Single photon source based on up-conversion photoelectric device and preparation method thereof

Abstract

The invention relates to the field of molecular photoelectric devices, and provides a single photon source based on an up-conversion photoelectric device and a preparation method thereof, and the preparation method comprises the steps: 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)-3-2-ethylcarbodiimide hydrochloride and an up-conversion luminescent molecule A part into the two-neck flask, adding anhydrous pyridine into the two-neck flask in a nitrogen environment, and stirring to obtain a graphene nano gap point electrode pair; and putting the device connected with an up-conversion luminescent molecule part A at two ends and an up-conversion luminescent molecule part B containing lanthanide metal into a tetrahydrofuran solution for molecular system chelation to obtain the single-molecule up-conversion photoelectric device containing the chiral group. A liquid metal Ga2O3 protective layer is plated on a single-molecule up-conversion photoelectric device, so that a single photon source is obtained, and the stability and the anti-interference capability of the single photon source are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular optoelectronic devices, and in particular to a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof. Background Art

[0002] Quantum information technology is an emerging interdisciplinary subject. The core of this technology is to use quantum state characteristics such as quantum superposition and quantum entanglement to achieve efficient storage, processing and transmission of information, thereby surpassing traditional information technology in terms of computing power, information security and sensor measurement accuracy. Photons, as ideal physical carriers in quantum information technology, have strong anti-interference ability, long decoherence time and rich degrees of freedom. These characteristics of photons make them show great application potential in the fields of quantum communication, quantum computing and quantum measurement. In order to further realize the application of quantum photonics, three technologies are needed as support, including photon counters, linear and nonlinear photon circuits and single photon sources. These technologies are the core components of building quantum communication and quantum computing systems. In recent years, great progress has undoubtedly been made in photon counters and photon circuits, but the lack of single photon sources has undoubtedly hindered the further development of quantum technology. Single photon sources are the basic resources for realizing quantum communication and quantum computing. Their 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 of quantum secure communication.

[0003] A single-photon source refers to a light source that can produce a single photon. It is characterized by emitting only one photon at a time, and the emission is deterministic, so it is also called anti-bunching. The preparation of efficient, stable, reliable and easily available single-photon sources is one of the bottlenecks restricting the development of related technologies. To achieve a single-photon source that can be used for quantum communication, it is necessary to have high emission efficiency, controllable emission wavelength, high purity, high homogeneity, highly 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 radiation or regulation of quantum dots, diamond color centers, etc., but their application in quantum technology is limited due to limitations such as their own charge. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a single photon source based on an up-conversion optoelectronic device and a preparation method thereof, which enhances the stability and anti-interference ability of the single photon source.

[0005] The present invention provides a single photon source based on an up-conversion optoelectronic device and a preparation method thereof, comprising: 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.

[0006] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S1 comprises 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.

[0007] According to a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, 6-8 nm chromium and 30-40 nm gold electrodes are evaporated on the first substrate; a 30-40 nm aluminum film is plated on the surface of the bottom gate; and a 3-10 nm hafnium oxide film is plated on the aluminum oxide surface of the dielectric layer.

[0008] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S2 comprises 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.

[0009] 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 chromium and 70 nm magnetic material are plated 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.

[0010] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S3 comprises 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.

[0011] According to a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, the dotted line on the graphene array electrode containing dotted lines is 150 nm long and 5 nm wide.

[0012] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S4 comprises 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.

[0013] According to a single-photon source based on an upconversion photoelectric device and a preparation method thereof provided by the present invention, the single-molecule upconversion luminescent molecule in the single-molecule upconversion photoelectric device containing a chiral group comprises an upconversion luminescent molecule part A and an upconversion luminescent molecule part B, and the connection mode of the upconversion luminescent molecule part A and the upconversion luminescent molecule part B is ABA type, wherein the structure of the upconversion luminescent molecule part A is as follows: Wherein, the upconversion luminescent molecule B comprises XCl3(THF)3, X comprises 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 comprises: , or One of them.

[0014] 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)-3-2-ethylcarbodiimide hydrochloride is 1:20-1:40.

