JP2009035474A - Binary-alloy single crystal nanostructure and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-quality nondefective binary-alloy single crystal nanostructure having excellent solid-phase configuration, and to provide a method for producing the nanostructure through a vapor-phase synthesis method using no catalyst. <P>SOLUTION: There is provided the method for producing the binary-alloy single crystal nanostructure by utilizing a vapor phase synthesis method using the oxides of metal elements composing a binary alloy, metal substances, metal halides or binary alloy substances as a precursor, and the nanostructure produced by the method is also disclosed. In more detail, the invention provides a method of fabricating a binary alloy nanowire or nanobelt which comprises placing a precursor on the front part of a reaction furnace and a substrate on the rear part of the furnace, and heat-treating both precursor and substrate under inert gas atmosphere, and in addition, a binary alloy nanowire or nanobelt fabricated by the above method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a binary alloy single crystal nanostructure using a vapor phase synthesis method and a method for manufacturing the same.

  One-dimensional nanostructures typified by nanowires are attracting attention as materials having various application possibilities. That is, such nanostructures have their reduced size, increased aspect ratio and, on the contrary, increased volume-to-surface area ratio, new phenomena due to the new structure, or in the bulk state. It is expected to exhibit unique properties that are not observed.

  In particular, dissimilar alloy nanowires have received widespread attention as gas sensors, magnetic elements and magnetic sensors. However, the development of various and precise gas sensors is still a serious issue in the work that requires high accuracy with the development of science and technology. In addition, the development of sensors with excellent sensing capabilities is at a low level in developed countries as well as in Japan. In particular, the development of a high-sensitivity fuel cell hydrogen gas sensor that can detect the leakage of hydrogen that is expected to occur during commercialization of the fuel cell and its use as a next-generation clean energy. As a problem that must be paralleled with research on fuel cells.

  In addition, as important as the development of such hydrogen gas sensors, the development of substances used as sensor materials is as important. Among them, one of the most noticeable materials is PdAu nanowires. Using PdAu that exhibits strong adsorption power against hydrogen, it can be synthesized into nanowires and applied as a highly sensitive sensor. Furthermore, since the PdAu nanowire does not undergo an α → β phase transition at a hydrogen concentration of 0.1 to 2%, the reaction time of the sensor is expected to be improved when applied as a hydrogen sensor. Is done.

  Also, in the case of CoAg alloy nanowires, due to magnetic properties such as magnetoresistive properties and spin glass properties, in the case of silver telluride nanowires, it is a typical substance in which ions and charge conduction are mixed and has a high temperature. In the case of super telluric conductivity in the environment and Ag tellurium-rich and tellurium-rich telluride tellurium in bulk, it has a large amount of magnetoresistive MR properties. Therefore, it is expected to be utilized as a nano-sized magnetic sensor or magnetic element.

  However, in the case of a CoAg alloy, it is known that an intermetallic compound is difficult to exist because the mixing energy has a positive value in a heterogeneous system of Co and Ag. For these reasons, CoAg alloy-related papers and the like can finally be confirmed after 1990. The reported forms are thin films and nanoparticles made of amorphous or polycrystalline materials. Like CoAg, PdAu and silver telluride nanowires have never been reported to produce single-crystal nanowires, and it has also been reported that dissimilar alloy nanowires were produced by a gas phase synthesis method without a catalyst. Absent.

  Currently, it is difficult to synthesize nanowires composed of a single metal that is not a dissimilar metal nanowire, and the main interest of papers reported to date is a structure that has nano-size using bulk metal. It is a fact that focuses on the synthesis. For the synthesis of one-dimensional nanostructures, the anodic aluminum oxide template method, which is the easiest method in most research groups, is used. This method is the most convenient method for synthesizing one-dimensional nanostructures, and has attracted attention in terms of the ability to adjust the diameter of nanowires depending on the synthesis conditions (diameter control). There is a problem that it is difficult to synthesize nanowires.

  The synthesis of the single crystal nanowire is a very important element from the viewpoint of improving the electrical and magnetic properties of the material. The most important consideration in the electrical properties of the nanowires is the degree of electronic conductivity (Degree of electroconductivity). In the case of single-crystal nanowires, the nanowires themselves are one large grain boundary, so there are no obstacles to electron conduction inside the nanowires, but in the case of polycrystalline nanowires, there are many grains and grain boundaries. Therefore, when electrons are conducted along the nanowire, many boundary barriers reduce electron conductivity by causing electron scattering. In addition, when applying an external field to the nanowire, the arrangement of electron spins is a very important factor for the magnetic properties of the nanowire. As described above, since a single crystal has only one crystal, all spins of electrons are arranged in a certain direction when an external magnetic field is applied, but in the case of a polycrystalline nanowire that is an aggregate of many crystals When an external magnetic field is applied, each crystal forms an array of electron spins in various directions, which eventually acts as a factor for reducing the degree of magnetic properties.

  In order to solve such a problem, the present applicant has repeated intensive studies, and as a result, the metal oxide, metal substance or metal halide, or binary alloy substance of the metal element constituting the binary alloy is the precursor. In this way, a binary alloy nanostructure having a perfect single crystal structure could be synthesized by a vapor phase synthesis method.

  An object of the present invention to solve the above-described problems is to provide a high-quality, solid-state binary alloy single crystal nanostructure using a gas phase transport method that does not use a catalyst, and a method for producing the same.

