JP2001148489A - Manufacturing method for compound semiconductor solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of a compound semiconductor solar battery for improving crystallinity in a p-type semiconductor layer in manufacturing the compound semiconductor solar battery of pn-junction, which is provided with the p-type semiconductor layer that is mainly formed of copper (Cu) and indium (In). SOLUTION: A metallic film where an indium layer 13 and a copper layer 15 are laminated is formed on a molybdenum layer 12 as an electrode film formed on one side of a glass substrate 10. A solfuration processing is executed on the metallic film and a p-type semiconductor layer 14 formed of CUInS2 is formed. Then, the p-type semiconductor layer 14 is cleaned by KCN solution and a KCN processing for removing the impurity of copper sulfide is executed. An n-type semiconductor layer 16 is formed on the p-type semiconductor layer 14. In manufacturing a compound semiconductor solar battery, the indium layer 13 is formed by evaporation while it is heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a compound semiconductor solar cell, and more particularly, to a method of manufacturing a pn junction compound semiconductor solar cell.

[0002]

2. Description of the Related Art There is a compound semiconductor solar cell having a pn junction light absorbing layer shown in FIG. In FIG.
(A) is a front view of the compound semiconductor solar cell, and FIG.
(B) is a longitudinal sectional view of the compound semiconductor solar cell. In this compound semiconductor solar cell (hereinafter sometimes simply referred to as a solar cell), a molybdenum layer 102 is formed on a glass substrate 100 as an electrode film. This molybdenum layer 1
02, a p-type semiconductor layer 104 and an n-type semiconductor layer 106
Are sequentially laminated, and the n-type semiconductor layer 10 is formed.
A transparent electrode 108 is formed on 6. Further, a comb electrode 110 is formed on the transparent electrode 108. As shown in FIG. 4A, the comb-shaped electrode 110 has electrodes formed in a branched shape (comb shape).

The solar cell shown in FIG. 4 can be manufactured by a method shown in FIG. First, an electrode film made of a molybdenum layer 102 is formed on one surface side of a glass substrate 100 by evaporation or sputtering, an indium layer 103 is formed by evaporation at room temperature, and a copper layer 105 is formed on the indium layer 103 at room temperature. [FIG. 5]
Step (a)]. The indium layer 103 and the copper layer 105
Is subjected to heat treatment in a hydrogen sulfide atmosphere to form a p-type semiconductor layer 104 of CuInS ₂ , and then the sulfide (Cu
_In order to remove impurities such as xS _Y ) and optimize the characteristics of the p-type semiconductor layer 104 to obtain stable characteristics,
The p-type semiconductor layer 10 is formed by a KCN solution containing
The surface of No. 4 is subjected to a KCN treatment for cleaning [step of FIG. 5 (b)]. Further, an n-type semiconductor layer 106 is formed on the p-type semiconductor layer 104 by a chemical solution deposition method (step of FIG. 5C), and ZnO: Al or In is further formed on the n-type semiconductor layer 106 by sputtering. Transparent electrode 108 made of ₂ O ₃
[Step (FIG. 5D)]. Then, the transparent electrode 1
By forming a comb-shaped electrode 110 made of aluminum on 08, the solar cell shown in FIG. 4 can be obtained.

[0004]

