TW201717415A - Oxide semiconductor secondary battery and method of manufacturing same - Google Patents

Abstract

The present invention provides an oxide semiconductor secondary battery and a method of manufacturing the same. The oxide semiconductor secondary battery of the present embodiment includes a first electrode (14), an n-type metal oxide semiconductor layer (16) formed over the first electrode (14), and a charging layer (18). Formed above the n-type metal oxide semiconductor layer (16) and composed of a substance containing an n-type metal oxide semiconductor and an insulating substance; and a p-type metal oxide semiconductor layer (20) formed on the charging layer ( 18); and a second electrode (22) formed over the p-type metal oxide semiconductor layer (20). The n-type metal oxide semiconductor layer (16) is titanium dioxide containing an anatase structure or an amorphous structure.

Description

Oxide semiconductor secondary battery and method of manufacturing same

The present invention relates to an oxide semiconductor secondary battery and a method of manufacturing the same.

A battery (hereinafter referred to as a quantum battery) which is formed by a change in light excitation structure of a metal oxide caused by ultraviolet irradiation has been proposed (Patent Document 1). The secondary battery disclosed in Patent Document 1 is of an all-solid type, and a chemical reaction is not used during charge and discharge, which is safe. Moreover, this secondary battery is expected to be a technology that overrides a lithium ion battery in terms of output density and power density. The secondary battery of Patent Document 1 has a structure in which a first electrode, an n-type metal oxide semiconductor layer, a charge layer, a p-type semiconductor layer, and a second electrode are laminated on a substrate.

[Previous Technical Literature]

[Patent Document]

Patent Document 1: International Publication No. 2012/046325.

In Patent Document 1, as the n-type metal oxide semiconductor layer, titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), or zinc oxide (ZnO) is used. As the first electrode, a metal electrode such as a silver (Ag) alloy film containing aluminum (Al) is used. Patent Document 1 discloses the formation of a metal electrode by electroplating or electroless plating. Further, there are described metals used for electroplating, and generally copper, copper alloy, nickel, aluminum, silver, gold, zinc or tin can be used.

In quantum batteries, it has been desired to develop a secondary battery having more excellent characteristics.

The present invention has been developed in view of the above problems, and an object thereof is to provide an oxide semiconductor secondary battery having excellent characteristics and a method of manufacturing the same.

An oxide semiconductor secondary battery according to an aspect of the present invention includes: a first electrode; an n-type metal oxide semiconductor layer formed over the first electrode; and a charging layer formed on the n-type metal Above the oxide semiconductor layer, and composed of a substance containing an n-type metal oxide semiconductor and an insulating substance; and a p-type metal oxide semiconductor layer formed on the foregoing charge a second electrode formed above the p-type metal oxide semiconductor layer; the n-type metal oxide semiconductor layer containing an anatase structure or an amorphous structure Titanium dioxide.

In the above oxide semiconductor secondary battery, it is preferable that the n-type metal oxide semiconductor layer is titanium oxide having the anatase structure.

In the above oxide semiconductor secondary battery, it is preferable that the outermost layer of the first electrode is formed of a chrome film, and the n-type metal oxide semiconductor layer is in contact with the chromium film.

In the above oxide semiconductor secondary battery, it is preferable that the outermost layer of the first electrode is formed of a titanium film, and the n-type metal oxide semiconductor layer is in contact with the titanium film.

In the above oxide semiconductor secondary battery, it is preferable that an anatase is obtained in an X-ray diffraction pattern obtained by X-ray diffraction measurement of the θ-2 θ method on the n-type metal oxide semiconductor layer. The diffraction intensity of the ore (101) plane becomes higher than the diffraction intensity of the rutile (110) plane.

A method of producing an oxide semiconductor secondary battery according to an aspect of the present invention includes the steps of: forming a first electrode; and forming an n-type metal oxide semiconductor layer made of titanium oxide above the first electrode Formed on top of the n-type metal oxide semiconductor layer a step of forming a charging layer of a substance having an n-type metal oxide semiconductor and an insulating substance; a step of forming a p-type metal oxide semiconductor layer over the charging layer; and above the p-type metal oxide semiconductor layer a step of forming a second electrode; the n-type metal oxide semiconductor layer contains titanium dioxide having an anatase structure or an amorphous structure.

