Method for producing si-v color centers in diamond

Abstract

A method for preparing Si-V color centers in diamond, by placing a treated single crystal diamond seed in the center of a concentric silicon wafer, so that during growth the H plasma etches the Si-containing solid and releases Si atoms into the plasma atmosphere, thereby incorporating Si atoms into the diamond film to obtain Si-V color centers. In addition, there is the generation of polycrystalline diamond on the concentric silicon wafer, which also contains Si-V color centers; through this method, for the first time, the simultaneous growth of single crystal diamond and polycrystalline diamond containing Si-V color centers is realized, and secondly, by changing the concentration of methane in the growth atmosphere, the concentration of Si-V color centers in single crystal diamond can be effectively controlled, because the increase of methane concentration leads to a higher growth rate, which can enhance the diffusion of silicon to the diamond lattice, and also increase the concentration of defects, so that the combination of Si and holes is more.

Description

Technical Field

[0001] This invention patent relates to the field of novel color center preparation, specifically to a method for preparing Si-V color centers based on solid-doped diamond. Background Technology

[0002] Diamond luminescent centers possess superior properties such as high quantum efficiency, minimal photobleaching, and flicker-free operation, making them increasingly promising in fields such as quantum information processing, optoelectronics, and biomarking. Of the more than 500 diamond luminescent centers discovered to date, the nitrogen-vacancy center is the most widely studied, with its zero-phonon line located in the visible light band at room temperature (NV). 0 575 nm, NV – The phonon sidebands are relatively wide (approximately 100 nm). In recent years, negatively charged silicon vacancy centers have attracted increasing attention from researchers. A silicon vacancy center consists of a silicon atom and two adjacent lattice vacancies. Its zero-phonon line is located in the infrared band (around 738 nm), and its emission peak width at room temperature (one phonon sideband on each side of the zero-phonon line) is around 5 nm, decreasing to as low as 0.7 nm. Approximately 70% of its photons are concentrated at the zero-phonon line. In fields such as biofluorescence labeling, compared to nitrogen vacancy centers, the properties of silicon vacancy centers make their excitation fluorescence (signal) easier to observe. They exhibit weaker light absorption by biological materials and less autofluorescence (noise) caused by ambient visible light. Therefore, silicon vacancy center luminescence offers advantages such as higher image acquisition fidelity and spatial resolution.

[0003] Currently, there are two main methods for preparing diamond Si-V color centers: ion implantation and in-situ doping via chemical vapor deposition. A few studies also mention high-temperature, high-pressure methods. Ion implantation primarily involves using high-energy Si... 2+Bombarding diamond implants Si ions into the diamond lattice to form Si-V color centers. This method is mainly used to prepare Si-V color center single-photon sources, meeting the requirements of narrow phonon sidebands and short excited-state lifetimes. However, high-flux or high-energy ion beams can damage the diamond lattice, leading to nonradiative transitions and a significant decrease in the luminescence efficiency of Si-V color centers. With the rapid development of CVD technology, CVD can epitaxially grow high-quality single-crystal or polycrystalline diamond films, and the doping concentration and film microstructure can be effectively controlled, making in-situ chemical vapor deposition (CVD) doping a common method for preparing diamond Si-V color centers. CVD in-situ doping mainly includes Si-containing solid precursors (such as Si, SiC, or SiO2) and gaseous precursors (such as SiH4 or Si2H6). During the growth process, H plasma etches the Si-containing solid and releases Si atoms into the plasma atmosphere, enabling the preparation of individual diamond Si-V color centers. Recently, there have also been reports on the preparation of nanodiamond Si-V color centers using the high-temperature, high-pressure method. Summary of the Invention

[0004] This invention patent provides a method that can effectively control the concentration of Si-V color centers in single-crystal diamond while simultaneously achieving the growth of polycrystalline diamond and the preparation of Si-V color centers.

[0005] In order to effectively control the concentration of Si-V color centers in single-crystal diamond, the technical solution adopted in this invention is: a method for preparing Si-V color centers in diamond, comprising the following steps;

[0006] 1) Select a ring-shaped high-purity silicon wafer with a polished surface and a central hole arranged concentrically with the outer edge of the circle.

[0007] 2) The surface of the high-purity silicon wafer is ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water, and then dried with nitrogen gas for later use.

[0008] 3) Select a high-temperature, high-pressure single-crystal diamond as the seed crystal, whose size matches the center hole of the silicon wafer in step 1. The thickness of the single-crystal diamond should be the same as the thickness of the silicon wafer.

