KR101830524B1 - Two-dimensional large-area metal chalcogenide single crystals and method for manufactruing the same - Google Patents

Abstract

The present invention relates to a two-dimensional large-area metal chalcogenide single crystal, and a manufacturing method thereof. The two-dimensional large-area metal chalcogenide single crystal comprises: at least one of metal elements of group 3 to group 14 in the periodic table; and at least one chalcogen element of group 16 in the periodic table, and has the diameter or the length of 15 mm or thicker. The present invention can provide a large-area and high-quality two-dimensional large-area metal chalcogenide single crystal.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-area two-dimensional metal-chalcogenide single crystal and a method for manufacturing the same. 2. Description of the Related Art TWO-DIMENSIONAL LARGE-AREA METAL CHALCOGENIDE SINGLE CRYSTALS AND METHOD FOR MANUFACTRUING THE SAME

The present invention relates to a large-area bulk two-dimensional metal-chalcogen compound single crystal and a manufacturing method thereof.

Bulk transition metal-chalcogen compounds are two-dimensional materials that have large electrical, magnetic, and optical anisotropy and are separable as graphene. Especially, they have a bandgap, which is the next generation core material to replace silicon-based semiconductors. It is acknowledged.

Bulk transition metal-chalcogen compounds are produced in two-dimensional materials through artificial synthesis because they are almost nonexistent in natural systems except molybdenum disulphide (MoS ₂ ). Bulk transition metal chalcogen compounds are generally produced by two-stage chemical vapor transport Are manufactured by the method.

In the conventional chemical vapor transport method, the two-zone temperature region in the horizontal direction is divided into a source part and a growth part, and a temperature gradient is applied to the single part to produce a single crystal lump material. , And the two-dimensional chemical materials produced by the two-stage chemical vapor transportation method are very limited in size within a few millimeters, and the supply cost is so high that they are limited to the use as electronic parts and semiconductor materials.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a large-area two-dimensional metal-chalcogenide single crystal having high bulk bulk- .

The present invention also provides a method for producing a large-area two-dimensional metal-chalcogen compound single crystal capable of forming a large-area single crystal by constituting a three-stage temperature region in a chemical vapor transportation method and reducing the supply cost of a material .

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to one aspect of the present invention, there is provided a semiconductor device comprising: at least one metal element selected from Group 3 to Group 14 of the periodic table; And at least one chalcogen element of group 16 of the periodic table; And a large-area two-dimensional metal-chalcogen compound single crystal having a diameter or a length of 15 mm or more.

According to an embodiment of the present invention, the metal element may be at least one selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, (Ni), Cu, Zn, Ga, Ge, Zr, Nb, Mo, Tc, (Ru), Rh, Rh, Cd, In, Sn, Sb, Ta, W, Wherein the chalcogen element is at least one element selected from the group consisting of sulfur (S), selenium (Se) and selenium (Se) and at least one element selected from the group consisting of mercury (Hg), thallium (Tl), lead (Pb), and bismuth Tellurium (Te), and the like.

According to an embodiment of the present invention, the metal-chalcogen compound single crystal may be selected from the group consisting of MX ₂ or MX (wherein M is a transition metal element of Group 3 to 12 of the periodic table and X is a chalcogen element of Group 16 of the periodic table) , Which may be a bivalent transition metal-chalcogen compound.

According to an embodiment of the present invention, the metal-chalcogen compound single crystal may be represented by M _a X ' _b X _c (wherein M is a transition metal element of Group 3 through Group 12 of the periodic table, X' and X are mutually different , A chalcogen element of Group 16 of the periodic table, and a, b, and c are rational numbers of 50 or less).

According to an embodiment of the present invention, the metal-chalcogen compound single crystal may be represented by M _a M ' _b X _c (wherein M and M' are different from each other and are a transition metal element of Group 3 through Group 12 of the periodic table and X Is a chalcogen element of Group 16 of the periodic table, and a, b, and c are rational numbers of 50 or less).

According to an embodiment of the present invention, the metal-chalcogen compound single crystal is represented by M _a M ' _b X _c X' _d , wherein M and M 'are different from each other, and the transition metal element of Groups 3 to 12 of the periodic table , X and X 'are different from each other, and are a chalcogen element of Group 16 of the periodic table, and a, b, c and d are rational numbers of 50 or less).

