KR20070119939A - 3d structural nano devices having zinc oxide type nano wires and devices using it - Google Patents

Abstract

A nano device with a three-dimensional structure is provided to have a three dimensional structure of conductive thin film/zinc oxide-based nanowires/conductive thin film applicable to good photoelectronic devices and gas-detecting devices. A nano device with a three-dimensional structure includes: a first conductive thin film(1) formed on a substrate(4); many zinc oxide-based nanowires(3) which are grown on the first conductive thin film in a columnar form; and a second conductive thin film(2) which is formed on the ends of the nanowires so as to face the first conductive thin film. The many nanowires are connected in parallel between the first and second conductive thin films.

Description

3D structural nano devices having zinc oxide type nano wires and devices using it}

1 is n ⁺ according to the invention is also a process diagram schematically showing a manufacturing process of a nano device with a three-dimensional structure of the semiconductor thin film of the type and structure Fig Oh semiconductor thin film / oxide linkage type nano / n ⁺ .

Figures 2a and 2b are n ⁺ in accordance with the present invention a scanning electron micrograph of a nano device with a three-dimensional structure of a type semiconductor thin film-type of the semiconductor thin film / zinc oxide based nanowire / n ⁺ (SEM: Scanning Electron Microscopy) 2A is a scanning electron micrograph of a nano device having a three-dimensional structure of n ⁺ -type semiconductor thin film / zinc oxide nanowire / n ⁺ -type semiconductor thin film at a 45 degree angle, and FIG. Scanning electron micrographs sequentially observe the bonding process of n ⁺ -type semiconductor thin films on interconnected nanowires.

N ⁺ 3 is in accordance with the present invention is a current graph showing the change in UV detection characteristics of the nano-elements having a three-dimensional structure of a type of the semiconductor thin-type semiconductor thin film / zinc oxide based nanowire / n ^+.

<Explanation of symbols on main parts of the drawings>

1-first conductive thin film 2-second conductive thin film

3-Zinc Oxide Nanowire 4-Substrate

5-electrode

The present invention relates to a nano device having a three-dimensional structure formed by combining a conductive thin film having excellent electrical conductivity at both ends of a plurality of nanowires, and an apparatus using the same. In particular, the present invention relates to a device having a three-dimensional structure in which nanowires vertically arranged on a conductive thin film used as an electrode and a conductive thin film used as an electrode are combined on the formed nanowire.

Zinc oxide, which is known to have a wide band gap energy of 3.3 eV and a large exciton bonding energy of 60 meV at room temperature, is a material that is expected to be used as a light emitting device and a light detecting device having a wavelength of 375 to 420 nm. In addition, since the electrical properties of zinc oxide change when oxygen is adsorbed or desorbed on the grain boundaries of zinc oxide, it is possible to fabricate a gas detection device using zinc oxide. Recently, aluminum (Al) and gallium (Ga) are doped with zinc oxide to develop transparent electrodes with excellent electrical conductivity and applied to liquid crystal display (LCD) devices and plasma display panels (PDP). Research is underway. However, when the existing zinc oxide thin film structure is used as the active material of the optoelectronic device or the gas detection device, the efficiency is lower than that when the nanowire structure having excellent crystallographic properties is used.

Recently, in order to apply excellent crystallographic, quantum mechanical, and size characteristics of nanowires to a device, a technology of synthesizing zinc oxide (ZnO) nanowires and gallium nitride (GaN) nanowires and dispersing them on a substrate Is using. However, the existing technology of dispersing nanowires and forming electrodes uses one nanowire as an active material for detection, which is caused by external environmental changes such as light energy or chemical reactions with atmospheric substances on the surface of nanowires. The electrical signal change inside the nanowire is very small. In addition, in order to device nanowires, since nanoscale one-dimensional nanostructures must be controlled respectively, there is a limit to mass production using existing semiconductor technology.

