A method for preparing diamond rare earth europium color center particles

Abstract

This invention discloses a method for preparing diamond rare-earth europium (EEUR) color core particles, belonging to the field of non-metallic element materials. The method involves coating a europium oxide suspension onto a single polished silicon wafer, followed by microwave plasma chemical vapor deposition (CPCVD) to form EEUR color core particles. This method allows for the growth of EEUR color core particles on the surface of a diamond film. The absence of obvious traces of Eu₂O₃ nanoparticles on the surface of the EEUR color core particles indicates that the diamond implantation solution within the europium oxide particles rapidly forms the EEUR color core particles during CPCVD, resulting in the diamond core ultimately covering the europium oxide particles, thus forming a core-shell structure, i.e., the diamond rare-earth europium color core particles. The obtained EEUR color core particles are mostly irregularly shaped with a diameter of approximately 8 μm.

Description

Technical Field

[0001] This invention relates to the field of non-metallic element materials, and in particular to a method for preparing diamond rare earth europium color center particles. Background Technology

[0002] Diamond, with its high thermal conductivity, high electron and hole mobility, unparalleled hardness, biocompatibility, and other physical properties, is the material of choice for a wide range of applications and is considered a promising next-generation functional material. Diamond possesses numerous optically active defects (color centers), particularly vacancy-related and impurity-related defects. These color centers exhibit interesting optical and spin properties and can be synthesized into diamond nanoparticles, thin films, and single crystals through doping processes, which will drive the development of diamond-based materials in quantum applications.

[0003] Currently, the most studied color centers include: nitrogen vacancy centers (NV), Group IV vacancy centers (silicon vacancy center SiV, germanium vacancy center GeV, tin vacancy center SnV, and lead vacancy center PbV) and transition metal vacancy centers (titanium vacancy center TiV, chromium vacancy center CrV, and nickel vacancy center NiV).

[0004] Existing technologies, such as Chinese invention patent with announcement number CN117985710A, disclose a method for preparing diamond single NV color centers, single NV color center diamond and its application; and Chinese invention patent with announcement number CN110395727B, disclose a method for preparing color center diamond and color center diamond. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing diamond rare earth europium color center particles.

[0006] The technical solution adopted in this invention is as follows: This invention provides a method for preparing diamond rare earth europium color core particles, comprising: Step 1, cleaning a single polished silicon wafer sequentially with acetone, hydrofluoric acid, anhydrous ethanol, and deionized water to remove surface end caps and impurities; then, drying it with nitrogen gas for later use; followed by plasma cleaning; then, placing the single polished silicon wafer into a diamond crystal implantation solution for crystal implantation, and drying it with nitrogen gas after crystal implantation to obtain a crystal implantation substrate.

[0007] Step 2: A diamond film is prepared on the implanted substrate of Step 1 using microwave plasma chemical vapor deposition.

[0008] Step 3: Coat the diamond film prepared in step 2 with europium oxide suspension, and then heat and dry it; the europium oxide suspension is prepared by mixing Eu2O3 particles, dimethyl sulfoxide and nanodiamond colloidal solution.

[0009] Step 4: A microwave plasma chemical vapor deposition (IPD) device is used to perform a secondary deposition on the diamond film treated in Step 3 to form diamond rare earth europium color core particles; then, anhydrous ethanol is used to clean the particles to obtain the final product.

[0010] Furthermore, in step 1, the single polished silicon wafer is N-type, 100-phase, 20×20mm single crystal surface, and 500±10μm thick.

[0011] Furthermore, in step 1, the diamond implantation solution is prepared as follows: using an ultrasonic cleaner, 500 μl of nano-diamond colloidal solution and 50 ml of deionized water are ultrasonically mixed to obtain the diamond implantation solution; the ultrasonic cleaning temperature is set to 25℃, the ultrasonic frequency is set to 800 Hz, and the time is set to 60 min.

[0012] Further, the operation method of step 2 is as follows: the implanted substrate obtained in step 1 is placed in a microwave plasma chemical vapor deposition (MPCVD) apparatus; the conditions and parameters of the MPCVD apparatus are set as follows: pure gas is used as the precursor, the pure gas consists of hydrogen and methane, the purity of hydrogen is 99.9999%, and the purity of methane is 99.9995%; the methane concentration in the gas mixture accounts for 1% of the total gas flow rate, the total gas flow rate is 250 sccm, and the atmospheric leakage in the vacuum chamber does not exceed 0.01 sccm; the microwave power in the vacuum chamber is 1.2 kW, the pressure is 4.5 kPa, the temperature is 900±10℃, and the deposition time is 60 min, forming a diamond film on the implanted substrate.

[0013] Furthermore, in step 3, the amount of Eu2O3 particles used is 0.02g, with a particle size of 40nm; the amount of dimethyl sulfoxide solution used is 20ml; and the amount of nanodiamond colloidal solution used is 500μl.

[0014] Furthermore, in step 3, a spin coater is used to coat a diamond film with a suspension of 0.005 ml europium oxide. The spin coater parameters are set as follows: spin coat speed is 2000 rpm, acceleration is 100 rpm, and spin coat time is 60 s. Afterward, the coated diamond film is placed on a constant temperature heating stage for heating and drying for 10 min to dry the europium oxide onto the diamond film. The temperature of the constant temperature heating stage is set to 100℃.

