JP2014169195A - Diamond single crystal having diamond nv optical center - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a diamond single crystal having NV optical centers arranged in a desired size and/or shape on a desired surface and/or in a space in a crystal, and NV optical centers automatically arranged in a desired size and/or shape on a desired surface and/or in space in a crystal during growing a diamond without a post-process, using a CVD method capable of growing a high quality diamond single crystal.SOLUTION: A diamond single crystal 2 having nitrogen-vacancy compound defects 1 automatically arranged on a surface of the crystal and/or in a space of the crystal during crystal growth of a diamond by homoepitaxial growth is manufactured by controlling and growing the diamond in a step flow mode at a crystal growth rate of 50 nm/h or less using a microwave plasma CVD method after forming variation of a local off-angle on a diamond single crystal substrate using the substrate having an off-angle of 0° or more and 0.5° or less as a substrate.

Description

  The present invention relates to a diamond single crystal having an NV optical center, and more particularly to a diamond single crystal arranged in a desired size and / or shape within a desired crystal surface and / or space.

  Recently, attention has been focused on a nitrogen-vacancy composite defect (hereinafter referred to as “NV optical center”) that retains one electric charge in a diamond crystal. FIG. 1 is a diagram showing a lattice model of the NV optical center. This defect can emit a single photon and further becomes a qubit by spin manipulation of the retained electrons. A special reason for diamond compared to other materials typified by silicon is that it can all operate at room temperature. In particular, electron spin manipulation has been observed to have a particularly long millisecond lifetime as a solid at room temperature. For this reason, it has been said that it can only operate at extremely low temperatures, but the potential of a solid-state quantum device or a micromagnetic sensor capable of operating at room temperature that combines the features of a single photon source and a qubit is Expectation and attention for the optical center are gathered (Non-Patent Document 1).

Since the potential as a solid quantum device or a micro magnetic sensor by the NV optical center of diamond has been confirmed, how to artificially form, arrange, and detect the NV optical center, which is the resource of the device, in the diamond, The demand for engineering elements has become an issue.
For example, matching with a nanoscale resonator (nanowire, microsphere, photonic crystal, etc.) is essential to efficiently excite the NV optical center and collect a single photon. . For matching with these resonators, it is required to arrange the NV optical center at a density that requires at least the very surface (depth of 100 nm or less) of diamond. In addition, in order to realize multi-qubits for quantum computation, a technique for regularly arranging NV optical centers in a diamond crystal (an interval of about several tens of nanometers) is required. Furthermore, in order to use as a micro magnetic sensor, the signal decreases in proportion to 1 / L ³ of the distance (L) from the surface, so the NV optical center is placed on the pole surface (a depth of about 5 nm or less from the surface). It is necessary to arrange with the required density.

  In order to artificially form the NV optical center, it is necessary to introduce vacancies simultaneously with nitrogen atoms in diamond as a first step (Non-patent Document 2). Currently, nitrogen atoms are introduced by using an ion implantation method after preparing diamond, or by introducing nitrogen atoms (such as nitrogen-containing gas) into the raw material at the same time during diamond synthesis. Patent Document 3) is used.

  In the former ion implantation method, it has become possible to introduce a desired amount of nitrogen atoms into diamond in a desired arrangement by improving the ion beam focusing technique and the controllability of the ion amount. However, the ion implantation method usually irradiates the substrate with ions accelerated from several tens of kV to several hundreds of kV, so that vacancies are introduced simultaneously with nitrogen, but the distribution of injected ions is expanded, Residual crystal damage caused by ion implantation cannot be avoided. In particular, the ion distribution due to channeling is sensitive to the influence of crystal direction, quality, incident ion energy, implantation amount, substrate temperature, surface shape, and the like, making it difficult to reproduce and predict the ion distribution. In order to minimize the influence of channeling, attempts have been made to tilt the substrate and minimize the annealing and ion acceleration voltage in order to minimize damage to the crystal. Since the necessary holes are not sufficiently supplied, the formation efficiency of the NV optical center is extremely low, about 1%.

