Method for manufacturing regular array of single NV color centers in diamond and structure

Abstract

The disclosure provides a method for manufacturing a diamond single NV color center regular array structure, comprising: pretreating a diamond surface to obtain a pretreated diamond surface. Uniformly coating poly methyl methacrylate mixed glue on the pretreated diamond surface to form a poly methyl methacrylate film, baking and reinforcing, then plating a conductive film on the poly methyl methacrylate film, and then performing electron beam exposure treatment, developing the exposed sample to obtain a diamond sample with a regular array. The diamond sample with a regular array is subjected to 14 N ion implantation, cleaning to remove poly methyl methacrylate mixed glue on the surface of the sample, then annealing, and cleaning to obtain a diamond single NV color center regular array structure.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of quantum materials, and in particular to a method for manufacturing a regular array of single NV color centers of diamond and a structure. BACKGROUND

[0002] The nitrogen-vacancy color center structure refers to a luminescent point defect structure formed by a nitrogen atom replacing a carbon atom in a diamond lattice and a vacancy in the vicinity under the influence of specific physical conditions. The nitrogen-vacancy color center is divided into two types and can be converted by optical control. The nitrogen-vacancy color center (NV center for short) with a negative electron has strong fluorescence effect, short coherence time of electron spin, and can be operated and detected by laser and microwave, and is concerned in the field of quantum control and quantum computing. - The color center, hereinafter referred to as NV color center, has strong fluorescence effect, short coherence time of electron spin, and can be operated and detected by laser and microwave, and is concerned in the field of quantum control and quantum computing.

[0003] In the related art, the diamond NV color center structure prepared is disordered inside, and the same NV color center structure cannot be quickly located before and after testing, which seriously affects the stability and accuracy of high-precision regulation and testing of the spin state. Meanwhile, how to improve the coherence time and generation efficiency of the diamond NV color center structure is also the research focus of the diamond NV color center structure. SUMMARY

[0004] Therefore, in order to improve the coherence time and generation efficiency of the diamond NV color center structure and overcome the technical problem of disorder inside the diamond NV color center structure under normal circumstances, a diamond NV color center structure convenient for accurate positioning is constructed, and a method for manufacturing a regular array of single NV color centers of diamond and a structure are provided.

[0005] In one aspect of the present disclosure, a method for manufacturing a regular array of single NV color centers of diamond is provided, comprising:

[0006] The surface of the diamond is pretreated to obtain a pretreated diamond surface;

[0007] The pretreated diamond surface is subjected to uniform glue treatment, and polymethyl methacrylate mixed glue is uniformly applied to form a polymethyl methacrylate film. After the polymethyl methacrylate film is baked and reinforced, a conductive film is formed on the polymethyl methacrylate film, and then electron beam exposure treatment is performed. The exposed sample is developed to obtain a diamond sample with a regular array;

[0008] The diamond sample with a regular array is subjected to 14 N ion implantation, and the polymethyl methacrylate mixed glue on the surface of the sample is removed by cleaning. Then, annealing and cleaning treatment are performed to obtain a regular array of single NV color centers of diamond.

[0009] According to the embodiment of the present disclosure, the pre-treatment and cleaning treatment includes acid pickling treatment and ultrasonic cleaning treatment, wherein the acid pickling treatment is to mix nitric acid, perchloric acid and concentrated sulfuric acid in a proportion of 1:1:1, and to stir and heat in silicon oil at 190-210°C for 1.9-2h;

[0010] The ultrasonic cleaning treatment is to sequentially use acetone, isopropyl alcohol and deionized water to ultrasonically clean the diamond for 160-200s. According to the embodiment of the present disclosure, the uniform glue treatment includes pasting the pre-treated diamond surface on the edge of a silicon wafer, and uniformly dropping a polymethyl methacrylate mixed glue on the pre-treated diamond surface to form a polymethyl methacrylate film.

[0011] According to the embodiment of the present disclosure, the polymethyl methacrylate mixed glue is obtained by mixing polymethyl methacrylate-A4 and polymethyl methacrylate-A7 in a proportion of 2:1-3:1;

[0012] The thickness of the polymethyl methacrylate film is 280-320nm;

[0013] The uniform glue time is 38-42s, and the uniform glue machine rotation speed is 3500-4500r / s;

[0014] The baking treatment is to hot plate bake the polymethyl methacrylate film at 180-200°C for 200-220s.

