阅读说明：本技术 一种基于二维材料的光电探测器及其制备方法 (Photoelectric detector based on two-dimensional material and preparation method thereof ) 是由 吴章婷 曾培宇 汪曾达 张阳 郑鹏 郑梁 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种基于二维半导体的光电探测器及其制备方法,至少包括衬底层、设置在该衬底层上的绝缘层、在该绝缘层上形成的异质结构以及分别与该异质结构源极和漏极相连接的电极,其中,所述异质结构至少包括二硒化钨层、石墨烯层和二硫化铼层,所述二硒化钨层、石墨烯层和二硫化铼层形成的接触均为范德瓦尔斯接触,三者的堆叠构成异质结；所述二硒化钨层位于底层,完全与绝缘层接触；所述石墨烯层置于中间层,所述二硫化铼层置于顶层,所述二硒化钨层和二硫化铼层经石墨烯层隔离而相互不接触。采用本发明的技术方案,能够实现高灵敏、宽波段和极化敏感的光波探测。(The invention discloses a photoelectric detector based on a two-dimensional semiconductor and a preparation method thereof, and the photoelectric detector at least comprises a substrate layer, an insulating layer arranged on the substrate layer, a heterostructure formed on the insulating layer and electrodes connected with a source electrode and a drain electrode of the heterostructure respectively, wherein the heterostructure at least comprises a tungsten diselenide layer, a graphene layer and a rhenium disulfide layer, contacts formed by the tungsten diselenide layer, the graphene layer and the rhenium disulfide layer are Van der Waals contacts, and the three layers are stacked to form a heterojunction; the tungsten diselenide layer is positioned on the bottom layer and is completely contacted with the insulating layer; the intermediate level is placed in to graphite alkene layer, the top layer is placed in to the rhenium disulfide layer, tungsten diselenide layer and rhenium disulfide layer are kept apart through graphite alkene layer and are not contacted each other. By adopting the technical scheme of the invention, high-sensitivity broadband and polarization-sensitive optical wave detection can be realized.)

1. A photodetector based on a two-dimensional semiconductor is characterized by at least comprising a substrate layer (1), an insulating layer (2) arranged on the substrate layer (1), a heterostructure formed on the insulating layer (2), and electrodes (3) respectively connected with a source electrode and a drain electrode of the heterostructure, wherein the heterostructure at least comprises a tungsten diselenide layer (4), a graphene layer (5) and a rhenium disulfide layer (6), contacts formed by the tungsten diselenide layer (4), the graphene layer (5) and the rhenium disulfide layer (6) are Van der Waals contacts, and the three are stacked to form a heterojunction; the tungsten diselenide layer (4) is positioned at the bottom layer and is completely contacted with the insulating layer (2); the intermediate level is placed in graphite alkene layer (5), the top layer is placed in rhenium disulfide layer (6), tungsten diselenide layer (4) and rhenium disulfide layer (6) are kept apart through graphite alkene layer (5) and are not contacted each other.

2. A two-dimensional semiconductor-based photodetector according to claim 1, characterized in that the tungsten diselenide layer (4) and the rhenium disulfide layer (6) are multi-layered and the graphene layer (5) is few-layered.

3. A two-dimensional semiconductor-based photodetector as claimed in claim 2, characterized in that said tungsten diselenide layer (4) is at least 8 or more layers; the graphene layer (5) is 2-5 layers.

4. A two-dimensional semiconductor-based photodetector according to claim 3, characterized in that the electrode (3) is of Au with a purity of 99.99%.

5. A two-dimensional semiconductor-based photodetector according to claim 4, characterized in that the thickness of the electrode (3) is 100 nm.

6. A two-dimensional semiconductor-based photodetector according to claim 3, characterized in that the insulating layer (2) is SiO₂An insulating layer.

7. A two-dimensional semiconductor-based photodetector according to claim 6, characterized in that the thickness of the insulating layer (2) is 300 nm.

8. A two-dimensional semiconductor-based photodetector according to claim 3, characterized in that said substrate layer (1) is of strong p-type Si.

