阅读说明：本技术 一种硫化钼-石墨烯异质结光电导探测器及其制备方法 (Molybdenum sulfide-graphene heterojunction photoconductive detector and preparation method thereof ) 是由 慕飒米 张少先 刘永 杜明 李侠 于 2019-09-04 设计创作，主要内容包括：本发明涉及一种硫化钼-石墨烯异质结光电导探测器及其异质结的制备方法,包括异质结,所述异质结包括设置在SiO<Sub>2</Sub>/Si衬底层上的MoS<Sub>2</Sub>层,所述MoS<Sub>2</Sub>层上设置有石墨烯层,所述石墨烯层上设置有若干个金属电极。本发明提供了一种具有低成本、高响应度的二维材料异质结负光电导探测器及其制备方法；通过采用二维材料转移技术,减少石墨烯/TMDC异质结界面层杂质问题,提高石墨烯/TMDC光导型探测器的光电特性。(The invention relates to a molybdenum sulfide-graphene heterojunction photoconductive detector and a preparation method of a heterojunction thereof 2 MoS on/Si substrate layer 2 Layer of said MoS 2 Be provided with graphite alkene layer on the layer, be provided with a plurality of metal electrode on the graphite alkene layer. The invention provides a two-dimensional material heterojunction negative photoconductive detector with low cost and high responsivity and a preparation method thereof; by adopting a two-dimensional material transfer technology, the problem of impurity of a graphene/TMDC heterojunction interface layer is reduced, and the photoelectric characteristic of the graphene/TMDC photoconductive detector is improved.)

1. The utility model provides a molybdenum sulfide-graphite alkene heterojunction photoconduction detector, includes the heterojunction, its characterized in that: the heterojunction comprises a silicon oxide layer arranged on SiO₂MoS on a Si substrate layer (1)₂Layer (2), said MoS₂The graphene layer (3) is arranged on the layer (2), and the plurality of metal electrodes (4) are arranged on the graphene layer (3).

2. The molybdenum sulfide-graphene heterojunction photoconductive detector of claim 1, wherein: 2 metal electrodes (4) are arranged on the graphene layer (3), and the metal electrodes (4) are made of Ag.

3. The molybdenum sulfide-graphene heterojunction photoconductive detector of claim 3, wherein: the SiO₂the/Si substrate layer (1) comprises a layer arranged on the MoS₂SiO under layer (2)₂A layer (12), and a layer disposed on the SiO₂A Si layer (11) under the layer (12).

4. The method for preparing molybdenum sulfide-graphene heterojunction in photoconductive detector as in any of claims 1 ~ 3 wherein:

step one, MoS₂The layer (2) is transferred by a Polydimethylsiloxane (PDMS) dry transfer mode; utilizing polydimethylsiloxane PDMS and MoS₂Greater than MoS₂Adhesion to sapphire, thereby MoS₂From MoS₂Sapphire of the original substrate in Sapphire is peeled off and transferred to the desired SiO₂Forming MoS on/Si substrate layer (1)₂/SiO₂a/Si layer;

step two, the graphene layer (3) is transferred and mainly assembled by using a vacuum hot-pressing system; in order to prepare the heterojunction, the graphene thin film needs to be transferred to MoS₂/SiO₂MoS on the/Si layer₂Of layer (2)The surface is used as a graphene layer (3) to form graphene/MoS₂/SiO₂a/Si layer;

step three; in graphene/MoS₂/SiO₂A metal electrode (4) made of Ag is arranged on the graphene layer (3) of the/Si layer and is formed on the SiO layer by a thermal evaporation technology₂Ag/graphene/MoS on/Si substrate layer (1)₂And (3) heterojunction devices, and testing the photoelectric performance of the heterojunction devices by using a photoelectric detector testing system.

