WO2012098647A1

WO2012098647A1 - Semiconductor device and system using same

Info

Publication number: WO2012098647A1
Application number: PCT/JP2011/050772
Authority: WO
Inventors: 正成藤森; 小島　恭子; 龍崎　大介
Original assignee: 株式会社日立製作所
Priority date: 2011-01-18
Filing date: 2011-01-18
Publication date: 2012-07-26
Also published as: JP5608759B2; JPWO2012098647A1

Abstract

The purpose of the present invention is to provide a structure wherein recombination of carriers arising with irradiation of thin-film or bulk semiconductors by light can be suppressed and extraction to electrodes is made easy. Therefore, a semiconductor film is formed on a substrate, and the axis of electrical polarization of a piezoelectric body is disposed so as to pass through the semiconductor film in a state of alignment with the direction of film thickness of the semiconductor.

Description

Semiconductor device and system using the same

The present invention relates to charge separation of photogenerated carriers involved in the generation of energy, decomposition of substances, and synthesis by applying oxidation / reduction reactions such as solar cells, water, and carbon dioxide.

When light is incident on the semiconductor material, the light is absorbed by the semiconductor in accordance with the distance that the light passes through the semiconductor material and the absorption rate specific to the material with respect to the energy of the incident light. The reality of absorbing light is semiconductor electrons and phonons. When light emitted from the sun is used as electricity, absorption of light by electrons is important for generating electrical energy. On the energy scale of sunlight, light is absorbed by electrons in the valence band and excites the electrons into the conduction band. Holes are formed in the valence band because electrons are lost. Electrons have a minus sign and holes have a plus sign, and are loosely bound by the Coulomb force screened by the dielectric constant of the crystal (exciton). In ordinary inorganic semiconductors, this binding energy is small, and excitons dissociate at room temperature. In this case, the excited electrons and holes generated by the light irradiation are diffused and uniformly distributed in the light irradiated region. After that, electrons and holes recombine within the lifetime determined according to the semiconductor type and defect density, impurity type and concentration, energy level, surface condition, etc. Disappears.

When converting solar energy into electrical energy, it is necessary to separate the space into different regions before taking out electrons and holes before recombining them. In general solar cells, except for the dye-sensitized type, the distribution of electrons and holes (carriers) is biased by a pn junction. Minority carriers generated by light absorption (electrons in the p-type region and holes in the n-type region) are diffused toward the pn junction by the gradient of the electrochemical potential, and reach the majority carrier region within the lifetime described above. Is used as electricity.

When water, carbon dioxide, etc. are decomposed by oxidation / reduction reactions to obtain substances that become energy sources such as hydrogen, methane, alcohol, etc., first, the electrons and holes generated by the light absorption of the semiconductor are separated, and then separated into different electrodes Take out. Each electrode is prepared so as to function as a reduction electrode and an oxidation electrode, and an oxidation / reduction reaction is caused on each electrode to obtain a material serving as an energy source. Therefore, it is the same as that of a solar cell until light energy is converted into electric energy. The difference from a solar cell is that chemical energy is obtained in the form of a substance by using electric energy obtained by converting light energy for a chemical reaction.

The part that converts light energy into electrical energy can use the structure of the solar cell as it is. The method using solar cells is the most efficient method for conversion from light to electricity and has great advantages. However, making the solar cell structure itself is a costly method requiring a complex process. For this reason, when a chemical substance that is an energy source is generated using light, a method of converting light into electric energy by a simpler method is often used. For example, a semiconductor single layer and a metal are joined, and each of them is used as an oxidation / reduction electrode, and conversion of light into electric energy can be performed in the semiconductor single layer. In this case, the probability that the carriers generated by light recombine before reaching the oxidation / reduction electrode by diffusion is higher than that of the pn junction. That is, there is a problem that carriers generated by light are not used for oxidation / reduction reactions and are lost. This problem deteriorates the conversion efficiency of light energy into a product by oxidation / reduction reaction.