  On the other hand, a diamond synthesis method using a chemical vapor deposition method (CVD method) is used as a method for introducing nitrogen atoms (for example, a gas containing nitrogen) into the raw material at the same time during the latter diamond synthesis. Unlike ion implantation, this method can introduce nitrogen without causing crystal damage. Furthermore, it is possible to control the incorporation of nitrogen into the vicinity of the surface by controlling the timing of introducing nitrogen during crystal growth. However, since the crystal growth by the CVD method is highly suppressed due to the high quality, the electron beam accelerated to about several MeV after the crystal growth in order to introduce the necessary holes into the NV optical center. Irradiation is performed, and as a result, induction of crystal damage is inevitable as in the case of ion implantation. Further, since crystal growth is performed over the entire surface of the substrate, it cannot be arranged in a desired size and shape in a two-dimensional direction. In particular, the range of highly accelerated electrons cannot selectively stay only on the crystal surface, so that damage is retained throughout the crystal. Therefore, in the above-described current method, it is necessary to newly develop a post-process for suppressing disturbance that affects the quantum performance of the NV optical center, and the potential using diamond cannot be sufficiently extracted.

  As described above, in a solid quantum element or a micro magnetic sensor using the NV optical center of diamond, the NV optical center which is a resource of the element is artificially placed in a desired surface or a space in a crystal with a desired size. However, the current situation is that there is no sufficient solution until now.

  The present invention has been made in view of such a current situation, using a CVD method capable of growing a high-quality diamond single crystal by a method different from the above-described conventional method, a desired surface and a space in the crystal, Diamonds with NV optical centers arranged in size and shape, and NV optical centers that can be placed in the desired surface and crystal space, size and shape automatically during diamond growth without post-processing An object of the present invention is to provide a manufacturing method.

  As a result of intensive studies to achieve the above object, the present inventors have found that the following conditions (1) to (3) are necessary to achieve the above object.

(1) Diamond is homoepitaxial growth by a CVD method using a diamond single crystal as a substrate, and its growth rate is 50 nm / h or less.
Usually, it is possible to reduce the growth rate of diamond by lowering the concentration of diamond raw material, typically methane gas diluted with hydrogen gas, but at the same time, due to the nature of diamond crystal growth, only impurities such as nitrogen In addition, the intake of vacancies is reduced, or the uptake is suppressed to an unobservable level and the crystal quality is improved.

(2) The above-described diamond crystal growth rate is performed when the off-angle of the diamond substrate is 0 ° or more and 0.5 ° or less, and the diamond crystal growth mode is step flow growth.
This realizes a state in which nitrogen and vacancies are not taken in when there is a specific nitrogen content in the environment of diamond crystal growth by CVD. This is because, when the growth rate is slow, the incorporation of impurities and vacancies is reduced, or the incorporation is suppressed to an unobservable level. On the other hand, the growth rate of diamond can be controlled not only by the concentration of the raw material but also by the off-angle of the substrate, and the crystal growth rate increases as the off-angle of the substrate increases (0.5 degree or more). . The step flow growth of diamond maximizes the relationship between the off angle and the growth rate. Increasing the crystallization rate, contrary to the logic described above, increases the nitrogen and vacancies uptake efficiency in the environment. This means that, if the off-angle of the substrate can be locally changed in a desired shape and arrangement, the intake of nitrogen and vacancies can be automatically controlled simultaneously.

(3) A local off-angle change is formed on the substrate with a desired surface and space, size, and shape in the crystal.
This is a process of etching a substrate surface that is designed to have a desired pattern, size, and arrangement by using microfabrication technology based on photo or electron beam lithography and dry etching (to form a fine groove structure). . Since the local off angle changes at the boundary between the etched portion and the non-etched portion, the growth rate of crystal growth is relatively increased in the region portion etched according to the designed pattern, Nitrogen and vacancy uptake are relatively high. In this case, the greater the difference in the off-angle between the etched portion and the non-etched portion, that is, the greater the contrast, the better the effect is obtained, and this necessary condition is a condition for satisfying this.

The present invention has been completed based on these findings, and according to the present invention, the following inventions are provided.
[1] A method for producing a diamond single crystal in which nitrogen-vacancy composite defects are automatically arranged in the crystal surface and / or crystal space during diamond crystal growth by homoepitaxial growth,
A diamond single crystal substrate having an off angle of 0 ° or more and 0.5 ° or less is used as a substrate. After a local off angle change is formed on the substrate, a microwave plasma is used using a source gas containing nitrogen. A method for producing a diamond single crystal in which nitrogen-vacancy composite defects are arranged, wherein the crystal growth rate is controlled to a step flow mode at a crystal growth rate of 50 nm / h or less by a CVD method.
[2] The nitrogen-vacancy composite defect according to [1], wherein the local off-angle change is formed by a fine processing technique using a photo or electron beam lithography method and / or a dry etching method. A method for producing a diamond single crystal in which is arranged.
[3] A substrate made of a diamond single crystal having an off angle of 0 degrees to 0.5 degrees and having a locally formed off angle change;
A diamond single crystal homoepitaxially grown on the substrate,
A diamond single crystal having nitrogen-vacancy complex defects arranged in a desired size and / or shape in a crystal surface or crystal space of the diamond single crystal on the substrate.
[4] The diamond single crystal according to [3], wherein the nitrogen-hole composite defects are regularly arranged.

