Organic / inorganic room temperature exciton switch and preparation method and application thereof

Abstract

The invention discloses an organic / inorganic room temperature exciton switch and a preparation method and application thereof. The preparation method comprises the following steps: transferring a dielectric layer film for epitaxial growth of an organic semiconductor film on a substrate; epitaxially preparing an organic semiconductor film; lattice alignment does not need to be considered, and a single-layer transition metal disulfide thin film is transferred to an organic semiconductor thin film prepared by epitaxy to form a heterojunction; the transfer dielectric layer film is used for packaging the heterojunction; a silver microwire electrode is transferred to the structure as a gate. The exciton switch capable of effectively working at room temperature is manufactured by constructing an organic / inorganic heterojunction, the development of photoelectric equipment is expected to be promoted, and the exciton switch has potential application value in the aspect of effective interconnection between optical data transmission and electronic processing systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic components, and in particular relates to an organic / inorganic room-temperature exciton switch and a preparation method and application thereof. Background Art

[0002] Exciton devices can be used to directly process optical data streams without converting between charge current and light. This avoids problems such as energy loss and signal delay in traditional photoelectric conversion processes and improves the efficiency of optical data processing. In addition, because the typical exciton size (Bohr radius) is on the nanometer scale, exciton devices can greatly reduce the material budget of optical switches compared to some traditional optical devices such as light modulators. This compactness facilitates higher-density integration and has great potential in building miniaturized, high-performance optoelectronic devices.

[0003] Currently, coupled quantum well structures and transition metal dichalcogenide van der Waals heterojunction structures with type II band alignment are the basic structures for preparing exciton devices. Limited by the exciton binding energy of the materials themselves, exciton devices based on coupled quantum well structures can only operate at temperatures below 100K. Although single-layer transition metal dichalcogenides have large exciton binding energies and strong quantum confinement allow exciton devices based on this structure to operate at room temperature, this requires that the two layers of two-dimensional materials be lattice-aligned, otherwise the resulting moiré potential will significantly affect the diffusion of excitons. Therefore, the existing technology still needs to be improved and enhanced. Summary of the Invention

[0004] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0005] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide an organic / inorganic room temperature exciton switch.

[0007] To solve the above technical problems, the present invention provides the following technical solution: using a single-layer MoS2 thin film as the inorganic layer and a Pentacene single-crystal thin film as the organic layer, the inorganic layer and the organic layer form a heterostructure, and no lattice alignment is required to achieve exciton switching at room temperature.

[0008] As a preferred solution of the organic / inorganic room temperature exciton switch of the present invention, the structure of the exciton switch from bottom to top includes:

[0009] Substrate layer 1, made of Si / SiO2;

[0010] Dielectric layer 2, made of h-BN thin film with a thickness of 5 to 10 nm;

[0011] Organic layer 3, made of Pentacene single crystal thin film;

[0012] Inorganic layer 4, made of a single-layer MoS2 film;

[0013] Encapsulation layer 5, made of h-BN thin film with a thickness of 5 to 10 nm;

[0014] Gate layer 6, made of Ag micron wire, length > 150nm;

[0015] The light input end 7 and the light output end 8 are respectively located on both sides of the gate layer 6 .

[0016] Another object of the present invention is to provide a method for preparing an organic / inorganic room-temperature exciton switch.

[0017] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0018] Mechanically peel off a 5-10 nm thick h-BN film and transfer it to the pre-treated substrate layer 1 using a two-dimensional material transfer platform to form a dielectric layer 2 to obtain Si / SiO2 / h-BN;

[0019] Pentacene powder is used as an organic molecule source and placed in the center of the tube furnace. Si / SiO2 / h-BN is placed in the downwind area of ​​the tube furnace and evaporates to form a pentacene single crystal film, which is the organic layer 3.

[0020] By mechanically exfoliating a single-layer MoS2 film as the inorganic layer 4, a heterojunction structure is formed with the organic layer 3;

[0021] Mechanically peeling off a 5-10 nm thick h-BN film and transferring it to the surface of the formed heterojunction structure using a two-dimensional material transfer platform to form an encapsulation layer 5;

[0022] With the help of a two-dimensional material transfer platform, the silver microwires are transferred to the top of the encapsulation layer 5 to form a gate layer 6, and a light input end 7 and a light output end 8 are respectively set on both sides of the gate layer 6 to obtain an organic / inorganic room temperature exciton switch.

[0023] As a preferred solution of the preparation method of the organic / inorganic room-temperature exciton switch described in the present invention, the substrate layer material is Si / SiO2, and its pretreatment includes ultrasonic cleaning with acetone, ethanol, and deionized water liquids for 10 to 15 minutes respectively, and then blowing it dry with dry nitrogen.