[0015] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: According to the single-photon source based on up-conversion optoelectronic device and the preparation method thereof of the embodiment of the present invention, by designing a single-molecule up-conversion optoelectronic device containing a chiral group, the problem of limiting the preparation of the single-photon source is solved, and the ability of the single-photon source to emit circularly polarized light is increased, thereby enhancing the certainty of the polarization of the single photon emitted by the single-photon source, so that the photon has a stronger ability to resist stray interference and improves the homogeneity of the photon; at the same time, because the up-conversion luminescent molecules in the up-conversion optoelectronic device have a strong resistance to photobleaching, the stability and continuity of the luminescence of the single-photon source are improved, thereby promoting the development of quantum information technology.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1It is a structural schematic diagram of a single photon source based on an up-conversion optoelectronic device and a single photon source prepared by a preparation method thereof provided by the present invention.

[0019] 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.

[0020] Figure 3 It is a luminescence diagram of a single-photon source prepared by a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention.

[0021] Figure 4 It is a characteristic diagram of the current variation with gate voltage of a single-molecule up-conversion photoelectric device provided by the present invention based on a single-photon source of an up-conversion photoelectric device and a preparation method thereof when the bias voltage is 0.2V.

[0022] Figure 5 It is a characteristic diagram of the current variation with gate voltage of a single-molecule up-conversion photoelectric device provided by the present invention based on a single-photon source of an up-conversion photoelectric device and a preparation method thereof when the bias voltage is -0.2V.

[0023] Reference numerals: 1. Graphene nanogap point electrode pair; 2. Gold electrode; 3. Liquid metal Ga2O3 protective layer; 4. Magnetic electrode; 5. Silicon wafer; 6. Upconversion luminescent molecules. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are 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.

[0025] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0027] Upconversion luminescence mainly involves several key nonlinear optical processes, including excited state absorption, energy transfer upconversion, photon avalanche, etc., which enable the material to convert lower energy photons into higher energy photons, and 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 a functional molecule and connects it to a graphene array electrode with a nanogap, which can ensure the generation of a single photon, and utilizes the luminescent properties of the upconversion luminescent molecule itself, and controls by applying a specific low-energy light source or a small bias voltage or gate voltage to achieve the stable emission of a single high-energy photon.

[0028] Since the designed upconversion luminescent molecules carry chiral groups, this not only enhances the circularly polarized luminescence characteristics of the single-photon source, but also introduces spin current by constructing magnetic electrodes, further improving the circularly polarized luminescence performance of the single-photon source. At the same time, it improves the homogeneity of the photons emitted by the single-photon source, making it possible to achieve high-purity, high-quality, high-stability, and high-continuity circularly polarized single-photon emission, providing strong support for fields such as optical quantum information processing and quantum communication.

[0029] Figure 1 It is a structural schematic diagram of a single photon source based on an up-conversion optoelectronic device and a single photon source prepared by a preparation method thereof provided by the present invention.

[0030] The present invention provides a single photon source based on an up-conversion optoelectronic device and a preparation method thereof, such as Figure 1 As shown, a single photon source based on an up-conversion optoelectronic device and a preparation method thereof include: S1: preparing a dielectric layer; S2: preparing a graphene array electrode on the dielectric layer; S3: Based on the graphene array electrode, a graphene nanogap point electrode pair 1 is constructed; S4: placing the graphene nanogap point electrode pair 1 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 3 on the single-molecule up-conversion optoelectronic device containing chiral groups to obtain a single-photon source.

[0031] In this embodiment, by designing a single-molecule up-conversion optoelectronic device containing a chiral group, the problem of limiting the preparation of a single-photon source is solved, and the ability of the single-photon source to emit circularly polarized light is increased, thereby enhancing the certainty of the polarization of single photons emitted by the single-photon source, making the photons more resistant to stray interference and improving the homogeneity of the photons; at the same time, because the up-conversion luminescent molecule 6 in the up-conversion optoelectronic device has a strong resistance to photobleaching, the stability and continuity of the luminescence of the single-photon source are improved, thereby promoting the development of quantum information technology.

