WO2021077838A1

WO2021077838A1 - Photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction, and preparation method therefor

Info

Publication number: WO2021077838A1
Application number: PCT/CN2020/105551
Authority: WO
Inventors: 张晗; 王慧德; 郭志男
Original assignee: 深圳大学
Priority date: 2019-10-25
Filing date: 2020-07-29
Publication date: 2021-04-29
Also published as: CN111048619A

Abstract

A photodetector based on a black phosphorus/graphene/molybdenum disulfide heterojunction, comprising a substrate (10), a first electrode (20), a second electrode (30), a black phosphorus thin film layer (40), a graphene (50), and a molybdenum disulfide layer layer (60). The first electrode (20) and the second electrode (30) are arranged at an interval on a surface on one side of the substrate (10), the first electrode (20) and the second electrode (30) forming a channel structure. The black phosphorus thin film layer (40), the graphene layer (50), the and molybdenum disulfide layer (60) are sequentially stacked in the channel structure, the first electrode (20) and the second electrode (30) contacting the black phosphorus thin film layer (40) and the molybdenum disulfide layer (60) respectively. The photodetector features little dark current and good responsiveness, and can make possible highly flexible broadband photodetection, aiding broad application thereof. A method for preparing the photodetector based on a black phosphorus/graphene/molybdenum disulfide heterojunction, the method being simple and easy to operate.

Description

Photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction and preparation method thereof

The present invention claims the priority of the prior application of the application number 201911026271.3 filed on October 25, 2019 under the title of "Black Phosphorus/Graphene/Molybdenum Disulfide Heterojunction-Based Photodetector and Its Preparation Method". The content of the first application is incorporated into this text by way of introduction.

Technical field

The invention relates to the field of photodetectors, in particular to a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction and a preparation method thereof.

Background technique

A photodetector is a device that converts optical signals into electrical signals. Photoelectric detectors have a wide range of uses, covering various fields of military and national economy. For example, they are mainly used for ray measurement and detection, industrial automatic control, photometric measurement, etc. in the visible and near-infrared bands.

Traditional photodetectors based on semiconductor materials such as silicon, gallium arsenide, and indium gallium arsenide generally have problems such as narrow response bands and insufficient response sensitivity. Commercial infrared band detectors must work normally at ultra-low temperatures, which makes the cost of the detectors sharply increased and is not easy to integrate. At present, high-efficiency photodetectors formed by using new two-dimensional material semiconductors in scientific research and industrial production are developing rapidly. For example, a P-N junction photodetector based on black phosphorus/molybdenum disulfide van der Waals heterojunction can achieve a detection range covering visible light to mid-infrared light and a fast response speed. However, the current reported P-N junction has the problem of excessive dark current, which makes the sensitivity of the detector low, which greatly restricts its application in related fields.

Therefore, further development of photodetectors with low dark current, fast response and high sensitivity is of great significance to its development.

Summary of the invention

In order to solve the above problems, the present invention provides a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction, which is solved by setting the black phosphorus/graphene/molybdenum disulfide heterojunction in the photodetector. The problem of excessive dark current during the use of the existing photodetector realizes low dark current, fast response, high sensitivity, and wide-band photodetection, and the photodetector can efficiently detect visible light and infrared light at the same time, which is beneficial to its wide range application.

In the first aspect, the present invention provides a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction, including a substrate, a first electrode, a second electrode, a black phosphorus film layer, a graphene layer, and a disulfide A molybdenum layer, the first electrode and the second electrode are arranged on one side surface of the substrate at intervals, a channel structure is formed between the first electrode and the second electrode, the black phosphorous film layer, The graphene layer and the molybdenum disulfide layer are sequentially stacked and arranged in the channel structure, and the first electrode and the second electrode are in contact with the black phosphorous film layer and the molybdenum disulfide layer, respectively connection.

In the present invention, a black phosphorus/graphene/molybdenum disulfide heterojunction is set in the photodetector. Among them, the band gap of black phosphorus and graphene is very narrow, and the light response to infrared band is obvious, and the band of molybdenum disulfide The gap is suitable for the detection of visible light, so the heterojunction formed by the combination of the three can take advantage of the synergy of the three, so that the photodetector has the ability to efficiently detect visible light and infrared light at room temperature, and realizes wide-band light detection; at the same time, Compared with the black phosphorus/molybdenum disulfide PN junction heterojunction photodetector in the prior art, the black phosphorus/graphene/molybdenum disulfide heterojunction provided by the present invention is the first in the black phosphorus/molybdenum disulfide PN junction The graphene layer is added to the junction, which widens the space charge region of the heterojunction and reduces the reverse cut-off current of the heterojunction device under no light conditions, that is, effectively reduces the dark current and improves the photoelectric response sensitivity. At the same time, the excellent broad-spectrum photodetection performance of graphene can play a great role under the built-in electric field of the heterojunction. This is due to the photogenerated electron-hole pairs generated by the graphene under the built-in electric field of the heterojunction. , Can separate quickly and effectively, which will effectively improve the photoelectric responsivity of the entire detector, and at the same time broaden the detection range of the detector to the terahertz band. Furthermore, the small dark current and the large photoelectric responsivity will jointly lead to the ultra-high detection rate of the detector. Theoretically, it can reach ^{more than 10 12} Jone in the infrared band, which can reach the detection rate of commercial infrared detectors.