One solution is to adopt a structure in which the diffusion length is short so that the carriers are taken into the electrode before recombining. The most typical example is a method using semiconductor fine particles. By bonding metal fine particles to the surface of the semiconductor fine particles and using the semiconductor portion and the metal portion as oxidation / reduction electrodes, respectively, the diffusion length of the carriers generated by light is at most about the fine particle size. For example, Patent Document 1 discloses an example of such a method.

Further, Patent Document 2 discloses that organic substance decomposition is performed using a composite of a piezoelectric body and a semiconductor.

Patent Document 3 discloses a structure in which manganese oxide particles are arranged on titanium oxide for the purpose of reducing the recombination rate of photogenerated electrons and holes.

JP 2009-063221 A JP 2002-079068 A JP 2006-528055 A

In the present invention, a thin film or a bulk semiconductor is used for carrier generation. On the other hand, the method using fine particles disclosed in Patent Document 1 can increase the surface area per volume as compared with the case of using a thin film or a bulk semiconductor, and therefore it is easy to increase the frequency at which oxidation / reduction reactions occur. In addition, it is often used by being dispersed in water, which has the advantage of increasing the absorption probability due to irregular reflection of light. However, carriers are not separated into the semiconductor film surface and the substrate interface as in the present invention, and recombination of carriers across fine particles is likely to occur due to contact between the fine particles, and it is difficult to prevent them. Also, the period during which the oxidation / reduction reaction can be maintained is short.

Further, the composite disclosed in Patent Document 2 is formed by sintering powder, and the electric polarization axis of the piezoelectric body faces a random direction. Therefore, only a local charge separation effect can be expected, and carrier recombination tends to occur.

Furthermore, the configuration disclosed in Patent Document 3 does not separate carriers on the surface of the semiconductor film and the substrate interface as in Patent Document 1, and the effect of suppressing the recombination of carriers only affects locally.

In view of such circumstances, it is an object of the present application to provide a structure that makes it easy to take out to an electrode by suppressing recombination of carriers generated by irradiating light to a thin film or a bulk semiconductor. .

A typical one of the inventions disclosed in the present application will be briefly described as follows. That is, the semiconductor device includes a substrate, a semiconductor film formed in contact with the substrate on the first surface and generating carriers by light irradiation, and a piezoelectric body disposed in the semiconductor film. Semiconductor device in which the electric polarization axis of the piezoelectric body is aligned with respect to the film thickness direction of the semiconductor film, and is arranged so as to be continuously distributed between the first surface and the second surface facing the first surface It is.

In addition, when a strain is applied to the piezoelectric body, the substrate has a semiconductor film formed in contact with the substrate on the first surface and generates a carrier by light irradiation, and a piezoelectric body disposed in the semiconductor film. In the semiconductor device, the direction of the electric field generated around the piezoelectric body and between the first surface of the semiconductor film and the second surface facing the first surface is the film thickness direction of the semiconductor film. .

A semiconductor device that includes a semiconductor device that generates carriers by light irradiation and a container having a translucency and a structure that fills the periphery of the semiconductor device with a fluid, and extracts a product generated by a redox reaction by the carriers This is a system using a device. The semiconductor device includes a substrate, a semiconductor film formed in contact with the substrate on a first surface and generating carriers, and a piezoelectric body disposed in the semiconductor film, and the piezoelectric body is a first surface of the semiconductor film. And the second surface facing the first surface are arranged so as to be continuously distributed, and the electric polarization axis of the piezoelectric body is aligned with the film thickness direction of the semiconductor film.

According to the present invention, recombination of carriers generated by irradiating light to a thin film or a bulk semiconductor can be suppressed, and the film can be easily taken out to the electrode.

