WO2018186535A1

WO2018186535A1 - Method for preparing two-dimensional material by using adsorption inhibitory surface treatment

Info

Publication number: WO2018186535A1
Application number: PCT/KR2017/006884
Authority: WO
Inventors: 안지훈; 전우진; 정성준
Original assignee: 한국해양대학교 산학협력단
Priority date: 2017-04-06
Filing date: 2017-06-29
Publication date: 2018-10-11

Abstract

The present invention relates to a method for preparing a two-dimensional material of which the electrical properties are improved by increasing a crystalline size by adopting an adsorption inhibitor. More specifically, disclosed is a method for preparing a two-dimensional material by using an adsorption inhibitory surface treatment, the method comprises the steps of: (1) adopting an adsorption inhibitor in a substrate having adsorption sites so as to adsorb the adsorption inhibitor thereon; (2) forming, by using atomic layer deposition, a two-dimensional material on the adsorption sites on which the adsorption inhibitor has not been adsorbed; and (3) crystallizing the formed two-dimensional material. The method for preparing a two-dimensional material by using an adsorption inhibitory surface treatment, according to the present invention, has the effects of: obtaining a two-dimensional material in the form of a thin film that is uniform with respect to a wide area; enabling a plastic material, which is vulnerable to heat, to be freely applied to a substrate as the method is performed at a low processing temperature; and increasing the crystallinity of a two-dimensional material, thereby being capable of preparing a two-dimensional material having excellent charge mobility.

Description

Method for producing two-dimensional material using adsorption inhibition surface treatment

The present invention relates to a method for producing a two-dimensional material that improves the electrical properties by increasing the crystal size by the introduction of the adsorption inhibitor.

Two-dimensional materials represented by graphene, silicene, phosphorine, hexagonal boron nitride, and metal chalcogenides are planar interatomic bonds. Refers to a material made of strong covalent bonds, while weak van der Waals bonds to the other out of phase.

These two-dimensional materials can be formed very thin (<1 nm) in molecular layers because of the nature of their bonding. In addition, it exhibits much higher charge mobility and photo-electronic conversion efficiency than conventional semiconductor materials, and has the advantage of making transparent and flexible materials. Therefore, it is expected to be widely used as the next-generation electronic device and photoelectric device. Basic and applied researches on this are being actively conducted.

In order to apply a two-dimensional material to electronic devices and products, a synthesis method for obtaining a uniform thin film over a large area is required. The easiest way to obtain the same is by using a mechanical peeling method or a chemical peeling method. When using these methods, there are advantages in that various two-dimensional materials can be easily obtained, but there are problems in that reproducibility is insufficient and it is impossible to obtain a uniform thin film on a wafer scale.

In addition, recently, chemical vapor deposition (CVD) has been proposed as a method for obtaining two-dimensional materials. However, the CVD method makes it easy to obtain a few millimeters of flakes, but it is not possible to obtain a uniform material on a wafer scale (~ 10 cm) and is susceptible to heat because it requires a high process temperature of 600 ° C or higher. There is a problem that the application of the substrate of the plastic material is limited.

Therefore, atomic layer deposition has been mentioned as the only alternative as a process for mass production of electronic devices and products using two-dimensional materials. However, there is a problem in that the crystal size of the two-dimensional material is very small due to the characteristics of the atomic layer deposition method, and the electrical properties thereof are very low compared to the known ones.

The present invention is to provide a method for producing a two-dimensional material having a uniform thin film form over a large area, and to provide a method for producing a two-dimensional material having excellent crystal structure and charge mobility while using an atomic layer deposition method. For that purpose.

In order to achieve the above object, the present invention comprises the steps of (1) adsorbing the adsorption inhibitor by introducing an adsorption inhibitor to the substrate having an adsorption site (adsorption site); (2) forming a two-dimensional material at an adsorption site where the adsorption inhibitor is not adsorbed by using atomic layer deposition; And (3) crystallizing the formed two-dimensional material. It provides a method for producing a two-dimensional material using an adsorption inhibiting surface treatment comprising a.

In the method for producing a two-dimensional material using the adsorption-inhibiting surface treatment according to the present invention, it is possible to obtain a two-dimensional material having a uniform thin film form over a large area, and to apply at a low process temperature to apply a plastic substrate that is weak to heat. As the crystal structure of the two-dimensional material is improved, the two-dimensional material having excellent charge mobility can be produced.

Figure 1 shows the comparison of the metal precursor adsorption behavior, three-dimensional reaction formula and the reaction energy in the manufacturing process of the two-dimensional material according to Examples 1-2 and Comparative Examples 1-2.

Figure 2 shows the results of measuring the adsorption density of the metal precursor in the manufacturing process of the two-dimensional material according to Example 1 and Comparative Example 2.