9. A preparation method of a two-dimensional semiconductor-based photoelectric detector is characterized by comprising the following steps:

step S1: wiping the silicon dioxide sheet with acetone, and heating in a heating table at 250 deg.C for 30 min;

step S2: by mechanical stripping on SiO₂Obtaining multiple layers of WSe on a substrate₂；

Step S3: transfer of graphene to WSe using PDMS₂The above step (1);

step S4: soaking in acetone for 1h, and heating at 200 deg.C under 99% Ar gas atmosphere for 1 h;

step S5: recycling of PDMS for the multilayer ReS₂Transferring to graphene, and repeating step S4;

step S6: transferring the 100nm Au electrode obtained by electron evaporation to a device by using a tungsten probe under an optical microscope as a source electrode and a drain electrode;

step S7: and heating the prepared device for 1h in an Ar gas environment with the temperature of 200 ℃ and the concentration of 99% to obtain the photoelectric detector.

10. The method of claim 9, wherein the bottom layer of the prepared photodetector is a p-type two-dimensional semiconductor WSe₂The top layer is an n-type two-dimensional semiconductor ReS₂Forming a built-in electric field in space; when illuminated, WSe₂Gr and ReS₂The photogenerated carriers in (1) are rapidly separated.

Technical Field

The invention relates to the field of photoelectronic functional devices, in particular to a high-sensitivity broadband photoelectric detector based on a two-dimensional semiconductor and a preparation method thereof.

Background

Since the discovery of graphene in 2004, two-dimensional materials having a layered structure, such as graphene, hexagonal boron nitride (h-BN), Transition Metal Dichalcogenides (TMDs), Black Phosphorus (BP), etc., gradually come into the field of view, which tend to exhibit unique properties compared to bulk materials. However, a single two-dimensional material is often limited in application, for example, charge traps between an insulating layer and graphene or TMDs can seriously affect the exhibition of excellent electrical properties, h-BN with too wide band gap (about 5.97eV) is difficult to be applied in a device alone, and bare BP is easily oxidized in air to cause performance degradation. In order to deeply study the intrinsic properties of materials and expand the application fields thereof, researchers have focused on two-dimensional material heterojunctions. The two-dimensional material heterojunction is formed by two-dimensional materials through in-plane splicing or interlayer stacking and mainly comprises a graphene/h-BN heterojunction, a TMDS/graphene heterojunction, a TMDS/TMDS heterojunction and the like. In the vertical heterojunction, the graphene/h-BN vertical heterojunction mainly utilizes h-BN to reduce charge traps between an insulating layer and graphene and improve the mobility of carriers in the graphene; the TMDS/graphene vertical heterojunction mainly combines the light responsiveness of TMDS and the high conductivity of graphene and is applied to a high-performance light response device; the TMDS/TMDS vertical heterojunction mainly combines two different energy band structures of materials to control the transmission behavior of carriers and realize the optical response of storage or high performance.

To achieve polarization sensitive photodetection, anisotropic materials can be introduced into the heterostructure. ReS₂Has a high degree of planar anisotropy and stability in air, which has proven its application in polarization sensitive detectors. Currently, various heterostructure photodetectors are reported, such as TMD/TMD. Although TMD/TMD, e.g. WSe₂/MoS₂，ReS₂/WSe₂And MoTe₂/MOS₂However, the responsivity in the Near Infrared Region (NIR) is low due to the limitation of the band gap.

Therefore, it is necessary to provide a technical solution to solve the technical problems of the prior art.

Disclosure of Invention

In view of the above, it is necessary to provide a two-dimensional semiconductor-based photodetector and a method for manufacturing the same, which can implement high-sensitivity, broadband and polarization-sensitive optical wave detection.

In order to solve the technical problems in the prior art, the technical scheme of the invention is as follows:

a photoelectric detector based on a two-dimensional semiconductor at least comprises a substrate layer, an insulating layer arranged on the substrate layer, a heterostructure formed on the insulating layer and electrodes connected with a source electrode and a drain electrode of the heterostructure respectively, wherein the heterostructure at least comprises a tungsten diselenide layer, a graphene layer and a rhenium disulfide layer, contacts formed by the tungsten diselenide layer, the graphene layer and the rhenium disulfide layer are Van der Waals contacts, and the three layers are stacked to form a heterojunction; the tungsten diselenide layer is positioned on the bottom layer and is completely contacted with the insulating layer; the intermediate level is placed in to graphite alkene layer, the top layer is placed in to the rhenium disulfide layer, tungsten diselenide layer and rhenium disulfide layer are kept apart through graphite alkene layer and are not contacted each other.

As a further improvement, the tungsten diselenide layer and the rhenium disulfide layer are multiple layers, and the graphene layer is few layers.

As a further improvement, the tungsten diselenide layer has at least 8 layers; the graphene layers are 2-5 layers.

