JP4894180B2 - Nanowire having bonding of Ga and ZnS coated with silica film and method for producing the same - Google Patents

Description

  The present invention relates to a nanowire having a junction of Ga and ZnS coated with a silica film, which can be used in the field of electronic devices, and a method for producing the nanowire.

  One-dimensional nanostructures with junctions between different materials, ie heterojunctions, are of particular interest due to their potential applications in nanoelectronics and nanophotonics (SM Sze, 1981). Various functions can be realized by forming a junction in which two semiconductor nanowires or nanotubes are crossed in a cross shape. More sophisticated light emitting diodes (XF Duan et al., 2001) and complementary and diode logic devices can be clearly seen in nanotubes by crossing p-type and n-type nanowires or using lithography. It is predicted to be realized by defining the boundary between the p-type and n-type regions (XF Duan et al., 2001, Y. Huang et al., 2001, Y. Cui, 2001).

  However, compared to long-lasting advances in homogeneous nanowires and nanotubes, the formation of heterojunctions with one-dimensional nanostructures with well-defined interfaces is still inadequate and one-dimensional nanostructures There have been only a few reports on fabrication of heterojunctions in objects.

  Hu et al. Reported for the first time a catalytic vapor growth method for fabricating heterojunctions between carbon nanotubes and Si nanowires (JT Hu et al., 1999). In addition, Zhang et al. Developed a controlled solid-solid reaction method to fabricate heterojunctions between carbon nanotubes and silicon carbide or transition metal carbide. Others include reports of pn junctions on each carbon nanotube by chemical doping along the length direction or GaAs nanowhiskers (CW Zhou et al., 2000, K. Haraguchi et al., 1994) There are reports of sub-micron metal barcode rods by sequential electrochemical methods (NI Kovtyukhova et al., 2001).

  Recently, as a related study, multi-heterostructures with controlled composition of axial semiconductor nanowires, that is, superlattices, are based on controlled chemical vapor deposition (GaAs / GaP) (see Non-Patent Document 1). InAs / InP (see Non-Patent Document 2), Si / SiGe (see Non-Patent Document 3), and the like.

Research on low melting point metals confined in carbon nanotubes was first performed by Ajayan in 1993, and since then, this research has attracted attention. Similar phenomena have been observed in relation to In encapsulated in In ₂ O ₃ nanotubes.

  As described above, the bonding between the metal nanowire and the silicon nanowire becomes a metal-semiconductor bond, and is a material that is expected to be realized as a composite nanowire useful for downsizing electronic devices and optical devices.

M. S. Gudicksen et al., Nature, 2002, Vol.415, p.617 M. T. Bjoerk et al., Appl. Phys. Lett., 2002, Vol.80, p.1058 Y. Y. Wu et al., Nano Lett., 2002, Vol.2, p.83

  Recently, the present inventors have used a mixture of In and SiO as a raw material, and a metal (In) -semiconductor (Si) in which indium and silicon are in contact with each other by a simple method of thermally evaporating the mixture. It has been found that nanowire heterojunctions can be produced.

  In the present invention, a metal (Ga) -semiconductor (ZnS) nanowire heterojunction, which is a combination of a metal and a semiconductor different from the metal (In) -semiconductor (Si) nanowire heterojunction, is coated with a silica film. An object is to provide a nanowire having a junction of Ga and ZnS and a method for producing the nanowire.

In order to achieve the above object, a nanowire having a bond between Ga and ZnS coated with a silica film of the present invention is a nanowire formed by bonding a Ga nanowire and a ZnS nanowire, Is covered with a silica film.
The said structure WHEREIN: Preferably, a silica film is a silica nanotube which coat | covers the nanowire formed by joining Ga nanowire and ZnS nanowire, The film thickness is 4-8 nm.
Preferably, a plurality of junctions of Ga nanowires and ZnS nanowires are included in the silica nanotube. The diameter of the nanowire is preferably 150 to 250 nm, and its length is several μm to several tens of μm.
According to this configuration, since the tips of the metal Ga nanowire and the semiconductor ZnS nanowire are bonded to each other, a composite nanowire having a metal-semiconductor junction can be provided. In addition, since the composite nanowire is coated with a chemically stable silica film, the oxidation of the Ga nanowire and the ZnS nanowire is prevented, and the nanowire is chemically stable and hardly deteriorates in properties.

