A method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects

Abstract

The method for preparing patterned quantum light sources on a large scale based on photoactivated carbon defects of the present invention comprises the following steps: S1, peeling off a two-dimensional hBN sheet; S2, transferring the two-dimensional hBN sheet prepared in step S1 to a PDMS sheet substrate; S3, transferring the two-dimensional hBN sheet to a silicon dioxide substrate through the PDMS sheet substrate; S4, irradiating the two-dimensional hBN sheet with a high-power density continuous laser, and forming a quantum light source through the excitation of the high-power continuous laser; S5, exciting the hBN sheet quantum light source obtained in step S4 with a low-power laser, and the quantum light source generates fluorescence; S6, moving the substrate sheet with the hBN sheet to control the movement of the area of ​​the hBN sheet irradiated by the laser, and realizing a customized patterned large-scale quantum light source on the hBN sheet. The present invention provides a simple, efficient, large-scale preparation method for high-brightness, high-repeatability quantum light sources.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano photonic devices, and in particular relates to a method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects. Background Art

[0002] Two-dimensional van der Waals materials are rapidly becoming a promising platform for studying physical phenomena and technologies in the fields of electronics, phononics, and nanophotonics. For example, two-dimensional materials are found in field-effect tunnel transistors, hyperbolic phonon polaritons, and single-photon sources. Hexagonal boron nitride (hBN), as an important member of the two-dimensional material family, can realize quantum light sources based on various defects at room temperature, and has the characteristics of high brightness and high quantum efficiency. At the same time, due to the large band gap of hBN (about 6 eV), hBN has a high tolerance to defects. By introducing different defects, such as boron vacancies, nitrogen vacancies, and substitutional antisite defects, defect quantum light sources spanning the ultraviolet, visible, and infrared spectral ranges have been realized. Therefore, hBN has become a strong candidate material for the preparation and integration of quantum light sources in the field of quantum information technology. Many experimental results and computational analyses have shown that there are a large number of carbon-related defects in hBN, including C B , C N and C 2 C N In addition, due to its high mechanical strength and the flexibility of two-dimensional materials, hBN shows high applicability in the application of on-chip quantum micro-nano photonics devices and can be effectively integrated into various micro-nano structures.

[0003] In order to activate and optimize quantum light sources in hBN defects, people have adopted a variety of different methods, such as thermal annealing, substrate strain induction, ion radiation, plasma treatment, metal organic vapor phase epitaxy, molecular beam epitaxy, etc. These advances have greatly improved the preparation and manipulation of hBN quantum light sources. However, most methods usually require expensive equipment and complex preparation techniques, and the configuration and distribution of defects are mostly random. Existing femtosecond pulse laser processing, ion radiation, and molecular beam epitaxy all artificially introduce additional boron-related or nitrogen-related defects into hBN, and thermal annealing is often required to activate defect quantum light sources. Therefore, there is still a need for a simple and efficient method to use uniformly distributed and positionally controllable carbon defects in hBN to generate high-brightness, high-repeatability quantum light sources on a large scale.

[0004] In addition, hBN is often used as an insulating layer and protective material in optoelectronic devices. Research on the patterning of hBN is also relatively rare. In existing reports, patterned luminescence on hBN is generally achieved through high-energy electron beam irradiation, femtosecond laser processing, or the use of arrayed nanopillars to introduce strain. However, these methods are costly and difficult to operate. High-energy electron beam irradiation will produce a large number of defects in hBN materials. Affected by factors such as the selection of irradiation parameters, the intrinsic properties of the material, and the randomness of the irradiation process, it is difficult to completely and accurately control these defects, affecting the predictability and repeatability of the luminescence performance caused by the irradiation treatment. In addition, high-energy electron beams will cause a certain degree of radiation damage to the hBN crystal structure, affecting the optical properties and long-term stability of the material. Although femtosecond laser is an effective means to introduce defects in hBN materials, the femtosecond laser processing equipment is complex and costly, and the defect structure produced is random. The preparation of nanopillar arrays usually requires complex lithography and etching steps to introduce strain defects, which is cumbersome and easy to introduce additional defects and contamination. Moreover, the strain introduced by nanopillars may be unevenly distributed in the material, resulting in spatial variations in the luminous intensity and wavelength of the quantum light source.

[0005] Therefore, how to solve the problems of high cost and complex process of quantum light source production, and provide a simple, efficient, patterned large-scale method for preparing high-brightness, high-repeatability quantum light sources is a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0006] The purpose of the present invention is to provide a method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects in order to address the problems in the prior art.

