam irradiation technology, the concentration of local defects, the concentration of doping atoms and the like in the functional layer can be regulated, so that the semiconductor type and the electrical property of the local functional layer can be regulated; the depth of particles entering the functional layer can be regulated and controlled by controlling and controlling the energy of the particles in the particle beam irradiation technology, the proper particle energy can be selected for different thick functional layers, and the concentration of local defects and the concentration of doping atoms in the functional layer can be regulated and controlled by controlling the irradiation time when the energy particle irradiation is determined; the ratio of the areas of the irradiated parts to the areas of the non-irradiated parts and the ratio of the areas of the irradiated areas of different ions can be controlled to reduce the mutual influence of one-dimensional or two-dimensional interfaces of the homojunction, improve the separation efficiency of electrons and holes at the functional interface of the homojunction and further improve the optical detection performance of the two-dimensional homojunction.

Further, the left electrode and the right electrode are made of the same material or different materials;

preferably, the electrode material is composed of one or more of gold, silver, platinum, copper, aluminum and tin simple substance or alloy, carbon nanotube and graphene.

The beneficial effect of adopting the further scheme is that: the left electrode and the right electrode have good contact with the functional layer, and have certain particle irradiation resistance, so that the two-dimensional homojunction can be prevented from damaging the electrodes due to particle irradiation in the irradiation process.

The invention also provides a preparation method of the novel two-dimensional homojunction, which comprises the following steps:

(1) obtaining a two-dimensional material nanosheet serving as a two-dimensional functional layer by a micromechanical stripping method on a substrate attached with a transition layer and an insulating layer;

(2) covering the functional layer nanosheets with a mask or a copper mesh, and forming a left electrode and a right electrode at the left end and the right end of each functional layer nanosheet by using a small ion sputtering instrument to form a basic two-dimensional photodetector unit;

(3) covering the two-dimensional light detector unit by using a mask plate with a specially-made channel, exposing a region needing to be processed by a particle beam irradiation technology, and irradiating the two-dimensional light detector unit to form a two-dimensional homojunction.

Further, in the step (1), the substrate is made of a semiconductor material or an insulator material, and the reflectivity of the insulating layer attached to the substrate is greater than that of the contrast.

The beneficial effect of adopting the further scheme is that: and a part of incident light is reflected from the interface of the insulating layer and the functional layer and returns to the functional layer, so that the light absorption rate of the functional layer is improved.

Further, the thickness of the functional layer in the step (1) is 0.2-200 nm, and the transverse size of the functional layer in one direction in a plane is larger than the thickness of the functional layer.

The beneficial effect of adopting the further scheme is that: the plane conductivity of the functional layer can be ensured, and meanwhile, a stable two-dimensional homojunction interface is formed during particle beam irradiation.

Further, in the step (2), the distance between the left electrode and the right electrode is 5nm-20000nm, the distance between the left electrode and the right electrode is the width of a channel in the middle of the functional layer nanosheet, and the boundary connecting the electrode and the two-dimensional material is clear.

The beneficial effect of adopting the further scheme is that: the clear boundary of the connection of the electrode and the two-dimensional material is ensured, and the mask plate is favorably covered for carrying out the local irradiation of the functional layer.

Further, in step (3), a mask plate with a special channel is used to cover the two-dimensional photodetector unit, and the area to be processed by the particle beam irradiation technology is exposed.

The beneficial effect of adopting the further scheme is that: the region which does not need to be treated by the particle beam irradiation technique can be protected so that the particle beam irradiation technique acts only on a local region.

Further, mask plate holes are formed in the mask plate, and the irradiation particles irradiate the two-dimensional functional layer through the mask plate holes.