The method for producing a nanowire having a bond between Ga and ZnS coated with a silica film of the present invention is obtained by heat-treating a mixture of ZnS powder, Ga ₂ O ₃ powder and SiO powder in an inert gas stream. And a nanowire which is covered with a silica film and has a junction of Ga nanowire and ZnS nanowire inside.
In the above method, the weight ratio of the ZnS powder, the Ga ₂ O ₃ powder, and the SiO powder is preferably in the range of 0.6 to 1: 0.4 to 0.8: 0.8 to 1.2. The temperature of the heat treatment is preferably in the range of 1400-1500 ° C. The heat treatment time is preferably in the range of 1 to 2 hours. Moreover, argon gas is preferably used as the inert gas.
According to this method, composite nanowires composed of Ga nanowires and ZnS nanowires are obtained, the tips of these composite wires are bonded to each other, and the surface of the composite wire is chemically inert. A silica film is coated.
The composite nanowire has a nanowire diameter of 150 to 200 nm and a length of several μm to several tens of μm under the above-mentioned preferable conditions in a state where a silica film having a thickness of 4 to 8 nm is coated. Have dimensions.

According to the nanowire having a bond between Ga and ZnS coated with the silica film of the present invention, the nanowire composed of the Ga nanowire and the ZnS nanowire with the tips joined together is a chemically inert silica film. By covering in layers, deterioration of properties due to the high reactivity of the composite nanowire can be prevented. This nanowire has a junction of Ga and ZnS, and the junction is very sensitive to electron beam irradiation, so it can be used as an electronic device such as a switch driven by electron beam irradiation. is there.
According to the production method of the present invention, the nanowires, a mixture of ZnS powder and Ga ₂ O ₃ powder and SiO powder can be easily produced by heating in an inert gas stream.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of a heating furnace used for a nanowire having a bond between Ga and ZnS coated with a silica film of the present invention. A manufacturing method will be described using this apparatus as an example.
The heating furnace 1 includes a crucible 2, an induction heating cylindrical tube 3 that accommodates the crucible 2, a reaction tube 4 that accommodates the induction heating cylindrical tube 3, a high frequency induction heating coil 5 that is disposed outside the reaction tube 4, It is comprised including.
The reaction tube 4 is formed of a fused quartz tube or the like, and an upper flange 6 and a lower flange 7 that hold the reaction tube 4 in an airtight manner are provided at both ends of the reaction tube 4. The upper flange 6 and the lower flange 7 are respectively provided with inert gas inlets 8 and 9, and the lower flange 7 is provided with an inert gas outlet 10. In addition, the outside of the induction heating cylindrical tube 3 made of graphite or the like is covered with a carbon fiber 11 serving as a heat insulating material. Further, carbon tubes 12 and 13 for inactive gas inflow are disposed at the upper and lower portions of the induction heating cylindrical tube 3, and the inactive gas inflow carbon tube 13 at the lower side is an inflow port of the inactive gas. 9 is connected.
Further, the upper flange 6 is provided with a window portion 14 having a prism for measuring the temperature of the crucible 2. The temperature of the crucible 2 and the induction heating cylindrical tube 3 that accommodates the crucible 2 is measured from the window portion by a radiation thermometer such as a pyrometer (not shown).
Here, the heating furnace 1 is not limited to a vertical type and may be a horizontal type. The heating method is not limited to high-frequency induction heating, and may be a heating device by lamp heating that can heat the crucible 2.