1 is a diagram illustrating an example of a semiconductor device according to a first embodiment. It is a figure which shows the cross-sectional structure of Fig.1 (a). FIG. 6 is a diagram illustrating an example of a semiconductor device according to a second embodiment. FIG. 6 is a diagram illustrating an example of a semiconductor device according to a third embodiment. FIG. 6 is a diagram illustrating an example of a semiconductor device according to a third embodiment. It is a schematic diagram of the energy band in the film thickness direction inside the semiconductor (position A in FIG. 1B) in a state where strain is applied. It is a schematic diagram of the energy band in the film thickness direction inside the semiconductor (position A in FIG. 1B) when no strain is applied. It is a schematic diagram of the energy band of the in-film parallel direction in the semiconductor (position A in FIG. 1B) when a piezoelectric body is present. It is a schematic diagram of the energy band in the in-film parallel direction inside the semiconductor (position B in FIG. 1B) when there is no piezoelectric body. It is a figure which shows an example of the state which formed the piezoelectric material thin film on the board | substrate. It is a figure which shows an example of the state which made the piezoelectric material grow on the piezoelectric material thin film. It is a figure which shows an example of the state which apply | coated the resist for patterning a piezoelectric material on a piezoelectric material. It is a figure which shows an example of the state which patterned the resist. It is a figure which shows an example of the state which patterned the piezoelectric material by the etching. It is a figure which shows an example of the state which formed the semiconductor film on the board | substrate. It is a figure which shows an example of the state which etched the resist and lifted off the semiconductor which remains on a columnar piezoelectric material. 6 is a schematic view of a photomask pattern that realizes a semiconductor device according to Example 3. FIG. 6 is a schematic view of a photomask pattern that realizes a semiconductor device according to Example 3. FIG. It is a conceptual diagram which shows an example of the system using the semiconductor device of a present Example.

Example 1
In this embodiment, a structure in which a one-dimensional columnar piezoelectric body, which is one embodiment of the present invention, is embedded in a semiconductor responsible for generating optical carriers is described.

In this embodiment, a structure in which an electrostatic potential is spontaneously applied to a semiconductor that generates carriers by light irradiation is added, thereby providing a mechanism in which positive and negative carriers drift in directions opposite to each other. The main feature is the structure that can. Here, “spontaneous” is used to mean that energy is not consciously supplied from the outside.

FIG. 1A is a diagram showing a state in which a columnar piezoelectric body 12 is embedded in a semiconductor film 11 that generates optical carriers on a substrate 10. FIG.1 (b) is sectional drawing in the surface containing a piezoelectric material of Fig.1 (a).

One of the features of the columnar piezoelectric body 12 is that it is arranged so as to penetrate the semiconductor film 11 almost. The piezoelectric body 12 may have a shape that completely penetrates the semiconductor film 11, or the surface of the piezoelectric body 12 and the surface of the semiconductor film 11 may coincide with each other. Furthermore, the surface of the piezoelectric body 12 may be in a state where it is buried to some extent inside the semiconductor film 11. Here, “a certain degree” means a distance such that the surface affects the inside of the semiconductor film 11 and is characterized as a range in which the energy band of the semiconductor is bent due to the influence of the surface.

Also, one of the features of the columnar piezoelectric body is that the electric polarization axes are aligned. When strain is applied to the substrate in such a state, strain is applied to the columnar piezoelectric body via the substrate or the thin film, and positive and negative charges are generated on the end surfaces of the columnar piezoelectric body. By arranging the piezoelectric body so that the end face where the charge is generated corresponds to the surface of the semiconductor film 11 and the substrate interface, an electric field is applied between the surface of the film and the substrate interface around the piezoelectric body. If the pressure applied to the semiconductor thin film is the same type (either tensile or compressive stress) within the film, the electric field direction between the surface of the semiconductor thin film and the interface can be obtained by aligning the electric polarization axes of the piezoelectric body. Can be unified. Although the intensity varies with time, an electric field is generated in the film thickness direction of the semiconductor film, and electrons and holes drift in the determined directions, so that positive and negative carriers can be easily taken out by the determined electrodes.