5. The method for preparing a molybdenum sulfide-graphene heterojunction in a photoconductive detector as claimed in claim 4, wherein: in the first step, the dry transfer method comprises the specific steps of firstly shearing the prepared polydimethylsiloxane PDMS into rectangular blocks, and flatly pressing the rectangular blocks on MoS₂The mixture was allowed to stand for 1 ~ 10min on a Sapphire surface using PDMS and MoS₂Greater than MoS₂The adhesion to sapphire is slightly lifted from the PDMS side, MoS₂Remaining on PDMS to form PDMS/MoS₂A layer; then adding PDMS/MoS₂Layer bonding to SiO₂Baking at 40 deg.C and ~ 60 deg.C and 60 deg.C for 3 ~ 8 min on Si substrate layer (1) to release polydimethylsiloxane PDMS and MoS₂/SiO₂The adhesion between/Si and easy stripping of PDMS to MoS₂Layer (2) transfer to SiO₂On the/Si substrate layer (1), MoS is completed₂Transfer of layer (2) to form MoS₂/SiO₂A layer of/Si.

6. The method for preparing the molybdenum sulfide-graphene heterojunction device in the photoconductive detector as claimed in claim 4, wherein the graphene layer (3) is transferred in a vacuum hot-pressing system, and comprises the following specific steps of fixing one side of a graphene/Cu layer on a Glass slide by using a high-temperature adhesive tape, wherein the other side of the graphene layer (3) faces outwards, mounting the graphene layer on a vacuum support table below the top of the vacuum support table, arranging a cavity below the vacuum support table, placing a target substrate MoS2/SiO2/Si layer on the cavity bottom of the cavity, heating the cavity bottom to 180 ~ 220 ℃, vacuumizing the cavity to 120 ~ 180mTorr, slowly lowering the support table to enable the Glass/Cu/graphene to be in contact with the MoS2/SiO2/Si layer, keeping the temperature for 10 ~ 25min, lowering the temperature of the cavity bottom to 30 ~ 50 ℃, slowly lifting the vacuum support table, and transferring the graphene layer (3) to the MoS2/SiO2/Si layer surface to form the graphene/MoS 2/SiO2/Si layer.

Technical Field

The invention belongs to the field of photoconductive detectors, and particularly relates to a structure of a molybdenum sulfide-graphene heterojunction photoconductive detector represented by graphene and transition metal sulfide with low cost and high responsivity and a preparation method of a heterojunction of the structure.

Background

A photoconductive detector is a device that converts a light pulse in an optical fiber or waveguide into an electrical signal. Has very important function in the technical field of integrated electronics.

Heterojunction, an interface region formed by two different semiconductors contacting each other. The heterojunction can be divided into homotype heterojunction (P-P junction or N-N junction) and heterotype heterojunction (P-N or P-N) according to the conduction types of the two materials, and the multilayer heterojunction is called as heterostructure. The conditions for forming a heterojunction are typically that the two semiconductors have similar crystal structures, close atomic spacings, and coefficients of thermal expansion. Heterojunctions can be fabricated using techniques such as interfacial alloying, epitaxial growth, vacuum deposition, and the like. The heterojunction has excellent photoelectric characteristics which cannot be achieved by respective PN junctions of two semiconductors, so that the heterojunction is suitable for manufacturing ultrahigh-speed switching devices, solar cells, semiconductor lasers and the like.

With the rapid development of the information era, the photoelectric detector for transmitting optical signal information at a high speed and collecting the information plays an increasingly important role, and has important application in the fields of information transmission, video imaging, safety security, atmospheric sensors, biomedicine and the like. With the continuous expansion of the application scale, the requirement for faster, more efficient and wider wavelength range detection becomes a problem to be solved in the photoelectric detector. Compared with a photovoltaic device, the light guide device has the advantages of simple structure, high responsiveness and easy realization in the aspect of preparation.

The graphene has an ultrathin monoatomic layer structure, high electron mobility and extremely wide electromagnetic wave absorption spectrum, so that the ultra-wide band detection of ultraviolet and even middle and far infrared can be realized by the optical detector based on the graphene, for example, the responsivity of the infrared band reaches 6.1mA/W when the graphene film is used for T.Mueller and other [1] people to prepare the infrared optical detector. However, graphene has a zero band gap structure and low light absorption rate, so that the responsivity of the device is low. The other kind of graphene two-dimensional material transition metal sulfide (TMDC) has a band gap adjustable structure and stronger light absorption rate, so that the structure of graphene and TMDC are combined to form a heterojunction, and the structure has certain significance for enhancing the photoelectric effect of a device. High mass transfer is one of the keys to the construction of two-dimensional material heterojunctions and their flexible device applications. However, the two-dimensional material (such as graphene) after transfer often has problems of wrinkling, cracking and the like, thereby affecting the photoelectric performance of the two-dimensional material detector. Therefore, the problems of impurity defects and the like generated in the transfer process are reduced, and the improvement of the device performance is very important.

