A single photon source based on an upconversion optoelectronic device and a preparation method thereof

Abstract

The present invention relates to the field of molecular optoelectronic devices, and provides a single photon source based on an upconversion optoelectronic device and a preparation method thereof. The preparation method includes: preparing a dielectric layer; preparing a graphene array electrode on the dielectric layer; constructing a graphene nano-gap point electrode pair; placing the graphene nano-gap point electrode pair in a two-neck flask, adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and a part of the upconversion luminescent molecule A to the two-neck flask, and adding anhydrous pyridine to the two-neck flask under a nitrogen environment to obtain a device with a part of the upconversion luminescent molecule A connected at both ends, and putting it into a tetrahydrofuran solution together with a part of the upconversion luminescent molecule B containing a lanthanide metal for molecular system chelation to obtain a single-molecule upconversion optoelectronic device containing a chiral group; plating a liquid metal Ga2O3 protective layer on the single-molecule upconversion optoelectronic device to obtain a single photon source, enhancing the stability and anti-interference ability of the single photon source.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular optoelectronic devices, and particularly to a single photon source based on an upconversion optoelectronic device and a preparation method thereof. Background Technique

[0002] Quantum information technology is an emerging interdisciplinary subject. The core of this technology lies in utilizing quantum state characteristics such as quantum superposition and quantum entanglement to achieve efficient storage, processing, and transmission of information, thereby exceeding traditional information technology in terms of computing power, information security, and sensing measurement accuracy. Photons, as ideal physical carriers in quantum information technology, have characteristics such as strong anti-interference ability, long decoherence time, and rich degrees of freedom. These characteristics of photons enable them to exhibit great application potential in fields such as quantum communication, quantum computing, and quantum measurement. To further realize the application of quantum photonics, three technologies are required as supports, including photon counters, linear and nonlinear photon circuits, and single photon sources. These technologies are the core components for constructing quantum communication and quantum computing systems. In recent years, undoubtedly great progress has been made in photon counters and photon circuits, but the lack of single photon sources undoubtedly hinders the further development of quantum technology. A single photon source is the basic resource for realizing quantum communication and quantum computing, and its performance directly affects the security and efficiency of communication. The generation of single photons is the primary condition for single photon communication and is also one of the current research hotspots in quantum secure communication.

[0003] A single photon source refers to a light source that can generate single photons, characterized by emitting only one photon each time and the emission being deterministic. Therefore, it is also called anti-bunching. The preparation of a highly efficient, stable, reliable, and easily obtainable single photon source is one of the bottlenecks restricting the development of related technologies. To achieve a single photon source that can be used in quantum communication, it is required to have characteristics such as high emission efficiency, controllable emission wavelength, high purity, high full identity, high deterministic polarization, and high efficiency. Meeting these characteristics poses a huge challenge to the research of optical quantum technology. Currently, most common single photon sources are based on spontaneous emission or regulation of quantum dots, diamond color centers, etc. However, due to their own limitations such as charge, their applications in quantum technology are restricted. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the related technologies. For this purpose, the present invention provides a single photon source based on an upconversion optoelectronic device and a preparation method thereof, enhancing the stability and anti-interference ability of the single photon source.

[0005] The present invention provides a single photon source based on an upconversion optoelectronic device and a preparation method thereof, including:

[0006] S1: Prepare a dielectric layer;

[0007] S2: Prepare a graphene array electrode on the dielectric layer;

[0008] S3: Based on the graphene array electrode, construct a pair of graphene nano-gap point electrodes;

[0009] S4: Place the pair of graphene nano-gap point electrodes in a two-neck flask, add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and the A part of the upconversion luminescent molecule to the two-neck flask, and add anhydrous pyridine to the two-neck flask under a nitrogen environment to obtain a device with the A part of the upconversion luminescent molecule connected at both ends;

[0010] S5: Under an anhydrous and anaerobic environment, put the device with the A part of the upconversion luminescent molecule connected at both ends and the B part of the upconversion luminescent molecule containing lanthanide metal into a tetrahydrofuran solution for molecular system chelation to obtain a single-molecule upconversion optoelectronic device containing a chiral group;

[0011] S6: Deposit a layer of liquid metal Ga 2 O 3 protective layer on the single-molecule upconversion optoelectronic device containing a chiral group to obtain a single-photon source.

[0012] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S1 includes the following steps:

[0013] S11: Spin-coat a photoresist on a pure silicon wafer, obtain a first negative film by photolithographing the external lead electrode of the gate, evaporate chromium and gold electrodes on the first negative film to obtain a second negative film, and immerse the second negative film in an acetone solution for degumming to obtain a third negative film;

[0014] S12: Spin-coat a photoresist on the third negative film, perform ultraviolet photolithography on the gate electrode to obtain a bottom gate;

[0015] S13: Deposit an aluminum film on the surface of the bottom gate by thermal evaporation, then place the bottom gate in an acetone solution for degumming, and obtain a dielectric layer of aluminum oxide by natural oxidation;

[0016] S14: Deposit a hafnium oxide film on the surface of the dielectric layer of aluminum oxide by atomic beam deposition technology to obtain a dielectric layer.