In the solar cell shown in FIG. 4, the Cu / In atomic concentration ratio of Cu and In forming the p-type semiconductor layer 104 before the KCN treatment (hereinafter simply referred to as Cu / In atomic concentration ratio). Indicates the Cu / In atomic concentration ratio of Cu and In forming the p-type semiconductor layer before the KCN treatment) as much as possible;
And / or by making the p-type semiconductor layer 104 as thick as possible, the crystallinity in the p-type semiconductor layer 104 can be improved,
The power generation efficiency of the solar cell can be improved. However, at present, the limit of the Cu / In atomic concentration ratio of the p-type semiconductor layer 104 is about 1.6 from the viewpoint of the yield rate of the finally obtained solar cell. If the Cu / In atomic concentration ratio is higher than 1.6, the p-type semiconductor layer 104 is easily separated from the electrode film 102 in the KCN processing step. For this reason, in the conventional method of manufacturing a solar cell, it is extremely difficult to improve the power generation efficiency of the solar cell by improving the crystallinity in the p-type semiconductor layer. Also, the layer thickness of the p-type semiconductor layer 104 is limited to about 2 μm. P-type semiconductor layer 10 having a layer thickness exceeding 2 μm
4 is formed, the metal film composed of the indium layer 103 and the copper layer 105 is made thicker.
This is because peeling of the mold semiconductor layer 104 occurs. By the way, if the p-type semiconductor layer 104 can be formed to have a large thickness, the formed p-type semiconductor layer 104 can be chemically etched to make the p-type semiconductor layer as uniform as possible. . However, in the conventional method of manufacturing a solar cell, the thickness p is adjusted to a thickness that can be adjusted by chemical etching.
Since the p-type semiconductor layer 104 cannot be formed and the p-type semiconductor layer 104 has a thickness as uniform as possible, the p-type semiconductor layer 104 must be formed only by sputtering or vapor deposition. For this reason, in the conventional solar cell manufacturing method, it was necessary to very strictly manage the conditions of sputtering and vapor deposition. Accordingly, an object of the present invention is to provide a pn junction compound semiconductor solar cell including a p-type semiconductor layer mainly formed of copper (Cu) and indium (In), It is an object of the present invention to provide a method of manufacturing a compound semiconductor solar cell capable of easily improving the performance.

[0005]

Means for Solving the Problems The present inventors have studied to solve the above problems, and as a result, of the indium layer and the copper layer formed on the electrode film formed on one side of the substrate, the indium layer is heated. The indium layer and the copper layer are formed such that the Cu / In atomic concentration ratio of the p-type semiconductor layer is 1.8 or more and the thickness of the finally obtained p-type semiconductor layer is 2 μm or more. Even if the metal film with the layer is thickened, K
The present inventors have found that in the step of CN treatment, the separation of the p-type semiconductor layer can be suppressed as much as possible, and have reached the present invention. That is, according to the present invention, a metal film formed by laminating an indium layer and a copper layer on an electrode film formed on one surface side of a substrate is formed, and then the metal film is subjected to a sulfurizing treatment or a selenization treatment to form a C film.
After forming a p-type semiconductor layer made of uInS ₂ or CuInSe ₂ , and then subjecting the p-type semiconductor layer to KCN treatment for removing impurities such as copper sulfide and copper selenide by washing with a KCN solution, When manufacturing a compound semiconductor solar cell by forming an n-type semiconductor layer on the type semiconductor layer,
A method of manufacturing a compound semiconductor solar cell, characterized in that the indium layer is formed while being heated, or the indium layer is subjected to heat treatment in a state where the surface of the formed indium layer is exposed.

In the present invention, the temperature of the formation of the indium layer or the temperature of the heat treatment applied to the indium layer is set to a temperature at which the substrate is heated to 120 to 210 ° C., whereby the p-type semiconductor layer in the KCN processing step is formed. Peeling can be further prevented. In addition, a metal film formed by laminating an indium layer and a copper layer is formed so that the Cu / In atom concentration ratio of copper (Cu) and indium (In) forming the p-type semiconductor layer before KCN treatment is 1.8. By forming as described above, the characteristics of the finally obtained solar cell can be improved. Furthermore, K
The p-type semiconductor layer before the CN treatment is formed so as to be thicker than the thickness of the p-type semiconductor layer to be finally formed.
By forming the layer to a predetermined thickness by chemical etching after the N treatment, the control of the conditions for vapor deposition or sputtering for forming the p-type semiconductor layer can be relaxed, or the control of the layer thickness of the p-type semiconductor layer can be controlled by vapor deposition or sputtering. The thickness of the finally formed p-type semiconductor layer can be easily controlled even by plating which is relatively difficult. In particular, a metal film formed by laminating an indium layer and a copper layer has a p-type semiconductor layer having a thickness of 2 to 10 μm after KCN treatment or chemical etching.
By forming so as to be m, the characteristics of the solar cell finally obtained can also be improved.