Figure 3 shows the Raman analysis of the two-dimensional material according to Example 1 and Comparative Example 2.

Figure 4 shows the results of measuring the adsorption density of the metal precursor in the manufacturing process of the two-dimensional material according to Example 1 and Example 2.

5 shows XPS analysis results for the two-dimensional material according to Example 1 and Comparative Examples 1 and 2;

Figure 6 shows the results of the AFM analysis for the two-dimensional material according to Examples 1-2 and Comparative Examples 1-2.

7 shows measurement results of a ratio of particles having an average diameter and a diameter of 10 nm or more with respect to the two-dimensional material according to Examples 1 and 2.

8 is a transmission microscope (TEM) photograph of a side portion of a two-dimensional material according to Example 2 and Comparative Examples 1 to 2;

9 is a transmission microscope (TEM) photograph of a planar portion of a two-dimensional material prepared according to Example 2 and Comparative Example 1. FIG.

FIG. 10 illustrates a result of measuring bottom gate voltage (V _g ) -drain current (I _ds ) of a FET including a two-dimensional material manufactured according to Comparative Example 1. FIG.

FIG. 11 shows a result of measuring bottom gate voltage (V _g ) -drain current (I _ds ) of a FET including a two-dimensional material prepared according to Example 2. FIG.

The present invention relates to a method for preparing a two-dimensional material having improved crystal size by the introduction of an adsorption inhibitor to improve electrical properties, and to a method for producing a two-dimensional material showing high crystallinity and charge mobility while using atomic layer deposition. It is about.

As used herein, the term 'adsorption site' refers to a functional group present on the surface of the substrate, and refers to a site where a precursor or the like may be adsorbed onto the substrate by reacting with a precursor of a two-dimensional material. .

The ALD reactor described herein is used in the manufacturing process of the two-dimensional material and is not specifically described in the embodiments of the present invention, but will be easily understood by those skilled in the art. It is made up of possible configurations.

According to one aspect of the invention, (1) adsorbing the adsorption inhibitor by introducing an adsorption inhibitor to the substrate having an adsorption site (adsorption site); (2) forming a two-dimensional material at an adsorption site where the adsorption inhibitor is not adsorbed by using atomic layer deposition; And (3) crystallizing the formed two-dimensional material. It provides a method for producing a two-dimensional material using an adsorption inhibiting surface treatment comprising a.

First, step (1) of adsorbing the adsorption inhibitor will be described.

The substrate may be any substrate, and may be a rigid or flexible substrate. For example, it may be a glass substrate, a plastic substrate, or a substrate made of another material, and a substrate made of a transparent plastic material may be used if necessary. In a preferred embodiment, the substrate may be a SiO ₂ / Si substrate. In addition, the substrate is characterized by having an 'adsorption site' on its surface. In addition to the adsorption site, precursors of two-dimensional materials can be adsorbed, as well as adsorption inhibitors and adsorption activators, which will be described later.

The adsorption inhibitor refers to a material that is treated on the surface of the substrate before the two-dimensional material is adsorbed on the substrate, and means a material that serves to prevent the precursor of the two-dimensional material from adsorbing to the adsorption site of the substrate. The type of the adsorption inhibitor is not particularly limited as long as it prevents the precursor of the two-dimensional material from adsorbing to the adsorption site of the substrate. Specific examples thereof include alcohol compounds having 1 to 10 carbon atoms, perylene-3,4,9,10-tetra -Tetracarboxylic acid tetra potassium salt (PTAS), copper (II) 1, 2, 3, 4, 8, 9, 10, 11, 15, 16, 17, 18,22,23,24,25-hexadecafluoro-29H, 31H-phthalocyanine {copper (II) 1,2,3,4,8,9,10,11,15,16,17, 18,22,23,24,25-hexadecafluoro-29H, 31H-phthalocyanine: F ₁₆ CuPc}, perylene-3,4,9,10-tetracarboxylic dianhydride {perylene-3,4,9,10-tetracarboxylic acid dianhydride: PTCDA}, copper (II) phthalocyanine {copper (II) phthalocyanine: CuPc}, dibenzo {(f, f ′)-4,4 ′, 7,7′-tetraphenyl} diindeno (1,2,3-cd: 1 ′, 2 ′, 3′-lm) perylene [dibenzo {(f, f ′)-4,4 ′, 7,7′-tetraphenyl} diindeno (1,2, 3-cd: 1 ′, 2 ′, 3′-lm) perylene: DBP], crystal violet (CV)}, p P-nitrobenzene-diazo-amino-azobenzene (NAA), N, N'-bis (3-methylphenyl) -N, N'-diphenyl-9,9'- Spirobi [fluorene] -2,7-diamine {N, N'-Bis (3-methylphenyl) -N, N'-diphenyl-9,9'-spirobi [fluorene] -2,7-diamine: spiro-TPD}, tris (4-carbazoyl-9-ylphenyl) amine {tris (4-carbazoyl-9-ylphenyl) amine: TCTA}, bashocuproine {bathocuproine: BCP} and diethyl sulfide : DES). As a preferred embodiment of the present invention, diethyl sulfide (DES) may be used as an adsorption inhibitor.