According to one embodiment of the present invention, the metal-chalcogenide single _{crystal, FeTe, NiTe 2, CoTe 2} , MoS 2, MoTe 2, MoSe 2, TiSe 2, TiTe 2, WTe 2, WSe 2, MoS 2 ( _{1-x) Se 2x, MoSe} 2 (1-x) Te 2x, WSe 2 (1-x) Te 2x, WS 2 (1-x) Te 2x, TiSe 2 (1-x) Te 2x, _{WTiSe 2, MoWTe 2, MoNbSe 2} , TiTaSe 2, MoWSe 2 (1-x) Te 2x, WTiS 2 (1-x) Se 2x, NbS 2 (1-x) Se 2x, NbSe 2 (1-x) Te _2x, TiS comprise a _{2 (1-x) Se 2x} , ReS 2 (1-x) Se 2x, and _{ReSe 2 (1-x) Te} 2x 1 or more from the group consisting of (wherein, x is a rational number) .

According to another aspect of the present invention,

Placing a quartz tube sealed with the sample raw material at the center of the crystal growth furnace; Producing a single crystal; And cooling the crystal growth furnace; Wherein the sample material is at least one of metal elements of group 3 to group 14 of the periodic table; And at least one chalcogen element of group 16 of the periodic table; Wherein the step of producing the single crystal is to produce a single crystal using a three-stage temperature region formed in the crystal growth furnace.

According to an embodiment of the present invention, the three-stage temperature region is divided into a raw material region; A crystal growth region; And an activation region; , And the crystal growth region can be adjusted to a temperature different from the raw material region and the activation region.

According to an embodiment of the present invention, the raw material region and the crystal growth region may have a temperature difference of 100 ° C to 200 ° C.

According to one embodiment of the present invention, the activation region may be controlled to a temperature which is the same as or different from that of the raw material region.

According to an embodiment of the present invention, the activation region may have a temperature difference of 100 DEG C or less from the raw material region.

According to an embodiment of the present invention, the step of preparing the single crystal may include the steps of preheating the raw material region, the crystal growth region and the activation region; Forming a temperature gradient region by lowering the temperature of the raw material region; And raising the temperature of the raw material region and lowering the temperature of the crystal growth region to grow crystals; . ≪ / RTI >

According to one embodiment of the present invention, the preheating step can maintain the temperature for 40 to 50 hours after raising the temperature to 800 to 1200 DEG C at a rate of 15 DEG C / h to 25 DEG C / h .

According to an embodiment of the present invention, the step of forming the temperature gradient region may include lowering the raw material region to a temperature of 600 ° C to 1000 ° C at a rate of 3 ° C / h to 5 ° C / h, The temperature of the region may be lower than the temperature of the crystal growth region.

According to one embodiment of the present invention, the step of growing the crystal includes heating the raw material region to a temperature of 800 ° C to 1200 ° C at a rate of 3 ° C / h to 5 ° C / h, The temperature of the raw material region is lowered to a temperature of 600 ° C to 1000 ° C at a rate of 3 ° C / h to 5 ° C / h, and the temperature is maintained for 15 days to 20 days after the temperature rise and fall, Region, and the activation region may have the same temperature condition as the raw material region.

According to one embodiment of the present invention, the raw material of the sample may be a polycrystalline or single crystal of metal and chalcogen elements formed by crystal growth at a temperature of 1000 ° C to 1200 ° C using Bridgman's method.

According to one embodiment of the present invention, the sample material is selected from the group consisting of a halogen element, a halogenated-metal and a halogenated-chalcogen; One or more transport media.

According to an embodiment of the present invention, the cooling step includes a first cooling step of lowering the crystal growth furnace from 350 DEG C to 450 DEG C at a rate of 2 DEG C / h to 4 DEG C / h; And a second cooling step of lowering the temperature to a room temperature at a rate of 5 ° C / h to 10 ° C / h after the first cooling step; . ≪ / RTI >

According to an embodiment of the present invention, after the cooling step, the temperature of the crystal growth region is raised by 150 to 250 DEG C higher than that of the raw material region and maintained at the above temperature for 5 to 10 hours Removing unreacted raw materials and impurities in the crystal growth region; As shown in FIG.

INDUSTRIAL APPLICABILITY The present invention can provide a large-sized, high-quality bulk two-dimensional metal-chalcogen compound single crystal. The two-dimensional metal-chalcogen compound single crystal according to the present invention can be produced by a conventional chemical vapor transport method or has a size more than twice as large as that of commercially available and reported metal-chalcogen compound single crystals, It can be used as a component material of an electronic device that can be used.