[0015] According to the embodiment of the present disclosure, the film plating treatment is thermal evaporation film plating, the film plating thickness is in the range of 10±0.1nm, and the film plating speed is 0.1-0.2nm / s.

[0016] According to the embodiment of the present disclosure, the exposure pattern of the electron beam exposure treatment is a cross strip pattern with a plurality of strip widths of 10-11μm and a small hole pattern with a pitch in the range of 95-105nm in a middle array distribution; wherein the exposure energy is 20keV, the exposure dose of the cross strip region is 210-240μC / cm 2 , and the exposure dose of the small hole region is 0.7-0.8μC / cm 2 .

[0017] According to the embodiment of the present disclosure, the developing operation includes soaking the diamond sample in an organic alkali developing solution for 1±0.1min, then placing it in deionized water for 8-12s, blowing dry, then soaking it in the developing solution for 35-45s, then placing it in a fixing solution, soaking for 30-40s, and air drying.

[0018] According to the embodiment of the present disclosure, the ion implantation operation includes selecting 14 N ions for implantation, and the implantation dose is (2±0.1)×10 11 / cm 2 The implantation energy is 40-42 keV, and the implantation current is 50-70 nA.

[0019] According to the embodiment of the present disclosure, the annealing operation includes that the diamond sample is heated to a first temperature under a pressure of (4-5) x 10 -5 Pa, maintained for a first time length, then linearly increased to a second temperature, maintained for a second time length, and then gradually returned to room temperature and standard atmospheric pressure environment, wherein,

[0020] The first temperature includes 395-405 DEG C, the first time length includes 0.9-1.1 h, the second temperature includes 800-820 DEG C, and the second time length includes 1.9-2.1 h.

[0021] In another aspect of the present disclosure, a diamond single NV color center regular array structure is provided, wherein the single NV color center regular array structure refers to a diamond structure with regular arrangement in which only one NV color center structure exists within the range of 350 nm of the confocal optical diffraction limit.

[0022] The diamond single NV color center regular array structure and the manufacturing method thereof provided by the present disclosure have the following beneficial effects:

[0023] (1) According to the embodiment of the present disclosure, the thickness of the electron beam entering the surface of the diamond can be effectively controlled by using the mask regulation method, and the injection position and depth of the nitrogen ions are controlled, so that the coherence time of the NV color center structure is increased from the conventional millisecond and nanosecond level to the microsecond level, and the application of the diamond NV color center structure in the field of quantum computing and quantum control is widened. At the same time, the fluorescence efficiency of the diamond NV color center structure is also improved, which can not only prepare shallow color centers within 5 nm of the surface of the diamond, but also make the fluorescence count at a depth of 30 nm from the surface of the diamond significantly greater than that of the surface NV color center, thereby improving the coupling strength of the NV color center and the out-of-body spin of the diamond, which is beneficial to the quantum sensing out-of-body detection of the diamond NV color center structure.

[0024] (2) According to the embodiment of the present disclosure, the thickness of the mask layer is precisely regulated by combining the conductive film and the polymethyl methacrylate mixed glue in the form of a mask. By precisely controlling the nitrogen ion injection amount, the success rate of the single NV color center structure in the diamond reaches 80%, and the regular array structure of the diamond NV color center is constructed, so that only one NV color center structure exists within the range of 350 nm of the confocal optical diffraction limit.