FIG. 4A is a diagram for explaining this situation, and shows an energy band of the semiconductor film 11 in a state where a strain at a position A in FIG. 1B is applied. The horizontal axis represents the position in the depth direction indicated by A in FIG. 1B, and the vertical axis represents energy. In a state where strain is applied, the conduction band 13 and the valence band 15 are bent by the positive and negative charges generated at both ends of the columnar piezoelectric body, and the bottom 20 of the conduction band and the upper end 21 of the valence band are in the depth direction of the film. Therefore, the electrons 16 and the holes 17 which are carriers generated by light are separated from each other on the left and right in the drawing according to the inclination of the band. Reference numeral 14 in the figure indicates a forbidden band in the semiconductor.

On the other hand, in the state where no strain is applied, the energy band is bent only in the vicinity of the surface only by the influence of the semiconductor film surface. As a result, as shown in FIG. 4B, the electrons 16 and the holes 17 generated by the light absorbed in the vicinity of the semiconductor film surface 18 are separated by the bending of the band. Limited to the vicinity.

In addition, even if no strain is applied inside the semiconductor, an energy band bends at the interface between the semiconductor and the piezoelectric body as long as the Fermi energy of the semiconductor and the piezoelectric body does not match. As a result, in the vicinity of the interface between the semiconductor and the piezoelectric material, the electron-hole pairs generated by light absorption are affected by the bending of the energy band so that they receive forces in different directions, and the distance between them is spatially reduced. A drift motion is generated to hold. As a result, electrons and holes tend to have spatially different distributions, and the recombination frequency decreases.

FIG. 5 (a) is a diagram for explaining this situation, and shows an energy band at a position B in FIG. 1 (b). The vertical axis represents energy, and the horizontal axis represents the position in the horizontal direction. Since the conduction band 13 and the valence band 15 are bent near the interface 19 between the semiconductor film 11 and the piezoelectric body 12, the electrons 16 and the holes 17 generated in the vicinity of the semiconductor film 11 and the valence band 15 are in directions opposite to each other depending on whether the charge is positive or negative. You will receive power.

FIG. 5 (b) depicts an energy band at the same location when there is no piezoelectric body. Since the uniform semiconductor layer continues, the conduction band 13 and the valence band 15 do not bend.

As described above, the piezoelectric material is arranged so as to be continuously distributed between the surface of the semiconductor film and the substrate interface, and the electric polarization axis is aligned with respect to the film thickness direction, so that strain is applied. Although there is a difference between the relaxed state and the relaxed state, the electrons and holes generated by the absorption of light are each subjected to a force in the opposite direction, and are distributed in a spatially separated state. To do. Thereby, it becomes easy to take out to an electrode, suppressing recombination of a carrier.

As will be described later, the form of the piezoelectric body is not limited to the columnar shape. Any structure may be used as long as the electric polarization axes are aligned and continuously exist between the surface of the semiconductor thin film responsible for light generation and the substrate interface.

An example of a process for realizing this structure will be described with reference to FIG. First, a zinc oxide (ZnO) thin film 22 is formed as a piezoelectric body on a substrate 10 made of silicon (Si) (FIG. 6A). For example, ZnO with a film thickness of about 100 nm can be formed by reactive RF magnetron sputtering in a mixed atmosphere of oxygen and argon using Zn as a target. A ZnO film 12 oriented in the c-axis direction is formed on this thin film by a hydrothermal synthesis method (FIG. 6B). A 4 wt% aqueous ammonia solution is added to an aqueous solution in which 20 mM zinc chloride (ZnCl ₂ ) and 20 mM hexamethylenetetramine are dissolved, and the temperature is maintained at 95 ° C. The previous substrate is brought into contact therewith with the ZnO surface facing downward, and is held for about 1 hour to obtain a ZnO thin film having a film thickness of about 1 μm and oriented on the c-axis.

