JP2014212216A - Photovoltaic power module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photovoltaic power module including a metal silicide layer having high power generation efficiency.SOLUTION: A photovoltaic power module of an embodiment comprises a lamination structure including an electrode layer, a metal oxide layer, and a semiconductor layer composed of a metal silicide layer composed of one kind of β-FeSior BaSi. The metal oxide layer is preferably an SiOlayer. The thickness of the metal oxide layer is preferably not more than 5 nm. The metal oxide layer is preferably a Schottky type. The electrode layer is preferably an electrode layer composed of one kind of NiSior CoSi.

Description

Embodiments described below generally relate to photovoltaic modules.

Solar cells using sunlight are attracting attention as clean electric energy. As solar cells, those using a single crystal silicon substrate or a polycrystalline silicon substrate are mainly used because of their excellent power generation efficiency. In addition, the use of thin-film amorphous silicon obtained by reducing the thickness of a silicon substrate has been studied for cost reduction. In addition, compound semiconductor solar cells using gallium, arsenic, phosphorus, germanium, indium or the like are also known as non-silicon solar cells. Conventional solar cells have a problem that the cost is high due to the increase in the size of the silicon substrate that receives sunlight and the complexity of the compound synthesis process, and the diffusion of the solar cell does not proceed as expected.
In recent years, solar cells using metal silicide as a semiconductor layer have been studied. For example, JP-A-20
11-198941 (Patent Document 1) discloses a solar cell using a β-FeSi ₂ layer as a semiconductor layer. A metal silicide such as iron silicide can be produced as either a single crystal or a polycrystal, and is expected to be lower in cost than a silicon-based solar cell. In addition, since metal silicide solar cells generate power by sensing infrared rays that are not used in silicon solar cells, there are expectations for higher efficiency than silicon solar cells.
However, solar cells using a metal silicide layer are not commercialized at present and are in the research stage. This is because stable power generation efficiency cannot be obtained. Moreover, since the output of a solar cell using a metal silicide layer fluctuates depending on the intensity of received light, there was anxiety in use as a single power source.

JP 2011-198941 A

The problem to be solved by the present invention is to provide a photovoltaic power generation module using a metal silicide layer with good power generation efficiency. The present invention also provides a solar power generation module that enables stable power supply that is resistant to changes in light intensity, that is, changes in the amount of sunlight.

The photovoltaic power generation module according to the embodiment has a laminated structure of an electrode layer made of one kind of NiSi 2 or CoSi, a metal oxide layer, and a semiconductor layer made of a metal silicide layer made of one kind of β-FeSi ₂ or BaSi _2. It is characterized by.

It is a schematic diagram for illustrating the photovoltaic power generation module according to the first embodiment. It is a schematic diagram for illustrating the semiconductor layer which consists of a metal silicide layer. It is a schematic diagram for illustrating the photovoltaic power generation module according to the second embodiment. It is a schematic diagram for illustrating the electrical storage mechanism part of this embodiment. It is a schematic graph for demonstrating the IV characteristic of the solar power generation module which concerns on 2nd embodiment.

Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.
FIG. 1 is a schematic view for illustrating the photovoltaic power generation module according to the first embodiment.
In the figure, 1 is a solar power generation module according to the first embodiment, 2 is a semiconductor layer made of a metal silicide layer, 3 is an electrode layer, 4 is a metal oxide layer, 5 is a substrate, and 6 is a surface electrode portion. is there.
The surface electrode portion 6 is provided on the front surface side (sunlight receiving surface side) of the semiconductor layer 2 made of a metal silicide layer, and the metal oxide layer 4 and the electrode layer 3 are provided on the back surface side (opposite to the sunlight receiving surface). Yes.
The semiconductor layer 2 made of a metal silicide layer is a metal silicide layer made of β-FeSi ₂ or BaSi ₂ . A metal oxide layer 4 is formed between the semiconductor layer 2 made of a metal silicide layer and the electrode layer 3. If the stoichiometry approximates to FeSi ₂ (the first decimal place is rounded to the atomic ratio Fe: Si = 1: 2), it can be used even if it is slightly deviated. Similarly, as long as the stoichiometry is approximated to BaSi ₂ (the first decimal place is rounded off so that the atomic ratio Ba: Si = 1: 2), it can be used even if it is slightly deviated.