  The method for producing a binary alloy nanostructure of the present invention includes a first material comprising a metal oxide, a metal material, or a metal halide of one metal constituting the binary alloy nanowire or the binary alloy of the nanobelt, In a second substance comprising a metal oxide, metal substance or metal halide of another metal constituting the binary alloy, or a third substance comprising a binary alloy substance of the binary alloy, Using two substances selected from one substance and a third substance, or a mixture of the two selected substances as a precursor, the precursor positioned at the front end of the reactor, and the reactor A semiconductor or non-conductor single crystal substrate positioned at an end is heat-treated in an atmosphere in which an inert gas flows to form a binary alloy single crystal nanowire or a nanobelt on the single crystal substrate. The precursor is a mixture of a first substance and a second substance, a mixture of a first substance and a third substance, or a third substance, and the metal halide of the first substance or the second substance is a fluorine. It is characterized in that it is selected from metal fluoride, metal chloride, metal bromide or metal iodide.

  The inert gas in forming the single crystal nanowire according to the present invention is flowed from 10 to 600 sccm from the front end of the reactor toward the rear end of the reactor, and the heat treatment is performed at a pressure of 2 to 30 torr. It is implemented below. The precursor is held at 500 to 1200 ° C., and the single crystal substrate is held at 700 to 1100 ° C.

  In addition, the inert gas when forming the single crystal nanobelt according to the present invention is flowed from 10 to 600 sccm from the front end of the reactor toward the rear end of the reactor, It is carried out under a pressure of 30 torr. The precursor is held at 500 to 1200 ° C., and the single crystal substrate is held at 100 to 200 ° C.

  When a metal halide is used as the precursor, that is, when the precursor is the metal halide of the first substance and the second substance, the metal halide of the first substance and the second substance Are preferably physically separated and positioned at the front end of the reactor. At this time, the metal halide of the first material is preferably maintained at 500 to 800 ° C., the second material is maintained at 800 to 1200 ° C., and the single crystal substrate is preferably maintained at 700 to 1100 ° C. .

  Preferably, the metal oxide as the first substance or the second substance is silver oxide, gold oxide, cobalt oxide, palladium oxide or tellurium oxide, and the metal substance as the first substance or the second substance is silver , Gold, cobalt, palladium or tellurium, and the metal halide as the first substance or the second substance is silver halide, gold halide, cobalt halide, palladium halide or tellurium halide, The binary alloy material as the three materials is an alloy of Pd and Au, an alloy of Co and Ag, an alloy of Ag and Te, or an alloy of Bi and Te.

Further, the binary alloy single crystal nanowire formed on the single crystal substrate is Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire, Co _y Ag _1-y ( The y is 0.01 ≦ y ≦ 0.5) single crystal nanowire, Ag ₂ Te single crystal nanowire or Bi ₁ Te ₁ single crystal nanobelt.

  The binary alloy nanostructure of the present invention is a solid solution of a single crystal of two elements selected from a metal and a metalloid produced by a gas phase synthesis method under catalytic conditions using the precursor, or It is a single crystal compound. At this time, the precursor is the binary alloy nanowire or the first substance including one metal oxide, metal substance or metal halide constituting the nanobelt, or the other metal constituting the binary alloy. A second material comprising a metal oxide, a metal material or a metal halide, or a third material comprising a binary alloy material of the binary alloy, selected from the first material to the third material Two substances, or a mixture of the two selected substances. The substrate on which the precursor is held at 500-1200 ° C. and the binary alloy single crystal nanowires are formed is held at 700-1100 ° C., and is not exposed from the precursor toward the substrate under a pressure of 2-30 torr. The binary alloy nanowire of the present invention is manufactured by a heat treatment in which an active gas flows at 10 to 600 sccm.

The binary alloy nanostructure is composed of Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire, Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0). .5) Single crystal nanowire, Ag ₂ Te single crystal nanowire, or Bi ₁ Te ₁ single crystal nanobelt. In addition, the Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire has a feature of a face centered cubic structure (FCC), and the Pd _x Au _{1 -x} (wherein x is 0.01 ≦ x ≦ 0.99) The single crystal nanowire is a solid solution. The Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single crystal nanowire has a feature of a face-centered cubic structure, and the Co _y Ag _1-y (where y is 0. 0). (01 ≦ y ≦ 0.5) The single crystal nanowire is a solid solution. In addition, the Ag ₂ Te single crystal nanowire has a simple monoclinic structure, and the Ag ₂ Te single crystal nanowire has a compound characteristic. In addition, the Bi ₁ Te ₁ single crystal nanobelt has a hexagonal structure.

  Since the production method of the present invention can produce binary alloy nanowires using a gas phase transport method without using a catalyst, the process is simple and reproducible, and the produced nanowires are perfect without defects. The single-crystal high-quality binary alloy nanowires or nanobelts have the merits and can be mass-produced with uniform-sized binary alloy nanowires or nanobelts that are not aggregated on a single-crystal substrate.

  The method for producing a binary alloy nanostructure of the present invention includes a first material including a metal oxide, a metal material, or a metal halide constituting a binary alloy nanowire or a nanobelt of the binary alloy; A second substance containing a metal oxide, metal substance or metal halide of another metal constituting the binary alloy, or a third substance containing a binary alloy substance of the binary alloy, wherein the first substance to Two precursors selected from the third substance or a mixture of the two selected substances are used as precursors, and the precursor located at the front end of the reactor and located at the rear end of the reactor The semiconductor or non-conductive single crystal substrate is heat-treated in an atmosphere where an inert gas flows to form a binary alloy single crystal nanowire or nanobelt on the single crystal substrate.

