KR100540511B1 - Core-shell structured zinc oxide nanowire and preparation thereof - Google Patents

Abstract

The present invention relates to a zinc oxide nanowire having a multi-wall structure and a method for manufacturing the same. A multi-wall (core-shell) prepared by coating various heterogeneous materials such as metal, semiconductor, and dielectric on a zinc oxide nanowire according to the present invention. Zinc oxide nanowires have a multi-functional nanowire structure that can be fabricated in a single line for easy integration, and can manufacture core components of various nano-devices. It can be used advantageously.

Description

Zinc oxide nanowire of multi-wall structure and its manufacturing method {CORE-SHELL STRUCTURED ZINC OXIDE NANOWIRE AND PREPARATION THEREOF}             

1 is a basic structural diagram of a zinc oxide nanowire having a multi-wall structure according to the present invention, and a nanodevice using the same.

(a) is a structural diagram of a zinc oxide (ZnO) nanowire having a multi-wall structure,

(b) is a structural diagram of a nano device such as a rectifier, a light emitting diode (LED), a photo-detector device, etc. using a zinc oxide nanowire having a multi-wall structure,

(c) is a structural diagram of a nano device such as a high electron mobility transistor (HEMT), spintronics, etc. using a zinc oxide nanowire having a multi-wall structure;

2 is a scanning electron microscope (SEM) photograph of a zinc oxide nanowire and a zinc oxide nanowire having a multi-wall structure according to the present invention.

(a) is a scanning electron micrograph of a zinc oxide nanowire,

(b) to (d) are multi-walled zinc magnesium oxide (ZnMgO) / oxidation prepared by coating zinc magnesium oxide (ZnMgO), titanium oxide (TiO ₂ ) and gallium nitride (GaN) on zinc oxide nanowires, respectively. Scanning electron micrographs of zinc (ZnO), titanium oxide (TiO ₂ ) / zinc oxide (ZnO), and gallium nitride (GaN) / zinc oxide (ZnO) nanowires,

3 is a transmission electron micrograph (TEM) of a zinc oxide nanowire having a multi-wall structure according to the present invention,

(a) is a transmission electron micrograph of a multi-walled gallium nitride (GaN) / zinc oxide (ZnO) nanowire,

(b) is a transmission electron microscope photograph of a heterostructure in which a gallium nitride nanotube obtained by removing a part of the multiwall nanowire and a gallium nitride / zinc oxide nanowire having a multiwall structure are joined.

The present invention relates to a zinc oxide nanowire having a multi-wall structure and a method for manufacturing the same, and specifically, prepared by coating various heterogeneous materials such as metals, semiconductors, and derivatives on zinc oxide nanowires prepared by organometallic deposition. A zinc oxide nanowire having a multi-wall structure.

Nano-sized semiconductor materials up to 100 nm exhibit not only various physical properties depending on the type of material, but also quantized energy levels are formed according to the size of the optical and electrical properties such as absorption and emission wavelengths depending on the size. Change (blue shift), quantized conductance, Coulomb blockade, and the like.

In addition, one-dimensional semiconductor nanomaterials, such as semiconductor nanorods and nanowires, have a large aspect ratio and are easy to artificially manipulate, and exhibit various physical properties according to the type of material, and also control electric conductivity and band gap by adding foreign materials. It is attracting attention as a building block of next-generation nano devices using a bottom up method because it is easy and emits light. In particular, field effect transistors (FETs), photo-detector devices, bio-chemical sensors, non-volatile memory devices using such one-dimensional semiconductor nanomaterials, as well as p-type and n A variety of nano devices such as diodes, rectifiers, logic devices, and light emitting diodes using type nanowires have begun to receive much attention.

However, the conventional nano devices have a problem in that device implementation and integration are very difficult because of the use of nano materials having a single structure, and performance is also low. To overcome this problem, it is necessary to develop a technology capable of realizing various nanostructures that can satisfy a desired function as a single nanowire (multi-walled nanowire).

Accordingly, an object of the present invention is to provide a multi-walled zinc oxide-based nanowires, and a method of manufacturing the same, which can realize nanostructures having various functions by coating various materials on the zinc oxide nanowires as a single nanowire. It is.

In order to achieve the above object, in the present invention, a zinc oxide / transition metal-based material, zinc oxide / nitride semiconductor or zinc oxide / dielectric such as a transition metal-based material, a nitride semiconductor or a dielectric material coated on a zinc oxide nanowire A zinc oxide nanowire having a wall structure is provided.