[0025] (3) The preparation method of the regular array of single NV color centers in diamond disclosed in the present disclosure adopts a mask structure of PMMA mixed film and surface conductive layer to replace the commonly used single type electron beam photoresist and surface conductive glue, so as to replace the commonly used single type electron beam photoresist and surface conductive glue with more precise control of ion implantation, ensure the uniformity of the thickness of the mask layer, reduce the possibility of penetrating the mask layer during ion implantation, and ensure that the ion depth of the array region meets the set requirements, so that the quality of the single NV color center structure of diamond has great consistency. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a flowchart of the preparation of the regular array of single NV color centers in diamond disclosed in the present disclosure;

[0027] Figure 2 is a continuous wave optical magnetic resonance spectrum line graph of the regular array of single NV color centers in diamond disclosed in the present disclosure;

[0028] Figure 3 is a confocal scanning (within 350 nm) imaging result graph of the regular array of single NV color centers in diamond disclosed in the present disclosure;

[0029] Figure 4 is a test result graph of the coherence time of the regular array of single NV color centers in diamond disclosed in the present disclosure. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present disclosure clearer and more apparent, the following will combine specific embodiments and refer to the drawings to make a further detailed description of the present disclosure.

[0031] In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. However, it will be apparent to those skilled in the art that one or more embodiments can be practiced without these specific details. In other instances, well-known structures and features have been omitted in order to avoid obscuring the present disclosure.

[0032] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The terms "include", "contain" and the like used herein indicate the existence of the described features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0033] All terms used herein, including technical and scientific terms, have the meanings as commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein are to be interpreted as having a meaning that is consistent with the context of the specification, and should not be interpreted in an idealized or overly formal sense.

[0034] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges are provided as example of the boundaries of the ranges and are not intended to be limiting unless otherwise specified. Each range between any stated value or implied value and the bottom of the range, between any stated value or implied value and the top of the range, and between each stated or implied value can be included in the range, unless specifically excluded. The same applies to any stated or implied value and any other stated or implied value, even if not explicitly specified in the same sentence.

[0035] It should be noted that the technical terms or scientific terms used in the present disclosure should be understood as the general meaning understood by those skilled in the art unless otherwise defined. If the description of "first", "second" and the like is involved throughout the text, the "first", "second" and the like are only used to distinguish similar objects, and cannot be understood as indicating or implying the relative importance, the order of precedence or implicitly indicating the number of technical features indicated. It should be understood that the data described by "first", "second" and the like can be interchanged under appropriate circumstances.

[0036] It should be noted that the described embodiments are only part of the embodiments of the present disclosure, not all the embodiments. Based on the embodiments in the present disclosure, other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present disclosure.

[0037] The energy level structure of NV color center structure in diamond can be divided into excited state and ground state, both of which are spin triplet state. When there is no external magnetic field, the two energy levels of m s = ± 1 are degenerate, and there is a 2.87 GHz zero field splitting between the energy level of m s = 0, and there is a certain difference in light emission intensity. At room temperature, the zero phonon line of diamond NV color center structure is located near 637 nm, and its light emission band is usually between 650-800 nm. The strongest absorption spectrum is in the green light band, so 532 nm green light is usually used to initialize and read NV color center structure. Through the microwave pulse of the radiation resonance frequency band, the state of the spin can be controlled with high precision, that is, the initialization, arbitrary control and reading of spin bits required for quantum computing and quantum simulation can be realized.

[0038] The disclosure adjusts the thickness of the mask layer, the uniform glue time, the thickness of the conductive aluminum film, the development time, and the energy and dose of electron beam lithography and other conditions by adopting the mask method, controls the position and depth of nitrogen ion implantation, effectively optimizes the success rate, coherence time and fluorescence of the diamond NV color center structure, and constructs a single diamond NV color center structure by precisely controlling the injection amount, and constructs a single diamond NV color center structure with a regular array by selecting a mask pattern, which is conducive to quickly locating the same NV color center structure, and ensures the high-precision regulation and testing stability and accuracy of the spin state in the experimental observation process.

[0039] Figure 1 is a manufacturing process schematic diagram of a single diamond NV color center regular array in the disclosure.

[0040] In one aspect of the disclosure, a manufacturing method of a single diamond NV color center regular array structure is disclosed, as shown in Figure 1 S1-S3.

[0041] S1: pretreating the surface of the diamond to obtain a pretreated diamond surface;

[0042] S2: performing uniform glue treatment on the pretreated diamond surface, uniformly applying polymethyl methacrylate (PMMA) mixed glue to form a polymethyl methacrylate film, baking and reinforcing the polymethyl methacrylate film, then plating a conductive film on the polymethyl methacrylate film, and then performing electron beam exposure treatment, developing the exposed sample to obtain a diamond sample with a regular array;

[0043] S3: performing 14 N ion implantation on the diamond sample with a regular array, removing the PMMA mixed glue on the surface of the sample, then annealing, and then cleaning to obtain a single diamond NV color center regular array structure.