The present invention can provide a method of manufacturing a large-area two-dimensional metal-chalcogen compound single crystal which overcomes the size limitation of a single crystal according to a two-stage chemical vapor transport method and produces a large-area high-quality bulk single crystal. The manufacturing method according to the present invention can exclusively promote side growth only during crystal growth, thereby forming a large-area single crystal and reducing the manufacturing cost of the large-area bulk single crystal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary flow chart of a method for manufacturing a large-area two-dimensional metal-chalcogenide single crystal of the present invention, according to one embodiment of the present invention.
Figure 2a illustrates, by way of example, a cross section of a vertical bridge only apparatus, in accordance with an embodiment of the present invention.
FIG. 2B is an illustration of temperature control in the step of preparing the sample raw material of the present invention, according to an embodiment of the present invention.
3 schematically shows an example of a three-stage temperature region formed in a crystal growth furnace in the step of producing a single crystal of the present invention, according to an embodiment of the present invention.
4 shows the size of a bulk WSe ₂ single crystal produced according to Example 1 of the present invention.
5 shows the results of XRD and component analysis of a bulk WSe ₂ single crystal produced according to Example 1 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, terms used in this specification are terms used to appropriately express the preferred embodiments of the present invention, which may vary depending on the user, the intention of the operator, or the practice of the field to which the present invention belongs. In this specification, the definitions of these terms shall be based on the contents throughout this specification.

The present invention relates to a two-dimensional metal-chalcogen compound single crystal. According to one embodiment of the present invention, the two-dimensional metal-chalcogen compound single crystal is twice as large as a conventional two- High-quality bulk two-dimensional metal-chalcogen compound single crystal having a size of 1 to 10 times larger than that of the bulk single-dimensional metal-chalcogen compound single crystal.

In one example of the present invention, a two-dimensional metal-chalcogen compound single crystal has a crystal grain size of 10 mm or more; 15 mm or more; Or 20 nm or more; Or 15 to 100 mm in diameter or length.

In one embodiment of the present invention, the two-dimensional metal-chalcogenide single crystal is at least one of the metal elements of Group 3 to Group 14 of the periodic table; And at least one chalcogen element of group 16 of the periodic table; A three-element system, or a quaternary system, which is a binary system, a ternary system, or a quaternary system including a transition metal, Transition metal-chalcogen compound single crystal.

For example, the metal element may be at least one selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, (Cu), Zn, Ga, Ge, Zr, Nb, Molybdenum, Tc, Ru, (Rh), Cd, In, Sn, Sb, Ta, W, Re, Ir, Hg ), Thallium (Tl), lead (Pb), and bismuth (Bi).

For example, the chalcogen element may include at least one element selected from the group consisting of sulfur (S), selenium (Se), and tellurium (Te).

For example, the two-dimensional metal-chalcogen compound single crystal may be a binary metal-chalcogen compound represented by MX ₂ or MX. M is a metal element selected from Group 3 to Group 14 of the periodic table, preferably a transition metal of Group 3 to Group 12, and X may be a chalcogen element selected from Group 16 of the periodic table.

For example, the two-dimensional metal-chalcogen compound single crystal may be a ternary metal-chalcogen compound represented by M _a X ' _b X _c . The M is a metal element selected from Group 3 to Group 14 of the periodic table, preferably a transition metal of Groups 3 to 12. X 'and X are different from each other and are a chalcogen element of Group 16 of the periodic table, and a, b, and c are rational numbers of 50 or less, and can be appropriately selected according to the oxidation number and / or stoichiometry of the metal in the compound. have.

For example, the two-dimensional metal-chalcogen compound single crystal may be a ternary metal-chalcogen compound represented by M _a M ' _b X _c . The M and M 'are different from each other and are a metal element selected from Group 3 to Group 14 of the periodic table, preferably a transition metal element of Groups 3 to 12. X is a chalcogen element selected from Group 16 of the periodic table, and a, b, and c are free ratios of 50 or less, and can be appropriately selected according to the oxidation number and / or stoichiometry of the metal in the compound.

For example, the two-dimensional metal-chalcogen compound single crystal may be a quaternary metal-chalcogen compound represented by M _a M ' _b X _c X' _d . The M and M 'are different from each other and are a metal element selected from Group 3 to Group 14 of the periodic table, preferably a transition metal element of Groups 3 to 12. X ' and X are different from each other and are chalcogen elements of Group 16 of the periodic table, and a, b, c and d are rational numbers of 50 or less and are appropriately selected according to the oxidation number and / or stoichiometry of the metal in the compound .