In the present invention, the substrate may be a flexible substrate or a rigid substrate. Optionally, the material of the substrate includes at least one of polyethylene terephthalate, polyethylene naphthalate, and polydimethylsiloxane. In this case, the substrate is a flexible substrate. To improve the flexibility of the photodetector, it can be stretched and bent to further broaden the application range of the photodetector, and it can be used in but not limited to the field of flexible electronics. Specifically, but not limited to, the substrate may be a silicon substrate, a silicon dioxide substrate, or a polyethylene terephthalate substrate. In the present invention, the size of the substrate is not limited, and the specific size can be selected according to actual needs.

In the present invention, the detection range of the detector is from the ultraviolet band to the terahertz band.

In the present invention, the detection range of the detector is greater than 10 ¹² Jone. Further, the detection range of the detector is greater than 10 ¹⁴ Jone. Furthermore, the detection range of the detector is greater than 10 ¹⁶ Jone, which is 4 orders of magnitude higher than that of a commercial infrared detector.

Optionally, the material of the first electrode and the second electrode includes at least one of gold, silver, platinum, copper, chromium, and titanium. In the present invention, the materials of the first electrode and the second electrode may be the same or different, which is not limited.

Further, the first electrode and the second electrode include a connection layer and a metal layer, and the connection layer is in contact with the substrate. Furthermore, the material of the connection layer includes chromium and/or titanium, and the material of the metal layer includes at least one of gold, silver, platinum and copper. In the present invention, in addition to being used for conducting electricity, the connecting layer also has a certain connection function, so that the metal layer and the substrate are better adhered and connected, and the bonding force between the first electrode and the second electrode and the substrate is improved. Specifically, but not limited to, the first electrode and the second electrode are both formed by stacking a chromium layer and a gold layer, the chromium layer is in contact with the substrate, and the thickness of the chromium layer is 5 nm-10 nm, The thickness of the gold layer is 20 nm-80 nm.

Optionally, the thickness of the first electrode is 25nm-90nm, and the thickness of the second electrode is 25nm-90nm.

Optionally, the distance between the first electrode and the second electrode is 1 μm-15 μm. That is, the size of the channel structure formed between the first electrode and the second electrode in the first direction is 1 μm-15 μm.

In the present invention, the black phosphorus film layer is composed of a single layer of black phosphorus or multiple layers of black phosphorus, the graphene layer is composed of a single layer of graphene or multiple layers of graphene, and the molybdenum disulfide layer is composed of a single layer of graphene. Layered molybdenum disulfide composition or multilayer molybdenum disulfide composition. Specifically, but not limited to, the single-layer molybdenum disulfide has a direct band gap with a size of about 1.9eV, and the multilayer molybdenum disulfide has an indirect band gap with a size of about 1.2eV, and the single-layer black phosphorus (with a size of about 2eV) ) To multilayer black phosphorus (about 0.3eV) are all direct band gaps.

Optionally, the thickness of the black phosphorous film layer is 0.5 nm-50 nm, the thickness of the graphene layer is 0.3 nm-15 nm, and the thickness of the molybdenum disulfide layer is 0.6 nm-50 nm.

Optionally, part of the black phosphorous film layer is disposed on the surface of the first electrode, or the black phosphorous film layer is disposed in the channel structure and is close to the first electrode at one end of the second electrode Contact connection. That is, when part of the black phosphorous film layer is disposed on the surface of the first electrode, the part of the black phosphorous film layer is directly disposed on the surface of the first electrode, that is, when it is perpendicular to the surface of the substrate. In the direction, the two are stacked and connected, or when the black phosphorous film layer is arranged in the channel structure and is in contact with the end of the first electrode close to the second electrode, that is, in parallel to the In the direction of the surface of the substrate, the first electrode and the black phosphorous film layer are arranged in sequence and connected in contact.

Optionally, part of the molybdenum disulfide layer is disposed on the surface of the second electrode, or the molybdenum disulfide layer is disposed in the channel structure and is close to the second electrode at one end of the first electrode Contact connection. That is to say, when part of the molybdenum disulfide layer is disposed on the surface of the second electrode, the part of the molybdenum disulfide layer is directly disposed on the surface of the second electrode, that is, when it is perpendicular to the surface of the substrate. In the direction, the two are stacked and connected, or when the molybdenum disulfide layer is arranged in the channel structure and is in contact with the end of the second electrode close to the first electrode, that is, in parallel to the In the direction of the surface of the substrate, the second electrode and the molybdenum disulfide layer are sequentially arranged and connected in contact.

Further, part of the black phosphorous film layer is disposed on the surface of the first electrode, and part of the molybdenum disulfide layer is disposed on the surface of the second electrode.

Optionally, the overlap area of the orthographic projection of the black phosphorous film layer on the substrate and the orthographic projection of the molybdenum disulfide layer on the substrate is the same as the orthographic projection of the graphene layer on the substrate. The projection area ratio is 1: (0.2-5). At this time, the black phosphorus/graphene/molybdenum disulfide heterojunction can be better used to improve the dark current of the photodetector.

Optionally, the overlap area of the orthographic projection of the black phosphorous film layer on the substrate and the orthographic projection of the molybdenum disulfide layer on the substrate is the same as the orthographic projection of the graphene layer on the substrate. The projections are completely overlapped, which is beneficial to reduce the dark current of the photodetector and improve the fast response.

In the present invention, the black phosphorous film layer, the graphene layer and the molybdenum disulfide layer are connected by van der Waals force to form a van der Waals force heterojunction, so that the overall structure of the photodetector is stable.

Optionally, the photodetector further includes a self-healing electrode, and the self-healing electrode is arranged on the surface of the first electrode and/or the second electrode.

In the present invention, the photodetector further includes a self-healing electrode, and the self-healing electrode is arranged on the surface of the first electrode and/or the second electrode, and is used in the first electrode and/or the surface of the second electrode. When small cracks and cracks appear on the second electrode, the small cracks and cracks can be repaired to prevent the cracks and cracks from affecting the work of the photodetector, thereby realizing a self-repairing process and increasing the service life of the photodetector.

