Method for synthesizing nitrogen-containing materials by decomposition of lithified nitrogen-containing precursors

Abstract

A method for synthesizing a nitrogen-containing material, comprising: mixing a nitrogen-containing lithiumization precursor with at least one element other than lithium and nitrogen to obtain a mixed composition; placing the mixed composition in an apparatus; supplying nitrogen gas to the apparatus; and heating the apparatus under high temperature and high pressure for a predetermined time to obtain the nitrogen-containing material.

Description

Technical Field

[0001] Cross - reference to related applications This application claims priority based on U.S. Provisional Patent Application No. 63 / 497,027, filed on April 19, 2023, the entire content of which is hereby incorporated by reference in its entirety into this specification.

[0002] The present disclosure relates to a method for synthesizing nitrogen - containing materials, and more particularly, to a method for growing nitrogen - containing single crystals by decomposing lithiated nitrogen - containing precursors.

Background Art

[0003] Semiconductor materials are useful in many electronic device applications due to their excellent physical properties. However, when synthesizing these materials in large quantities, problems arise due to equipment requirements and associated costs.

[0004] Therefore, those skilled in the art continue to conduct research and development in the field of synthesizing nitrogen - containing materials such as semiconductor materials.

Summary of the Invention

[0005] This summary is only intended to briefly introduce some aspects of one or more embodiments of the present disclosure. Further application areas of the present disclosure will become apparent from the detailed description below. This summary does not provide a comprehensive overview, nor is it intended to identify important or decisive elements of the present teachings or to limit the scope of the present disclosure. Rather, its purpose is to present one or several concepts in a simplified form as a prelude to the detailed description that follows.

[0006] Currently, the growth of GaN, AlN, and BN single crystal materials is limited to small sizes due to various material constraints. To meet the industrial demand for these materials, it is necessary to grow larger boules. Therefore, the present disclosure provides an economic solution for synthesizing these materials as boules on a larger scale while maintaining the desired material properties.

[0007] The present disclosure relates to a method for synthesizing nitrogen-containing materials.

[0008] The method of the present disclosure includes a step of mixing a lithium-containing precursor with at least one element other than lithium and nitrogen to obtain a mixed composition, a step of disposing the mixed composition in a device, a step of supplying nitrogen gas into the device, and a step of heating the device under a predetermined high temperature and high pressure for a predetermined time to obtain a nitrogen-containing material.

[0009] As an example, the lithium-containing precursor may include a binary nitride. As an example, the lithium-containing precursor may include a ternary nitride. As an example, the mixed composition may include at least one ternary or higher lithium nitride compound. As an example, the lithium-containing precursor includes one or more of Li3N, Li3BN2, Li3GaN2, or Li3AlN2. As an example, the mixed composition includes one or more of Li3BN2, Li3GaN2, or Li3AlN2.

[0010] As an example, at least one element other than lithium and nitrogen may include gallium, aluminum, or boron. As an example, at least one element other than lithium and nitrogen may include an element or material that is in a liquid phase under process conditions or dissolved in a flux, and the material may include at least one flux modifier selected from hydrogen, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, lead, tin, antimony, indium, and bismuth. As an example, the mixed composition includes nitrides.

[0011] As an example, the method further includes a step of adding an impurity or a dopant to the mixed composition, and the impurity or dopant includes one or more of carbon, sulfur, silicon, germanium, oxygen, beryllium, zinc or magnesium. As an example, the nitrogen-containing material is GaN. As an example, the nitrogen-containing material is BN. As an example, the nitrogen-containing material is AlN.

[0012] As an example, the mixed composition has a nitrogen content exceeding 1 at% N, exceeding 5 at% N, or exceeding 10 at% N. As an example, the nitrogen-containing material is AlGaN, AlBN, BGaN or BAlGaN, and the ratios of Al, Ga and B are arbitrary. As an example, the nitrogen-containing material is Al x Ga 1-x N, Al x B 1-x N, B x Ga 1-x N, or B x Al y Ga 1-x-y N, where x or y is 0 or more and 1 or less. As an example, the nitrogen-containing material contains a controlled amount of dopant or impurity. As an example, the nitrogen-containing material is a single crystal. As an example, the nitrogen-containing material is a single crystal boule with a diameter or width of at least 1 cm, at least 5 cm, or at least 10 cm.

[0013] As an example, the device is an autoclave. As an example, the high temperature ranges from about 800 °C to about 1600 °C. As an example, the high pressure ranges from about 0.1 MPa to about 100 MPa.

[0014] As an example, the method includes placing the mixed composition in a crucible and placing the crucible in an autoclave before heating. As an example, the crucible is placed in the vicinity of a heating device in the device. As an example, the crucible includes one or more of B, C, N, O, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, or Re.

[0015] As an example, the method includes pressurizing the apparatus with nitrogen gas at room temperature for a predetermined time to a pressure in the range of 0.1 MPa to 100 MPa, and then reducing the pressure to a range of 0.1 MPa to 10 MPa either thereafter or immediately before heating. As an example, the apparatus is pressurized for a predetermined time ranging from approximately 20 minutes to approximately 24 hours.

[0016] As an example, the method includes the step of adding at least one flux modifier to the mixed composition. As an example, the method includes the step of separating nitrogen-containing material from the by-products.

[0017] Alternatively, a method is provided in which a molten material is supplied into the apparatus, and a nitrogen-containing lithium-ion precursor is passed through the molten material for a predetermined time to obtain a nitrogen-containing material.

[0018] For example, the apparatus is pressurized under N2 at 1 atmosphere. For example, the molten material includes one or more of aluminum, gallium, boron, sodium, potassium, cesium, lead, tin, antimony, and indium. For example, the apparatus is heated to a range of approximately 800°C to approximately 1600°C. For example, the lithiumization precursor includes a binary nitride. For example, the lithiumization precursor includes one or more ternary nitrides. For example, the lithiumization precursor includes one or more of Li3N, Li3BN2, Li3GaN2, or Li3AlN2. For example, the nitrogen-containing material is GaN. For example, the nitrogen-containing material is BN. For example, the nitrogen-containing material is AlN.

[0019] For example, a nitrogen-containing material is Al x Ga 1-x NI, Al x B 1-x N, B x Ga 1-x N or B x Al y Ga 1-x-yN is the nitrogen atom, and x or y is between 0 and 1. For example, the nitrogen-containing material contains a controlled amount of dopant or impurity. For example, the nitrogen-containing material is a single crystal. For example, the nitrogen-containing material is a single-crystal boule with a diameter or width of at least 1 cm, at least 5 cm, or at least 10 cm. For example, the apparatus is an autoclave.

[0020] Another method is provided, which involves supplying a nitrogen-containing lithium material and a non-lithium material into a device, and heating the device to a temperature exceeding the decomposition temperature of the nitrogen-containing lithium material under at least 1 atmosphere of N2 for a predetermined time to obtain a nitrogen-containing material.

[0021] For example, the lithiumization precursor includes a binary nitride. For example, the lithiumization precursor includes a ternary or higher nitride. For example, the lithiumization precursor includes Li3N, Li3BN2, Li3GaN2, or Li3AlN2. For example, the nitrogen-containing material is Al x Ga 1-x NI, Al x B 1-x N, B x Ga 1-x N or B x Al y Ga 1-x-y N is the element, and x or y is between 0 and 1. For example, nitrogen-containing materials contain controlled amounts of dopants or impurities. For example, non-lithium materials contain dissolved elements. For example, non-lithium materials contain reactive materials.