[0009] 4) Select good single crystal diamonds, first soak them in aqua regia for 24 hours to remove impurities, then clean the surface of the single crystal diamonds with deionized water to remove the aqua regia, and then perform ultrasonic cleaning with acetone, anhydrous ethanol and deionized water in sequence. After cleaning, blow them dry with nitrogen gas for later use.

[0010] 5) Perform plasma etching treatment on the surface of the dried single-crystal diamond seed crystal;

[0011] 6). Growth preparation

[0012] The ring-shaped high-purity silicon wafer after step 2 is placed in the middle of the molybdenum holder of the MPCVD equipment. Then, the single-crystal diamond seed crystal after step 5 is placed in the center of the ring. The growth temperature of the equipment is 850℃, the atmosphere is a mixture of methane and hydrogen, the total gas flow rate is 200 sccm, and the growth time is 12 hours.

[0013] 7) Form Si-V color centers on a single-crystal diamond seed crystal and generate polycrystalline diamond containing Si-V color centers on a silicon wafer.

[0014] Furthermore, the silicon wafer in step 1 is monocrystalline silicon, and a silicon wafer with a diameter of 50 mm and a thickness of 1.5 mm is selected as the silicon wafer.

[0015] 1.1) First, polish the silicon wafer with a polishing machine for 2 hours; until scratches appear on its surface.

[0016] 1.2) Use a laser cutter to cut a 10mm circle from the center of the silicon wafer to form a circular hole concentric with the outer edge of the circle.

[0017] Furthermore, in step 2, the silicon wafer is ultrasonically cleaned for 15 minutes each in acetone, anhydrous ethanol, and deionized water.

[0018] Furthermore, the single-crystal diamond in step 3 has a size of 4mm x 4mm and a thickness of 1.5mm.

[0019] Furthermore, in step 4, the single-crystal diamond is ultrasonically cleaned for 15 minutes each in acetone, anhydrous ethanol, and deionized water.

[0020] Furthermore, the plasma etching process in step 5 is carried out in an MPCVD equipment with an atmosphere of hydrogen and oxygen in a ratio of 99:1, a total gas flow rate of 200 sccm, and an etching temperature of 700°C.

[0021] Furthermore, in step 6, the methane concentration in the methane and hydrogen mixture is 'a', where 1% ≤ a ≤ 10%, and the remainder is hydrogen.

[0022] The beneficial effects of this invention are:

[0023] A method for preparing Si-V color centers in diamond involves placing a treated single-crystal diamond seed crystal at the center of a concentric silicon wafer. During growth, H plasma etches the Si-containing solid and releases Si atoms into the plasma atmosphere, thereby incorporating Si atoms into the diamond film to obtain Si-V color centers. Additionally, polycrystalline diamond containing Si-V color centers is formed on the concentric silicon wafer. This method firstly achieves the simultaneous growth of single-crystal and polycrystalline diamonds containing Si-V color centers. Secondly, by changing the methane concentration in the growth atmosphere, the concentration of Si-V color centers in the single-crystal diamond can be effectively controlled. This is because increasing the methane concentration leads to a higher growth rate, which enhances silicon diffusion into the diamond lattice and increases the defect concentration, resulting in more Si-hole bonding. Attached Figure Description

[0024] Figure 1 Concentric silicon wafers with a hollow center after being cut by a laser cutting machine;

[0025] Figure 2 Schematic diagram of solid-state doped growth;

[0026] Figure 3 Optical photograph of the grown single-crystal diamond;

[0027] Figure 4 Optical photograph of a concentric silicon wafer with polycrystalline diamond after growth;

[0028] Figure 5 PL spectrum of polycrystalline diamond on concentric silicon wafers;

[0029] Figure 6 PL spectrum of diamond at 3% methane concentration.

[0030] Figure 7 PL spectrum of diamond at 6% methane concentration;

[0031] Figure 8 A graph showing the relationship between fluorescence intensity and methane concentration in single-crystal diamond.

[0032] Figure 9 A graph showing the relationship between fluorescence intensity and methane concentration in polycrystalline diamond. Implementation

[0033] The following description, in conjunction with the accompanying drawings, details the implementation methods and usage of this invention.

[0034] Example 1: A method for preparing Si-V color centers in diamond, comprising the following steps;

[0035] 1) Select a ring-shaped high-purity silicon wafer with a polished surface and a central hole arranged concentrically with the outer edge of the circle.

[0036] The silicon wafer used in step 1 is monocrystalline silicon, and a silicon wafer with a diameter of 50 mm and a thickness of 1.5 mm is selected as the silicon wafer.

[0037] 1.1) First, polish the silicon wafer with a polishing machine for 2 hours to create scratches on its surface. Under the excitation of plasma, Si atoms will be more easily released at these scratches, which is more conducive to the doping of Si atoms and the preparation of Si-V color centers.