According to one embodiment of the invention, the two-dimensional metal-chalcogenide single crystal, FeTe, NiTe _2, CoTe _2, MoS _2, MoTe _2, MoSe _2, TiSe _2, TiTe _2, WTe _2, WSe _2, MoS _{2 (1-x) Se 2x} , MoSe 2 (1-x) Te 2x, WSe 2 (1-x) Te 2x, WS 2 (1-x) Te 2x, TiSe 2 (1-x) Te 2x, _{WTiSe 2, MoWTe 2, MoNbSe 2} , TiTaSe 2, MoWSe 2 (1-x) Te 2x, WTiS 2 (1-x) Se 2x, NbS 2 (1-x) Se 2x, NbSe 2 (1-x) Te _2x, TiS comprise a _{2 (1-x) Se 2x} , ReS 2 (1-x) Se 2x, and _{ReSe 2 (1-x) Te} 2x 1 or more from the group consisting of (wherein, X is a rational number) .

The present invention relates to a method for producing a two-dimensional metal-chalcogenide single crystal, and in the method for producing a single crystal using a chemical vapor transport method, a three-step temperature region is formed in a growth furnace To solve the size limitation in single crystal growth, thereby providing a large-area high-quality two-dimensional metal-chalcogen compound single crystal.

According to one embodiment of the present invention, the manufacturing method will be described with reference to Fig. 1, wherein Fig. 1 is a cross-sectional view of a large-area two-dimensional metal-chalcogen compound single crystal according to an embodiment of the present invention (S1) of preparing a sample raw material; Placing the sample material in a crystal growth furnace (S2); Producing a single crystal (S3); And cooling (S4); . ≪ / RTI >

In one embodiment of the present invention, the step (S1) of preparing the sample raw material comprises preparing a sample raw material consisting of single crystal and polycrystal including reactive elements for a desired single crystal, grinding the same and sealing it in an ampule .

For example, the ampoule may be a quartz tube and the purity of the sample material may be greater than or equal to 4N (99.99%).

For example, the raw material of the sample may be a single crystal or a polycrystal including raw materials and may be a polycrystalline or single crystal of a metal and a chalcogen element formed by crystal growth using Bridgman's method .

For example, referring to FIG. 2A, FIG. 2A illustrates an exemplary cross-section of a vertical bridge only device in accordance with an embodiment of the present invention. In FIG. 2A, a siliconit is used as a heating element, Only the vertical bridge where the highest temperature is maintained at about 1600 ° C is injected into the electric furnace with the raw material sealed in the ampoule. Next, as shown in FIG. 2B, the temperature of the raw material is liquefied by maintaining the temperature at a temperature of 20O < 0 > C / h from 550 to 650 DEG C for 20 to 25 hours, A growth temperature can be formed, and the temperature can be maintained to start crystal growth. As described above, since the temperature is raised in two steps, the reaction tube is prevented from exploding, and the crystal growth can be started by completely mixing the raw materials. The temperature and the temperature holding time of the highest temperature part can be appropriately selected depending on the kind of the raw material and the bonding form of the compound, for example, a binary system, a ternary compound or the like. For example, the crystal growth can be carried out by raising the temperature to 1000 占 폚 to 1150 占 폚 at a heating rate of 10 占 폚 / h, and maintaining the temperature for 5 days to 6 days. After the crystal growth, it is cooled down to a constant temperature at a descending rate of 5 DEG C / h and then naturally cooled. This is because even if the crystal growth of the raw material is terminated, the supercooling due to cooling is induced when the crystal in the high temperature state is rapidly cooled, and as a result, the polycrystallization due to the additional nucleation is prevented from progressing, The quality of the single crystal can be prevented from deteriorating. Next, the synthesized sample raw material is pulverized into fine powder and sealed in an ampoule.

For example, the sample material may further comprise a transport medium, the transport medium being selected from the group consisting of a halogenated metal; Halogenated-chalcogen; And halogen; (I ₂ ), chlorine (Cl ₂ ), bromine (Br ₂ ), halogenated-metal (Periodic Table 3 to 14), halogenated-chalcogen Group 16 of the Periodic Table of Elements), and combinations thereof.

For example, in the case of the halogen, it is added at a rate of 5 to 10 mg / cm ³ per ampoule unit, and the halogenated-metal and halogenated-chalcogen materials can be weighed appropriately by mole ratio.

According to an embodiment of the present invention, the step (S2) of placing the sample material in the crystal growth furnace is a step of positioning the quartz tube sealed with the sample material at the center of the crystal growth furnace, Meteorological transport can be a horizontal electric furnace. The crystal growth furnace is composed of a raw material region, a crystal growth region, and an activation region, and will be described in more detail in a step S3 of manufacturing the following single crystal.