The invention has the beneficial effects that: the invention provides a novel two-dimensional homojunction and a preparation method thereof, wherein different regions with different semiconductor characteristics are prepared on a two-dimensional functional layer through a particle beam irradiation technology, so that the two-dimensional functional layer becomes the two-dimensional homojunction, the performance of the formed two-dimensional homojunction is stable, a complex structure of grid voltage regulation and control in the traditional homojunction is avoided, the complex preparation of two-dimensional material stacking homojunction is also avoided, the two-dimensional homojunction with single-layer atomic thickness can be realized, the size of a device is greatly reduced, and the density of device units in unit area is improved. In addition, the properties and performance of the local semiconductor of the two-dimensional functional layer in the two-dimensional homojunction can be regulated and controlled by regulating the types of particles adopted in the particle beam irradiation technology, so that the two-dimensional homojunctions with various structures can be obtained. When light irradiates on the two-dimensional material to generate a photon-generated carrier, the hole and the electron can be quickly separated and transmitted to two ends of the electrode by the built-in electric field of the homojunction, so that a larger photocurrent is generated, the photoresponse value and the specific detectivity in the photodetection process are improved, and the wavelength range of the detection light can be expanded.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a cross-sectional view of a two-dimensional photodetector cell of the present invention prior to fabrication into a novel two-dimensional homojunction;

FIG. 2 is a schematic radiation diagram and cross-sectional view of a mask placed on a two-dimensional photodetector unit prior to fabrication into a novel two-dimensional homojunction in accordance with the present invention;

FIG. 3 is a top view of a two-dimensional photodetector cell of the present invention prior to fabrication of a novel two-dimensional homojunction and a top view of the structure after fabrication of the novel two-dimensional homojunction;

FIG. 4 is a cross-sectional view of the novel two-dimensional homojunction of the present invention;

fig. 5 is a current-voltage curve diagram of the device unit under dark conditions and illumination of a 660nm laser when the two-dimensional photodetector unit is in a state before irradiation of the novel two-dimensional homojunction in embodiment 1 of the present invention, wherein the lowest current state is tested under dark conditions, and other laser beams with high current of 660nm wavelength are tested under the conditions that the optical power density is sequentially increased;

FIG. 6 shows that the fixed optical power density is 353.4mW/cm under 3V voltage bias when the two-dimensional photodetector unit is in a state before irradiation of the novel two-dimensional homojunction in embodiment 1 of the present invention²The cell responds to the current-time diagram of the light when the laser is switched on and off at intervals;

FIG. 7 is a graph of current-voltage curves of the new two-dimensional homojunction of example 1 formed after irradiation in the dark under illumination with 660nm laser, where the lowest current state is tested in the dark and the other high current curves are tested with laser beams with 660nm wavelength sequentially increasing the optical power density;

FIG. 8 shows that the fixed optical power density after irradiation of the novel two-dimensional homojunction of example 1 of the present invention is 353.4mW/cm under 3V voltage bias²The cell responds to the current-time diagram of the light when the laser is switched on and off at intervals;

in the drawings, the structures represented by the reference numerals are listed below: 1-substrate, 2-transition layer, 3-insulating layer, 4-functional layer, 41-non-irradiated two-dimensional functional layer, 42-irradiated two-dimensional functional layer, 5-left electrode, 6-right electrode, 7-mask plate and 8-mask plate hole.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The homogeneous junction in the embodiment of the invention is formed by forming two parts or a plurality of parts with different semiconductor properties and electric transport properties in the same nanosheet functional layer after the particle beam irradiation technology is used. When the particle beam irradiation technology acts on the functional layer, different particles can interact with atoms in the functional layer differently, so that different physical and chemical reactions occur, and changes such as vacancy, intercalation atoms, atom replacement and the like can be formed in the functional layer. By controlling the energy and the action time of the particle beam, the vacancy, the intercalation atom and the atom replacement formed in the functional layer can be finely controlled. The method can regulate and control a plurality of different homogeneous structures such as p-n, n-n, p-p, p-n-p-n, n-p-n and the like in the same functional layer.