By providing the metal oxide layer 4, the band gap of the semiconductor layer 2 made of the metal silicide layer can be changed, and the number of electrons and holes can be increased to increase the internal potential. As a result, power generation efficiency can be improved. Such an effect is particularly effective for a photovoltaic power generation module having a Schottky structure.
Further, β-FeSi ₂ has a high band gap Eg of about 0.85 eV, and BaSi ₂ has a high band gap Eg of about 1.4 eV. Since it is a direct transition type, it has a high absorption efficiency for wavelengths of 1500 nm or less. . Β-FeSi ₂ and BaSi ₂ have an absorption coefficient of Si.
Is 100 to 1000 times higher than that of the Si solar cell layer.
It is also possible to reduce the thickness to about 100 to 1/1000.
The metal oxide layer 4 is preferably a SiO ₂ layer (silicon oxide layer). SiO
_{The two} layers have good adhesion to the β-FeSi ₂ layer or BaSi ₂ layer, and it is easy to obtain the effect of increasing the visceral potential. Moreover, it is preferable that the metal oxide layer 4 is 5 nm or less in thickness. If the thickness exceeds 5 nm, the metal oxide layer becomes an insulator, and electricity may not sufficiently flow to the electrode layer 3. Further, the thickness of the metal oxide layer is preferably 1 to 3 nm. Metal oxide layer thickness is 1nm
If the thickness is less than 1, sufficient effects may not be obtained.
The electrode layer 3 is preferably a metal silicide layer made of any one of NiSi _{2 and} CoSi. As the electrode layer 3, various materials such as a metal material can be applied as long as they have conductivity. On the other hand, NiSi ₂ or CoSi has good adhesion to a metal oxide film, particularly an SiO ₂ film. Therefore, the electricity generated by the semiconductor layer 2 can be taken out efficiently.

The semiconductor layer 2 made of a metal silicide layer made of one kind of β-FeSi ₂ or BaSi ₂ is preferably a polycrystalline metal silicide layer. As the metal silicide constituting the semiconductor layer 2, various materials such as single crystal and polycrystal can be applied. On the other hand, a single crystal has a cost burden because it is a manufacturing method using epitaxial growth. Polycrystalline metal silicide can be manufactured by a combination of a film forming method such as a sputtering method and a heat treatment, so that the cost can be reduced.
When the semiconductor layer 2 made of a metal silicide layer made of one kind of β-FeSi ₂ or BaSi _{2 is made} of polycrystalline metal silicide, the average crystal grain size of the polycrystalline metal silicide is 0.00.
It is preferably 01 μm or more (10 nm or more). If the average crystal grain size is less than 10 nm, the crystal size is too small, and the grain boundaries between the metal silicide crystal grains increase in the polycrystalline metal silicide layer (semiconductor layer 2). When the grain boundary increases, the grain boundary becomes a trap site, which may increase the internal resistance. The upper limit of the average crystal grain size of the polycrystalline metal silicide is not particularly limited, but the average crystal grain size is preferably 3 μm or less. Average crystal grain size is 3μm
If it is larger than 1, it may be difficult to produce a uniform crystal. The average crystal grain size is preferably 0.05 to 1.2 μm (50 to 1200 nm).

From the viewpoint of reducing the internal resistance, the thickness of the polycrystalline metal silicide layer is set to B
Preferably, A ≧ B, where A (μm) is the average crystal grain size of the polycrystalline metal silicide. By increasing the average crystal grain size A of the polycrystalline metal silicide layer from the thickness B of the polycrystalline metal silicide layer, the number of grain boundaries between the metal silicide crystal grains in the thickness direction of the polycrystalline metal silicide layer is reduced. Therefore, the internal resistance can be reduced. Reducing the number of grain boundaries can reduce the number of grain boundary trap sites.
FIG. 2 shows a schematic diagram of a polycrystalline metal silicide layer (semiconductor layer 2). In the figure, 2 is a polycrystalline metal silicide layer. B is the thickness of the metal silicide layer. FIG. 2 schematically shows a state in which five crystal grains are arranged. The grain boundary between crystal grains is not particularly limited, such as a straight line or a curved line. Further, as shown in FIG. 2, the individual particle diameters of the metal silicide crystal particles are the maximum diameters of the crystal particles appearing there, so that A1, A2, A3, A
4, A5 is the particle size. This operation is performed 30 grains, and the average value is obtained. Also,
In the measurement, an enlarged photograph of an arbitrary cross section in the thickness direction of the polycrystalline metal silicide layer (semiconductor layer 2) is measured. The maximum diameter of the individual crystal grains shown there is taken as the grain diameter, and the average value of any 30 grains is taken as the average crystal grain diameter A (μm). In addition, when not all 30 grains are included in one photograph (one field of view), a plurality of continuous enlarged photographs are used.
The film thickness of the metal silicide layer is preferably 1 μm or less. The film thickness is 1μ
If the thickness exceeds m, it may be difficult to form a metal silicide layer. 1μ
Even if it is thicker than m, there is a possibility that no more power generation efficiency can be obtained.
Β-FeSi ₂ has a carrier density of 1 × 10 ⁻¹⁴ to 1 × 10 ⁻¹⁸ cm ⁻³ , B
The carrier density of aSi ₂ is preferably 1 × 10 ⁻¹⁴ to 1 × 10 ⁻¹⁸ cm ⁻³ .