Next, the manufacturing method of the present invention using the heating furnace 1 will be described.
As a first step, a mixture of raw materials 15 is prepared by mixing each powder of ZnS powder, Ga ₂ O ₃ powder and SiO (silicon monoxide) powder 15.
As a second step, the raw material 15 is put into a graphite crucible 2 and the crucible 2 is attached to the induction heating cylindrical tube 3.
As a third step, the pressure in the reaction tube 4 is reduced.
As a fourth step, after decompressing, an inert gas 16 such as argon gas is flowed from the upper and lower inert gas inlets 8 and 9.
As a fifth step, the temperature of the crucible 2 is rapidly heated to about 1400-1500 ° C. while flowing the inert gas 16.
As a sixth step, the heating temperature is maintained for a predetermined time.
As a seventh step, after heating for a predetermined time, the heating is stopped and the crucible 2 is rapidly cooled to room temperature. By this step, the raw material 15 in the crucible 2 evaporates, and the surface of the carbon fiber 11 serving as a heat insulating material outside the induction heating cylindrical tube 3 is densely covered with a synthetic material made of a light yellow substance. As will be described later, this composite is a nanowire having a bond of Ga and ZnS coated with a silica (silicon dioxide) film.
As an eighth step, a composite composed of the light yellow substance is recovered from the carbon fiber 11.

At this time, the weight ratio of the ZnS powder and Ga ₂ O ₃ powder and SiO (silicon monoxide) powder that is a raw material _{15, ZnS: Ga 2 O 3:} SiO = 0.6~1: 0.4~0. The range of 8: 0.8 to 1.2 is preferred.

The synthesis temperature of the crucible 2, that is, the temperature at which the crucible 5 is heated while flowing the inert gas 16 is preferably in the range of about 1400 to 1500 ° C. In this step, the reaction tube 4 is filled with yellow vapor. When the heating temperature is higher than 1500 ° C., Zn is more likely to be generated than ZnS, which is not preferable. Further, since the reaction tube 4 such as a quartz tube to be used is easily melted, it is not necessary to raise the temperature any more. Conversely, when the heating temperature is lower than 1400 ° C., it is not preferable because nanowires having a bond between Ga and ZnS coated with a silica film are hardly obtained.

  Further, the heating time at this time is preferably in the range of 1 to 2 hours, and since the reaction is completed in 2 hours, it is not necessary to spend more time. Conversely, a heating time of less than 1 hour is not preferable because the yield decreases.

The inert gas is preferably argon. The supply speed varies depending on the amount of the raw material 15 used and the size of the heating device 1. When the total amount of the raw material 15 is several g, the flow rates of the argon gas 16 supplied from the inert gas inlets 8 and 9 disposed at the upper and lower portions of the reaction tube 4 are 0.6 to 1. 2 liters (1000 cm ³ ) / min, preferably 1 to 1.5 liters / min.

  According to said manufacturing method, the nanowire which has junction of Ga and ZnS is obtained. Further, the surface of the composite wire is coated with a chemically inert silica film. As will be described later, the nanowire having a bond between Ga and ZnS coated with this silica film is, as an example, a bond between Ga and ZnS in a state where a silica film having a thickness of about 4 to 8 nm is coated. The diameter of the nanowire having a thickness of about 150 to 250 nm is about several μm to several tens of μm. By coating the surface of nanowires having a chemically active Ga / ZnS bond with a silica film, oxidation of these nanowires can be prevented and property deterioration can be prevented.

Next, a nanowire switch having a junction of Ga and ZnS coated with the silica film of the present invention will be described.
In the nanowire having a junction of Ga and ZnS coated with the silica film of the present invention, the junction of Ga and ZnS can be separated by heating Ga, which is a low melting point metal of the junction. Conversely, the separated junction can be joined again by movement of Ga. Therefore, this nanowire can be operated as a switch. For example, an electron beam can be used for this heating.

Next, based on an Example, this invention is demonstrated in detail.
ZnS (manufactured by Sigma-Aldrich, purity 99.99%) 0.8 g, Ga ₂ O ₃ (manufactured by Sigma-Aldrich, purity 99.99%) 0.5 g, SiO (manufactured by Sigma-Aldrich) 325 mesh) 1 g of a mixed powder of raw material 15 is put in a graphite crucible 2, and this crucible 2 is inserted into a graphite induction heating cylindrical tube 3 covered with a carbon fiber 11 of a heat insulating material. 1 was attached.