In the above manufacturing method, it is preferable that the n-type metal oxide semiconductor layer is titanium oxide having the anatase structure.

In the above manufacturing method, it is preferable that the outermost layer of the first electrode is formed of a chromium film, and the n-type metal oxide semiconductor layer is in contact with the chromium film.

In the above manufacturing method, it is preferable that the outermost layer of the first electrode is formed of a titanium film, and the n-type metal oxide semiconductor layer is in contact with the titanium film.

In the above-described production method, it is preferable that the anatase-structured titanium oxide is formed by heating the n-type metal oxide semiconductor layer after forming the n-type metal oxide semiconductor layer.

In the above manufacturing method, it is preferable to obtain an X-ray diffraction measurement by the θ-2 θ method on the n-type metal oxide semiconductor layer. In the X-ray diffraction pattern, the diffraction intensity of the anatase (101) plane becomes higher than the diffraction intensity of the rutile (110) plane.

According to the present invention, an oxide semiconductor secondary battery having excellent characteristics and a method of manufacturing the same can be provided.

10‧‧‧Oxide semiconductor secondary battery

12‧‧‧Substrate

14‧‧‧First electrode

14a‧‧‧Chromium film

14b‧‧‧Palladium membrane

14c‧‧‧chrome film

16‧‧‧n type metal oxide semiconductor layer

18‧‧‧Charging layer

20‧‧‧p-type metal oxide semiconductor layer

22‧‧‧second electrode

FIG. 1 is a schematic view showing a cross-sectional structure of an oxide semiconductor secondary battery 10.

Fig. 2 is a schematic view showing the composition of a sample analyzed by X-ray diffraction.

Fig. 3 is an X-ray diffraction pattern showing a difference in crystal structure of titanium dioxide caused by a base film.

Fig. 4 is a view showing an X-ray diffraction pattern in the case where a substrate is used as a chromium film.

Fig. 5 shows an X-ray diffraction pattern in the case where the substrate is used as a palladium film.

Fig. 6 is a view showing an X-ray diffraction pattern in the case where a substrate is used as a titanium film.

Fig. 7 is a flow chart showing a method of manufacturing an oxide semiconductor secondary battery.

Fig. 8 is a flow chart showing the details of the steps of forming the charging layer.

Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. The following description shows preferred embodiments of the present invention, and the technical scope of the present invention is not limited to the following embodiments.

The present invention relates to a quantum battery (hereinafter referred to as "oxide semiconductor secondary battery") which is produced based on a new charging principle, and a method of manufacturing an oxide semiconductor secondary battery. The oxide semiconductor secondary battery is a secondary battery that can be charged and discharged.

Specifically, in the oxide semiconductor secondary battery, the charging layer is irradiated with ultraviolet rays to change the conductivity of the charging layer.

(Battery structure)

Fig. 1 is a schematic view showing a cross-sectional structure of an oxide semiconductor secondary battery of the present embodiment.

In FIG. 1, an oxide semiconductor secondary battery 10 has a first electrode 14 which is electrically laminated on a substrate 12, an n-type metal oxide semiconductor layer 16, a charging layer 18 for charging energy, and p-type metal oxide. The layered structure of the material semiconductor layer 20 and the second electrode 22.

The material of the substrate 12 may be either an insulating material or a conductive material. For example, as the material of the substrate 12, a glass substrate or A resin sheet of a polymer film or a metal foil sheet.

The first electrode 14 and the second electrode 22 are formed of a laminated film of chromium (Cr) and palladium (Pd) or an aluminum (Al) film to reduce the electric resistance to form a conductive film. For example, as the first electrode 14, a metal electrode containing chromium (Cr), titanium (Ti) or the like can be used. Alternatively, an alloy containing chromium or titanium as a main component may be used. The first electrode 14 may also have a laminated structure in which different metals are laminated. Further, as the second electrode system, a metal electrode such as chromium (Cr) or copper (Cu) can be used. As another metal electrode system, a silver (Ag) alloy film containing aluminum (Al) or the like is provided. Examples of the method for forming the film include a vapor phase film formation method such as sputtering, ion plating, electron beam evaporation, vacuum vapor deposition, and chemical vapor deposition. Further, the metal electrode can be formed by an electroplating method, an electroless plating method, or the like. As the metal used for the plating, copper, copper alloy, nickel, aluminum, silver, gold, zinc or tin can be generally used.