Further, the self-healing electrode includes an electrode base and a self-healing layer, and the self-healing layer is disposed on a side surface of the electrode base close to the first electrode and/or the second electrode.

Furthermore, the material of the self-healing layer includes polyurethane, epoxy resin, ethylene-vinyl acetate copolymer, polyimide, polycaprolactone, polylactic acid, polyglycolic acid, polylactic acid-glycolic acid copolymer , At least one of polyvinyl alcohol and its derivatives.

The photodetector based on the black phosphorus/graphene/molybdenum disulfide heterojunction provided by the present invention can efficiently detect visible light and infrared light at the same time, can realize low dark current, fast response photoelectric detection, high sensitivity, wide detection band, and widening Its scope of application.

In the second aspect, the present invention provides a method for preparing a photodetector based on a black phosphorus/graphene/molybdenum disulfide heterojunction, including:

Providing a substrate, depositing electrode material on one side surface of the substrate to form a first electrode and a second electrode arranged at intervals, wherein a channel structure is formed between the first electrode and the second electrode;

A black phosphorus film, a graphene film, and a molybdenum disulfide film are sequentially stacked and arranged in the channel structure, and the first electrode and the second electrode are in contact with the black phosphorus film and the molybdenum disulfide film, respectively Connected to obtain a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction.

In the present invention, the black phosphorous film, the graphene film, and the molybdenum disulfide film may be prepared by, but not limited to, the stripping method.

Optionally, the preparation method further includes:

Coating a self-healing material on the surface of the first electrode and/or the second electrode to form a self-healing layer;

An electrode material is deposited on the self-healing layer to form a self-healing electrode.

The preparation method of the photodetector based on the black phosphorus/graphene/molybdenum disulfide heterojunction provided by the invention is simple and easy to operate, and can produce a photodetector with low dark current and fast response.

The beneficial effects of the present invention:

The present invention provides a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction. By setting the black phosphorus/graphene/molybdenum disulfide heterojunction in the photodetector, the existing photodetector is solved The problem of excessive dark current realizes low dark current, fast response, high sensitivity, wide-band photoelectric detection, and the photodetector can efficiently detect visible light and infrared light at the same time, which is conducive to its wide application. The invention also provides a method for preparing a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction. The method is simple and easy to operate, and can produce a photodetector with low dark current and fast response.

Description of the drawings

FIG. 1 is a schematic structural diagram of a photodetector based on a black phosphorus/graphene/molybdenum disulfide heterojunction according to an embodiment of the present invention.

2 is a schematic structural diagram of a photodetector based on a black phosphorus/graphene/molybdenum disulfide heterojunction according to another embodiment of the present invention.

3 is a flow chart of a method for manufacturing a photodetector based on a black phosphorus/graphene/molybdenum disulfide heterojunction according to an embodiment of the present invention.

Fig. 4 is a test result diagram of a photodetector based on a black phosphorous/graphene/molybdenum disulfide heterojunction provided in Example 1 of the present invention. In Fig. 4 (a) is an IV curve diagram under a non-light condition, and Fig. 4 The middle (b) is the It curve when there is no light and there is light alternately.

Figure 5 is a graph of the test results of a black phosphorous/molybdenum disulfide-based photodetector provided by the comparative example of the present invention. Figure 5 (a) is an IV curve diagram under non-light conditions, and Figure 5 (b) is a graph showing the results of a photodetector based on black phosphorous/molybdenum disulfide. It graph when light and light alternately appear.

Detailed ways

The following are the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also considered This is the protection scope of the present invention.

Please refer to FIG. 1, for an embodiment of the present invention, a photodetector based on a black phosphorous/graphene/molybdenum disulfide heterojunction is provided, which includes a substrate 10, a first electrode 20, a second electrode 30, and a black phosphorous film The layer 40, the graphene layer 50 and the molybdenum disulfide layer 60, the first electrode 20 and the second electrode 30 are arranged on one side surface of the substrate 10 at intervals, and a channel structure is formed between the first electrode 20 and the second electrode 30, black The phosphorous film layer 40, the graphene layer 50 and the molybdenum disulfide layer 60 are sequentially stacked and arranged in the channel structure, and the first electrode 20 and the second electrode 30 are in contact and connected with the black phosphorous film layer 40 and the molybdenum disulfide layer 60, respectively.

In the present invention, by setting the black phosphorus/graphene/molybdenum disulfide heterojunction in the photodetector, the photodetector has the ability to efficiently detect visible light and infrared light at room temperature, and at the same time has very low darkness. The current leads to high photoelectric response sensitivity of the photodetector.

In the present invention, the substrate 10 may be a flexible substrate or a rigid substrate. In one embodiment of the present invention, the material of the substrate 10 includes at least one of polyethylene terephthalate, polyethylene naphthalate, and polydimethylsiloxane. In this case, the substrate 10 It is a flexible substrate to improve the flexibility of the photodetector and further broaden the application range of the photodetector. It can be used but not limited to the field of flexible electronics. Specifically, the substrate 10 may be, but not limited to, a silicon substrate, a silicon dioxide substrate, or a polyethylene terephthalate substrate. In the present invention, the size of the substrate 10 is not limited, and the specific size can be selected according to actual needs. Optionally, the thickness of the substrate 10 is 100 μm-1000 μm. Further, the thickness of the substrate 10 is 300 μm-800 μm.