  The production method of the present invention uses a metal oxide, a metal material or a metal halide of two metals constituting a binary alloy material or a binary alloy as a precursor without using a catalyst. A method of forming a ternary alloy nanowire or nanobelt, wherein a binary alloy single crystal nanowire or nanobelt is manufactured through a gas phase mass transfer route without using a catalyst, and the process is simple and reproducible. A high-purity nanostructure that does not include impurities other than the two metals constituting the original alloy can be manufactured.

  Further, by adjusting the temperatures of the front end and the rear end of the reactor, respectively, and adjusting the degree of flow of the inert gas and the pressure in the heat treatment tube used during the heat treatment, finally Since it is a method of adjusting the nucleation driving force, growth driving force, nucleation rate and growth rate of the binary alloy above the substrate, it is possible to control the size of the binary alloy single crystal nanostructure and the density on the substrate It is possible to produce a high quality binary alloy single crystal nanostructure which is possible and has reproducibility and is excellent in crystallinity without defects.

  The temperature condition of the heat treatment, the condition of the inert gas flow (carrier gas flow rate) and the pressure condition at the time of the heat treatment can be independently changed. Accordingly, a binary alloy single crystal nanowire having a preferable quality and shape can be obtained.

  Therefore, the numerical limitation of the three conditions has an independent meaning, and it is the most desirable method for producing a binary alloy single crystal nanowire from a state in which the three conditions are matched.

  The temperatures at the front end and the rear end of the reactor are determined according to physical properties such as the melting point, vaporization point, and vaporization energy of the precursor, the flow conditions of the inert gas, and the pressure conditions during the heat treatment. Must be optimized. Preferably, the precursor is held at 500 to 1200 ° C., and in the case of nanowires, the substrate is held at 700 to 1100 ° C., and in the case of nanobelts, the substrate is preferably held at 100 to 200 ° C. .

  The inert gas preferably flows from 10 to 600 sccm from the front end of the reactor toward the rear end of the reactor. When the precursor includes a metal halide, the inert gas The active gas preferably flows from 300 to 600 sccm from the front end of the reactor toward the rear end of the reactor, and more preferably from 450 to 550 sccm. When the precursor does not contain a metal halide, the flow of the inert gas from the front end of the reactor to the rear end of the reactor is preferably 10 to 300 sccm.

  The pressure during the heat treatment is preferably lower than normal pressure, more preferably 2 to 30 torr, and most preferably 5 to 15 torr. However, when the precursor contains a metal halide, the heat treatment pressure may be normal.

  Also, the respective temperature conditions at the front and rear ends of the reactor, the inert gas flow conditions, and the pressure conditions during the heat treatment were vaporized to be transmitted to the single crystal substrate per hour and the degree of vaporization of the precursor. Amount of precursor, nucleation and growth rate of binary alloy material on single crystal substrate, surface energy of binary alloy material (nanowire or nanobelt) generated on single crystal substrate, generated on single crystal substrate This will affect the degree of aggregation of the binary alloy material (nanowire or nanobelt) and the morphology of the binary alloy material produced on the single crystal substrate.

  Therefore, by applying the vapor transport method using the precursor of the present invention based on the matching of the temperature condition, the flow of inert gas and the pressure condition at the time of heat treatment, the most preferable quality and shape can be obtained. Original alloy nanowires or nanobelts can be produced. If the conditions are outside the proper range, it is difficult to obtain a binary alloy form of nanowires, which may cause quality problems in which the produced nanowires or nanobelts are agglomerated, shape changes and defects occur. There is a problem that it is not in the form of nanowires or nanobelts but becomes a metal body such as particles or rods.

  The heat treatment time is optimized based on the matching of the temperature conditions, the flow of inert gas, the pressure conditions during the heat treatment, and the like, and preferably a heat treatment of 10 minutes to 1 hour is preferable. During the heat treatment time, the precursor vaporized by the inert gas moves to the single crystal substrate and acts on nucleation and growth, but at the same time, the binary already formed on the single crystal substrate. As a result, the binary alloy material moves between the alloy materials via the gas phase and the substrate surface (mass transfer of atoms or clusters), resulting in Ostwald ripening.

  Therefore, after the heat treatment, the density or size of the binary alloy nanowire or nanobelt is adjusted by further heat treatment in a state where the precursor of the single crystal substrate on which the binary alloy nanowire or nanobelt is formed is removed. Can do.

As described above, in the production method of the present invention, a metal oxide, a metal material, or a metal halide of two elements constituting a binary alloy nanowire or nanobelt is used as a precursor, or two of the two elements are used. The use of a binary alloy material as a precursor, and when producing binary alloy nanowires or nanobelts using the precursor, a vapor transport method can be used. Alloy single crystal nanowires or nanobelts can be produced. However, the binary alloy single crystal nanowire or nanobelt formed on the single crystal substrate is Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire, Co _y Ag _1-y (Wherein y is 0.01 ≦ y ≦ 0.5) It is preferably a single crystal nanowire, an Ag ₂ Te single crystal nanowire, or a Bi ₁ Te ₁ single crystal nanobelt.

  Also, the precursors used to produce the binary alloy nanowires or nanobelts are in the form of a mixture, or include two metals that make up the binary alloy, but use two materials that are separated but not in a mixed state be able to. When the above mixture is used, a mixture of the first substance and the second substance, or a mixture of the first substance and the third substance can be used as the precursor, and the binary alloy nanowire or the nanobelt is constituted alone. It is also possible to use an alloy of two metals (third substance). The mixture of the first substance and the second substance includes a metal oxide of the first substance and a metal oxide of the second substance, a metal substance of the first substance and a metal oxide of the second substance, and a halogenation of the first substance. Metal and metal oxide of second substance, metal oxide of first substance and metal substance of second substance, metal substance of first substance and metal substance of second substance, metal halide of first substance and second substance Metal material of the first material, metal oxide of the second material and metal halide of the second material, metal material of the first material and metal halide of the second material, or metal halide of the first material and halogen of the second material It can also be a mixture in which a metal halide is mixed. In the present embodiment, preferably, the metal oxide of the first material and the metal oxide of the second material, the metal material of the first material and the metal oxide of the second material, the metal oxide of the first material and the second metal oxide. The metal substance of the substance or a mixture of the metal substance of the first substance and the metal substance of the second substance is used.