[0015] Furthermore, in step 4, the operation method is as follows: The product prepared in step 3 is placed in the deposition chamber of a microwave plasma chemical vapor deposition (IPD) device. The conditions and parameters of the device are set as follows: Ultrapure gas is used as the precursor, and the components of the ultrapure gas are hydrogen and methane, with a hydrogen purity of 99.9999% and a methane purity of 99.9995%; the methane concentration in the ultrapure gas accounts for 1.2% of the total gas flow rate, and the total gas flow rate is 200 sccm; atmospheric leakage in the vacuum chamber does not exceed 0.01 sccm; the microwave power in the vacuum chamber is 1.2 kW, the pressure is 4.5 kPa, the temperature is 850 ± 10℃, and the deposition time is 2 h.

[0016] The beneficial effects of this invention are as follows: This invention provides a method for preparing diamond rare-earth europium color core particles. This method allows for the growth of diamond rare-earth europium color core particles on the surface of a diamond film. The absence of obvious traces of Eu₂O₃ nanoparticles on the surface of these color core particles indicates that the diamond implantation solution within the europium oxide particles rapidly forms the diamond rare-earth europium color core particles during chemical vapor deposition. This allows the diamond core to eventually cover the europium oxide particles themselves, thus forming a core-shell structure, i.e., the diamond rare-earth europium color core particles. The obtained diamond rare-earth europium color core particles are mostly irregularly shaped with a diameter of approximately 8 μm. Attached Figure Description

[0017] Figure 1 The diagram shows a flowchart of the preparation method of the present invention.

[0018] Figure 2 The image shown is an image of the surface morphology and thickness of the diamond film after processing in step 2 of Embodiment 1 of the present invention, detected using a scanning electron microscope; wherein, Figure 2 Figure a shows a scanning electron microscope (SEM) image of the diamond film prepared on the implanted substrate after step 2 of Example 1 of the present invention at a scale of 400 nm. Figure 2 Figure b shows a cross-sectional scanning electron microscope image of the diamond film prepared on the implanted substrate after step 2 of Embodiment 1 of the present invention at the 1 μm scale.

[0019] Figure 3 The image shown is an atomic force microscope image of the diamond film after treatment in step 2 of Embodiment 1 of the present invention.

[0020] Figure 4 This is a detection image obtained by using a confocal microscope combining Raman and fluorescence microscopy to detect the quality and fluorescence of a diamond film after the processing in step 2 of Embodiment 1 of the present invention; wherein, Figure 4 a is the Raman spectroscopy image of the diamond film after treatment in step 2 of Embodiment 1 of the present invention. Figure 4 b is a fluorescence detection image of the diamond film after treatment in step 2 of Embodiment 1 of the present invention.

[0021] Figure 5 The image shown is a scanning electron microscope (SEM) image after step 3 of Embodiment 1 of the present invention. Wherein, Figure 5 a is a scanning electron microscope image at the 50 μm scale; Figure 5 b is a scanning electron microscope image at the 10 μm scale; Figure 5 c is a scanning electron microscope image at the 5μm scale; Figure 5 d is a scanning electron microscope image at the 2μm scale.

[0022] Figure 6 This is a detection image obtained by using a scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) to detect the elemental distribution on a diamond film after step 3 of Embodiment 1 of the present invention; wherein, Figure 6 a is a scanning electron microscope image at the 2μm scale after processing in step 3 of embodiment 1 of the present invention. Figure 6 b is Figure 6 The scanning electron microscope energy dispersive spectroscopy (EDS) image of region a, where red represents carbon and green represents eu. Figure 6 c is Figure 6 Scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS) image of carbon element distribution in region b. Figure 6 d is Figure 6 The distribution of Eu element in region b is shown by scanning electron microscopy and energy dispersive spectroscopy.

[0023] Figure 7 This is a detection image obtained by using a scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) to detect single (large) irregular aggregates of europium oxide attached to the diamond film in step 3 of Example 1; wherein, Figure 7 a shows a scanning electron microscope image of an irregular aggregate of approximately 5×5 micrometers; Figure 7 b shows Figure 7 a. Scanning electron microscopy energy dispersive spectroscopy (EDS) image of the 3×3.5μm region with a green border. Figure 7 In b, red represents element C.

[0024] Figure 8 What is shown is Figure 7 Fluorescence confocal microscopy image of irregular aggregates in a.

[0025] Figure 9 The image shown is a scanning electron microscope (SEM) image of the diamond rare-earth europium color center particles prepared in step 4 of Example 1 of this invention. Wherein, Figure 9 a is a scanning electron microscope image at the 50 μm scale; Figure 9 b is a scanning electron microscope image at the 10 μm scale; Figure 9 c is a scanning electron microscope image at the 5μm scale; Figure 9 d is a scanning electron microscope image at the 2μm scale.