[0017] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, evaporate 6-8 nm of chromium and 30-40 nm of gold electrodes on the first negative film; deposit 30-40 nm of aluminum film on the surface of the bottom gate; deposit 3-10 nm of hafnium oxide film on the surface of the dielectric layer of aluminum oxide.

[0018] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S2 includes the following steps:

[0019] S21: Perform chemical vapor deposition on a copper sheet to obtain single-layer graphene. Stick the copper sheet with single-layer graphene on a glass sheet using tape, spin-coat polymethyl methacrylate (PMMA), etch the back of the copper sheet using oxygen plasma, soak the copper sheet with single-layer graphene in a ferric chloride solution, remove the copper sheet at the bottom of the graphene, soak it in hydrochloric acid solution and ultrapure water solution respectively, and then remove the surface PMMA to obtain a graphene electrode;

[0020] S22: Photolithograph stripes on the graphene electrode, and expose the stripes with ultraviolet light. Use a developer to remove the photoresist outside the stripes, and then perform oxygen plasma etching to obtain a silicon wafer with graphene stripes;

[0021] S23: Expose the silicon wafer with graphene stripes with ultraviolet light, and deposit a magnetic material on one side of the silicon wafer with graphene stripes using magnetron sputtering technology to obtain a silicon wafer with a magnetic electrode;

[0022] S24: Expose the silicon wafer with a magnetic electrode with ultraviolet light, and evaporate chromium and gold electrodes on the other side of the silicon wafer with graphene stripes to obtain a graphene array electrode.

[0023] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, deposit 8 - 10 nm of chromium and 70 nm of magnetic material on one side of the silicon wafer with graphene stripes;

[0024] Evaporate 8 - 10 nm of chromium and 60 - 80 nm of gold electrodes on the other side of the silicon wafer with graphene stripes.

[0025] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S3 includes the following steps:

[0026] S31: Use electron beam exposure to etch on the graphene array electrode, and then develop it with a developer to obtain a graphene array electrode with dotted lines;

[0027] S32: Use oxygen plasma to etch the graphene array electrode with dotted lines, and then use a semiconductor parameter analyzer and a room temperature probe station to perform real-time on-off tests on the graphene array electrode to obtain a graphene nanogap point electrode pair.

[0028] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, the dotted lines on the graphene array electrode with dotted lines are 150 nm in length and 5 nm in width.

[0029] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S4 includes the following steps:

[0030] After sealing the two-necked flask, perform repeated evacuation and gas replacement operations to make the two-necked flask in a nitrogen environment. Use a syringe to extract 10 ml of anhydrous pyridine and inject it into the two-necked flask under nitrogen environment, and react for more than 48 h to obtain a device with upconversion luminescent molecule A parts connected at both ends.

[0031] According to a single photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, the single molecule upconversion luminescent molecule in the single molecule upconversion optoelectronic device containing a chiral group includes an upconversion luminescent molecule A part and an upconversion luminescent molecule B part. The connection mode of the upconversion luminescent molecule A part and the upconversion luminescent molecule B part is of the A-B-A type, and the structure of the upconversion luminescent molecule A part is as follows:

[0032]

[0033] Among them, the upconversion luminescent molecule B part includes XCl 3 (THF) 3 , X includes one of the lanthanide metals Tm, Yb, and Er. The molecular formula of the single molecule upconversion luminescent molecule containing a chiral group after assembly includes:

[0034] ,

[0035] or

[0036] one of them.

[0037] According to a single photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, the molar ratio of the upconversion luminescent molecule A part to 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is 1:20 to 1:40.

[0038] One or more of the above technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0039] According to the single photon source based on an upconversion optoelectronic device and a preparation method thereof in the embodiments of the present invention, by designing a single molecule upconversion optoelectronic device containing a chiral group, the problem of restricting the preparation of a single photon source is solved, the ability to increase the circularly polarized luminescence of the single photon source is realized, and further the certainty of the single photon polarization emitted by the single photon source is enhanced, so that the photon has a stronger anti-stray interference ability and improves the identity of the photon; at the same time, due to the strong anti-photobleaching property of the upconversion luminescent molecule in the upconversion optoelectronic device, the stability and continuity of the single photon source luminescence are improved, and the development of quantum information technology is promoted.

[0040] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0042] Figure 1 FIG. is a schematic structural diagram of a single photon source prepared by the single photon source based on an upconversion optoelectronic device and its preparation method provided by the present invention.

[0043] Figure 2 FIG. is a topographic diagram of the torn graphene of the single photon source based on an upconversion optoelectronic device and its preparation method provided by the present invention.

[0044] Figure 3 FIG. is a luminescence diagram of the single photon source prepared by the single photon source based on an upconversion optoelectronic device and its preparation method provided by the present invention.

[0045] Figure 4 FIG. is a characteristic diagram of the current varying with the gate voltage of the single-molecule upconversion optoelectronic device of the single photon source based on an upconversion optoelectronic device and its preparation method provided by the present invention when the bias voltage is 0.2V.