In the conventional method for manufacturing a compound semiconductor solar cell, in order to prevent the p-type semiconductor layer from peeling off in the KCN treatment step, the p-type semiconductor layer has a Cu / In atomic concentration ratio of 1.6 or less and a final concentration of 1.6% or less. The thickness of the p-type semiconductor layer obtained at
The thickness of the metal film composed of the indium layer and the copper layer is adjusted as described below. For this reason, the crystal grain size of the finally obtained p-type semiconductor layer is small, and the power generation efficiency of the solar cell is low. In this respect, in the present invention, the Cu / In of the p-type semiconductor layer is formed by heating the indium layer while heating the indium layer or performing heat treatment on the indium layer while exposing the surface of the formed indium layer. Even if the thickness of the metal film composed of the indium layer and the copper layer is adjusted so that the atomic concentration ratio is at least 1.8 and the layer thickness of the finally obtained p-type semiconductor layer is at least 2 μm, KCN
Peeling of the p-type semiconductor layer in the processing step can be prevented. Therefore, according to the manufacturing method of the present invention, Cu / In of the p-type semiconductor layer is used.
The result that the thickness of the metal film composed of the indium layer and the copper layer can be adjusted so that the atomic concentration ratio can be higher than before and the finally obtained p-type semiconductor layer can be formed thicker than before. In addition, the crystallinity in the p-type semiconductor layer can be improved, and the power generation efficiency of the pn junction compound semiconductor solar cell obtained by the present invention can be improved more than the power generation efficiency of the conventional compound semiconductor solar cell. Furthermore, the layer thickness of the p-type semiconductor layer after the KCN treatment can be made larger than the layer thickness of the p-type semiconductor layer obtained by performing the KCN treatment by the conventional method for manufacturing a compound semiconductor solar cell. The thickness of the p-type semiconductor layer can be adjusted by performing chemical etching. For this reason, it is possible to relax the control of the conditions of sputtering and vapor deposition for forming the p-type semiconductor layer, or even by plating in which the control of the layer thickness of the p-type semiconductor layer is difficult as compared with vapor deposition or sputtering. The thickness of the finally formed p-type semiconductor layer can be easily controlled.

[0008]

FIG. 1 shows an example of a method for manufacturing a compound semiconductor solar cell according to the present invention. In the manufacturing method shown in FIG. 1, first, an electrode film composed of a molybdenum layer 12 is formed on one surface side of the glass substrate 10 by vapor deposition or sputtering (step of FIG. 1A), and then the glass substrate 10 is heated (see FIG. 1A). (Not shown), the indium layer 13 is formed by vapor deposition (step of FIG. 1B). The heating by the heater is performed when the glass substrate 10 measured by a temperature sensor such as a thermocouple mounted on the glass substrate 10 under a vacuum atmosphere
The heating is performed so as to be 0 to 210 ° C (preferably 140 to 190 ° C). The heating may be performed after forming the indium layer 13 by vapor deposition at room temperature and then exposing the surface of the indium layer 13 or in an atmosphere of a non-oxidizing gas such as nitrogen gas. You may.

As described above, after the indium layer 13 is formed while being heated, or after the surface of the formed indium layer 13 is exposed, the indium layer 13 is subjected to a heat treatment, and then the indium layer 13 is formed on the indium layer 13. A copper layer 15 is formed by vapor deposition (step of FIG. 1C). The copper layer 15 may be formed by vapor deposition while heating the glass substrate 10 by a heater, or may be formed by vapor deposition at room temperature. However, even if a heat treatment is performed after forming the copper layer 15 on the indium layer 13 formed by vapor deposition at room temperature, the Cu / In atomic concentration ratio of the p-type semiconductor layer 14 is 1.
It is extremely difficult to set it to 8 or more. Here, FIG.
In the steps (b) and (c), after the indium layer 13 was formed, the copper layer 15 was formed on the indium layer 13, but after the copper layer 15 was formed on the electrode film 12 at room temperature, the glass substrate 10 was formed. May be formed on the copper layer 15 while heating, or the indium layer 1 may be formed on the copper layer 15 at room temperature.
After forming the layer 3, the indium layer 13 may be subjected to a heat treatment in a state where the surface of the indium layer 13 is exposed. In the steps of FIGS. 1B and 1C, the indium layer 13 and the copper layer 15 are formed by vapor deposition, but may be formed by sputtering or plating, or by using vapor deposition, sputtering, and plating in combination. Is also good.