The present invention also provides a method for producing a zinc oxide nanowire having a multi-wall structure, including coating a transition metal, a nitride semiconductor or a dielectric on the zinc oxide nanowires produced by organometallic chemical vapor deposition.

Hereinafter, the present invention will be described in more detail.

Specifically, the zinc oxide nanowires having a multi-wall structure according to the present invention are coated with various heterogeneous materials according to the intended use while controlling the thickness on the zinc oxide nanowires prepared by organometallic chemical vapor deposition. It is characterized by obtaining in the form of a single nanowire.

In the method according to the present invention, the material coated on the zinc oxide-based nanowires is not particularly limited, and according to the intended use, such as bandgap adjustment, electric conductivity control, magnetic material addition, new nanowire or nanotube formation, etc. Various materials can be used in various ways.

For example, the material coated on the zinc oxide nanowires to control the band gap may include magnesium (Mg), cadmium (Cd), and the like, and these metals may be coated on the zinc oxide nanowires to form zinc oxide (ZnO). Zinc oxide (Zn _1-x Mg _x O, 0 <x <1) or zinc cadmium oxide (Zn _1-x Cd _x O, 0 <x <1) Can be.

Manganese (Mn), cobalt (Co) and the like are used to make the magnetism, and according to the present invention by coating these transition metals on the zinc oxide nanowires zinc oxide doped with manganese or cobalt oxide Zinc manganese (Zn _1-x Mn _x O, 0 <x <1) or zinc cobalt (Zn _1-x Co _x O, 0 <x <1) and the like can be prepared.

In addition, a nitride semiconductor such as GaN, AlN, InN, or an alloy thereof may be coated on the zinc oxide nanowires to form new nanowires (nanotubes), and titanium oxide (TiO ₂ ) and nitride to control electrical conductivity. Zinc oxide nanowires having a multi-wall structure coated with a dielectric such as titanium (TiN), silicon oxide (SiO ₂ ), and barium titanium oxide (BaTiO ₃ ) may be prepared.

In the method of the present invention, the method of coating the heterogeneous materials on the zinc oxide nanowires may include chemical vapor deposition, sputtering, thermal or electron beam evaporation, including organometallic chemical vapor deposition, As well as physical growth methods such as pulse laser deposition, as well as conventional thin film formation methods known in the art, such as a vapor-phase transport process using a metal catalyst such as gold, may be used. Preferably, an organometallic chemical vapor deposition method for producing nanowires using a magnetic coupling mode without a metal catalyst may be used.

The zinc oxide nanowires used in the present invention are injected with zinc-containing organometallic and oxygen-containing gas or oxygen-containing organics into the reactor via separate lines, respectively, and have a pressure of 10 ^-5 to 760 mmHg and a temperature of 400 to It is prepared by an organometallic chemical vapor deposition method characterized in that the precursors of the reactants are chemically reacted under the reaction conditions of 900 ℃ to deposit and grow zinc oxide-based nanowires on the substrate. Zinc-containing organometallics used in the present invention include dimethyl zinc [Zn (CH ₃ ) ₂ ], diethyl zinc [Zn (C ₂ H ₅ ) ₂ ], zinc acetate [Zn (OOCCH ₃ ) ₂ H ₂ O. ], Zinc acetate anhydride [Zn (OOCCH ₃ ) ₂ ], zinc acetylacetonate [Zn (C ₅ H ₇ O ₂ ) ₂ ], and the like.

In addition, the oxygen-containing gas used in the present invention may include O ₂ , O ₃ , NO ₂ , water vapor, CO ₂ and the like, the oxygen-containing organic substance may include C ₄ H ₈ O, The diameter, length and density of the zinc oxide nanowires prepared according to the present invention can be variously adjusted according to the growth temperature, pressure and flow rate of the reactant.

The zinc oxide nanowires having a multi-wall structure can be prepared by coating a heterogeneous material using various precursors known in the art, preferably using organometallic chemical vapor deposition on the prepared zinc oxide nanowires.