As a further improvement, the electrode adopts Au with the purity of 99.99%.

As a further improvement, the thickness of the electrode is 100 nm.

As a further improvement, the insulating layer is SiO₂An insulating layer.

As a further improvement, the thickness of the insulating layer is 300 nm.

As a further improvement, the substrate layer is made of strong p-type Si.

The invention also discloses a preparation method of the photoelectric detector based on the two-dimensional semiconductor, which comprises the following steps:

step S1: wiping the silicon dioxide sheet with acetone, and heating in a heating table at 250 deg.C for 30 min;

step S2: by mechanical stripping on SiO₂Obtaining multiple layers of WSe on a substrate₂；

Step S3: transfer of graphene to WSe using PDMS₂The above step (1);

step S4: soaking in acetone for 1h, and heating at 200 deg.C under 99% Ar gas atmosphere for 1 h;

step S5: recycling of PDMS for the multilayer ReS₂Transferring to graphene, and repeating step S4;

step S6: transferring the 100nm Au electrode obtained by electron evaporation to a device by using a tungsten probe under an optical microscope as a source electrode and a drain electrode;

step S7: and heating the prepared device for 1h in an Ar gas environment with the temperature of 200 ℃ and the concentration of 99% to obtain the photoelectric detector.

As a further improvement scheme, the bottom layer of the prepared photoelectric detector is a p-type two-dimensional semiconductor WSe₂The top layer is an n-type two-dimensional semiconductor ReS₂Forming a built-in electric field in space; when illuminated, WSe₂Gr and ReS₂The photogenerated carriers in (1) are rapidly separated.

Compared with the prior art, the invention adopts three different materials to be stacked to form a heterojunction, the upper layer and the lower layer are made of different types of semiconductor materials, the middle layer is made of a material with zero band gap or narrow band gap, and the materials in the upper layer and the lower layer have anisotropic characteristics. Prepared ReS₂/Graphene/WSe₂The photoelectric detector can realize high-sensitivity, broadband and polarization-sensitive light wave detection.

Drawings

FIG. 1 shows the present invention ReS₂/Gr/WSe₂A heterojunction structure diagram, wherein: 1 is a silicon substrate holder; 2 is an insulating layer(ii) a 3 is an electrode; 4 is a tungsten diselenide layer; 5 is a graphene layer; 6 is a rhenium disulfide layer;

FIG. 2 shows the resulting ReS₂/Gr/WSe₂An optical picture of a heterojunction photodetector;

FIG. 3 is a graph of the output of the photodetector of the present invention at different gate voltages;

FIG. 4 is a graph of the optical response of the optical detector of the present invention as a function of the polarization direction of light;

FIG. 5 is a switching characteristic of the photodetector of the present invention;

the following specific embodiments will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

The technical solution provided by the present invention will be further explained with reference to the accompanying drawings.

In the research, the applicant finds that the TMD/Graphene/TMD is manufactured by stacking the n-type TMD, the Graphene and the p-type TMD, and the zero-band-gap Graphene is introduced as broadband light absorption, so that the responsivity in the near infrared can be effectively improved. However, the performance of photodetection is yet to be further improved.

Aiming at the technical problem, the invention provides a two-dimensional semiconductor-based photoelectric detector which at least comprises a substrate layer (1), an insulating layer (2) arranged on the substrate layer (1), a heterostructure formed on the insulating layer (2) and electrodes (3) connected with a source electrode and a drain electrode of the heterostructure respectively, wherein the heterostructure at least comprises a tungsten diselenide layer (4), a graphene layer (5) and a rhenium disulfide layer (6), contacts formed by the tungsten diselenide layer (4), the graphene layer (5) and the rhenium disulfide layer (6) are Van der Waals contacts, and the three are stacked to form a heterojunction; the tungsten diselenide layer (4) is positioned at the bottom layer and is completely contacted with the insulating layer (2); the intermediate level is placed in graphite alkene layer (5), the top layer is placed in rhenium disulfide layer (6), tungsten diselenide layer (4) and rhenium disulfide layer (6) are kept apart through graphite alkene layer (5) and are not contacted each other.

As a further improvement scheme, the tungsten diselenide layer (4) and the rhenium disulfide layer (6) are multiple layers, and the graphene layer (5) is few layers.

As a further improvement, the tungsten diselenide layer (4) is at least more than 8 layers; the graphene layer (5) is 2-5 layers.