By using the present invention, a one-dimensional structure, or a zero-dimensional structure (dot shape), and a combination of these, or continuous or intermittent joining, etc. can be applied. A diamond single crystal in which the optical center is arranged in this pattern becomes possible.
In addition, according to the present invention, it is possible to freely design an optimum shape for arranging the NV optical center in the diamond crystal, which was not possible with the conventional method, and to efficiently supply nitrogen and vacancies. For the design, a fine processing technique using a photo or electron beam lithography method and a dry etching method with high reproducibility and processing design accuracy can be used. In addition, since the formation of the NV optical center is performed simultaneously with the growth of the diamond crystal, it is one of the common features of the conventional method, that is, for beam irradiation with electrons or charged particles for vacancy capturing and crystal reconstruction. Since a post-process such as an annealing process is not required, it is possible to maintain a crystal environment that can exhibit excellent characteristics without crystal damage that causes disturbance of the NV optical center.

Lattice model of the nitrogen-hole optical center in diamond crystals. Schematic diagram of off-angle and surface atomic step of (001) plane diamond substrate Explanatory diagram of growth rate in step flow mode Conceptual diagram of lattice model and local off-angle formation when a diamond crystal with an off-angle of 0 is viewed from the <100> direction. The figure which shows an example of the diamond single crystal by which the optical center was arrange | positioned to the one-dimensional structure by the method of this invention The figure which shows the other example of the diamond single crystal by which the optical center was arrange | positioned to the one-dimensional structure by the method of this invention The figure which shows an example of the diamond single crystal by which the optical center was arrange | positioned at the zero-dimensional structure by the method of this invention The figure which shows another example of the diamond single crystal by which the optical center was arrange | positioned at the zero-dimensional structure by the method of this invention The figure which shows an example of the diamond single crystal by which the optical center was arrange | positioned to the zero-dimensional structure (cylinder) by the method of this invention The figure which shows another example of the diamond single crystal by which the optical center was arrange | positioned to the zero-dimensional structure (cylinder) by the method of this invention. The figure which shows an example of the diamond single crystal by which the optical center was arrange | positioned by the method of this invention in the pattern of arbitrary character structures or arbitrary shapes Line and space groove structure formed on (001) plane diamond single crystal substrate Optical microscope image of thin film surface after homoepitaxial growth (a) Observation result by photoluminescence mapping method and (b) its spectrum Region B (a) CL spectrum and (b) CL image

Hereinafter, the method of the present invention will be described in more detail.
The present invention uses a microwave plasma CVD method using a mixed gas of methane gas and hydrogen gas as a raw material, and is realized by diamond by homoepitaxial growth using single crystal diamond as a substrate. Homoepitaxial growth is one of crystal methods that sensitively reflects the crystal structure of a substrate. The present inventors have so far adopted a step flow mode in which a crystal is formed by advancing in a lateral direction of atomic steps existing on the crystal surface by optimizing the growth conditions of diamond using the microwave plasma CVD method. Has succeeded.

  In the present invention, the most important point is that diamond is formed by homoepitaxial growth and the growth mode is controlled to the step flow mode. The reason for this is that the incorporation of impurities and vacancies strongly depends on the growth rate, depending on the growth and characteristics of diamond, and the growth rate is constant when the concentration of methane gas (methane / hydrogen mixture ratio) as the source gas is constant , Strongly depends on the step density of the substrate.

FIG. 3 is a diagram for explaining the growth rate in the step flow mode. The growth rate in the step flow mode is given by the following equation.
V = R cos θ (1)
Here, R represents the growth rate in the direction perpendicular to the atomic layer, and is represented by R = pv, that is, the product of the step speed v and the step density p.
The step density p is estimated by p = h / λ = tan θ, that is, the ratio of the step height (h) to the step terrace width (λ). θ represents the off-angle of the substrate (the difference in tilt between the crystallographic atomic plane and the actual surface).