The photovoltaic power generation module of the first embodiment includes the electrode layer 3, the metal oxide layer 4, and the like as described above.
It has a laminated structure of a semiconductor layer 2 made of a metal silicide layer made of one kind of β-FeSi ₂ or BaSi ₂ . In this laminated structure, it is preferable that the metal oxide layer 4 is formed at 80% or more between the electrode layer 3 and the semiconductor layer 2. Further, it is most preferable that the metal oxide layer 4 is formed between the electrode layer 3 and the semiconductor layer 2 (100%).

Examples of the substrate 5 include a glass substrate, an insulating ceramic substrate, and a metal substrate.
In the case of a metal substrate, an insulating layer is provided to ensure insulation from the outside. The substrate 5 is used for holding the laminated structure.
Further, a surface electrode portion 6 is formed on the surface of the semiconductor layer 2 made of a metal silicide layer made of β-FeSi ₂ or BaSi ₂ . The surface electrode portion 6 has a wavelength of 1500 n.
It is preferable that the electrode material transmit light of m or less. Such materials include ITO
And transparent electrode materials such as ATO. Further, the surface electrode portion 6 may be formed at one or more places on the polycrystalline metal silicide layer 2. Moreover, an antireflection film or a glass substrate may be provided on the surface electrode portion 6 and the semiconductor layer 2 as necessary.
If it is the above 1st photovoltaic power generation module, a photovoltaic power generation module with sufficient power generation efficiency can be provided.

Here, the manufacturing method of a 1st photovoltaic power generation module is demonstrated. As long as it has the said structure regarding this embodiment, a manufacturing method will not be specifically limited, The following method is mentioned as a method for obtaining efficiently.
First, the substrate 5 is prepared. If necessary, the surface of the substrate 5 is cleaned. In the case of washing, a sufficient drying process is performed.
Next, the electrode layer 3 is formed. The electrode layer 3 is formed by using a film forming method such as a sputtering method for components constituting the electrode layer. The thickness of the electrode layer 3 is arbitrary, but is preferably 10 nm or more. Further, when a metal silicide such as NiSi ₂ is used as the electrode layer 3,
Examples thereof include a method using a NiSi ₂ target and a method using both a Ni target (metal target) and a Si target. In the case of the method using both the Ni target and the Si target, the Ni target and the Si target may be either simultaneous sputtering or alternate sputtering. Further, after the sputtering, it is preferable to react the NiSi ₂ by heat treatment. The heat treatment conditions are preferably 300 to 700 ° C. and 30 seconds to 5 minutes in an inert atmosphere such as nitrogen. If heat treatment is performed at a high temperature exceeding 700 ° C. or for a long time exceeding 5 minutes, the substrate 5 or the like may be distorted. The same method can be used when CoSi is formed as the electrode layer 3. NiSi ₂ and CoSi can be reacted even at 500 ° C. or lower.