[0007] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] A method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects, characterized in that it comprises the following steps:

[0009] S1, peeling off the 2D hBN flakes;

[0010] S2, transferring the two-dimensional hBN sheet prepared in step S1 to a PDMS sheet substrate;

[0011] S3, transferring the two-dimensional hBN sheet to the silicon dioxide substrate through the PDMS sheet substrate;

[0012] S4, using high-power density continuous laser to irradiate the two-dimensional hBN thin film. Through the excitation of high-power continuous laser, the energy of the incident photon is much greater than the potential barrier that the carbon-related defects need to overcome in the lattice migration, and the thermal effect in the hBN thin film is accumulated, and the thermal motion of carbon-related defects is intensified. The carbon defects originally uniformly distributed in the laser irradiation area are enriched under the action of high-power continuous laser, and combine in the laser irradiation area to form lower energy C 2 C N , C 2 C B , C 2 Defect states such as , thus forming a quantum light source;

[0013] S5, using a low-power laser to excite the hBN thin film quantum light source obtained in step S4, the quantum light source generates fluorescence, and the presence of carbon-enriched related defects is characterized by two new characteristic peaks appearing on the Raman spectrum;

[0014] S6, moving the substrate sheet with the hBN thin sheet to control the movement of the area of ​​the hBN thin sheet irradiated by the laser, and realizing a customized patterned large-scale quantum light source on the hBN thin sheet.

[0015] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0016] As a preferred technical solution of the present invention: in step S1, a two-dimensional hBN sheet is mechanically peeled off from a hexagonal boron nitride crystal using Scotch tape, wherein the thickness of the two-dimensional hBN sheet is 5-50 nm.

[0017] As a preferred technical solution of the present invention: in step S2, the hBN flakes obtained in step S1 are transferred to a PDMS flake substrate, and mechanically separated and transferred by utilizing the viscosity of the PDMS flake substrate.

[0018] As a preferred technical solution of the present invention: in step S3, the PDMS sheet base and hBN are attached to a silicon dioxide substrate, heated at 80°C for ten minutes to make the PDMS sheet base lose its stickiness and then peeled off, and the hBN sheet is transferred to the silicon dioxide substrate.

[0019] As a preferred technical solution of the present invention: in step S6, the movement of the substrate sheet with the hBN thin sheet is controlled by a high-precision electric three-dimensional displacement platform to control the movement of the laser processing area in step S4, and the movement of the laser processing area is controlled by the three-dimensional displacement platform to realize a customized patterned large-scale quantum light source on the hBN thin sheet.

[0020] As a preferred technical solution of the present invention: it also includes step S7, in order to observe the hBN patterned quantum light source obtained in step S6, secondary excitation is adopted by a continuous light laser with low power and large spot.

[0021] As a preferred technical solution of the present invention: in step S7, the patterned observation of the hBN quantum light source is at a wavelength of 400-550 nm, a power of no more than 0.1 mW, and a spot area of ​​no less than 10 μm 2 under continuous laser excitation.

[0022] As a preferred technical solution of the present invention: the laser wavelength irradiated to the hBN sheet and stimulated the carbon-related defect enrichment in step S4 is 500-550 nm, and the power density is not less than 10 mW / μm 2 .

[0023] As a preferred technical solution of the present invention: in step S5, the laser wavelength of the quantum light source that excites hBN to produce fluorescence is 500-550 nm, and the power density is not higher than 0.1 mW / μm 2 ;

[0024] The maximum range of the wavelength of the hBN quantum light source is 550-800 nm;

[0025] The two new characteristic peaks in the Raman spectrum are generated after carbon defect enrichment, with peak values ​​of about 1330 cm -1 and about 1602 cm -1 .

[0026] Compared with the prior art, the method of the present invention for preparing patterned quantum light sources on a large scale based on photoactivated carbon defects has the following beneficial effects: based on the thermal effect enrichment of carbon-related defects in the hBN lattice structure under high-power continuous laser processing, a large-scale quantum light source is prepared using hexagonal boron nitride, and the characteristic of generating fluorescence under low laser excitation is achieved, and the carbon-related defects can be directly characterized by Raman spectroscopy, and a customizable patterned large-scale quantum light source is achieved on a two-dimensional material hBN sheet through controllable laser processing area. The quantum light source of the present invention has the characteristics of simple implementation method, high repeatability, high light source intensity, good controllability, low production cost, no need to actively introduce defects, and has important application value in the fields of quantum optics, optoelectronic devices, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of the large-scale quantum light source of the present invention;

[0028] Figure 2 Schematic diagram of the excitation and detection system of the large-scale quantum light source of the present invention;

[0029] Figure 3 The Raman spectrum of the large-scale quantum light source under laser excitation of the present invention;