In other words, by injecting the reaction precursors of the material to be coated into the reactor through separate lines, and chemically reacting under a reaction condition of a pressure of 10 ^-5 to 760 mmHg and a temperature of 400 to 900 ℃, heterogeneous materials on the zinc oxide nanowires Can be coated. When chemically reacted at the above pressure and temperature ranges, the material to be coated is well grown on the zinc oxide nanowires at an appropriate density. In addition, when coating at about 500 ℃ 5 minutes to 10 minutes, when coating at 800 to 900 ℃ 30 minutes to 1 hour is preferably performed, the coating film thickness increases in proportion to the growth time reaction time The time was maintained to grow a film having a thickness of about several tens to several tens of nanometers.

Examples of the reaction precursor used in the present invention include magnesium-containing organometallic biscyclopentadienyl magnesium [bis-cyclopentadienyl magnesium, (C ₅ H ₅ ) ₂ Mg], bismethylcyclopentadienyl magnesium [bis-methylcyclopentadienyl- Mg, (CH ₃ C ₅ H ₄ ) ₂ Mg], bisethylcyclopentadienyl magnesium [bis-ethylcyclopentadienyl-Mg, (C ₂ H ₅ C ₅ H ₄ ) ₂ Mg], bispentamethylcyclopentadienyl magnesium [bis-pentamethylcyclopentadienyl-Mg, {(CH ₃ ) ₅ C ₅ } ₂ Mg], magnesium acetate [Mg (OOCCH ₃ ) ₂ .2H ₂ O], magnesium acetate anhydride [Mg (OOCCH ₃ ) ₂ ], magnesium acetylaceto Nate [Mg (C ₅ H ₇ O ₂ ) ₂ .H ₂ O] and the like, cadmium-containing organic metals include diethyl cadmium and the like, manganese-containing organic metals such as biscyclo Pentadienyl manganese etc. are mentioned. Examples of the gallium-containing organic metal include trimethyl gallium (TMGa) and triethyl gallium (TEGa). Examples of the aluminum-containing organic metal include trimethyl aluminum (TMAl) and triethyl aluminum (TEAl). Examples of the indium-containing organic metal include trimethylindium (TMIn), and the titanium-containing organic metal includes tetrakis diethylamido titanium, Ti {N (C ₂ H _5). ) ₂ } ₄ ], Tetrakis dimethylamido titanium, Ti {N (CH ₃ ) ₂ } ₄ ], titanium tert-butoxide, Ti {O (tC ₄ H ₉ )} ₄ ], titanium ethoxide, Ti (OC ₂ H ₅ ) ₄ , titanium isopropoxide, Ti {O (iC ₃ H ₇ ) ₄ }], and the like.

The basic structure of the zinc oxide nanowires according to the present invention has a very distinct interface as a core-shell structure, as shown in FIG. 1 (a), and has a rectifier, a light emitting diode, and a photodetector as shown in FIG. Nanodevices such as devices, and HEMTs, spin devices, and the like shown in Fig. 1C. As shown in FIG. 1 (b), fabrication of nano-sized transistors, diodes, sensors, etc. through p-n junctions not only provides excellent stability and device efficiency, but also facilitates high integration. In addition, as shown in FIG. 1 (c), nanobands such as HEMT and spin devices may be manufactured by varying the band gap and the doped region.

As described above, the zinc oxide-based nanowires of the multi-wall structure manufactured according to the present invention can implement nanostructures satisfying a desired function as single nanowires, and thus are easy to integrate and fabricate core components of various nano devices. It can be advantageously used in the multi-function integrated nano device.

 The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited only to the following examples.

Example 1

Using argon as a carrier gas through separate lines, the reaction precursors, dimethylzinc (Zn (CH ₃ ) ₂ ) and O ₂ gases, were injected into the reactor at flow rates ranging from 0.1 to 10 sccm and 10 to 100 sccm, respectively. The materials were chemically reacted on the substrate to deposit and grow zinc oxide nanowires. The pressure in the reactor was maintained at 10 ⁻⁵ to 760 mmHg and the temperature at 400 to 900 ° C. during the growth of the nanowires over about 1 hour.

After completion of the deposition reaction, the result of measuring the cross section by scanning electron microscopy is shown in Fig. 2 (a). 2 (a), it can be seen that the diameter of the formed zinc oxide nanowires is about 10 nm, and the length is about 1 to 5 μm.

Subsequently, dimethylzinc, biscyclopentadienylmagnesium, (C ₅ H ₅ ) ₂ Mg] and O ₂ gases were separated via separate lines from 0.1 to 10 sccm, 1 to 50 sccm and 10 to 100, respectively. The reaction precursors were chemically reacted in the reactor for 10 minutes while maintaining the pressure at 5 torr and the temperature at 500 ° C., thereby coating zinc oxide on the zinc oxide nanowires. A zinc oxide magnesium oxide / zinc oxide nanowire having a multi-wall structure was prepared.