[0046] Figure 5 FIG. is a characteristic diagram of the current varying with the gate voltage of the single-molecule upconversion optoelectronic device of the single photon source based on an upconversion optoelectronic device and its preparation method provided by the present invention when the bias voltage is -0.2V.

[0047] Reference Signs:

[0048] 1. Graphene nanogap point electrode pair; 2. Gold electrode; 3. Liquid metal Ga 2 O 3 Protective layer; 4. Magnetic electrode; 5. Silicon wafer; 6. Upconversion luminescent molecule. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0050] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0051] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0052] Upconversion luminescence mainly involves several key nonlinear optical processes, mainly including excited state absorption, energy transfer upconversion, photon avalanche, etc., which enable the material to convert photons with lower energy into photons with higher energy, and it is a good luminescent material. The present invention constructs a single photon source based on a single molecule upconversion optoelectronic device, selects a single upconversion luminescent molecule as the functional molecule and connects it to the graphene array electrode with a nanogap, which can ensure the generation of a single photon. Utilizing the luminescence characteristics of the upconversion luminescent molecule itself, by applying a specific low-energy light source or a small bias voltage and gate voltage for regulation, the stable emission of a single high-energy photon is achieved.

[0053] Since the designed upconversion luminescent molecule has a chiral group, this not only enhances the circularly polarized luminescence characteristics of the single photon source, but also further improves the circularly polarized luminescence performance of the single photon source by introducing a spin current through constructing a magnetic electrode. At the same time, the identity of the photons emitted by the single photon source is improved, enabling the realization of circularly polarized single photon emission with high purity, high quality, high stability, and high continuity, providing strong support for fields such as optical quantum information processing and quantum communication.

[0054] Figure 1 It is a schematic structural diagram of a single photon source prepared by the single photon source and its preparation method based on an upconversion optoelectronic device provided by the present invention.

[0055] The present invention provides a single photon source based on an upconversion optoelectronic device and its preparation method, asFigure 1 As shown in Figure 1 , a single-photon source based on an upconversion optoelectronic device and its preparation method include:

[0056] S1: Prepare a dielectric layer;

[0057] S2: Prepare a graphene array electrode on the dielectric layer;

[0058] S3: Based on the graphene array electrode, construct a graphene nano-gap point electrode pair 1;

[0059] S4: Place the graphene nano-gap point electrode pair 1 in a two-necked flask, add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and part A of the upconversion luminescent molecule to the two-necked flask, and add anhydrous pyridine to the two-necked flask under a nitrogen environment to obtain a device with part A of the upconversion luminescent molecule connected at both ends;

[0060] S5: Under an anhydrous and anaerobic environment, place the device with part A of the upconversion luminescent molecule connected at both ends and part B of the upconversion luminescent molecule containing a lanthanide metal in a tetrahydrofuran solution for molecular system chelation to obtain a single-molecule upconversion optoelectronic device containing a chiral group;

[0061] S6: Deposit a layer of liquid metal Ga 2 O 3 protective layer 3 on the single-molecule upconversion optoelectronic device containing a chiral group to obtain a single-photon source.

[0062] In this embodiment, by designing a single-molecule upconversion optoelectronic device containing a chiral group, the problem of restricting the preparation of a single-photon source is solved, the ability to increase the circularly polarized luminescence of the single-photon source is realized, and further the certainty of the single-photon polarization emitted by the single-photon source is enhanced, so that the photon has a stronger anti-stray interference ability and the photon identity is improved; at the same time, due to the strong anti-photobleaching property of the upconversion luminescent molecule 6 in the upconversion optoelectronic device, the stability and continuity of the single-photon source luminescence are improved, promoting the development of quantum information technology.

[0063] According to some embodiments of the present invention, take out the prepared single-molecule upconversion optoelectronic device from the two-necked flask, wash it three times with acetone and ultrapure water respectively, and finally dry the surface with nitrogen for standby.

[0064] According to some embodiments of the present invention, deposit a layer of liquid metal Ga 2 O 3 with a thickness of 1-20 nm on the surface of the single-molecule upconversion optoelectronic device as a protective layer. Preferably, the thickness of the liquid metal Ga 2 O 3 protective layer 3 is 15 nm.

[0065] A single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S1 includes the following steps:

[0066] S11: Spin-coat photoresist on a pure silicon wafer 5, obtain a first negative film by lithographing the external lead electrodes of the gate, evaporate chromium and gold electrodes 2 on the first negative film to obtain a second negative film, and immerse the second negative film in an acetone solution for degumming to obtain a third negative film;

[0067] S12: Spin-coat photoresist on the third negative film, perform ultraviolet lithography on the gate electrode to obtain a bottom gate;

[0068] S13: Deposit an aluminum film on the surface of the bottom gate by thermal evaporation, then place the bottom gate in an acetone solution for degumming, and obtain a dielectric layer of aluminum oxide through natural oxidation;

[0069] S14: Deposit a hafnium oxide film on the surface of the dielectric layer of aluminum oxide by atomic beam deposition technology to obtain a dielectric layer.

[0070] According to some embodiments of the present invention, the surface of the pure silicon wafer is covered with silicon oxide of 300 - 400 nm. Preferably, the thickness of the silicon oxide is 350 nm.