[0026] Figure 10The image shown is a scanning electron microscope (SEM) image of the diamond rare-earth europium color center particles prepared in step 4 of Example 1 of this invention; wherein, Figure 10 a is the energy dispersive spectroscopy (EDS) image of rare earth europium color center particles in diamond, where red represents carbon (C) and green represents eu. Figure 10 b is Figure 10 Scanning electron microscope energy dispersive spectroscopy (EDS) image of C element distribution in region a; Figure 10 c is Figure 10 Scanning electron microscope energy dispersive spectroscopy (SEM) image of Eu element distribution in region a; Figure 10 d is Figure 10 Scanning electron microscope image of diamond rare earth europium color center particles in region a. Figure 10 Five sites were marked in d; Figure 10 e is Figure 10 C / Eu percentage detection map for 5 sites in region d.

[0027] Figure 11 The image shown is an X-ray photoelectron spectroscopy (XPS) image of the diamond rare-earth europium color center particles prepared in Example 1 of this invention; wherein, Figure 11 a is the 4d energy XPS image of Eu. Figure 11 b is the 3d energy XPS image of Eu.

[0028] Figure 12 The image shown is a Raman confocal microscope image of the diamond rare earth europium color center particles prepared in Example 1 of this invention.

[0029] Figure 13 The image shown is a fluorescence confocal microscope image of the diamond rare earth europium color center particles prepared in Example 1 of this invention.

[0030] Figure 14 This is a fluorescence confocal microscope image of diamond rare earth europium particles prepared by prior art 1.

[0031] Figure 15 The image shown is a scanning electron microscope image of the diamond rare earth europium color center particles prepared in Comparative Example 1.1 of the present invention.

[0032] Figure 16 The image shown is a detection diagram of defective particles obtained in Comparative Example 1.2 of the present invention; wherein, Figure 16 The image shown is a detection diagram of defective particles obtained in Comparative Example 1.2 of the present invention; wherein, Figure 16 Figure a shows an energy dispersive spectroscopy (EDS) image of a defective particle obtained in Comparative Example 1.2 of the present invention; red represents carbon (C) and green represents eu. Figure 16 b is Figure 16 Scanning electron microscope energy dispersive spectroscopy (EDS) image of C element distribution in region a; Figure 16 c is Figure 16 Scanning electron microscope energy dispersive spectroscopy (SEM) image of Eu element distribution in region a; Figure 16 d is Figure 16 Scanning electron microscopy (SEM) image of diamond rare-earth europium color centers in region a at a 2 μm scale. Figure 16 Three sites are marked in d; Figure 16 e is Figure 16 C / Eu percentage detection map for 3 sites in region d. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The main performance indicators and sources of the main raw materials and reagents used in this invention are shown in Table 1 below.

[0035] Table 1. Summary of the main performance indicators and sources of the main raw materials and reagents of this invention

[0036] Example 1: This application provides a method for preparing diamond rare earth europium color core particles, including the following steps.

[0037] Step 1: The single-polished silicon wafer is cleaned sequentially with acetone, hydrofluoric acid, anhydrous ethanol, and deionized water to remove surface end caps and impurities; then, it is dried with nitrogen gas for later use; next, plasma cleaning is performed; then, the single-polished silicon wafer is placed in diamond implantation solution for crystal implantation, and after implantation, it is dried with nitrogen gas to obtain the implanted substrate. The specific operation is as follows.

[0038] In this embodiment, an ultrasonic cleaner was used to clean the single-polished silicon wafer. The cleaning agents used were acetone, hydrofluoric acid, anhydrous ethanol, and deionized water in sequence. The specific operation was as follows: the ultrasonic cleaning temperature was set to 25°C, and the ultrasonic frequency was set to 800Hz. First, the single-polished silicon wafer was cleaned in acetone (30 ml, analytical grade) for 10 minutes. Then, it was cleaned in 55% hydrofluoric acid (30 ml) for 10 minutes to remove surface end caps. Next, it was cleaned in anhydrous ethanol (30 ml, analytical grade) for 10 minutes to remove surface impurities. Finally, it was cleaned in deionized water (30 ml) for 10 minutes. Afterward, it was dried with nitrogen gas for later use.

[0039] The dried single-polished silicon wafers are placed in a plasma cleaner (model CY-PC40k-2L-SS) for secondary cleaning. The surface of the single-polished silicon wafer is bombarded with plasma to thoroughly remove residual impurities. Ar is used as the protective gas in the plasma cleaner, and the cleaning time is 10 minutes.

[0040] The diamond implantation solution is prepared as follows: Using an ultrasonic cleaner, 500 μl of nanodiamond colloidal solution and 50 ml of deionized water are ultrasonically mixed to obtain the diamond implantation solution. The ultrasonic cleaning temperature is set to 25℃, the ultrasonic frequency to 800 Hz, and the time to 60 min.

[0041] In an ultrasonic cleaner, a single-polished silicon wafer is immersed in a diamond implantation solution for crystal implantation. The ultrasonic cleaning temperature is 25℃, the ultrasonic frequency is 800Hz, and the time is 40 minutes. After crystal implantation, the surface of the single-polished silicon wafer is covered with nano-diamond particles. Then, nitrogen gas is used for drying to prevent secondary contamination of the implanted single-polished silicon wafer by air impurities, thus obtaining a implanted substrate.

[0042] Step 2: A diamond film is prepared on the implanted substrate from Step 1 using a microwave plasma chemical vapor deposition (IPD) system. The specific procedures are as follows.

