JPH11224953A - Photovolatic device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the orintatioal property of the light absorption layer of a photovoltic device and moreover, to manufacture the device into such a structure that the device has a high photoelectric conversion efficiently, which is superior in thermal stability, by a method wherein the device has the specified light absorption layer and a conductive layer, which is formed on an opposite side to the side of incident light in contact with the light absorption layer, and the conductive layer is formed of an amorphous alloy layer. SOLUTION: A photovoltaic device is provided with a substrate 1, a conductive layer 2 consisting of an amorphous alloy layer, a light absorption layer 3 consisting of a I-III-VI2 compound semiconductor layer, a semiconductor layer 4 of conductivity type reverse to that of the layer 3 and a transparent elected layer 5. It is preferable that the crystallization temperature of the amorphous alloy layer be 400 deg.C or higher, in consideration of the heating temperature at the time when the layer 3 is formed on the layer 2 consisting of the amorphous alloy layer. The amorphous alloy layer is constituted of at least one layer, which is chosen from among a group of layers consisting of a transition metal including Fe, Co, Ni, Cr, Cu and Pd and its solid solution, and at least one layer, which is chosen from among a group of layers consisting of elements including B. C, Si, P, Ge, Ti, Zr, Hf, Nb and Ta and its solid solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic device having high photoelectric conversion efficiency and a method for manufacturing the same.

[0002]

2. Description of the Related Art I-II having a chalcopyrite structure
A photovoltaic device using an I-VI Group ₂ compound semiconductor as a light absorbing layer shows high photoelectric conversion efficiency even when the light absorbing layer is a thin film, and has little deterioration in efficiency due to light irradiation, so that it can be put to practical use. Expected. As a method for forming the light absorbing layer, a multi-source simultaneous vapor deposition method for simultaneously evaporating each element constituting the I-III-VI Group ₂ compound semiconductor from a separate evaporation source to obtain a compound on a substrate, A gas phase selenization (sulfide) method of heating a laminated film or a mixed film of constituent metals in an atmosphere containing a chalcogen element is known. In particular, the latter method has attracted attention as a method suitable for mass production because it can be mass-produced in a large area. Conventionally, I-III-VI ₂ group compound semiconductor having a chalcopyrite structure is a light-absorbing layer has been formed on or in the metal substrate a metal thin film using a method described above. In this case, the formed I
The III-VI group ₂ compound semiconductor is in contact with the light absorbing layer and the light absorbing layer and is formed on the light incident side of the light absorbing layer due to the influence of the base metal and causing a problem in the orientation. Due to lattice mismatch with the buffer layer), problems such as a decrease in photoelectric conversion efficiency have occurred.

In order to solve this problem, Japanese Patent Application Laid-Open No. 4-199
No. 880 discloses that the orientation of a chalcopyrite thin film is improved by using an amorphous conductive substrate or an amorphous conductive thin film as a base of the chalcopyrite thin film. JP-A-4-309238 discloses that the surface of a conductive substrate is made amorphous by ion implantation or the like, and a chalcopyrite thin film is formed thereon, thereby improving the orientation of the chalcopyrite thin film. Is disclosed. However, in these methods, since an amorphous material is used as a base, problems such as inferior thermal stability and a change with time occur, and when using a method such as ion implantation, a special device is used. , There have been problems such as an increase in production cost and a decrease in production efficiency. In particular, when the thermal stability is inferior, crystallization occurs when the chalcopyrite thin film as the light absorbing layer is formed, which has a problem such as adversely affecting the orientation of the chalcopyrite thin film. In a photovoltaic device such as a solar cell using a chalcopyrite thin film formed on a base as described above, there have been problems such as a decrease in photoelectric conversion efficiency.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such a problem, improve the orientation of the light absorbing layer, and further improve the thermal stability and the photovoltaic efficiency with high photoelectric conversion efficiency. It is to provide a power device. Another object of the present invention is to provide a method for manufacturing a photovoltaic device having high photoelectric conversion efficiency, which can be obtained at low cost, and which is excellent in productivity.

[0005]

According to SUMMARY OF THE INVENTION The present invention, first, formed on the opposite side of the light incident side in contact with the light absorbing layer and the light-absorbing layer comprising a I-III-VI ₂ group compound semiconductor A photovoltaic device having a conductive layer provided, wherein the conductive layer is made of an amorphous alloy.