[0032] According to some embodiments of the present invention, the prepared single-molecule up-conversion photoelectric device is taken out from the two-necked flask, washed three times with acetone and ultrapure water respectively, and finally the surface is dried with nitrogen for later use.

[0033] According to some embodiments of the present invention, a layer of liquid metal Ga2O3 with a thickness of 1-20 nm is prepared on the surface of the single-molecule up-conversion optoelectronic device as a protective layer. Preferably, the thickness of the liquid metal Ga2O3 protective layer 3 is 15 nm.

[0034] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S1 comprises the following steps: S11: Spin-coating photoresist on a pure silicon wafer 5, photolithography the external electrode of the gate to obtain a first negative film, evaporating chromium and gold electrodes 2 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.

[0035] According to some embodiments of the present invention, the surface of the pure silicon wafer is covered with 300-400 nm of silicon oxide, and preferably, the thickness of the silicon oxide is 350 nm.

[0036] According to some embodiments of the present invention, the gate lead electrode photolithographically formed on the first substrate is used for subsequent probe testing and calibration of subsequent photolithography.

[0037] According to some embodiments of the present invention, the bottom gate needs to be connected to the evaporated metal.

[0038] 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, and after debonding with acetone, a dielectric layer of aluminum oxide is obtained by natural oxidation.

[0039] According to a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, 6-8 nm chromium and 30-40 nm gold electrode 2 are evaporated on the first substrate; a 30-40 nm aluminum film is plated on the surface of the bottom gate; and a 3-10 nm hafnium oxide film is plated on the aluminum oxide surface of the dielectric layer.

[0040] According to some preferred embodiments of the present invention, 7nm chromium and 35nm gold electrode 2 are evaporated on the first substrate; 35nm aluminum film is plated on the bottom gate surface; and 6nm hafnium oxide film is plated on the aluminum oxide surface of the dielectric layer.

[0041] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S2 comprises 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; 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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; According to some embodiments of the present invention, ultraviolet photoresist is used to photolithography strips with a width of 40 μm and a length of 200 μm on the graphene electrode, and the strips are exposed by ultraviolet photolithography, wherein the portion of the strip to be retained is selected to be protected by the photoresist, and the remaining portion is removed by a developer to expose the graphene layer under the photoresist, and the exposed graphene layer is etched by oxygen plasma RIE. After the etching is completed, the residual photoresist is removed by acetone to obtain a silicon wafer with graphene strips.

[0046] 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 4; According to some embodiments of the present invention, Figure 1 As shown, ultraviolet photoresist is spin-coated on the silicon wafer with graphene strips, and the electrode part is photolithographically processed, and then developed after ultraviolet exposure. After development, 8-10nm chromium and 70nm magnetic material are plated on the silicon wafer with graphene strips using magnetron sputtering technology, and the magnetic material includes any one of iron, cobalt or nickel metals; finally, acetone is used to remove excess metal and photoresist to obtain the magnetic electrode 4. The magnetic electrode 4 realizes efficient spin-selective transmission, and only allows electrons with a specific spin direction to pass through, so a spin-polarized current is generated in the experiment, so that the silicon wafer containing the magnetic electrode 4 can emit circularly polarized photons, thereby improving the certainty of single photon polarization.

[0047] S24: The silicon wafer containing the magnetic electrode 4 is exposed to ultraviolet light, and chromium and gold electrodes 2 are evaporated on the other side of the silicon wafer having the graphene strips to obtain a graphene array electrode.

[0048] According to some embodiments of the present invention, ultraviolet photoresist is spin-coated on the silicon wafer containing the magnetic electrode 4, and the gold electrode 2 on the other side is photolithographically formed. After ultraviolet exposure, the gold electrode 2 is developed. After development, 8 nm chromium and 80 nm gold are evaporated on the silicon wafer containing the magnetic electrode 4 by a thermal evaporation method as the other end electrode. Finally, the excess metal and photoresist are removed by acetone to obtain the gold electrode 2. Figure 1 As shown, a graphene array electrode is finally obtained. The portion between the magnetic electrode 4 and the gold electrode 2 is called a graphene channel. Figure 1 shown.