[0030] Figure 4 The fluorescence spectrum of the large-scale quantum light source under laser excitation of the present invention;

[0031] Figure 5 The patterned fluorescence of the large-scale quantum light source under laser excitation described in the present invention;

[0032] In the attached drawings, there are hexagonal boron nitride thin film 1; silicon dioxide substrate sheet 2; high-power continuous laser 3; camera 4; spectrometer 5; reflector 6; filter 7; laser 8; dichroic mirror 9; and objective lens 10. DETAILED DESCRIPTION

[0033] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] A method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects of the present invention comprises the following steps:

[0035] S1, mechanical exfoliation of 2D hBN flakes from hBN crystals using Scotch tape;

[0036] S2, transferring the hBN sheet obtained in step S1 to the PDMS sheet substrate;

[0037] S3, attaching the PDMS sheet substrate and hBN in step S2 to a silicon dioxide substrate, heating at 80° C. for ten minutes to make the PDMS sheet substrate lose its stickiness and then peeling it off, and the hBN sheet is transferred to the silicon dioxide substrate;

[0038] S4, using a high-power density continuous laser to irradiate the hBN thin slice obtained in step S3, a small amount of carbon-related defects are evenly distributed in the hBN lattice structure. Under the high-power continuous laser excitation, since the energy of the incident photon is much greater than the potential barrier that the carbon-related defects need to overcome in the lattice migration, and the continuous laser excitation causes the thermal effect of the hBN lattice to accumulate, the thermal motion of the carbon-related defects is intensified, and the carbon defects originally evenly distributed in the laser irradiation area are enriched under the action of the high-power continuous laser, and are combined in the laser irradiation area to form lower energy C 2 C N , C 2 C B , C 2 etc. defect states, thus forming a quantum light source;

[0039] S5, using a low-power laser to excite the hBN thin film quantum light source obtained in step S4, the quantum light source produces fluorescence, and the presence of carbon-enriched related defects is characterized by two new characteristic peaks appearing in the Raman spectrum;

[0040] S6, controlling the movement of the substrate sheet with the hBN sheet by a high-precision three-dimensional displacement platform to control the movement of the laser processing area in step S4, so as to realize a customized patterned large-scale quantum light source on the hBN sheet;

[0041] S7, in order to observe the hBN patterned quantum light source obtained in step S6, a low-power, large-spot continuous light laser is used for excitation.

[0042] Among them, hBN is hexagonal boron nitride, and PDMS is polydimethylsiloxane.

[0043] The present invention uses high-power density laser processing to specify a two-dimensional material hBN area, and induces the enrichment of carbon-related defects in the hexagonal boron nitride lattice structure and generates fluorescence through high-energy thermal effects. The carbon-related defects can be directly characterized by Raman spectroscopy. In addition, a high-precision electric three-dimensional displacement platform is used to control the movement of the laser processing area, so that a controllable patterned quantum light source at the micro-nano level can be realized on the hBN slice.

[0044] Furthermore, the two-dimensional hBN sheet is a two-dimensional material mechanically peeled from a hBN crystal, and has a thickness of 5-50 nm.

[0045] Furthermore, before step S2, the method further includes the following steps: ultrasonically cleaning the silicon dioxide substrate with acetone and ethanol respectively, and drying with nitrogen.

[0046] Furthermore, in step S2, the hBN sheet is mechanically separated and transferred by utilizing the viscosity of the PDMS sheet substrate.

[0047] Furthermore, in step S3, the temperature for heating the PDMS sheet substrate to eliminate viscosity is 80° C., and the heating time is 10 min.

[0048] Furthermore, in step S4, the laser wavelength irradiated to the hBN sheet and stimulated the carbon-related defect enrichment thereof is 500-550 nm, and the power density is not less than 10 mW / μm 2 .

[0049] Furthermore, the laser wavelength of the quantum light source that excites hBN to produce fluorescence in step S5 is 500-550 nm, and the power density is not higher than 0.1 mW / μm 2 .

[0050] Furthermore, the maximum range of the wavelength of the hBN quantum light source in step S5 is 550-800 nm.

[0051] Furthermore, the two new characteristic peaks of the Raman spectrum in step S5 are generated after carbon defect enrichment, and the peak values ​​are about 1330 cm -1and about 1602 cm -1 .

[0052] Furthermore, in step S6, the high-precision electric three-dimensional translation stage is used to carry and move the hBN thin slice, and the movement of the laser processing area is controlled by the three-dimensional translation stage, so that the patterning of the large-scale quantum light source can be customized.