Second, in a photovoltaic device having a light absorbing layer made of a group I-III-VI group ₂ compound semiconductor and a conductive layer formed in contact with the light absorbing layer and on the side opposite to the light incident side, A photovoltaic device is provided, wherein the conductive layer is an amorphous alloy ribbon also serving as a substrate.

Third, in the photovoltaic device according to the first or second aspect, the crystallization temperature of the amorphous alloy is 400 ° C.
A photovoltaic device characterized by the above is provided.

Fourthly, in the photovoltaic device according to any one of the first to third aspects, the amorphous alloy is made of Fe, C
o, at least one selected from the group consisting of transition metals containing 1 to 6 kinds of Ni, Cr, Cu, and Pd and solid solutions thereof, and B, C, Si, P, Ge, Ti, Zr, Hf, and N
b, a photovoltaic device characterized by comprising at least one element selected from the group consisting of an element containing 1 to 10 kinds of Ta and a solid solution thereof.

Fifth, in the photovoltaic device according to any one of the first to fourth aspects, the sheet resistance of the conductive layer is 5
Provided is a photovoltaic device characterized by being 0 Ω / □ or less.

Sixth, in the photovoltaic device according to any one of the first to fifth aspects, a semiconductor material layer having a larger band gap than the light absorbing layer is provided on the light incident side in contact with the light absorbing layer. There is provided a photovoltaic device comprising:

Seventh, in the photovoltaic device according to the sixth aspect, the semiconductor material layer includes a semiconductor layer bonded to the light absorbing layer, and a transparent electrode formed on the light incident side in contact with the semiconductor layer. A photovoltaic device is provided, comprising:

Eighth, in the photovoltaic device according to the sixth or seventh aspect, the semiconductor material layer to be bonded to the light absorbing layer is selected from at least a group consisting of ZnS, ZnSe, ZnO, and a mixed crystal thereof. A photovoltaic device characterized by comprising the following.

[0013] Ninth, method for manufacturing a photovoltaic device having a I-III-VI ₂ group conductive layer formed on the opposite side of the light incident side in contact with the light absorbing layer and a light absorbing layer made of a compound semiconductor , Wherein a light absorbing layer is formed on a conductive layer made of an amorphous alloy by heating a layer containing a group I element and a group III element in an atmosphere containing at least a group VI element. Is provided.

Tenth, manufacturing of a photovoltaic device having a light absorbing layer made of a Group I-III-VI Group ₂ compound semiconductor and a conductive layer formed in contact with the light absorbing layer and on the side opposite to the light incident side. In the method, I-III-
Method for manufacturing a photovoltaic device, characterized by continuously forming a light absorbing layer made of VI ₂ group compound semiconductor is provided.

[0015] Eleventh, the photovoltaic device having a light-absorbing layer and the light-absorbing layer on a conductive layer formed on the opposite side of the light incident side in contact consisting of I-III-VI ₂ group compound semiconductor In the manufacturing method, I-III is formed on an amorphous alloy ribbon.
Light absorbing layer made of -VI ₂ group compound semiconductor, a semiconductor layer bonded to the light absorbing layer, and a method for manufacturing a photovoltaic device, characterized by continuously forming a transparent electrode layer in contact with said semiconductor layer Provided.

Hereinafter, the present invention will be described in more detail. The first photovoltaic device according to the light having a light-absorbing layer and the light-absorbing layer on a conductive layer formed on the opposite side of the light incident side in contact consisting of I-III-VI ₂ group compound semiconductor In the electromotive force device, the conductive layer is made of an amorphous alloy. By using an amorphous alloy for the conductive layer, the influence of the underlayer on the orientation of the light absorbing layer can be reduced, and the I-I formed on the conductive layer can be reduced.
The thin film of the II-VI group ₂ compound is placed on its densest surface (11
2) It can be oriented on the plane. Thereby, I-I
Crystal defects in the light absorption layer made of the II-VI group ₂ compound semiconductor are reduced and the diffusion length of the photocarrier is increased, so that high photoelectric conversion efficiency is obtained.

[0017] Generally the crystal orientation of the thin film is known to be strongly affected by the underlying, to orient I-III-VI ₂ group compounds thin film (112) on the surface, the underlying layer is light-absorbing It is desirable not to affect the orientation of the layer. Therefore, the underlayer is preferably made of an amorphous alloy. In addition, by appropriately using an amorphous alloy as the underlayer of the light absorbing layer, thermal stability is improved and high photoelectric conversion efficiency can always be obtained.