Next, the ZnO film is patterned by photolithography to form a one-dimensional cylindrical ZnO that stands upright in the direction perpendicular to the substrate. A resist thin film 23 is applied to the substrate by spin coating and baked by a hot plate (FIG. 6C). It exposes with the photomask which has a pattern in which a circular resist remains periodically, and develops suitably. As a result, as shown in FIG. 6D, a pattern of the circular island-shaped resist thin film 23 remains on the ZnO film. By etching this substrate with phosphoric acid (H ₃ PO ₄ ), cylindrical ZnO as shown in FIG. 6E is formed on the substrate 10. Thereafter, as shown in FIG. 6F, titanium dioxide (TiO ₂ ) 28 is sputtered to embed cylindrical ZnO in TiO ₂ . The remaining resist is removed by wet etching to lift off the TiO ₂ formed on the cylindrical ZnO. In this way, a desired structure as shown in FIG. In this state, the columnar ZnO may be completely embedded by further forming a film of TiO ₂ .

Here, the details of patterning are omitted, but only the outline is described, but details of photolithography including the necessity of selecting a mask inversion pattern according to the film forming and etching, resist coating / baking conditions, and resist negative / positive, etc. It will be apparent to those skilled in the art.

Thus the aluminum is deposited on the back surface of the structure to the substrate, a tin-doped indium oxide (ITO) as a transparent electrode on the surface while the deposition, although the TiO ₂ is absorbed irradiated with 365nm light absorption is small with respect to ITO The photocurrent was measured. For comparison, except that there is no cylindrical ZnO, the photocurrent was measured by applying light to a substrate having the same film thickness and the like. The former had more photocurrent for the same intensity of light. It was confirmed that it could be taken out.

Also, the structure in which the piezoelectric body is cylindrical is suitable for a structure in which the piezoelectric body grows in a nanowire shape. Examples thereof include ZnO crystal growth on a GaN or sapphire substrate. In this case, since the lattice constants are matched, the film can be grown by direct hydrothermal synthesis without sputter deposition. Furthermore, there is a great advantage that molding by photolithography is unnecessary.

In this example, ZnO was used as the piezoelectric body, but quartz, potassium phosphate, barium titanate, zinc titanate zirconate, Rochelle salt, zinc oxide, lithium niobate, lithium tantalate, lithium tetraborate, langasite, Other piezoelectric materials such as aluminum nitride, tourmaline, and sodium nitrite may be used.

Further, although Si is used for the substrate, it is not limited thereto. Necessary structures can be configured in the same manner with glass, plastic plastic substrates, and metal substrates.

Furthermore, the semiconductor that generates the optical carriers is not limited to TiO ₂ , and SiC, GaN, GaP, GaAs, CdSe, CdS, Fe ₂ O ₃ , SrTiO ₃ , Bi ₂ O ₃ , FeTiO ₃ , MnTiO ₃ , Any type of semiconductor may be used as long as it has absorption near visible light, such as BaTiO ₃ , KTaO ₃ , WO ₃ , SnO ₂ , NbO ₂ , and Nb ₂ O ₃ .

(Example 2)
FIG. 2 shows a semiconductor device according to Embodiment 2 of the present invention. This embodiment is characterized by having a prismatic piezoelectric structure. In this embodiment, a prismatic piezoelectric structure can be obtained by changing the photomask pattern with respect to the semiconductor device manufacturing method described in the first embodiment.

(Example 3)
In the first embodiment, an example in which the piezoelectric body has a columnar structure has been described. In this embodiment, an example using a piezoelectric body having a plate-like structure as shown in FIG. 3 will be described. The manufacturing method of the semiconductor device of this example is exactly the same as the method disclosed in Example 1 until the piezoelectric ZnO is grown by the hydrothermal synthesis method and the resist is applied.