According to an embodiment of the present invention, the step (S3) of producing a single crystal is a step of growing a two-dimensional metal-chalcogen compound single crystal in a crystal filamentary furnace, wherein the three- Single crystal is grown by chemical vapor transport method. These three-stage temperature regions are formed independently of each other, and efficient temperature transfer and control are possible. In addition, the three-stage temperature region can control multiple nucleation by arbitrarily adjusting the supersaturation during crystal growth, and exclusively promote lateral growth, thereby obtaining a large-sized high-quality bulk single crystal Can be prepared.

For example, referring to FIG. 3, FIG. 3 illustrates a three-step temperature region formed in a crystal growth furnace in the step of manufacturing a single crystal according to the present invention. In FIG. 3, Sequentially in the direction of the depth of the raw material region T1; A crystal growth region T2; And an activation region (T3); . ≪ / RTI > The three-stage temperature region can be defined according to the position and / or the temperature distribution of the raw material of the sample, and the three-stage temperature region can be adjusted to the same or different temperature according to each step of the production method.

For example, the raw material region T1 is defined as a region in which the sample material is located in the crystal growth furnace and its surroundings.

For example, the crystal growth region T2 is a region where raw materials are combined and a single crystal is grown, and the crystal growth region T2 is the same as the raw material region T1 and the activation region T3 Or may be adjusted to a different temperature. For example, the crystal growth region T2 may have a temperature difference of 100 占 폚 to 200 占 폚 with the raw material region T1, and preferably has a lower temperature of 100 占 폚 to 200 占 폚 than the raw material region T1 Crystalline growth can be achieved at temperature. When the temperature difference is less than 100 占 폚, the temperature of the crystal growth region T2 is too close to the temperature of the raw material region T1, so that nuclei are not generated well and it is difficult to obtain a desired single crystal. The polycrystalline shape in which a small size single crystal is randomly bonded due to active nucleation can be generated, for example, when the temperature is maintained at a temperature lower than 200 DEG C as compared with the raw material region T1, I do not.

For example, the activation region T3 is a buffer region that regulates the thermal gradient between the raw material region T1 and the crystal growth region T2 and maintains homeostasis during crystal growth. For example, when the temperature gradient between the raw material region T1 and the crystal growth region T2 is large, it is difficult to maintain the homeostasis during the crystal growth time. However, in the activation region T3, The temperature gradient of the growth region T2 is lowered to maintain the homogeneity and the growth of a large-area bulk single crystal of good quality becomes possible. The activation region T3 may be controlled to a temperature equal to or different from that of the raw material region T1 depending on each process, It may have a temperature difference.

In one embodiment of the present invention, the step (S3) of producing a single crystal includes a preheating step (S3a); Forming a temperature gradient region (S3b); And growing a crystal (S3c); . ≪ / RTI >

For example, the preheating step S3a is a step of preheating the raw material region T1, the crystal growth region T2 and the activation region T3, and after preheating to a specific temperature, the reaction element Can be kept sufficiently responsive. The raw material region T1, the crystal growth region T2 and the activation region T3 can be preheated to the same temperature, for example, 15 ° C / h to 25 ° C / h; 20 [deg.] C / h to 22 [deg.] C / h; Or 800 ° C to 1200 ° C at a rate of 20 ° C / h; Or from 40 to 50 hours after the temperature is raised to a temperature of 1000 to 1100 占 폚; 45 hours to 50 hours; Alternatively, the temperature can be maintained for 48 hours.

For example, the step S3b of forming the temperature gradient region is a step of lowering the temperature of the raw material region T1 to form a temperature gradient region. For example, the raw material region T1 is heated at a rate of 3 DEG C / h to 5 DEG C / h; Or at a rate of 4 캜 / h to a temperature of 600 캜 to 1000 캜. The crystal growth region T2 and the activation region T3 are maintained at the regulated temperature in the preheating step S3a in the step S3b of forming the temperature gradient region and the crystal growth region T2 is maintained in the raw material region T1 ). ≪ / RTI > This makes it possible to transfer impurities or the like present in the high temperature crystal growth region T2 of the ampule in which the sample raw material is sealed to the low temperature raw material region T1 to clean the crystal growth region T2.

For example, the step of growing crystals S3c is a step of raising the temperature of the raw material region T1 and lowering the temperature of the crystal growth region T2 to grow crystals. The raw material region T1 has a temperature of 3 DEG C / h to 5 DEG C / h; Or 4 ° C / h to 800 ° C to 1200 ° C, and the crystal growth region T2 is heated at a rate of 3 ° C / h to 5 ° C / h; Or at a rate of 4 DEG C / h to a temperature of 600 DEG C to 1000 DEG C, and from 15 days to 20 days after the temperature rise and fall; Or may be maintained at the regulated temperature for 15 days. The raw material region T1 is controlled to a temperature higher than the crystal growth region T2 and the crystal growth region T2 is controlled at a temperature lower than the temperature of the raw material region T1 in the step S3c of growing the crystal, The growth temperature is formed and maintained. The activation region T3 is controlled to the same temperature condition as the source material region T1 and prevents the regulated temperature of the crystal growth region T2 from being lowered in the step S3c of growing the crystal, Supersaturation inhibits nucleation and promotes growth in the lateral direction necessary for large-scale growth.