[0049] According to some embodiments of the present invention, the conductivity of the graphene array electrode is tested and screened, and the conductivity of the graphene array electrode is tested at a voltage of 50mV using an SM-6-probe station. The graphene array electrode with a conductivity of the order of 10μA can be used to prepare the graphene nanogap point electrode pair 1.

[0050] 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 chromium and 70 nm magnetic material are plated on one side of the silicon wafer having the graphene strips; On the other side of the silicon wafer with the graphene strips, 8-10 nm chromium and 60-80 nm gold electrodes 2 are evaporated.

[0051] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S3 comprises 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; According to some embodiments of the present invention, PMMA is spin-coated on a graphene array electrode, an electron beam is used to etch a dotted line 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 isopropyl alcohol to methyl isobutyl ketone 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, i.e., a graphene dot electrode.

[0052] 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 graphene nanogap point electrode pair 1.

[0053] According to some embodiments of the present invention, the nanogap of the graphene nanogap point electrode pair 1 is 1-10 nm.

[0054] According to a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, the dotted line on the graphene array electrode containing dotted lines is 150 nm long and 5 nm wide.

[0055] According to a single photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention, S4 comprises 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.

[0056] Figure 3 It is a luminescence diagram of a single-photon source prepared by a single-photon source based on an up-conversion optoelectronic device and a preparation method thereof provided by the present invention. Figure 4 It is a characteristic diagram of the current variation with gate voltage of a single-molecule up-conversion photoelectric device provided by the present invention based on a single-photon source of an up-conversion photoelectric device and a preparation method thereof when the bias voltage is 0.2V. Figure 5 It is a characteristic diagram of the current variation with gate voltage of a single-molecule up-conversion photoelectric device provided by the present invention based on a single-photon source of an up-conversion photoelectric device and a preparation method thereof when the bias voltage is -0.2V.

[0057] According to a single-photon source based on an upconversion photoelectric device and a preparation method thereof provided by the present invention, the single-molecule upconversion luminescent molecule 6 in the single-molecule upconversion photoelectric device containing a chiral group includes an upconversion luminescent molecule part A and an upconversion luminescent molecule part B, and the connection mode of the upconversion luminescent molecule part A and the upconversion luminescent molecule part B is ABA type, wherein the structure of the upconversion luminescent molecule part A is as follows: Wherein, the upconversion luminescent molecule B comprises XCl3(THF)3, X comprises one of the lanthanide metals Tm, Yb, and Er, and the molecular formula of the single molecule upconversion luminescent molecule 6 containing a chiral group after assembly comprises: , or One of them.

[0058] According to some embodiments of the present invention, the specific synthesis route of the upconversion luminescent molecule A is as follows: In an anhydrous and oxygen-free nitrogen atmosphere, 2 mmol , 6mmol trimethylethynylsilane, 0.04mmol Pd(PPh3)4 and 0.04mmol CuI and 250ml triethylamine. React at 90°C for 1 day under nitrogen. After cooling, pour the reactant into water and extract three times with dichloromethane (100ml), and remove excess solvent by filtration. Dissolve the obtained solid in ethanol, add 20ml K2CO3, and react at room temperature for 1 day. Remove excess ethanol by filtration, wash the solid with dichloromethane, spin dry the obtained solution, and then purify the product by column chromatography to obtain .

[0059] In a nitrogen atmosphere without water or oxygen, 2 mmol , 1.8mmol , 0.04mmol Pd(PPh3)4 and 10ml K2CO3 (20mmol) aqueous solution and 250ml toluene. Reflux for 1 day under nitrogen. After cooling, pour the reactant into water and extract three times with dichloromethane (100ml). Remove the excess solvent by filtration, then purify the product by column chromatography and obtain by chiral separation. .

[0060] In an anhydrous and oxygen-free nitrogen atmosphere, 1.5 mmol , 2mmol , 0.04mmol Pd(PPh3)4 and 10ml K2CO3 (20mmol) aqueous solution and 250ml toluene. Reflux for 1 day under nitrogen atmosphere. After cooling, the reactant was poured into water and extracted three times with dichloromethane (100ml). The excess solvent was removed by filtration, and the product was then purified by column chromatography to obtain .