[0024] As a preferred solution of the method for preparing the organic / inorganic room-temperature exciton switch of the present invention, the evaporation source temperature of the tube furnace is 160-180° C., the vacuum degree is 100-200 Pa, and the carrier gas flow rate is 60-80 sccm.

[0025] As a preferred solution of the method for preparing the organic / inorganic room-temperature exciton switch of the present invention, the growth time of the evaporation growth is 30 to 40 minutes.

[0026] As a preferred solution of the method for preparing the organic / inorganic room-temperature exciton switch of the present invention, the distance between the Si / SiO2 / h-BN and the organic molecule source is 9 to 11 cm.

[0027] As a preferred solution of the method for preparing the organic / inorganic room-temperature exciton switch of the present invention, wherein: the length of the silver microwire is greater than 150 μm.

[0028] Another object of the present invention is to provide an application of an organic / inorganic room temperature exciton switch in directly processing optical data streams.

[0029] Beneficial effects of the present invention:

[0030] The preparation method of the organic / inorganic room-temperature exciton switch of the present invention selects an organic semiconductor film with large exciton binding energy and a single-layer transition metal disulfide film to construct a heterojunction, eliminating the need for lattice alignment, simplifying the preparation of the room-temperature exciton switch, reducing process costs, facilitating the application of device preparation, and realizing exciton switching at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0032] Figure 1 Flowchart for preparing the organic / inorganic room temperature exciton switch of the present invention.

[0033] Figure 2 This is a structural diagram of an embodiment of an organic / inorganic room-temperature exciton switch prepared in the present invention.

[0034] Figure 3 This is the “on” state emission diagram of the organic / inorganic room temperature exciton switch embodiment provided in Example 2 of the present invention.

[0035] Figure 4 This is the "off" state emission diagram of the organic / inorganic room temperature exciton switch embodiment provided in Example 2 of the present invention.

[0036] Figure 5 This is an “on” state emission diagram of an organic / inorganic room temperature exciton switch embodiment provided as a comparative example of the present invention. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0040] Unless otherwise specified, the raw materials used in the present invention are commonly available in the market.

[0041] Example 1

[0042] Reference Figure 1 This embodiment provides a method for preparing an organic / inorganic room temperature exciton switch, specifically:

[0043] S1: transferring a dielectric layer film for epitaxial growth of an organic semiconductor film on a substrate;

[0044] The h-BN film with a thickness of 5 to 10 nm was mechanically exfoliated and transferred onto a Si / SiO2 substrate using a two-dimensional material transfer platform, and used as an epitaxial growth layer for the organic semiconductor film, denoted as Si / SiO2 / h-BN.

[0045] It should be noted that the Si / SiO2 substrate plays a supporting role in this step and needs to be ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes respectively before use, and then blown dry with dry nitrogen.

[0046] S2: epitaxial growth of organic semiconductor thin films;

[0047] Pentacene powder, used as a source of organic molecules, was placed in the center of the tube furnace;

[0048] The Si / SiO2 / h-BN substrate was placed in the downwind area of ​​the tube furnace, 9 to 11 cm away from the organic molecule source;

[0049] The parameters of the tube furnace were set as follows: evaporation source temperature of 160°C, vacuum degree of 200 Pa, growth time of 30 min, and carrier gas flow rate of 80 sccm. After the tube furnace temperature naturally cooled to room temperature, the sample was removed to form an ultrathin Pentacene single crystal film on the surface of the Si / SiO2 / h-BN substrate.

[0050] It should be noted that in this step, due to the van der Waals force between the organic molecules and the two-dimensional h-BN, the Pentacene molecules can be regularly arranged on the h-BN surface to form an ultra-thin Pentacene single crystal film.

[0051] S3: Transferring a single layer of transition metal disulfide film to the surface of the Pentacene single crystal film to form a heterojunction;

[0052] By mechanically exfoliating a single-layer MoS2 film as an inorganic layer, a heterostructure is formed with the organic layer of a Pentacene single crystal film;

[0053] It should be noted that in this step, the single-layer MoS2 can form a type II band structure with the ultra-thin Pentacene single crystal film. Only the type II band structure can form the token for exciton device communication - interlayer excitons;

[0054] Furthermore, since the lattice parameters of the single-layer MoS2 film and the ultra-thin Pentacene single crystal film are quite different and cannot form a moiré superlattice, there is no need to consider lattice alignment when transferring with the help of a two-dimensional material transfer platform, which greatly simplifies the preparation of room-temperature exciton switches.

[0055] It should be noted that the two layers of purely inorganic materials need to meet a certain angle when constructing exciton devices, and the inorganic two-dimensional materials also need to find the crystal axis before transfer, which greatly increases the difficulty of transfer.

[0056] S4: Transferring dielectric layer films to encapsulate heterojunctions.