Next, a patterning process is performed on the electrode layer 3 as necessary. The patterning process
There is a method of performing an etching process by applying an etching resist or placing a mask material at a place to be left as a pattern (wiring).
Next, a step of providing the metal oxide film 4 is performed. The method of forming the metal oxide film includes a method of oxidizing the surface of the electrode layer 3 as a first method, a method of sputtering a metal target in an oxygen-containing atmosphere as a second method, and a metal oxide target as a third method. There is a method of sputtering. Moreover, it is preferable to form the metal oxide layer 4 so that the film thickness is 5 nm or less.
Further, when a metal silicide such as NiSi ₂ or CoSi is used as the electrode layer 3, the first method (method of oxidizing the surface of the electrode layer 3) is effective. Examples of the method for oxidizing the surface of the electrode layer 3 include a method of exposing the surface of the electrode layer 3 to an oxygen-containing atmosphere, a method of spraying an oxygen-containing atmosphere, and a method of performing a heat treatment in an oxygen-containing atmosphere. NiSi ₂ and CoS
When the surface of the metal silicide layer such as i is oxidized, a SiO ₂ film is formed.
Next, a step of providing a metal silicide layer (semiconductor layer 2) is performed. When the metal silicide layer is provided, the metal silicide layer is formed using a film formation method such as a sputtering method. The thickness of the metal silicide layer is preferably 0.01 μm (10 nm) or more.
Further, when forming a β-FeSi ₂ layer, a method of sputtering an FeSi ₂ target,
A method using both an Fe target and a Si target is mentioned. In the case of the method using both the Fe target and the Si target, the Fe target and the Si target may be either simultaneous sputtering or alternate sputtering. Also, after sputtering, heat treatment is performed and Fe
It is preferable to react with Si2. As heat treatment conditions, in an inert atmosphere such as nitrogen, 3
00 to 900 ° C., 30 seconds to 1 hour is preferable. If heat treatment is performed at a high temperature exceeding 900 ° C. or for a long time exceeding 1 hour, the substrate 5 or the like may be distorted. When metal silicide (NiSi ₂ or CoSi) is used as the electrode layer 3, the heat treatment temperature can be set to 500 ° C. or less. This is because the metal silicide serves as a template for forming the β-FeSi ₂ layer. In particular, a template effect of metal silicide (NiSi ₂ or CoSi) is not lowered if the metal oxide film is thin as in the present embodiment. In addition, it is desirable that the heat treatment temperature for forming the β-FeSi ₂ layer be 500 ° C. or lower because damage to the substrate, particularly the glass substrate can be reduced. Further, the average crystal grain size of the β-FeSi ₂ layer can be controlled by heat treatment after sputtering.
Further, in order to obtain a homogeneous β-FeSi ₂ layer, a method of performing a heat treatment after alternately sputtering an Fe target and a Si target is preferable. Fe film 0.5 ~ 5nm, Si film 1 ~
A range of 10 nm is set, Fe film / Si film is set as one set, and laminated films are alternately formed until a target film thickness is obtained, and heat treatment is performed. Due to the heat treatment, the Fe film and the Si film react to produce polycrystalline β-
FeSi ₂ layer.

Similarly, when a BaSi ₂ layer is formed, a method of sputtering a barium silicide target can be used. Examples of the barium silicide target include a BaSi ₂ target and a BaSi target. In addition, heat treatment is performed after sputtering, and BaSi ₂
It is preferable to make it react. As heat treatment conditions, in an inert atmosphere such as nitrogen, 300 to
900 degreeC and 30 second-1 hour are preferable. If heat treatment is performed at a high temperature exceeding 900 ° C. or for a long time exceeding 1 hour, the substrate 5 or the like may be distorted.
When metal silicide (NiSi ₂ or CoSi) is used as the electrode layer 3, the heat treatment temperature can be set to 500 ° C. or less. This is because the metal silicide serves as a template for forming the BaSi ₂ layer. Further, it is desirable that the heat treatment temperature for forming the BaSi ₂ layer can be 500 ° C. or less because damage to the substrate, particularly the glass substrate can be reduced. Further, the average crystal grain size of the BaSi ₂ layer can be controlled by heat treatment after sputtering.
Moreover, when the patterning process of the electrode layer 3 is performed as described above, it is performed after a resist or a mask material is arranged in a place where the electrode layer 3 is not provided.
Further, in the case of a laminated structure such as a pn junction type, a step of doping impurities is performed.

As described above, a polycrystalline metal silicide layer is formed by combining sputtering and heat treatment. In order to control the average crystal grain size of the polycrystalline metal silicide layer, it is effective to grow the grains by applying heat treatment. This heat treatment is preferably 300 to 900 ° C. and 30 seconds to 1 hour. Further, this heat treatment may be performed together with the heat treatment after simultaneous sputtering or alternate sputtering of the Fe target and the Si target.
Further, if the Schottky structure is used, the heat treatment temperature can be set to 500 ° C. or lower, so that damage to the substrate 5 can be reduced.

Next, the process of providing the surface electrode part 6 is performed. The surface electrode portion is preferably formed by a sputtering method using an ITO target or an ATO target when a transparent electrode such as ITO or ATO is used. As shown in FIG. 1, when the surface electrode portion 6 is partially provided on the metal silicide layer 2, sputtering is performed with a resist or mask material disposed.
In addition, after the surface electrode portion 6 is formed, an antireflection film may be formed or bonded to a transparent substrate such as a glass substrate as necessary. Further, the surface electrode portion 6 may be bonded to a transparent substrate provided in advance.