[0010] The metal film comprising the indium layer 13 and the copper layer 15 is subjected to a heat treatment in a hydrogen sulfide atmosphere to form a CuInS ₂ p-type semiconductor layer 14. This sulfurating treatment can be performed by flowing a gas in which 5 vol% of hydrogen sulfide (H ₂ S) is added to an inert gas such as an argon gas at a temperature of 540 ° C. for about 2 hours. The surface of the p-type semiconductor layer 14 thus obtained is washed with a KCN solution containing 5 to 10% by weight of KCN, and the sulfide (C
u _x S _Y) or the like characteristics of the p-type semiconductor layer 14 remove impurities by optimizing subjected to KCN process to stable characteristics of [step shown in FIG. 1 (d)]. In such a KCN treatment, cleaning of the p-type semiconductor layer 14 can be performed by immersing the p-type semiconductor layer 14 for about 1 to 5 minutes. This KCN
In the processing step, the indium layer 13 is formed while being heated (step in FIG. 1B), so that the Cu / In atomic concentration ratio of the p-type semiconductor layer 14 formed by the sulfurization treatment is set to 1.8 or more. Also, the separation phenomenon does not occur due to the KCN treatment of the p-type semiconductor layer 14. On the other hand, when the indium layer 103 is formed without heating as in the conventional manufacturing process shown in FIG. 5, the p-type semiconductor layer 104 formed by the sulfurating treatment is formed.
If the Cu / In atomic concentration ratio of the p-type semiconductor layer immediately before the KCN treatment is higher than 1.6, a phenomenon occurs in which the p-type semiconductor layer 14 is separated from the molybdenum layer 12 by the KCN treatment. The thickness of the p-type semiconductor layer 14 is 2 μm.
Even with the above, since the p-type semiconductor layer 14 does not peel off, the p-type semiconductor layer 14 subjected to the KCN treatment is subjected to chemical etching to adjust the layer thickness and to form the p-type semiconductor layer 14 having a uniform layer thickness. Can be formed. Thus, the p-type semiconductor layer 1
4 can be subjected to chemical etching, so that the control of the conditions of the vapor deposition and sputtering for forming the indium layer 13 and the copper layer 15 can be eased, or the layer thickness can be controlled as compared with vapor deposition and sputtering as described later. The indium layer 13 and the copper layer 15 can be formed by difficult plating.

An n-type semiconductor layer 16 is formed on the p-type semiconductor layer 14 thus formed by a chemical solution deposition method (step of FIG. 1E). Such n-type semiconductor layer 16
Are ZnSO ₄ (0.1 mol / l), thiourea (0.6 mol / l) and NH ₃ aqueous solution ( ₃ mol / l)
1 / liter) was mixed and maintained at 80 ° C., and about 1 glass substrate 10 on which the p-type semiconductor layer 14 was formed was added.
It can be formed by immersion for about 0 minutes. This step is for the case where the n-type semiconductor layer 14 is made of ZnS, and when the n-type semiconductor layer 14 is made of CdS, cadmium iodide (0.0
015 mol / liter), NH ₃ aqueous solution (1.0 mol
l / liter) and ammonium iodide (0.01 mol
1 / liter), and the mixture was heated. When the temperature reached about 40 ° C., thiourea (0.15 mol /
Liter) and immersion at 80 ° C. for 5 minutes. Further, a transparent electrode 18 made of ZnO doped with Al is formed on the n-type semiconductor layer 16 [step of FIG. 1 (f)]. Thereafter, a comb electrode 110 made of aluminum is formed on the transparent electrode 18 to obtain a solar cell.