The photovoltaic device according to the second aspect has a II
The conductive layer formed on the side opposite to the light incident side in contact with the light absorbing layer made of the II-VI group ₂ compound semiconductor is an amorphous alloy ribbon also serving as a base. Thereby, in addition to obtaining a photovoltaic device having high photoelectric conversion efficiency, by using a continuous thin strip made of an amorphous alloy as the conductive layer, it also serves as a base,
The constituent materials of the photovoltaic device can be reduced, and the photovoltaic device can be manufactured continuously, so that the cost and the productivity of the photovoltaic device can be reduced.

The photovoltaic device according to the third aspect is characterized in that the crystallization temperature of the amorphous alloy is 400 ° C. or higher. In this manner, when the light absorbing layer is formed on the conductive layer made of the amorphous alloy, crystallization of the amorphous alloy can be suppressed, whereby the (112) plane of the light absorbing layer can be suppressed. The orientation is improved, and high photoelectric conversion efficiency can be obtained. Further, when an amorphous alloy ribbon serving also as a base is used as the conductive layer, a decrease in mechanical strength of the ribbon due to crystallization of the amorphous alloy can be suppressed.

In the photovoltaic device according to the fourth aspect, the amorphous alloy may be one of Fe, Co, Ni, Cr, Cu, and Pd.
At least one selected from the group consisting of transition metals containing six types and solid solutions thereof, and B, C, Si, P, Ge, T
It is characterized by comprising at least one element selected from the group consisting of elements including 1 to 10 kinds of i, Zr, Hf, Nb and Ta and solid solutions thereof.
Thus, an amorphous alloy layer having thermal stability and little change over time can be formed, and a high photoelectric conversion efficiency can always be obtained by forming a light absorbing layer thereon. Further, when an amorphous alloy ribbon serving also as a substrate is used as the conductive layer, an amorphous alloy ribbon having sufficient mechanical strength can be obtained.

The photovoltaic device according to the fifth aspect is characterized in that the sheet resistance of the conductive layer is 50 Ω / □ or less. By adopting such a conductive layer, a series resistance component is reduced, so that photocarriers can be effectively collected, so that high photoelectric conversion efficiency can be obtained.

The photovoltaic device according to the sixth aspect is characterized in that a semiconductor material layer having a larger band gap than the light absorbing layer is provided in contact with the light absorbing layer and on the light incident side of the layer. It is assumed that. By providing such a semiconductor material layer, the short-wavelength sensitivity is improved and a high photoelectric conversion efficiency can be obtained by a so-called window effect as compared with the case of the homojunction.

In the photovoltaic device according to the seventh aspect, the semiconductor material layer having a band gap larger than that of the light absorption layer is formed on the semiconductor layer to be joined to the light absorption layer and on the light incident side in contact with the semiconductor layer. And a transparent electrode layer formed. This makes it possible to form an ideal bonding interface and suppress surface recombination, improve the bonding characteristics between the light absorbing layer and the layer in contact therewith, and obtain high photoelectric conversion efficiency.

[0024] In the photovoltaic device according to the eighth aspect, the semiconductor material layer to be bonded to the light absorbing layer is formed of at least ZnS or ZnS.
It is characterized by comprising a material selected from the group consisting of Se, ZnO and a mixed crystal thereof. Each of the above materials has a band gap of 2.
6 eV or more, a large window effect can be expected, and by selecting an appropriate mixed crystal ratio, I-III-
It is possible to reduce the lattice mismatch between the VI ₂ group compound semiconductor, good bonding properties. Furthermore,
It is also desirable in that it does not contain harmful substances such as Cd in CdS which has been conventionally used.

[0025] In the method for manufacturing a photovoltaic device according to the ninth aspect, the layer containing Group I and Group III elements may have at least VI
The light absorbing layer is formed on a conductive layer made of an amorphous alloy by heating in an atmosphere containing a group element. By forming the light absorbing layer in this manner, adhesion to the conductive layer (including the amorphous alloy ribbon also serving as the base), crystallinity and conductivity controllability are ensured,
The light absorbing layer having a large area can be manufactured in large quantities, and the manufacturing cost of the photovoltaic device can be reduced.