[0057] The h-BN film with a thickness of 5 to 10 nm is mechanically peeled off and transferred to the heterostructure obtained in step S3 with the help of a two-dimensional material transfer platform for device packaging.

[0058] It should be noted that since exciton-based devices control switching by applying a vertical electric field to regulate the energy of interlayer excitons, there is no need to directly inject electrons (holes) into the semiconductor material.

[0059] S5: Transferring silver micrometer wire electrodes to the above structure to serve as gate electrodes.

[0060] Use a pipette to measure 5 μL of the Ag microwire solution and drop it onto the PDMS membrane used for assisted transfer. Under a microscope, find the silver microwires longer than 150 μm and mark them.

[0061] Using a two-dimensional material transfer platform, a silver microwire with a length greater than 150 μm is transferred to the top of the structure encapsulated in step S4 and used as a gate to obtain an organic / inorganic room temperature exciton switching device. Figure 2 As shown, Figure 2 In the figure, 1 represents Si / SiO2 substrate, 2 represents h-BN (thickness 5-10 nm), 3 represents Pentacene crystal film, 4 represents single-layer MoS2 film, 5 represents h-BN (thickness 5-10 nm), 6 represents Ag microwire, 7 represents light input end (source), and 8 represents light output end (drain).

[0062] Example 2

[0063] Referring to Example 1, this embodiment provides a method for preparing an organic / inorganic room-temperature exciton switch, specifically:

[0064] S1: Mechanically peel off a 10 nm thick h-BN film and transfer it to a Si / SiO2 substrate using a two-dimensional material transfer platform, denoted as Si / SiO2 / h-BN;

[0065] S2: Weigh 1 mg of Pentacene powder as an organic molecule source and place it in the center of the tube furnace;

[0066] A Si / SiO2 / h-BN substrate was placed in the downwind area of ​​a tube furnace, 11 cm away from an organic molecule source. The tube furnace parameters were set as follows: evaporation source temperature of 160°C, vacuum of 200 Pa, growth time of 30 minutes, and carrier gas flow rate of 80 sccm. After the tube furnace temperature naturally cooled to room temperature, the sample was removed, thereby forming an ultrathin Pentacene single crystal film on the surface of the Si / SiO2 / h-BN substrate.

[0067] S3: Mechanically exfoliate a single-layer MoS2 film as an inorganic layer, and transfer the single-layer MoS2 film to the surface of a Pentacene single-crystal film to form a heterostructure with the organic layer of the Pentacene single-crystal film;

[0068] S4: Mechanically peel off the 5 nm thick h-BN film and transfer it to the heterostructure obtained in step S3 with the help of a two-dimensional material transfer platform for device packaging.

[0069] S5: Use a pipette to measure 5 μL of the Ag microwire solution and drop it onto the PDMS membrane used for assisted transfer. Under a microscope, find the silver microwires longer than 150 μm and mark them.

[0070] A silver microwire larger than 150 μm is transferred to the top of the structure packaged in step S4 using a two-dimensional material transfer platform and used as a gate, thereby obtaining an organic / inorganic room-temperature exciton switching device.

[0071] In the absence of an external field, excitons diffuse out of the pump region (source) due to temperature and concentration gradients and reach the recombination site (drain), e.g. Figure 3 For the “on” state of the exciton switch, the diffusion distance is measured to be about 9 μm. On the contrary, by introducing a potential barrier (Vg = -14 V, Figure 4 ), the movement of excitons is hindered, thereby suppressing luminescence ("off" state).

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 2 is that the single-layer MoS2 film in step S3 is replaced by a double-layer MoS2 film. Specifically:

[0074] S1: Mechanically peel off a 10 nm thick h-BN film and transfer it to a Si / SiO2 substrate using a two-dimensional material transfer platform, denoted as Si / SiO2 / h-BN;

[0075] S2: Weigh 1 mg of Pentacene powder as an organic molecule source and place it in the center of a tube furnace. Place a Si / SiO2 / h-BN substrate in the downwind area of ​​the tube furnace, 11 cm away from the organic molecule source. Set the tube furnace parameters: evaporation source temperature of 160°C, vacuum degree of 200 Pa, growth time of 30 minutes, carrier gas flow rate of 80 sccm. After the tube furnace temperature naturally cools to room temperature, remove the sample, and an ultrathin Pentacene single crystal film is formed on the surface of the Si / SiO2 / h-BN substrate.

[0076] S3: Mechanically exfoliate a double-layer MoS2 film as an inorganic layer and transfer the double-layer MoS2 film to the surface of a Pentacene single crystal film to form a heterostructure with the organic layer of the Pentacene single crystal film;

[0077] S4: Mechanically peel off the 5 nm thick h-BN film and transfer it to the heterostructure obtained in step S3 with the help of a two-dimensional material transfer platform for device packaging.