Then, after reducing the pressure in the reaction tube 2 of the heating furnace 1 to about 2 × 10 ⁻¹ Torr (26 Pa), an argon gas 16 was introduced into the reaction tube 2. The flow rate was 0.8 liter / minute from the upper inert gas inlet 8 and 1.2 liter / minute from the lower inert gas inlet 9.
Next, the graphite crucible 2 was rapidly heated to a temperature at which light yellow steam was generated, that is, a temperature of about 1400 to 1500 ° C. The temperature raising time at this time was about 20 minutes. And it hold | maintained at about 1400-1500 degreeC for 1.5 hours.
Finally, the heating furnace 1 was allowed to cool to room temperature. The carbon fiber 11 on the upper side of the induction heating cylindrical tube 4 was densely covered with a pale yellow composite.

2A is a diagram showing an X-ray diffraction pattern and FIG. 2B is a scanning electron microscope (SEM) image of the pale yellow compound obtained in Example 1. FIG. The vertical axis in FIG. 2A is the diffracted X-ray intensity (arbitrary scale), and the horizontal axis is the angle (°), that is, an angle corresponding to twice the incident angle θ of the X-ray to the atomic plane. X-ray diffraction measurement was performed using an X-ray diffractometer having a CuKα ray (RINT2200, manufactured by Rigaku Corporation), and SEM images (JSM-6700F) manufactured by JEOL Ltd. were used for observation of SEM images.
As is apparent from the X-ray diffraction pattern of FIG. 2 (a), the composition obtained in Example 1 is configured to contain a ZnS cubic crystal (JCPDS file: 05-0567). I understood. Moreover, it is estimated that the broad peak of 2 (theta) =-20-30 degree originates in the amorphous | non-crystalline substance in a composite.

  As is clear from the SEM image of FIG. 2B, the composite obtained in Example 1 was found to be a large amount of wire-like structures having a length of several μm to several tens of μm.

The structure of the wire-like structure obtained in the example was examined in more detail using a transmission electron microscope equipped with an energy dispersive X-ray analyzer.
FIGS. 3A to 3F are images showing transmission electron microscope images showing examples of the wire-like structure obtained in Example 1. FIG. Fig.3 (a) has shown the center part of the wire of a wire-shaped structure. As is clear from the measurement results of energy dispersive X-ray analysis described later, the wire-like structure obtained in Example 1 is a nanowire made of ZnS in a bright region within the contrast of light and darkness of a transmission electron microscope, and It was found that the nanowire made of metal Ga in the dark region was bonded to the nanowire, and the nanowire was covered with a silica film. This junction made of metal Ga and ZnS as a semiconductor is a junction that can also be called a metal-semiconductor junction or a heterojunction. Furthermore, it was found that the silica film had a nanotube shape covering the nanowire as a sheath. Hereinafter, the silica film is appropriately referred to as silica nanotube. And the diameter of this nanowire was about 150-250 nm, and the thickness of the silica nanotube was about 4-8 nm.

FIG.3 (b) is another structure of the wire-like structure obtained in Example 1, and has expanded the terminal part of the silica nanotube. Ga forms a bond with ZnS at the tube end so as to seal one end of the silica nanotube, and the ZnS nanowire occupies most of the voids in the silica nanotube.
FIG.3 (c) is another structure of the wire-shaped structure obtained in Example 1, Ga nanowire is located in the center part of a silica nanotube, and the left and right are joined with two ZnS nanowires. ing. In this case, it was found that two junctions were formed.
FIG. 3D shows another structure of the wire-like structure obtained in Example 1. The ZnS nanowire is located at the center of the silica nanotube, and its left and right are joined to two Ga nanowires. ing. This structure is a joint relationship in which the Ga nanowire and the ZnS nanowire in FIG. As described above, the wire-like structure shown in FIGS. 3C and 3D is a nanowire formed by bonding a Ga nanowire and a ZnS nanowire covered with a silica film, and the bonding is 2 It was found that the structure was formed individually.