In an embodiment of the present invention, the material of the first electrode 20 and the second electrode 30 includes at least one of gold, silver, platinum, copper, chromium and titanium. In the present invention, the materials of the first electrode 20 and the second electrode 30 may be the same or different, which is not limited. Further, the first electrode 20 and the second electrode 30 include a connection layer and a metal layer, and the connection layer is in contact with the substrate 10. Furthermore, the material of the connection layer includes chromium and/or titanium, and the material of the metal layer includes at least one of gold, silver, platinum and copper. In the present invention, in addition to being used for conducting electricity, the connection layer also plays a role in connection, so that the metal layer and the substrate 10 are better adhered and connected, and the bonding force between the first electrode 20 and the second electrode 30 and the substrate 10 is improved. . Optionally, the thickness of the connection layer is 5 nm-10 nm, and the thickness of the metal layer is 20 nm-80 nm. Further, the thickness of the connection layer is 7nm-9nm, and the thickness of the metal layer is 23nm-71nm. In a specific embodiment of the present invention, both the first electrode 20 and the second electrode 30 are formed by stacking a chromium layer and a gold layer, the chromium layer is in contact with the substrate 10, the thickness of the chromium layer is 5nm-10nm, and the thickness of the gold layer is 20nm -80nm.

In one embodiment of the present invention, the thickness of the first electrode 20 is 25 nm-90 nm, and the thickness of the second electrode 30 is 25 nm-90 nm. Further, the thickness of the first electrode 20 is 30 nm-80 nm, and the thickness of the second electrode 30 is 30 nm-80 nm.

In an embodiment of the present invention, the distance between the first electrode 20 and the second electrode 30 is 1 μm-15 μm. That is, the size of the channel structure formed between the first electrode 20 and the second electrode 30 in the first direction is 1 μm-15 μm.

In the present invention, the first electrode 20 and the second electrode 30 are respectively in contact with the black phosphorous film layer 40 and the molybdenum disulfide layer 60, so the first electrode can be used as a drain and the second electrode can be used as a source.

In the present invention, the black phosphorus film layer 40 is composed of a single layer of black phosphorus or multiple layers of black phosphorus, the graphene layer 50 is composed of a single layer of graphene or multiple layers of graphene, and the molybdenum disulfide layer 60 is composed of a single layer of disulfide. Molybdenum composition or multi-layer molybdenum disulfide composition. Specifically, but not limited to, the single-layer molybdenum disulfide has a direct band gap with a size of about 1.9eV, and the multilayer molybdenum disulfide has an indirect band gap with a size of about 1.2eV, and the single-layer black phosphorus (with a size of about 2eV) ) To multilayer black phosphorus (about 0.3eV) are all direct band gaps. The energy band gap of the black phosphorus/graphene/molybdenum disulfide heterojunction determines the photon energy required to excite the electronic transition, the range of response photon frequencies, and the applicable spectral range, so that the response spectral range of the photodetector can be adjusted. Conducive to broaden its application scenarios.

In one embodiment of the present invention, the thickness of the black phosphorous film layer 40 is 0.5nm-50nm, the thickness of the graphene layer 50 is 0.3nm-15nm, and the thickness of the molybdenum disulfide layer 60 is 0.6nm-50nm, adjusting the photodetector The response spectrum range, and is conducive to achieve low dark current effect. Further, the thickness of the black phosphorous film layer 40 is 0.5 nm-40 nm, the thickness of the graphene layer 50 is 0.3 nm-10 nm, and the thickness of the molybdenum disulfide layer 60 is 0.6 nm-40 nm, which is beneficial to further reducing the dark current.

In the present invention, the black phosphorous film layer 40, the graphene layer 50 and the molybdenum disulfide layer 60 are sequentially stacked and arranged in the channel structure, and the first electrode 20 and the second electrode 30 are respectively connected with the black phosphorous film layer 40 and the molybdenum disulfide layer. Layer 60 is connected in contact. In a specific embodiment of the present invention, the first electrode 20 is in contact and connection with the black phosphorous film layer 40, and is not in direct contact and connection with the graphene layer 50 and the molybdenum disulfide layer 60, and the second electrode 30 is in contact and connection with the molybdenum disulfide layer 60 , It is not in direct contact with the black phosphor film layer 40 and the graphene layer 50 to achieve simultaneous efficient detection of visible light and infrared light, reduce dark current, and achieve fast-response photoelectric detection.

In an embodiment of the present invention, part of the black phosphorous film layer 40 is disposed on the surface of the first electrode 20, or the black phosphorous film layer 40 is disposed in the channel structure and is in contact with the end of the first electrode 20 close to the second electrode 30. That is, when part of the black phosphorous film layer 40 is disposed on the surface of the first electrode 20, the part of the black phosphorous film layer 40 is directly disposed on the surface of the first electrode 20, that is, in the direction perpendicular to the surface of the substrate 10, the two Or when the black phosphorous film layer 40 is arranged in the channel structure and is in contact with the end of the first electrode 20 close to the second electrode 30, that is, in a direction parallel to the surface of the substrate 10, the first electrode 20 and The black phosphorous film layer 40 is arranged in sequence and connected in contact.

In one embodiment of the present invention, part of the molybdenum disulfide layer 60 is disposed on the surface of the second electrode 30, or the molybdenum disulfide layer 60 is disposed in the channel structure and is in contact with the end of the second electrode 30 close to the first electrode 20. That is to say, when part of the molybdenum disulfide layer 60 is disposed on the surface of the second electrode 30, the part of the molybdenum disulfide layer 60 is directly disposed on the surface of the second electrode 30, that is, in the direction perpendicular to the surface of the substrate 10, the two Or when the molybdenum disulfide layer 60 is arranged in the channel structure and is in contact with the end of the second electrode 30 close to the first electrode 20, that is, in a direction parallel to the surface of the substrate 10, the second electrode 30 and The molybdenum disulfide layers 60 are sequentially arranged and connected in contact.