[0044] According to the embodiment of the disclosure, after the pretreatment in step S1, the diamond sample needs to be detected by fluorescence. The surface fluorescence count of the diamond sample should be less than 2000s -1 If the surface fluorescence count is greater than 2000s -1 , then step S1 needs to be repeated to eliminate the influence of surface background fluorescence on the signal-to-noise ratio of confocal imaging.

[0045] According to the method of mask regulation, the polymethyl methacrylate mixed glue can effectively control the thickness of the electron beam entering the diamond surface, the injection position and depth of the nitrogen ion are controlled, so that the coherence time of the NV color center structure is improved from the conventional millisecond and nanosecond level to the microsecond level, and the application of the diamond NV color center structure in the field of quantum computing and quantum control is widened. At the same time, the fluorescence efficiency of the diamond NV color center structure is also improved, not only can the shallow color center within 5nm of the diamond surface be prepared, but also the fluorescence count at a depth of 30nm from the diamond surface is significantly greater than that of the surface NV color center, thereby improving the coupling strength of the NV color center and the out-of-body spin of the diamond, which is beneficial to the out-of-body detection of the quantum sensing of the diamond NV color center structure.

[0046] According to the method of mask regulation, the polymethyl methacrylate mixed glue can effectively control the thickness of the electron beam entering the diamond surface, the injection position and depth of the nitrogen ion are controlled, so that the coherence time of the NV color center structure is improved from the conventional millisecond and nanosecond level to the microsecond level, and the application of the diamond NV color center structure in the field of quantum computing and quantum control is widened. At the same time, the fluorescence efficiency of the diamond NV color center structure is also improved, not only can the shallow color center within 5nm of the diamond surface be prepared, but also the fluorescence count at a depth of 30nm from the diamond surface is significantly greater than that of the surface NV color center, thereby improving the coupling strength of the NV color center and the out-of-body spin of the diamond, which is beneficial to the out-of-body detection of the quantum sensing of the diamond NV color center structure.

[0047] According to the method of mask regulation, the polymethyl methacrylate mixed glue can effectively control the thickness of the electron beam entering the diamond surface, the injection position and depth of the nitrogen ion are controlled, so that the coherence time of the NV color center structure is improved from the conventional millisecond and nanosecond level to the microsecond level, and the application of the diamond NV color center structure in the field of quantum computing and quantum control is widened. At the same time, the fluorescence efficiency of the diamond NV color center structure is also improved, not only can the shallow color center within 5nm of the diamond surface be prepared, but also the fluorescence count at a depth of 30nm from the diamond surface is significantly greater than that of the surface NV color center, thereby improving the coupling strength of the NV color center and the out-of-body spin of the diamond, which is beneficial to the out-of-body detection of the quantum sensing of the diamond NV color center structure.

[0048] According to the method of mask regulation, the polymethyl methacrylate mixed glue can effectively control the thickness of the electron beam entering the diamond surface, the injection position and depth of the nitrogen ion are controlled, so that the coherence time of the NV color center structure is improved from the conventional millisecond and nanosecond level to the microsecond level, and the application of the diamond NV color center structure in the field of quantum computing and quantum control is widened. At the same time, the fluorescence efficiency of the diamond NV color center structure is also improved, not only can the shallow color center within 5nm of the diamond surface be prepared, but also the fluorescence count at a depth of 30nm from the diamond surface is significantly greater than that of the surface NV color center, thereby improving the coupling strength of the NV color center and the out-of-body spin of the diamond, which is beneficial to the out-of-body detection of the quantum sensing of the diamond NV color center structure.

[0049] The acid pickling process is to mix nitric acid, perchloric acid and concentrated sulfuric acid in a proportion of 1:1:1, and stir and heat in silicon oil at 190-210 DEG C for 1.9-2h;

[0050] The ultrasonic cleaning process is to sequentially clean the diamond with acetone, isopropanol and deionized water for 160-200s.