The method for manufacturing a photovoltaic device according to the tenth aspect is
Which is characterized in that continuously forming a light absorbing layer made of I-III-VI ₂ group compound semiconductor on the amorphous alloy ribbon, it thereby making a photovoltaic device continuously And the productivity of the photovoltaic device can be improved.

The method for manufacturing a photovoltaic device according to the eleventh, the semiconductor layer to be bonded onto an amorphous alloy ribbon light absorbing layer consisting of I-III-VI ₂ group compound semiconductor, the light-absorbing layer and And a transparent electrode layer in contact with the semiconductor layer is continuously formed, whereby the photovoltaic device can be manufactured continuously, and the productivity of the photovoltaic device is improved. Can be done.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view schematically showing an example of a photovoltaic device according to the present invention, in which a substrate 1, a conductive layer 2 made of an amorphous alloy, and a light absorbing layer 3 made of an I-III-VI group ₂ compound semiconductor are shown. , A semiconductor layer 4 having a conductivity type opposite to that of the light absorption layer 3 and a transparent electrode layer 5. Also,
FIG. 2 is a cross-sectional view schematically showing another example of the photovoltaic device of the present invention, and is a thin amorphous alloy ribbon (also serving as a base and a conductive layer).
2A, and a I-III-VI ₂ group compound light absorbing layer 3 made of a semiconductor, the semiconductor layer 4 and the transparent electrode layer 5 is a light-absorbing layer 3 and the opposite conductivity type.

The crystallization temperature of the amorphous alloy is determined by setting the light absorbing layer on the conductive layer 2 made of the amorphous alloy or the amorphous alloy ribbon 2A.
In consideration of the heating temperature when forming the upper layer, the temperature is preferably 400 ° C. or higher, and particularly preferably 500 ° C. or higher. This can prevent crystallization of the amorphous alloy when forming the light absorption layer made of the I-III-VI group ₂ compound semiconductor on the conductive layer or on the amorphous alloy ribbon.

As an amorphous alloy, ease of non-crystallization,
From the viewpoints of crystallization temperature, degree of change over time, characteristics as a conductive layer, and mechanical strength when formed into a ribbon, a transition metal-nonmetal system, a transition metal-transition metal system, a typical metal-typical metal system, etc. There are various types, such as Fe, Co, N
i, at least one selected from the group consisting of a transition metal containing 1 to 6 kinds of Cr, Cu, and Pd and a solid solution thereof;
B, C, Si, P, Ge, Ti, Zr, Hf, Nb, T
It is preferable to be constituted by at least one element selected from the group consisting of an element containing 1 to 10 kinds of a and a solid solution thereof.

Various methods such as a liquid phase coagulation control method, a gas phase coagulation control method, a solid phase reaction control method, a precipitation control method in a solution, and a bulk processing method can be used for producing an amorphous alloy layer or ribbon. Yes, any method may be used. In the case of an amorphous alloy ribbon, considering the photovoltaic device manufacturing process,
It is necessary to have mechanical strength and toughness.

The sheet resistance of the conductive layer 2 made of an amorphous alloy or the amorphous alloy ribbon 2A is preferably 50 Ω / □ or less, more preferably 10 Ω / □ or less. As a result, optical carriers can be effectively collected, so that high photoelectric conversion efficiency can be obtained. Here, the sheet resistance value varies depending on the relationship between the electrical resistivity and the film thickness. However, in consideration of the material cost, residual stress, and the like, it is desirable that the film thickness of the conductive layer 2 be within about 10 μm. From this, the electric resistivity of the conductive layer material is preferably 5 × 10 ⁻² Ωcm or less, particularly 1 × 10 ⁻² Ωcm.
^-2 Ωcm or less is preferable.

In the case of the amorphous alloy ribbon 2A, the film thickness of the amorphous alloy ribbon 2A should be within about 100 μm in consideration of the material cost, residual stress, mechanical strength, and the like. desirable. From this, the electrical resistivity of the amorphous alloy ribbon (which also serves as the base and the conductive layer) is 5 × 1
It is preferably 0 ^-1 Ωcm or less, particularly preferably 1 × 10 ^-1 Ωcm or less.