In a specific embodiment of the present invention, as shown in FIG. 1, part of the black phosphorous film layer 40 is provided on the surface of the first electrode 20, and a part of the molybdenum disulfide layer 60 is provided on the surface of the second electrode 30. The large contact area on the surface of the first electrode 20 and the large contact area between the molybdenum disulfide layer 60 and the surface of the second electrode 30 are more conducive to improving the responsiveness of the photodetector and reducing dark current. Optionally, the total thickness of the first electrode 20, the black phosphorous film layer 40 and the graphene layer 50 is equal to the thickness of the second electrode 30, thereby improving the stability of the overall structure. Optionally, the orthographic projection of the black phosphorous film layer 40 on the surface of the first electrode 20 accounts for 10%-40% of the surface area of the first electrode 20, and the orthographic projection of the molybdenum disulfide layer 60 on the surface of the second electrode 30 accounts for the second electrode. 30% of the surface area is 10%-40%, further reducing the dark current of the photodetector and improving the fast response of the photodetector. In an embodiment of the present invention, a part of the black phosphorous film layer 40 is disposed on the surface of the first electrode 20, a part of the black phosphorous film layer 40 is in contact with the substrate 10, and a part of the molybdenum disulfide layer 60 is disposed on the surface of the second electrode 30. At this time, the surface of the black phosphorous film layer 40 is not parallel to the surface of the substrate 10 and is arranged obliquely. The thickness of the first electrode 20 is on the order of nanometers, the length of the black phosphorous film layer 40 is on the order of microns, and the degree of inclination of the black phosphorous film layer 40 can be ignore. In another embodiment of the present invention, part of the black phosphorous film layer 40 is disposed on the surface of the first electrode 20, part of the molybdenum disulfide layer 60 is disposed on the surface of the second electrode 30, and part of the molybdenum disulfide layer 60 is in contact with the substrate 10. At this time, the surface of the molybdenum disulfide layer 60 is not parallel to the surface of the substrate 10 and is arranged obliquely. The thickness of the second electrode 30 is on the order of nanometers, the length of the molybdenum disulfide layer 60 is on the order of micrometers, and the degree of inclination of the molybdenum disulfide layer 60 can be ignore.

In a specific embodiment of the present invention, when the black phosphorous film layer 40 is arranged in the channel structure and is in contact with the end of the first electrode 20 close to the second electrode 30, the total of the black phosphorous film layer 40 and the graphene layer 50 The thickness is equal to the thickness of the second electrode 30 layer, and part of the molybdenum disulfide layer 60 is provided on the surface of the second electrode 30, thereby improving the stability of the overall structure.

In a specific embodiment of the present invention, when the molybdenum disulfide layer 60 is disposed in the channel structure and is in contact with the end of the second electrode 30 close to the first electrode 20, the total of the molybdenum disulfide layer 60 and the graphene layer 50 is The thickness is equal to the thickness of the first electrode 20 layer, and part of the black phosphorous film layer 40 is provided on the surface of the first electrode 20, thereby improving the stability of the overall structure.

In the present invention, the black phosphorous film layer 40, the graphene layer 50 and the molybdenum disulfide layer 60 are sequentially stacked in the channel structure, including the black phosphorous film layer 40, the graphene layer 50, and the molybdenum disulfide layer 60. Set in the channel structure, where the black phosphorous film layer 40 is closer to the substrate 10 than the graphene layer 50 and the molybdenum disulfide layer 60, or the molybdenum disulfide layer 60 is closer to the substrate than the black phosphorous film layer 40 and the graphene layer 50 10.

In one embodiment of the present invention, the overlap area of the orthographic projection of the black phosphorous film layer 40 on the substrate 10 and the orthographic projection of the molybdenum disulfide layer 60 on the substrate 10 is the same as the orthographic projection area of the graphene layer 50 on the substrate 10 The ratio is 1: (0.2-5). At this time, the black phosphorus/graphene/molybdenum disulfide heterojunction can be better used to improve the dark current of the photodetector. Further, the overlap area of the orthographic projection of the black phosphorous film layer 40 on the substrate 10 and the orthographic projection of the molybdenum disulfide layer 60 on the substrate 10 has a ratio of 1:( 1-3). Furthermore, the overlap area of the orthographic projection of the black phosphorous film layer 40 on the substrate 10 and the orthographic projection of the molybdenum disulfide layer 60 on the substrate 10 has a ratio of 1: (1-1.5), it is more conducive to photodetection, while reducing dark current and saving graphene materials. In a specific embodiment of the present invention, the overlapping area of the orthographic projection of the black phosphorous film layer 40 on the substrate 10 and the orthographic projection of the molybdenum disulfide layer 60 on the substrate 10 is the same as the orthographic projection of the graphene layer 50 on the substrate 10 The area ratio is 1:1.

In one embodiment of the present invention, the overlap area of the orthographic projection of the black phosphorous film layer 40 on the substrate 10 and the orthographic projection of the molybdenum disulfide layer 60 on the substrate 10 is completely identical to the orthographic projection of the graphene layer 50 on the substrate 10. Overlapping is more conducive to reducing the dark current of the photodetector and improving the fast response. At this time, the space charge region of the black phosphorus/graphene/molybdenum disulfide heterojunction is widened, which reduces the reverse cut-off current of the device under no light conditions, and reduces the dark current to the greatest extent.