Next, the photovoltaic power generation module (second photovoltaic power generation module) according to the second embodiment will be described. A schematic diagram of the second photovoltaic module is shown in FIG. FIG. 2 shows a structure in which a power storage mechanism 11 is provided on the back side of the substrate 5 of the first photovoltaic power generation module. In the figure, 6 is a photovoltaic power generation module according to the second embodiment, 2 is a polycrystalline metal silicide layer, 3
Are electrode layers, 4 is a surface electrode portion, 5 is a substrate, and 11 is a power storage mechanism portion.
The power storage mechanism 11 has a function of storing part or all of the power supplied from the polycrystalline metal silicide layer. Further, wiring (not shown) from the surface electrode portion 4 and the electrode layer 3
Are connected to the power storage mechanism 11.
FIG. 3 is a schematic view illustrating the power storage mechanism unit 11. In the figure, 6 is a power storage mechanism section, 12
And 13 are electrode parts, 14 is a sealing part, 15 is a power storage part, 16 is an electrolytic solution, 17 is a protective part, 18
Is the reducing part.
The power storage mechanism section 6 includes an electrode section 12 (corresponding to an example of a first electrode section), an electrode section 13 (second
The sealing part 14, the electrical storage part 15, the electrolyte solution 16, the protection part 17, and the reduction | restoration part 18 are provided.
The electrode portion 12 has a plate shape and is made of a conductive material. The electrode unit 12
For example, it can be formed from a metal such as aluminum, copper, stainless steel, or platinum. The electrode portion 13 has a plate shape and is provided to face the electrode portion 12. The electrode unit 13
It is made of a conductive material. The electrode part 13 can be formed from metals, such as aluminum, copper, stainless steel, platinum, for example. In this case, the electrode part 12 and the electrode part 1
3 can be formed from the same material, and the electrode portion 12 and the electrode portion 13 can be formed from different materials. Moreover, the electrode part 12 and the electrode part 13 are made of, for example, ITO, IZ
A conductive film made of O (Indium Zinc Oxide), FTO (Fluorine-doped Tin Oxide), SnO ₂ , InO ₃ or the like may be used.

Moreover, the electrode part 12 and the electrode part 13 are provided on a board | substrate (not shown). Examples of the substrate include a glass substrate and an insulated metal substrate. As this substrate, the aforementioned substrate 5 may be used. That is, a structure in which the power storage mechanism unit 6 is directly disposed on the substrate 5 may be taken.
Note that the electrode portion 13 on the side where the power storage unit 15 is provided serves as a negative electrode. Moreover, the electrode part 12 which opposes the electrode part 13 used as the negative electrode is a positive electrode. The sealing part 14 is provided between the electrode part 12 and the electrode part 13 and seals the peripheral part of the electrode part 12 and the peripheral part of the electrode part 13. In other words, the sealing portion 14 extends along the periphery of the electrode portion 12 and the electrode portion 13.
The inside of the electrical storage mechanism 6 is sealed by joining the electrode part 12 side and the electrode part 13 side. Further, the thickness of the sealing portion 14 is not particularly limited, but is preferably in the range of 1.5 to 30 times the thickness of the power storage portion 15. Since the thickness of the sealing portion 14 becomes a space for filling the electrolyte solution 16, it is preferable to have a predetermined range. If it is less than 1.5 times, the electricity stored in the electricity storage unit 15 is easily released, and if it exceeds 30 times, it is difficult to take out the electricity stored in the electricity storage unit 15.

The sealing part 14 shall contain a glass material. The sealing portion 14 can be formed using, for example, a glass frit that is made into a paste by mixing powder glass, a binder such as an acrylic resin, an organic solvent, or the like. Examples of the powder glass material include vanadate glass and bismuth oxide glass. In this case, the sealing portion 14 can be formed by applying paste-like glass frit to a portion to be sealed and firing it. And it can seal by melting the sealing part 14 by heating the sealing part 14. For example, sealing can be performed by irradiating the formed sealing portion 14 with laser light and melting a portion of the sealing portion 14 irradiated with the laser light. In addition, the sealing part 14 is not necessarily limited to what contains a glass material. For example, the sealing part 14 may include a resin material and be bonded between the electrode part 12 and the electrode part 13.
The power storage unit 15 is provided inside the sealing unit 14 and on the surface of the electrode unit 13 facing the electrode unit 12. The power storage unit 15 is provided on the electrode unit 13 via the protection unit 17.