[0051] According to the method of mask regulation, the polymethyl methacrylate mixed glue can effectively control the thickness of the electron beam entering the diamond surface, the injection position and depth of the nitrogen ion are controlled, so that the coherence time of the NV color center structure is improved from the conventional millisecond and nanosecond level to the microsecond level, and the application of the diamond NV color center structure in the field of quantum computing and quantum control is widened. At the same time, the fluorescence efficiency of the diamond NV color center structure is also improved, not only can the shallow color center within 5nm of the diamond surface be prepared, but also the fluorescence count at a depth of 30nm from the diamond surface is significantly greater than that of the surface NV color center, thereby improving the coupling strength of the NV color center and the out-of-body spin of the diamond, which is beneficial to the out-of-body detection of the quantum sensing of the diamond NV color center structure.

[0052] According to the method of mask regulation, the polymethyl methacrylate mixed glue can effectively control the thickness of the electron beam entering the diamond surface, the injection position and depth of the nitrogen ion are controlled, so that the coherence time of the NV color center structure is improved from the conventional millisecond and nanosecond level to the microsecond level, and the application of the diamond NV color center structure in the field of quantum computing and quantum control is widened. At the same time, the fluorescence efficiency of the diamond NV color center structure is also improved, not only can the shallow color center within 5nm of the diamond surface be prepared, but also the fluorescence count at a depth of 30nm from the diamond surface is significantly greater than that of the surface NV color center, thereby improving the coupling strength of the NV color center and the out-of-body spin of the diamond, which is beneficial to the out-of-body detection of the quantum sensing of the diamond NV color center structure.

[0053] According to the embodiment of the present disclosure, using a magnetic stirrer to stir the solution can optimize the pickling effect.

[0054] According to the embodiment of the present disclosure, the acid pickling and ultrasonic cleaning treatment of the diamond sample can remove organic impurities on the surface of the diamond sample.

[0055] According to the embodiment of the present disclosure, in step S2, the uniform glue treatment includes pasting the pretreated diamond surface on the edge of the silicon wafer, uniformly dropping the polymethyl methacrylate mixed glue on the pretreated diamond surface, and forming a polymethyl methacrylate film.

[0056] According to the embodiment of the present disclosure, before step S2, it is necessary to observe the surface of the diamond sample under a microscope to ensure that the surface is clean and free of impurities. If there are impurities, the above ultrasonic cleaning treatment needs to be repeated.

[0057] According to the embodiment of the present disclosure, in step S2, pasting the pretreated diamond surface on the edge of the silicon wafer can ensure the uniformity of the uniform glue treatment.

[0058] According to the embodiment of the present disclosure, in step S2, the polymethyl methacrylate mixed glue is a mixture of polymethyl methacrylate-A4 (PMMA-A4) and polymethyl methacrylate-A7 (PMMA-A7) in a ratio of 2:1 to 3:1.

[0059] The thickness of the polymethyl methacrylate film is 280nm to 320nm.

[0060] The uniform glue time is 38s to 42s, and the uniform glue machine speed is 3500r / s to 4500r / s.

[0061] The baking treatment is a hot plate baking of the polymethyl methacrylate film at 180 to 200℃ for 200 to 220s.

[0062] According to the embodiment of the present disclosure, the ratio of polymethyl methacrylate-A4 and polymethyl methacrylate-A7 needs to be accurately determined according to the thickness of the polymethyl methacrylate film. In the preparation method of the present disclosure, the two are required to be mixed to accurately control the thickness of the polymethyl methacrylate film. The two can be selected as 2:1, 2.5:1, 3:1, etc. The thickness of the polymethyl methacrylate film needs to be measured using a Bruker-type step meter to measure the thickness, which can be selected as 280nm, 300nm, 320m, etc. The uniform glue time can be selected as 38s, 40s, 42s, etc. The uniform glue machine speed can be selected as 3500r / s, 4000r / s, 4500r / s, etc. The baking treatment temperature can be selected as 180℃, 190℃, 200℃, etc. The baking treatment time can be selected as 200s, 210s, 220s, etc.