Examples

A novel two-dimensional homojunction, comprising: the device comprises a substrate 1, a transition layer 2, an insulating layer 3, a two-dimensional functional layer 4, a left electrode 5 and a right electrode 6;

wherein, the transition layer 2 is positioned on the substrate 1, and the insulating layer 3 is positioned on the transition layer 2; the two-dimensional functional layer 4 is arranged on the insulating layer 3, the left electrode 5 is arranged on the left side of the two-dimensional functional layer 4, and the right electrode 6 is arranged on the right side of the two-dimensional functional layer 4

Further, the two-dimensional functional layer 4 includes the two-dimensional functional layer 42 that is irradiated and the two-dimensional functional layer 41 that is not irradiated;

the irradiated two-dimensional functional layer 42 and the non-irradiated two-dimensional functional layer 41 are the same two-dimensional material nanosheet;

the irradiated two-dimensional functional layer 42 and the non-irradiated two-dimensional functional layer 41 are arranged in parallel between the left electrode and the right electrode.

Example 1

In this embodiment, the substrate is n-type silicon and the transition layer is amorphous SiO_xInsulating layer SiO₂The functional layer is alpha-In with a thickness of 50nm₂Se₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, the local part of the functional layer is irradiated by particle beams, and the irradiated particles are Ar²⁺Dose of radiation is about 3.5X 10¹³cm^-2. The method comprises the following steps:

(1) SiO 2nm in the transition layer by micro-mechanical stripping method_xAnd SiO with an insulating layer of 300nm₂Preparing a coated n-type silicon substrate to obtain alpha-In with the length of 70um, the width of 30um and the thickness of 50nm₂Se₃A two-dimensional material nanosheet sample, wherein the two-dimensional material nanosheet is used as a two-dimensional functional layer;

(2) covering a functional layer by using a copper mask plate with a diameter of 20 mu m and a fine line interval, wherein the functional layer can be seen on two sides of the fine line, after the copper mask plate is fixed, depositing gold electrodes on two sides of the fine line by using a small-sized ion sputtering instrument, wherein the air pressure in the small-sized ion sputtering instrument is 6Pa, the current is 4-6 mu A, the deposition time is 240s in the deposition process, and preparing a compact gold electrode to prepare a two-dimensional photodetector unit;

(3) after the two-dimensional photodetector unit is prepared, removing the copper mask plate, placing a steel mask plate with a rectangular space of 10 micrometers multiplied by 50 micrometers on the two-dimensional photodetector unit, exposing a part to be irradiated in a functional layer of the two-dimensional photodetector unit, fixing the mask plate, placing the mask plate in a particle beam irradiation cavity, and setting the type of particle irradiation as Ar²⁺At a fluence of 3.5X 10¹³cm^-2And stopping irradiation, taking out the cavity, and removing the steel mask plate to form a two-dimensional homojunction unit.

Before the preparation of the homojunction in the embodiment 1 is completed, a laser with a wavelength of 660nm is adopted to test a two-dimensional photodetector unit, and the current of the photodetector in a dark state is tested firstly; when the environment of the photoelectric detector is converted into light, the functional layer alpha-In₂Se₃Can generate a plurality of photo-generated electrons, and the same voltage applied between the left and right electrodes can generate higher current; likewise, increasing the optical power of the laser can produce a greater current. The test structure is shown in fig. 3. When using the injection of 3.5 multiplied by 10¹³cm^-2Ar of (2)²⁺After the particle beam irradiation, the two-dimensional photodetector unit is converted into a homojunction, and the voltage-current curve is tested using the same parameters. The result shows that the formed homojunction is greatly improved in light detection performance, and the curve shows great asymmetry under positive and negative voltages. Through calculation, the optical power density is 0.17mw/cm²When the voltage is positive, the photoelectric current, the responsivity, the external quantum efficiency and the detectivity are improved by 378%, 378% and 251%; the photocurrent, responsivity, external quantum efficiency and detectivity of negative voltage are improved by 113%, 113% and 105%.

When the environment of the light detector is changed from bright to dark, no laser is emitted into the functional layer alpha-In₂Se₃Resulting in no new photo-generated electrons being generated and a sudden drop in current. However, the current in the photodetector does not disappear immediately, but shows a gradually decreasing trend, and the response speed results of the two-dimensional photodetector unit test before irradiation are shown in fig. 4. When a voltage of 3V is applied between the left electrode and the right electrode, the light/dark condition of the two-dimensional light detector unit is changed, and the two-dimensional light detector unit is switched back and forth in the same period, wherein the on-state response time is 76ms, and the off-state response time is 112 ms. The injection amount is 3.5 × 10¹³cm^-2Ar of (2)²⁺After the particle beam irradiation, the two-dimensional light detector unit is converted into a homojunction, and the on-state response time is 40ms, and the off-state response time is 52 ms.