Therefore, it is shown that the growth rate increases as the step density of the substrate increases, that is, as the off-angle of the substrate increases. In other words, if this change in off-angle can be locally formed on the substrate, it means that the growth rate in that portion can be increased. Then, by adding a specific amount of nitrogen to the diamond synthesis gas, it is possible to automatically and locally incorporate nitrogen and vacancies. At this time, by using a substrate having as small an off-angle as possible (less than 0.5 degrees) as a base, the growth rate contrast between the part where the off-angle is locally changed and the other part is maximized. be able to.
FIG. 4 shows a conceptual diagram of the lattice model and local off-angle formation when a diamond crystal with an off-angle of 0 is viewed from the <100> direction. In the figure, the horizontal straight line indicates the atomic plane, and the upper part of the curve indicates the portion that has been etched away. When the diamond surface is etched locally according to the curve, 46 atomic steps are possible. Show.

In order to form local off-angle changes on the substrate, the micro-fabrication technology of diamond by photo or electron beam lithography and dry etching is used, and the surface of the substrate designed to have a desired pattern, size and arrangement can be obtained. Etching is preferably performed.
After a desired pattern is formed on the substrate surface, a diamond single crystal is homoepitaxially grown on the substrate on which the pattern is formed.

Synthesis of diamond thin film includes microwave plasma CVD (frequency 915MHz, 2.45GHz, etc.) method, hot-filament method, electron assisted method, Plasma Torche method, Electron Cyclotron Resonance (ECR) All chemical gases such as the DC method, DC discharge plasma method, RF plasma method, RF induction thermal plasma method, DC plasma jet method, combustion flame method, etc. Although it can be carried out by a phase deposition method, in the present invention, it is preferable to use a microwave plasma CVD method with less impurity incorporation.
In addition, as a raw material gas for synthesizing diamond, all gases including carbon such as methane gas, carbon dioxide, and carbon monoxide are targets of diamond raw material gas. In the present invention, methane gas (CH ₄ ) is usually used as a raw material. To do. At this time, an isotope-enriched diamond thin film can be realized by changing the carbon (C) of methane gas into ¹² CH ₄ gas and ¹³ CH ₄ gas that are isotope-purified.
The growth rate of diamond is set to 50 nm / h or less by adjusting the flow rate of these methane gases which are source gases.
Further, in order to form the NV optical center, any time and timing and any flow rate can be obtained by using nitrogen (N ₂ ) gas, isotope-purified ¹⁴ N ₂ gas or ¹⁵ N ₂ gas, or source gas containing them. To mix.

In this way, the diamond single crystal structure in which the NV optical center is arranged on the crystal surface uses a single crystal diamond substrate synthesized at a high pressure and a high temperature on the substrate, and a pattern such as a desired groove structure is formed on the substrate. Obtained by homoepitaxial growth.
The diamond single crystal structure in which the NV optical center is arranged in the crystal is obtained by forming the NV optical center on the crystal surface of the diamond single crystal as described above, and then purifying the nitrogen (N ₂ ) gas or the isotope purification. Instead of the ¹⁴ N ₂ gas or ¹⁵ N ₂ gas or the raw material gas containing them, the raw material gas not containing these gases is used for subsequent homoepitaxial growth.

FIG. 5 shows an example of a diamond single crystal structure in which the NV optical center is arranged by using the present invention. FIGS. 5 (a) and 5 (b) show a one-dimensional structure, FIG. c) to (f) are 0-dimensional structures (including dot shapes), and FIG. 5G is a combination of these, or an arbitrary character structure or an arbitrary figure pattern applying continuous or intermittent joining. Is shown.
In the figure, regarding the size of the groove structure or the concave structure, W ₁ , W ₂ , L ₁ , and L ₂ can be arbitrarily scaled. Further, D, D ₁ , L 1 and φW ₁ are desirably 10 μm or less, and D ₂ is desirably 0.5 nm to 100 nm. However, the size described above can be exceeded by changing and optimizing the growth conditions.

  In order to verify the above-described method of the present invention, a fine processing technique using an electron beam lithography method and a dry etching method is used, and on a diamond single crystal substrate having an off angle of 0.5 degrees evaluated by X-ray diffraction, In this manner, a line (etched portion = groove portion) & space (unetched portion) groove structure parallel to the crystal <110> orientation was produced. An electron beam lithography apparatus was used for pattern production on the surface. In order to synthesize high-quality diamond thin films with low defects, single crystal diamond synthesized at high pressure and high temperature was used for the substrate. At this time, single-crystal diamond synthesized at high pressure and high temperature, that is, the diamond surface immediately after purchase, is usually mechanically polished, so there are polishing scratches and marks on the surface. A diamond substrate having a surface roughness Ra <40 nm or less repolished by Skyf polishing was used.