[0063] According to the embodiment of the present disclosure, in step S2, the film coating treatment is thermal evaporation film coating, the film coating thickness is in the range of 10±0.1 nm, and the film coating speed is 0.1-0.2 nm / s.

[0064] According to the embodiment of the present disclosure, preferably, the film coating material is selected as aluminum, and the instrument model that can be selected is TH500H.

[0065] According to the embodiment of the present disclosure, the film coating thickness needs to be strictly guaranteed to be uniform, which can be 9.9 nm, 10.0 nm, 10.1 nm, etc., and the film coating speed needs to be strictly guaranteed to be uniform, which can be 0.1 nm / s, 0.15 nm / s, 0.2 nm / s, etc.

[0066] According to the embodiment of the present disclosure, the thermal evaporation film coating technology can guarantee the uniformity of the evaporation source temperature in the film coating process, the evaporation process temperature is less than that of other film coating technologies, which is convenient for temperature control and simple operation. At the same time, the flatness of the PMMA film can be effectively protected.

[0067] According to the embodiment of the present disclosure, in step S2, the exposure pattern of the electron beam exposure treatment is a cross strip pattern with a strip width of 10-11 μm and a small hole pattern with a pitch in the range of 95-105 nm in a middle array distribution, and the consistency of the pattern needs to be strictly guaranteed; wherein the exposure energy is 20 keV, the exposure dose of the cross strip region is 210-240 μC / cm 2 , and the exposure dose of the small hole region is 0.7-0.8 μC / cm 2 .

[0068] According to the embodiment of the present disclosure, the instrument for electron beam exposure can be selected as Raithpioneer two, the strip width of the cross strip pattern in the exposure pattern can be selected as 10 μm, 10.5 μm, 11 μm, etc., the exposure dose can be selected as 210 μC / cm 2 , 220 μC / cm 2 , 240 μC / cm 2 , etc., the pitch of the small hole pattern can be selected as 95 nm, 100 nm, 105 nm, etc., and the exposure dose can be selected as 0.7 μC / cm 2 , 0.75 μC / cm 2 , 0.8 μC / cm 2 , etc.

[0069] According to the embodiment of the present disclosure, the cross strip pattern and the small hole pattern as the middle array uniform distribution are selected to construct the regular array of the diamond sample surface, which is beneficial to the positioning of the electron beam exposure and the subsequent ion implantation site.

[0070] According to the embodiment of the present disclosure, in step S2, the developing operation includes soaking the diamond sample in the organic alkali developing solution for 1±0.1 min, then placing it in deionized water for 8-12 s, and then blowing dry, and then soaking it in the developing solution for 35-45 s, and then placing it in the fixing solution, soaking for 30-40 s with shaking, and then air drying.

[0071] According to the embodiment of the present disclosure, the organic alkali developing solution (AZ300) can be selected as 2.38% concentration of tetramethylammonium hydroxide (TMAH), and the soaking time can be selected as 55 s, 55 s, 55 s, etc.

[0072] According to the embodiment of the present disclosure, the developing solution can be selected as an EBL developing solution (electron beam lithography, EBL, also known as an electron beam exposure system), wherein the composition of the developing solution is preferably methyl isobutyl ketone (MIBK): indolepropionic acid (IPA) = 1:3, and the soaking time in the developing solution can be selected as 35 s, 40 s, 45 s, etc.

[0073] According to the embodiment of the present disclosure, the fixing solution is preferably an IPA solution, and the shaking soaking time in the fixing solution can be selected as 30 s, 35 s, 40 s, etc. Shaking soaking can make the soaking more sufficient while not damaging the mask.

[0074] According to the embodiment of the present disclosure, after step S2 is completed, the thickness of the PMMA film of the exposed diamond sample needs to be detected again. According to the exposure pattern of the present disclosure, which is a cross strip and a small hole distributed in the middle array, the preferred experimental instrument is a Bruker type step meter, and the thinnest needle of the probe is 2 um, which can better measure the film thickness of the strip pattern.

[0075] According to the embodiment of the present disclosure, in step S3, the ion implantation operation includes selecting 14 N ions for implantation, the implantation dose is (2±0.1)×10 11 cm -2 , the implantation energy is 40-42 keV, and the implantation beam current is 50-70 nA.