  Also, the mixture of the first material and the third material may be a binary alloy material of the first material metal oxide and the third material, a first material metal material and the third material binary alloy material, or the first material. It can also be a mixture in which the metal halide of the material and the binary alloy material of the third material are mixed. However, preferably, the first material metal oxide and the third material binary alloy material or the first material metal material and the third material binary alloy material are used.

  Also, a binary alloy material of the third material can be used alone as the precursor.

  The mixing state of the mixture does not only mean that the first substance and the second substance having a particle form are mixed with each other, but the two substances are adjacent to each other on the reactor (the same temperature is maintained). It is meant to include being placed at a certain position.

  In particular, when a metal halide is used as a precursor, when the metal halide of the first material and the second material are used, the front end of the reactor is in a state where the two materials are physically separated. It is preferable to be located at. Here, the reason why the metal halide of the first material and the second material are physically separated from each other at the front end of the reactor is that the metal halide of the first material, the second material, This is because each of them is accommodated in different crucibles and acts on the synthesis of nanowires or nanobelts while maintaining different temperatures. This is because the volatility of the metal halide is higher than that of metals, different metals and metal oxides, so that the amount of metal halide gas moving on the substrate according to the flow of the inert gas is reduced. It is for adjusting. In this case, as the precursor, the metal halide of the first substance and the metal oxide of the second substance, the metal halide of the first substance and the metal substance of the second substance, or the metal halide of the first substance and the second substance. Although the metal halide of the substance is used, preferably, the metal halide of the first substance and the metal oxide of the second substance, or the metal halide of the first substance and the metal substance of the second substance are used. Also, a metal halide of the first material and a binary alloy material of the third material can be used. In the metal halide of the first material and the second material (or the third material) that are physically separated from the front end of the reaction furnace as described above, the metal halide of the first material Is held at 500 to 800 ° C., and the second substance (or third substance) is preferably held at 800 to 1200 ° C. In the case of nanowires, the substrate is held at 700 to 1100 ° C. In this case, the substrate is preferably held at 100 to 200 ° C. At this time, when the temperature control device constituting the reactor is a single, the precursor is positioned in a uniform zone in the tube, and the distance between the precursor and the uniform zone is adjusted to adjust the distance between the precursor and the uniform zone. The temperature can be adjusted by positioning the substance or substrate. Moreover, when providing a heating body and a temperature control apparatus separately, the temperature which it is going to hold | maintain can be adjusted using a temperature control apparatus and a heating body, respectively.

  The metal halide of the first substance or the second substance is selected from metal fluoride, metal chloride, metal bromide or metal iodide, preferably silver halide, gold halide, cobalt halide Palladium halide or tellurium halide. The silver halide is selected from silver fluoride, silver chloride, silver bromide or silver iodide, and the gold halide is selected from gold fluoride, gold chloride, gold bromide or gold iodide. The cobalt halide is selected from cobalt fluoride, cobalt chloride, cobalt bromide or cobalt iodide, and the palladium halide is palladium fluoride, palladium chloride, palladium bromide. Or, it is selected from palladium iodide, and the tellurium halide is selected from tellurium fluoride, tellurium chloride, tellurium bromide or tellurium iodide.

  The metal oxide of the first substance or the second substance is preferably silver oxide, gold oxide, cobalt oxide, palladium oxide or tellurium oxide. At this time, the gold oxide, cobalt oxide, palladium oxide or tellurium oxide may be an oxide having a thermodynamically stable stoichiometric ratio at normal temperature and pressure, and may be a point defect due to metal or a point defect due to oxygen. May not have the above-mentioned stable stoichiometric ratio.

  The metal material of the first material or the second material is preferably silver, gold, cobalt, palladium, or tellurium.

  The binary alloy material of the third material is preferably an alloy of Pd and Au, an alloy of Co and Ag, an alloy of Ag and Te, or an alloy of Bi and Te, and the alloy of Pd and Au, Co and The alloy of Ag or the alloy of Ag and Te can be an intermetallic compound, a compound, or a solid solution. Further, the composition of the alloy is preferably similar to the composition of the nanowire or nanobelt to be manufactured, but may be different from the composition of the nanowire or nanobelt to be manufactured.

  The semiconductor or non-conductor single crystal substrate can be used as long as it is a chemically / thermally stable semiconductor or non-conductor under the above heat treatment conditions, but preferably a silicon single crystal, Group 4 single crystal selected from germanium single crystal or silicon germanium single crystal, Group 3-5 single crystal selected from gallium arsenide single crystal, Indium phosphorus single crystal, or Gallium phosphorus single crystal, Group 2-6 It is preferable to use a single crystal substrate selected from a single crystal, a group 4-6 single crystal, a sapphire single crystal or a silicon dioxide single crystal.

  However, since the substrate simply serves to provide a space in which nanowires or nanobelts are formed on the upper portion of the substrate, a polycrystalline body of the above-described single crystal substrate material may be used if necessary.