  Although there are few examples, as indicated by arrows in FIGS. 3D and 3E, the ends of the Ga nanowires and the ends of the ZnS nanowires are not directly joined, and the silica nanotubes obtained in the examples are used. In some cases, a narrow hollow part was left in the inside.

  FIG. 3 (f) shows another structure of the wire-like structure obtained in Example 1, in which Ga nanowires and ZnS nanowires are periodically joined to each other in the length direction, and silica nanotubes This is an example in which two or more joints are formed.

FIG. 4 is a diagram showing measurement results by energy dispersive X-ray analysis of (a) Ga nanowire, (b) ZnS nanowire, and (c) silica nanotube, respectively, of the wire-like structure obtained in Example 1. It is. In the figure, the vertical axis represents the X-ray intensity (arbitrary scale), and the horizontal axis represents the X-ray energy (keV). The size of the electron beam used for X-ray analysis was about 2 nm.
As is clear from FIG. 4A, the nanowire in the dark region shown in FIG. 3 is made of Ga, and a small amount of Si and O signals show signals from the silica nanotubes that are the sheaths. .
As is clear from FIG. 4 (b), the nanowire in the bright region shown in FIG. 3 is composed of ZnS having a stoichiometric composition, and a small amount of Si and O signals are generated from the silica nanotube serving as the sheath. The signal is shown.
As is clear from FIG. 4C, the sheath of the nanowire is composed of Si and O, and the atomic ratio is Si: O = 1: about 1.9, which is silica. I understood that.
In FIG. 4, a copper (Cu) signal is observed, which originates from the copper grid used as a jig for attaching the sample.

Next, the production mechanism of nanowires having a bond between Ga and ZnS coated with the silica film obtained in Example 1 will be described.
FIG. 5 is a schematic diagram for explaining a generation mechanism of nanowires having a bond between Ga and ZnS coated with the silica film obtained in Example 1. FIG. When the ZnS powder, the Ga ₂ O ₃ powder, and the SiO powder as the raw material 15 are heated, silica nanotubes grow in the first stage, and then, Ga and ZnS nanowires grow in the silica nanotubes. Is estimated to occur. That is, in the production method of the present invention, the silica nanotube actually acts as a template, and is presumed to limit the one-dimensional growth of ZnS and Ga.

First, the growth of silica nanotubes will be described.
The temperature of the heating furnace 1 is increased, and at a high temperature exceeding about 1200 ° C., an oxidation-reduction reaction or disproportionation reaction of SiO to Si + SiO ₂ occurs, and the oxide assisted Si in different temperature distribution zones. Nanowires and various SiO ₂ nanowires (including silica nanowires) grow. In this route, as shown in FIG. 5A, the generated Si vapor is carried by an argon gas flow, and the silica nanotube 20 grows in a relatively low temperature range (about 1000 ° C.) of the heating furnace.

Next, when the temperature of the heating furnace 1 is further increased, the ZnS powder evaporates or sublimates at a relatively high rate to generate ZnS vapor. It is considered that Ga droplets or clusters having a boiling point of 2203 ° C. are generated during this period. The reaction in which Ga small droplets or clusters are generated is given by the following equations (1) and (2) when the heating furnace is held at about 1400-1500 ° C.
Ga ₂ O ₃ + 2C → Ga ₂ O + 2CO (1)
2Ga ₂ O ₃ + 4CO → 4Ga + C + 2CO ₂ (2)

  Both the ZnS vapor and the Ga small droplet 21 are carried by the argon gas flow and flow into the generated silica nanotube 20, and as a result, the ZnS vapor and the Ga small droplet 21 are deposited in the silica nanotube 20. For this reason, as shown in FIG. 5B, ZnS adsorbed on the surface of the Ga small droplets causes a ZnS-Ga solution 22 by diffusion and dissolution.