[0022] For example, the nitrogen-containing material is GaN. For example, the nitrogen-containing material is BN. For example, the nitrogen-containing material is AlN. For example, the nitrogen-containing material is a single crystal. For example, the nitrogen-containing material is a single-crystal boule with a diameter or width of at least 1 cm, 5 cm, or 10 cm. For example, the apparatus is an autoclave.

[0023] The nitrogen-containing single crystal contains GaN, has a diameter or width of at least 50 mm, and a length-to-diameter ratio of at least 1:1. For example, the single crystal has a lattice curvature greater than 100 m and a diameter or width greater than 1 cm. For example, the single crystal material is Boolean. For example, the single crystal is synthesized via a nitrogen-containing lithium material. For example, the single crystal contains a controlled amount of dopant or impurity.

[0024] The nitrogen-containing single crystal contains AlN, has a diameter or width of at least 50 mm, and has a length-to-diameter ratio of at least 2:1.

[0025] For example, the single crystal has a lattice curvature greater than 100 m and a diameter greater than 1 cm. For example, the single crystal material is Boolean. For example, the single crystal is synthesized via a nitrogen-containing lithium material. For example, the single crystal contains a controlled amount of dopant or impurity.

[0026] The nitrogen-containing single crystal contains BN, has a diameter or width of at least 10 mm, and has a length-to-diameter ratio of at least 1:2.

[0027] For example, the single crystal has a lattice curvature greater than 100 m and a diameter or width greater than 1 cm. For example, the single crystal material is Boolean. For example, the single crystal is synthesized via a nitrogen-containing lithium material. For example, the single crystal contains a controlled amount of dopant or impurity. For example, the nitrogen-containing single crystal has at least 100%, at least 99%, or at least 95% hexagonal, wurtzite, cubic, or rhombohedral phases. [Brief explanation of the drawing]

[0028] [Figure 1] This graph shows the decomposition pressure of Li3N as a function of temperature.

[0029] [Figure 2] This is a schematic diagram of a system for synthesizing nitrogen-containing materials.

[0030] [Figure 3] This graph shows the equilibrium vapor pressure of lithium on pure lithium.

[0031] [Figure 4] This is a schematic diagram of the autoclave used in the method disclosed herein.

[0032] [Figure 5] This is a scanning electron microscope image of an hBN crystal grown by the method disclosed herein.

[0033] [Figure 6] Figure 5 is a scanning electron microscope image of a portion of the hBN crystal.

[0034] [Figure 7] Figure 5 shows a series of energy-dispersive X-ray spectroscopic images of boron and nitrogen in the hBN crystal.

[0035] [Figure 8] Figure 5 shows the X-ray diffraction measurement results for the hBN crystal.

[0036] [Figure 9] Figure 5 shows the Raman scattering spectrum of the hBN crystal.

[0037] [Figure 10] This is the result of X-ray diffraction measurement of a GaN crystal. [Modes for carrying out the invention]

[0038] A more detailed explanation of this disclosure will be easier to understand by referring to the attached drawings. However, it should be understood that this disclosure is not limited to the exemplary configurations and apparatus shown in the drawings.

[0039] To illustrate the principles of this disclosure, various examples are described below. While specific embodiments are described, those skilled in the art will readily understand that the same principles are equally applicable to other applications and methods. This disclosure is not limited to the details of specific embodiments. Terms used herein are for illustrative purposes only and are not intended to limit this disclosure or its applications or uses.

[0040] In this specification and the appended claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly indicates otherwise. The singular form of a classification of components includes not only one chemical species within that classification but also mixtures of those chemical species. "a (or an)," "one ormore," and "at least one" are interchangeable. "Comprising," "including," "containing," and "having" are also interchangeable. "Include" should be interpreted as meaning "includement that is not limited to this," and "including" should also be interpreted as meaning "includement that is not limited to this."

[0041] Throughout this specification, the term "range" is used as a simplified description of each value within that range. Any value within that range can be selected as an endpoint of the range. Therefore, the ranges of values ​​disclosed herein are illustrative and include all values ​​and subranges between them.

[0042] Unless otherwise specified, all percentages and amounts expressed elsewhere in this specification and description shall be understood to mean weight percentages relative to the total weight of the composition. Unless otherwise specified, the statement “present in weight %” means a percentage based on the total dry weight of the composition. “Based on the dry weight of the composition” means based on the total dry weight of the composition in a dry state containing less than 5.0% by weight of the solvent, preferably less than about 0.5% by weight, and more preferably less than about 0.25% by weight. For example, “dry state” refers to a composition having a solids content of about 95%, about 98%, preferably about 99%, and more preferably about 100%. In contrast, unless otherwise specified, the statement “based on wet weight” means a percentage based on the total weight of the composition containing at least 5% by weight of the solvent.

[0043] In this application, the term "about" means a value that includes a range of ±5% from the stated numerical value. Furthermore, in this specification, "substantially not present" means an amount in the composition that is less than about 5.0% by weight, less than about 3.0% by weight, less than about 1.0% by weight, preferably less than about 0.5% by weight, and more preferably less than about 0.25% by weight.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as that commonly understood by a person of ordinary skill in the art. All patents, patent applications, publications, and other documents cited or referenced herein are incorporated by reference in their entirety for any purpose. In the event of any conflict between the definitions in this disclosure and the definitions in the referenced documents, the definitions in this disclosure shall prevail.

[0045] Any references to direction or orientation in the descriptions of the embodiments disclosed herein are intended solely for illustrative purposes and are not intended to limit the scope of this disclosure in any way. Relative terms such as “down,” “up,” “horizontal,” “vertical,” “upward,” “downward,” “up,” “top,” and “bottom” (and their derivatives such as “horizontally,” “downward,” “upward”) are to be interpreted as referring to the orientation described at that time or shown in the drawings under consideration (if applicable). These relative terms are for illustrative purposes only and do not require the apparatus to be configured or operated in a particular orientation unless otherwise specified.

[0046] In this specification, terms such as “attached,” “affixed,” “connected,” “coupled,” and “interconnected” refer to a relationship in which structures are fixed or attached to each other directly or indirectly, even through an intervening structure, and include both movable and rigid attachments / relationships, unless otherwise specified. Accordingly, this disclosure is not limited to examples illustrating specific combinations of features that may exist alone or in combination with other features.

[0047] This specification discloses a method for synthesizing nitrogen-containing materials. This method involves growing nitrogen-containing single crystals (e.g., gallium nitride (GaN), boron nitride (BN), aluminum nitride (AlN)) using nitrided lithium precursor materials. This method utilizes the controlled decomposition of nitrogen-containing lithium precursors to result in the synthesis of nitrogen-containing materials.

[0048] Nitrogen-containing materials, including nitrides, oxynitrides, and carbonitrides, can be useful in forming materials with advantageous material properties. For example, GaN, a wide-bandgap semiconductor, is used in the manufacture of blue (white) LEDs and lasers, as well as in the operation of power electronics / RF devices. AlN can be useful in UV optoelectronics (sterilization, curing, etc.). BN, particularly in its hexagonal form, can be useful in the development of 2D device technology, and in its cubic form, as a superhard material with outstanding thermal conductivity, and further useful in power electronics / RF devices based on its unique properties.

[0049] Synthesizing the above materials in large quantities presents challenges not only due to the required costs but also because of their property of readily decomposing at certain temperatures prior to melting (for example, GaN decomposes into Ga metal + N2 gas). Furthermore, synthesizing ternary alloys like AlGaN in forms larger than thin films or in powder form involves complexities regarding commercial feasibility.