In order to prove the superiority of the manufacturing method of the present invention through experiments, according to the manufacturing method of the present invention, Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire, Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single-crystal nanowires, Ag ₂ Te single-crystal nanowires, and Bi ₁ Te ₁ single-crystal nanobelts were manufactured (Examples 1, 2, 3, and 4), respectively. .

  Example 1 below is a representative example of producing a binary alloy nanowire without using a halogenated precursor, and Example 2 is a binary alloy nanowire using a halogenated precursor. Example 3 is a representative example of manufacturing a binary alloy nanowire using the binary alloy material of the binary alloy nanowire to be manufactured. Example 4 is a representative example of manufacturing a binary alloy nanobelt using the binary alloy material of the binary alloy nanobelt to be manufactured.

In Example 3 described later, only a binary alloy material (Ag ₂ Te) is used as a precursor, but a binary alloy material (Ag ₂ Te) and a metal (Ag) or a binary alloy material are used. A metal oxide (Ag ₂ O ₃ ) can be mixed and used. In Example 4 to be described later, only a binary alloy material (Bi ₁ Te ₁ ) is used as a precursor, but a binary alloy material (Bi ₁ Te ₁ ) and a metal (Bi) or a binary alloy are used. A substance and a metal oxide (Bi ₂ O ₃ ) can be mixed and used.

Example 1
In a reaction furnace, Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowires were synthesized by a vapor transport method.

  The reactor is divided into a front end portion and a rear end portion, and is configured by individually providing a heating body and a temperature control device. The tube in the reactor was made of quartz material having a diameter of 1 inch and a length of 60 cm.

A mixture obtained by mixing 0.03 g of a precursor Au ₂ O ₃ (Sigma-Aldrich, 334057 product) and 0.03 g of PdO (Sigma-Aldrich, 203971 product) in the front end of the reactor. The housed boat container made of high-purity alumina was positioned. A sapphire single crystal substrate (surface 0001) was positioned in the rear end of the reactor. Argon gas is introduced from the front end of the reactor and exhausted to the rear end of the reactor. A vacuum pump is installed at the rear end of the reactor so that the pressure in the quartz tube is maintained at 5 torr using the vacuum pump so that 150 sccm of Ar flows using an MFC (Mass Flow Controller). did.

The temperature at the front end of the reactor (alumina boat containing the precursor) is maintained at 1100 ° C., and the temperature at the rear end of the reactor (silicon substrate) is maintained at 950 ° C. for 30 minutes. Thus, Pd _x Au _1-x (wherein x is 0.01 ≦ x ≦ 0.99) single crystal nanowires were manufactured.

(Example 2)
In the reaction furnace, Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single crystal nanowires were synthesized by a vapor transport method.

  A reactor configured in the same manner as in Example 1 was used.

CoCl ₂ (Sigma-Aldrich, 449776 product) 0.01 g and Ag ₂ O (Sigma-Aldrich, 22163 product) 0.3 g were used as precursors, and the CoCl ₂ and Ag ₂ O were each made of high-purity alumina material. Was placed in a boat-type container and positioned at the front end of the reactor. In addition, a Si single crystal substrate (surface 100) was positioned in the rear end of the reactor. Further, an alumina crucible containing Au ₂ O ₃ was positioned in the front end of the reactor.

  Argon gas is introduced from the front end of the reactor and exhausted to the rear end of the reactor. A vacuum pump was installed at the rear end of the reactor, and the pressure inside the quartz tube was maintained at 15 torr using the vacuum pump so that 500 sccm of Ar flowed using MFC.

The temperature of the front end of the reactor (position in the reactor) is kept at 1000 ° C. so that the alumina crucible containing the Ag ₂ O is kept at 1000 ° C., and the Ag ₂ O is contained. The alumina crucible containing the CoCl ₂ is positioned at an interval of 4 cm with respect to the position of the alumina crucible so that the alumina crucible containing the CoCl ₂ maintains a temperature of 650 ° C. At the same time, the temperature of the rear end (silicon substrate) of the reactor is kept at 800 ° C. for 30 minutes by heat treatment for 30 minutes to produce Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single crystal. Nanowires were manufactured. In order to understand this example, the structure of the heat treatment in the precursor and substrate of Example 2 is shown in FIG.

(Example 3)
Ag ₂ Te single crystal nanowires were synthesized by a vapor transport method in a reaction furnace.

  A reactor configured in the same manner as in Example 1 was used.

A boat-type vessel made of high-purity alumina material in which 0.05 g of Ag ₂ Te (Sigma-Aldrich, 400635 product) as a precursor was accommodated was positioned in the front end of the reaction furnace. A silicon single crystal substrate (surface 100) was positioned in the rear end of the reactor. Argon gas is introduced from the front end of the reactor and exhausted to the rear end of the reactor. A vacuum pump was installed at the rear end of the reactor, and the pressure inside the quartz tube was maintained at 10 torr using the vacuum pump, and 200 sccm of Ar was allowed to flow using MFC.

The temperature of the front end of the reactor (alumina boat containing the precursor) is kept at 1000 ° C., and the temperature of the rear end of the reactor (silicon substrate) is kept at 800 ° C. for 30 minutes. Produced Ag ₂ Te single-crystal nanowires.

Example 4
In the reaction furnace, Bi ₁ Te ₁ single crystal nanobelts were synthesized by a vapor transport method.

  A reactor configured in the same manner as in Example 1 was used.