As a material of the n-type metal oxide semiconductor layer 16, for example, titanium oxide (TiO ₂ ) can be used. Further, in the present embodiment, an anatase type or an amorphous type of titanium dioxide is used in the n-type metal oxide semiconductor layer 16. Further, a preferable combination of materials regarding the first electrode 14 and the n-type metal oxide semiconductor layer 16 will be described later.

As the material of the charging layer 18, an n-type metal oxide semiconductor of fine particles can be used. The n-type metal oxide semiconductor changes its light-excited structure with ultraviolet light irradiation, and becomes a layer having a charging function. Charging layer The 18 series is composed of a substance containing an n-type metal oxide semiconductor and an insulating substance. As the n-type metal oxide semiconductor material which can be used in the charging layer 18, titanium oxide, tin oxide, or zinc oxide is preferable. It is possible to use a material in which any two of titanium dioxide, tin oxide, and zinc oxide are combined, or a material in which three are combined.

The p-type metal oxide semiconductor layer 20 formed on the charging layer 18 is provided to prevent electrons from being injected into the charging layer 18 from the upper second electrode 22. As the material of the p-type metal oxide semiconductor layer 20, nickel oxide (NiO), copper aluminum oxide (CuAlO ₂ ), or the like can be used.

Further, the order of lamination on the substrate 12 in the present embodiment may be reversed. In other words, the first electrode 14 may be the uppermost layer and the second electrode 22 may be the lowermost layered structure. Next, an example of the actual trial is shown.

(Structure of Charging Layer 18)

The charging layer 18 is a mixture of an insulating material and an n-type metal oxide semiconductor. Hereinafter, the charging layer 18 will be described in detail. The charging layer 18 uses silicon oil as a material of an insulating material. Further, titanium dioxide is used as a material of the n-type metal oxide semiconductor.

Titanium dioxide, tin oxide, and zinc oxide are used as the material of the n-type metal oxide semiconductor used in the charging layer 18. An n-type metal oxide semiconductor is derived from the decomposition of an aliphatic acid salt of such a metal in a manufacturing step to make. Therefore, as the aliphatic acid salt of the metal, those which can be decomposed or burned by irradiation with ultraviolet rays in an oxidizing atmosphere or by firing, and which are changed into a metal oxide can be used.

Further, based on the fact that it is easily decomposed or burned by heating, the solvent solubility is high, the composition of the film after decomposition or combustion is dense, easy to handle, inexpensive, and easy to synthesize with a metal, the aliphatic acid salt is more preferable. It is a salt of an aliphatic acid and a metal compound.

Next, the materials of the first electrode 14 and the n-type metal oxide semiconductor layer 16 and combinations thereof will be described in detail. The inventors of the present application discovered the materials of the first electrode 14 and the n-type metal oxide semiconductor layer 16 which exhibit excellent battery characteristics by performing various experiments.

Specifically, in the present embodiment, as the material of the n-type metal oxide semiconductor layer 16 that is in contact with the charging layer 18, titanium oxide having an anatase crystal structure is used. The anatase type titanium dioxide has a tetragonal crystal structure and is transferred to a rutile type when heated to 900 ° C or higher. By forming the n-type metal oxide semiconductor layer 16 as an anatase type titanium oxide, excellent battery characteristics can be obtained.

As the base film for forming anatase-type titanium oxide, a chromium film or a titanium film is preferable. For this reason, the first electrode 14 is a three-layer structure of chromium/palladium/chromium. That is, as shown in FIG. 2, the first electrode 14 has a chromium (Cr) film 14a and palladium (Pd). The three-layer structure of the film 14b and the chromium (Cr) film 14c. In the first electrode 14, a chromium film 14a, a palladium film 14b, and a chromium film 14c are laminated in this order from the bottom. Thereby, the chromium film 14c becomes the outermost layer of the first electrode 14.