[0050] Nitride anions in nitrides (N 3- ) imparts unique electronic and bonding properties to nitride materials that are difficult to achieve in other chemical spaces, making nitrides a very attractive area from a materials design perspective. These properties, along with useful (opto)electronic properties and defect resistance, result in strong metal-nitrogen bonds for structural stability and mechanical rigidity. With appropriate material selection and design, solid-state lighting (e.g., In x Ga 1-x N, Sr[LiAl3N4]:Eu 2+ ), superconductors (e.g., CaTaN2), ammonia synthesis catalysts (e.g., Fe3Mo3N, Co3Mo3N, Ni2Mo3N), topological materials (e.g., MgTa 2-x Nb xSignificant progress and breakthroughs have been achieved in areas such as N3. From a computational science perspective, numerous novel and interesting nitride and related material systems with attractive material properties are predicted. For example, regarding thermodynamically stable pure nitride perovskites, LaWN3 has ferroelectric polarization comparable to or exceeding that of harmful lead titanate, LaMoN3 exhibits degenerate p-type doping by Sr doping, which is rare in nitride semiconductors, and NdReN3 or DyReN3 are the latest Nd-based high-performance magnets (i.e., Nd2Fe 14 It is predicted that these materials will have magnetization comparable to or exceeding that of B). Since all of these materials are perovskites, they are expected to have a wide degree of freedom to adjust their properties by cationic substitution, similar to oxides.

[0051] The methods of this disclosure provide suitable synthesis processes. Typical processes require the addition of a reactive form of nitrogen (plasma, ammonia, or precursors such as azides (NaN3), amides (NaNH2), or nitrides (Ca3N2)) to the system. By heating (and sometimes pressurizing), the nitrogen is transferred to the element of interest, thereby forming a nitride. This usually arises from a solid or gas phase. While these techniques have been successfully applied to nitrides to date, even if nitrides can be synthesized, there are two significant drawbacks. Namely, the material is usually a polycrystalline solid with many defects where grain boundaries are abundant and negatively affect the intrinsic material properties, or a thin film deposited on a substrate, resulting in a strained polycrystalline or defective film. Self-supporting single-crystal materials of sufficient quality for proper material characterization are generally limited to a few millimeters in size due to the limitations of synthesis equipment.

[0052] With the emergence of wide-bandgap GaN in the early 1990s, attention focused on developing and improving synthetic routes for growing large volumes of single-crystal nitrides to maximize its unique properties. The most promising and practical methods follow two strategies: one involves supplying high concentrations of metal halides and ammonia in the gas phase to achieve growth rates exceeding 1 cm per day (e.g., hydride vapor deposition (HVPE)), and the other involves dissolving elements in nitrogen-rich solvents (supercritical ammonia) and crystallizing each nitride (e.g., ammothermal processes). While both methods have shown success, they may have limitations in terms of thermodynamic or kinetic flexibility to offer significantly new synthetic opportunities for crystalline multi-component nitrides.

[0053] One approach to nitride growth is to use sodium as a flux. Sodium does not form nitrides at high temperatures (T), and therefore acts as a nitrogen medium, enabling nitride growth. Nevertheless, large single crystals (>1 mm) 3 The synthesis of ) requires the continuous dissolution and transport of nitrogen in the molten material, which is usually far below 1 at%N (for example, 10 in pure Na). -11 This is extremely difficult due to the presence of nitrogen (at%N). As a result, nitrogen supply is effectively blocked, and significant growth cannot be obtained. A notable exception to this behavior found so far is GaN, which is formed from a unique Na-Ga liquid with unusually large voids that allow nitrogen to dissolve more easily, resulting in a nearly six-order-of-magnitude increase in solubility (0.01 at%N). This has enabled the synthesis of large-sized GaN crystals of high purity and outstanding quality, a remarkable achievement that clearly demonstrates that large-diameter growth of high-purity single-crystal nitrides can arise from flux-based systems.

[0054] While maintaining the simplicity and flexibility of the flux-based approach, another nitride synthesis approach involves using a novel flux that inherently has high nitrogen solubility and is independent of the components present in the flux. Lithium (Li) readily nitrides, forming Li3N even under ambient conditions, resulting in a flux of 25 at%N. Furthermore, Li is known to form ternary nitrides with more than 32 elements (including B, Al, Ga, and In), and computational science predicts additional nitrides, suggesting that at least finite solubility exists for a wide range of elements in this flux system.

[0055] A key factor in successful material synthesis is the ability to liquefy the Li flux while maintaining a Li:N=3:1 stoichiometric ratio, thus avoiding the presence of potentially undesirable reactive non-nitride compounds during melting. Conventional studies using Li3N as a flux typically employed either isothermally maintained sealed ampoules or nitrogen (or near-nitrogen) atmosphere Czochralski pulling apparatuses. Pure Li3N melts at 813°C and decomposes (2Li3N (l) →6Li (l) + N 2(g) It is estimated that a nitrogen pressure of at least 0.6 atm is required to prevent decomposition. The experimentally measured decomposition pressure of Li3N can be extrapolated assuming that there is little change in the formation enthalpy (166 kJ / mol-Li3N) and entropy (120.6 J / mol·K) of Li3N, and the results are shown in Figure 1. This extrapolation shows that pure Li3N molten material can be stabilized up to approximately 1000°C at 100 atmospheres of N2, and up to 1060°C at 1000 atmospheres of N2. Since the boiling point of pure lithium is approximately 1330°C with N2 at 1 atmosphere, its vapor pressure contribution to the total system pressure can be ignored from the standpoint of pressure design. Therefore, it was found that using Li3N as a liquid nitride under superatmospheric pressure to eliminate its decomposition and the formation of undesirable nitrogen-deficient Li3N-Li molten material is useful for the synthesis of nitrogen-containing materials. Note that although Figure 1 shows up to 100°C, growth is also possible under conditions exceeding 1200°C and 100 atmospheres. For example, the method of this disclosure may utilize pressurization up to 4000 atmospheres.

[0056] The method of this disclosure may be carried out in a corrosion-resistant crucible 200 capable of holding the molten material (see Figure 4). As an example, the method is carried out in a crucible 200 containing tungsten (W). The dissolution rate of tungsten and the formation of the resulting LiWN2 may be accelerated by oxygen contamination in the system, thus suggesting that a high-purity system is preferable.

[0057] As another example, the method of this disclosure is carried out in a crucible 200 containing one or more of Mo, Nb, Ta, Fe, Re, TiC, ZrC, BN, Ti, Zr, ZrN, ZrBN, and Cr3C2. At high temperatures (>800°C), materials successfully used with Li or Li3XN2 (X=B, Al, Ga) include Mo, Nb, Ta, Fe, Re, TiC, ZrC, BN, and Cr3C2, with BN and W in particular showing stability for all three proposed ternary systems. When growing nitrides on a large scale from alkali metal flux that does not have a sufficient solid nitrogen source (in compound form), nitrogen addition from the gas phase is required. This requires an open system for a continuous supply of nitrogen, while being a closed system to prevent the release of alkali metal vapor and rapid depletion of the alkali metal flux. All these processes are carried out in a pressurized chamber with a pressure of less than 100 atmospheres and a crucible temperature of up to approximately 1000°C.