[0043] The implanted substrate obtained in step 1 was placed in a microwave plasma chemical vapor deposition (MPCVD) apparatus. The conditions and parameters of the MPCVD apparatus were set as follows: pure gas was used as the precursor, consisting of hydrogen and methane, with hydrogen purity of 99.9999% and methane purity of 99.9995%; the methane concentration in the gas mixture accounted for 1% of the total gas flow rate, the total gas flow rate was 250 sccm, and atmospheric leakage in the vacuum chamber did not exceed 0.01 sccm. The microwave power in the vacuum chamber was 1.2 kW, the pressure was 4.5 kPa, the temperature was 900 ± 10 °C, and the deposition time was 60 min, forming a diamond film on the implanted substrate.

[0044] Furthermore, this invention employs scanning electron microscopy to inspect the surface morphology and thickness of the diamond film. For example... Figure 2 The image shown is an image of the surface morphology and thickness of the diamond film after processing in step 2 of Embodiment 1 of the present invention, detected using a scanning electron microscope; wherein, Figure 2 Figure a shows a scanning electron microscope (SEM) image of the diamond film prepared on the implanted substrate after step 2 of Example 1 of the present invention at a scale of 400 nm. Figure 2 Figure b shows a cross-sectional scanning electron microscope (SEM) image at the 1 μm scale of the diamond film prepared on the implanted substrate after step 2 of Example 1 of this invention. Figure 2 As can be seen from a, the diamond film consists of a single layer of uniform and dense nanodiamond particles. From... Figure 2As can be seen from b, the thickness of the diamond film is approximately 0.4 μm.

[0045] Furthermore, this invention employs atomic force microscopy to inspect the surface quality of the diamond film. For example... Figure 3 The image shown is an atomic force microscope (AFM) image of the diamond film after treatment in step 2 of Embodiment 1 of the present invention. Figure 3 As can be seen, the average roughness Ra of the diamond film is 23.7 nm, which indicates that the roughness is very low, which can increase the contact area between the film surface and the europium oxide suspension and enhance the adhesion of the europium oxide suspension.

[0046] Furthermore, this invention employs a Raman and fluorescence confocal microscope to detect the quality and fluorescence of the diamond film. For example... Figure 4 This is a detection image obtained by using a confocal microscope combining Raman and fluorescence microscopy to detect the quality and fluorescence of a diamond film after the processing in step 2 of Embodiment 1 of the present invention; wherein, Figure 4 a is the Raman spectroscopy image of the diamond film after treatment in step 2 of Embodiment 1 of the present invention. Figure 4 b is a fluorescence detection image of the diamond film after treatment in step 2 of Embodiment 1 of the present invention. Figure 4 The curves marked in section a are as follows: the black curve represents the basic data, the light blue and red curves represent the trans-polyacetylene (TPA) related vibration peak, the dark blue curve represents diamond, the magenta curve represents the diamond related peak (Disorder band, D band), the light green and yellow curves represent the graphite band (G band), and the gray curve represents the fitted data.

[0047] from Figure 4 As can be seen from a, the diamond peak is 1333cm. -1 At 1100cm, the peak intensity is 1369; at 1100cm -1 and 1200cm -1 The peak value at 1340 cm⁻¹ is associated with the vibrational mode of trans-polyacetylene (TPA), which is attributed to the in-plane bending mode and the tensile vibrational mode of CC,C=C. -1 The nearby D peak is due to the ring-shaped "breathing" vibrational mode of the carbon sp2 phase, while at 1540 cm⁻¹... -1 With 1750cm -1 The nearby G peak is generated by the mixed vibration mode of the sp2 phase. The diamond peak is significantly higher than the graphite peak, proving that the film has a large amount of diamond phase.

[0048] from Figure 4 b shows that there are diamond-graphite characteristic peaks and NV near 580nm. 0The appearance of the color center fluorescence peak is due to NV - The color center has a relatively weak light intensity, so no characteristic peaks appear; there is a relatively broad NV at 638 nm. - Colored phonon sideband; diamond SiV at 738nm - A fluorescence peak appeared with an intensity of 8819.43.

[0049] Step 3: Coat the diamond film prepared in step 2 with europium oxide suspension, and then heat and dry it; the europium oxide suspension is prepared by mixing Eu2O3 particles, dimethyl sulfoxide and nanodiamond colloidal solution.

[0050] In this embodiment, the amount of Eu2O3 particles used was 0.02 g, with a particle size of 40 nm; the amount of dimethyl sulfoxide solution used was 20 ml; and the amount of nanodiamond colloidal solution used was 500 μl. The Eu2O3 particles, dimethyl sulfoxide solution, and diamond colloidal solution were placed in a 50 ml beaker and ultrasonically mixed to obtain a europium oxide suspension. The ultrasonic cleaning temperature was set to 25°C, the ultrasonic frequency to 800 Hz, and the time to 600 min.

[0051] Europium oxide suspension was coated onto the diamond film prepared in step 2. The specific operation method is as follows: A spin coater (model CY-SP4, Zhengzhou Chengyue Scientific Instruments Co., Ltd.) was used to coat 0.005 ml of europium oxide suspension onto the diamond film. In this embodiment, the spin coater parameters were set as follows: spin coat speed of 2000 rpm, acceleration of 100 rpm, and spin coat time of 60 s. Afterward, the coated diamond film was placed on a constant temperature heating stage (model HPA-2020, Wenzhou Hanbang Electronics Co., Ltd.) for heating and drying for 10 min to dry the europium oxide onto the diamond film. The temperature of the constant temperature heating stage was set to 100℃.