[0071] According to some embodiments of the present invention, the external lead electrodes of the gate lithographed on the first negative film are used for subsequent probe testing and calibration of subsequent lithography.

[0072] According to some embodiments of the present invention, the bottom gate needs to be connected to the evaporated metal.

[0073] According to some embodiments of the present invention, an aluminum film is deposited on the surface by thermal evaporation as a gate electrode for applying a gate voltage. After degumming with acetone, a dielectric layer of aluminum oxide is obtained through natural oxidation.

[0074] A single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, evaporate 6 - 8 nm of chromium and 30 - 40 nm of gold electrodes 2 on the first negative film; deposit 30 - 40 nm of an aluminum film on the surface of the bottom gate; deposit 3 - 10 nm of a hafnium oxide film on the surface of the dielectric layer of aluminum oxide.

[0075] According to some preferred embodiments of the present invention, evaporate 7 nm of chromium and 35 nm of gold electrodes 2 on the first negative film; deposit 35 nm of an aluminum film on the surface of the bottom gate; deposit 6 nm of a hafnium oxide film on the surface of the dielectric layer of aluminum oxide.

[0076] A single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S2 includes the following steps:

[0077] S21: performing chemical vapor deposition on a copper sheet to obtain a single-layer graphene, adhering the copper sheet containing the single-layer graphene to a glass sheet with an adhesive tape, spin-coating polymethyl methacrylate (PMMA), etching the back of the copper sheet using oxygen plasma, soaking the copper sheet containing the single-layer graphene in a ferric chloride solution, removing the copper sheet at the bottom of the graphene, respectively soaking in a hydrochloric acid solution and an ultrapure water solution, and then removing the surface PMMA to obtain a graphene electrode;

[0078] According to some embodiments of the present invention, a single layer of graphene is obtained on a copper sheet by chemical vapor deposition (CVD) technology, the copper sheet is adhered to a dielectric layer using transparent glue, polymethyl methacrylate (PMMA 950) is spin-coated on the surface of the copper sheet, first at a speed of 600 revolutions per minute for 6 seconds for pre-smoothing treatment, and then at a speed of 4000 revolutions per minute for 40 seconds for smoothing treatment. After the glue is spread, the PMMA glue is dried by heating at 180 degrees Celsius for two minutes on a heating table, and the excess graphene on the back of the copper sheet is etched using an oxygen plasma machine (Reaction Ion Etching, RIE). The resulting copper sheet is cut into 1cm×1cm squares, and the copper sheet is placed face up in a ferric chloride solution for a period of time, and then immersed in a hydrochloric acid solution, an aqueous solution, a potassium hydroxide solution, and an aqueous solution for multiple cycles to remove the ferric chloride and impurities. Finally, the graphene layer is transferred to the dielectric layer, and the glue is removed by heating at 120°C with a boiling acetone solution for 8 minutes to obtain a graphene electrode.

[0079] Figure 2 It is a morphology diagram of hand-torn graphene of a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention.

[0080] According to other embodiments of the present invention, a hand-torn graphene method is selected to obtain a graphene electrode, and the specific operating steps are as follows: stick a layer of graphene on the graphite with tape, let it stand for 4 to 5 hours, peel off the tape, and obtain the graphene electrode by screening. The time for peeling off the tape can also be shortened by heating at 110°C for 2 minutes.

[0081] According to some embodiments of the present invention, a microscope is used to screen graphene. If the graphene is blue or purple, such as Figure 2 As shown ( Figure 2 (circled in the box) indicates that the number of graphene layers is 2 to 4, which can be used as a graphene electrode.

[0082] S22: photolithographically forming strips on the graphene electrode, exposing the strips to ultraviolet light, removing the photoresist outside the strips using a developer, and then performing oxygen plasma etching to obtain a silicon wafer having graphene strips;

[0083] According to some embodiments of the present invention, a strip with a width of 40 μm and a length of 200 μm is lithographed on the graphene electrode using an ultraviolet photoresist. The strip is exposed by ultraviolet lithography, where the part of the strip to be retained is protected with photoresist, and the rest is removed by a developer, exposing the graphene layer under the photoresist. The exposed graphene layer is etched by oxygen plasma RIE. After the etching is completed, the remaining photoresist is removed with acetone to obtain a silicon wafer with graphene strips.

[0084] S23: The silicon wafer with graphene strips is exposed by ultraviolet light, and a magnetic material is deposited on one side of the silicon wafer with graphene strips using magnetron sputtering technology to obtain a silicon wafer with a magnetic electrode 4;

[0085] According to some embodiments of the present invention, as Figure 1 shown, an ultraviolet photoresist is spin-coated on the silicon wafer with graphene strips, lithography of the electrode part is performed, developed after ultraviolet exposure, and after development, 8 - 10 nm of chromium and 70 nm of magnetic material are deposited on the silicon wafer with graphene strips using magnetron sputtering technology. The magnetic material includes any one of iron, cobalt, or nickel metals; finally, the excess metal and photoresist are removed with acetone to obtain a magnetic electrode 4. The magnetic electrode 4 realizes efficient spin-selective transmission, allowing only electrons with a specific spin direction to pass through. Therefore, a spin-polarized current is generated in the experiment, enabling the silicon wafer with the magnetic electrode 4 to emit circularly polarized photons, thereby improving the determinacy of single-photon polarization.