The following examples were conducted in the same manner as example 1 except that the contents were changed from those of example 1.

Example 2

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm SiO₂The functional layer is alpha-In with the thickness of 50nm₂Se₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 3.5X 10¹³cm^-2。

Example 3

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm SiO₂The functional layer is alpha-In with the thickness of 100nm₂Se₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 3.5X 10¹³cm^-2。

Example 4

The substrate is a PET substrate, the transition layer is PET, the insulating layer is PET, and the functional layer is alpha-In with the thickness of 50nm₂Se₃The nano-sheet, the left electrode and the right electrode are silver electrodes, and the irradiation particles of particle beams are Ar²⁺The irradiation fluence is 7X 10¹³cm^-2。

Example 5

The substrate is a quartz substrate, the transition layer is quartz, the insulating layer is quartz, and the functional layer is alpha-In with a thickness of 50nm₂Se₃The nano-sheet, the left electrode and the right electrode are all copper electrodes, and the irradiation particles of particle beams are Ar²⁺The irradiation fluence is 7X 10¹³cm^-2。

Example 6

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm SiO₂The functional layer is alpha-In with the thickness of 50nm₂Se₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 14X 10¹³cm^-2。

Example 7

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm SiO₂And the functional layer is 50nm thick Al₂S₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 3.5X 10¹³cm^-2。

Example 8

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm SiO₂"Gong" exerciseEnergy layer of 100nm thick Al₂S₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 3.5X 10¹³cm^-2。

Example 9

The substrate is a PET substrate, the transition layer is PET, the insulating layer is PET, and the functional layer is Al with the thickness of 50nm₂Se₃The nano-sheet, the left electrode and the right electrode are silver electrodes, and the irradiation particles of particle beams are Ar²⁺The irradiation fluence is 7X 10¹³cm^-2。

Example 10

The substrate is a PET substrate, the transition layer is PET, the insulating layer is PET, and the functional layer is Ga 50nm thick₂S₃The nano-sheet, the left electrode and the right electrode are silver electrodes, and the irradiation particles of particle beams are Ar²⁺The irradiation fluence is 14X 10¹³cm^-2。

Example 11

The substrate is alumina, the transition layer is alumina, the insulating layer is alumina, and the functional layer is Ga 50nm thick₂S₃The nano-sheet, the left electrode and the right electrode are silver electrodes, and the irradiation particles of particle beams are Ar²⁺The irradiation fluence is 3.5X 10¹³cm^-2。

Example 12

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm SiO₂Ga having a thickness of 100nm as a functional layer₂Te₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 3.5X 10¹³cm^-2。

Example 13

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm HfO₂And the functional layer is In with a thickness of 10nm₂S₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 2.1X 10¹³cm^-2。

Example 14

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm HfO₂And the functional layer is In with a thickness of 10nm₂Te₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 2.1X 10¹³cm^-2。

Example 15

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm HfO₂Co-doped alpha-In with a functional layer thickness of 10nm₂Se₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 2.1X 10¹³cm^-2。

Example 16

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm HfO₂The functional layer is Fe-doped alpha-In with the thickness of 10nm₂Se₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and the irradiation particle of the particle beam is Ar²⁺The irradiation fluence is 2.1X 10¹³cm^-2。

Example 17

The substrate is n-type silicon, and the transition layer is SiO 2nm_xInsulating layer of 50nm HfO₂The functional layer is Fe-doped alpha-In with the thickness of 10nm₂Se₃The nano-sheet, the left electrode and the right electrode are all gold electrodes, and particle beam irradiation particles adopted by a half functional layer close to the left electrode are Ar²⁺The irradiation fluence is 2.1X 10¹³cm^-2The half functional layer close to the right electrode adopts particle beam irradiation particles C⁴⁺The irradiation fluence is 3X 10¹³cm^-2。

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.