[0052] Furthermore, this invention employs scanning electron microscopy to detect the distribution morphology of Eu2O3 nanoparticles on the surface of the diamond film. For example... Figure 5 The image shown is a scanning electron microscope (SEM) image after step 3 of Embodiment 1 of the present invention. Wherein, Figure 5 a is a scanning electron microscope image at the 50 μm scale; Figure 5 b is a scanning electron microscope image at the 10 μm scale; Figure 5 c is a scanning electron microscope image at the 5μm scale; Figure 5 d is a scanning electron microscope image at the 2μm scale.

[0053] from Figure 5 As can be seen from a, the Eu2O3 nanoparticles are uniformly dispersed on the diamond film, without large-area aggregation; from Figure 5 b to Figure 5As can be seen from d, Eu2O3 nanoparticles exhibit a micron-sized aggregated state, typically combining into aggregates of about 1-4 μm, with no nano-aggregates observed.

[0054] Furthermore, Figure 5 Nanoparticles in diamond films are difficult to observe clearly. To more clearly observe the dispersion of these nanoparticles, this invention uses a scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) to detect the elemental distribution on the diamond film. For example... Figure 6 This is a detection image obtained by using a scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) to detect the elemental distribution on a diamond film after step 3 of Embodiment 1 of the present invention; wherein, Figure 6 a is a scanning electron microscope image at the 2μm scale after processing in step 3 of embodiment 1 of the present invention. Figure 6 b is Figure 6 The scanning electron microscope energy dispersive spectroscopy (EDS) image of region a, where red represents carbon and green represents eu. Figure 6 c is Figure 6 Scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS) image of carbon element distribution in region b. Figure 6 d is Figure 6 The distribution of Eu element in region b is shown by scanning electron microscopy and energy dispersive spectroscopy.

[0055] from Figure 6 a to Figure 6 As can be seen in d, the small agglomerates formed by Eu2O3 nanoparticles appear as small, dark green dots, proving that Eu2O3 nanoparticles are uniformly dispersed on the diamond film in the form of small agglomerates.

[0056] Furthermore, to more clearly observe the dispersion of diamond nanoparticles within the Eu2O3 aggregates, this invention employs scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) to detect the individual (large) irregular europium oxide aggregates attached to the diamond film in step 3 of Example 1. For example... Figure 7 This is a detection image obtained by using a scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) to detect single (large) irregular aggregates of europium oxide attached to the diamond film in step 3 of Example 1; wherein, Figure 7 a shows a scanning electron microscope image of an irregular aggregate of approximately 5×5 micrometers; Figure 7 b shows Figure 7 a. Scanning electron microscopy energy dispersive spectroscopy (EDS) image of the 3×3.5μm region with a green border. Figure 7 In b, red represents element C.

[0057] from Figure 7 As can be seen in b, there is a distribution of red C elements on the white aggregates, indicating that the irregular europium oxide aggregates are a mixture of europium oxide particles and nanodiamond particles.

[0058] Furthermore, this invention employs fluorescence-coupled confocal microscopy to... Figure 7 Irregular aggregates in a were detected. For example... Figure 8 What is shown is Figure 7 Fluorescence confocal microscopy image of irregular aggregates in image a. From Figure 8 As can be seen, the fluorescence spectrum contains 5 lines related to 5 D0- 7 F i The spectral lines related to the transitions (i = 0-4) are respectively for ~580nm. 5 D0- 7 The F0 transition has an intensity of 1259.05; ~590nm corresponds to 5 D0- 7 The F1 transition has an intensity of 1296.88; ~610nm corresponds to 5 D0- 7 The F2 transition has an intensity of 10107.20; ~655nm corresponds to 5 D0- 7 The F3 transition has an intensity of 402.19; the ~690nm range corresponds to... 5 D0- 7 The F4 transition has an intensity of 1025.71, indicating that the nano-Eu2O3 particles still exhibit good luminescent properties after homogenization.

[0059] Step 4: A microwave plasma chemical vapor deposition (IPD) system is used to perform a secondary deposition on the diamond film treated in Step 3 to form diamond rare earth europium color core particles; then, the particles are cleaned with anhydrous ethanol to obtain the final product. The specific operation is as follows.

[0060] The product prepared in step 3 was placed in the deposition chamber of a microwave plasma chemical vapor deposition (IPD) apparatus. The apparatus conditions and parameters were set as follows: an ultrapure gas was used as the precursor, consisting of hydrogen and methane, with hydrogen purity of 99.9999% and methane purity of 99.9995%; the methane concentration in the ultrapure gas accounted for 1.2% of the total gas flow rate, and the total gas flow rate was 200 sccm; atmospheric leakage in the vacuum chamber did not exceed 0.01 sccm; the microwave power in the vacuum chamber was 1.2 kW, the pressure was 4.5 kPa, the temperature was 850 ± 10 °C, and the deposition time was 2 h.

