JP2013236043A - Method of manufacturing photoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion device having high photoelectric conversion efficiency.SOLUTION: A method of manufacturing a photoelectric conversion device 11 comprises the steps of: forming, on an electrode layer 2, a film M which contains a group I-B element, an indium element, and a gallium element and contains a sulfur element at least in a surface part on the side opposite to the electrode layer 2; and heating the film M in an atmosphere containing a selenium element to make it into a semiconductor layer 3 containing a group I-III-VI compound.

Description

The present invention relates to a method for manufacturing a photoelectric conversion device using a semiconductor layer containing an I-III-VI group compound.

As a photoelectric conversion device used for solar power generation or the like, there is one in which a semiconductor layer containing an I-III-VI group compound such as CIS or CIGS is used as a light absorption layer. Such a photoelectric conversion device is described in Patent Document 1, for example.

A photoelectric conversion device using such a semiconductor layer containing an I-III-VI group compound has a configuration in which a plurality of photoelectric conversion cells are arranged side by side in a plane. Each photoelectric conversion cell has a substrate such as glass, a lower electrode such as a metal electrode, a photoelectric conversion layer including a light absorption layer and a buffer layer, and an upper electrode such as a transparent electrode and a metal electrode in this order. It is constructed by stacking. In addition, the plurality of photoelectric conversion cells are electrically connected in series by electrically connecting the upper electrode of one adjacent photoelectric conversion cell and the lower electrode of the other photoelectric conversion cell by a connecting conductor. Yes.

  Such a semiconductor layer containing an I-III-VI group compound is formed by forming a film containing a raw material of an I-III-VI group compound on the lower electrode and heat-treating the film.

  As a raw material for the I-III-VI group compound, a salt or a complex of an element constituting the I-III-VI group compound is used. For example, in Patent Document 2, a single source precursor in which Cu, Se, In, or Ga is present in one organic compound is used as a raw material for the I-III-VI group compound. It is described.

JP 2000-299486 A US Pat. No. 6,992,202

An improvement in photoelectric conversion efficiency is always required for a photoelectric conversion device using a semiconductor layer containing an I-III-VI group compound. This photoelectric conversion efficiency indicates the rate at which sunlight energy is converted into electric energy in the photoelectric conversion device. For example, the value of the electric energy output from the photoelectric conversion device is the amount of sunlight incident on the photoelectric conversion device. Divided by the value of energy and derived by multiplying by 100.

  This invention is made | formed in view of the said subject, and aims at the improvement of the photoelectric conversion efficiency in a photoelectric conversion apparatus.

  A method for manufacturing a photoelectric conversion device according to an embodiment of the present invention includes a group IB element, an indium element, and a gallium element on an electrode layer, and at least a sulfur element on a surface portion opposite to the electrode layer. A step of producing a film including the same, and a step of heating the film in an atmosphere including a selenium element to form a semiconductor layer including a group I-III-VI compound.

  According to the embodiment of the present invention, a photoelectric conversion device with high photoelectric conversion efficiency can be provided.

It is a perspective view which shows an example of the photoelectric conversion apparatus produced using the manufacturing method of the photoelectric conversion apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the photoelectric conversion apparatus of FIG. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is sectional drawing which shows typically the mode in the middle of manufacture of a photoelectric conversion apparatus. It is a graph which shows the composition distribution of the thickness direction of a 1st semiconductor layer.

  Hereinafter, a method for manufacturing a photoelectric conversion device according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, parts having similar configurations and functions are denoted by the same reference numerals, and redundant description is omitted in the following description. Further, the drawings are schematically shown, and the sizes, positional relationships, and the like of various structures in the drawings are not accurately illustrated.

<(1) Configuration of photoelectric conversion device>
FIG. 1 is a perspective view showing an example of a photoelectric conversion device 11 manufactured by using a method for manufacturing a photoelectric conversion device according to an embodiment of the present invention. FIG. 2 is an XZ sectional view of the photoelectric conversion device 11 of FIG. 1 to 10 are provided with a right-handed XYZ coordinate system in which the arrangement direction of photoelectric conversion cells 10 (the horizontal direction in the drawing in FIG. 1) is the X-axis direction.

  The photoelectric conversion device 11 has a configuration in which a plurality of photoelectric conversion cells 10 are arranged in parallel on a substrate 1. In FIG. 1, only two photoelectric conversion cells 10 are shown for convenience of illustration, but an actual photoelectric conversion device 11 has a large number of photoelectric conversion cells in the X-axis direction of the drawing or further in the Y-axis direction of the drawing. The conversion cells 10 are arranged two-dimensionally (two-dimensionally).