[0078] S5: Use a pipette to measure 5 μL of Ag microwire solution and drop it on the PDMS film used to assist transfer, and find the silver microwires with a length greater than 150 μm under a microscope and mark them; use the two-dimensional material transfer platform to transfer a silver microwire greater than 150 μm to the top of the structure encapsulated in step S4, and use it as a gate to obtain the organic / inorganic room temperature exciton switching device of this comparative example.

[0079] Figure 5 This is the "on" state of the exciton switch corresponding to this comparative example. It can be seen that after replacing the single-layer MoS2 with a double-layer MoS2 film, no interlayer excitons are generated, so the diffusion of excitons cannot be observed. This means that even if other conditions are the same, an exciton device cannot be obtained.

[0080] Comparative Example 2

[0081] This comparative example cites the document "Room-temperature electrical control of exciton flux in a vanadium heterostructure". The study used MoS2 and WSe2 to form a heterostructure to build an exciton device. The diffusion distance of the device was only 5 μm. The exciton diffusion distance of the device of the present application is longer than that of the device.

[0082] In summary, the preparation method of the organic / inorganic room-temperature exciton switch of the present invention selects an organic semiconductor film with large exciton binding energy and a single-layer transition metal disulfide film to construct a heterojunction, without the need for lattice alignment, which simplifies the preparation of the room-temperature exciton switch, reduces the process cost, is beneficial to the application of device preparation, and realizes exciton switching at room temperature.

[0083] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An organic / inorganic room-temperature exciton switch, characterized in that: Using a single-layer MoS2 film as the inorganic layer and a Pentacene single-crystal film as the organic layer, the inorganic and organic layers form a heterostructure, which does not require lattice alignment to achieve exciton switching at room temperature.

2. The organic / inorganic room temperature exciton switch according to claim 1, wherein: The structure of the exciton switch from bottom to top includes: A substrate layer (1), made of Si / SiO2; The dielectric layer (2) is made of h-BN thin film with a thickness of 5 to 10 nm; The organic layer (3) is made of a Pentacene single crystal thin film; Inorganic layer (4), the material is a single layer MoS2 thin film; The encapsulation layer (5) is made of h-BN thin film with a thickness of 5 to 10 nm; Gate layer (6), made of Ag micron wire, with a length of >150nm; The light input end (7) and the light output end (8) are respectively located on both sides of the gate layer (6).

3. The method for preparing an organic / inorganic room-temperature exciton switch according to any one of claims 1 or 2, characterized in that: include, Mechanically peeling off an h-BN film with a thickness of 5 to 10 nm, and transferring it onto a pre-treated substrate layer (1) by means of a two-dimensional material transfer platform to form a dielectric layer (2) to obtain Si / SiO2 / h-BN; Pentacene powder is used as an organic molecule source and placed in the center of a tube furnace. Si / SiO2 / h-BN is placed in the downwind area of ​​the tube furnace and evaporated to form a Pentacene single crystal film, which is the organic layer (3). A single-layer MoS2 film is mechanically peeled off as an inorganic layer (4) to form a heterojunction structure with the organic layer (3); Mechanically peeling off an h-BN film with a thickness of 5 to 10 nm, and transferring it to the surface of the formed heterojunction structure by means of a two-dimensional material transfer platform to form an encapsulation layer (5); Silver microwires are transferred to the top of the encapsulation layer (5) with the aid of a two-dimensional material transfer platform to form a gate layer (6), and a light input end (7) and a light output end (8) are respectively provided on both sides of the gate layer (6), thereby obtaining an organic / inorganic room temperature exciton switch.

4. The method for preparing an organic / inorganic room-temperature exciton switch according to claim 3, wherein: The substrate layer is made of Si / SiO2, and its pretreatment includes ultrasonic cleaning with acetone, ethanol, and deionized water for 10 to 15 minutes respectively, and drying with dry nitrogen.

5. The method for preparing an organic / inorganic room temperature exciton switch according to claim 3, wherein: The evaporation source temperature of the tube furnace is 160-180° C., the vacuum degree is 100-200 Pa, and the carrier gas flow rate is 60-80 sccm.

6. The method for preparing an organic / inorganic room temperature exciton switch according to claim 5, wherein: The growth time of the evaporation growth is 30 to 40 minutes.

7. The method for preparing an organic / inorganic room-temperature exciton switch according to claim 3, wherein: The distance between the Si / SiO2 / h-BN and the organic molecule source is 9 to 11 cm.

8. The method for preparing an organic / inorganic room-temperature exciton switch according to claim 3, wherein: The length of the silver microwire is greater than 150 μm.

9. Use of an exciton switch prepared by the preparation method according to any one of claims 1 to 8 in directly processing optical data streams.

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