[0061] The diamond rare earth europium color center particles formed after deposition were placed in a glass weighing bottle containing 30 ml of anhydrous ethanol for cleaning, and ultrasonic cleaning was performed using an ultrasonic cleaner; during the cleaning process, the temperature was 25℃, the ultrasonic frequency was 800 Hz, and the cleaning time was 5 min.

[0062] To observe the growth of rare-earth europium color centers in diamond, this invention employs scanning electron microscopy to detect these centers on the diamond film. For example... Figure 9 The image shown is a scanning electron microscope (SEM) image of the diamond rare-earth europium color center particles prepared in step 4 of Example 1 of this invention. Wherein, Figure 9 a is a scanning electron microscope image at the 50 μm scale; Figure 9 b is a scanning electron microscope image at the 10 μm scale; Figure 9 c is a scanning electron microscope image at the 5μm scale; Figure 9 d is a scanning electron microscope image at the 2μm scale.

[0063] from Figure 9 As can be seen from a to 9d, numerous diamond rare-earth europium (EEH) color centers of varying sizes grow on the surface of the diamond film. These EEH color centers are irregularly shaped, ranging from approximately 1 to 10 μm, with most being around 8 μm in size. The absence of obvious traces of Eu₂O₃ nanoparticles on the surface of these EEH color centers indicates that the diamond implantation solution within the europium oxide particles rapidly forms EEH color centers during chemical vapor deposition. This allows the diamond core to eventually cover the europium oxide particles, creating a core-shell structure, i.e., the diamond rare-earth europium color centers.

[0064] Furthermore, in order to observe the distribution of diamond and rare earth europium in the diamond rare earth europium color center particles, this invention uses a scanning electron microscope energy dispersive spectroscopy (EDS) instrument to detect the rare earth europium color center particles on the diamond film.

[0065] like Figure 10 The image shown is a scanning electron microscope (SEM) image of the diamond rare-earth europium color center particles prepared in step 4 of Example 1 of this invention; wherein, Figure 10 a is the energy dispersive spectroscopy (EDS) image of rare earth europium color center particles in diamond, where red represents carbon (C) and green represents eu. Figure 10 b is Figure 10 Scanning electron microscope energy dispersive spectroscopy (EDS) image of C element distribution in region a; Figure 10 c is Figure 10 Scanning electron microscope energy dispersive spectroscopy (SEM) image of Eu element distribution in region a; Figure 10 d is Figure 10 Scanning electron microscope image of diamond rare earth europium color center particles in region a. Figure 10 Five sites were marked in d; Figure 10 e is Figure 10 C / Eu percentage detection map for 5 sites in region d.

[0066] from Figure 10 a to Figure 10As can be seen from image e, the irregular particle size of a single diamond Eu color center is approximately 7.8 × 7.8 μm. The green light spot is surrounded by a red light spot, indicating that the diamond particle contains Eu element. The average content of europium element at sites 1-5 is 4.06%, with the highest content at the middle 3 sites and relatively lower content at other sites. This indicates that the edge part of the europium element is diamond grown around the Eu2O3 aggregate, confirming the incorporation of Eu2O3 nanoparticles into the diamond.

[0067] Furthermore, this invention employs X-ray photoelectron spectroscopy to detect the rare-earth europium color center particles in diamond prepared in Example 1. For example... Figure 11 The image shown is an X-ray photoelectron spectroscopy (XPS) image of the diamond rare-earth europium color center particles prepared in Example 1 of this invention; wherein, Figure 11 a is the 4d energy XPS image of Eu. Figure 11 b is the 3d energy XPS image of Eu.

[0068] from Figure 11 As can be seen from a, the 4d binding energies of Eu are Eu... 2+ 4d 5 / 2 (128.4 e V), Eu 2+ 4d 3 / 2 (134.2 e V), Eu 3+ 4d 5 / 2 (136.7 e V) and Eu 3+ 4d 3 / 2 (142.3 e V), none of them have characteristic peaks. From Figure 11 As can be seen from b, the 3d binding energies of Eu are respectively Eu 2+ 3D 5 / 2 (1126.3 e V), Eu 2+ 3D 3 / 2 (1156.2 e V), Eu 3+ 3D 5 / 2 (1136.5 e V) and Eu 3+ 3D 3 / 2 (1166.1 e V) has no characteristic peaks; this indicates that the surface of the rare earth europium color center particles in diamond does not have exposed Eu2O3 nanoparticles, but is in a diamond-encapsulated state, which further confirms that Eu2O3 nanoparticles are incorporated into diamond.

[0069] Furthermore, this invention employs Raman confocal microscopy to detect the rare-earth europium color centers in diamond prepared in Example 1. For example... Figure 12 The image shown is a Raman confocal microscope image of the diamond rare earth europium color center particles prepared in Example 1 of this invention. Figure 12The curves marked in the middle are as follows: the black curve represents the basic data, the light blue and red curves represent the trans-polyacetylene (TPA) related vibration peak, the dark blue curve represents diamond, the magenta curve represents the diamond related peak (Disorder band, D band), the light green and yellow curves represent the graphite band (G band), and the gray curve represents the fitted data.