[0061] In an anhydrous and oxygen-free nitrogen atmosphere, 1.5 mmol , 2mmol , 0.04mmol Pd(PPh3)4 and 10ml K2CO3 (20mmol) aqueous solution and 250ml toluene were refluxed under nitrogen for 1 day. After cooling, the reactant was poured into water and extracted three times with dichloromethane (100ml). The excess solvent was removed by filtration, and the product was purified by column chromatography to obtain .

[0062] In an anhydrous and oxygen-free nitrogen atmosphere, 1.5 mmol , 2mmol , 0.04mmol Pd(PPh3)4 and 10ml K2CO3 (20mmol) aqueous solution and 250ml toluene. Reflux for 1d under nitrogen. After cooling, the reactant was poured into water and extracted three times with dichloromethane (100ml). The excess solvent was removed by filtration, and the product was then purified by column chromatography to obtain .

[0063] In an anhydrous and oxygen-free nitrogen atmosphere, 0.3 mmol and excess CF3COOH and 100 ml of dichloromethane, reacted under nitrogen for 1 day. After cooling, the reactant was poured into water and extracted three times with dichloromethane (100 ml), the excess solvent was removed by filtration, and the product was purified by column chromatography to obtain .

[0064] According to some embodiments of the present invention, Figure 1As shown, a silicon wafer is used as a substrate, a gold electrode 2 is evaporated on one side, a magnetic electrode 4 is prepared on the other side, a graphene nanogap point electrode pair 1 with a nanogap is prepared between the two, a single upconversion luminescent molecule 6 is introduced by forming an amide bond, and a single molecule upconversion photoelectric device is obtained. A layer of liquid metal Ga2O3 is prepared on its surface as a protective layer to obtain a single photon source.

[0065] According to some embodiments of the present invention, Figure 3 As shown, the light spot (such as Figure 3 The dotted box (shown in the enlarged area) is a single photon emitted by a single photon source, which has high purity and good stability. Since the functional molecule of the single-molecule up-conversion photoelectric device is a single up-conversion luminescent molecule 6, it can only emit one photon at a time under a given excitation, and the photons can be generated by light source excitation or electric field excitation. Since the up-conversion luminescent molecule 6 can be regulated by an external electric field, the energy level distribution of the electrons in the up-conversion material is changed by applying different gate voltages, affecting the energy level transition of the ions, so that the relative position between the frontier molecular orbital and the electrode Fermi level is controllably changed, thereby achieving the emission of photons of different wavelengths. At the same time, under a specific gate voltage and bias, the electrons can be excited to a specific energy level, thereby ensuring that the emitted single photons have a high purity. At the same time, since the up-conversion luminescent molecule 6 has chirality, the ability of the single-electron source to emit circularly polarized light is increased, and the certainty of the polarization of the single photon emitted by the single-electron source is further enhanced, so that the photons have a stronger ability to resist stray interference, and the homogeneity of the photons is also improved.

[0066] According to some embodiments of the present invention, the spectral characteristics of the emitted photons can be regulated during the test process. The test temperature can be adjusted in the range of 90~350K by using a TTPX low-temperature probe station, or a femtosecond laser can be introduced to apply a light source of specific power and specific wavelength to the single-molecule up-conversion photoelectric device, or the spectral characteristics of the emitted single photons can be regulated by applying magnetic fields of different intensities using a comprehensive physical property measurement system PPMS, and at the same time, the narrow-band emission characteristics of the up-conversion luminescent molecule 6 are utilized, and the emitted photons generally have higher spectral purity and narrower bandwidth, thereby further improving the purity and emission efficiency of the single-photon source.