A boat-type vessel made of high-purity alumina material containing 0.05 g of Bi ₂ Te ₃ (Alfa Aesar, 44077 product) as a precursor was placed in the front end of the reactor. A silicon single crystal substrate (surface 100) was positioned in the rear end of the reactor. Argon gas is introduced from the front end of the reactor and exhausted to the rear end of the reactor. A vacuum pump was installed at the rear end of the reactor, and the pressure inside the quartz tube was maintained at 10 torr using the vacuum pump, and 200 sccm of Ar was allowed to flow using MFC. The temperature of the front end of the reactor (alumina boat containing the precursor) is maintained at 600 ° C., and the temperature of the rear end of the reactor (silicon substrate) is maintained at 150 ° C. for 30 minutes. Bi ₁ Te ₁ single crystal nanobelts were manufactured by

  As described above, the binary alloy single crystal nanowires and nanobelts manufactured according to Examples 1 to 4 are analyzed, and the quality, shape, purity, and the like of the binary alloy single crystal nanostructures manufactured by the manufacturing method of the present invention are determined. Investigated and analyzed.

First, FIGS. 2 to 5 show the results of analyzing and measuring Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowires manufactured through Example 1. FIG.

FIG. 2 is an SEM photograph of Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) nanowires manufactured on a sapphire single crystal substrate. As can be seen from FIG. 2, the diameter of a large amount of nanowires is about 50 to 150 nm, and is manufactured separately from a sapphire single crystal substrate with a uniform size having a length of 30 μm or more (30 to 50 μm). I understand. In addition, nanowires having a shape extending straight in the longitudinal direction of the nanowires and capable of being individually separated without the aggregation of the nanowires are manufactured, and the longitudinal axis of the nanowires is substantially perpendicular to the surface of the substrate. It turns out that it has orientation.

FIG. 3 shows the result of XRD (X-Ray Diffraction) of Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) nanowires. The diffraction result of FIG. 3 shows that the Pd metal and the Au metal have crystallinity that does not match. FIG. 5 is a component analysis result of nanowires using EDS (Energy Dispersive Spectroscopy) attached to the TEM equipment of FIG. 4. FIG. As can be seen here, it is possible to confirm that the manufactured nanowire is composed of only Pd and Ag by excluding the incidentally measured substances due to the characteristics of the measurement equipment such as the grid. In addition, as a result of analysis by EDS in which a large number of nanowires manufactured by the manufacturing method of the present invention are mounted on a TEM equipment, nanowires of Pd _x Au _1-x are manufactured, where x is 0.01 ≦ x ≦ 0. It is found that it has a composition of 99.

FIG. 5 is a TEM analysis result of Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) nanowire, and FIG. 5A is a dark field image of the nanowire. 5 (b) is a high-magnification TEM photograph of the nanowire in FIG. 5 (a), and FIG. 5 (c) is a SAED (Selected Area Electron Diffraction) pattern of the nanowire in FIG. 5 (a). Through FIG. 5A and FIG. 5B, it can be confirmed that nanowires having a smooth surface and a uniform thickness are formed, and manufactured through FIG. 5C. It can be confirmed that the nanowire has a face-centered cubic structure and a single crystal having a growth direction of [100].

  Through the results shown in FIGS. 2 to 5, it is confirmed that a nanowire having a perfect shape and high quality as a single crystal having a feature of a face-centered cubic structure in which Pd and Au form a solid solution is manufactured. can do.

6 to 8 show the results of analysis and measurement of Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single crystal nanowires manufactured according to Example 2. FIG.

FIG. 6 is an SEM photograph of Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single crystal nanowires manufactured on a silicon single crystal substrate. As can be seen from FIG. 6, the nanowire and the plate are manufactured at the same time. As can be seen from the high-magnification SEM photograph shown in the upper left part of FIG. 6, the diameter is about 200 to 300 nm and the length is several um or more. It can be confirmed that the nanowires of uniform size are separated from the sapphire single crystal substrate and are manufactured in large quantities. It can be confirmed that nanowires that have a shape extending straight in the longitudinal axis direction and that are not separated from each other and that can be individually separated are manufactured. As can be seen from the XRD diffraction results of FIG. 7, it can be seen that the manufactured nanowires have a face-centered cubic structure (FCC) and are consistent with the diffraction results of bulk Ag.

FIG. 8 is a dark field image of the Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) nanowire, and the inset shown in the lower left part of FIG. 8 shows the nanowire of FIG. SAED pattern. As can be seen from the results of FIG. 8, it is understood that the nanowire is a single crystal having a [01-1] growth direction of a face-centered cubic structure (FCC).

FIG. 9 shows the component analysis result of the nanowire using EDS mounted on the TEM equipment, FIG. 9A shows the result of Ag EDS mapping of the nanowire of FIG. 9, and FIG. 9B shows the result of FIG. It is a result of Co EDS mapping of 9 nanowires. 9C shows the EDS result of the white square portion displayed on the upper part of the nanowire of FIG. 9, and FIG. 9D shows the EDS result of the white square portion displayed on the lower side. As can be seen from FIGS. 9A to 9D, if the materials measured incidentally are excluded due to the characteristics of the measurement equipment such as the grid, the manufactured nanowires are composed of only Co and Ag. It can be seen that Co and Ag are uniformly distributed throughout the nanowire. The analysis results of a large number of nanowires EDS manufactured by the manufacturing method of the present invention, the nanowires produced in Co _y Ag _1-y, wherein y is a composition of 0.01 ≦ y ≦ 0.5 I know that.

  Through the results shown in FIGS. 6 to 9, a high-quality and perfect-shaped nanowire is manufactured as a single crystal having a face-centered cubic structure in which Co and Ag form a solid solution.

10 to 13 show measurement results for Ag ₂ Te nanowires manufactured through Example 2. FIG.