In one embodiment of the present invention, the cooling step S4 is a step of cooling the crystal growth furnace after the step S3c of growing the crystal. For example, from 350 ° C to 450 ° C at a rate of 2 ° C / h to 4 ° C / h; And a second cooling step of rapidly lowering the temperature to a normal temperature at a rate of 5 ° C / h to 10 ° C / h after the first cooling step; . ≪ / RTI > A sufficient amount of crystallization is induced in the first cooling step by slow cooling to induce sufficient crystallization and the amount of the dissociated elements during cooling is quenched to a maximum temperature in the second cooling step to obtain a single crystal having the same composition ratio or close to the composition ratio .

The method may further include a step (S5) of removing unreacted raw materials and impurities after the step (S4) of cooling the crystal growth furnace as an example of the present invention. For example, Is heated to a temperature higher by 150 to 250 占 폚 than the raw material region T1 and maintained at the above temperature for 5 to 10 hours to be adsorbed on the surface of the crystal growth region T2 in the crystal growth region T2 Transport media, impurities, unreacted raw materials, and the like can be removed.

The present invention is not limited thereto but may be embodied in other specific forms without departing from the spirit or scope of the present invention as set forth in the following claims, The present invention can be variously modified and changed.

Manufacturing example  One

(1) WSe₂ Single crystal manufacturing

The ampoule was cone-shaped with an oxygen-propane flame so that the end of a quartz tube with an inner diameter of 9 mm, a thickness of 1 mm and a length of 12 cm could be easily formed into a seed. This was immersed in a washing solution (H ₂ O: K ₂ Cr ₂ O ₇ : H ₂ SO ₄ ) for 24 hours, washed, and then washed several times in the order of distilled water, acetone, methanol and distilled water. In order to prevent the W and Se materials from reacting with the inner wall of the quartz tube in the molten state, the inside of the casting tube was completely opaque carbon coated at about 1300 ° C. higher than the growth temperature. Since the raw material is easily oxidized in air, the oxide film is removed with 5% HNO ₃ and 5% HCl, and W (3N) and Se (5N) are put into a carbon coated quartz tube. Lt; ^-6 > torr. Next, a sealed quartz tube for growth was placed in an alumina tube, and a quartz ring was inserted between the alumina tube and the ampoule to prevent the ampule from tilting. Then, the tube was manually lowered and conical Was mounted so that the end portion of the tube was positioned. The temperature of the electric furnace was controlled by a microcomputer temperature control program, and crystal growth was started. When the temperature of the raw material containing selenium (Se) is controlled by the temperature control shown in FIG. 2 and the temperature of the raw material including the selenium (Se) is increased due to the high vapor pressure, the reaction tube may explode. Therefore, After heating, the raw material was liquefied by keeping it for 24 hours. Next, the temperature was raised from 1000 ° C to 1150 ° C at a rate of 10 ° C / h to prevent the reaction tube from exploding, and the crystal growth was started so that the raw materials were completely mixed. This temperature is maintained for 7 days. Finally, after the crystal growth was completed, the mixture was gradually cooled to a constant temperature at a rate of 5 ° C / h and then cooled naturally.

Example  One

The raw material obtained in Preparation Example 1 was pulverized into fine powder, and then treated with iodine (I ₂ ) as a transport medium to a processed ampoule having an inner diameter of 10 mm, a thickness of 2 mm and a length of 10 cm, 6g to the total mass of the degree to be weighed in the ratio 2 × 10 ^- sealed in a vacuum of about ⁶ torr. The sealed ampoules were mounted in a three-stage chemical vapor transport horizontal electric furnace and then elevated to a temperature of 1200 DEG C at a rate of 20 DEG C / h and held for 48 hours. Next, the temperature of the raw material region was lowered to 1000 캜 at a rate of 4 캜 / h and maintained for 48 hours. Then, the temperature of the raw material region was raised to 1200 占 폚 at a rate of 4 占 폚 / h, and the crystal growth region was crystallized while being maintained at a temperature of 4 占 폚 / h to 1000 占 폚 for 15 days. At this time, the activation region is at the same temperature as the raw material region. After the crystal growth was completed, the electric furnace was cooled to 400 DEG C at a rate of 2 DEG C / h, and then rapidly cooled to room temperature. After reaching the room temperature, the temperature of the crystal growth region was raised to 200 ° C., maintained for 6 hours, and then naturally cooled. The quartz tube was separated to obtain WSe ₂ single crystals. The WSe ₂ single crystal was subjected to structural analysis through image, XRD and EDS, and shown in FIGS. 4 and 5.