In the present invention, the black phosphorous film layer 40, the graphene layer 50 and the molybdenum disulfide layer 60 are connected by van der Waals force to form a van der Waals force heterojunction, so that the overall structure of the photodetector is stable.

In the present invention, the channel structure includes the area between the first electrode 10 and the second electrode 20, and also includes the space above the area. In other words, the black phosphorous film layer 40, the graphene layer 50, and the molybdenum disulfide layer 60 may be laminated and disposed in the area between the first electrode 10 and the second electrode 20, or may be disposed on the first electrode 10 and the second electrode. Above the area between 20. In an embodiment of the present invention, the black phosphorous film layer 40, the graphene layer 50, and the molybdenum disulfide layer 60 are stacked in the region between the first electrode 10 and the second electrode 20.

Please refer to FIG. 2, for an embodiment of the present invention, a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction is provided. The photodetector further includes a self-healing electrode 70, which is arranged on the first The surface of an electrode 20 and/or a second electrode 30.

In the present invention, the self-healing electrode 70 is arranged on the surface of the first electrode 20 and/or the second electrode 30, and is used to prevent the occurrence of small cracks and cracks in the first electrode 20 and/or the second electrode 30. The cracks and cracks are repaired to avoid the occurrence of cracks and cracks from affecting the work of the photoelectric detector, thereby realizing the self-repairing process, and improving the service life of the photoelectric detector.

In an embodiment of the present invention, the self-healing electrode 70 includes an electrode base 72 and a self-healing layer 71, and the self-healing layer 71 is disposed on a surface of the electrode base 72 close to the first electrode 20 and/or the second electrode 30. In an embodiment of the present invention, a self-healing layer 71 is provided on all the surface of the electrode base 72. In another embodiment of the present invention, a self-healing layer 71 is provided on a surface portion of the electrode base 72. Optionally, the orthographic projection of the self-healing layer 71 on the surface of the electrode base 72 accounts for 20%-70% of the surface area of the electrode base 72. Optionally, the material of the self-healing layer 71 includes polyurethane, epoxy resin, ethylene-vinyl acetate copolymer, polyimide, polycaprolactone, polylactic acid, polyglycolic acid, polylactic acid-glycolic acid copolymer, At least one of polyvinyl alcohol and its derivatives. Specifically, the material of the self-healing layer 71 may be, but is not limited to, long-chain carbonylation modified polyurethane. Optionally, the material of the electrode base 72 includes at least one of gold, silver, platinum, copper, chromium and titanium. Further, the electrode base 72 includes an electrode connection layer and an electrode metal layer, and the electrode connection layer is in contact with the self-healing layer 71. Furthermore, the material of the electrode connection layer includes chromium and/or titanium, and the material of the electrode metal layer includes at least one of gold, silver, platinum and copper. In the present invention, the electrode connection layer is used for conducting electricity, but also has a certain connection function, so that the electrode metal layer and the self-healing layer 71 are better adhered and connected, and the bonding force between the electrode base 72 and the self-healing layer 71 is improved. . Specifically, it can be, but is not limited to, that the electrode base 72 is formed by stacking a chromium layer and a gold layer.

Please refer to FIG. 3, which is a flowchart of a method for manufacturing a photodetector based on a black phosphorus/graphene/molybdenum disulfide heterojunction according to an embodiment of the present invention, including:

S110: Provide a substrate, deposit electrode material on one surface of the substrate, and form a first electrode and a second electrode spaced apart, wherein a channel structure is formed between the first electrode and the second electrode.

In S110, the electrode material includes at least one of gold, silver, platinum, copper, chromium, and titanium. In the present invention, the materials of the first electrode and the second electrode may be the same or different, which is not limited. Optionally, the electrode material is deposited by evaporation, sputtering or ion plating. Specifically, but not limited to, the substrate is pasted on a precision silicon-based mask with electrode patterns, and then placed in an electron beam evaporator to evaporate electrode materials to obtain a substrate with blank electrode patterns. The selection of the substrate, the first electrode and the second electrode are as described above, and will not be repeated here.

S120: The black phosphorous film, the graphene film and the molybdenum disulfide film are sequentially stacked and arranged in the channel structure, and the first electrode and the second electrode are respectively contacted and connected with the black phosphorous film layer and the molybdenum disulfide layer to obtain a black phosphorous film/molybdenum disulfide film. Photodetector for graphene/molybdenum disulfide heterojunction.

In S120, the photodetector based on the black phosphorus/graphene/molybdenum disulfide heterojunction includes a substrate, a first electrode, a second electrode, a black phosphorus film layer, a graphene layer and a molybdenum disulfide layer, the first electrode and The second electrode is arranged at intervals on one side surface of the substrate, and a channel structure is formed between the first electrode and the second electrode. The black phosphorous film layer, the graphene layer and the molybdenum disulfide layer are sequentially stacked and arranged in the channel structure. The electrode and the second electrode are respectively in contact with the black phosphorous film layer and the molybdenum disulfide layer. Among them, black phosphorous film, graphene film and molybdenum disulfide film correspond to black phosphorous film layer, graphene layer and molybdenum disulfide layer in sequence. The selection of black phosphorous film layer, graphene layer and molybdenum disulfide layer is as described above, I won't repeat them here. In the present invention, black phosphorus film, graphene film, and molybdenum disulfide film can be prepared by, but not limited to, a stripping method.

In one embodiment of the present invention, the preparation method further includes: coating a self-healing material on the surface of the first electrode and/or the second electrode to form a self-healing layer; depositing electrode material on the self-healing layer to form a self-healing electrode . Wherein, the preparation process may be performed after forming the first electrode and the second electrode, or after forming at least one of the black phosphorous film layer, the graphene layer, and the molybdenum disulfide layer, which is not limited.