[0086] S24: The silicon wafer with the magnetic electrode 4 is exposed by ultraviolet light, and chromium and gold electrodes 2 are evaporated on the other side of the silicon wafer with graphene strips to obtain a graphene array electrode.

[0087] According to some embodiments of the present invention, an ultraviolet photoresist is spin-coated on the silicon wafer with the magnetic electrode 4, lithography of the other-side gold electrode 2 is performed, developed after ultraviolet exposure, and after development, 8 nm of chromium and 80 nm of gold are evaporated on the silicon wafer with the magnetic electrode 4 as the other-end electrode using thermal evaporation. Finally, the excess metal and photoresist are removed with acetone to obtain a gold electrode 2, as Figure 1 shown, and finally a graphene array electrode is obtained. The part between the magnetic electrode 4 and the gold electrode 2 is called a graphene channel, as Figure 1 shown.

[0088] According to some embodiments of the present invention, the conductivity of the graphene array electrode is tested and screened. The conductivity of the graphene array electrode is tested using an SM-6 probe station at a voltage of 50 mV. The graphene array electrode with a conductivity in the order of 10 μA can be used to prepare a graphene nano-gap point electrode pair 1.

[0089] According to a single photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, 8-10 nm of chromium and 70 nm of a magnetic material are plated on one side of the silicon wafer with graphene strips;

[0090] On the other side of the silicon wafer with graphene strips, 8-10 nm of chromium and 60-80 nm of a gold electrode 2 are evaporated.

[0091] According to a single photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S3 includes the following steps:

[0092] S31: Use electron beam lithography to etch on the graphene array electrode, and then develop with a developer to obtain a graphene array electrode containing dotted lines;

[0093] According to some embodiments of the present invention, PMMA is spin-coated on the graphene array electrode, and an electron beam is used to etch dotted lines with a length of 150 nm and a width of 5 nm in each graphene channel. Methyl isobutyl ketone (MIBK) diluted with isopropyl alcohol is used, and the volume ratio of MIBK to isopropyl alcohol is MIBK / isopropyl alcohol = 1 / 3. The methyl isobutyl ketone solution diluted with isopropyl alcohol is used for development to obtain a graphene array electrode containing dotted lines, that is, a graphene dot electrode.

[0094] S32: Use oxygen plasma to etch the graphene array electrode containing dotted lines, and then use a semiconductor parameter analyzer and a room temperature probe station to perform real-time on-off tests on the graphene array electrode to obtain a graphene nanogap point electrode pair 1.

[0095] According to some embodiments of the present invention, the nanogap of the graphene nanogap point electrode pair 1 is 1-10 nm.

[0096] According to a single photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, the dotted lines on the graphene array electrode containing dotted lines have a length of 150 nm and a width of 5 nm.

[0097] According to a single photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, S4 includes the following steps:

[0098] Seal the two-necked flask and perform repeated evacuation and gas replacement operations to make the two-necked flask in a nitrogen environment. Use a syringe to draw 10 ml of anhydrous pyridine and inject it into the two-necked flask in the nitrogen environment, and react for more than 48 h to obtain a device with an upconversion luminescent molecule A part connected at both ends.

[0099] Figure 3 It is the luminescence diagram of the single photon source prepared by the single photon source based on the upconversion optoelectronic device and the preparation method thereof provided by the present invention. Figure 4It is the characteristic diagram of the current varying with the gate voltage when the bias voltage is 0.2 V for the single-molecule upconversion optoelectronic device of the single-photon source based on upconversion optoelectronic devices and its preparation method provided by the present invention. Figure 5 It is the characteristic diagram of the current varying with the gate voltage when the bias voltage is -0.2 V for the single-molecule upconversion optoelectronic device of the single-photon source based on upconversion optoelectronic devices and its preparation method provided by the present invention.

[0100] According to a single-photon source based on upconversion optoelectronic devices and its preparation method provided by the present invention, the single-molecule upconversion luminescent molecule 6 in the single-molecule upconversion optoelectronic device containing a chiral group includes an upconversion luminescent molecule A part and an upconversion luminescent molecule B part, and the connection mode of the upconversion luminescent molecule A part and the upconversion luminescent molecule B part is of the A-B-A type, wherein the structure of the upconversion luminescent molecule A part is as follows:

[0101]

[0102] Among them, the upconversion luminescent molecule B part includes XCl 3 (THF) 3 , X includes one of the lanthanide metals Tm, Yb, and Er. The molecular formula of the single-molecule upconversion luminescent molecule 6 containing a chiral group after assembly includes:

[0103] ,

[0104] or

[0105] one of them.