Therefore, in order to solve the problems in the prior art, a molybdenum sulfide/graphene two-dimensional material heterojunction negative photoconductive detector with low cost and high responsivity and a preparation method thereof need to be developed. By adopting a two-dimensional material transfer technology, the problem of impurity of a graphene/TMDC heterojunction interface layer is reduced, and the photoelectric characteristic of the graphene/TMDC photoconductive detector is improved.

Disclosure of Invention

The invention overcomes the defects of the prior art and provides the molybdenum sulfide and graphene heterojunction photoconductive detector with low cost and high responsivity and the preparation method thereof. By adopting a two-dimensional material transfer technology, the problem of impurity of a graphene/TMDC heterojunction interface layer is reduced, and the photoelectric characteristic of the graphene/TMDC photoconductive detector is improved.

In order to achieve the purpose, the invention adopts the technical scheme that: a molybdenum sulfide-graphene heterojunction photoconductive detector comprises a heterojunction, wherein the heterojunction is arranged on SiO₂MoS on/Si substrate layer₂Layer of said MoS₂Be provided with graphite alkene layer on the layer, be provided with a plurality of metal electrode on the graphite alkene layer.

In a preferred embodiment of the present invention, 2 metal electrodes are disposed on the graphene layer, and the metal electrodes are made of Ag.

In a preferred embodiment of the present invention, the SiO₂the/Si substrate layer comprises a layer arranged on the MoS₂SiO under layer₂A layer, and a layer disposed on the SiO₂A Si layer below the layer.

In a preferred embodiment of the invention, the preparation method of the molybdenum sulfide-graphene heterojunction photoconductive detector comprises the following steps:

step one, MoS₂Layer transfer by polydimethylsiloxane PDMS Dry ProcessA transfer mode; utilizing polydimethylsiloxane PDMS and MoS₂Greater than MoS₂Adhesion to sapphire, thereby MoS₂From MoS₂Sapphire of the original substrate in Sapphire is peeled off and transferred to the desired SiO₂Forming MoS on/Si substrate layer₂/SiO₂A layer of/Si. In particular, polydimethylsiloxane PDMS is a polymer with better viscoelasticity commonly used for transfer.

Step two, the graphene layer transfer mainly uses a vacuum hot-pressing system to realize the assembly of the two materials; in order to prepare the heterojunction, the graphene thin film needs to be transferred to MoS₂/SiO₂MoS on the/Si layer₂The surface of the layer is used as a graphene layer to form graphene/MoS₂/SiO₂A layer of/Si. In particular, vacuum hot pressing provides a clean, wrinkle-free transfer method. In order to prepare the heterojunction, the graphene layer in the form of a thin film is transferred to the surface of molybdenum disulfide.

Step three; in graphene/MoS₂/SiO₂A metal electrode made of Ag is arranged on the graphene layer of the/Si layer and is formed on the SiO layer by a thermal evaporation technology₂Ag/graphene/MoS on/Si substrate layer₂And (3) heterojunction devices, and testing the photoelectric performance of the heterojunction devices by using a photoelectric detector testing system. Specifically, it is disposed on SiO₂Ag/graphene/MoS on/Si substrate layer₂Heterojunction devices have a significant negative photoconductive effect, in contrast to the positive photoconductive properties of conventional semiconductors.

In a preferred embodiment of the present invention, in the step one, the dry transfer method comprises the specific steps of firstly cutting the prepared polydimethylsiloxane PDMS into rectangular blocks, and flatly pressing the rectangular blocks on the MoS₂The mixture was allowed to stand for 1 ~ 10min on a Sapphire surface using PDMS and MoS₂Greater than MoS₂The adhesion to sapphire is slightly lifted from the PDMS side, MoS₂Remaining on PDMS to form PDMS/MoS₂A layer; then adding PDMS/MoS₂Layer bonding to SiO₂Baking at 40 deg.C and ~ 60 deg.C for 3 ~ 8 min on Si substrate layer to releasePolydimethylsiloxane PDMS and MoS₂/SiO₂The adhesion between/Si and easy stripping of PDMS to MoS₂Layer transfer to SiO₂On the/Si substrate layer, MoS is completed₂Transfer of layers to form MoS₂/SiO₂A layer of/Si.