4 and 5, the WSe ₂ produced in Example 1 has a length of 35 mm, which is a commercially available product (2D semiconductor (3 x 3 mm ² ), hq graphene ( ⁵ x ⁵ mm ² ), SPI yarn (3 x 3 mm ² ), which is much larger than WSe ₂ ). In the structural analysis, WSe ₂ single crystals were confirmed in the XRD pattern, and the single crystal component ratio was confirmed in the EDS component analysis.

The present invention can be applied to a crystal growth process in a three-step temperature region, which can provide a large-sized bulk single crystal that is much larger than conventional metal-chalcogen compound single crystals, and can provide a high-quality single crystal at an economical cost And can be utilized as a semiconductor material.

Claims (20)

At least one metal element selected from Group 3 to Group 14 of the periodic table; And at least one chalcogen element of group 16 of the periodic table; And having a diameter or a length of 15 mm or more, wherein the large-area two-dimensional metal-chalcogen compound single crystal,
The single crystal
Placing a quartz tube sealed with the sample raw material at the center of the crystal growth furnace;
Producing a single crystal; And
Cooling the crystal growth furnace;
Lt; / RTI >
Wherein the sample material is at least one of metal elements of group 3 to group 14 of the periodic table; And
At least one chalcogen element of group 16 of the periodic table;
/ RTI >
Wherein the step of fabricating the single crystal uses a three-step temperature region formed in the crystal growth furnace,
The three-stage temperature region is sequentially formed from the raw material injection port along the depth direction of the quartz tube located at the center of the crystal growth furnace.
A crystal growth region; and
Active area ", and "
Wherein the crystal growth region is adjusted to a temperature different from the raw material region and the activation region,
The step of producing the single crystal may include:
Pre-heating the raw material region, the crystal growth region and the activation region;
Forming a temperature gradient region by lowering the temperature of the raw material region; And
Increasing the temperature of the raw material region and lowering the temperature of the crystal growth region to grow crystals;
Wherein the metal-chalcogen compound single crystals are produced by a process comprising the steps of:
The method according to claim 1,
The metal element may be at least one selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), niobium (Nb), molybdenum (Mo), technenium (Tc), ruthenium (Ru) (Cd), In, Sn, Sb, Ta, W, Re, Ir, Hg, Thal Tl), lead (Pb), and bismuth (Bi)
Wherein the chalcogen element comprises at least one element selected from the group consisting of sulfur (S), selenium (Se) and tellurium (Te).
The method according to claim 1,
Wherein the metal-chalcogen compound single crystal is a binary transition metal-chalcogenide compound represented by MX ₂ or MX (wherein M is a transition metal element of Group 3 to 12 of the periodic table and X is a chalcogen element of Group 16 of the periodic table) Chalcogen compound. ≪ / RTI >
The method according to claim 1,
Wherein the metal-chalcogen compound single crystal is represented by M _a X ' _b X _c wherein M is a transition metal element of Group 3 to 12 of the periodic table, X' and X are different from each other, and are chalcogen elements of Group 16 of the periodic table , and a, b, and c are rational numbers of 50 or less.) A large-area two-dimensional metal-chalcogen compound single crystal, wherein the compound is a ternary transition metal-chalcogen compound.
The method according to claim 1,
The metal-chalcogen compound single crystal is represented by the following formula: M _a M ' _b X _c wherein M and M' are different from each other and are a transition metal element of Group 3 to 12 of the periodic table, X is a chalcogen element of Group 16 of the periodic table , and a, b, and c are rational numbers of 50 or less.) A large-area two-dimensional metal-chalcogen compound single crystal, wherein the compound is a ternary transition metal-chalcogen compound.
The method according to claim 1,
The metal-chalcogen compound single crystal may be represented by M _a M ' _b X _c X' _d wherein M and M 'are different from each other and are a transition metal element of Group 3 to Group 12 of the periodic table, and X and X' And a quaternary transition metal-chalcogen compound represented by the following formula (1), wherein a, b, c, and d are rational numbers of 50 or less. Single crystal.
The method according to claim 1,