According to the method shown in FIG. 1, the p-type semiconductor layer 1
Even if the Cu / In atomic concentration ratio of No. 4 is 1.8 or more, K
Since the separation phenomenon of the p-type semiconductor layer 14 in the CN processing step can be prevented, the crystallinity in the p-type semiconductor layer 14 can be improved, and the manufacturing process is substantially the same as the conventional manufacturing process shown in FIG. Thus, an inexpensive and high-performance solar cell can be obtained. Further, the indium layer 13 is formed by the manufacturing method shown in FIG. 1 such that the finally obtained p-type semiconductor layer 14 has a thickness of 2 to 10 μm (preferably 3 to 6 μm).
It is preferable to adjust the thickness of the metal film including the metal layer and the copper layer 15. Here, if the thickness of the p-type semiconductor layer 14 is less than 2 μm, the crystallinity in the p-type semiconductor layer 14 tends to decrease, while the thickness of the p-type semiconductor layer 14 is 10 μm.
When the thickness exceeds m, the internal resistance of the p-type semiconductor layer 14 tends to increase.

FIG. 2 shows a solar cell obtained by the manufacturing method shown in FIG. 2A is a front view of the solar cell, and FIG. 2B is a perspective view of the solar cell. The solar cell shown in FIG. 2 has a glass substrate 1 as a substrate.
A molybdenum layer 12 is formed on electrode 0 as an electrode film. On the molybdenum layer 12, a p-type semiconductor layer 14 of CuInS ₂ and an n-type semiconductor layer 16 of ZnS are sequentially laminated, and a transparent electrode 18 is formed on the n-type semiconductor layer 16. Further, a comb-shaped electrode 20 is formed on the transparent electrode 18. As shown in FIG. 1A, the comb-shaped electrode 20 has electrodes formed in a branched shape (comb shape). In the solar cell shown in FIG. 2, an electrode terminal 22 that is paired with the comb electrode 20 is formed with a part of the surface of the molybdenum layer 12 exposed. The electrode terminals 22 were previously coated on the molybdenum layer 12 where the electrode terminals were to be formed with a protective resist or mask to form the p-type semiconductor layer 14, the n-type semiconductor layer 16, and the transparent electrode 18. After that, it can be formed by removing the protective resist or mask.

The IV characteristic of the solar cell shown in FIG. 2 is shown as a curve A in FIG. It is a result measured under the condition of AM 1.5 (100 mW / cm ² ). The solar cell exhibiting the IV characteristic of the curve A has a light receiving area (effective area) of 0.25c.
An m ² solar cell was formed as follows. First, on a molybdenum layer 12 having a thickness of about 1 μm formed on one surface side of a glass substrate 10, an indium layer 13 having a thickness of 2000 nm
A metal film comprising a copper layer 15 nm in thickness was formed, and the metal film was subjected to sulfuration treatment to form a p-type semiconductor layer 14 made of CuInS ₂ . The thickness of the p-type semiconductor layer 14 is about 8
μm, and the Cu / In atomic concentration ratio was 3.0. Next, after performing the KCN treatment on the p-type semiconductor layer 14, the p-type semiconductor layer 14 was further subjected to chemical etching to reduce the thickness of the p-type semiconductor layer 14 to about 4 μm. Then, on the p-type semiconductor layer 14,
N-type semiconductor layer 1 made of ZnS having a thickness of 80 to 120 nm
6 and a transparent electrode 18 made of ZnO doped with Al and having a thickness of about 1 μm. The same applies to the case where CdS or InS is used as the n-type semiconductor layer 16.