Thereafter, exposure is performed using a photomask having a pattern in which slits are periodically arranged as shown in FIG. Thereafter, in the same manner as in Example 1, etching, semiconductor film formation, lift-off, film formation again if necessary, the structure as shown in FIG. 3A, the piezoelectric body 12 is unidirectional within the plane of the semiconductor film 11 A structure extending linearly is obtained. In this structure, since the piezoelectric bodies are continuously distributed, there is an advantage that the influence of the potential due to strain is widely spread when the piezoelectric bodies are arranged with the same period as compared with the columnar shape. Furthermore, since the area of the interface between the semiconductor and the piezoelectric body is widened, there is an advantage that the effect of bending the energy band due to the interface is more widely spread.

The arrangement of continuous piezoelectric bodies is not limited to that shown in FIG. For example, using a photomask as shown in FIG. 7B, the structure as shown in FIG. 3B and the piezoelectric body 12 divide the semiconductor film 11 into a lattice shape in the same manner as the method disclosed in the first embodiment. A structure arranged in this manner can be obtained. Such a structure has an advantage that the influence of electric charges generated by strain is stronger and extends to the semiconductor layer as compared with FIG. Furthermore, there is an advantage that the influence of the interface extends over a wider area. On the other hand, the configuration shown in FIG. 3A has an advantage that light easily hits a wide range as compared with FIG. This advantage is more conspicuous in the configurations of FIGS. 1A and 2 than in the configurations of FIGS. 3A and 3B.

Example 4
In this embodiment, a system using a semiconductor device that efficiently extracts photogenerated carriers described in Embodiments 1 to 3 will be described with reference to FIG.

The semiconductor device 24 as described in the first to third embodiments is fixed inside the installation box 25. The installation box 25 has a structure that fills the periphery of the semiconductor device 24 by introducing a fluid such as gas or liquid. Reference numeral 26 in the figure is an inlet for introducing a fluid, and reference numeral 27 is an outlet for extracting the fluid from the installation box. At least the upper surface of the installation box 25 is formed of a transparent surface so that light can be taken inside. The semiconductor device 24 is mechanically fixed in the installation box. As a result, thermal strain due to heat due to sunlight irradiation, mechanical strain due to installation with mechanical stress applied, and strain due to film strain at the time of thin film deposition are introduced.

From the inlet 26, for example, a solution in which carbon dioxide is dissolved at a high concentration is introduced to fill the inside of the installation box 25, and sunlight is irradiated from the upper surface. Light incident from the surface of the semiconductor device 24 is absorbed in the semiconductor and generates photocarriers (a pair of electrons and holes). When the above-described strain is applied to the piezoelectric body, the generated photocarriers efficiently separate electrons and holes as described in the first embodiment and reach the front surface and the back surface of the semiconductor device 24, respectively. . These carriers oxidize and reduce carbon dioxide or a dissolved product thereof on each surface of the semiconductor device 24 to generate decomposition products. When the product is a gas, a gas outlet is provided on the upper surface of the installation box and is taken out to the outside. In the case of liquid, it is carried out from the outlet.

As described above, by using the semiconductor device described in the first to third embodiments, carrier recombination is suppressed and it is easy to take out, and as a result, a decomposition product due to oxidation-reduction reaction by the carrier is efficiently generated and taken out. It becomes possible.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made. Those skilled in the art can appropriately combine the above-described embodiments. Will be understood.

DESCRIPTION OF SYMBOLS 10 Substrate 11 Semiconductor film 12 Piezoelectric 13 Conductive band 14 Forbidden band 15 Valence band 16 Electron 17 Hole 18 Semiconductor film surface 19 Interface 20 Bottom of conduction band 21 Upper end of valence band 22 Zinc oxide thin film 23 Resist thin film 24 Semiconductor device 25 Installation box 26 Inlet 27 Outlet 28 Titanium dioxide