[0038] 1.2) Use a laser cutter to cut a 10mm circle from the center of the silicon wafer, forming a circular hole concentric with the outer edge of the circle, such as... Figure 1 .

[0039] 2) The surface of the high-purity silicon wafer is ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water for 15 minutes each time. After cleaning, it is dried with nitrogen gas for later use. Repeated ultrasonic cleaning is to remove impurities from the sample surface. The purpose of removing impurities is twofold: to avoid the introduction of impurities and to ensure the cleanliness of the cavity.

[0040] 3) Select a high-temperature, high-pressure monocrystalline diamond as the seed crystal, matching the size of the silicon wafer center hole from step 1. The thickness of the monocrystalline diamond should be the same as the thickness of the silicon wafer. The monocrystalline diamond in step 3 should be 4mm x 4mm and 1.5mm thick. The thicknesses of the two materials should be similar to prevent excessive temperature differences during growth, which could affect the growth process. Figure 3 .

[0041] 4) Select a good single-crystal diamond. First, soak it in aqua regia for 24 hours to remove impurities. Then, rinse the surface of the single-crystal diamond with deionized water to remove the aqua regia. Next, ultrasonically clean it in acetone, anhydrous ethanol, and deionized water for 15 minutes each. After cleaning, dry it with nitrogen gas for later use. Ultrasonic cleaning is used to remove impurities from the sample surface. The purpose of removing impurities is to avoid the introduction of impurities.

[0042] 5) The surface of the dried single-crystal diamond seed crystal is subjected to plasma etching treatment to remove surface defects and impurities. The plasma etching treatment in step 5 is carried out in an MPCVD equipment with an atmosphere of hydrogen and oxygen ratio of 99:1, a total gas flow rate of 200 sccm, and an etching temperature of 700℃. The main purpose of oxygen plasma etching is to remove residual impurities and surface defects on the surface of the single-crystal diamond to ensure the growth quality of the single-crystal diamond.

[0043] 6). Growth preparation

[0044] The ring-shaped high-purity silicon wafer from step 2 is placed in the center of the molybdenum holder in the MPCVD equipment. Then, the single-crystal diamond seed crystal from step 5 is placed in the center of the ring. Figure 2 The equipment growth temperature is 850℃, the atmosphere is a mixture of methane and hydrogen, and the total gas flow rate is 200 sccm; the growth time is 12 hours. In step 6, the methane concentration in the methane and hydrogen mixture is α = 1%, with the remainder being hydrogen.

[0045] 7) Forming Si-V color centers on a single-crystal diamond seed crystal, and generating polycrystalline diamond containing Si-V color centers on a silicon wafer, such as... Figure 4 An optical photograph of a concentric silicon wafer with polycrystalline diamond after growth, such as... Figure 5 The PL spectrum is that of polycrystalline diamond on a concentric silicon wafer.

[0046] Example 2: Example 2 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 2, the methane concentration in the methane and hydrogen mixture is a=2%, and the remainder is hydrogen.

[0047] Example 3: Example 3 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 3, the methane concentration in the methane and hydrogen mixture is a=3%, and the remainder is hydrogen. Figure 6 The PL spectrum of single-crystal diamond at a 3% methane concentration.

[0048] Example 4: Example 4 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 4, the methane concentration in the mixed gas of methane and hydrogen is a=4%, and the rest is hydrogen.

[0049] Example 5: Example 5 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 5, the methane concentration in the mixed gas of methane and hydrogen is a=5%, and the remainder is hydrogen.

[0050] Example 6: Example 6 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 6, the methane concentration in the methane and hydrogen mixture is a=6%, and the remainder is hydrogen. Figure 7 The PL spectrum of single-crystal diamond at a 6% methane concentration.

[0051] Example 7: Example 7 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 7, the methane concentration in the mixed gas of methane and hydrogen is a=7%, and the rest is hydrogen.

[0052] Example 8: Example 8 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in the methane and hydrogen mixture in step 6 of Example 8, the methane concentration ratio is a=8%, and the remainder is hydrogen.

[0053] Example 9: Example 9 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 9, the methane concentration in the mixed gas of methane and hydrogen is a=9%, and the remainder is hydrogen.

[0054] Example 10: Example 10 is basically the same as Example 1, and the similarities will not be repeated. The difference is that in step 6 of Example 10, the methane concentration in the mixed gas of methane and hydrogen is a=10%, and the remainder is hydrogen.

[0055] In the above embodiments one to ten, after growth is completed, a silicon-doped single-crystal diamond layer is homoepitaxially grown on the central single-crystal diamond, and a silicon-doped polycrystalline diamond layer is heteroepitaxially grown on the silicon concentric circles.