Accordingly, an object of the present invention is to use a sputtering method and a metal organic chemical vapor deposition method used in a conventional semiconductor process, and a conductive thin film / oxidation which can be applied to excellent optoelectronic devices and gas detection devices. An object of the present invention is to provide a nano device having a three-dimensional structure of a zinc-based nanowire / conductive thin film.

Another object of the present invention is to compare the surface of each zinc oxide-based nanowires connected in parallel to the external environment in order to effectively convert chemical changes of light energy, gas, etc. into electrical signals as compared to the device structure using the conventional nanowires. It is to provide a nano-device having a three-dimensional structure of the conductive thin film / zinc oxide nanowire / conductive thin film that is an exposed structure.

In order to achieve the above object, the present invention synthesizes the first conductive thin film 1 on the substrate 4 by the sputtering method or organometallic chemical vapor deposition method, and using the organometallic chemical vapor deposition method on the zinc oxide nanowires (3) was grown, and the second conductive thin film (2) was synthesized by sputtering or organometallic chemical vapor deposition on the zinc oxide nanowire (3) to form the first conductive thin film (1) / zinc oxide nanowire. (3) / Second conductive thin film (2) A nano device having a three-dimensional structure is provided.

A first conductive thin film 1 formed on the substrate; A plurality of zinc oxide-based nanowires 3 grown in columnar shape on the first conductive thin film; And a second conductive thin film 2 formed at an end of the zinc oxide nanowire to face the first conductive thin film. It provides a nano device having a three-dimensional structure consisting of.

The plurality of zinc oxide nanowires 3 are connected in parallel between the first and second conductive thin films 1 and 2, and the electrical properties of the zinc oxide change when oxygen is adsorbed or desorbed at the grain boundaries of the zinc oxide. In order to take advantage of the properties, it is preferred that the columnar portions, except for the ends combined with the first and second conductive thin films 1, 2, are formed to be completely exposed to the atmosphere.

It is preferable that the 1st and 2nd conductive thin films 1 and 2 are n ⁺ -type semiconductor thin films synthesize | combined by the sputtering method or the organometallic chemical vapor deposition method. More preferably, the formed first and second conductive thin films 1 and 2 are doped with a group III-material when synthesized by the sputtering method, and crystallized under high supersaturation conditions when synthesized by the organometallic chemical vapor deposition method. It is synthesized into this connected polycrystalline structure, so as to have high electrical conductivity due to defects present in grain boundaries.

In addition, by using a nano-element having a three-dimensional structure, the nano-element having a three-dimensional structure of the first conductive thin film (1) / zinc oxide-based nanowire (3) / second conductive thin film (2); Electrodes 5 attached to the first and second conductive thin films; A circuit connected to the electrode and having a current change measuring device; It provides a detection device, characterized in that consisting of.

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

The nano device having a three-dimensional structure of the first conductive thin film (1) / zinc oxide nanowire (2) / second conductive thin film (3) according to the present invention has a growth temperature using a sputtering method or an organometallic chemical vapor deposition method. Synthesis of the first conductive thin film 1 on the substrate 4 with an n ⁺ -type semiconductor having excellent electrical conductivity at a high supersaturation condition of 250-350 ° C., and using an organometallic chemical vapor deposition method thereon. To grow zinc oxide nanowires 3 under low supersaturaion conditions with a growth temperature of 550-700 ° C. and a growth pressure of 1-3 torr. The second conductive thin film 2 is synthesized by an n ⁺ -type semiconductor having excellent electrical conductivity under high supersaturation conditions by sputtering or organometallic chemical vapor deposition on the zinc oxide-based nanowire 3 to obtain a first conductivity. A nano device having a three-dimensional structure of a thin film (1) / zinc oxide nanowire (3) / second conductive thin film (2) is manufactured.