1 shows a comparison of metal precursor adsorption behavior, three-dimensional reaction formula and reaction energy according to the presence or absence of pretreatment in the manufacturing process of the two-dimensional material according to Examples 1 and 2 and Comparative Examples 1 and 2. Hereinafter, the mechanism of the adsorption inhibitor will be described with reference to FIG. 1.

As can be seen in Figure 1, the adsorption site is present at a specific density on the surface of the substrate, when using the ALD method is the most important factor in determining the growth behavior of the initial thin film. The precursor of the two-dimensional material is adsorbed to the adsorption site according to a specific probability affected by chemisorption kinetics, and even when applying an adsorption inhibitor or an adsorption activator to the substrate, respectively Adsorbed on the site.

When adsorption inhibitors or adsorption activators are adsorbed to the adsorption sites of the substrate, they exhibit different adsorption behavior for precursors of two-dimensional materials because they are chemically different from the adsorption sites that are not pretreated. The adsorption activator forms new covalent bonds with the functional groups of the adsorption site, but is adsorbed on the substrate, but forms relatively unstable bonds, thereby increasing the reactivity of the adsorption site thereby increasing the adsorption probability of the two-dimensional material precursor. On the other hand, since the adsorption inhibitor covalently bonds with the functional group of the adsorption site to form a relatively stable bond, it lowers the reactivity of the adsorption site, thereby reducing the adsorption probability of the two-dimensional material precursor.

Step (1) may be performed at a temperature of 200 to 500 ° C, preferably 250 to 450 ° C, more preferably 300 to 400 ° C. If the temperature of step (1) is less than 200 ℃, there is a problem that the adsorption inhibitor is difficult to be sufficiently adsorbed on the adsorption site, when the temperature exceeds 500 ℃ there is a problem that the use of a substrate weak in heat.

In addition, step (1) may be performed for 10 to 300 seconds, preferably 10 to 250 seconds, more preferably 10 to 200 seconds. If the advancing time of step (1) is less than 10 seconds, there is a problem in that the adsorption inhibitor is not sufficiently adsorbed, and if it exceeds 300 seconds, the excess adsorption inhibitor is adsorbed so that the two-dimensional material is not sufficiently formed.

Next, step (2) of forming the two-dimensional material will be described.

Step (2) is characterized by atomic layer deposition. The atomic layer deposition method refers to a nano thin film deposition technique using a monoatomic layer phenomenon, it is possible to deposit an ultrafine thin film having an atomic layer thickness.

A two-dimensional material refers to a material composed of weak van der Waals bonds on the other side of the out-of-phase bonds, whereas the planar interatomic bonds are made of strong covalent bonds, specifically, graphene and silicene. ), Phosphorene, hexagonal boron nitride, and metal chalcogenides. As a preferred embodiment of the present invention, the metal chalcogenide compound may be used as a two-dimensional material.

Metal chalcogenide compounds consist of metals and chalcogen elements. As a preferred embodiment of the present invention, the metal chalcogenide compound is at least one metal selected from the group consisting of Mo, W, Nb, Ga, Ta, Zr, Ti, Hf, Sn, In and Ge, S, Se and Te It may be composed of one or more chalcogen elements selected from the group consisting of.