The power storage unit 15 is formed of a material having a power storage property. The power storage unit 15 is, for example, a WO
3 (tungsten oxide).
The power storage unit 15 can have a porous structure. Moreover, it is preferable that the porosity of a porous structure is the range of 20-80 vol%. Moreover, the average particle diameter of 1-1000 nm
Furthermore, 1 to 100 nm tungsten oxide particles are preferable. In addition, a metal film or a metal oxide film may be provided on the surface of the tungsten oxide particles in order to improve power storage performance.
If the power storage unit 15 has a porous structure, the contact area with the electrolytic solution 16 can be increased. As a result, power storage in the power storage unit 15 can be facilitated.
The thickness dimension of the electrical storage part 15 can be about 30 micrometers, for example. For example, the power storage unit 15 may be formed by stacking WO3 particles having a diameter of about 20 nm to a thickness of about 30 μm. The thickness of the power storage unit 15 is not particularly limited as long as it has a power storage function, but is preferably 1 μm or more, and more preferably 1 μm to 100 μm.
Further, the electrolytic solution 16 is provided inside the sealing portion 14. That is, the electrolytic solution 16 is
The space defined by the electrode part 12, the electrode part 13, and the sealing part 14 is filled. The electrolytic solution 16 can be, for example, an electrolytic solution containing iodine. The electrolyte solution 16 can be obtained by, for example, dissolving lithium iodide and iodine in a solvent such as acetonitrile. Moreover, it is preferable that lithium iodide is in the range of 0.5 to 5 mol / L and iodine is in the range of 0.01 to 5 mol / L.

The protection unit 17 has a film shape and is provided between the power storage unit 15 and the electrode unit 13. The protection part 17 is provided so as to cover the surface of the electrode part 13 defined by the sealing part 14. The protection part 17 is provided in order to prevent the electrode part 13 from being corroded by the electrolytic solution 16.
Therefore, the protection part 17 is formed from a material having conductivity and chemical resistance against the electrolytic solution 16. The protection part 17 can be made of, for example, carbon or platinum. The thickness dimension of the protection part 17 can be about 100 nm, for example. In addition, when the electrode part 13 is formed from the material which has chemical resistance with respect to the electrolyte solution 16, the protection part 17 is used.
Is not necessarily provided.
The reducing unit 18 has a film shape and is provided to cover the surface of the electrode unit 12 defined by the sealing unit 14. The reducing unit 18 is provided to reduce ions contained in the electrolytic solution 16. For example, the reducing unit 18 reduces I ₃ ⁻ ions (triiodide ions) contained in the electrolytic solution 16 to I ⁻ ions (iodide ions). Therefore, the reducing part 18 is formed from a material that takes into consideration conductivity, chemical resistance to the electrolytic solution 16 and reduction of ions contained in the electrolytic solution 16. The reducing unit 18 can be formed of, for example, carbon or platinum. The thickness dimension of the reduction | restoration part 18 can be about 80 nm, for example.
With such a power storage mechanism unit, part or all of the power generation from the semiconductor layer 2 can be stored efficiently. Further, such a power storage mechanism unit has a power storage capacity of 1000 C / m ² or more,
Furthermore, it is also possible to set it as 10,000 C / m < ² > or more. Moreover, the electrical storage mechanism part 6 shall cover the outer periphery with an insulating member (not shown).

Next, the IV characteristic of a 2nd photovoltaic power generation module is demonstrated. FIG. 4 is a schematic graph for illustrating the IV characteristic of the second photovoltaic power generation module (second embodiment).
This will be described with reference to FIG. The vertical axis represents the voltage of power supplied by the solar power generation module 6, and the horizontal axis represents time. The photovoltaic power generation module 6 is exposed to sunlight and supplies a constant voltage. When the amount of sunlight decreases due to changes in the weather, etc., the power from the solar power generation module 6 decreases. At this time, when the voltage drops to a certain voltage (ΔV1), electric power is supplied from the power storage mechanism 6. Electric power is supplied according to the electric power (electric storage capacity) stored in the electric storage mechanism unit 6. It is assumed that switching to a commercial power source or the like is performed until the voltage from the power storage mechanism unit 6 drops to a constant voltage (ΔV2). Thus, unlike the case where power is generated by a solar cell alone, it is possible to improve the problem that the power supply becomes unstable as the amount of sunlight changes. Further, the power generation of the polycrystalline metal silicide layer 2 can be stabilized by increasing the power storage capacity of the power storage mechanism unit 6 to 1000 C / m ² or more. For example, the power generation efficiency target of the polycrystalline metal silicide layer 2 is 5
In the case of%, power generation can be stabilized by supplying electric power less than 5% from the power storage mechanism unit 6.