In a specific embodiment of the present invention, a method for preparing a photodetector based on a black phosphorous/graphene/molybdenum disulfide heterojunction includes: providing a substrate, depositing electrode materials on one side of the substrate, and forming first spaced first The electrode and the second electrode, wherein a channel structure is formed between the first electrode and the second electrode; the black phosphorous film, the graphene film and the molybdenum disulfide film are sequentially stacked in the channel structure, the first electrode and the second electrode The electrodes are in contact with the black phosphorous film and the disulfide film respectively; the self-healing material is coated on the surface of the first electrode and/or the second electrode to form a self-healing layer, and electrode material is deposited on the self-healing layer to form a self-healing electrode , A photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction is obtained. Specifically, the self-healing material may be coated on the surface edge of the first electrode and/or the second electrode to form a self-healing layer.

The photodetector based on the black phosphorus/graphene/molybdenum disulfide heterojunction provided by the present invention solves the dark current of the existing photodetector by setting the black phosphorus/graphene/molybdenum disulfide heterojunction in the photodetector Excessive problems, low dark current, fast response, high sensitivity, wide-band photoelectric detection, and the photodetector can efficiently detect visible light and infrared light at the same time, with low noise and low power consumption, which is conducive to its wide application. The preparation method of the photodetector based on the black phosphorus/graphene/molybdenum disulfide heterojunction provided by the invention is simple and easy to operate, and can produce a photodetector with low dark current and fast response.

Example 1

Paste the flexible PET substrate on a precision silicon-based mask with electrode patterns, and then put them into an electron beam evaporator to evaporate the chromium layer and the gold layer respectively. The thickness of the chromium layer is 5nm and the thickness of the gold layer is 40nm. Finally, the PET substrate is taken out to obtain a flexible PET substrate with a first electrode and a second electrode arranged at intervals. The thickness of the first electrode and the second electrode is 45nm, and a channel structure is formed between the first electrode and the second electrode. .

Use scotch tape to peel off the black phosphorous and paste it on the PDMS film, and then transfer the black phosphorous film to the flexible PET substrate on a two-dimensional material fixed-point transfer platform. The thickness of the black phosphorous film is 17nm. Similarly, use scotch tape to peel off graphene film and molybdenum disulfide film, and transfer them to a flexible PET substrate in turn. The thickness of the graphene film is 7nm, the thickness of the molybdenum disulfide film is 12nm, the black phosphorous film, graphene film and Molybdenum disulfide thin films are sequentially stacked and arranged in the channel structure to obtain a black phosphorus/graphene/molybdenum disulfide heterojunction. Part of the black phosphorus film is arranged on the surface of the first electrode, and part of the molybdenum disulfide film is arranged on the surface of the second electrode.

The self-healing material is uniformly dropped on the outer periphery of the first electrode and the second electrode, and after the film is formed, the metal hollow mask is used, and the chromium layer and the gold layer are evaporated with an electron beam evaporator to form the electrode matrix, and the self-healing electrode is obtained, which is based on Black phosphorus/graphene/molybdenum disulfide heterojunction photodetector.

Example 2

Paste the polydimethylsiloxane substrate on a precision silicon-based mask with electrode patterns, and then put it into an electron beam evaporator to vaporize the chromium layer and the gold layer, and finally the polydimethylsiloxane The substrate is taken out to obtain a polydimethylsiloxane substrate with a first electrode and a second electrode spaced apart. The thickness of the first electrode and the second electrode is 60nm, and a channel is formed between the first electrode and the second electrode structure.

Transfer the black phosphorus film, graphene film and molybdenum disulfide film to a polydimethylsiloxane substrate. The thickness of the black phosphorus film is 25nm, the thickness of the graphene film is 5nm, and the thickness of the molybdenum disulfide film is 18nm. Black phosphorus film, graphene film and molybdenum disulfide film are stacked in the channel structure in order to obtain black phosphorus/graphene/molybdenum disulfide heterojunction. The first electrode and the second electrode are respectively connected with black phosphorus film and disulfide film. Molybdenum thin film contact connection, that is, a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction is prepared.

Example 3

The flexible PET substrate is pasted on a precision silicon-based mask with electrode patterns, the first electrode and the second electrode composed of a titanium layer and a copper layer are formed by sputtering, and finally the PET substrate is taken out to obtain a spaced-apart The flexible PET substrate of the first electrode and the second electrode, the thickness of the first electrode and the second electrode is 70 nm, and a channel structure is formed between the first electrode and the second electrode.

Transfer black phosphorous film, graphene film and molybdenum disulfide film to a flexible PET substrate. The thickness of black phosphorous film is 30nm, the thickness of graphene film is 10nm, the thickness of molybdenum disulfide film is 15nm, black phosphorous film, graphite The olefin film and the molybdenum disulfide film are stacked in the channel structure in sequence. The overlap area of the orthographic projection of the black phosphorous film on the substrate and the orthographic projection of the molybdenum disulfide film on the substrate, and the orthographic projection of the graphene film on the substrate Completely overlap to obtain a black phosphorus/graphene/molybdenum disulfide heterojunction. The first electrode and the second electrode are in contact with the black phosphorus film and the molybdenum disulfide film, respectively, which is based on black phosphorus/graphene/molybdenum disulfide. Heterojunction photodetector.