In another embodiment, the metal chalcogenide compound may have a chemical formula of MX, MX ₂ or M ₂ X ₃ . In the above formula, M is a metal, preferably Mo, W, Nb, Ga, Ta, Zr, Ti, Hf, Sn, In and Ge may be any one selected from the group consisting of. In the above formula, X is a chalcogen element, and preferably may be any one selected from the group consisting of S, Se, and Te. Specific examples include MoS, MoS ₂ , Mo ₃ S ₂ , MoSe, MoSe ₂ , Mo ₃ Se ₂ , MoTe, MoTe ₂ , Mo ₃ Te ₂ , WS, WS ₂ , W ₃ S ₂ , WSe, WSe ₂ , W ₃ Se ₂ , WTe, WTe ₂ , W ₃ Te ₂ , NbS, NbS ₂ , Nb ₃ S ₂ , NbSe, NbSe ₂ , Nb ₃ Se ₂ , NbTe, NbTe ₂ , Nb ₃ Te ₂ , GaS, GaS ₂ , Ga ₃ S ₂ , GaSe, GaSe ₂ , Ga ₃ Se ₂ , GaTe, GaTe ₂ , Ga ₃ Te ₂ , TaS, TaS ₂ , Ta ₃ S ₂ , TaSe, TaSe ₂ , Ta ₃ Se ₂ , TaTe, TaTe ₂ , Ta ₃ Te ₂ , ZrS, ZrS ₂ , Zr ₃ S ₂ , ZrSe, ZrSe ₂ , Zr ₃ Se ₂ , ZrTe, ZrTe ₂ , Zr ₃ Te ₂ , TiS, TiS ₂ , Ti ₃ S ₂ , TiSe, TiSe ₂ , Ti ₃ Se ₂ , TiTe, TiTe ₂ , Ti ₃ Te ₂ , HfS, HfS ₂ , Hf ₃ S ₂ , HfSe, HfSe ₂ , Hf ₃ Se ₂ , HfTe, HfTe ₂ , Hf ₃ Te ₂ , SnS, SnS ₂ , Sn ₃ S ₂ , SnSe, SnSe ₂ , Sn ₃ Se ₂ , SnTe, SnTe ₂ , Sn ₃ Te ₂ , InS, InS ₂ , In ₃ S ₂ , InSe, InSe ₂ , In ₃ Se ₂ , InTe, InTe ₂ , In ₃ Te ₂ , GeS, GeS ₂ , Ge ₃ S ₂ , GeSe, GeSe ₂ , Ge ₃ Se ₂ , GeTe, GeTe _2, and Ge ₃ Te ₂ , but are not limited thereto. A preferred embodiment is MoS ₂ . Can be used.

When using a metal chalcogenide compound as a two-dimensional material as a preferred embodiment of the present invention, step (2) is (a) introducing a metal precursor into the reactor to the metal adsorption site where the adsorption inhibitor is not adsorbed Adsorbing; (b) purging the metal precursor from inside the reactor; (c) introducing a chalcogen precursor into the reactor to synthesize a metal chalcogenide compound; And (d) purging the chalcogenide precursor from the inside of the reactor.

Step (2) may be carried out at a temperature of 100 to 400 ℃, preferably at a temperature of 150 to 350 ℃, more preferably 200 to 300 ℃. In addition, step (2) may be performed for 60 to 240 seconds, preferably 80 to 200 seconds, more preferably 100 to 160 seconds. When the temperature and the execution time of step (2) satisfy the above range, it is possible to effectively form a two-dimensional material.

Next, step (3) for crystallizing the two-dimensional material will be described.

Since the two-dimensional material formed by step (2) has insufficient crystal size, post deposition annealing is performed to induce crystallization. Step (3) may be performed at a temperature of 350 to 500 ° C, preferably 400 to 500 ° C, more preferably at a temperature of 420 to 480 ° C. In addition, step (3) may be performed for 5 to 120 seconds, preferably 5 to 90 seconds, more preferably 5 to 60 seconds. When the temperature and the performance time of step (3) satisfy the above range, it is possible to effectively induce the crystallization of the two-dimensional material.

According to a preferred embodiment of the present invention step (1) to (3) may be carried out at a temperature of 500 ℃ or less. When forming a two-dimensional material by the conventional CVD method requires a high process temperature of 600 ℃ or more, there was a limitation in applying a substrate of a material susceptible to heat. However, the present invention by the ALD method can form a thin film of a two-dimensional material at a relatively low temperature, has the advantage that can be applied to a substrate of various materials as needed.

Two-dimensional material, according to an embodiment of the present invention the average particle size (hereinafter, d _grain) 20 to be 120 ㎚, and preferably from 25 to 100 ㎚, more preferably of from 30 to 80 ㎚ d _grain Can have When the d _grain of the two-dimensional material satisfies the above range, a two-dimensional material having an excellent crystal structure can be obtained.

In addition, the proportion of particles having a particle size of 10 nm or more (hereinafter, c _grain ) among the particles constituting the two-dimensional material may be 20 to 100%, preferably 25 to 98%, more preferably 30 to 95% Can be. When the c _grain of the two-dimensional material satisfies the above range, it is possible to obtain a two-dimensional material showing excellent charge mobility.

The excellent electrical properties of the two-dimensional material are due to the excellent crystal structure of the two-dimensional material, and securing an excellent crystal structure becomes an important factor for improving the electrical properties. The crystal structure of the two-dimensional material depends on the concentration of precursor adsorbed at the initial stage of formation of the two-dimensional material. The precursor concentration of the adsorbed two-dimensional material directly affects the nuclear density of the two-dimensional material on the surface of the substrate, and d _grain and c _grain of the crystal structure of the two-dimensional material according to the increase or decrease of the nuclear density of the two-dimensional material. This is greatly affected.