Then, an n-type metal oxide semiconductor layer 16 made of anatase-type titanium oxide is formed over the chromium film 14c. Therefore, the interface of the first electrode 14 that is in contact with the n-type metal oxide semiconductor layer 16 is the chromium film 14c. That is, the chromium film 14c is provided in contact with the n-type metal oxide semiconductor layer 16, and the palladium film 14b is not in contact with the n-type metal oxide semiconductor layer 16.

As a result, an n-type metal oxide semiconductor layer 16 containing anatase titanium dioxide can be formed above the first electrode 14. Here, the difference in the crystal structure of the n-type metal oxide semiconductor layer 16 depending on the substrate (first electrode 14) will be described using FIG.

Fig. 3 is an X-ray diffraction pattern showing a difference in crystal structure of titanium oxide caused by a base film.

In other words, FIG. 3 shows data of an X-ray diffraction pattern (X-ray diffraction spectrum) in a state in which the first electrode 14 and the n-type metal oxide semiconductor layer 16 are formed (hereinafter, referred to as XRD data). schematic diagram.

In Figure 3, the horizontal axis is the diffraction angle 2 θ (incident X-ray direction and winding The angle formed by the X-ray direction), and the vertical axis is the diffraction intensity (cps). In the present embodiment, X-ray diffraction measurement is performed by the θ-2 θ method of CuK α ray having a wavelength of 1.5418 angstroms.

When the crystal lattice spacing is set to d and the X-ray wavelength is set to λ, a peak appears in the X-ray diffraction pattern when ndsin θ=n λ is satisfied (n is 1 or more). Integer). Therefore, the crystal structure of titanium dioxide can be specified based on the value of 2 θ which becomes a peak. For example, in anatase (101), the peak occurs at 2 θ = 25.3 °, while in rutile (110), the peak occurs at 2 θ = 27.4 °.

Fig. 3 shows the results of X-ray diffraction analysis of the sample before the formation of the charging layer 18 as shown in Fig. 2. That is, FIG. 3 shows the results of performing X-ray diffraction analysis in a state where the n-type metal oxide semiconductor layer 16 is exposed. Further, the n-type metal oxide semiconductor layer 16 is subjected to an annealing treatment at the same temperature as the firing step of the charging layer 18. Specifically, X-ray diffraction was performed on a sample annealed at 350 °C.

The XRD data in the case where the first electrode 14 is a three-layer structure of chromium/palladium/chromium (in other words, the case where the substrate is the chromium film 14c) is shown on the lower side of FIG. The XRD data in the case where the first electrode 14 has a two-layer structure of chromium/palladium is shown on the upper side of FIG. Therefore, on the upper side of FIG. 3, the configuration in which the chromium film 14c of FIG. 2 is not provided, that is, the structure in which the base is the palladium film 14b is shown. The measurement results.

In the case where the substrate is the chromium film 14c, the peak of the anatase (101) plane appears at 2 θ = 25.3 ° (see the graph on the lower side of Fig. 3). On the other hand, in the case where the substrate is the palladium film 14b, the peak of the rutile (110) plane appears at 2θ = 27.4° (see the graph on the upper side of Fig. 3). As such, the peak position under the X-ray diffraction varies depending on the base of the n-type metal oxide semiconductor layer 16. In other words, the crystal structure of the n-type metal oxide semiconductor layer 16 varies depending on the base material of the n-type metal oxide semiconductor layer 16. In addition, the inventors of the present application and the like have found that the material of the n-type metal oxide semiconductor layer 16 which can obtain excellent battery characteristics.

Next, the difference in crystal structure caused by the presence or absence of annealing and the difference in the substrate will be described with reference to Figs. 4 to 6 . 4 is a schematic view showing XED data in the case where the first electrode 14 is a three-layer structure of chromium/palladium/chromium. Fig. 5 is a schematic view showing the XRD data in the case where the first electrode 14 is a two-layer structure of chromium/palladium. Fig. 6 is a view showing the XRD data in the case where the first electrode 14 is a two-layer structure of chromium/titanium. In FIGS. 4 to 6, the horizontal axis represents the diffraction angle 2 θ (the angle between the incident X-ray direction and the diffraction X-ray direction), and the vertical axis represents the diffraction intensity (cps).