The mask on which the pattern was formed was placed on the diamond single crystal substrate, and a rectangular groove structure was formed by an ICP (Inductively Coupled Plasma) etching process using oxygen gas and carbon tetrafluoride gas. FIG. 6 shows a pattern processed on the diamond surface.
After the four patterns shown in FIG. 5 were formed on the substrate surface, a diamond single crystal was homoepitaxially grown on the substrate having this groove structure by the method described below.

For epitaxial growth using the microwave plasma CVD method, an end launch type microwave plasma CVD apparatus having a stainless steel reaction vessel that has a small amount of impurity incorporation and can be stably operated is used. The apparatus mainly includes a microwave power source, a reaction vessel, a substrate temperature control system, a source gas supply system, and a vacuum exhaust system. Here, the microwave power unit uses a magnetron with a maximum output of 1.5 kW and a frequency of 2.45 GHz.
In addition, as a raw material gas for synthesizing diamond, all gases including carbon such as methane gas, carbon dioxide, and carbon monoxide are targets of diamond raw material gas. In the present invention, methane gas (CH ₄ ) is usually used as a raw material. . At this time, an isotope-enriched diamond thin film can be realized by changing the carbon (C) of methane gas into ¹² CH ₄ gas and ¹³ CH ₄ gas that are isotope-purified.

Prior to setting the diamond substrate in the substrate reaction vessel, the surface of the diamond substrate is removed by heating and washing with sulfuric acid, hydrofluoric acid, ultrasonic cleaning with an organic solvent, and ultrapure boiling cleaning. Next, the cleaned diamond substrate is set on the stage in the reaction vessel, the inside of the reaction vessel is kept at a vacuum level of 10 ⁻⁸ Torr, and the carbon-based residual gas is 10 ⁻⁹ Torr or below the detection limit by a partial pressure gauge. Make sure that

As raw materials for synthesizing the diamond thin film, commercial-grade high-purity hydrogen gas and high-purity methane gas or isotope-purified high-purity methane gas are used. These gases are uniformly mixed by a manifold in a state where the flow rate is controlled by a mass flow controller, and the mixed gas is introduced into the reaction vessel as a gas shower from a shower head above the reaction vessel of the diamond synthesizer. At this time, the gas ratio typically mixed is 99.85% hydrogen and the remaining 0.15% methane. At this time, since the mixing ratio of methane to hydrogen gas is one of the factors that determine the growth rate of the diamond thin film, the flow rate of methane gas is adjusted so that the growth rate of diamond is 50 nm / h or less.
On the other hand, in order to suppress the influence of residual carbon in the hydrogen gas that occupies most of the gas, the hydrogen gas is carbon monoxide (CO) immediately before mixing with methane gas by a hydrogen purifier using a platinum catalyst chemical adsorption method. Hydrogen gas having a purity of 99.99999% from which residual impurities in hydrogen gas such as carbon dioxide (CO ₂ ) and hydrocarbon (CH ₄ etc.) are removed is used.

Thereafter, the above-described mixed gas is introduced into the reaction vessel and synthesized under the following conditions. Typical synthesis parameters are a substrate temperature of 800 ° C., a microwave power of 750 W, a total gas pressure of 25 Torr, a total gas flow rate of 400 SCCM, and a hydrogen / methane mixture ratio of 0.15%. Here, the thickness of the diamond thin film is controlled by the synthesis time since the growth rate of diamond is known.
To form the NV optical center, nitrogen (N ₂ ) gas or isotope-purified ¹⁴ N ₂ gas or ¹⁵ N ₂ gas or a gas containing them is mixed at an arbitrary time and timing and at an arbitrary flow rate. . Here, the mixing ratio of nitrogen N to methane gas was adjusted to 2% or less.

FIG. 7 shows an optical microscope image of the thin film surface after homoepitaxial growth.
In the figure, A to D indicate the structure corresponding to the structure width of the four patterns shown in FIG. 6 (A = 1 μm, B = 5 μm, C = 0.5 μm, D = 2 μm), E is A normal epitaxial surface is shown.
A normal epitaxial surface E region (region not subjected to etching treatment) shows a surface structure by macro step bunching peculiar to step flow growth, whereas a surface on a fine structure has an irregular step bunching structure. Is suppressed, smoothness is improved in any region, and a growth mode in which macro steps parallel to the groove structure are seen is obtained. In addition, for a growth design with a film thickness of 500 nm, a groove portion having a depth of 2 μm is completely covered, and the growth rate of the groove portion is locally 4 times or more higher than that of a normal epitaxial surface (E region). It was confirmed that it was realized.