[0034] Subsequently, the light absorbing layer 3 made of I-III-VI ₂ group compound semiconductor on the conductive layer 2 or on the amorphous alloy thin strip 2A, the multi-source coevaporation, normal or reduced pressure vapor sulfide (Selenization) method or the like. In the multi-source simultaneous vapor deposition method, the group I, group III, and group VI elements are simultaneously evaporated from separate evaporation sources, and are deposited on a substrate having a conductive layer 2 disposed thereon (heated to 300 to 500 ° C.) or in an amorphous state. In this method, a compound having a desired composition is obtained on the thin alloy ribbon 2A (heated to 300 to 500 ° C.). In this case, it is necessary to strictly control the evaporation rate of each element.

The gas-phase sulfurization (selenization) method comprises a group I and
After forming a laminated film or a mixed film made of a group II element on a substrate having the conductive layer 2 or on the amorphous alloy ribbon 2A by a vacuum deposition method, a sputtering method, or the like, S or S
atmosphere containing e, for example, H ₂ S or H ₂ Se gas diluted with an inert gas 400 at (normal pressure or reduced pressure)
This is a method of obtaining a compound by heating to 600 ° C., and this method is preferable in that the area of the light absorption layer can be increased and mass production can be easily performed. The appropriate thickness of the light absorption layer 3 made of the I-III-VI group ₂ compound semiconductor is 0.5 to 5 μm.

Elements constituting the I-III-VI ₂ compound semiconductor include Cu, Ag, and II as Group I elements.
In, Ga, Al as Group I element, S as Group VI element
It is appropriate to select one or more types each from e and S.

A semiconductor material layer (a semiconductor material layer having a conductivity type opposite to that of the light absorption layer) provided in contact with the light absorption layer made of the I-III-VI group ₂ compound semiconductor and on the light incident side of the layer.
As a material for (1), the same compound semiconductor as the I-III-VI group ₂ compound semiconductor can be used (homojunction), but a semiconductor having a larger band gap can be used to reduce light in a short wavelength region by a window effect. It is desirable from the viewpoint that more light can be taken into the light absorbing layer, that is, from the viewpoint of improving short-wavelength sensitivity. Further, the semiconductor material layer is formed as a laminate of a semiconductor layer (semiconductor layer having a conductivity type opposite to that of the light absorption layer) 4 and a transparent electrode layer (for example, a degenerated n-type semiconductor layer) 5 thereon. This is desirable from the viewpoint of improving the characteristics.

The semiconductor layer 4 is formed, for example, by a solution growth method, MOC
The transparent electrode layer 5 is formed by depositing ZnSe, ZnS, ZnO or a mixed crystal thereof to a film thickness of 10 to 200 nm by a VD method or the like. By IT
It can be formed by depositing O, ZnO: Al or the like to a thickness of 0.1 to 2 μm.

[0039]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 A 1 μm-thick Fe _4.5 Ni film was formed as a conductive layer on a glass substrate.
_2.3 Co ₆₆ Nb _2.2 Si ₁₀ B ₁₅ was deposited by a sputtering method using a composite target. As a result of X-ray diffraction and electron beam diffraction measurements, this conductive layer was confirmed to be amorphous. The above-mentioned conductive layer was heated on a heating stage in an electron microscope, and the crystallization temperature was measured in-situ.

Next, using a Cu target and an In target, a Cu / I
n laminated film is deposited, and this is reduced in pressure H ₂ S diluted with Ar.
By heating to 400 ° C. in a gas, a 2 μm-thick p-type I-III-VI group ₂ compound semiconductor (CuInS ₂ )
Was formed. As a result of X-ray diffraction, the light absorption layer made of CuInS ₂ was preferentially oriented to the (112) plane, but diffraction lines from other planes were also observed. The intensity ratio to the diffraction line from the (204) plane, which had the second highest intensity, was 28.0, indicating that the orientation was extremely strong.

Next, a 100 nm-thick ZnO-ZnS mixed crystal film as an n-type semiconductor layer was formed on the light absorbing layer made of a p-type I-III-VI group ₂ compound semiconductor (CuInS ₂ ) by MOCVD. Deposited. Subsequently, a 500 nm-thick ITO film was deposited as a transparent electrode layer by a sputtering method to obtain a photovoltaic device. The photoelectric conversion efficiency of this photovoltaic device is 11.2% (AM1.5, 100 mW /
cm ² ).