[0076] According to the embodiment of the present disclosure, the implantation dose can be selected as 1.9×10 11 / cm -2 , 2.0×10 11 / cm -2 , 2.1×10 11 / cm -2The implantation energy can be 40 keV, 41 keV, 42 keV, etc., and the implantation current can be 50 nA, 60 nA, 70 nA, etc.

[0077] According to the embodiments of the present disclosure, the energy of ion implantation is determined by simulating the state of the diamond substrate material and the mixed resist mask by ion implantation software SRIM to determine the required implantation energy to ensure that the mask layer is not penetrated. During ion implantation, the implantation current should be as low as possible according to the actual situation to make the implanted ions more uniform.

[0078] According to the embodiments of the present disclosure, the diamond sample after ion implantation is also cleaned in step S3, and the cleaning solvent is preferably acetone solution to remove the PMMA film on the surface of the diamond sample.

[0079] According to the embodiments of the present disclosure, the annealing operation includes heating the diamond sample to a first temperature at a pressure of (4-5) x 10 -5 Pa, maintaining the first temperature for a first time, then linearly increasing the temperature to a second temperature, maintaining the second temperature for a second time, and then gradually returning to room temperature and standard atmospheric pressure environment, wherein,

[0080] The first temperature includes 395-405℃, the first time includes 0.9-1.1h, the second temperature includes 800-820℃, and the second time includes 1.9-2.1h.

[0081] According to the embodiments of the present disclosure, the pressure environment of the annealing operation can be 4 x 10 -5 Pa, 4.5 x 10 -5 Pa, 5 x 10 - 5 Pa, etc., the first temperature can be 395℃, 400℃, 405℃, etc., the first time can be 0.9h, 1.0h, 1.1h, etc., the second temperature can be 800℃, 810℃, 820℃, etc., and the second time can be 1.9h, 2.0h, 2.1h, etc.

[0082] According to the embodiments of the present disclosure, after the annealing operation is completed, the temperature needs to be gradually reduced to room temperature, and then the low pressure is broken, and the gas pressure is restored to standard atmospheric pressure to ensure safety.

[0083] According to the embodiments of the present disclosure, the purpose of the pickling operation after the annealing operation is completed is to remove the graphite layer generated on the surface of the diamond sample after the ion implantation step and the annealing step.

[0084] In another aspect of the present disclosure, a regular array structure of single NV color centers in diamond is disclosed. The regular array structure of single NV color centers in diamond refers to a diamond structure with regular arrangement in which only one NV color center structure exists within the range of 350 nm confocal optical diffraction limit.

[0085] Figure 2 is a continuous wave optical magnetic resonance spectrum line diagram of a regular array structure of single NV color centers of diamond in the disclosure.

[0086] As shown in Figure 2 , it can be seen that the structure prepared by the disclosure has a zero-field splitting phenomenon at 2.87GHz, which proves that the structure prepared by the disclosure is a qualified diamond NV color center structure.

[0087] Figure 3 is a confocal scanning (within 350nm) imaging result diagram of a diamond NV color center in an embodiment of the disclosure.

[0088] As shown in Figure 3 , the diamond prepared by the above preparation method has only one fluorescent point in the range of confocal scanning (within 350nm), that is, a single NV color center structure of diamond. By precisely controlling the nitrogen ion implantation amount, the success rate of the single NV color center structure in the diamond reaches 80%. By the mask method, a regular array structure of diamond NV color centers is constructed, so that there is only one NV color center structure within the range of 350nm confocal optical diffraction limit.

[0089] Figure 4 is a test result diagram of the coherence time of a regular array structure of single NV color centers in the disclosure.

[0090] As shown in Figure 4 , during the repeatability determination of the coherence time, it can be seen from the normalized fitting that the coherence time of the regular array structure of single NV color centers of the diamond prepared by the disclosure can reach 2m. It is verified that the coherence time of the regular array structure of single NV color centers of the diamond prepared by the method proposed in the disclosure can be improved from the conventional millisecond, nanosecond level to the microsecond level, which widens the application of the diamond NV color center structure in the field of quantum computing and quantum control.