As a further improvement, the electrode (3) is made of Au with the purity of 99.99 percent.

As a further improvement, the insulating layer (2) is SiO₂An insulating layer.

As a further improvement, the substrate layer (1) is made of strong p-type Si.

By adopting the technical scheme, the formed ReS₂/Graphene(Gr)/WSe₂The heterojunction has the following technical effects:

1.ReS₂has high plane anisotropy and has different optical response to polarized light in different directions. It has this property retained in the ReS₂/Gr/WSe₂In the heterojunction, the result is that the heterojunction is sensitive to the polarization of light.

2. Bottom layer p-type two-dimensional semiconductor WSe₂Top n-type two-dimensional semiconductor ReS₂A built-in electric field is formed in space. WSe under illumination condition due to existence of built-in electric field₂Gr and ReS₂The photogenerated carriers in (1) can be separated rapidly, and high sensitivity is obtained. Meanwhile, the action of a built-in electric field and the self characteristics of the heterojunction can greatly suppress dark current and improve the detection rate.

3. Using multiple layers of ReS₂And WSe₂This is because the multiple layers increase the light absorption, and the use of the small number of layers Gr is because the small number of layers Gr is easily available and has the energy band characteristics of zero band gap.

4. ReS with band gaps of about 1.45eV and 1.25eV₂And WSe₂The visible light can be absorbed, and photo-generated carriers are generated to improve the photoresponse. For zero bandgap Gr, its light absorption range is wide, from the visible to the infrared. Therefore, ReS₂/Gr/WSe₂The heterojunction has optical response from visible light to infrared light, and proves that the heterojunction has optical detection with wide waveband, wherein the ReS₂Gr and WSe₂Contributes to visible light response, and only contributes to Gr in an infrared band.

The invention also discloses a preparation method of the photoelectric detector based on the two-dimensional semiconductor, which comprises the following steps:

step S1: wiping the silicon dioxide sheet with acetone, and heating in a heating table at 250 deg.C for 30 min;

step S2: by mechanical stripping on SiO₂Obtaining multiple layers of WSe on a substrate₂；

Step S3: transfer of graphene to WSe using PDMS₂The above step (1);

step S4: soaking in acetone for 1h, and heating at 200 deg.C under 99% Ar gas atmosphere for 1 h;

step S5: recycling of PDMS for the multilayer ReS₂Transferring to graphene, and repeating step S4;

step S6: transferring the 100nm Au electrode obtained by electron evaporation to a device by using a tungsten probe under an optical microscope as a source electrode and a drain electrode;

step S7: and heating the prepared device for 1h in an Ar gas environment with the temperature of 200 ℃ and the concentration of 99% to obtain the photoelectric detector.

The photodetector comprises 6 parts, namely a substrate layer, a gold electrode, a tungsten diselenide layer, a graphene layer and a rhenium disulfide layer. Silicon substrate base, SiO₂The thickness of the insulating layer is 300nm, the electrode adopts 100nm Au with the purity of 99.99 percent, the rhenium sulfide and the tungsten diselenide adopt a plurality of layers (more than 8 layers), and the graphene adopts a few layers (2-5 layers). Wherein, the multilayer tungsten diselenide is positioned at the bottom layer and is completely connected with SiO₂Substrate contact; few layers of graphene are arranged in the middle layer, multiple layers of rhenium disulfide are arranged on the top layer, and tungsten diselenide on the bottom layer is not in contact with rhenium disulfide on the top layer. The contacts formed by the tungsten diselenide, the graphene and the rhenium disulfide are Van der Waals contacts, and the three are stacked to form a heterojunction.

FIG. 2 shows the resulting ReS₂/Gr/WSe₂An optical picture of a heterojunction photodetector; fig. 3 shows the output curves at different gate voltages. Obvious rectification effect can be seen, and the fact that an effective built-in electric field is formed inside the prepared heterojunction is proved. The direction of the polarized light is adjusted by rotating the half-wave plate, and the light response of different polarized light is obtained, as shown in fig. 4. Illustrating the light-focusing pole of the light detectorThe polarization sensor is sensitive and can be used for polarization sensitivity. In fig. 5, it can be seen that the device has an ultra-fast optical response. Using an expression for responsivity:wherein I_phThe responsivity of the photoelectric detector can be calculated by taking the photocurrent, S as the area of the detector and P as the incident laser power. And by the expression of external quantum efficiency and detectivity:andand calculating to obtain the external quantum efficiency and detectivity.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.