According to the present invention, the two conductive thin films 1 and 3 connecting both ends of the zinc oxide nanowire 3 in parallel are n ⁺ -type having excellent electrical conductivity synthesized by sputtering or organometallic chemical vapor deposition. It is a semiconductor thin film. When the n ⁺ -type semiconductor thin film is sputtered, the AlZnO, GaZnO and InSnO thin films are synthesized using AlZnO, GaZnO, and InSbO targets doped with group III-materials, and zinc precursors are used when organometallic chemical vapor deposition is used. Diethylzinc (Zn (C ₂ H ₅ ) ₂₎ , diethyl zinc (Zn (CH ₃ ) ₂ ), and the like, and O ₂ , N ₂ O, NO ₂ as an oxygen-containing gas for oxidizing zinc. Etc. can be used.

The n ⁺ -type semiconductor thin film having excellent electrical properties synthesized on the zinc oxide nanowire 3 is a polycrystalline thin film in which crystal grains synthesized at the ends of the plurality of zinc oxide nanowires 3 are connected. The zinc oxide nanowires 3 can be used as nuclei for crystal growth, and raw materials supplied at high supersaturation conditions form grains on each zinc oxide nanowire. Such a polycrystalline thin film may have high electrical conductivity due to defects in grain boundaries, or may be doped with a III-group material to form an n ⁺ -type semiconductor thin film having excellent electrical conductivity. Therefore, the first conductive thin film (1) / zinc oxide-based nanowires (3) / second conductive thin film (2) having n ⁺ -type semiconductor thin film structures having excellent electrical conductivity at both ends of the zinc oxide nanowires (3) The electrical conductivity of nanoparticles having a three-dimensional structure is determined by the change in electrical resistance of the zinc oxide nanowires (3). In addition, in the case of the second conductive thin film 2 synthesized on the zinc oxide nanowire 3, the material constituting the thin film does not deposit on the surface of the zinc oxide nanowire 3 or the like. It is synthesized at the end of) so that the device can be realized by using the surface characteristics of zinc oxide completely exposed to the atmosphere.

Since zinc oxide nanowires (3) have excellent crystallinity of single crystals, the concentration of electrons due to crystal defects is lower than 10 ⁶ cm and high electrical resistance, so that they are exposed to light energy such as ultraviolet rays or zinc oxide-based nanowires. The electrical conductivity changes greatly with the concentration change of electrons or holes due to the chemical reaction on the surface of the route 3. In addition, the diameter of the zinc oxide nanowires 3 can be controlled to 30 to 80 nm by the synthesis temperature of the zinc oxide nanowires 3, and the smaller and longer the diameter of the zinc oxide nanowires 3 is. It can be confirmed that the ultraviolet ray detection and the atmosphere gas detection performance are excellent.

The zinc oxide-based nanowire 3 can change the characteristics of the zinc oxide surface by using a post-heat treatment process in an atmosphere of hydrogen gas at atmospheric pressure, thereby preventing a change in electrical conductivity caused by the atmosphere gas. At the same time, the surface properties can be controlled to facilitate the adsorption of organic materials through a post heat treatment process.

The first conductive thin film (1) / zinc oxide-based nanowire (3) / second conductive thin film (2) of the manufactured first electrode and the second conductive thin film (1, 2) of the nano device having a three-dimensional structure, respectively, 5) by attaching a voltage and measuring a change in the amount of current flowing through the zinc oxide nanowire 3, a detection device using a new type of zinc oxide nanowire 3 can be fabricated.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only for illustrating the present invention and do not limit the present invention.