(Example)
(Examples 1 to 3, Comparative Example 1)
A NiSi ₂ layer (thickness 20 nm) was provided on the glass substrate as an electrode layer. NiSi
_Two layers were formed by alternately sputtering a Ni target and a Si target to form a laminated film in which a large number of Ni / Si layers were alternately laminated. Then, heat treatment is performed at 500 ° C. for 1 minute in a nitrogen atmosphere, and N
The iSi ₂ layer was reacted.
Next, a SiO ₂ layer was provided as a metal oxide layer on the NiSi ₂ layer surface. In providing the SiO ₂ layer, the surface of the NiSi ₂ layer is exposed to an oxygen-containing atmosphere so that the thickness of the SiO ₂ layer is 1 nm.
Example 1 was obtained by spraying an oxygen-containing atmosphere to make the SiO ₂ layer film thickness 3 nm, and Example 2 was subjected to heat treatment in the oxygen-containing atmosphere to make the SiO ₂ layer film thickness 5 nm. Example 3 was used, and Comparative Example 1 was used without the SiO2 layer.
Next, a β-FeSi ₂ layer (thickness 300 nm) was formed. The formation of the β-FeSi ₂ layer is
Fe targets and Si targets were alternately sputtered to form a laminated film in which a large number of Fe films / Si films were alternately laminated. Thereafter, heat treatment was performed at 450 ° C. to form a β-FeSi ₂ layer. Also,
The β-FeSi ₂ layer was a polycrystalline metal silicide layer having an average crystal grain size of 320 nm.
Example 1 A glass substrate provided with an ITO surface electrode part was laminated on a β-FeSi ₂ layer.
To 3 and Comparative Example 1 were produced. Each solar power generation module had a Schottky structure.
Regarding the photovoltaic power generation modules according to Examples 1 to 3 and Comparative Example 1, the power generation efficiency was obtained.
As a method for measuring the power generation efficiency, a solar simulator was used, and the power generation efficiency was obtained by irradiating light having an intensity of 1 kW / m ² having a spell of AM1.5. The results are shown in Table 1.

As can be seen from the table, the photovoltaic power generation module according to the example had good efficiency. This is Si
This is because the effect of increasing the internal potential of the semiconductor layer (β-FeSi ₂ layer) in which the O ₂ layer has a Schottky structure is obtained. Further, when Examples 1 to 3 are compared, Examples 1 to 1 are more preferable than Example 3.
2 had higher power generation efficiency. For this reason, it can be said that the SiO ₂ layer is preferably 1 to 3 nm.

(Examples 4 to 6, Comparative Example 2)
A NiSi ₂ layer (thickness 30 nm) was provided on a glass substrate. The NiSi ₂ layer was formed by alternately sputtering a Ni target and a Si target to form a laminated film in which a large number of Ni / Si layers were alternately laminated. Thereafter, the NiSi ₂ layer was reacted by heat treatment at 500 ° C. for 1 minute in a nitrogen atmosphere.
Next, a SiO ₂ layer was provided as a metal oxide layer on the NiSi ₂ layer surface. In providing the SiO ₂ layer, the surface of the NiSi ₂ layer is exposed to an oxygen-containing atmosphere so that the thickness of the SiO ₂ layer is 1 nm.
Example 4 was obtained by spraying an oxygen-containing atmosphere to form a SiO ₂ layer with a thickness of 3 nm. Example 5 was subjected to heat treatment in an oxygen-containing atmosphere to obtain a SiO ₂ layer with a thickness of 5 nm. Example 6 was used, and Comparative Example 2 was used without the SiO ₂ layer.
Next, a BaSi ₂ layer (thickness 250 nm) was formed. The formation of the BaSi ₂ layer is based on the BaSi
The target was sputtered and then heat treated at 460 ° C. to form a BaSi ₂ layer. The BaSi ₂ layer was a polycrystalline metal silicide layer having an average crystal grain size of 270 nm.
A glass substrate provided with an ITO surface electrode part on a BaSi ₂ layer was laminated to Examples 4 to 6
And the photovoltaic power generation module which concerns on the comparative example 2 was produced. Each solar power generation module had a Schottky structure.
Regarding the photovoltaic power generation modules according to Examples 4 to 6 and Comparative Example 2, the power generation efficiency was obtained.
The method for measuring the power generation efficiency is the same as that in Example 1. The results are shown in Table 2.

As can be seen from the table, the photovoltaic power generation module according to the example had good efficiency. This is Si
This is because an effect of increasing the internal potential of the semiconductor layer (BaSi ₂ layer) in which the O ₂ layer has a Schottky structure is obtained. Moreover, when Examples 4-6 were compared, the power generation efficiency of Examples 4-5 was higher than Example 6. For this reason, it can be said that the SiO ₂ layer is preferably 1 to 3 nm.