Comparison

Use scotch tape to peel off the black phosphorous and paste it on the PDMS film, and then transfer the black phosphorous film to the flexible PET substrate on a two-dimensional material fixed-point transfer platform. The thickness of the black phosphorous film is 17nm. Use scotch tape to peel off the molybdenum disulfide film and transfer it to a flexible PET substrate. The thickness of the molybdenum disulfide film is 12nm. The black phosphorus film and the molybdenum disulfide film are stacked in the channel structure in order to obtain black phosphorus/molybdenum disulfide In the heterojunction, part of the black phosphorous film is arranged on the surface of the first electrode, and part of the molybdenum disulfide film is arranged on the surface of the second electrode.

The self-healing material is evenly dropped on the outer periphery of the first electrode and the second electrode. After the film is formed, the metal hollow mask is used, and the chromium layer and the gold layer are vapor-deposited with an electron beam evaporator to form the electrode matrix to obtain the self-healing electrode. Photodetector based on black phosphorus/molybdenum disulfide.

Example of effects

The photodetectors prepared in Example 1 and the comparative example were placed on the probe platform of the semiconductor characteristic analyzer, and the two probes of the probe station were selected to contact the first electrode and the second electrode of the detector respectively. Self-healing electrode. Open the semiconductor characteristic analyzer test software, select the voltage scan mode for the drain probe, and the scan range is -1V to 1V. Run the test software to get the IV diagram of the detector in the absence of light. Introduce a 655nm laser, adjust its power intensity to 150mW/cm ² , irradiate it vertically on the photodetector, set the voltage of the first electrode to 1V and the voltage of the second electrode to 0V, run the software to get the time-dependent light on and off Graph of It. The results are shown in Figure 4 and Figure 5, where Figure 4 is the test result diagram of the photodetector based on the black phosphorus/graphene/molybdenum disulfide heterojunction provided in Example 1, and Figure 4 (a) is without The IV curve diagram under light conditions shows that the photodetector has a significant rectification effect, and the dark current is very small when the voltage is reverse biased; Figure 4 (b) is the It curve diagram when there is no light and there is light alternately. It can be seen that the ratio of the current when there is light to the current when there is no light is large, indicating that the sensitivity of the photodetector is high. Fig. 5 is a graph of the test results of a photodetector based on black phosphorous/molybdenum disulfide provided by the comparative example of the present invention. (a) in Fig. 5 is an IV curve graph under non-light conditions. It can be seen that the rectification effect is not obvious. The dark current is very large when the voltage is reverse biased; Figure 5 (b) is the It curve when there is no light and there is light alternately. It can be seen that the ratio of the current when there is light to the current when there is no light is very small. Indicates that the sensitivity of the photodetector is low. Therefore, the photodetector based on the black phosphorus/graphene/molybdenum disulfide heterojunction provided by the present invention can significantly reduce the dark current of the photodetector, improve the sensitivity of the photodetector, and enable it to respond quickly.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

A photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction, which is characterized in that it comprises a substrate, a first electrode, a second electrode, a black phosphorus film layer, a graphene layer and a molybdenum disulfide layer. The first electrode and the second electrode are arranged on one side surface of the substrate at intervals, a channel structure is formed between the first electrode and the second electrode, the black phosphorous film layer, the graphene The layer and the molybdenum disulfide layer are sequentially stacked and arranged in the channel structure, and the first electrode and the second electrode are respectively in contact with the black phosphorous film layer and the molybdenum disulfide layer.
8. The photodetector according to claim 1, further comprising a self-healing electrode, and the self-healing electrode is arranged on the surface of the first electrode and/or the second electrode.
The photodetector according to claim 2, wherein the self-healing electrode comprises an electrode base and a self-healing layer, and the self-healing layer is arranged on the electrode base close to the first electrode and/or the One side surface of the second electrode.
The photodetector according to claim 1, wherein the overlapping area of the orthographic projection of the black phosphorous film layer on the substrate and the orthographic projection of the molybdenum disulfide layer on the substrate is identical to that of the orthographic projection of the molybdenum disulfide layer on the substrate. The ratio of the orthographic projection area of the graphene layer on the substrate is 1: (0.2-5).
The photodetector according to claim 1, wherein the overlapping area of the orthographic projection of the black phosphorous film layer on the substrate and the orthographic projection of the molybdenum disulfide layer on the substrate is identical to that of the orthographic projection of the molybdenum disulfide layer on the substrate. The orthographic projections of the graphene layer on the substrate completely overlap.
The photodetector according to claim 1, wherein the thickness of the black phosphorous film layer is 0.5nm-50nm, the thickness of the graphene layer is 0.3nm-15nm, and the thickness of the molybdenum disulfide layer It is 0.6nm-50nm.
The photodetector according to claim 1, wherein part of the black phosphorous film layer is disposed on the surface of the first electrode, and part of the molybdenum disulfide layer is disposed on the surface of the second electrode.
The photodetector according to claim 1, wherein the material of the substrate comprises at least one of polyethylene terephthalate, polyethylene naphthalate and polydimethylsiloxane In one type, the material of the first electrode and the second electrode includes at least one of gold, silver, platinum, copper, chromium and titanium.
A preparation method of a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction, characterized in that it comprises:

Providing a substrate, depositing electrode material on one side surface of the substrate to form a first electrode and a second electrode arranged at intervals, wherein a channel structure is formed between the first electrode and the second electrode;

A black phosphorus film, a graphene film, and a molybdenum disulfide film are sequentially stacked and arranged in the channel structure, and the first electrode and the second electrode are in contact with the black phosphorus film and the molybdenum disulfide film, respectively Connected to obtain a photodetector based on black phosphorus/graphene/molybdenum disulfide heterojunction.
9. The preparation method of claim 9, further comprising:

Coating a self-healing material on the surface of the first electrode and/or the second electrode to form a self-healing layer;

An electrode material is deposited on the self-healing layer to form a self-healing electrode.