Claims

A substrate,
A semiconductor film formed in contact with the substrate on the first surface and generating carriers by light irradiation;
A piezoelectric body disposed in the semiconductor film,
The piezoelectric body is disposed so as to be continuously distributed between the first surface of the semiconductor film and a second surface facing the first surface,
A semiconductor device in which an electric polarization axis of the piezoelectric body is aligned with a film thickness direction of the semiconductor film.
The semiconductor device according to claim 1,
A semiconductor device in which the piezoelectric body is disposed so as to penetrate the semiconductor film.
The semiconductor device according to claim 1,
The piezoelectric body is made of quartz, potassium phosphate, barium titanate, zinc zirconate titanate, Rochelle salt, zinc oxide, lithium niobate, lithium tantalate, lithium tetraborate, langasite, aluminum nitride, tourmaline, sodium nitrite. A semiconductor device made of either.
The semiconductor device according to claim 1,
The semiconductor film is made of TiO 2 , SiC, GaN, GaP, GaAs, CdSe, CdS, Fe 2 O 3 , SrTiO 3 , Bi 2 O 3 , FeTiO 3 , MnTiO 3 , BaTiO 3 , KTaO 3 , WO 3 , SnO 2. , NbO 2 , or Nb 2 O 3 .
The semiconductor device according to claim 1,
A semiconductor device in which a plurality of the piezoelectric bodies are independently arranged in the semiconductor film.
The semiconductor device according to claim 5,
A semiconductor device in which a cross-sectional shape of the piezoelectric body in an in-plane direction of the semiconductor film is a circular or square shape.
The semiconductor device according to claim 1,
The piezoelectric device is a semiconductor device having a structure extending linearly in one direction within the surface of the semiconductor film.
The semiconductor device according to claim 1,
The piezoelectric device is a semiconductor device arranged to divide the semiconductor film into a lattice shape.
A substrate,
A semiconductor film formed in contact with the substrate on the first surface and generating carriers by light irradiation;
A piezoelectric body disposed in the semiconductor film,
The direction of the electric field generated between the first surface of the semiconductor film and the second surface facing the first surface when the strain is applied to the piezoelectric material Is a semiconductor device in the thickness direction of the semiconductor film.
The semiconductor device according to claim 9.
The piezoelectric body is made of quartz, potassium phosphate, barium titanate, zinc zirconate titanate, Rochelle salt, zinc oxide, lithium niobate, lithium tantalate, lithium tetraborate, langasite, aluminum nitride, tourmaline, sodium nitrite. A semiconductor device made of either.
The semiconductor device according to claim 9.
The semiconductor film is made of TiO 2 , SiC, GaN, GaP, GaAs, CdSe, CdS, Fe 2 O 3 , SrTiO 3 , Bi 2 O 3 , FeTiO 3 , MnTiO 3 , BaTiO 3 , KTaO 3 , WO 3 , SnO 2. , NbO 2 , or Nb 2 O 3 .
The semiconductor device according to claim 9.
A plurality of the piezoelectric bodies are independently arranged in the semiconductor film,
A semiconductor device in which a cross-sectional shape of the piezoelectric body in an in-plane direction of the semiconductor film is a circular or square shape.
The semiconductor device according to claim 9.
The piezoelectric device is a semiconductor device having a structure extending linearly in one direction within the surface of the semiconductor film.
The semiconductor device according to claim 9.
The piezoelectric device is a semiconductor device arranged to divide the semiconductor film into a lattice shape.
A system that includes a semiconductor device that generates carriers by light irradiation, and a container that has translucency and has a structure that fills the periphery of the semiconductor device with a fluid, and that extracts a product generated by an oxidation-reduction reaction by the carriers. There,
The semiconductor device includes:
A substrate,
A semiconductor film formed in contact with the substrate at a first surface and generating the carrier;
A piezoelectric body disposed in the semiconductor film,
The piezoelectric body is disposed so as to be continuously distributed between the first surface of the semiconductor film and a second surface facing the first surface,
A system using a semiconductor device, wherein the electric polarization axis of the piezoelectric body is aligned with the film thickness direction of the semiconductor film.