[0106] According to some embodiments of the present invention, the specific synthesis route of the upconversion luminescent molecule A part is as follows:

[0107]

[0108] Under an anhydrous and oxygen-free nitrogen atmosphere, 2 mmol , 6 mmol trimethylsilylacetylene, 0.04 mmol Pd(PPh 3 ) 4 and 0.04 mmol CuI and 250 ml triethylamine are successively added to a two-necked flask. React at 90 °C for 1 day under a nitrogen environment. After cooling, pour the reactants into water and extract three times with dichloromethane (100 ml), and remove the excess solvent by filtration. Dissolve the obtained solid in ethanol, add 20 ml K 2 CO 3 , and react at room temperature for 1 day. Remove the excess ethanol by filtration, wash the solid with dichloromethane, spin-dry the obtained solution, and then purify the product by column chromatography to obtain .

[0109]

[0110] Under an anhydrous and anaerobic nitrogen atmosphere, 2 mmol , 1.8 mmol , 0.04 mmol Pd(PPh 3 ), 4 and 10 ml of an aqueous solution of K 2 CO 3 (20 mmol) and 250 ml of toluene were successively added to a two-necked flask. The mixture was refluxed for 1 day under a nitrogen atmosphere. After cooling, the reaction mixture was poured into water and extracted three times with dichloromethane (100 ml). The excess solvent was removed by filtration, and then the product was purified by column chromatography and obtained by chiral separation .

[0111]

[0112] Under an anhydrous and anaerobic nitrogen atmosphere, 1.5 mmol , 2 mmol , 0.04 mmol Pd(PPh 3 ), 4 and 10 ml of an aqueous solution of K 2 CO 3 (20 mmol) and 250 ml of toluene were successively added to a two-necked flask. The mixture was refluxed for 1 day under a nitrogen atmosphere. After cooling, the reaction mixture was poured into water and extracted three times with dichloromethane (100 ml). The excess solvent was removed by filtration, and then the product was purified by column chromatography to obtain .

[0113]

[0114] Under an anhydrous and anaerobic nitrogen atmosphere, 1.5 mmol , 2 mmol , 0.04 mmol Pd(PPh 3 ), 4 and 10 ml of an aqueous solution of K 2 CO 3 (20 mmol) and 250 ml of toluene were successively added to a two-necked flask. The mixture was refluxed for 1 day under a nitrogen atmosphere. After cooling, the reaction mixture was poured into water and extracted three times with dichloromethane (100 ml). The excess solvent was removed by filtration, and then the product was purified by column chromatography to obtain .

[0115]

[0116] Under an anhydrous and oxygen-free nitrogen atmosphere, 1.5 mmol was successively added to a two-necked flask , 2 mmol , 0.04 mmol Pd(PPh 3 ), 4 and 10 ml of an aqueous solution of K 2 CO 3 (20 mmol), as well as 250 ml of toluene. It was refluxed for 1 day under nitrogen. After cooling, the reaction mixture was poured into water and extracted three times with dichloromethane (100 ml). The excess solvent was removed by filtration, and then the product was purified by column chromatography to obtain .

[0117] Under an anhydrous and oxygen-free nitrogen atmosphere, 0.3 mmol and an excess of CF 3 COOH, as well as 100 ml of dichloromethane, were added successively to a two-necked flask. The reaction was carried out for 1 day under a nitrogen atmosphere. After cooling, the reaction mixture was poured into water and extracted three times with dichloromethane (100 ml). The excess solvent was removed by filtration, and then the product was purified by column chromatography to obtain .

[0118] According to some embodiments of the present invention, as Figure 1 shown, a silicon wafer was used as a substrate, a gold electrode 2 was evaporated on one side, a magnetic electrode 4 was prepared on the other side, a graphene nanogap point electrode pair 1 with a nanogap was prepared therebetween, a single upconversion luminescent molecule 6 was introduced by forming an amide bond, a single-molecule upconversion optoelectronic device was obtained, and a layer of liquid metal Ga 2 O 3 was prepared on its surface as a protective layer to obtain a single photon source.

[0119] According to some embodiments of the present invention, as Figure 3 shown, where the light spot (such as Figure 3The single photon emitted by the single photon source (as shown in the enlarged dashed box) has high purity and good stability. Since the functional molecule of the single-molecule upconversion optoelectronic device is a single upconversion luminescent molecule 6, which can emit only one photon at a time under a given excitation, photon generation can be achieved by means of light source excitation or electric field excitation. Since the upconversion luminescent molecule 6 can be regulated by an external electric field, by applying different gate voltages, the energy level distribution of electrons in the upconversion material can be changed, affecting the energy level transition of ions, so that the relative position between the frontier molecular orbital and the Fermi level of the electrode can be controllably changed, thereby realizing the emission of photons with different wavelengths. At the same time, at a specific gate voltage and bias voltage, electrons can be excited to a specific energy level, so as to ensure that the emitted single photons have high purity. At the same time, since the upconversion luminescent molecule 6 has chirality, it increases the ability of the single electron source to emit circularly polarized light, further enhancing the determinacy of the polarization of the single photon emitted by the single electron source, making the photon have stronger anti-stray interference ability, and also improving the identity of the photon.