When the two-dimensional material is formed on the substrate which has not been treated with the adsorption inhibitor, the nuclear density of the two-dimensional material increases because the precursor of the two-dimensional material is sufficiently adsorbed on the substrate. If the nuclear density is increased, the crystal structure of the two-dimensional material does not grow enough to form a thin film. However, when treating the adsorption inhibitor, the concentration at which the precursor of the two-dimensional material is adsorbed on the substrate is reduced, resulting in a decrease in nuclear density. If the nuclear density is reduced, the crystal structure of the two-dimensional material is fully grown, which can dramatically improve d _grain and c _grain . When the d _grain and c _grain of the crystal structure forming the two-dimensional material is improved as described above, a thin film of the two-dimensional material having a uniform and continuous layer structure can be obtained, and as described later, a uniform and continuous layer structure can be obtained. It is possible to greatly improve the electrical properties of the two-dimensional material.

The two-dimensional material according to the preferred embodiment of the present invention may be characterized by forming a continuous layered structure. The layered structure has a structure of about 3 to 10 layers, and may preferably have a layered structure of 5 to 8 layers, more preferably 6 to 7 layers. In addition, it can be characterized by forming a continuous layered structure without interruption over a length of about 150nm or more, and the number of laminated layers is homogeneous.

On the other hand, when the thin film of the two-dimensional material is formed by the ALD method without pretreatment of the adsorption inhibitor, the crystal structure does not grow sufficiently or includes an amorphous portion, thereby forming a non-continuous layered structure. As such, when the layered structure is not continuous, it may negatively affect the carrier movement process, which may cause deterioration of electrical characteristics.

However, since the two-dimensional material according to the preferred embodiment of the present invention has a continuous layer structure and does not exhibit a decrease in carrier mobility, it is possible to obtain a two-dimensional material having excellent electrical properties.

Hereinafter, the present invention will be described in more detail with reference to Examples.

These examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples in accordance with the gist of the present invention.

<실시예><Example>

실시예 1Example 1

Adsorption inhibitor pretreatment was performed on the substrate using an ALD reactor. The pretreatment step was performed at 350 ° C. for 30 seconds, using a SiO ₂ / Si substrate, and using DES (Sigma-Aldrich) as the adsorption inhibitor. The bubbler type canister for DES was maintained at 35 ° C. during the pretreatment. DES was introduced into the reactor with Ar carrier gas and the chamber pressure was maintained at 0.5 torr. After performing the pretreatment, the substrate was moved to a loadlock chamber to prevent contamination due to air exposure. The DES remaining in the reactor was then purged with Ar gas and the chamber susceptor was cooled to 250 ° C. for the next step.

Next, a metal precursor and a sulfur precursor were introduced into a substrate pretreated with DES to form a metal chalcogenide compound. Mo (CO) ₆ (UP Chemical) was used as a metal precursor, and diethyl disulfide (hereinafter referred to as DEDS, Sigma-Aldrich) was used as a sulfur precursor. Formation of the metal chalcogenide compound was composed of four steps of 'metal precursor supply, Ar purification, sulfur precursor supply and Ar purification', and was performed for 0.5 seconds, 60 seconds, 3 seconds and 60 seconds, respectively. The pressure in the reactor was maintained at 0.5 torr and the reaction temperature was maintained at 250 ° C. The metal precursor was introduced without using a carrier gas by heating the canister to 35 ° C. In addition, the sulfur precursor was introduced into the reactor at a flow rate of 100 sccm (standard cubic centimeters per minute) using pure Ar carrier gas (99.999%), and a bubbler-type canister heated to 65 ° C was used.

Finally, post deposition annealing was performed to induce crystallization of the metal chalcogenide compound. A metal heat treatment system was used, and an MoS ₂ thin film was prepared by heat treatment for 30 seconds under Ar atmosphere and 450 ° C.

실시예Example 2 2

A MoS ₂ thin film was prepared in the same manner as in Example 1 except that the pretreatment step using DES was performed for 150 seconds.

비교예Comparative example 1 One

A MoS ₂ thin film was prepared in the same manner as in Example 1 except that the pretreatment step using DES was not performed.

비교예Comparative example 2 2

The pretreatment was performed for 150 seconds using the adsorption activator DEDS instead of the adsorption inhibitor DES, and the same as in Example 1 except that the bubbler type canister for DEDS was maintained at 60 ° C. during the pretreatment. MoS ₂ thin film was prepared by the method.

<시험예><Test Example>

컴퓨터 계산을 이용한 반응 에너지 계산Reaction energy calculation using computer calculation

For Examples 1 and 2 and Comparative Examples 1 and 2, the relevant reaction energy was calculated using the Vienna Ab initio Simulation Package (VASP). Generalized gradient approximation for exchange-correlation interactions was applied, and by default, plane waves with kinetic energy below 400 eV were included. Ion position has been updated until you exceed this 0.02eV / Å residual force (residual forces), the electron density is the total energy change 10 ^- eased until the excess of ⁵ eV. All calculations were performed at the gamma point, and the tridymite structure was adapted to cover with isolated silanol groups where surface adsorption was most advantageous. In addition, the unit cell is set large enough to minimize spurious interactions between the cells.