  As shown in FIG. 5 (c), when the heating furnace 1 is held at about 1400 to 1500 ° C. for a predetermined time, the ZnS vapor and Ga small droplet 21 are continuously generated, and ZnS in the silica nanotube 20 is formed. -The amount of Ga solution 22 increases.

Next, in the step of stopping the heating of the heating furnace 1 and rapidly cooling the crucible 2 to room temperature, as the crucible temperature 2 becomes lower, the ZnS—Ga solution 22 becomes supersaturated and ZnS is separated from the ZnS—Ga solution 22 or Precipitates. That is, the ZnS-Ga solution 22 undergoes phase separation due to thermal diffusion while accompanying a decrease in the free energy of the reaction system. Therefore, as shown in FIG. 5 (d), the result is that a ZnS phase 23 and a Ga phase 24 are generated in the silica nanotube 20.

  When the temperature of the heating furnace 1 is cooled to room temperature, the Ga phase 24 that is a liquid confined in the silica nanotube 20 is changed to Ga nanowires. Then, as shown in FIG. 3A and the like, a junction made of Ga nanowires and ZnS nanowires is formed inside the silica nanotubes 20.

In addition, when Ga nanowires and ZnS nanowires do not join due to the volume reduction of Ga in the silica nanotubes 20 due to this cooling, the presence of Ga and ZnS nanowires in the voids, that is, the silica nanotubes It is presumed that a hollow portion that does not occur is generated (see the portions indicated by arrows in FIGS. 3D and 3E).
The generation mechanism of nanowires having a bond between Ga and ZnS coated with the silica film obtained in Example 1 is a method of synthesizing silicon carbide or metal carbide nanowires (twigs) restricted by carbon nanotubes. In the example, the silica nanotubes ultimately form a nanowire sheath with a Ga and ZnS junction. In the above generation mechanism, process factors such as the wetness of ZnS with Ga droplets, the size and distribution of Ga droplets in the silica nanotubes, the flow rate of the carrier gas and the thermal fluctuations are the reasons for the bonding of Ga and ZnS. It can be presumed that it plays an important role in the formation of nanowires having selenium.

Next, a nanowire switch having a junction of Ga and ZnS coated with the silica film manufactured in Example 1 will be described.
FIG. 6 is an image showing a transmission electron microscope image when a nanowire having a junction of Ga and ZnS coated with the silica film of Example 2 is irradiated with an electron beam. Before irradiation of the beam, (b) when the electron beam is irradiated, (c) when the electron beam is separated from the junction, and (d) when the electron beam is sufficiently moved away from the junction.
As is clear from FIG. 6A, the Ga and ZnS nanowires covered with the silica film are bonded before the electron beam irradiation.

Next, when an electron beam having a size of about 200 nm is irradiated to a nanowire having a Ga / ZnS junction coated with a silica film, the junction is cut off, as indicated by an arrow in FIG. Ga in the junction of Ga and ZnS moves into the gap, and the junction becomes a void of a silica nanotube made of only SiO ₂ .
In this case, by irradiating a junction made of nanowires of Ga and ZnS with an electron beam, the temperature of the junction increases, and Ga having a low melting point of 29.8 ° C. starts to melt. At the same time, due to the very low pressure of about 1 × 10 ⁻⁵ Pa in a transmission electron microscope containing nanowires having a Ga and ZnS junction coated with a silica film, the heat of the Ga nanowires Expansion occurs. It is estimated that due to this thermal expansion, the Ga nanowire moves in the silica nanotube, and the bond is cut off.

  Next, the electron beam starts to move away from the junction along the Ga nanowire (see FIG. 6C), and when the electron beam is sufficiently moved away from the junction, as shown in FIG. Ga and ZnS nanowires are joined. Thus, when an electron beam leaves | separates from joining, Ga nanowire solidifies again from a liquid to solid, Ga nanowire comes to join again with ZnS nanowire.