(Examples 7 to 10)
A NiSi ₂ layer (thickness 30 nm) was provided on a glass substrate. The NiSi ₂ layer was formed by alternately sputtering a Ni target and a Si target to form a laminated film in which a large number of Ni / Si layers were alternately laminated. Thereafter, the NiSi ₂ layer was reacted by heat treatment at 500 ° C. for 1 minute in a nitrogen atmosphere.
Next, the NiSi ₂ layer surface was oxidized to form a 2 nm thick SiO 2 film. Furthermore, β-
A FeSi ₂ layer was formed. The film thickness of the β-FeSi ₂ layer is as shown in Table 3. Β
-FeSi ₂ layer was formed by alternately sputtering an Fe target and a Si target to form a laminated film in which a large number of Fe films / Si films were alternately laminated. Subsequently, the mixture was allowed to react in the beta-FeSi ₂ layer by a heat treatment at 400 to 450 ° C.. The average crystal grain size is as shown in Table 3.
Example 7 A glass substrate provided with an ITO surface electrode portion was laminated on a β-FeSi ₂ layer.
To 10 solar power generation modules. Each solar power generation module had a Schottky structure.
Regarding the solar power generation modules according to Examples 7 to 10 and Comparative Example 1, the power generation efficiency was obtained. The method for measuring the power generation efficiency is the same as that in Example 1. The results are shown in Table 3.

As can be seen from the table, the photovoltaic power generation module according to the example had good efficiency. This is Si
This is because the effect of increasing the internal potential of the semiconductor layer (β-FeSi ₂ layer) in which the O ₂ layer has a Schottky structure is obtained. Further, Example 10 in which the β-FeSi ₂ layer exceeded 1 μm (1.
5 μm), no improvement in power generation efficiency was observed. Therefore, the thickness of the β-FeSi ₂ layer is 1
It can be seen that the thickness is preferably μm or less.

(Examples 1A, 2A)
Example 1A, Example 2 in which the power storage mechanism unit illustrated in FIG. 3 is joined to the back surface of the substrate of the photovoltaic module according to Examples 1 to 2 and the power storage mechanism unit is provided on the back surface of Example 1. Example 2A was provided with a power storage mechanism part on the back surface. When the IV characteristics were examined, the behavior shown in FIG. 4 was shown. For this reason, it turns out that the photovoltaic power generation module which concerns on Example 1A and Example 2A is strong in the change of the amount of sunlight.
In addition, regarding Examples 2 to 10, the IV characteristics showed behavior as shown in FIG. 4 by unitizing with the power storage mechanism.

As mentioned above, although several embodiment of this invention was illustrated, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and without departing from the spirit of the invention,
Various omissions, replacements, changes, etc. can be made. These embodiments and their variations are
The invention is included in the scope and gist of the invention, and is included in the invention described in the claims and the equivalent scope thereof. Further, the above-described embodiments can be implemented in combination with each other.

DESCRIPTION OF SYMBOLS 1 ... Solar power generation module 2 which concerns on 1st embodiment ... Metal silicide layer 3 ... Electrode layer 4 ... Surface electrode part 5 ... Substrate 6 ... Solar power generation module 11 which concerns on 2nd embodiment ... Power storage mechanism part 12 ... Electrode part 13 ... Electrode part 14 ... Sealing part 15 ... Power storage part 16 ... Electrolytic solution 17 ... Protection part 18 ... Reduction part

Claims (9)

A photovoltaic power generation module comprising a stacked structure of an electrode layer, a metal oxide layer, and a semiconductor layer made of a metal silicide layer made of β-FeSi ₂ or BaSi ₂ . The photovoltaic module according to claim 1, wherein the metal oxide layer is a SiO ₂ layer. The photovoltaic module according to claim 1, wherein the metal oxide layer has a thickness of 5 nm or less. The photovoltaic power generation module according to any one of claims 1 to 3, wherein the photovoltaic power generation module is a Schottky type. Electrode layer, photovoltaic module according to any one of claims 1 to 4, characterized in that it consists of one type of NiSi ₂ or CoSi. The photovoltaic module according to any one of claims 1 to 5, wherein the semiconductor layer made of the metal silicide layer is a polycrystalline metal silicide layer. The photovoltaic module according to any one of claims 1 to 6, wherein the semiconductor layer made of the metal silicide layer has a thickness of 1 µm or less. The photovoltaic module according to any one of claims 1 to 7, further comprising a power storage mechanism unit that stores part or all of the power supplied from the semiconductor layer formed of the metal silicide layer. . The photovoltaic power generation module according to claim 8, wherein the power storage mechanism unit includes tungsten oxide particles.

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