FIG. 10 is an SEM photograph of Ag ₂ Te nanowires manufactured on a sapphire single crystal substrate. As can be seen from FIG. 10, the diameter of a large amount of nanowires is about 150 to 200 nm, and the length is several um or more. It can be seen that the sapphire single crystal substrate has a uniform size and is manufactured separately. In addition, nanowires that have a shape that extends straight in the longitudinal direction of the nanowires and that can be separated individually without the aggregation of the nanowires are manufactured. It can be seen that Ag ₂ Te nanowires, which are simple monoclinic compounds having the same structure as bulk Ag ₂ Te, are produced through the XRD results of FIG.

FIG. 12 is a TEM analysis result of the Ag ₂ Te nanowire, FIG. 12A is a dark field image and a SAED pattern of the nanowire, and FIG. 12B is a HRTEM (High) of the nanowire of FIG. It is a Resolution Transmission Microscopy photograph, and the pattern inserted in the upper right part of FIG. 12B is the Fast Fourier Transform pattern of FIG. 12B. Through FIG. 12A, it is confirmed that a nanowire having a smooth surface, a uniform size nanowire is formed, and the manufactured nanowire is a simple monoclinic single crystal having a [−302] growth direction. be able to. The nanowire manufactured through the HRTEM photograph of FIG. 12B is a high-quality single crystal body having no defects, and the distance between the (010) planes of the nanowire is the same as the distance between the bulk Ag ₂ Te (010) planes. .46A can be confirmed. As can be seen from the result of component analysis of nanowires using EDS attached to the TEM equipment of FIG. 13, if the incidentally measured substances are excluded due to the characteristics of the measurement equipment such as a grid, the manufactured nanowires It can be confirmed that it is composed only of Ag and Te, and the composition ratio of Ag and Te is 2: 1.

10 to 13, a simple monoclinic structure compound in which Ag and Te have a composition ratio of 2: 1, and a perfect shape and high quality single crystal Ag ₂ Te nanowires are manufactured. I know that.

FIG. 14 shows a TEM analysis result of the Bi ₁ Te ₁ nanobelt, and (a) shows a dark field image and an SAED pattern of the nanobelt.

  It can be confirmed through FIG. 14A that a nanobelt having a smooth surface and a uniform thickness is formed. FIG. 14B is a high-magnification TEM photograph of the nanobelt, and the inserted image is a fast Fourier transform pattern.

  It can be confirmed that the nanobelt synthesized by (a) and (b) of FIG. 14 has a hexagonal structure and is a single crystal having a growth direction of [110].

  FIG. 15 is a result of component analysis of a nanobelt using EDS attached to a TEM equipment of a nanobelt manufactured according to Example 4 of the present invention.

  FIG. 16 is a graph showing the XRD results of the nanobelt manufactured according to Example 4 of the present invention.

It is a schematic diagram of the heat processing structure of the precursor of Example 2 of this invention and a board | substrate. It is a SEM photograph figure of the nanowire manufactured by Example 1 of the present invention. It is a XRD result figure of the nanowire manufactured by Example 1 of this invention. FIG. 4 is a result diagram of an EDS attached to a TEM equipment of nanowires manufactured according to Example 1 of the present invention. It is a TEM analysis result figure of the nanowire manufactured by Example 1 of the present invention, (a) is a dark field image of the nanowire, (b) is a high magnification TEM photograph of the nanowire of (a), (C) is a drawing showing the SAED pattern of the nanowire of (a). It is a SEM photograph figure of the nanowire manufactured by Example 2 of the present invention. FIG. 6 is an XRD result diagram of a nanowire manufactured according to Example 2 of the present invention. FIG. 7 is a dark field image of a nanowire manufactured according to Example 2 of the present invention, and the drawing inserted in the lower part on the left side of the drawing shows a SAED pattern of the nanowire. FIG. 6 is a component analysis result diagram of nanowires using EDS attached to a TEM equipment of nanowires manufactured according to Example 2 of the present invention, wherein (a) is a diagram of Ag EDS mapping of nanowires; (b) Is the result of Co EDS mapping of the nanowire, (c) is the EDS result of the white square part displayed on the top of the nanowire, and (d) is the EDS result of the white square part displayed at the bottom. is there. It is a SEM photograph figure of the nanowire manufactured by Example 3 of the present invention. FIG. 6 is an XRD result diagram of nanowires manufactured according to Example 3 of the present invention. FIG. 4 is a TEM analysis result diagram of nanowires manufactured according to Example 3 of the present invention, where (a) is a drawing showing a dark field image and SAED pattern of nanowires, and (b) is a HRTEM of nanowires of (a). The pattern inserted in the upper right part of (b) is a drawing showing the fast Fourier transform pattern of (b). FIG. 6 is a result diagram of an EDS attached to a TEM equipment of nanowires manufactured according to Example 3 of the present invention. A TEM analysis diagram of Bi ₁ Te ₁ nanobelt a diagram showing (a) shows nanowires dark field image and SAED pattern. FIG. 6 is a component analysis result diagram of a nanobelt using EDS attached to a TEM equipment of a nanobelt manufactured according to Example 4 of the present invention. It is a graph which shows the result of XRD of the nanobelt manufactured by Example 4 of this invention.