[0058] Accordingly, the present disclosure provides a method for synthesizing nitrogen-containing materials from a molten bath of lithified nitrogen-containing precursors under industrially feasible and scalable conditions. The method of the present disclosure is carried out at a pressure of approximately 100 atmospheres or less and a temperature of over 800°C. In one embodiment, the present disclosure provides a means for growing nitride single crystals via controlled decomposition of a nitrogen-containing precursor on a selectively heated surface immersed in a molten body.

[0059] In one or more examples, the method of the present disclosure includes the step of supplying a lithium-nitrided flux. For example, the lithium-nitrided flux includes Li3N. Li3N requires a temperature above about 813°C and a nitrogen gas pressure above about 0.6 atmospheres to prevent decomposition and stabilize it for use in an apparatus (e.g., an autoclave).

[0060] In one or more examples, the method includes the step of mixing a lithium nitride flux with a soluble element such as a metal or metalloid material. One example includes the step of mixing a lithium nitride flux with gallium. Mixing a lithium nitride flux with a soluble element such as gallium forms a lithium precursor. For example, mixing with gallium forms the lithium precursor Li3GaN2. The resulting lithium precursor can be destabilized by raising the temperature above the decomposition / stabilization temperature of the compound. Raising the temperature above the decomposition / stabilization temperature reduces the partial pressures of lithium and / or nitrogen, resulting in the destabilization of the resulting compound.

[0061] In one or more examples, the method may include a step of exposing a nitrogen-containing lithiumization precursor to a suitable combination of temperature and partial pressure conditions to decompose the precursor into a nitride material (e.g., GaN) and a nitrogen-containing lithium compound (e.g., Li3N). It has been observed that maintaining a high nitrogen gas concentration in the autoclave favorably stabilizes the desired nitride material (GaN, AlN, BN). It has also been observed that a low lithium vapor pressure promotes the destabilization of the lithiumization precursor material.

[0062] As an example, the method includes the step of mixing a nitrogen-containing lithiumization precursor with at least one element other than lithium and nitrogen (e.g., a metal or metalloid) to obtain a mixed composition. The nitrogen-containing lithiumization precursor may contain a binary nitride or a ternary nitride. The lithiumization precursor may contain Li3N, Li3BN2, Li3GaN2, or Li3AlN2.

[0063] The amount of lithium required for this method depends on the amount of nitrogen in the system and can also be determined based on the presence of binary, ternary, or higher-order nitrides. For example, lithium may be present in the form of 1 at%Li or 10 at%Li. As another example, when using a ternary compound, lithium may be present in the ratio of 25 at%Li or 33 at%Li. As yet another example, lithium may be present in the ratios of 75 at%Li and 50 at%Li, respectively.

[0064] In one or more examples, the method includes the step of adding one or more dopants to a mixed composition. The dopants may include one or more of C, S, Si, O, Be, Zn, and Mg. By adding dopants, new compounds can be formed. For example, when using a mixed composition containing gallium, adding magnesium can form LiMgN, thereby synthesizing Mg-doped GaN.

[0065] In one or more examples, at least one element other than lithium and nitrogen comprises at least one flux modifier selected from materials that are in a liquid state under operating conditions. For example, this may include one or more of hydrogen, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, lead, tin, antimony, indium, and bismuth.

[0066] In one or more examples, at least one element other than lithium and nitrogen includes gallium, aluminum, or boron. The method further includes the step of placing the mixed composition in an apparatus. For example, the apparatus is an autoclave. For example, the method includes the step of placing the mixed composition in the upper region of the apparatus for upper seed crystal growth.

[0067] The method further includes the step of supplying nitrogen gas into the apparatus and heating it under high temperature and pressure for a predetermined period of time to obtain a nitrogen-containing material. For example, the apparatus is kept at high temperature for a range of approximately 24 hours to approximately 10,000 hours. For another example, the high temperature is in the range of approximately 1000°C to approximately 1400°C, approximately 1100°C to approximately 1350°C, or approximately 1200°C to approximately 1300°C. For yet another example, the high pressure is in the range of approximately 0.1 MPa to approximately 0.5 MPa.

[0068] As an example, the method includes pressurizing the apparatus with nitrogen gas at room temperature, maintaining a pressure of approximately 0.8 MPa to 1.6 MPa for a predetermined time, and then reducing the pressure to approximately 0.1 MPa to 0.5 MPa before heating. As another example, the method includes adding a catalyst to the mixed composition. As an example, the apparatus is pressurized for a range of approximately 20 minutes to approximately 2 hours.

[0069] As an example, the method includes placing the mixed composition in a crucible 200, for example, on a mesh 220 in the crucible 200, and placing the crucible 200 in an autoclave before heating (see Figure 4). The crucible 200 is placed near a heating device in the apparatus 100 or autoclave to promote crystal growth. The heater 230 may be placed at the bottom or top end of the apparatus 100 or autoclave, and the crystals grow near the heater. Growth from the top has the advantage of allowing for large crystal growth (e.g., Boules with a diameter or width and length exceeding 1 cm, 5 cm, or 10 cm). For example, the method may include using a mechanism to slowly raise the crucible 200 while keeping the crystal surface being grown on the molten / gas interface 210, or lowering the crucible 200 with a drive device to maintain appropriate growth conditions in a manner that closely matches the crystal growth rate.

[0070] To promote the growth of these crystal boules, the growing crystals may be selectively heated by a suitable design of the heating system 230. As an example, the crucible 200 contains one or more of Mo, Nb, Ta, Fe, Re, Ti, BN, Ti, Zr, or Cr. As another example, the crucible 200 contains one or more of Mo, Nb, Ta, Fe, Re, TiC, ZrC, BN, Ti, Zr, ZrN, ZrBN, and Cr3C2.

[0071] As an example, the method includes the step of cooling the apparatus 100 to room temperature to obtain a nitrogen-containing material. As an example, the method further includes the step of separating the nitrogen-containing material from the by-product material.

[0072] As an example, the nitrogen-containing material obtained may contain GaN. As another example, the nitrogen-containing material obtained may contain BN, for example, hexagonal BN. As yet another example, the nitrogen-containing material obtained may contain AlN. As yet another example, the nitrogen-containing material may be a single crystal. The single crystal may have a length and width of at least 1 cm, at least 5 cm, or at least 10 cm. Furthermore, the single crystal may be a Boule crystal having a lattice curvature greater than 100 m and a diameter or width of at least 1 cm.

[0073] Furthermore, nitrogen-containing single crystals with a lattice curvature exceeding 100 m and a diameter or width exceeding 1 cm are also disclosed. As an example, the single crystal material is Boolean. The single crystal material is synthesized via a nitrogen-containing lithium material by the method described herein.

[0074] The nitrogen-containing single crystal may be a GaN Boolean having a length-to-diameter ratio of at least 2:1. The nitrogen-containing GaN single crystal may further have a diameter or width exceeding 10 cm.

[0075] The nitrogen-containing single crystal may be an AlN boolean having a length-to-diameter ratio of at least 2:1. The nitrogen-containing AlN single crystal may further have a diameter or width exceeding 5 cm.

[0076] The nitrogen-containing single crystal is a BN Boole in any of the following forms: hexagonal, wurtzite, rhombohedral, or cubic, and may have a length-to-diameter ratio of at least 0.5:1. The nitrogen-containing BN single crystal may further have a diameter or width exceeding 1 cm.

[0077] Here, the term "diameter," as used above, is not limited to circular crystals. Rather, "diameter" is used to define the size or width of a crystal relative to its length. Therefore, these terms may be used interchangeably to define the dimensions of a crystal in its plane.