[0091] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the disclosure. It should be understood that the above description is only a specific embodiment of the disclosure and is not used to limit the disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the disclosure shall be included in the protection scope of the disclosure.

Claims

1. A method for fabricating a regular array structure of a single diamond NV color center, characterized in that, The manufacturing method includes the following steps: The diamond surface is pretreated to obtain the pretreated diamond surface; The pretreated diamond surface is subjected to a spin coating process, where a polymethyl methacrylate (PMMA) mixture is uniformly coated to form a PMMA film. After baking and hardening the PMMA film, a conductive film is deposited on the PMMA film. Then, electron beam exposure is performed, followed by development to obtain a diamond sample with a regular array. The spin coating process includes attaching the pretreated diamond surface to the edge of a silicon wafer, uniformly dripping the PMMA mixture onto the pretreated diamond surface to form a PMMA film. The PMMA mixture is a mixture of PMMA-A4 and PMMA-A7 in a ratio of 2:1 to 3:

1. The thickness of the PMMA film is 280 nm to 320 nm, the spin coating time is 38 s to 42 s, and the spin coater speed is 3500 to 4500 rpm. r / s, the baking treatment is to bake the polymethyl methacrylate film on a hot plate at 180-200°C for 200-220s; The diamond sample with the regular array was subjected to 14 Nitrogen ion implantation was performed, followed by cleaning to remove the polymethyl methacrylate (PMMA) mixture from the sample surface. Annealing and subsequent cleaning resulted in a regular array structure of individual diamond NV color centers. The annealing process included tempering the diamond sample at (4–5) × 10⁻⁶ Å. -5 Under a pressure of Pa, the temperature is raised to a first temperature and held for a first duration. Then, the temperature is linearly raised to a second temperature and held stably for a second duration. Finally, the room temperature and standard atmospheric pressure environment are gradually restored. The first temperature ranges from 395 to 405 °C, and the first duration ranges from 0.9 to 1.1 h. The second temperature ranges from 800 to 820 °C, and the second duration ranges from 1.9 to 2.1 h.

2. The manufacturing method according to claim 1, characterized in that, The pretreatment and the cleaning treatment include acid washing and ultrasonic cleaning, wherein... The pickling process involves mixing nitric acid, perchloric acid, and concentrated sulfuric acid in a 1:1:1 ratio and stirring and heating the mixture in silicone oil at 190°C–210°C for 1.9–2 hours. The ultrasonic cleaning process involves sequentially ultrasonically cleaning the diamond with acetone, isopropanol, and deionized water for 160–200 seconds.

3. The manufacturing method according to claim 1, characterized in that, The coating process is a thermal evaporation coating, with a coating thickness ranging from 10±0.1 nm and a coating speed of 0.1 to 0.2 nm / s.

4. The manufacturing method according to claim 1, characterized in that, The electron beam exposure process comprises multiple cross-shaped stripe patterns with a width of 10–11 μm and a small hole pattern arranged in a central array with a spacing of 95 nm–105 nm; wherein... The exposure energy is 20 keV, and the exposure dose in the cross-shaped strip area is 210–240 μC / cm. 2 The exposure dose in the aperture region is 0.7–0.8 μC / cm. 2 .

5. The manufacturing method according to claim 1, characterized in that, The developing process includes immersing the diamond sample in an organic alkaline developing solution for 1 ± 0.1 min, then immersing it in deionized water for 8–12 s and drying it, then immersing it in the developing solution for 35–45 s, then immersing it in the fixing solution, shaking and soaking it for 30–40 s, and finally air-drying it.

6. The manufacturing method according to claim 1, characterized in that, The ion implantation operation includes selecting 14 N ions were implanted at a dose of (2±0.1)×10⁻⁶. 11 / cm 2 The injection energy was 40–42 keV, and the injection beam current was 50–70 nA.

7. A regular array structure of single NV color centers of diamond prepared by the manufacturing method according to any one of claims 1 to 6, characterized in that, The single NV color center regular array structure refers to a diamond structure with a regular arrangement in which only one NV color center exists within the confocal optical diffraction limit of 350 nm.

Images