  As a result, it was found that, in the bonding of nanowires having a bond of Ga and ZnS coated with a silica film, the electron beam is irradiated to the bond to move the Ga and operate as a switch.

  According to the present invention, it is possible to obtain a nanowire composed of a Ga nanowire and a ZnS nanowire that are coated with a chemically inert silica film and the tips of which are joined together. Applications to electronic and optical devices that act as switches when irradiated are expected.

It is typical sectional drawing of the heating furnace used for the nanowire which has joining of Ga and ZnS coat | covered with the silica film of this invention. It is a figure where (a) shows an X-ray diffraction pattern and (b) shows a scanning electron microscope (SEM) image of the pale yellow compound obtained in Example 1. (A)-(f) is an image which shows the transmission electron microscope image which shows the example of the wire-shaped structure obtained in Example 1. FIG. It is a figure which shows the measurement result by the energy dispersive X-ray analysis in (a) Ga nanowire, (b) ZnS nanowire, and (c) silica nanotube of the wire-shaped structure obtained in Example 1, respectively. It is a schematic diagram explaining the production | generation mechanism of the nanowire which has joining of Ga and ZnS which were coat | covered with the silica film obtained in Example 1. FIG. It is an image which shows the transmission electron microscope image when the electron beam is irradiated to the nanowire which has the junction of Ga and ZnS coated with the silica film of Example 2, and (a) is irradiation of an electron beam, respectively. Previously, (b) during electron beam irradiation, (c) when the electron beam is separated from the junction, and (d) when the electron beam is sufficiently away from the junction.

Explanation of symbols

1: heating furnace 2: crucible 3: induction heating cylindrical tube 4: reaction tube 5: coil for high frequency induction heating 6: upper flange 7: lower flange 8, 9: inlet of inert gas 10: outlet of inert gas 11: carbon fiber 12, 13: carbon pipe 14: window 15: raw material 16: inert gas (argon gas)
20: Silica nanotube 21: ZnS vapor and Ga droplet 22: ZnS-Ga solution 23: ZnS phase 24: Ga phase

Claims (9)

  A nanowire formed by bonding a Ga nanowire and a ZnS nanowire, wherein the nanowire is coated with a silica film, and the bonding of Ga and ZnS coated with a silica film is performed. Having nanowires.   The said silica film is a silica nanotube which coat | covers the nanowire formed by the said Ga nanowire and ZnS nanowire joining, The film thickness is 4-8 nm, It is characterized by the above-mentioned. A nanowire having a junction of Ga and ZnS coated with a silica film.   3. The silica nanotube according to claim 1 or 2, wherein the silica nanotube includes a plurality of junctions between the Ga nanowire and the ZnS nanowire. Nanowire with bonding.   The Ga and ZnS coated with the silica film according to claim 1, wherein the nanowire has a diameter of 150 to 250 nm and a length of several nanometers to several tens of micrometers. Nanowires with junctions. By heat-treating a mixture of ZnS powder, Ga ₂ O ₃ powder and SiO powder in an inert gas stream,
A method for producing a nanowire having a bond between Ga and ZnS coated with a silica film, characterized in that the nanowire is coated with a silica film and having a bond between Ga nanowire and ZnS nanowire inside. . The weight ratio of the ZnS powder, the Ga ₂ O ₃ powder, and the SiO powder is in the range of 0.6-1: 0.4-0.8: 0.8-1.2, Item 6. A method for producing nanowires having a bond between Ga and ZnS coated with the silica film according to Item 5.   The method for producing a nanowire having a bond between Ga and ZnS coated with a silica film according to claim 5, wherein the temperature of the heat treatment is set in a range of 1400 to 1500 ° C.   The said heat processing time is made into the range of 1-2 hours, The manufacturing method of the nanowire which has joining of Ga and ZnS which were coat | covered with the silica film of Claim 5 characterized by the above-mentioned.   The method for producing a nanowire having a bond between Ga and ZnS coated with a silica film according to claim 5, wherein argon gas is used as the inert gas.