[0078] A nitrogen-containing single crystal may have 100% phase purity and be 100% hexagonal, wurtzite, cubic, or rhombohedral. In another example, the single crystal may contain at least 99% of one of the hexagonal, wurtzite, cubic, or rhombohedral phases and about 1% of other phase impurities. In yet another example, the single crystal may contain at least 95% of one of the hexagonal, cubic, or rhombohedral phases and about 5% of one or more other phase impurities. In yet another example, the single crystal may contain at least 90% of one of the hexagonal, wurtzite, cubic, or rhombohedral phases and about 10% of one or more other phase impurities. The nitrogen-containing single crystal may further have a lattice curvature greater than 100 m and a diameter of at least 1 cm, at least 5 cm, or at least 10 cm.

[0079] In one or more examples, a method for synthesizing a nitrogen-containing material includes the step of supplying a molten material into an apparatus 100 and transferring a nitrogen-containing lithium-ion precursor into the molten metal material for a predetermined time to obtain a nitrogen-containing material. As an example, the molten material may include one or more of aluminum, gallium, boron and / or one or more of sodium, potassium, lead, tin, antimony, and indium, which may act as flux modifiers. The use of flux modifiers is useful for changing the properties of the flux and controlling the properties of the growing crystal.

[0080] For example, apparatus 100 is an autoclave and is pressurized with N2 at 1 atmosphere. In another example, apparatus 100 is heated to a temperature in the range of approximately 1000°C to 1500°C, approximately 1100°C to 1350°C, or approximately 1200°C to 1300°C.

[0081] As an example, the molten metal material and the nitrogen-containing lithiumization precursor are supplied in a ratio of approximately 4:1. As an example, the flux in apparatus 100 is nitrogen-deficient (N-deficient) compared to thermodynamically stable / desired conditions. Lowering the N2 pressure in the system reduces the amount of N in the molten metal. The lithiumization precursor may contain binary nitrides or ternary nitrides. As an example, the lithiumization precursor may include Li3N, Li3BN2, Li3GaN2, or Li3AlN2.

[0082] As an example, the nitrogen-containing material obtained may contain GaN. As another example, the nitrogen-containing material obtained may contain BN. As yet another example, the nitrogen-containing material obtained may contain AlN. As yet another example, the nitrogen-containing material may be a single crystal. The single crystal may have a length and width of at least 1 cm, at least 5 cm, or at least 10 cm. Furthermore, the single crystal may be a Boule having a lattice curvature greater than 100 m and a diameter of at least 1 cm.

[0083] In one or more examples, a method for synthesizing a nitrogen-containing material includes the steps of supplying a nitrogen-containing lithium material and an additional material into an apparatus 100 such as an autoclave, and heating the apparatus 100 under N2 at 1 atmosphere to a temperature exceeding the decomposition temperature of the nitrogen-containing lithium material for a predetermined time to obtain the nitrogen-containing material. As an example, the method includes the steps of placing the nitrogen-containing lithium material and the metallic material in the upper region of the apparatus for upper seed crystal growth.

[0084] As an example, the additional material is a reactive material. As another example, the additional material is a dissolving material. One result of using a nitrogen-containing lithium material together with the additional material is the acquisition of ternary or more compounds.

[0085] The lithiumization precursor may include binary nitrides or ternary nitrides. For example, the lithiumization precursor may include Li3N, Li3BN2, Li3GaN2, or Li3AlN2.

[0086] In one or more examples, the mixed composition comprises at least one ternary or more lithium nitride compounds. In another example, the mixed composition comprises one or more of Li3BN2, Li3GaN2, or Li3AlN2. In one or more examples, the mixed composition has a nitrogen solubility or content greater than 1 at%, greater than 5 at%, or greater than 10 at%.

[0087] As an example, the nitrogen-containing material obtained may contain GaN. As another example, the nitrogen-containing material obtained may contain BN. As yet another example, the nitrogen-containing material obtained may contain AlN. As yet another example, the nitrogen-containing material may be a single crystal. The single crystal may have a length and width of at least 1 cm, at least 5 cm, or at least 10 cm. Furthermore, the single crystal may be a Boule having a lattice curvature greater than 100 m and a diameter of at least 1 cm.

[0088] The lithium vapor produced by the method of this disclosure can be controlled by a lower temperature region within the apparatus 100 (autoclave). As an example, lithium vapor is transported to the autoclave. When exposed to high temperature and pressure, the lithium vapor condenses on the walls to form solid Li or Li3N. The Li or Li3N is then removed from the molten material (flux), leaving the desired nitride material. The lithium vapor pressure on the molten material is maintained below equilibrium, thus promoting continuous removal. Thus, the continuous removal of Li leads to the continuous precipitation of nitrogen-containing by-products derived from the decomposition of the lithium precursor material.

[0089] In one or more examples, the methods of the present disclosure may be used to sequentially synthesize ternary or higher alloys by mixing precursors. For example, AlGaN can be synthesized by the methods of the present disclosure by mixing Li3GaN and Li3AlN in molten state. In this example, AlGaN precipitates, and by changing the Ga:Al ratio in molten state and further adjusting the temperature and partial pressure, optimal conditions for synthesizing AlGaN or other ternary alloys can be obtained. Here, AlGaN does not mean a material consisting of aluminum 1, gallium 1, and nitrogen 1, but rather Al x Ga 1-x N is an abbreviation where x takes values ​​from 0 to 1. When x=0, the material is binary GaN, when x=1, it is AlN, and values ​​in between correspond to the Al:Ga atomic ratio in the nitride. The sum of Al and Ga is equal to 1.

[0090] In one or more examples, the methods of the present disclosure may be used to synthesize nitrogen-containing materials comprising AlBN, BGaN, or BAlGaN in any ratio of Al, Ga, and B. In yet another example, the nitrogen-containing material may be Al x Ga 1-x N, Al x B 1-x N, B x Ga 1-x N or B x Al y Ga 1-x-y N is included, where x or y is between 0 and 1 (inclusive).

[0091] The method of this disclosure advantageously provides a solution for growing single-crystal Booleans on a larger scale than currently available, while achieving lattice curvatures exceeding 100 m under conditions of phase purity and diameter exceeding 1 cm. For example, the method of this disclosure can be used for growing single-crystal BN Booleans with diameters and lengths exceeding 1 cm. It can also be used for growing single-crystal AlN Booleans with a diameter of at least 5 cm and a length-to-diameter ratio exceeding 2:1. Furthermore, it can be used for growing single-crystal GaN Booleans with a diameter of at least 10 cm and a length-to-diameter ratio exceeding 2:1.

[0092] The method disclosed herein uniquely utilizes a flux with high nitrogen solubility (25 at%N). Furthermore, by using a lithium-precursor material, high solubility can be obtained for a wide range of elements across the periodic table. This is because lithium nitrides can be formed for almost all elements. The method has the advantage of allowing control of the crystal growth rate through lithium vapor pressure and gas-phase transport. Flux removal after operation can be achieved by decomposition (by burning off the solvent), and does not require complicated methods such as etching to extract the material.

[0093] The method of this disclosure advantageously utilizes a lithium flux (Li3N), which is fully reusable and can be recycled by recrystallization in a separate zone of apparatus 100 (autoclave). The only elements required for recycling are additional nitrogen gas and the elements necessary to form the desired lithium nitride-containing material.