[0056] The inventors conducted Raman PL tests on single-crystal diamonds containing Si-V color centers and polycrystalline diamonds containing Si-V color centers obtained at different methane concentrations in the ten embodiments.

[0057] Figure 8 The results show that the fluorescence intensity of the Si-V color centers at 738 nm in single-crystal diamond increases with the increase of methane concentration during the growth process. In other words, the concentration of methane in the atmosphere during the growth process is positively correlated with the concentration of Si-V color centers in the single-crystal diamond after growth.

[0058] Similarly, Figure 9 The results show that the fluorescence intensity of the Si-V color centers at 738 nm in polycrystalline diamond increases with the increase of methane concentration during the growth process. In other words, the concentration of methane in the atmosphere during the growth process is positively correlated with the concentration of Si-V color centers in the polycrystalline diamond after growth.

[0059] The above Figure 8 and Figure 9 Statistical analysis shows that by controlling the concentration of methane in the mixed gas in step 6, the concentration of Si-V color centers in single-crystal diamond can be effectively regulated. This is because the increase in methane concentration leads to a higher growth rate, which can enhance the diffusion of silicon into the diamond lattice.

Claims

1. A method for the simultaneous preparation of Si-V color center single-crystal diamond and Si-V color center polycrystalline diamond, comprising the following steps; 1) Select a ring-shaped high-purity silicon wafer with a polished surface and a central hole arranged concentrically with the outer edge of the circle. 2) The surface of the high-purity silicon wafer is ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water, and then dried with nitrogen gas for later use. 3) Select a high-temperature, high-pressure monocrystalline diamond as the seed crystal, matching the size of the central hole in the silicon wafer from step 1). The thickness of the monocrystalline diamond should be the same as the thickness of the silicon wafer. 4) Select good single crystal diamonds, first soak them in aqua regia for 24 hours to remove impurities, then clean the surface of the single crystal diamonds with deionized water to remove the aqua regia, and then perform ultrasonic cleaning with acetone, anhydrous ethanol and deionized water in sequence. After cleaning, blow them dry with nitrogen gas for later use. 5) Perform plasma etching treatment on the surface of the dried single-crystal diamond seed crystal; 6). Growth preparation The ring-shaped high-purity silicon wafer after step 2) is placed in the middle of the molybdenum support of the MPCVD equipment. Then, the single crystal diamond seed crystal after step 5 is placed in the center of the ring. The growth temperature of the equipment is 850℃, the atmosphere is a mixture of methane and hydrogen, the total gas flow rate is 200 sccm, and the growth time is 12 hours. 7) Forming single-crystal diamond containing Si-V color centers on a single-crystal diamond seed crystal, and generating polycrystalline diamond containing Si-V color centers on a silicon wafer.

2. The method for simultaneous preparation of Si-V color-center single-crystal diamond and Si-V color-center polycrystalline diamond according to claim 1, characterized in that: The silicon wafer used in step 1) is monocrystalline silicon, and a silicon wafer with a diameter of 50 mm and a thickness of 1.5 mm is selected as the silicon wafer. 1.1) First, polish the silicon wafer with a polishing machine for 2 hours; until scratches appear on its surface. 1.2) Use a laser cutter to cut a 10mm circle from the center of the silicon wafer to form a circular hole concentric with the outer edge of the circle.

3. The method for simultaneous preparation of Si-V color-center single-crystal diamond and Si-V color-center polycrystalline diamond according to claim 1, characterized in that: In step 2), the silicon wafer is ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water for 15 minutes each.

4. The method for simultaneous preparation of Si-V color-center single-crystal diamond and Si-V color-center polycrystalline diamond according to claim 1, characterized in that: The single-crystal diamond in step 3) has a size of 4mm x 4mm and a thickness of 1.5mm.

5. The method for simultaneous preparation of Si-V color center single-crystal diamond and Si-V color center polycrystalline diamond according to claim 1, characterized in that: In step 4), the single-crystal diamond is ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water for 15 minutes each.

6. The method for simultaneous preparation of Si-V color-center single-crystal diamond and Si-V color-center polycrystalline diamond according to claim 1, characterized in that: The plasma etching process in step 5) is carried out in an MPCVD equipment with a hydrogen to oxygen ratio of 99:1, a total gas flow rate of 200 sccm, and an etching temperature of 700℃.

7. The method for simultaneous preparation of Si-V color center single-crystal diamond and Si-V color center polycrystalline diamond according to claim 1, characterized in that: In step 6), the methane concentration in the methane and hydrogen mixture is 'a', where 1% ≤ a ≤ 10%, and the remainder is hydrogen.

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