[0070] from Figure 12 As can be seen from this, the diamond Raman peak is at 1333cm. -1 At 1100cm -1 and 1200cm -1 The peak value at 1340 cm⁻¹ is associated with the vibrational mode of trans-polyacetylene (TPA), which is attributed to the in-plane bending mode and the tensile vibrational mode of CC,C=C. -1 The nearby D peak is due to the cyclic "breathing" vibrational mode of the carbon sp2 phase at 1340 cm⁻¹. -1 The nearby D peak is due to the ring-shaped "breathing" vibrational mode of the carbon sp2 phase, while at 1540 cm⁻¹... -1 With 1750cm -1 The nearby G peak is generated by the mixed vibrational mode of the sp2 phase. The diamond peak and graphite peak have almost identical intensities, indicating that the diamond grain is predominantly composed of the diamond phase. Figure 4 A comparative study revealed that the formation of rare-earth europium color centers in diamond promoted the formation of the graphite phase, but reduced the quality of the diamond.

[0071] Furthermore, this invention employs fluorescence confocal microscopy to detect the rare-earth europium color centers in diamond prepared in Example 1. For example... Figure 13 The image shown is a fluorescence confocal microscope image of the diamond rare-earth europium color center particles prepared in Example 1 of this invention. From... Figure 13 As can be seen, there is a narrow emission peak for Eu at approximately 611 nm, and for diamond SiV at 738 nm. - The color center has strong emission peaks, with the Eu emission peak having a full width at half maximum (FWHM) of 0.8 nm and an intensity of SiV. - 1.4 times that of the color center; with Figure 4 Comparison with b revealed an additional Eu emission peak at 611 nm, indicating that Eu₂O₃ nanoparticles grew into diamond and formed diamond rare-earth europium color centers, proving the successful preparation of diamond rare-earth europium color center particles. Figure 8The comparison revealed that the intensity of the Eu emission peak at 611 nm was lower than that of the previous peak, and the other emission peaks were weakened or even absent. This is because the plasma environment during the deposition of diamond using microwave plasma chemical vapor deposition equipment caused partial degradation of the Eu2O3 nanoparticles, resulting in a decrease in emission intensity.

[0072] The present invention is compared with a previously disclosed technology as follows: The prior art 1, the reference is [1] Sedov V, Kuznetsov S, Martyanov A, et al. Diamond deposition on non-diamond microparticles: Toward the development of core-shell optical materials[J]. Surfaces and Interfaces, 2025, 64106479-106479.

[0073] The prior art uses a commercially available anhydrous EuF3 reagent (Ventron GMBH) spin-coated onto a (100) oriented silicon (Si) substrate and employs a microwave plasma chemical vapor deposition device to prepare diamond rare earth europium particles.

[0074] Figure 14 The image shows a fluorescence confocal microscope image of the diamond rare earth europium particles prepared by the prior art 1; in the image, the blue line at the top represents the diamond rare earth europium color center particles grown on the Si substrate.

[0075] from Figure 14 As can be seen, there is a weak Eu emission peak at 611.7 nm and a significant SiV emission peak at 738 nm. - The color center emission peak, due to SiV - The color center emitted a very strong light peak, so the upper part was truncated; (Comprehensive comparison) Figure 14 and Figure 13 It was discovered that diamond SiV at 738 nm... - Based on the color center emission peak, this invention Figure 13 The luminescence intensity of the europium diamond color center is SiV. - 1.4 times that of the color heart, and Figure 14 Although no precise numerical value was given for the luminescence intensity of the europium diamond color center, it was significantly lower than that of SiV. - The luminescence intensity of the color center indicates that the diamond rare earth europium color center particles of the present invention have better luminescence intensity.

[0076] In single-variable experiment 1, this invention further investigated the effect of using different amounts of nanodiamond colloidal solution in step 3 of Example 1 on the product of this invention. Below are two comparative examples, namely Comparative Example 1.1 and Comparative Example 1.2.

[0077] Comparative Example 1.1. Based on Example 1, only the preparation method of europium oxide suspension was changed. Specifically, when preparing europium oxide suspension, the amount of Eu2O3 particles was 0.02g; the amount of dimethyl sulfoxide solution was 20ml; and the amount of nanodiamond colloidal solution was 0μl.

[0078] like Figure 15 The image shown is a scanning electron microscope (SEM) image of the diamond rare-earth europium color center particles prepared in Comparative Example 1.1 of this invention. From... Figure 15 As can be seen, in Comparative Example 1.1, very few diamond rare earth europium color centers were formed after 2 hours of deposition; most were micro / nano Eu2O3 aggregates after etching. Figure 15 (marked within the red circle).

[0079] Comparative Example 1.2. Based on Example 1, only the preparation method of europium oxide suspension was changed. Specifically, when preparing europium oxide suspension, the amount of Eu2O3 particles was 0.02g; the amount of dimethyl sulfoxide solution was 20ml; and the amount of nanodiamond colloidal solution was 1000μl.

[0080] The diamond rare earth europium color center particles prepared in Comparative Example 1.2 also contain the diamond rare earth europium color center particles of Example 1, but they contain one defective particle. This invention selects a representative monomer from this defective particle for testing.