[0094] Another advantage of the method of this disclosure is its adaptability. Since nitrogen does not need to diffuse in the molten material during synthesis, changes in the melting height are not significant. Rather, only the diffusion of lithium away from the interface is required. Crystal growth is limited by temperature rather than by nitrogen arrival (N-arrival), and crystal growth can be controlled by thermal energy and / or lithium / nitrogen pressure.

[0095] Furthermore, the method of this disclosure advantageously avoids the formation of surface crusts. Generally, a gas is introduced into a solution to grow crystals that are molten. The surface layer is exposed to the highest nitrogen concentration, leading to surface crusting, i.e., the formation of solid nitrides at the gas-liquid interface, which blocks the gas flow and prevents nitrogen from easily diffusing into the solid nitride layer. This limits the growth rate and reduces the opportunities that can drive nitride growth.

[0096] Furthermore, an advantage of the method disclosed herein is that the material to be synthesized is already present in the molten state in the form of a precursor. By controlling precursors other than the lithinitride precursor and additional elements in the flux, the polymorphism of the crystal can be controlled. For example, the formation of cubic and hexagonal BN can be controlled.

[0097] Furthermore, the method of this disclosure can be operated in a closed loop. For example, it is not necessary to add or remove additional materials from the system to continue forming the desired material. This also advantageously minimizes the risk of contamination.

[0098] In one or more examples, the methods of the present disclosure utilize Li as a stable liquid nitriding solvent under mild conditions. Controlled removal of Li under enhanced nitrogen activity (by pressurization) results in controlled nitride synthesis. Precursor material (Li x X y N z Compounds are used to achieve nitride growth.

[0099] In accordance with the above disclosure, this method involves reacting element X with lithium to form a ternary nitride, such as Li3XN2, which can then be dissolved in a flux or simply melted (self-fluxed). Subsequently, a slightly high temperature surface (where the crystal is retained) is used. hot At +ΔT), thermal decomposition occurs, forming liquid Li3N and precipitating solid XN. Figure 2 shows T hot The temperature is below the decomposition temperature. In addition to temperature, the growing system can be tuned using two independent parameters: nitrogen and lithium pressure. Nitrogen pressure is used to tune the stability of the nitride (i.e., Li3N and XN), such as GaN, in the molten state. GaN is thermodynamically stabilized from 837°C at 1 atmosphere of N2 to 1040°C at 100 atmospheres of N2. Figure 2 shows a system designed to reach 1000°C at 100 atmospheres, but it should be noted that higher temperatures and pressures are also achievable in the method of this disclosure.

[0100] The stability of Li-containing compounds is controlled by the vapor pressure of Li in the system (see Figure 3). Since lithium melts at 181°C and boils at 1330°C (1 atm), Li vapor can condense on a surface colder than the Li-containing molten material. The vapor pressure of Li3N is mainly composed of Li and N2, and it has been found that the vapor pressure of Li is no more than twice that of pure Li. By intentionally controlling the effective area ratio and temperature between the exposed molten material and the cold wall surface, the Li vapor pressure can be reduced and maintained at a non-equilibrium value. This causes Li to evaporate, further destabilizing the lithium compound in the molten material (e.g., lithium nitride precursor (Li3XN2)). Depending on the kinetics, Li may precipitate as a liquid and drop into a dedicated container, or react with surrounding N2 to form solid Li3N.

[0101] Therefore, the growth of Li3N and XN can occur simultaneously while the flux is consumed. In the case of self-flux melting (where the molten material consists only of LiXN), it is possible to completely utilize all precursor materials and remove only XN after operation without the conventional problems usually associated with removing immersed crystals from the flux that solidifies upon cooling, which is a significant advantage.

[0102] Two distinct approaches can be employed to continuously grow nitrides. These include using a molten material rich in X, where Li3N reacts with the molten X, and using N2 as the nitrogen source to grow Li3N. x X y N z The process involves either forming a structure (requiring an open system and N2 supply) or completely evaporating Li3N using a flux containing the desired amount of Li3XN2 (a closed system suffices). The latter approach is important because it does not require the continuous diffusion or dissolution of N2 into the molten material, which can be a constraint when growing nitrides from molten material.

[0103] Unlike other growth approaches, the approach of this disclosure is significant and unique in that the nitride product is already present in the compound and only needs to be facilitated to release it. This eliminates another challenging aspect of nitride growth, namely the kinetic barrier to reacting element X with nitrogen at a sufficiently low temperature without decomposing the nitride.

[0104] Another important advantage of the method of this disclosure is that the crystals grow thermodynamically in the molten state due to decomposition, rather than by causing supersaturation of nitrogen in the molten state due to excessive N2 pressure. In the latter method, nitrides form on the molten surface and rapidly crust, inhibiting further growth. In this approach, the surface is used to evaporate Li or to react Li with N2 to form liquid Li3N. In either scenario, even at the edges surrounding the liquid-gas-crucible interface, which are typically the most favorable sites for spontaneous and heterogeneous nucleation, conditions are unfavorable for the synthesis of (solid) nitrides on the surface. The absence of surface crusting is a significant advantage and overcomes another potential obstacle in flux-based crystal growth approaches.

[0105] In the closed-system approach, the compound must have the same stoichiometric ratio of Li3N to the growing nitride. Furthermore, this method makes the closed-system approach feasible. Binary and ternary nitrides (BN, AlN, GaN, Al x Ga y N) is thermodynamically stable under the synthesis conditions of this disclosure. The melting points are estimated to be 916°C for Li3BN2 and 1170°C for Li3AlN2, and the decomposition temperatures are estimated to be 838°C, 1000°C, and 900°C for Li3N, Li3AlN2, and Li3GaN2, respectively.

[0106] A strong fundamental understanding of thermodynamics, particularly the relationship and interaction between the stability of the compound and the activities of Li and N in the system, is crucial for the successful growth of these nitrides.

[0107] The method of this disclosure can also be carried out under the following conditions: An autoclave can be used under the conditions shown in the schematic diagram of Figure 2. A cartridge heater or an air / liquid cooled finger can be used to control the lithium vapor pressure. To control the mass flow rate of Li vapor, a two-chamber structure connected by an opening (orifice or mesh) can be used to restrict the overall flow of Li passing through it, allowing for finer control of the evaporation rate and, consequently, the crystal growth rate. By using growth from stoichiometric melting (Li:X:N=3:1:2), the N2 pressure can be dynamically changed during growth in an open system to adjust the stability of the nitrogen-containing compound.

[0108] Growth is controlled by multiple independent parameters, namely PN2, P Li (Depending on the temperature of the cold finger), opening size (mass transfer), T melt , T crystal (T melt It can be controlled by (+ΔT) and molten composition. In situ data such as system pressure, temperature, and gas composition determined by residual gas analysis (RGA) can be collected.

[0109] Analysis of the high-pressure phase diagram of Li3N-BN shows that a single two-phase region of molten Li-BN and solid BN exists just above the melting point of Li3BN2. Under the conditions of this disclosure, continuous removal of Li leads to the formation and growth of BN.

[0110] Autonucleation of hBN is preferred over that of cBN, and growth kinetics generally favor hBN. Purity is also important, and in BN growth using high-pressure, high-temperature anvils, trace amounts of oxygen have been suggested to promote hBN growth. cBN growth on diamond seed crystals (1.4% lattice mismatch) has also been demonstrated under mild conditions (907°C, 1 atm).

[0111] The method for synthesizing ternary nitrides according to this disclosure allows for the synthesis of ternary nitrides from a molten material consisting of two or more lithium ternary nitrides. Specifically, the alloy composition can be controlled by changing the relative concentrations of various elements in the molten material, thereby altering the various activities in the molten material.