Figure 1 shows the comparison of the metal precursor adsorption behavior, the three-dimensional reaction equation and the reaction energy in the manufacturing process of the two-dimensional material according to Examples 1 and 2 and Comparative Examples 1 and 2 according to. Hereinafter, the effect of the DES preprocessing will be described with reference to FIG. 1.

The surface of the SiO ₂ / Si substrate is covered with —OH functional groups that serve as adsorption sites. In Comparative Example 1 in which a metal precursor is adsorbed without DES or DEDS pretreatment, OH bonds are broken through reaction between the metal precursor Mo (CO) ₆ and the adsorption site (—OH group), and Mo and O form covalent bonds. The metal precursor can thereby be adsorbed.

In Examples 1 and 2 undergoing DES pretreatment as an adsorption inhibitor, DES reacts with the adsorption site to release ethane thiol to form a covalent bond between oxygen (O) and carbon (C). Since the OC bond thus formed corresponds to a relatively stable bond, it was shown that the reaction in which the metal precursor Mo (CO) ₆ was adsorbed to the DES pretreated adsorption site was thermodynamically undesirable. In addition, the adsorption site pretreated with DES is expected that the tightly bound ethyl group can block the access of Mo (CO) ₆ in three dimensions to further reduce the reactivity.

On the other hand, in Comparative Example 2 undergoing DEDS pretreatment as an adsorption activator, DEDS reacts with the adsorption site and ethane thiol is released to form a covalent bond between oxygen (O) and sulfur (S). Since the OS bonds formed as described above correspond to relatively unstable bonds, the reactivity with Mo (CO) ₆ , which is a metal precursor, is increased. As a result, Mo and S form a covalent bond, and more metal precursors can be adsorbed.

From the above results, it can be seen that the chemisorption of Mo (CO) ₆ , a metal precursor, is favored kinematically when pretreated with DEDS, and passivation of the adsorption site by forming stable CO bonds when pretreated with DES. It was confirmed that the adsorption of Mo (CO) ₆ was suppressed.

Raman 분석 평가Raman analysis evaluation

Raman analysis was performed about Examples 1-2 and Comparative Example 2.

Figure 2 shows the results of measuring the adsorption density of the metal precursor in the manufacturing process of the two-dimensional material according to Example 1 and Comparative Example 2. Referring to FIG. 2, Mo adsorption density was found to be very low in Example 1 after DES pretreatment. However, in the case of Comparative Example 2 subjected to DEDS pretreatment, as the cycle of the ALD process was increased, the Mo adsorption density was increased almost linearly to clearly confirm the difference in reactivity.

Figure 3 shows the Raman analysis of the two-dimensional material according to Example 1 and Comparative Example 2. Referring to FIG. 3, in the case of Example 1 which was subjected to DES pretreatment, a wide peak was observed around 1500 cm ⁻¹ , unlike the case of Comparative Example 2. This indicates CC bonding, and in Example 1, the surface of the substrate is coated with a composite carbon compound.

Figure 4 shows the results of measuring the adsorption density of the metal precursor in the manufacturing process of the two-dimensional material according to Example 1 and Example 2. Referring to FIG. 4, it can be seen that the Mo adsorption density is lower as the pretreatment process time by DES is longer, and in particular, when the DES pretreatment time is 10 seconds or more, the Mo adsorption density is remarkably lowered.

From the above results, it was confirmed that adsorption of the Mo precursor can be suppressed when the DES pretreatment.

XPSXPS 분석 평가 Analytical Evaluation

X-ray photoelectron spectroscopy (XPS) analysis was performed to confirm and evaluate the chemical structure and stoichiometry of the two-dimensional material prepared according to Example 1, Comparative Examples 1 and 2.

5 shows XPS analysis results for the two-dimensional material according to Example 1 and Comparative Examples 1 and 2; Referring to FIG. 5, in the case of Example 1 which was subjected to DES pretreatment, only peaks corresponding to MoS ₂ were confirmed. In addition, since the Mo 3d peak moved below the binding energy (BE) value and the intensity of the O 1s peak decreased, it was confirmed that the formation of MoO _x was greatly reduced.

However, in the case of Comparative Example 1 that did not undergo pretreatment, although MoS ₂ predominantly existed, it was confirmed that a certain amount of MoO _x also existed.

From the above results, it was confirmed that the formation of MoS ₂ is increased when the DES pretreatment is performed, and the formation of MoO _x is effectively suppressed.

AFMAFM 분석 평가 Analytical Evaluation

In order to evaluate the particle size and the like of the two-dimensional material prepared according to Examples 1 and 2 and Comparative Examples 1 and 2 were analyzed by an atomic force microscope (AFM).