[0120] According to some embodiments of the present invention, the spectral characteristics of the emitted photons can be regulated during the test. The test temperature can be adjusted in the range of 90~350K by using a TTPX cryogenic probe station, or a femtosecond laser can be introduced to apply a light source with a specific power and specific wavelength to the single-molecule upconversion optoelectronic device, or the spectral characteristics of the emitted single photons can be regulated by applying magnetic fields with different intensities using a comprehensive physical property measurement system PPMS. At the same time, taking advantage of the narrow-band emission characteristics of the upconversion luminescent molecule 6, the emitted photons generally have high spectral purity and narrow bandwidth, thereby further improving the purity and emission efficiency of the single photon source.

[0121] According to some embodiments of the present invention, taking a single upconversion luminescent molecule 6 as the functional molecule, first, the amino groups (-NH 2 ) at both ends of the A part of the single upconversion luminescent molecule are subjected to amide bonding with the carboxyl groups (-COOH) at the ends of the graphene nano-gap point electrode pair 1, and then the part of the single-molecule upconversion optoelectronic device containing the lanthanide metal upconversion luminescent molecule B is chelated, where the lanthanide metal includes any one of Tm, Yb, and Er, to construct a single photon source based on the single-molecule upconversion optoelectronic device. As Figure 4 and Figure 5 shown, at a certain bias voltage, the conductance changes with the change of the gate voltage, which not only indicates that the single upconversion luminescent molecule 6 is successfully connected to the graphene nano-gap point electrode pair 1, but also shows that the gate voltage can regulate it.

[0122] Among them, the upconversion luminescent molecule 6 is composed of lanthanide metals, and the upconversion luminescent molecule 6 has the following advantages:

[0123] (1) Emitting high-purity photons: Since the upconversion luminescent molecule 6 has the characteristics of narrow-band emission and a large Stokes shift, it helps to reduce background noise and improve the sensitivity of signal detection, emitting high-purity and high-quality photons.

[0124] (2) High conversion efficiency: The upconversion luminescent molecule 6 is excited by a lower-energy light source and can convert more absorbed light into high-energy photons. It can be excited with a smaller bias voltage, which reduces energy consumption to a certain extent and improves the efficiency of the single-photon source.

[0125] (3) High collection rate: Since the upconversion luminescent molecule 6 usually has a long luminescence lifetime, it is convenient for photon collection and analysis within a certain time range.

[0126] (4) High continuity: Since the upconversion luminescent molecule 6 has strong photobleaching, the process of emitting photons is stable and photons can be continuously emitted.

[0127] According to a single-photon source based on an upconversion optoelectronic device and a preparation method thereof provided by the present invention, the molar ratio of the A part of the upconversion luminescent molecule to 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride is 1:20 to 1:40.

[0128] A single-photon source based on an upconversion optoelectronic device and a preparation method thereof according to an embodiment of the present invention has the following technical effects compared with the prior art:

[0129] 1. Prepared based on a graphene-based single-molecule optoelectronic device, selecting a single upconversion luminescent molecule as the functional molecule can ensure the generation of single photons, and the upconversion luminescent molecule endows the single-photon source with characteristics such as high stability, long emission photon lifetime, and low-energy excitation.

[0130] 2. Taking a single upconversion luminescent molecule as the functional molecule, first, the amino groups (-NH 2 ) at both ends of the A part of the single upconversion luminescent molecule are subjected to amide bonding with the carboxyl groups (-COOH) at the ends of the graphene nano-gap point electrodes. Then, the single-molecule upconversion optoelectronic device is chelated with lanthanide metals to construct a single-photon source based on the single-molecule upconversion optoelectronic device. At the same time, based on the construction of the gate electrode and the electrical system, taking advantage of the characteristic that the upconversion luminescent molecule can convert lower-energy photons into higher-energy photons, the emission of single photons is regulated by applying external fields such as a light source, a smaller bias voltage, and a gate voltage, and the generation of single photons with controllable wavelengths can be realized, providing technical support for emitting high-purity, high-quality, and high-collection-rate single photons and laying a foundation for the further development of quantum information technology.

[0131] 3. By constructing magnetic electrodes, spin current is introduced to achieve the property of circularly polarized luminescence. At the same time, since the designed upconversion luminescent molecule has a chiral group, the ability of the single-photon source to emit circularly polarized light is increased, further enhancing the certainty of the polarization of the single photon emitted by the single-photon source, making the photon have a stronger ability to resist stray interference and also improving the indistinguishability of the photon. At the same time, due to the strong anti-photobleaching property of the upconversion luminescent molecule, the stability and continuity of the single-photon source luminescence are improved, promoting the development of quantum information technology.