In a preferred embodiment of the present invention, in the second step, the graphene layer transfer is completed in a vacuum hot-pressing system; the method comprises the following specific steps of fixing one surface of a graphene/Cu layer on a Glass slide by using a high-temperature adhesive tape, wherein the other surface of the graphene layer faces outwards, installing the graphene layer below the top of a vacuum support table, arranging a cavity below the vacuum support table, and placing a target substrate MoS at the bottom of the cavity₂/ SiO₂Heating the cavity bottom to 180 ~ 220 ℃, vacuumizing the cavity to 120 ~ 180mTorr, slowly lowering the support table to enable Glass/Cu/graphene to be in contact with the MoS2/SiO2/Si layer, keeping the temperature for 10 ~ 25min, reducing the temperature of the cavity bottom to 30 ~ 50 ℃, slowly lifting the vacuum support table, and transferring the graphene layer (3) to the surface of the MoS2/SiO2/Si layer to form the graphene/MoS 2/SiO2/Si layer.

The invention solves the defects existing in the background technology, and has the beneficial effects that:

the invention provides a molybdenum sulfide-graphene heterojunction photoconductive detector with low cost and high responsivity and a preparation method thereof; by adopting a two-dimensional material transfer technology, the problem of impurity of a graphene/TMDC heterojunction interface layer is reduced, and the photoelectric characteristic of the graphene/TMDC photoconductive detector is improved. The molybdenum sulfide-graphene heterojunction photoconductive detector in the patent has an obvious negative photoconductive effect. The two-dimensional material transfer technology is the key for constructing the two-dimensional material heterojunction device, and the material transfer technology in the process of preparing the detector is emphasized and particularly required in the patent.

According to the preparation method of the molybdenum sulfide-graphene heterojunction photoconductive detector, heterojunction preparation is mainly completed through dry transfer. Dry transfer is achieved under certain conditions mainly by means of the physical adsorption principle. Compared with the wet transfer, the dry transfer does not introduce any chemical liquid in the transfer process, thereby avoiding chemical pollution and better ensuring the cleanness of the surface of the transferred material and no residue.

The graphene/MoS dry transfer method realizes low cost and simple and easy realization by using a two-dimensional material dry transfer technology₂Preparation technology of heterojunction photoelectric detector.

By testing graphene/MoS₂The heterojunction has photoelectric characteristics, and is found to have a remarkable negative photoconductive effect. The responsivity reaches 10.5A/W at 650nm wavelength.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a molecular structure diagram of a molybdenum sulfide and graphene heterojunction photoconductive detector of the invention.

FIG. 2 is a photoelectric test I-V curve of the molybdenum sulfide and graphene heterojunction photoconductive detector of the invention.

FIG. 3 is a photoelectric test I-T curve of the molybdenum sulfide and graphene heterojunction photoconductive detector of the invention.

Wherein, 1-SiO₂Substrate layer of/Si, layer of 11-Si, layer of 12-SiO₂Layer, 2-MoS₂Layer, 3-graphene layer, 4-metal electrode.

Detailed Description

For a better understanding of the invention by those skilled in the art, the invention is described in further detail below with reference to the accompanying drawings and examples.

The embodiments described below are only a part of the embodiments of the present invention, and not all of them; based on the embodiments of the present invention, other embodiments used by those skilled in the art without any creative effort belong to the protection scope of the present invention.

As shown in FIG. 1, the embodiment discloses a molybdenum sulfide-graphene heterojunction photoconductive detector, which comprises a heterojunction, wherein the heterojunction is arranged on SiO₂MoS on/Si substrate layer 1₂ Layer 2, MoS₂Be provided with graphite alkene layer 3 on layer 2, be provided with 2 metal electrode 4 that Ag made on graphite alkene layer 3. SiO2₂the/Si substrate layer 1 comprisesIs arranged at MoS₂SiO under layer 2₂ Layer 12, and is disposed on SiO₂ Si layer 11 under layer 12.