In other words, Fig. 4 shows an X-ray diffraction pattern in the case where the substrate is used as a chromium film. Fig. 5 is a view showing an X-ray diffraction pattern in the case where a substrate is used as a palladium film. Figure 6 shows the X in the case where the substrate is used as a titanium film. Ray diffraction pattern.

4 to 6 show the results of X-ray diffraction performed in the configuration (the sample before the formation of the charging layer 18) before the formation of the charging layer 18 in the same manner as in FIG. In FIGS. 4 to 6, the XRD data in the case where the upper side is not annealed is shown, and the XRD data in the case where the lower side is annealed is shown. The annealing temperature was set to 350 ° C which was the same as the firing step of the charging layer.

Here, in the case where the substrate is a chromium film or a titanium film, a peak (2 θ = 25.3 °) of the anatase (101) plane may occur (refer to FIG. 4 or FIG. 6). Further, when the base is made of chromium, the peak (2 θ = 25.3 °) of the anatase (101) surface is increased by annealing (see Fig. 4). Thereby, crystallization of titanium dioxide can be promoted by annealing.

When the substrate is a palladium film, a peak of the rutile (110) plane (2 θ = 27.4°) may occur (see Fig. 5). As such, the crystal structure of the n-type metal oxide semiconductor layer 16 changes depending on the base film. Specifically, on the lower side of FIG. 5, the diffraction intensity in 2θ=27.4° becomes higher than the diffraction intensity in 2θ=25.3°.

(battery characteristics)

The battery characteristics when preparing a sample of an oxide semiconductor secondary battery having a base of a chromium film, a palladium film, or a titanium film will be described.

A sample of an oxide semiconductor secondary battery having a chrome film, a palladium film, or a titanium film as an oxide semiconductor secondary battery (chromium), an oxide semiconductor secondary battery (palladium), or an oxide semiconductor secondary battery (titanium). The oxide semiconductor secondary battery (chromium) is a sample of an oxide semiconductor secondary battery in which the first electrode 14 is formed into a three-layer structure of chromium/palladium/chromium. Similarly, the oxide semiconductor secondary battery (palladium) is a sample of the oxide semiconductor secondary battery in which the first electrode 14 is formed into a two-layer structure of chromium/palladium, and the oxide semiconductor secondary battery (titanium) is the first electrode 14 A sample of an oxide semiconductor secondary battery formed into a two-layer structure of chromium/titanium.

In the oxide semiconductor secondary battery (palladium), charging is hardly performed, and sufficient battery characteristics cannot be obtained. Specifically, in an oxide semiconductor secondary battery (palladium), an excessive charging current flows, and it becomes impossible to apply a charging voltage. On the other hand, in an oxide semiconductor secondary battery (chromium) and an oxide semiconductor secondary battery (titanium), it can be appropriately charged, and sufficient battery characteristics can be obtained. That is, since the charging current is not excessively flowed, the charging voltage can be appropriately applied to the charging layer 18.

Therefore, it is preferable that the base film of the n-type metal oxide semiconductor layer 16 be a chromium film or a titanium film. That is, it is preferable to set the outermost layer of the first electrode 14 as a chromium film or a titanium film.

The chromium film or the titanium film of the first electrode 14 is in contact with the lowermost layer of the n-type metal oxide semiconductor layer 16. Thereby, the upper square of the first electrode 14 can be The n-type metal oxide semiconductor layer 16 of an anatase structure is obtained, and excellent battery characteristics can be obtained.

Further, in order to discriminate that the titanium dioxide has an anatase structure or a rutile structure, X-ray diffraction may be used as described above. For example, in X-ray diffraction, the diffraction intensity of the anatase (101) plane (2 θ = 25.3 °) becomes the diffraction intensity of the rutile (110) plane (2 θ = 27.4 °). higher. In other words, the X-ray diffraction pattern obtained by the X-ray diffraction analysis of the n-type metal oxide semiconductor layer 16 by the θ-2 θ method makes the diffraction intensity of the anatase (101) plane become The rutile (110) surface has a higher diffraction intensity. That is, this property can be utilized to discriminate whether the titanium dioxide is an anatase structure or a rutile structure.