[0053] Furthermore, the patterned observation of the hBN quantum light source in step S6 is performed at a wavelength of 400-550 nm, a power of no more than 0.1 mW, and a spot area of ​​no less than 10 μm 2 under continuous laser excitation.

[0054] Compared with the prior art, the present invention has the following technical effects: the method for preparing a large-scale quantum light source using hexagonal boron nitride involved in the present invention processes a two-dimensional material hBN thin slice by high-power continuous laser, and uses the thermal effect to activate the enrichment of carbon-related defects in the hexagonal boron nitride lattice, and can directly characterize low-content carbon defects by Raman spectroscopy, thereby realizing a large-scale quantum light source preparation with controllable position and high repeatability. In the present invention, hexagonal boron nitride hBN can generate fluorescence without actively introducing defects, which not only simplifies the preparation process, but also significantly improves the fluorescence stability and controllability, and greatly promotes the integrated application of materials in quantum light sources and other high-tech fields. In the present invention, the unique fluorescence characteristics brought by the naturally formed defects in hBN are used to achieve the stability of the quantum light source, and the single photon emission can be achieved by controlling the inherent defects, which simplifies the preparation process and further increases the controllability and integration. At the same time, by controlling the laser processing area, the patterning of the large-scale quantum light source is further realized, which has the advantages of simple structure, excellent performance, low cost, large scale and room temperature operation, and has important application value in the fields of quantum optics and optoelectronic devices.

[0055] Figure 1 This is a schematic diagram of the structure of a large-scale quantum light source based on high-power continuous laser processing of hexagonal boron nitride carbon-related defect-enriched luminescence. The hexagonal boron nitride two-dimensional material sheet 1 is obtained by mechanically peeling off the hexagonal boron nitride hBN crystal (purchased from HQ Graphene) with Scotch tape, and then the polydimethylsiloxane PDMS sheet substrate and the hexagonal boron nitride are attached to the silicon dioxide substrate sheet 2 as a whole. After heating at 80°C for ten minutes, the polyPDMS sheet substrate loses its stickiness and is peeled off. The hexagonal boron nitride is transferred to the silicon dioxide substrate sheet 2. The wavelength is 532 nm and the power density is not less than 10 mW / μm 2 The hBN slice is excited by high-power continuous laser 3, and the carbon-related defects in the lattice structure are enriched to form a large-scale quantum light source. The movement of the high-precision electric three-dimensional displacement platform is controlled to control the laser processing area, and the patterning of the large-scale quantum light source is achieved to complete the preparation.

[0056] Figure 2 Schematic diagram of the excitation and detection system of the large-scale quantum light source of the present invention, such as Figure 2 As shown, the hexagonal boron nitride sheet 1 is placed under a microscope, and the laser 8 emits a wavelength of 532 nm and a power density of not less than 10 mW / μm 2 The laser is reflected by the dichroic mirror 9, focused by the objective lens 10 and incident on the hexagonal boron nitride slice 1. The spectral information is collected by the objective lens 10, passes through the filter 7 and the reflector 6, and is collected by the spectrometer 5. The camera 4 is used to observe the position of the large-scale quantum light source of the hexagonal boron nitride slice 1.

[0057] Under high-power continuous laser excitation, a small amount of carbon-related defects are evenly distributed in the lattice structure of the hexagonal boron nitride sheet 1. Under high-power continuous laser excitation, since the energy of the incident photon is much greater than the potential barrier that the carbon-related defects need to overcome to migrate in the lattice, and continuous laser excitation causes the thermal effect of the hexagonal boron nitride lattice to accumulate, the thermal motion of the carbon-related defects intensifies, and the carbon defects originally evenly distributed in the laser irradiation area are enriched under the action of high-power continuous laser, and combine in the laser irradiation area to form lower energy C 2 C N , C 2 C B , C 2 Defect states such as , thus forming a quantum light source, the carbon defect enrichment characteristics are manifested as Figure 3 The Raman spectrum of -1 and 1602.10 cm -1 The two characteristic peaks of the hexagonal boron nitride flake 1 prove that the high-power excitation leads to the enrichment of carbon-related defects. At the same time, under laser excitation, the carbon-related defects in the hexagonal boron nitride flake 1 produce fluorescence. Figure 4 In the fluorescence spectrum, after the hexagonal boron nitride thin film 1 produces a large-scale quantum light source, a wide fluorescence peak in the range of about 550-800 nm appears, the luminescence peak of about 573.04 nm is the Raman peak of hexagonal boron nitride, and the luminescence peak with a peak value of 581.48 nm is the Raman peak of carbon-related defects. This proves that the present invention provides a large-scale quantum light source of hexagonal boron nitride carbon-related defect luminescence based on high-power continuous laser processing.