Comparative Example 1 A p-type I-III- was formed on a conductive layer in the same manner as in Example 1 except that a 1 μm-thick Mo (crystal layer) was formed as a conductive layer.
A light absorption layer made of a VI ₂ group compound semiconductor (CuInS ₂ ) was formed. The light absorbing layer made of CuInS ₂ is X
As a result of the line diffraction, it was preferentially oriented to the (112) plane, but diffraction lines from other planes were also observed. The intensity ratio with the diffraction line from the (204) plane, which has the second highest intensity, is
It was 5.2, which was much smaller than that of Example 1, indicating that the orientation was weak. Next, n is formed on the light absorption layer made of a p-type I-III-VI ₂ group compound semiconductor (CuInS ₂ ).
As a type semiconductor layer, a ZnO-ZnS mixed crystal film having a thickness of 100 nm was deposited by MOCVD. Subsequently, a 500 nm-thick ITO film was deposited as a transparent electrode layer by a sputtering method to obtain a photovoltaic device. The photoelectric conversion efficiency of this photovoltaic device is 8.8% (AM 1.5, 100 m
W / cm ² ), which is about 27% lower than the photoelectric conversion efficiency of the photovoltaic device of Example 1.

Example 2 As an amorphous alloy ribbon, Fe ₆₃ Ni ₁₆ was prepared by a liquid quenching method.
A Si ₈ B ₁₄ ribbon (thickness: 30 μm) was prepared. As a result of X-ray diffraction and electron diffraction measurements, it was confirmed that the ribbon was amorphous. The amorphous alloy ribbon was heated on a heating stage in an electron microscope, and the crystallization temperature was measured in-situ. Next, a Cu / In laminated film is deposited on the ribbon by a sputtering method using a Cu target and an In target, and is heated to 400 ° C. in a reduced pressure H ₂ S gas diluted with Ar. Then, a light absorption layer made of a p-type I-III-VI ₂ group compound (CuInS ₂ ) layer having a thickness of 2 μm was formed.

Next, a 100 nm-thick ZnO—ZnS mixed crystal film was formed on the light absorption layer as an n-type semiconductor layer by MO.
A photovoltaic device was obtained by depositing using a CVD method and subsequently depositing an ITO film having a thickness of 500 nm as a transparent electrode layer using a sputtering method. The photoelectric conversion efficiency of this photovoltaic device is 11.2% (AM1.5, 100 mW / cm
² ).

During the fabrication of this photovoltaic device, the above-mentioned light absorbing layer, n-type semiconductor layer and transparent electrode layer were continuously formed on the amorphous alloy ribbon. In Comparative Example 1, the sample was exchanged for each layer, the device was evacuated, and each layer was formed as usual. However, in comparison with this case, each layer was continuously formed on the amorphous alloy ribbon. In this case, the productivity of the photovoltaic device was improved, and the photovoltaic device could be manufactured about 10 times in a unit time.

Example 3 A 1 μm-thick Fe ₇₈ Si ₁₀ film was formed as a conductive layer on a glass substrate.
The B ₁₂ was deposited by a sputtering method using a composite target. As a result of X-ray diffraction and electron beam diffraction measurements, this conductive layer was confirmed to be amorphous. In addition, as a result of measuring the crystallization temperature in the same manner as in Example 1, the crystallization temperature was 4
80 ° C. Next, using a Cu target and an In target, Cu is deposited on the conductive layer by a sputtering method.
/ In is deposited and reduced pressure H diluted with Ar
By heating to 400 ° C in ₂ S gas, the film thickness becomes 2μ.
m p-type I-III-VI group ₂ compound semiconductor (CuIn
A light absorbing layer made of S ₂ ) was formed.

Next, a 100 nm-thick ZnO-ZnS mixed crystal film as a n-type semiconductor layer was formed on the light absorbing layer made of a p-type I-III-VI group ₂ compound semiconductor (CuInS ₂ ) by MOCVD. Deposited. Subsequently, a 500 nm-thick ITO film was deposited as a transparent electrode layer by a sputtering method to obtain a photovoltaic device. The photoelectric conversion efficiency of this photovoltaic device is 11.0 to 11.5% (AM 1.5, 1
00 mW / cm ² ). In the production of this photovoltaic device, the samples in each layer were exchanged, the device was evacuated, and the layers were formed as usual.