[0112] Examples The examples and other embodiments described herein are illustrative and are not intended to limit the entire scope of the compositions and methods of this disclosure. Equivalent changes, modifications, and variations of specific embodiments, materials, compositions, and methods can be made within the scope of this disclosure to produce substantially similar results.

[0113] The following examples provide methods, steps, and materials for growing hBN crystals by the method of the present disclosure. Experiments were conducted using a high-pressure autoclave equipped with a heated metal crucible, in which a hexagonal BN(hBN) crucible was placed. The following materials were placed in the crucible. [Table 1]

[0114] The experiment was conducted under the following conditions: The raw materials for BN and Li3BN2 were weighed in a glove box with low trace oxygen / moisture concentrations under a nitrogen atmosphere. The BN and Li3BN2 were mixed and then loaded into an hBN pyroric crucible. After loading, the hBN crucible was placed inside a metal crucible and then placed inside an autoclave. The autoclave was then sealed and removed from the glove box.

[0115] The system was installed in a heater assembly that selectively heated the zone in which the crucible was placed. To verify the autoclave seal, it was pressurized to 1.2 MPa with 99.9999% high-purity N2 gas at room temperature and held for at least 30 minutes to ensure no pressure drop. The pressure was then reduced to 0.2 MPa. The autoclave was heated to 1200°C at a rate of 4°C / min and held for 34 hours.

[0116] After completion, the power to the heater was cut off and the autoclave was allowed to cool naturally to room temperature. The autoclave was removed from the heater assembly and returned to the glove box for disassembly and sample recovery. The crystalline material in the crucible was separated from the remaining solid material and characterized.

[0117] Sample 1 (hBN crystal) was identified by structural analysis (XRD), optical analysis (Raman, optical microscopy), chemical analysis (EDS), and morphological observation (SEM). Figure 5 shows an overview of the polycrystalline aggregate of grown hBN crystals as captured by SEM. Figure 6 shows a magnified view of the facet region of an hBN flake as captured by SEM. Figure 7 shows the presence of B and N EDS maps in the selected hBN region.

[0118] Figure 8 shows the XRD scan of the hBN sample (top panel) and the hBN reference peak in the powder diffraction file (PDF) (bottom panel). The PDF card used for the XRD scan was 00-045-0893. Figure 9 shows the Raman scattering spectrum of the selected hBN region (shown in inset a). The overall spectrum is shown in a, and the two peaks in the narrower selected region are shown in b. Diamond is an unknown peak (probably an oxide compound), and the asterisk indicates hBN. Focusing on the asterisk in c, the peak is at 1368.8 cm⁻¹. -1 It is located at 1364cm. Raman Peak in HBN is 1364cm. -1 That is the case.

[0119] Figure 10 shows an XRD scan of sample 2 (wurtzite-type GaN material synthesized by the method of this disclosure). For the growth of this material, a crucible was filled with metallic Ga and Li3N (molar ratio 3:2). The crucible was placed in the center of the autoclave and sealed, and the autoclave was placed in a heater system that provided a uniform temperature to the area containing the crucible. The system was pressurized with nitrogen gas to approximately 10 MPa, and then reduced to approximately 4 MPa. The system was heated to approximately 850°C. Subsequently, it was cooled from 850°C to 835°C over approximately 54 hours. During this process, the pressure was maintained at approximately 4 MPa. The system was cooled at the end of the test.

[0120] While the foregoing description and drawings in this specification illustrate embodiments of the present disclosure, it should be understood that various additions, modifications, and substitutions can be made without departing from the spirit and scope of the appended claims and the scope of equivalents. In particular, it will be apparent to those skilled in the art that the invention can be embodied in other forms, structures, arrangements, proportions, sizes, and other elements, materials, and components without departing from its essence or essential features. Furthermore, numerous variations can be made to the methods / processes described herein within the scope of the present disclosure. Those skilled in the art will also understand, without departing from the principles described herein, that embodiments, along with many modifications of structure, arrangement, proportions, sizes, materials, and components, can be used in the practice of the present disclosure and adapted to specific environmental and operating requirements. Accordingly, the embodiments disclosed herein should be considered in all respects to be illustrative and not limiting. The appended claims should be interpreted broadly to include other variations and embodiments that a person skilled in the art may make without departing from the scope of the present disclosure and the scope of equivalents. Furthermore, any combination of all features described herein, in any combination, constitutes part of the present invention.

Claims

1. A method for synthesizing nitrogen-containing materials, A method comprising the steps of: mixing at least one element other than lithium and nitrogen with a nitrogen-containing lithiumization precursor to obtain a mixed composition; placing the mixed composition in an apparatus; supplying nitrogen gas to the apparatus; and heating the apparatus under high temperature and high pressure for a predetermined time to obtain the nitrogen-containing material.

2. The method according to claim 1, wherein the lithiumization precursor comprises a binary nitride.

3. The method according to claim 1, wherein the lithiumization precursor comprises a ternary nitride.

4. A method according to any one of claims 1 to 3, wherein the mixed composition comprises at least one ternary or higher-order lithium nitride compound.

5. In the method according to any one of claims 1 to 4, the lithium precursor is Li ３ N, Li ３ BN ２ Li ３ GaN ２ , or Li ３ AlN ２ A method that includes one or more of the following.

6. In the method according to any one of claims 1 to 5, wherein the mixed composition is Li ３ BN ２ , Li ３ GaN ２ , or Li ３ AlN ２ and the method comprising one or more thereof.

7. A method according to any one of claims 1 to 6, wherein the at least one element other than lithium and nitrogen is gallium, aluminum, or boron.

8. A method according to any one of claims 1 to 7, wherein the element other than lithium and nitrogen comprises an element or material that is dissolved in the flux or in a liquid state under processing conditions, and the element or material may comprise at least one flux modifier selected from hydrogen, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, lead, tin, antimony, indium, and bismuth.

9. A method according to any one of claims 1 to 8, wherein the mixed composition comprises a nitride.

10. A method according to any one of claims 1 to 9, further comprising the step of adding an impurity or dopant to the mixed composition, wherein the impurity or dopant comprises one or more of carbon, sulfur, silicon, germanium, oxygen, beryllium, zinc, or magnesium.

11. A method according to any one of claims 1 to 10, wherein the nitrogen-containing material comprises GaN.

12. A method according to any one of claims 1 to 10, wherein the nitrogen-containing material comprises BN.

13. A method according to any one of claims 1 to 10, wherein the nitrogen-containing material comprises AlN.

14. A method according to any one of claims 1 to 13, wherein the mixed composition has a nitrogen content of more than 1 at%N, more than 5 at%N, or more than 10 at%N.

15. A method according to any one of claims 1 to 14, wherein the nitrogen-containing material comprises AlGaN, AlBN, BGaN, or BAlGaN, and the ratio of Al, Ga, and B is arbitrary.

16. In the method according to any one of claims 1 to 15, the nitrogen-containing material is Al ｘ Ga １－ｘ N, Al ｘ B １－ｘ N, B ｘ Ga １－ｘ N, or B ｘ Al ｙ Ga １－ｘ－ｙ A method that includes N, where x or y is between 0 and 1 (inclusive).

17. A method according to any one of claims 1 to 16, wherein the nitrogen-containing material comprises a controlled amount of dopant or impurity.

18. A method according to any one of claims 1 to 17, wherein the nitrogen-containing material is a single crystal.

19. A method according to any one of claims 1 to 18, wherein the nitrogen-containing material is a single crystal boule with a diameter of at least 1 cm, at least 5 cm, or at least 10 cm.