The confirmation of the NV optical center was evaluated by a photoluminescence mapping method using a confocal microscope system. In the NV optical center, when one electron is held, light emission having a zero phonon line at 637 nm is observed.
FIG. 8A shows the result of photoluminescence mapping from each pattern structure. The observation area is 80 μm × 80 μm, and the resolution is 0.2 μm. As shown in the figure, luminescence localized in the groove structure was observed from any line and space.
FIG. 8B shows an example of spectral analysis of this luminescence. From this result, it is shown that the origin of light emission localized in the groove structure is the NV optical center holding one electron.

Next, in order to evaluate the quality of the thin film with the pattern structure, the emission in the band edge region was observed by the cathodoluminescence method.
FIG. 9 is a diagram showing the observation result of the region B. The observation basin is 190 μm × 190 μm and the observation temperature is 80K.
FIG. 9A shows an example of the cathodoluminescence image from the pattern region and its emission intensity distribution (line profile). The bright part of the image shows light emission from the visible light range. Similar to the result of photoluminescence mapping, light emission localized in the groove structure is observed.
FIG. 9B shows a cathodoluminescence spectrum from the pattern region. As shown in the figure, light emission from free exciton having a sharp peak at 235 nm is observed. This light emission is the original light emission of high-quality diamond with few defects and impurities, and is used as an index for quality evaluation. It is noted here that light emission having a peak at 575 nm is simultaneously observed. This peak is emitted from the NV optical center where no electrons are captured. The cathodoluminescence method has high sensitivity to the so-called empty NV optical center because the energy of the electron beam used for excitation is large.
This result shows that the NV optical center can be artificially formed in a desired arrangement while maintaining a high quality diamond environment by the CVD method. That is, the NV optical center is spatially independent in the diamond crystal.

  While realizing high-quality diamond crystal growth using the CVD method, the desired surface space is automatically obtained by utilizing the crystal growth properties of diamond, despite the fact that nitrogen is added to the source gas. It was shown that size, shape, and arrangement of diamonds can be made freely. This can be said to experimentally demonstrate the method of the present invention.

The diamond incorporating the NV optical center of the present invention and the manufacturing method thereof are adapted to high-quality elements and forming techniques required for next-generation information processing technologies such as nanoscale magnetic sensors, quantum cryptography communication, and quantum computers. be able to. In addition, by applying the present technology, for example, by changing the incorporated atoms, various optical centers can be formed. As a result, it is possible to detect the light emission pattern from the state where the light emission peculiar to the optical center, that is, the light emission having a different emission wavelength (color) is arranged according to the desired design, and the light propagation can be controlled. It can be applied to photonic crystals with diamond.
In recent years, diamond synthesized by the CVD method has attracted attention as a resource to replace natural diamond, but at that time, it is difficult to determine the manufacturer from the viewpoint of diamond identification and identification. Sometimes, by using the present invention, it is possible to insert it as a hidden character, so that it can be used as a new tag technology that can identify whether it is a manufacturer's diamond or not.

1: Region where NY optical center is formed 2: Diamond single crystal

Claims (4)

A method for producing a diamond single crystal in which nitrogen-vacancy composite defects are automatically arranged in a crystal surface and / or crystal space during crystal growth of diamond by homoepitaxial growth,
A diamond single crystal substrate having an off angle of 0 ° or more and 0.5 ° or less is used as a substrate. After a local off angle change is formed on the substrate, a microwave plasma is used using a source gas containing nitrogen. A method for producing a diamond single crystal in which nitrogen-vacancy composite defects are arranged, wherein the crystal growth rate is controlled to a step flow mode at a crystal growth rate of 50 nm / h or less by a CVD method.   2. The nitrogen-vacancy composite defect according to claim 1, wherein the formation of the local off-angle change is performed by a microfabrication technique using a photo or electron beam lithography method and / or a dry etching method. A method for producing a diamond single crystal. A substrate made of a diamond single crystal having an off angle of 0 degrees to 0.5 degrees and having a locally formed off angle change;
A diamond single crystal homoepitaxially grown on the substrate,
A diamond single crystal having nitrogen-vacancy complex defects arranged in a desired size and / or shape in a crystal surface or crystal space of the diamond single crystal on the substrate.   The diamond single crystal according to claim 3, wherein the nitrogen-vacancy composite defects are regularly arranged.

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