Example 4 As an amorphous alloy ribbon, Fe ₇₈ Si _{10 was formed} by a liquid quenching method.
B ₁₂ ribbons (film thickness 30μm) were prepared. As a result of X-ray diffraction and electron diffraction measurements, it was confirmed that the ribbon was amorphous. As a result of measuring the crystallization temperature in the same manner as in Example 2, the crystallization temperature of the ribbon was 480 ° C.
Then, on the book band using Cu target and In targets, to deposit a laminated film of Cu / In by sputtering, which under reduced H ₂ S gas diluted with Ar 40
By heating to 0 ° C., a 2 μm-thick p-type I-II
A light absorbing layer composed of an I-VI ₂ group compound (CuInS ₂ ) layer was formed.

Next, a 100 nm-thick ZnO—ZnS mixed crystal film was formed on the light absorbing layer as an n-type semiconductor layer by MO.
A photovoltaic device was obtained by depositing using a CVD method and subsequently depositing an ITO film having a thickness of 500 nm as a transparent electrode layer using a sputtering method. The photoelectric conversion efficiency of this photovoltaic device is 11.0 to 11.5% (AM 1.5, 100
mW / cm ² ). During the production of this photovoltaic device, the above-mentioned light absorbing layer, n-type semiconductor layer and transparent electrode layer were continuously formed on the amorphous alloy ribbon. In this case, the productivity of the photovoltaic device was improved as compared with the case of Example 3 described above, and a photovoltaic device approximately 10 times as large as the unit time could be manufactured.

Example 5 As an amorphous alloy ribbon, Fe produced by a liquid quenching method was used.
₈₆ B ₁₄ p-type I-III-VI ₂ group except for using the ribbons in the same manner as in Example 2 on the thin strip compound semiconductor (CuIn
A light absorbing layer made of S ₂ ) was formed. As a result of X-ray diffraction and electron beam diffraction measurements, it was confirmed that the ribbon was amorphous. The crystallization temperature was measured in the same manner as in Example 2. As a result, the crystallization temperature of the ribbon was 340 ° C. Further, as a result of X-ray diffraction, the light absorption layer made of CuInS ₂ was preferentially oriented to the (112) plane.
The intensity ratio with respect to the diffraction line from the (04) plane was 6.5, which was smaller than that of Example 1 and the orientation was weak.

Next, a 100 nm-thick ZnO-ZnS mixed crystal film as an n-type semiconductor layer was formed on the light absorbing layer made of a p-type I-III-VI group ₂ compound semiconductor (CuInS ₂ ) by MOCVD. Deposited. Subsequently, a 500 nm-thick ITO film was deposited as a transparent electrode layer by a sputtering method to obtain a photovoltaic device. The photoelectric conversion efficiency of this photovoltaic device is 9.1% (AM 1.5, 100 mW / c
m ² ). The photoelectric conversion efficiency was inferior to the case of Example 1 where the crystallization temperature of the amorphous alloy was 400 ° C. or higher.

In the same manner as in Example 2, a p-type I-III-VI group ₂ compound semiconductor (CuI
When a light absorbing layer made of nS ₂ ) was continuously formed,
During the formation, cracks occurred in the amorphous alloy ribbon. As a result of again measuring the cracked amorphous alloy ribbon by X-ray diffraction, crystallization occurred.

[0054]

According to the photovoltaic device of the first aspect, I-
Since the orientation of the III-VI group ₂ compound is increased and the crystal defects in the light absorbing layer are reduced, the diffusion length of the photocarrier is increased, so that high photoelectric conversion efficiency is obtained.
According to the photovoltaic device of the second aspect, the constituent materials of the photovoltaic device can be reduced, and the photovoltaic device can be manufactured continuously, and the photovoltaic device having high photoelectric conversion efficiency can be obtained. The cost of the power device can be reduced, and the productivity can be improved.

According to the photovoltaic devices of the third and fourth aspects, crystallization of the amorphous alloy can be suppressed, and II
Orientation increases the II-VI ₂ group compound, since the diffusion length of photocarriers is lengthened by crystal defects in the light absorbing layer is reduced, a higher photoelectric conversion efficiency can be obtained. According to the photovoltaic device of the fifth aspect, since the optical carriers can be effectively collected, high photoelectric conversion efficiency can be obtained. According to the photovoltaic device of claim 6, the short wavelength sensitivity is improved,
High photoelectric conversion efficiency can be obtained. According to the photovoltaic device of the seventh aspect, the junction characteristics between the light absorbing layer and the layer in contact with the light absorbing layer are improved, so that high photoelectric conversion efficiency can be obtained.