The preparation method of the molybdenum sulfide-graphene heterojunction photoconductive detector comprises the following steps:

step one, MoS₂The layer 2 is transferred by a polydimethylsiloxane PDMS dry transfer mode; utilizing polydimethylsiloxane PDMS and MoS₂Greater than MoS₂Adhesion to sapphire, thereby MoS₂From MoS₂Sapphire of the original substrate in Sapphire is peeled off and transferred to the desired SiO₂MoS formation on a/Si substrate layer 1₂/SiO₂A layer of/Si.

The dry transfer method comprises the specific steps of firstly cutting the prepared polydimethylsiloxane PDMS into rectangular blocks, in one embodiment of the invention, cutting the polydimethylsiloxane PDMS into 2 cm multiplied by 2 cm, and flatly pressing the polydimethylsiloxane PDMS on MoS₂The mixture is allowed to stand for 1 ~ 10min, preferably 3min, on a Sapphire surface, and PDMS and MoS are used₂Greater than MoS₂The adhesion to sapphire is slightly lifted from the PDMS side, MoS₂Remaining on PDMS to form PDMS/MoS₂A layer; then adding PDMS/MoS₂Layer bonding to SiO₂Baking at 40 deg.C ~ 60 deg.C and 60 deg.C for 3 ~ 8 min, preferably baking at 50 deg.C for 5min to release polydimethylsiloxane PDMS and MoS on Si substrate layer 1₂/SiO₂The adhesion between/Si and easy stripping of PDMS to MoS₂Layer 2 transfer to SiO₂On the/Si substrate layer 1, MoS is completed₂Transfer of layer 2 to form MoS₂/SiO₂A layer of/Si.

Step two, the graphene layer 3 is transferred, and a vacuum hot-pressing system is mainly used for assembling the two materials; in order to prepare the heterojunction, the graphene thin film needs to be transferred to MoS₂/SiO₂MoS on the/Si layer₂The surface of layer 2 is used as graphene layer 3 to form graphene/MoS₂/SiO₂A layer of/Si.

In particular, the graphene layer 3 is transferredThe method is completed in a vacuum hot-pressing system and comprises the following specific steps: firstly, fixing one surface of a graphene/Cu layer on a Glass slide by using a high-temperature adhesive tape, wherein the other surface of the graphene layer 3 faces outwards, and installing the graphene/Cu layer below the top of a vacuum support platform, wherein a cavity is arranged below the vacuum support platform, and a target substrate MoS is placed at the cavity bottom of the cavity₂Heating the cavity bottom to 180 ~ ℃, preferably 200 ℃ in the invention, vacuumizing the cavity to 120 ~ mTorr, preferably 150 mTorr in the invention, slowly lowering the support platform to enable the Glass/Cu/graphene to be in contact with the MoS2/SiO2/Si layer, keeping for 10 ~ min, preferably 15min in the invention, reducing the temperature of the cavity bottom to 30 3650 ℃, preferably 40 ℃ in the invention, slowly lifting the vacuum support platform, and transferring the graphene layer 3 to the surface of the MoS2/SiO2/Si layer to form the graphene/MoS 2/SiO2/Si layer.

Step three; in graphene/MoS₂/SiO₂A metal electrode 4 made of Ag is arranged on the graphene layer 3 of the/Si layer and is formed on the SiO layer by a thermal evaporation technology₂Ag/graphene/MoS on/Si substrate layer 1₂And (3) heterojunction devices, and testing the photoelectric performance of the heterojunction devices by using a photoelectric detector testing system.

FIG. 2 is a photoelectric test I-V curve of a graphene/MoS 2 heterojunction photodetector. It can be seen that the metal electrode 4 contact is a typical ohmic contact and that the current is reduced under illumination and the device exhibits a significant negative photoconductive effect. FIG. 3 is a photoelectric test I-T curve of a heterojunction photoconductive detector. The current is reduced in the case of illumination, and gradually returns to a stable state in the case of no light. And the response of the heterojunction light guide detector reaches 10.2A/W when the optical power density is 0.9 mW/cm 2. The experiment constructs the heterojunction in a transfer mode, the cost is low, and the Ag/graphene/MoS 2 structure of the constructed heterojunction photoconductive detector has an obvious negative photoconductive effect, so that the method has certain guiding significance in the aspect of device application.

In light of the foregoing description of the preferred embodiment of the present invention, it is to be understood that various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.