Example 1: Fabrication of a device having a three-dimensional structure of a conductive thin film / zinc oxide nanowire / conductive thin film

In order to manufacture the structure of FIG. 1, an AlZnO thin film having excellent electrical conductivity is deposited by sputtering a zinc oxide target doped with 3 wt% aluminum at room temperature, and an organometallic chemical vapor phase capable of supplying a reaction gas through a shower nozzle. Diethyl zinc and oxygen were supplied to the evaporator at 5 ~ 33㎛ol / min, 20 ~ 25 sccm, respectively, and maintained vertically on the deposited AlZnO thin film at a growth temperature of 500 ~ 650 ° C and a growth pressure of 1 ~ 3 torr. The zinc oxide-based conductive thin film / nanowire / conductive thin film is grown by growing an arrayed zinc oxide nanowire, and then sputtering a zinc oxide target doped with 3 wt% aluminum on the nanowire at room temperature to deposit a polycrystalline AlZnO thin film having excellent electrical conductivity. A device having a three-dimensional structure of is manufactured.

A device having a three-dimensional structure of the synthesized zinc oxide-based conductive thin film / nanowire / conductive thin film is shown in FIG. 2A. The diameter and length of the nanowires were observed at 50nm and 700nm, respectively.

In addition, in order to observe the shape of the thin film synthesized on the nanowires, the results of observing the shape of the thin film synthesized on the nanowires according to the sputtering time with a scanning electron microscope is shown in Figure 2b.

Example 2 Fabrication of Ultraviolet Detection Device Using Device Having 3D Structure of Conductive Thin Film / Zinc Oxide Nanowire / Conductive Thin Film

The device structure of FIG. 1 is manufactured by forming electrodes on conductive thin films connected to both ends of a zinc oxide nanowire having a three-dimensional structure of a conductive thin film / zinc oxide nanowire / conductive thin film. When irradiating UV light having a wavelength of 350 to 370 nm having a wavelength shorter than 377 nm corresponding to the band gap energy of the zinc oxide nanowire to the nano device having the conductive thin film / zinc oxide nanowire / conductive thin film three-dimensional structure, As shown, it can be observed that the amount of current flowing through the zinc oxide-based nanowire increases three times as compared to before irradiation with ultraviolet rays, and the current amount rapidly increases within one second after irradiation with ultraviolet rays.

According to the present invention, a nano device having a first conductive thin film / zinc oxide-based nanowire / second conductive thin film three-dimensional structure can be manufactured using a plurality of zinc oxide-based nanowires only using a conventional thin film deposition technique. In addition, since the surface of many zinc oxide nanowires are all exposed to the atmosphere, it is possible to apply them to the development of various detection devices using zinc oxide nanowires.

Claims (7)

A first conductive thin film formed on the substrate; A plurality of zinc oxide based nanowires grown in columnar shape on the first conductive thin film; And A second conductive thin film formed at an end of the nanowire so as to face the first conductive thin film; Nano device having a three-dimensional structure consisting of. The method of claim 1, A plurality of nanowires, the nano device having a three-dimensional structure, characterized in that connected in parallel between the first and second conductive thin film. The method of claim 2, Many nanowires are exposed to the atmosphere, except for the ends combined with the first and second conductive thin films, in order to take advantage of the property that the electrical properties of zinc oxide change when oxygen is adsorbed or desorbed at the grain boundaries of zinc oxide. Nano device having a three-dimensional structure, characterized in that formed to be. The method of claim 1, The first and second conductive thin films are nanodevices having a three-dimensional structure, characterized in that the n ⁺ -type semiconductor thin film synthesized by any one selected from a sputtering method and an organometallic chemical vapor deposition method. The method of claim 4, wherein The first and second conductive thin films have a three-dimensional structure, characterized in that when synthesized by the sputtering method doped the group III-material has a high electrical conductivity. The method of claim 4, wherein When the first and second conductive thin films are synthesized by an organometallic chemical vapor deposition method, the first and second conductive thin films are synthesized in a polycrystalline structure in which crystal grains are connected under high supersaturation conditions, and thus have high electrical conductivity due to defects present at grain boundaries. Nano device having a three-dimensional structure characterized in. Nano device having a three-dimensional structure of any one of claims 1 to 6; Electrodes attached to the first and second conductive thin films; A circuit connected to the electrode and having a current change measuring device; Detection apparatus characterized in that consisting of.

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