[0081] like Figure 16 The image shown is a detection diagram of defective particles obtained in Comparative Example 1.2 of the present invention; wherein, Figure 16 Figure a shows an energy dispersive spectroscopy (EDS) image of a defective particle obtained in Comparative Example 1.2 of the present invention; red represents carbon (C) and green represents eu. Figure 16 b is Figure 16 Scanning electron microscope energy dispersive spectroscopy (EDS) image of C element distribution in region a; Figure 16 c is Figure 16 Scanning electron microscope energy dispersive spectroscopy (SEM) image of Eu element distribution in region a; Figure 16 d is Figure 16 Scanning electron microscopy (SEM) image of diamond rare-earth europium color centers in region a at a 2 μm scale. Figure 16 Three sites are marked in d; Figure 16 e is Figure 16 C / Eu percentage detection map for 3 sites in region d.

[0082] from Figure 16 As can be seen from a to 16d, the first type of defective particles obtained in Comparative Example 1.2 are irregularly shaped, with a particle size of 3μm, an Eu content percentage of 0%, and a rare earth content of zero, which are diamond particles; this indicates that when the nanodiamond colloidal solution is increased to 1000μl, diamond particles will be produced.

[0083] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for preparing diamond rare earth europium color core particles, characterized in that, include: Step 1: Clean the single-polished silicon wafer sequentially with acetone, hydrofluoric acid, anhydrous ethanol, and deionized water to remove surface end caps and impurities; then, dry it with nitrogen gas for later use; then perform plasma cleaning; next, place the single-polished silicon wafer into diamond implantation solution for crystal implantation, and dry it with nitrogen gas after implantation to obtain the implanted substrate. Step 2: Prepare a diamond film on the implanted substrate of Step 1 using microwave plasma chemical vapor deposition. Step 3: Coat the diamond film prepared in step 2 with europium oxide suspension, and then heat and dry it; the europium oxide suspension is prepared by mixing Eu2O3 particles, dimethyl sulfoxide and nanodiamond colloidal solution; Step 4: A microwave plasma chemical vapor deposition (IPD) device is used to perform a secondary deposition on the diamond film treated in Step 3 to form diamond rare earth europium color core particles; then, anhydrous ethanol is used to clean the particles to obtain the final product.

2. The method for preparing diamond rare earth europium color core particles according to claim 1, characterized in that, In step 1, the single polished silicon wafer is N-type, 100 crystal phase, 20×20mm single crystal surface, and 500±10μm thick.

3. The method for preparing diamond rare earth europium color core particles according to claim 1, characterized in that, In step 1, the diamond implantation solution is prepared as follows: using an ultrasonic cleaner, 500 μl of nano diamond colloidal solution and 50 ml of deionized water are ultrasonically mixed to obtain the diamond implantation solution; the ultrasonic cleaning temperature is set to 25℃, the ultrasonic frequency is set to 800 Hz, and the time is set to 60 min.

4. The method for preparing diamond rare earth europium color center particles according to claim 1, characterized in that, The operation method for step 2 is as follows: The implanted substrate obtained in step 1 is placed in a microwave plasma chemical vapor deposition (MPCVD) apparatus. The conditions and parameters of the MPCVD apparatus are set as follows: pure gas is used as the precursor, and the pure gas consists of hydrogen and methane, with a hydrogen purity of 99.9999% and a methane purity of 99.9995%; the methane concentration in the gas mixture accounts for 1% of the total gas flow rate, the total gas flow rate is 250 sccm, and atmospheric leakage in the vacuum chamber does not exceed 0.01 sccm; the microwave power in the vacuum chamber is 1.2 kW, the pressure is 4.5 kPa, the temperature is 900 ± 10℃, and the deposition time is 60 min, forming a diamond film on the implanted substrate.

5. The method for preparing diamond rare earth europium color core particles according to claim 1, characterized in that, In step 3, the amount of Eu2O3 particles used is 0.02g, with a particle size of 40nm; the amount of dimethyl sulfoxide solution used is 20ml; and the amount of nanodiamond colloidal solution used is 500μl.

6. The method for preparing diamond rare earth europium color center particles according to claim 1, characterized in that, In step 3, a spin coater was used to coat a diamond film with a suspension of 0.005 ml europium oxide. The spin coater parameters were set as follows: spin coat speed of 2000 rpm, acceleration of 100 rpm, and spin coat time of 60 s. Afterward, the coated diamond film was placed on a constant temperature heating stage and heated and dried for 10 min to dry the europium oxide onto the diamond film. The temperature of the constant temperature heating stage was set to 100℃.

7. The method for preparing diamond rare earth europium color core particles according to claim 1, characterized in that, In step 4, the operation method is as follows: The product prepared in step 3 is placed in the deposition chamber of a microwave plasma chemical vapor deposition (IPV) device. The conditions and parameters of the device are set as follows: Ultrapure gas is used as the precursor, and the components of the ultrapure gas are hydrogen and methane, with a hydrogen purity of 99.9999% and a methane purity of 99.9995%; the methane concentration in the ultrapure gas accounts for 1.2% of the total gas flow rate, and the total gas flow rate is 200 sccm; atmospheric leakage in the vacuum chamber does not exceed 0.01 sccm; the microwave power in the vacuum chamber is 1.2 kW, the pressure is 4.5 kPa, the temperature is 850 ± 10℃, and the deposition time is 2 h.

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