On the other hand, the IV characteristics of the conventional solar cell shown in FIG. 4 manufactured by the conventional manufacturing method shown in FIG.
Also shown in FIG. The curve B is a result measured under the same conditions as the measurement of the curve A. Curve B I-
A solar cell exhibiting V characteristics has a light receiving area (effective area).
Is 0.25 cm ² , a molybdenum layer 102 having a thickness of about 1 μm formed on a glass substrate 100 and a thickness of about 2 μm.
m and the Cu / In atomic concentration ratio before the KCN treatment is 1.
6, a p-type semiconductor layer 104 of CuInS ₂ ,
80-120 nm thick n-type semiconductor layer 10 of ZnS
6 and Al doped ZnO about 1 μm thick
Of the transparent electrode 18. As apparent from FIG. 3, the IV characteristics of the solar cell of FIG. 2 manufactured by the manufacturing method shown in FIG. 1 are the same as those of the conventional solar cell shown in FIG.
It is better than the characteristics, and the power generation efficiency derived from the IV characteristics shown in FIG. 3 is 11.7%. On the other hand, the power generation efficiency of the conventional solar cell shown in FIG. 4 was 9.7%.

In the manufacturing method shown in FIG.
3 and the copper layer 15 are formed by vapor deposition, but either one or both layers may be formed by plating. However, when the indium layer 13 is formed by plating, it is impossible to form the indium layer 13 while heating such as vapor deposition or sputtering. For this reason, after the indium layer 13 is formed, the indium layer 13 is
To 210 ° C (particularly preferably 140 to 190 ° C). In addition, when the indium layer 13 and / or the copper layer 15 is formed by plating, it is more difficult to control the layer thickness than when the indium layer 13 and the copper layer 15 are formed by vapor deposition or sputtering. Therefore, the p-type semiconductor layer 14 before the KCN treatment is formed to be thicker than the p-type semiconductor layer 14 to be finally formed,
After the CN treatment, chemical etching may be performed to form the p-type semiconductor layer 14 having a predetermined thickness. This chemical etching includes hydrogen peroxide, sulfuric acid, ammonium hydroxide, ammonium persulfate, sodium persulfate, copper sulfate, ammonia, nitric acid,
One or a plurality of compounds selected from the group consisting of phosphoric acid and hydrochloric acid can be used. In particular, hydrogen peroxide is preferred. As described above, the indium layer 13 and / or the copper layer 15 are formed by plating so that the p-type semiconductor layer 14 before the KCN treatment is thicker than the finally formed p-type semiconductor layer 14. Is the p-type semiconductor layer 14
Not only can easily control the layer thickness of Cu, but also the crystal grain size can be increased as much as possible by promoting the growth of CuInS ₂ crystal forming the p-type semiconductor layer 14, and the finally obtained solar cell Power generation efficiency can be improved. When a metal film composed of the indium layer 13 and the copper layer 15 is formed only by vapor deposition or sputtering, the growth of the crystal of CuInS ₂ forming the p-type semiconductor layer 14 is promoted to increase the crystal grain size. In order to increase the size, the p-type semiconductor layer 14 to be finally formed is 2 to 10 μm (preferably 3 to 6 μm).
It is preferable to adjust the thickness of the metal film so that

In the above description, the p-type semiconductor layer 14 of CuInS ₂ is formed by subjecting a metal layer composed of the indium layer 13 and the copper layer 15 to a sulfurating treatment of heating in a hydrogen sulfide atmosphere. Indium layer 13 and copper layer 1
The present invention can also be applied to a case where the metal layer made of No. ₅ is subjected to heat treatment in a hydrogen selenide atmosphere to form a p-type semiconductor layer 14 of CuInSe ₂ . Also, CuInS ₂ forming the p-type semiconductor layer 14
Alternatively, a trace amount of gallium (Ga) may be contained in CuInSe ₂ . Thus, a trace amount of gallium (G
In order to form the p-type semiconductor layer 14 containing a), a gallium layer is formed on the molybdenum layer 12 formed on the substrate surface of the glass substrate 10 by gallium (Ga) or gallium sulfide, for example, in the method shown in FIG. After being formed by sputtering or vapor deposition of (GaS), the indium layer 13 is formed.
And a copper layer 15, or after forming an indium layer 13 and a copper layer 15 on the molybdenum layer 12, similarly forming a gallium layer and then performing a heat treatment in a hydrogen sulfide atmosphere. By performing this, the p-type semiconductor layer 14 made of CuInS ₂ containing a trace amount of gallium (Ga) can be formed. A similar p-type semiconductor layer 14 is formed by forming an indium layer 13 on a molybdenum layer 12 formed on a substrate surface of a glass substrate 10 and then forming a copper (Cu) -gallium (G
a) forming an alloy layer by sputtering or vapor deposition;
Next, it can also be formed by performing a sulfurization treatment of performing a heat treatment in a hydrogen sulfide atmosphere.