(Method of Manufacturing Charging Layer 18)

Next, a method of manufacturing the oxide semiconductor secondary battery 10 will be described with reference to Fig. 7 . Fig. 7 is a flow chart showing a method of manufacturing a secondary battery. In the following description, the configuration of the oxide semiconductor secondary battery 10 will be appropriately described with reference to FIGS. 1 and 2 .

First, the first electrode 14 (S1) is formed on the substrate 12. As shown in FIG. 2, the first electrode 14 has a three-layer structure of a chromium film 14a, a palladium film 14b, and a chromium film 14c. Alternatively, the first electrode 14 may also have a two-layer structure of chromium/titanium. Of course, the structure and the number of layers of the first electrode 14 are not limited to the above-described structure and the number of layers. For example, due to the outermost layer of the first electrode 14, as long as it is a chromium film or titanium The film is sufficient, so that the first electrode 14 can be formed into a single layer structure of a chromium film or a titanium film. Alternatively, the chrome film of the first electrode 14 or the underlying layer of the titanium film may be used as another metal film.

Further, as the material of the substrate 12, for example, a glass substrate or a polyimide (PI) sheet or the like can be used. By using a polyimide film in the substrate 12 and making it flexible, the convenience of use can be improved. Further, as the pre-treatment before the formation of the first electrode 14, the surface of the substrate 12 may be subjected to surface treatment such as ultraviolet irradiation, plasma treatment, or ion treatment. By doing so, the adhesion can be improved.

Next, an n-type metal oxide semiconductor layer 16 is formed over the first electrode 14 (S2). The n-type metal oxide semiconductor layer 16 is formed in contact with a chromium film or a titanium film which is the outermost layer of the first electrode 14. For example, a titanium oxide (TiO ₂ ) film having a thickness of 50 nm to 200 nm is formed on the first electrode 14 by sputtering.

Further, the first electrode 14 and the n-type metal oxide semiconductor layer 16 can be formed by sputtering or the like as described above. Further, the method of forming the first electrode 14 and the n-type metal oxide semiconductor layer 16 is not limited to the sputtering method, and a vapor deposition method, an ion plating method, or MBE (Molecular Beam Epitaxy) can be used. A film forming method such as a method. Further, the first electrode 14 and the n-type metal oxide semiconductor can be formed by a coating forming method such as a printing method or a spin coating method. Body layer 16.

Then, a charging layer 18 is formed over the n-type metal oxide semiconductor layer 16 (S3). An example of the step (S3) of forming the charging layer 18 is shown in FIG. FIG. 8 is a flow chart showing an example of a step of forming the charging layer 18.

First, a fatty acid titanium and eucalyptus oil are mixed in a solvent and stirred to prepare a coating liquid (S31). Next, the prepared substrate 12 is spin-coated on the upper side of the n-type metal oxide semiconductor layer 16 by a spinner while rotating (S32). A thinner layer of 0.3 μm to 1 μm is formed by the rotation of the substrate. In this layer, cerium and titanium dioxide are mixed together. Further, it is not limited to the spin coating method, and may be a dipping coating method, a die coating method, a slit coating method, a gravure coating method, or a spray coating method ( A coating film is formed on the n-type metal oxide semiconductor layer 16 by a spray coating, a curtain coating or the like. Further, the n-type metal oxide semiconductor layer 16 is surface-treated by ultraviolet irradiation or the like before the coating step.

After coating, drying treatment is carried out (S33). For example, the substrate 12 is placed on a hot plate and heated at a predetermined temperature for a predetermined period of time to cause it to function as a solvent in the coating film. As the drying method, it is not limited to the heating plate, and a drying method using heat drying using far infrared rays or a hot air circulation may be used.

After the drying treatment, the charging layer 18 is fired (S34). The firing temperature is preferably set to 300 ° C to 400 ° C. Here, the firing temperature was set to 350 °C. The firing time is from 10 minutes to 1 hour.