According to the photovoltaic device of the eighth aspect, since high photoelectric conversion efficiency is obtained and no harmful substances are contained,
A highly safe photovoltaic device can be obtained. According to the method of manufacturing a photovoltaic device according to the ninth aspect, it is possible to manufacture a large amount of a light absorbing layer having a large area, and to reduce the manufacturing cost of the photovoltaic device. Claim 10 or 1
According to the method for manufacturing a photovoltaic device, the photovoltaic device can be manufactured continuously, and the productivity of the photovoltaic device can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a photovoltaic device of the present invention.

FIG. 2 is a cross-sectional view schematically showing another example of the photovoltaic device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2 Conductive layer made of amorphous alloy 2A Amorphous alloy ribbon (also serving as base and conductive layer) 3 Light absorbing layer made of I-III-VI group ₂ compound semiconductor 4 Semiconductor layer 5 Transparent electrode layer

Claims (11)

[Claims] 1. A photovoltaic device having a I-III-VI ₂ group compound of semiconductor optical absorption layer and a conductive layer formed on the opposite side of the light incident side in contact with the light-absorbing layer, conductive A photovoltaic device wherein the layer comprises an amorphous alloy. 2. A photovoltaic device comprising: a light absorbing layer made of a group I-III-VI group ₂ compound semiconductor; and a conductive layer formed in contact with the light absorbing layer and on a side opposite to a light incident side. A photovoltaic device, wherein the layer is an amorphous alloy ribbon also serving as a substrate. 3. The photovoltaic device according to claim 1, wherein the crystallization temperature of the amorphous alloy is 400 ° C. or higher. 4. An amorphous alloy comprising Fe, Co, Ni, C
at least one selected from the group consisting of transition metals containing 1 to 6 kinds of r, Cu, and Pd and solid solutions thereof;
It is constituted by at least one element selected from the group consisting of elements including one to ten kinds of C, Si, P, Ge, Ti, Zr, Hf, Nb and Ta and solid solutions thereof. 4. The photovoltaic device according to 1, 2, or 3. 5. The photovoltaic device according to claim 1, wherein the sheet resistance value of the conductive layer is 50 Ω / □ or less. 6. The light according to claim 1, further comprising a semiconductor material layer having a larger band gap than the light absorbing layer on a light incident side in contact with the light absorbing layer. Electromotive device. 7. The light according to claim 6, wherein the semiconductor material layer comprises a semiconductor layer joined to the light absorbing layer, and a transparent electrode layer formed on the light incident side in contact with the semiconductor layer. Electromotive device. 8. The semiconductor material layer to be joined to the light absorbing layer is characterized by containing at least one selected from the group consisting of ZnS, ZnSe, ZnO and a mixed crystal thereof. 8. The photovoltaic device according to 6 or 7. 9. The manufacturing method of I-III-VI ₂ group compound semiconductor light-absorbing layer and its contact with the light absorbing layer photovoltaic device having a conductive layer formed on the opposite side of the light incident side consisting of Forming a light absorbing layer on a conductive layer made of an amorphous alloy by heating a layer containing Group I and Group III elements in an atmosphere containing at least Group VI element. Production method. 10. A method of manufacturing a I-III-VI ₂ group compound semiconductor light-absorbing layer and its contact with the light absorbing layer photovoltaic device having a conductive layer formed on the opposite side of the light incident side consisting of I-III-VI on amorphous alloy ribbon
_A method for manufacturing a photovoltaic device, comprising continuously forming a light absorption layer made of a Group ₂ compound semiconductor. 11. A method for manufacturing a photovoltaic device having a light absorbing layer made of a group I-III-VI Group ₂ compound semiconductor and a conductive layer formed in contact with the light absorbing layer and on a side opposite to a light incident side. I-III-VI on amorphous alloy ribbon
_A method for manufacturing a photovoltaic device, comprising continuously forming a light absorbing layer made of a Group ₂ compound semiconductor, a semiconductor layer joined to the light absorbing layer, and a transparent electrode layer in contact with the semiconductor layer.