[0132] 4. Using a single-molecule upconversion optoelectronic device as a carrier to achieve the emission of single photons, the device size is miniaturized, with strong scalability. Moreover, the prepared optoelectronic device has 300 conductive channels and strong integratability, providing a research basis for the research of multi-photon quantum computing and quantum communication.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a single photon source based on an upconversion optoelectronic device, characterized in that: include: S1: preparing a dielectric layer; S2: preparing a graphene array electrode on the dielectric layer; S3: Based on graphene array electrodes, graphene nanogap point electrode pairs are constructed; S4: placing the graphene nanogap point electrode pair in a two-necked flask, adding 1-(3-dimethylaminopropyl)-3-2-ethylcarbodiimide hydrochloride and the upconversion luminescent molecule A part into the two-necked flask, and adding anhydrous pyridine into the two-necked flask under a nitrogen environment to obtain a device with the upconversion luminescent molecule A part connected at both ends; S5: placing the device with the upconversion luminescent molecule A connected at both ends and the upconversion luminescent molecule B containing a lanthanide metal into a tetrahydrofuran solution in an anhydrous and oxygen-free environment to carry out molecular system chelation to obtain a single-molecule upconversion photoelectric device containing a chiral group; S6: coating a liquid metal Ga2O3 protective layer on the single-molecule up-conversion optoelectronic device containing a chiral group to obtain a single-photon source; The single-molecule up-conversion luminescent molecule in the single-molecule up-conversion photoelectric device containing a chiral group comprises an up-conversion luminescent molecule part A and an up-conversion luminescent molecule part B, wherein the connection mode of the up-conversion luminescent molecule part A and the up-conversion luminescent molecule part B is ABA type, wherein the structure of the up-conversion luminescent molecule part A is as follows: Wherein, the upconversion luminescent molecule B is XCl3(THF)3, X is selected from one of the lanthanide metals Tm, Yb, and Er, and the molecular formula of the single molecule upconversion luminescent molecule containing the chiral group after assembly includes: 、 or One of them.

2. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 1, characterized in that: S1 includes the following steps: S11: Spin-coating photoresist on a pure silicon wafer, photolithography the external electrode of the gate to obtain a first negative film, evaporating chromium and gold electrodes on the first negative film to obtain a second negative film, immersing the second negative film in an acetone solution to remove the resist, and obtaining a third negative film; S12: Spin-coating photoresist on the third substrate, and performing ultraviolet photolithography on the gate electrode to obtain a bottom gate; S13: coating an aluminum film on the surface of the bottom gate by thermal evaporation, then placing the bottom gate in an acetone solution to remove the glue, and obtaining a dielectric layer of aluminum oxide by natural oxidation; S14: A hafnium oxide film is plated on the aluminum oxide surface of the dielectric layer using an atomic beam deposition technique to obtain a dielectric layer.

3. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 2, characterized in that: 6-8nm chromium and 30-40nm gold electrodes are evaporated on the first bottom film; 30-40nm aluminum film is plated on the surface of the bottom grid; 3-10nm hafnium oxide film is plated on the aluminum oxide surface of the dielectric layer.

4. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 2, characterized in that: S2 includes the following steps: S21: performing chemical vapor deposition on a copper sheet to obtain a single-layer graphene, adhering the copper sheet containing the single-layer graphene to a glass sheet with an adhesive tape, spin-coating polymethyl methacrylate (PMMA), etching the back of the copper sheet using oxygen plasma, soaking the copper sheet containing the single-layer graphene in a ferric chloride solution, removing the copper sheet at the bottom of the graphene, respectively soaking in a hydrochloric acid solution and an ultrapure water solution, and then removing the surface PMMA to obtain a graphene electrode; S22: photolithographically forming strips on the graphene electrode, exposing the strips to ultraviolet light, removing the photoresist outside the strips using a developer, and then performing oxygen plasma etching to obtain a silicon wafer having graphene strips; S23: exposing the silicon wafer with graphene strips to ultraviolet light, and coating a magnetic material on one side of the silicon wafer with graphene strips using a magnetron sputtering technique to obtain a silicon wafer containing a magnetic electrode; S24: exposing the silicon wafer containing the magnetic electrode to ultraviolet light, and evaporating chromium and gold electrodes on the other side of the silicon wafer having the graphene strips to obtain a graphene array electrode.

5. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 4, characterized in that: Plating 8-10 nm of chromium and 70 nm of magnetic material on one side of the silicon wafer having the graphene strips; 8-10 nm chromium and 60-80 nm gold electrodes are evaporated on the other side of the silicon wafer with the graphene strips.

6. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 1, characterized in that: S3 includes the following steps: S31: etching the graphene array electrode using electron beam exposure, and then developing it using a developer to obtain a graphene array electrode containing dotted lines; S32: using oxygen plasma to etch the graphene array electrode containing the dotted line, and then using a semiconductor parameter instrument and a room temperature probe station to perform a real-time on-off test on the graphene array electrode to obtain a pair of point electrodes with graphene nano-gaps.

7. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 6, characterized in that: The dotted lines on the graphene array electrode containing dotted lines are 150 nm long and 5 nm wide.

8. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 1, characterized in that: S4 includes the following steps: After the two flasks are sealed, they are repeatedly evacuated to place them in a nitrogen environment. 10 ml of anhydrous pyridine is drawn with a syringe and injected into the two flasks in the nitrogen environment. The reaction is continued for more than 48 hours to obtain a device with upconversion luminescent molecule A parts connected at both ends.

9. The method for preparing a single photon source based on an up-conversion optoelectronic device according to claim 1, characterized in that: The molar ratio of the up-conversion luminescent molecule A to 1-(3-dimethylaminopropyl)-3-2-ethylcarbodiimide hydrochloride is 1:20-1:40.

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