[0067] According to some embodiments of the present invention, a single upconversion luminescent molecule 6 is used as a functional molecule, and firstly, the amino groups (-NH2) at both ends of the single upconversion luminescent molecule A are amide bonded with the carboxyl groups (-COOH) at the ends of the graphene nanogap point electrode pair 1, and then the single molecule upconversion photoelectric device is chelated with the upconversion luminescent molecule B containing a lanthanide metal, wherein the lanthanide metal includes any one of Tm, Yb, and Er, to construct a single photon source based on a single molecule upconversion photoelectric device. Figure 4 and Figure 5As shown, under a certain bias voltage, the conductivity changes with the gate voltage, which not only shows that a single upconversion luminescent molecule 6 is successfully connected to the graphene nanogap point electrode pair 1, but also that the gate voltage can regulate it.

[0068] Among them, the upconversion luminescent molecule 6 is composed of lanthanide metals, and the upconversion luminescent molecule 6 has the following advantages: (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, high-quality photons.

[0069] (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 using a smaller bias voltage, which reduces energy consumption to a certain extent and improves the efficiency of the single-photon source.

[0070] (3) High collection rate: Since the upconversion luminescent molecule 6 usually has a long luminescence lifetime, it is convenient to collect and analyze photons within a certain time range.

[0071] (4) High continuity: Since the upconversion luminescent molecule 6 has strong photobleaching properties, the process of emitting photons is stable and photons can be emitted continuously.

[0072] 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)-3-2-ethylcarbodiimide hydrochloride is 1:20-1:40.

[0073] Compared with the prior art, 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: 1. Based on the preparation of graphene-based single-molecule optoelectronic devices, a single upconversion luminescent molecule is selected as the functional molecule to ensure the generation of a single photon. The upconversion luminescent molecule makes the single-photon source have the characteristics of high stability, long lifetime of emitted photons, and low-energy excitation.

[0074] 2. Using a single upconversion luminescent molecule as a functional molecule, firstly, the amino groups (-NH2) at both ends of the A part of the single upconversion luminescent molecule are amide bonded with the carboxyl groups (-COOH) at the end of the graphene nanogap point electrode, and then the single-molecule upconversion optoelectronic device is chelated with the lanthanide metal 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, the upconversion luminescent molecule has the characteristics of being able to convert lower-energy photons into higher-energy photons. By applying a light source, a small bias voltage, and an external field such as a gate voltage to control the emission of single photons, the generation of wavelength-controllable single photons can be achieved, which provides technical support for the emission of high-purity, high-quality, and high-collection-rate single photons, and lays the foundation for the further development of quantum information technology.

[0075] 3. Through the construction of magnetic electrodes, spin current is introduced to realize the characteristics of circularly polarized luminescence. At the same time, since the designed upconversion luminescent molecules have chiral groups, the ability of single-photon source to emit circularly polarized luminescence is increased, and the certainty of the polarization of single photons emitted by the single-photon source is further enhanced, making the photons more resistant to stray interference and improving the homogeneity of photons. At the same time, since the upconversion luminescent molecules have strong resistance to photobleaching, the stability and continuity of single-photon source luminescence are improved, promoting the development of quantum information technology.

[0076] 4. The emission of a single photon is achieved using a single-molecule upconversion optoelectronic device as a carrier. The device is miniaturized and has strong scalability. The prepared optoelectronic device has 300 conductive channels and is highly integrable, providing a research basis for the study of multi-photon quantum computing and quantum communication.

[0077] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single photon source based on an upconversion optoelectronic device and a method for preparing the same, 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.

2. The single photon source based on up-conversion optoelectronic device and the preparation method thereof 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 single photon source based on up-conversion optoelectronic device and the preparation method thereof 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 single photon source based on up-conversion optoelectronic device and the preparation method thereof 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 single photon source based on up-conversion optoelectronic device and the preparation method thereof 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 single photon source based on up-conversion optoelectronic device and the preparation method thereof 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 single photon source based on up-conversion optoelectronic device and the preparation method thereof 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 single photon source based on up-conversion optoelectronic device and the preparation method thereof 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 single photon source based on up-conversion optoelectronic device and the preparation method thereof according to claim 1, characterized in that: 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 comprises XCl3(THF)3, X comprises 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 comprises: 、 or One of them.

10. The single photon source based on up-conversion optoelectronic device and the preparation method thereof 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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