The metal-chalcogenide single _{crystal, FeTe, NiTe 2, CoTe 2} , MoS 2, MoTe 2, MoSe 2, TiSe 2, TiTe 2, WTe 2, WSe 2, MoS 2 (1-x) Se 2x, MoSe 2 _{(1-x) Te 2x,} WSe 2 (1-x) Te 2x, WS 2 (1-x) Te 2x, TiSe 2 (1-x) Te 2x, _{WTiSe 2, MoWTe 2, MoNbSe 2} , TiTaSe 2, MoWSe 2 (1-x) Te 2x, WTiS 2 (1-x) Se 2x, NbS 2 (1- x) Se 2x, NbSe 2 (1-x) Te _{2x, TiS 2 (1-x} ) Se 2x, ReS 2 (1-x) Se 2x, and _{ReSe 2 (1-x) Te} 2x comprising at least one from the group consisting of (wherein, x is a rational number) Large-area two-dimensional metal-chalcogenide single crystal.
Placing a quartz tube sealed with the sample raw material at the center of the crystal growth furnace;
Producing a single crystal; And
Cooling the crystal growth furnace;
Lt; / RTI >
Wherein the sample material is at least one of metal elements of group 3 to group 14 of the periodic table; And at least one chalcogen element of group 16 of the periodic table; / RTI >
The step of producing the single crystal may include a step of forming a single crystal by using a three-step temperature region formed in the crystal growth furnace, and the three-step temperature region in which a single crystal is produced, Sequentially from the raw material region; A crystal growth region; And an activation region,
Wherein the crystal growth region is adjusted to a temperature different from the raw material region and the activation region,
The step of producing the single crystal may include:
Pre-heating the raw material region, the crystal growth region and the activation region;
Forming a temperature gradient region by lowering the temperature of the raw material region; And
Increasing the temperature of the raw material region and lowering the temperature of the crystal growth region to grow crystals; / RTI >
Method for manufacturing a large-area two-dimensional metal-chalcogenide single crystal.
delete 9. The method of claim 8,
Wherein the raw material region and the crystal growth region have a temperature difference of 100 占 폚 to 200 占 폚.
9. The method of claim 8,
Wherein the activation region is controlled to a temperature equal to or different from that of the raw material region.
9. The method of claim 8,
Wherein the activation region has a temperature difference with the raw material region of 100 占 폚 or less.
delete 9. The method of claim 8,
Wherein the preheating step maintains the temperature for a period of from 40 hours to 50 hours after raising the temperature from 800C to 1200C at a rate of from 15C / h to 25C / h, A method for producing a single crystal of a cogen compound.
9. The method of claim 8,
The step of forming the temperature gradient region may include lowering the raw material region to a temperature of 600 ° C to 1000 ° C at a rate of 3 ° C / h to 5 ° C / h,
Wherein the temperature of the raw material region is lower than the temperature of the crystal growth region.
9. The method of claim 8,
Wherein growing the crystal comprises:
Raising the temperature of the raw material region from 800 ° C to 1200 ° C at a rate of 3 ° C / h to 5 ° C / h,
The crystal growth region is lowered at a rate of 3 ° C / h to 5 ° C / h to a temperature of 600 ° C to 1000 ° C,
The temperature is maintained for 15 days to 20 days after the temperature rise and fall,
The temperature of the raw material region is higher than the temperature of the crystal growth region,
Wherein the activation region has the same temperature condition as that of the raw material region.
9. The method of claim 8,
Wherein the sample material is a polycrystalline or single crystal of a metal and a chalcogen element formed by crystal growth at a temperature of 1000 ° C to 1200 ° C using Bridgman's method.
9. The method of claim 8,
The sample material may be selected from the group consisting of a halogen element, a halogenated-metal and a halogenated-chalcogen; Wherein the carrier medium further comprises at least one transport medium. ≪ RTI ID = 0.0 > 11. < / RTI >
9. The method of claim 8,
Wherein the cooling step comprises:
A first cooling step of lowering the temperature from 350 ° C to 450 ° C at a rate of 2 ° C / h to 4 ° C / h; And
A second cooling step of lowering the temperature to a room temperature at a rate of 5 ° C / h to 10 ° C / h after the first cooling step; Wherein the second metal-chalcogen compound single crystal is a single-crystal single crystal.
9. The method of claim 8,
After the cooling step, the temperature of the crystal growth region is raised by 150 to 250 DEG C higher than that of the raw material region and maintained at the temperature for 5 to 10 hours to remove unreacted starting materials and / Removing impurities; Wherein the metal-chalcogen compound single crystal further comprises a metal-chalcogenide compound.

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