  Each photoelectric conversion cell 10 mainly includes a lower electrode layer 2, a first semiconductor layer 3, a second semiconductor layer 4, an upper electrode layer 5, and a collecting electrode 7. In the photoelectric conversion device 11, the main surface on the side where the upper electrode layer 5 and the collecting electrode 7 are provided is a light receiving surface. In addition, the photoelectric conversion device 11 is provided with three types of groove portions such as first to third groove portions P1, P2, and P3.

  The substrate 1 supports the plurality of photoelectric conversion cells 10 and is made of, for example, a material such as glass, ceramics, resin, or metal. For example, as the substrate 1, blue plate glass (soda lime glass) having a thickness of about 1 to 3 mm may be used.

  The lower electrode layer 2 is a conductive layer provided on one main surface of the substrate 1. For example, molybdenum (Mo), aluminum (Al), titanium (Ti), tantalum (Ta), or gold (Au). Or a laminated structure of these metals. The lower electrode layer 2 has a thickness of about 0.2 to 1 μm and is formed by a known thin film forming method such as a sputtering method or a vapor deposition method.

The first semiconductor layer 3 as the light absorption layer is provided on a main surface (also referred to as one main surface) on the + Z side of the lower electrode layer 2 and has a first conductivity type (here, p-type conductivity type). ) And has a thickness of about 1 to 3 μm. The first semiconductor layer 3 is a semiconductor layer containing an I-III-VI group compound. The I-III-VI group compound is a group IB element (also referred to as group 11 element), a group III-B element (also referred to as group 13 element), and a group VI-B element (also referred to as group 16 element). It is a compound containing. The first semiconductor layer 3 includes at least an indium element (In) and a gallium element (Ga) as III-B group elements, and at least a selenium element (Se) as a VI-B group element. . As such an I-III-VI group compound, for example, Cu (In, Ga) Se ₂ (also called copper indium gallium selenide, CIGS), Cu (In, Ga) (Se, S) ₂ ( Diselenium, copper indium sulphide, indium gallium, also referred to as CIGSS). In addition, the 1st semiconductor layer 3 may be the thing by which the layer of the I-III-VI group compound of a different composition was laminated | stacked, for example, the laminated body of a CIGS layer and a CIGSS layer may be sufficient as it.

  The second semiconductor layer 4 is a semiconductor layer provided on one main surface of the first semiconductor layer 3. The second semiconductor layer 4 has a conductivity type (here, n-type conductivity type) different from that of the first semiconductor layer 3. By joining the first semiconductor layer 3 and the second semiconductor layer 4, positive and negative carriers generated by photoelectric conversion in the first semiconductor layer 3 are favorably separated. Note that semiconductors having different conductivity types are semiconductors having different conductive carriers. Further, when the conductivity type of the first semiconductor layer 3 is p-type as described above, the conductivity type of the second semiconductor layer 4 may be i-type instead of n-type. Furthermore, there may be a mode in which the conductivity type of the first semiconductor layer 3 is n-type or i-type and the conductivity type of the second semiconductor layer 4 is p-type.

The second semiconductor layer 4 includes, for example, cadmium sulfide (CdS), indium sulfide (In ₂ S ₃ ), zinc sulfide (ZnS), zinc oxide (ZnO), indium selenide (In ₂ Se ₃ ), In (OH , S), (Zn, In) (Se, OH), and (Zn, Mg) O. From the viewpoint of reducing current loss, the second semiconductor layer 4 can have a resistivity of 1 Ω · cm or more. The second semiconductor layer 4 is formed by, for example, a chemical bath deposition (CBD) method or the like.

  The second semiconductor layer 4 has a thickness in the normal direction of one main surface of the first semiconductor layer 3. This thickness is set to, for example, 10 to 200 nm.

  The upper electrode layer 5 is a transparent conductive film provided on the second semiconductor layer 4, and is an electrode that extracts charges generated in the first semiconductor layer 3. The upper electrode layer 5 is made of a material having a lower resistivity than the second semiconductor layer 4. The upper electrode layer 5 includes what is called a window layer, and when a transparent conductive film is further provided in addition to the window layer, these may be regarded as an integrated upper electrode layer 5.

The upper electrode layer 5 mainly includes a material having a wide forbidden band, transparent, and low resistance. As such a material, for example, a metal oxide semiconductor such as ZnO, In ₂ O ₃ and SnO ₂ can be adopted. These metal oxide semiconductors may contain any element of Al, B, Ga, In, F, and the like. Specific examples of the metal oxide semiconductor containing such an element include, for example, AZO (Aluminum Zinc Oxide), GZO (Gallium Zinc Oxide),
Examples include IZO (Indium Zinc Oxide), ITO (Indium Tin Oxide), and FTO (Fluorine tin Oxide).

The upper electrode layer 5 is formed to have a thickness of 0.05 to 3.0 μm by sputtering, vapor deposition, chemical vapor deposition (CVD), or the like. Here, from the viewpoint of good charge extraction from the first semiconductor layer 3, the upper electrode layer 5 has a resistivity of less than 1 Ω · cm and a sheet resistance of 50Ω / □ or less. Can do.