Figure 6 shows the results of the AFM analysis for the two-dimensional material according to Examples 1-2 and Comparative Examples 1-2. Thus it was obtained the video image of the surface morphology of samples, via the computer calculated the average diameter of the particles _(grain d) and the particle size of the coverage of the particles less than 10㎚ (c _grain). The results are summarized in Table 1 below.

Table 1

	Example 1	Example 2	Comparative Example 1	Comparative Example 2
Average diameter (nm)	28.49	75.47	19.53	3.01
Coverage (%)	33.2	93.2	15.0	3.0

In addition, Figure 7 shows the measurement results for the ratio of the average diameter of the particles to the two-dimensional material according to Example 1 and Example 2 and the particles having a diameter of 10nm or more.

6, 7 and Table 1, Examples 1 and 2 subjected to DES pretreatment showed d _grains of 28.49 nm and 75.47 nm, respectively, and 32.2% and 93.16% c _grains , respectively.

However, Comparative Example 1, which did not undergo pretreatment, showed only 19.53 nm of d _grain and 15.0% of c _grain , while Comparative Example 2, which had undergone DEDS pretreatment, decreased d _grain to 3.01 nm and c _grain of 3.0. The results were reduced by%. Therefore, in Examples 1 and 2 subjected to the DES pretreatment it was confirmed that the d _grain and c _grain increased significantly.

These results can be explained as follows. In the case of DES pretreatment, the nucleation of MoS ₂ is suppressed at the initial stage of ALD due to the inhibition of adsorption of the Mo precursor, and when the nuclear density is reduced, the MoS ₂ crystal has a relatively large particle size.

However, DEDS pretreatment increases the adsorption of Mo precursors, which increases the nucleation of MoS ₂ at the early stage of ALD. Thus, when the nuclear density is increased, MoS ₂ crystals have a relatively small particle size.

Results can be successfully controlled with the crystal structure of MoS ₂ thin film by modifying the surface of the substrate through the DES pre From the above, and to determine that they can form a MoS ₂ thin film of excellent crystal structure having a relatively large particle size there was.

TEMTEM 분석 평가 Analytical Evaluation

Transmission microscope (TEM) analysis was performed on the two-dimensional materials prepared according to Example 2 and Comparative Examples 1 and 2.

8 is a transmission microscope (TEM) photograph of a side portion of a two-dimensional material according to Example 2 and Comparative Examples 1 to 2, and FIG. 9 is a view of a two-dimensional material prepared according to Example 2 and Comparative Examples 1 to 2; Transmission microscopy (TEM) images of planar sections. 8 to 9, although all the samples have almost the same thickness corresponding to about 5 to 7 layers, it can be seen that the microstructure is different from sample to sample.

In Example 2, after the DES pretreatment, the layered structure parallel to the substrate can be clearly observed. In addition, it can be seen that a continuous layer structure is formed throughout the region (about 150 nm) that can be seen from the TEM photograph, the number of laminated layers is homogeneous, and no amorphous phase is observed.

However, in the case of Comparative Example 1, which was not subjected to pretreatment, a partial layer structure was observed, but the number of laminated layers varied, and thus it was confirmed that they were not continuously connected. This means that the MoS ₂ particles are not well connected on the entire thin film, which may negatively affect the carrier migration process and cause electrical properties to deteriorate.

In the case of Comparative Example 2, which was subjected to DEDS pretreatment, the layered structure could not be confirmed, and only randomly scattered small flake layers were identified. Referring to the XPS analysis of Comparative Example 2, a considerable amount of MoO _x was mixed, it can be understood that the higher the MoO _x ratio hinders the growth of the MoS ₂ structure, and thus a continuous layered structure cannot be formed. have.

From the above results, it was confirmed that when MoS ₂ was deposited by the ALD method after the DES pretreatment, it was possible to produce a uniform and continuous layered structure.

FET 제조 및 전기적 특성 평가FET Fabrication and Electrical Characterization

In order to evaluate the electrical properties of the two-dimensional material prepared according to Example 2 and Comparative Examples 1 and 2, a bottom gate field effect transistor (FET) including an Au / Ti electrode and a 200 nm wide SiO ₂ gate insulator was manufactured. .

10 and 11 show the results of measuring the bottom gate voltage (V _g ) -drain current (I _ds ) of the FET including the two-dimensional material according to Comparative Example 1 and Example 2, respectively. Referring to FIGS. 10 and 11, Example 2 subjected to DES pretreatment showed a high field effect hole mobility of 11.8 cm ² V ⁻¹ s ⁻¹ at room temperature to clearly show typical n-type characteristics.