20. A method according to any one of claims 1 to 19, wherein the apparatus is an autoclave.

21. A method according to any one of claims 1 to 20, wherein the high temperature is in the range of about 800°C to about 1600°C.

22. A method according to any one of claims 1 to 21, wherein the high pressure is in the range of about 0.1 MPa to about 100 MPa.

23. A method according to any one of claims 1 to 22, further comprising the steps of: placing the mixed composition in a crucible; and placing the crucible in an autoclave before heating.

24. The method according to claim 23, wherein the crucible is positioned near the heating device within the apparatus.

25. The method according to claim 23 or 24, wherein the crucible contains one or more of B, C, N, O, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, or Re.

26. A method according to any one of claims 1 to 25, further comprising the steps of pressurizing the apparatus with nitrogen gas to a pressure in the range of 0.1 MPa to 100 MPa at room temperature for a predetermined time, and reducing the pressure to a pressure in the range of 0.1 MPa to 10 MPa before or immediately after heating.

27. The method according to claim 26, wherein the apparatus is pressurized for a predetermined time from about 20 minutes to about 24 hours.

28. A method according to any one of claims 1 to 27, further comprising the step of adding at least one flux modifier to the mixed composition.

29. A method according to any one of claims 1 to 28, further comprising the step of separating the nitrogen-containing material from the by-product material.

30. A method for synthesizing a nitrogen-containing material, comprising the steps of: supplying a molten material into an apparatus; and passing a nitrogen-containing lithium-ion precursor through the molten material for a predetermined time to obtain the nitrogen-containing material.

31. In the method according to claim 30, the apparatus is N2 at 1 atmosphere ２ A method of applying pressure from below.

32. A method according to claim 30 or 31, wherein the molten material comprises one or more of aluminum, gallium, boron, sodium, potassium, cesium, lead, tin, antimony, and indium.

33. A method according to any one of claims 30 to 32, wherein the apparatus is heated to a temperature in the range of about 800°C to about 1600°C.

34. A method according to any one of claims 30 to 33, wherein the lithiumization precursor comprises a binary nitride.

35. A method according to any one of claims 30 to 33, wherein the lithiumization precursor comprises one or more ternnitrides.

36. In the method according to any one of claims 30 to 35, the lithium precursor is Li ３ N, Li ３ BN ２ Li ３ GaN ２ or Li ３ AlN ２ A method that includes one or more of the following.

37. A method according to any one of claims 30 to 36, wherein the nitrogen-containing material comprises GaN.

38. A method according to any one of claims 30 to 36, wherein the nitrogen-containing material comprises BN.

39. A method according to any one of claims 30 to 36, wherein the nitrogen-containing material comprises AlN.

40. In the method according to any one of claims 30 to 39, the nitrogen-containing material is Al ｘ Ga １－ｘ NI, Al ｘ B １－ｘ N, B ｘ Ga １－ｘ N, or B ｘ Al ｙ Ga １－ｘ－ｙ A method that includes N, where x or y is between 0 and 1 (inclusive).

41. A method according to any one of claims 30 to 40, wherein the nitrogen-containing material comprises a controlled amount of dopant or impurity.

42. A method according to any one of claims 30 to 41, wherein the nitrogen-containing material is a single crystal.

43. A method according to any one of claims 30 to 42, wherein the nitrogen-containing material is a single crystal boule with a diameter of at least 1 cm, at least 5 cm, or at least 10 cm.

44. A method according to any one of claims 30 to 43, wherein the apparatus is an autoclave.

45. A method for synthesizing nitrogen-containing materials, comprising the steps of supplying nitrogen-containing lithium material and non-lithium material into an apparatus, and providing the apparatus with at least 1 atmosphere of N ２ A method comprising the step of heating the nitrogen-containing lithium material to a temperature exceeding the decomposition temperature for a predetermined time to obtain the nitrogen-containing material.

46. The method according to claim 45, wherein the lithiumization precursor comprises a binary nitride.

47. The method according to claim 45, wherein the lithiumization precursor comprises a ternary or higher nitride.

48. The method according to any one of claims 45 to 47, wherein the lithium precursor is Li ３ N, Li ３ BN ２ Li ３ GaN ２ , or Li ３ AlN ２ A method that includes this.

49. In the method according to any one of claims 45 to 48, the nitrogen-containing material is Al ｘ Ga １－ｘ NI, Al ｘ B １－ｘ N, B ｘ Ga １－ｘ N, or B ｘ Al ｙ Ga １－ｘ－ｙ A method that includes N, where x or y is between 0 and 1 (inclusive).

50. A method according to any one of claims 45 to 49, wherein the nitrogen-containing material comprises a controlled amount of dopant or impurity.

51. A method according to any one of claims 45 to 50, wherein the non-lithiumized material comprises a dissolved element.

52. A method according to any one of claims 45 to 51, wherein the non-lithium material comprises a reactive material.

53. A method according to any one of claims 45 to 52, wherein the nitrogen-containing material comprises GaN.

54. A method according to any one of claims 45 to 52, wherein the nitrogen-containing material comprises BN.

55. A method according to any one of claims 45 to 52, wherein the nitrogen-containing material comprises AlN.

56. A method according to any one of claims 45 to 55, wherein the nitrogen-containing material is a single crystal.

57. A method according to any one of claims 45 to 56, wherein the nitrogen-containing material is a single crystal boule with a diameter of at least 1 cm, at least 5 cm, or at least 10 cm.

58. A method according to any one of claims 45 to 57, wherein the apparatus is an autoclave.

59. A nitrogen-containing single crystal comprising GaN, having a diameter of at least 50 mm, and having a length-to-diameter ratio of at least 1:

1.

60. A single crystal according to claim 59, having a lattice curvature of more than 100 m and a diameter of more than 1 cm.

61. A single crystal according to claim 59 or 60, wherein the single crystal material is Boolean.

62. A single crystal according to any one of claims 59 to 61, wherein the single crystal is synthesized via a nitrogen-containing lithium material.

62. A single crystal according to any one of claims 59 to 62, comprising a controlled amount of dopant or impurity.

63. A nitrogen-containing single crystal comprising AlN, having a diameter of at least 50 mm, and having a length-to-diameter ratio of at least 2:

1.

64. A single crystal according to claim 63, having a lattice curvature of more than 100 m and a diameter of more than 1 cm.

65. A single crystal according to claim 63 or 64, wherein the single crystal material is Boolean.

66. A single crystal according to any one of claims 63 to 65, wherein the single crystal is synthesized via a nitrogen-containing lithium material.

67. A single crystal according to any one of claims 63 to 66, comprising a controlled amount of dopant or impurity.

68. A nitrogen-containing single crystal comprising BN, having a diameter of at least 10 mm, and having a length-to-diameter ratio of at least 1:

2.

69. A single crystal according to claim 68, having a lattice curvature of more than 100 m and a diameter of more than 1 cm.

70. A single crystal according to claim 68 or 69, wherein the single crystal material is Boolean.

71. A single crystal according to any one of claims 68 to 70, wherein the single crystal is synthesized via a nitrogen-containing lithium material.

72. A single crystal according to any one of claims 68 to 71, comprising a controlled amount of dopant or impurity.

73. A single crystal according to any one of claims 59 to 72, wherein the single crystal has at least 100%, at least 99%, or at least 95% of a hexagonal, wurtzite, cubic, or rhombohedral phase.

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