[0058] Figure 5 The large-scale quantum light source of the present invention is patterned fluorescence under laser excitation. After activating the large-scale quantum light source in a specific area on the hBN sheet with a high-power continuous laser, the movement of the high-precision three-dimensional displacement platform is controlled to generate a patterned fluorescence on the hBN sheet. Figure 5 The specific "SSS" area in the film is processed to achieve patterning of large-scale quantum light sources.

[0059] In the present invention, generally, the two-dimensional material hexagonal boron nitride flakes are obtained by mechanically peeling the hexagonal boron nitride crystals with Scotch tape, and the thickness is 5-50 nm. The laser wavelength is 500-532 nm, and the power is not less than 10 mW / μm 2 .

[0060] The above-mentioned specific implementation methods are used to explain the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects, characterized in that: The following steps are included: S1, peeling off the 2D hBN flakes; S2, transferring the two-dimensional hBN sheet prepared in step S1 to a PDMS sheet substrate; S3, transferring the two-dimensional hBN sheet to the silicon dioxide substrate through the PDMS sheet substrate; S4, using high-power density continuous laser to irradiate the two-dimensional hBN thin film. Through the excitation of high-power continuous laser, the energy of the incident photon is much greater than the potential barrier that the carbon-related defects need to overcome in the lattice migration, and the thermal effect in the hBN thin film is accumulated, and the thermal motion of carbon-related defects is intensified. The carbon-related defects originally uniformly distributed in the laser irradiation area are enriched under the action of high-power continuous laser, and combined in the laser irradiation area to form lower energy C2C N 、C2C B , C2 defect state, thus forming a quantum light source; S5, using a low-power laser to excite the hBN thin film quantum light source obtained in step S4, the quantum light source generates fluorescence, and the presence of carbon-enriched related defects is characterized by two new characteristic peaks appearing in the Raman spectrum; S6, moving the substrate sheet with the hBN thin sheet to control the movement of the area of ​​the hBN thin sheet irradiated by the laser, and realizing a customized patterned large-scale quantum light source on the hBN thin sheet; Among them, hBN is hexagonal boron nitride and PDMS is polydimethylsiloxane.

2. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects according to claim 1, characterized in that: In step S1, a two-dimensional hBN sheet is mechanically peeled off from a hexagonal boron nitride crystal using Scotch tape, wherein the thickness of the two-dimensional hBN sheet is 5-50 nm.

3. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects according to claim 1, characterized in that: In step S2, the hBN flakes obtained in step S1 are transferred to a PDMS flake substrate, and mechanically separated and transferred by utilizing the viscosity of the PDMS flake substrate.

4. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects according to claim 1, characterized in that: In step S3, the PDMS sheet base and the hBN sheet are attached to a silicon dioxide substrate, and heated at 80° C. for ten minutes to make the PDMS sheet base lose its stickiness and then peeled off, and the hBN sheet is transferred to the silicon dioxide substrate.

5. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects according to claim 1, characterized in that: In step S6, the movement of the substrate sheet with the hBN thin sheet is controlled by a high-precision electric three-dimensional displacement platform to control the movement of the laser processing area in step S4. The movement of the laser processing area is controlled by the three-dimensional displacement platform to realize a customized patterned large-scale quantum light source on the hBN thin sheet.

6. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects according to claim 1, characterized in that: The method further includes step S7, in which a low-power, large-spot continuous light laser is used for secondary excitation to observe the hBN thin-sheet patterned quantum light source obtained in step S6.

7. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects according to claim 6, characterized in that: In step S7, the patterned observation of the hBN thin film quantum light source is performed at a wavelength of 400-550 nm, a power of no more than 0.1 mW, and a spot area of ​​no less than 10 μm 2 under continuous laser excitation.

8. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects as claimed in claim 1, characterized in that: The laser wavelength irradiated to the hBN sheet and stimulated the carbon-related defect enrichment in step S4 is 500-550nm, and the power density is not less than 10 mW / μm 2 .

9. The method for large-scale preparation of patterned quantum light sources based on photoactivated carbon defects according to claim 1, characterized in that: In step S5, the laser wavelength of the quantum light source that excites the hBN sheet to produce fluorescence is 500-550 nm, and the power density is not higher than 0.1 mW / μm 2 ; The maximum range of the wavelength of the quantum light source for exciting the hBN thin slice is 550-800 nm; The two new characteristic peaks in the Raman spectrum are generated after carbon defect enrichment, with peak values ​​of about 1330 cm -1 and about 1602 cm -1 .

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