However, Comparative Example 1, which did not undergo pretreatment, exhibited a p-channel characteristic with a field effect hole mobility of about 0.004 cm ² V ⁻¹ s ⁻¹ . Relatively low mobility appears to be due to small particle size and structural heterogeneity, and the p-type characteristic appears to be derived from MoO _x . It was also confirmed that Comparative Example 2, which had been subjected to DEDS pretreatment, did not exhibit significant switching behavior.

After the pre-treatment DES from the above results and to improve the crystal structure forming the thin film when depositing the MoS ₂ by the ALD method, so MoS _2, depending It was confirmed that the electrical properties of the thin film can be improved.

As described above, the present invention has been described by means of a limited embodiment, but the present invention is not limited thereto, and the technical idea of the present invention and the claims described below by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the range of equality.

Claims

(1) adsorbing said adsorption inhibitor by introducing an adsorption inhibitor into a substrate having an adsorption site;

(2) forming a two-dimensional material at an adsorption site where the adsorption inhibitor is not adsorbed by using atomic layer deposition; And

(3) crystallizing the formed two-dimensional material; manufacturing method of a two-dimensional material using the adsorption inhibiting surface treatment comprising a.
The method of claim 1,

The adsorption inhibitor is an alcohol compound having 1 to 10 carbon atoms, perylene-3,4,9,10-tetracarboxylic acid tetra potassium salt (PTAS), copper ( II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H, 31H-phthalocyanine {copper ( II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H, 31H-phthalocyanine: F 16 CuPc}, perylene- 3,4,9,10-tetracarboxylic dianhydride {perylene-3,4,9,10-tetracarboxylic acid dianhydride: PTCDA}, copper (II) phthalocyanine {copper (II) phthalocyanine: CuPc}, dibenzo {(f, f ')-4,4', 7,7'-tetraphenyl} diindeno (1,2,3-cd: 1 ', 2', 3'-lm) perylene [dibenzo {( f, f ′)-4,4 ′, 7,7′-tetraphenyl} diindeno (1,2,3-cd: 1 ′, 2 ′, 3′-lm) perylene: DBP], crystal violet (crystal violet ( CV)}, p-nitrobenzene-diazo-amino- azobenzene {p-nitrobenzene-diazo-amino-azobenzene: NAA}, N, N'-bis (3-methylphenyl-N, N'-diphenyl-9 , 9'-spa Robi [fluorene] -2,7-diamine {N, N'-Bis (3-methylphenyl) -N, N'-diphenyl-9,9'-spirobi [fluorene] -2,7-diamine: spiro- TPD}, tris (4-carbazoyl-9-ylphenyl) amine {tris (4-carbazoyl-9-ylphenyl) amine: TCTA}, vasocuproin {bathocuproine: BCP} and diethyl sulfide (DES) Method for producing a two-dimensional material using the adsorption inhibiting surface treatment, characterized in that any one selected from the group consisting of.
The method of claim 1,

The two-dimensional material is any one selected from the group consisting of graphene, silicene, phosphorene, hexagonal boron nitride and metal chalcogenides Method for producing a two-dimensional material using the adsorption inhibiting surface treatment, characterized in that.
The method of claim 3,

The metal chalcogenide compound is at least one metal selected from the group consisting of Mo, W, Nb, Ga, Ta, Zr, Ti, Hf, Sn, In and Ge, and at least one selected from the group consisting of S, Se and Te Method for producing a two-dimensional material using the adsorption inhibiting surface treatment, characterized in that the compound consisting of chalcogen element.
The method of claim 3,

The metal chalcogenide compound is a method for producing a two-dimensional material using the adsorption inhibitory surface treatment, characterized in that MoS 2 .
The method of claim 1,

Method for producing a two-dimensional material using the adsorption inhibiting surface treatment, characterized in that the proportion of the particles having a particle size of 10nm or more of the particles forming the two-dimensional material is 30 to 95%.
The method of claim 1,

(2) forming the two-dimensional material,

(a) introducing a metal precursor into the reactor to adsorb the metal to an adsorption site where the adsorption inhibitor is not adsorbed;

(b) purging the metal precursor from inside the reactor;

(c) introducing a chalcogen precursor into the reactor to synthesize a metal chalcogenide compound; And

(d) purging the chalcogenide precursor from the inside of the reactor.
The method of claim 1,

Step (1) to (3) is a method for producing a two-dimensional material using the adsorption inhibiting surface treatment, characterized in that carried out at a temperature of 100 to 500 ℃.
(1) introducing and adsorbing diethyl sulfide (DES), an adsorption inhibitor, onto a substrate having an adsorption site;

(2) forming a metal chalcogenide compound at an adsorption site where the adsorption inhibitor is not adsorbed by atomic layer deposition; And

(3) crystallizing the formed metal chalcogenide compound.
The method of claim 9,

The metal chalcogenide compound is a method for producing a two-dimensional material using the adsorption inhibitory surface treatment, characterized in that MoS 2 .