The above-described production method for forming the charging layer 18 in which the insulating material and the titanium oxide are mixed together is called a method of applying a thermal decomposition method. As the insulating material, an antimony compound such as cerium oxide is preferably used.

The next manufacturing step is the ultraviolet irradiation step (S35). In this step, the charging layer is irradiated with ultraviolet rays to change the conductivity of the charging layer.

Then, a p-type metal oxide semiconductor layer 20 is formed on the charging layer 18 (S4). For example, a nickel oxide (NiO) film having a thickness of 120 nm to 300 nm is formed as the p-type metal oxide semiconductor layer 20 by sputtering. Further, the method of forming the p-type metal oxide semiconductor layer 20 is not limited to the sputtering method, and a thin film forming method such as a vapor deposition method, an ion plating method, or an MBE method can be used. Further, the p-type metal oxide semiconductor layer 20 may be formed by a coating forming method such as a printing method or a spin coating method.

Next, the second electrode 22 is formed on the p-type metal oxide semiconductor layer 20 (S5). For example, an aluminum film having a thickness of 100 nm to 300 nm is formed by sputtering. In addition, the second electrode 22 is preferably a material having a high electrical conductivity, that is, a resistivity. The lower material, for example, is preferably a material having a resistivity of 100 μΩ ̇ cm or less.

In addition, the method of forming the second electrode 22 is not limited to the sputtering method, and a thin film forming method such as a vapor deposition method, an ion plating method, or an MBE (Molecular Beam Epitaxy) method can be used. Further, the second electrode 22 may be formed by a coating forming method such as a printing method or a spin coating method.

In this way, the oxide semiconductor secondary battery 10 is completed. As described above, the n-type metal oxide semiconductor layer 16 is titanium dioxide having an anatase structure. Thus, excellent battery characteristics can be obtained.

Alternatively, the n-type metal oxide semiconductor layer 16 may be changed to an anatase structure on the way of the manufacturing step. For example, the amorphous structure may be formed in the step (S2) of forming the n-type metal oxide semiconductor layer 16, and the amorphous structure may be changed to an anatase structure by the firing step (S35). For example, as shown in FIG. 4, the annealed n-type metal oxide semiconductor layer 16 has a higher diffraction intensity of the anatase (101) plane than before annealing. Thereby, the anatase-structured titanium oxide can be formed by heating the n-type metal oxide semiconductor layer 16 after the formation of the n-type metal oxide semiconductor layer 16. In other words, the manufacturing step of the oxide semiconductor secondary battery 10 may have a heating step of changing the titanium oxide into an anatase structure.

As described above, the base of the n-type metal oxide semiconductor layer 16 is a chromium film or a titanium film. By doing so, the n-type metal oxide semiconductor layer 16 can be formed into an anatase structure of titanium oxide.

In the above description, the n-type metal oxide semiconductor layer 16 is formed of titanium dioxide having an anatase structure, but the n-type metal oxide semiconductor layer 16 may be an amorphous titanium oxide. Even in the case where the n-type metal oxide semiconductor layer 16 is formed into an amorphous structure of titanium oxide, excellent battery characteristics can be obtained.

[Table 1]

The XRD data in the case where the n-type metal oxide semiconductor layer 16 is an anatase structure or a rutile structure of titanium dioxide is shown in Table 1 and Table 2. Table 1 is a graph showing XRD data of an anatase structure. Table 2 is a graph showing XRD data of the rutile structure. Further, for reference, Table 3 shows XRD data of chromium, and Table 4 shows XRD data of palladium.

In addition, Table 1 is published in Natl. Bur. Stand. (U.S.) Monogr. 25, details of volume. 7, page 82 (1969). Table 2 is published in Natl. Bur. Stand. (U.S.) Monogr. 25, detail volume. 7, page 83 (1969). Table 3 is published in Natl.Bur.Stand. (U.S.), Circ.539, details are Volume.V, page 20 (1955), and the producer is Swanson et al. Table 4 is published in Natl. Bur. Stand. (U.S.), Circ. 539, details volume. I, page 21 (1953), producer Swanson, Tatge.