Example 2

Titanium oxide isopropoxide [Ti {O (iC ₃ H ₇ )} ₄ ] and O ₂ gas instead of dimethylzinc, biscyclopentadienylmagnesium and O ₂ gas as reaction precursors of the material to be coated on the zinc oxide nanowires Titanium oxide with a multi-wall structure coated with titanium oxide on zinc oxide nanowires in a similar manner to Example 1, except that was injected at a flow rate in the range of 1 to 50 sccm and 10 to 100 sccm, respectively. Zinc oxide nanowires were prepared.

Example 3

As a precursor of the material to be coated on the zinc oxide nanowires, TMGa and NH ₃ gases were injected at a flow rate in the range of 1 to 50 sccm and 100 to 2000 sccm, respectively, instead of dimethyl zinc, biscyclopentadienyl magnesium and O ₂ gas. A gallium nitride / zinc oxide nanowire having a multi-walled structure coated with gallium nitride on the zinc oxide nanowire was fabricated in a similar manner to Example 1, except that.

Scanning electron micrographs of the zinc oxide-based nanowires of each of the multiwall structures obtained above are shown in FIGS. 2 (b) to 2 (d). From FIG. 2, the zinc oxide nanowires are very thin, approximately 10 nm in diameter (FIG. 2 (a)), but when a heterogeneous material (magnesium oxide, titanium oxide and gallium nitride) is coated thereon (FIG. 2 (b) It can be seen that the zinc oxide-based nanowires having a multi-wall structure were successfully manufactured, as the diameters of 2 to 2 (d)) were about 20 to 50 nm thick.

Figure 3 (a) is a transmission electron micrograph of a multi-walled zinc oxide / gallium nitride nanowires prepared by coating gallium nitride on the zinc oxide nanowires, Figure 3 (b) is a multi-wall of Figure 3 (a) A transmission electron micrograph of a heterostructure in which a gallium nitride nanotube obtained by partially removing nanostructures of a structure and a multi-walled zinc oxide / gallium nitride is bonded is shown. From FIG. 3, on a zinc oxide nanowire having a diameter of about 10 nm. It can be seen that several nm thick gallium nitride was coated.

According to the present invention, zinc oxide nanowires having a multi-wall structure are manufactured in large quantities by appropriately controlling doping concentration and band gap by coating various materials such as metals, semiconductors, dielectrics, etc. in two or more layers on the zinc oxide nanowires. can do. Therefore, the basic structures of most electronic devices, optical devices, and sensors can be manufactured stably and efficiently within a single nanowire, and high integration can be easily implemented to implement multifunctional integrated nano devices and nano systems.

Claims (8)

On zinc oxide nanowires, transition metal materials, nitride semiconductors or dielectrics selected from magnesium (Mg), cadmium (Cd), manganese (Mn), zinc (Zn), cobalt (Co), alloys thereof and oxides thereof are heterogeneous Zinc oxide nanowires of multi-wall structure, coated as a material. delete The method of claim 1, A zinc oxide nanowire having a multi-wall structure, wherein the nitride semiconductor is GaN, AlN, InN, or an alloy thereof. The method of claim 1, A multi-walled zinc oxide nanowire, characterized in that the dielectric is titanium oxide (TiO ₂ ), titanium nitride (TiN), silicon oxide (SiO ₂ ) or barium titanium oxide (BaTiO ₃ ). Zinc-containing organometallic and oxygen-containing gases or oxygen-containing organics are injected into the reactor via separate lines, respectively, and oxidized on the substrate by chemical reaction at a pressure of 10 ^-5 to 760 mmHg and a temperature of 400 to 900 ° C. The multi-wall according to any one of claims 1 to 4, comprising depositing and growing a zinc nanowire, and then coating a heterogeneous material selected from transition metal materials, nitride semiconductors, and dielectrics on the grown zinc oxide nanowires. Method for producing zinc oxide nanowires having a structure. The method of claim 5, Coating methods include chemical vapor deposition including organometallic chemical vapor deposition, sputtering, thermal or electron beam evaporation, pulse laser deposition and vapor-phase transport processes. ) Is selected from. The method of claim 6, The coating method is characterized in that the organometallic chemical vapor deposition method. delete

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