[0018]

According to the present invention, the Cu / In atomic concentration ratio of the p-type semiconductor layer before the KCN treatment can be made higher than that of the conventional pn junction compound semiconductor solar cell, and the p-type semiconductor layer finally obtained can be obtained. Since the semiconductor layer can be made thicker than before, the crystallinity in the p-type semiconductor layer can be improved. For this reason, the power generation efficiency of the pn junction compound semiconductor solar cell obtained by the manufacturing method according to the present invention can be higher than that of the pn junction compound semiconductor solar cell obtained by the conventional manufacturing method. As a result, the spread of pn junction compound semiconductor solar cells can be achieved. Also, the p-type semiconductor layer subjected to the KCN treatment can be formed thicker than before, and the layer thickness of the p-type semiconductor layer finally obtained by chemical etching can be adjusted, so that the metal layer composed of the indium layer and the copper layer is formed. A pn-junction compound semiconductor solar cell that can be easily formed and whose power generation efficiency has been improved compared to the related art can be easily formed.

[Brief description of the drawings]

FIG. 1 is a process diagram illustrating an example of a method for manufacturing a compound semiconductor solar cell according to the present invention.

2 is a front view and a perspective view of a compound semiconductor solar cell obtained by the manufacturing method shown in FIG.

FIG. 3 is a graph showing I- of the solar cell obtained by the manufacturing method shown in FIG.
5 is a graph showing V characteristics.

FIG. 4 is a front view and a longitudinal sectional view for explaining an example of a conventional compound semiconductor solar cell.

FIG. 5 is a process chart illustrating an example of a method for manufacturing the conventional compound semiconductor solar cell shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 glass substrate 12 molybdenum layer (electrode film) 13 indium layer 14 p-type semiconductor layer 15 copper layer 16 n-type semiconductor layer 18 transparent electrode layer 20 comb-shaped electrode

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor: Sumitomo Ichikawa, Nagano City, Nagano Pref.

Claims (5)

[Claims] 1. A metal film formed by laminating an indium layer and a copper layer on an electrode film formed on one surface side of a substrate, and then the metal film is subjected to sulfidation treatment or selenization treatment to form a C film.
forming a p-type semiconductor layer made of uInS ₂ or CuInSe ₂ , and then removing the impurities such as copper sulfide and copper selenide by washing the p-type semiconductor layer with a KCN solution.
After performing the treatment, when an n-type semiconductor layer is formed on the p-type semiconductor layer to manufacture a compound semiconductor solar cell, the indium layer is formed while being heated, or a surface of the formed indium layer And subjecting the indium layer to a heat treatment while exposing the compound. 2. The method according to claim 1, wherein the temperature at which the indium layer is formed or the temperature of the heat treatment applied to the indium layer is set to a temperature at which the substrate is heated to 120 to 210 ° C. 3. A metal film formed by laminating an indium layer and a copper layer is coated with copper (Cu) of a p-type semiconductor layer before performing a KCN treatment.
And the indium (In) Cu / In atomic concentration ratio is 1.
3. The method for manufacturing a compound semiconductor solar cell according to claim 1, wherein the number is 8 or more. 4. The p-type semiconductor layer before performing the KCN treatment,
The compound semiconductor solar cell according to any one of claims 1 to 3, wherein the compound semiconductor solar cell is formed so as to be thicker than a thickness of a p-type semiconductor layer to be finally formed, and is formed to a predetermined thickness by chemical etching after KCN treatment. Production method. 5. A metal film formed by laminating an indium layer and a copper layer such that the p-type semiconductor layer after KCN treatment or chemical etching has a thickness of 2 to 10 μm. The method for producing a compound semiconductor solar cell according to any one of the above.