In the case of an anatase structure, there is a peak at 2 θ = 25.281°. In the amorphous structure and the anatase structure, the battery characteristics are excellent. In the rutile structure, there is a peak in 2 θ = 27.447 °. In the rutile structure, excellent battery characteristics are not shown. Therefore, as long as titanium dioxide is used as a structure other than the rutile structure, excellent battery characteristics can be obtained. For example, the X-ray diffraction intensity of 2 θ = 27.4° corresponding to rutile (110) becomes lower than the X-ray diffraction intensity of 2 θ = 25.3° corresponding to anatase (101).

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiments, and the present invention is not limited to the above embodiments.

The present application claims priority on the basis of Japanese Patent Application No. 2015-171104, filed on Jan. 31, 2015, the entire disclosure of which is incorporated herein.

10‧‧‧Oxide semiconductor secondary battery

12‧‧‧Substrate

14‧‧‧First electrode

16‧‧‧n type metal oxide semiconductor layer

18‧‧‧Charging layer

20‧‧‧p-type metal oxide semiconductor layer

22‧‧‧second electrode

Claims (11)

An oxide semiconductor secondary battery comprising: a first electrode; an n-type metal oxide semiconductor layer formed over the first electrode; and a charging layer formed over the n-type metal oxide semiconductor layer, and a material comprising an n-type metal oxide semiconductor and an insulating material; a p-type metal oxide semiconductor layer formed over the charging layer; and a second electrode formed on the p-type metal oxide semiconductor layer The n-type metal oxide semiconductor layer contains titanium dioxide having an anatase structure or an amorphous structure. The oxide semiconductor secondary battery according to claim 1, wherein the n-type metal oxide semiconductor layer is titanium dioxide having an anatase structure. The oxide semiconductor secondary battery according to claim 2, wherein the outermost layer of the first electrode is formed of a chromium film, and the n-type metal oxide semiconductor layer is in contact with the chromium film. The oxide semiconductor secondary battery according to claim 2, wherein the outermost layer of the first electrode is formed of a titanium film, and the n-type metal oxide semiconductor layer is in contact with the titanium film. The oxide semiconductor secondary battery according to any one of claims 2 to 4, wherein the X-ray diffraction obtained by X-ray diffraction measurement of the θ-2 θ method on the n-type metal oxide semiconductor layer is obtained. In the shot pattern, the diffraction intensity of the anatase (101) plane becomes higher than the diffraction intensity of the rutile (110) plane. A method for producing an oxide semiconductor secondary battery comprising: a step of forming a first electrode; a step of forming an n-type metal oxide semiconductor layer made of titanium oxide over the first electrode; and the n-type metal oxide a step of forming a charging layer composed of a substance containing an n-type metal oxide semiconductor and an insulating substance over the semiconductor layer; a step of forming a p-type metal oxide semiconductor layer over the charging layer; and the aforementioned p-type metal A step of forming a second electrode above the oxide semiconductor layer; the n-type metal oxide semiconductor layer containing titanium dioxide having an anatase structure or an amorphous structure. The method for producing an oxide semiconductor secondary battery according to claim 6, wherein the n-type metal oxide semiconductor layer is titanium dioxide having an anatase structure. The method for producing an oxide semiconductor secondary battery according to claim 7, wherein the outermost layer of the first electrode is formed of a chromium film, and the n-type metal oxide semiconductor layer is in contact with the chromium film. The method for producing an oxide semiconductor secondary battery according to claim 7, wherein the outermost layer of the first electrode is formed of a titanium film, and the n-type metal oxide semiconductor layer is in contact with the titanium film. The method for producing an oxide semiconductor secondary battery according to any one of claims 7 to 9, wherein the n-type metal oxide semiconductor layer is formed by heating the n-type metal oxide semiconductor layer. The titanium dioxide of the aforementioned anatase structure is formed. The method for producing an oxide semiconductor secondary battery according to any one of claims 7 to 9, wherein the n-type metal oxide semiconductor layer is subjected to X-ray diffraction measurement by the θ-2 θ method. In the X-ray diffraction pattern, the diffraction intensity of the anatase (101) plane becomes higher than the diffraction intensity of the rutile (110) plane.