Claims (26)

A metal oxide of one metal constituting the binary alloy of the binary alloy nanowire or nanobelt, a first substance comprising a metal material or a metal halide, a metal oxide of another metal constituting the binary alloy, In a second substance comprising a metal substance or a metal halide, or a third substance comprising a binary alloy substance of the binary alloy,
Using two substances selected from the first substance and the third substance, or a mixture of the two selected substances as a precursor,
The precursor positioned at the front end of the reaction furnace and the semiconductor or non-conductor single crystal substrate positioned at the rear end of the reaction furnace are heat-treated in an atmosphere where an inert gas flows, A method for producing a binary alloy nanostructure comprising forming a binary alloy single crystal nanowire or a nanobelt.   The binary alloy nanostructure according to claim 1, wherein the precursor is a mixture of a first material and a second material, a mixture of a first material and a third material, or a third material. Body manufacturing method.   The metal halide of the first material or the second material may be selected from metal fluoride, metal chloride, metal bromide, or metal iodide. The method for producing a binary alloy nanostructure according to claim 1, wherein:   2. The method for producing a binary alloy nanostructure according to claim 1, wherein the inert gas flows from 10 to 600 sccm from a front end portion of the reaction furnace toward a rear end portion of the reaction furnace.   The method of manufacturing a binary alloy nanostructure according to claim 4, wherein the heat treatment is performed under a pressure of 2 to 30 torr.   The method for producing a binary alloy nanostructure according to claim 5, wherein the precursor is held at 500 to 1200 ° C, and the single crystal substrate is held at 700 to 1100 ° C.   The method for producing a binary alloy nanostructure according to claim 5, wherein the precursor is held at 500 to 1200 ° C, and the single crystal substrate is held at 100 to 200 ° C.   The precursor is the metal halide of the first material and the second material, and physically separates the metal halide of the first material and the second material to form the front end of the reactor. The method for producing a binary alloy nanostructure according to claim 1, wherein the method is positioned.   The metal halide of the first material is maintained at 500 to 800 ° C., the second material is maintained at 800 to 1200 ° C., and the single crystal substrate is maintained at 700 to 1100 ° C. The method for producing a binary alloy nanostructure according to claim 8.   The metal alloy as the first substance or the second substance is silver oxide, gold oxide, cobalt oxide, palladium oxide, or tellurium oxide, The binary alloy nanostructure according to claim 1, Method.   The method for producing a binary alloy nanostructure according to claim 1, wherein the metal material as the first material or the second material is silver, gold, cobalt, palladium, or tellurium.   The binary alloy according to claim 1, wherein the metal halide as the first substance or the second substance is silver halide, gold halide, cobalt halide, palladium halide or tellurium halide. A method for producing a nanostructure.   2. The binary according to claim 1, wherein the binary alloy material as the third material is an alloy of Pd and Au, an alloy of Co and Ag, an alloy of Ag and Te, or an alloy of Bi and Te. A method for producing an alloy nanostructure. The binary alloy single crystal nanowire formed on the single crystal substrate is a Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire, Co _y Ag _1-y (where y Is a single-crystal nanowire, an Ag ₂ Te single-crystal nanowire, or a Bi ₁ Te ₁ single-crystal nanobelt, wherein the binary alloy nanostructure according to claim 1 is manufactured. Method.   Binary alloy nanostructures that are single-crystal solid solutions or compounds of single crystals of two elements selected from metals and metalloids prepared by gas phase synthesis under catalytic conditions using precursors body.   The precursor includes a metal oxide of one metal constituting the binary alloy nanowire or nanobelt, a first material including a metal substance or a metal halide, and a metal oxide of another metal constituting the binary alloy. A second substance comprising a metal substance or a metal halide, or a third substance comprising a binary alloy substance of the binary alloy, two substances selected from the first substance to the third substance; The binary alloy nanostructure according to claim 15, wherein the binary alloy nanostructure is a mixture of the two selected substances.   In the gas phase synthesis method, the precursor is held at 500 to 1200 ° C., and the substrate on which the binary alloy single crystal nanowire is formed is held at 700 to 1100 ° C., and the pressure is 2 to 30 torr. The binary alloy nanostructure according to claim 15, wherein the binary alloy nanostructure is a heat treatment in which an inert gas flows from a precursor to the substrate toward the substrate by 10 to 600 sccm.   In addition, the vapor phase synthesis method includes maintaining the precursor at 500 to 1200 ° C. and maintaining the substrate on which the binary alloy single crystal nanobelt is formed at 100 to 200 ° C. under a pressure of 2 to 30 torr. The binary alloy nanostructure according to claim 15, wherein the binary alloy nanostructure is a heat treatment in which an inert gas flows from the precursor to the substrate toward the substrate by 10 to 600 sccm. The binary alloy nanostructure is composed of Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire, Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0). .5) The binary alloy nanostructure according to claim 15, wherein the binary alloy nanostructure is a single crystal nanowire, an Ag ₂ Te single crystal nanowire, or a Bi ₁ Te ₁ single crystal nanobelt. The Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire has a face centered cubic (FCC) structure, according to claim 19. Binary alloy nanostructure. 21. The binary alloy nanostructure according to claim 20, wherein the Pd _x Au _1-x (where x is 0.01 ≦ x ≦ 0.99) single crystal nanowire is a solid solution. The binary alloy nanostructure according to claim 19, wherein the Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single crystal nanowire has a face-centered cubic structure. 23. The binary alloy nanostructure according to claim 22, wherein the Co _y Ag _1-y (where y is 0.01 ≦ y ≦ 0.5) single crystal nanowire is a solid solution. The Ag ₂ Te single crystal nanowires, binary alloy nanostructure according to claim 19, characterized in that a simple monoclinic structure (Simple monoclinic). The binary alloy nanostructure according to claim 24, wherein the Ag ₂ Te single crystal nanowire is a compound. The Bi ₁ Te ₁ single-crystalline metal nanobelt is binary alloy nanostructure according to claim 19, characterized in that the structure of hexagonal (hexagonal).