  The second semiconductor layer 4 and the upper electrode layer 5 can be made of a material having a property (also referred to as light transmittance) that allows light to easily pass through the wavelength region of light absorbed by the first semiconductor layer 3. Thereby, a decrease in light absorption efficiency in the first semiconductor layer 3 caused by providing the second semiconductor layer 4 and the upper electrode layer 5 is reduced.

  In addition, from the viewpoint of improving the light transmittance, the effect of preventing loss of light reflection and the light scattering effect, and further transmitting the current generated by the photoelectric conversion, the upper electrode layer 5 can have a thickness of 0.05 to 0.5 μm. Further, from the viewpoint of reducing the light reflection loss at the interface between the upper electrode layer 5 and the second semiconductor layer 4, the absolute refractive index is substantially between the upper electrode layer 5 and the second semiconductor layer 4. It can be made the same.

  The collecting electrodes 7 are spaced apart in the Y-axis direction, and each extend in the X-axis direction. The collector electrode 7 is an electrode having conductivity, and is made of a metal such as silver (Ag), for example.

  The collecting electrode 7 plays a role of collecting charges generated in the first semiconductor layer 3 and taken out in the upper electrode layer 5. If the current collecting electrode 7 is provided, the upper electrode layer 5 can be thinned.

  The charges collected by the collector electrode 7 and the upper electrode layer 5 are transmitted to the adjacent photoelectric conversion cell 10 through the connection conductor 6 provided in the second groove portion P2. For example, the connection conductor 6 is constituted by a portion extending in the Y-axis direction of the current collecting electrode 7 as shown in FIG. Thereby, in the photoelectric conversion apparatus 11, one lower electrode layer 2 of the adjacent photoelectric conversion cell 10 and the other collector electrode 7 are electrically connected via the connection conductor 6 provided in the second groove portion P2. Connected in series. In addition, the connection conductor 6 is not limited to this, You may be comprised by the extension part of the upper electrode layer 5. FIG.

  The current collecting electrode 5 has a width of 50 to 400 μm so that good conductivity is ensured and a decrease in the light receiving area that affects the amount of light incident on the first semiconductor layer 3 is minimized. Can be.

<(2) First Example of Manufacturing Method of Photoelectric Conversion Device>
3 to 10 are cross-sectional views schematically showing a state during the manufacture of the photoelectric conversion device 11. Each of the cross-sectional views shown in FIGS. 3 to 10 shows a state in the middle of manufacturing a portion corresponding to the cross-section shown in FIG.

  First, as shown in FIG. 3, a lower electrode layer 2 made of Mo or the like is formed on substantially the entire surface of the cleaned substrate 1 using a sputtering method or the like. Then, the first groove portion P1 is formed from the linear formation target position along the Y direction on the upper surface of the lower electrode layer 2 to the upper surface of the substrate 1 immediately below the formation position. The first groove portion P1 can be formed, for example, by laser scribing, in which groove processing is performed by irradiating the formation target position while scanning with laser light from a YAG laser or the like. FIG. 4 is a diagram illustrating a state after the first groove portion P1 is formed.

  After the formation of the first groove P1, the lower electrode layer 2 contains a group IB element, an indium element, and a gallium element, and at least a surface portion opposite to the lower electrode layer 2 (hereinafter referred to as a lower portion of the coating M). The surface M on the side opposite to the electrode layer 2 is also simply referred to as the surface portion of the film M), and the film M containing sulfur element is produced. Then, the film M is heated in an atmosphere containing a selenium element to form the first semiconductor layer 3 containing an I-III-VI group compound.

  Thus, by forming the film M containing sulfur element at least on the surface part and selenizing the film M, the surface part (hereinafter referred to as the first semiconductor layer 3) opposite to the lower electrode layer 2 is obtained. The surface portion of the semiconductor layer 3 opposite to the lower electrode layer 2 is also simply referred to as the surface portion of the first semiconductor layer 3), so that the gallium element content can be easily controlled. It can be set as the photoelectric conversion apparatus 11 with a high voltage and high photoelectric conversion efficiency. This is considered to be due to the following reason. When the film M containing a group IB element, an indium element, and a gallium element is selenized, the indium element tends to form a selenide crystal more easily than the gallium element. Therefore, in the surface portion of the coating M where the reaction with the selenium element in the atmosphere is likely to occur, the indium element and the selenium element react with each other and crystallize, and the low-reactivity gallium element tends to move toward the lower electrode layer 2 side. There is. Therefore, in the surface portion of the first semiconductor layer 3, the relative atomic number ratio of the gallium element to the total atomic number of the indium element and the gallium element tends to be low. As a result, the open-circuit voltage becomes small and it is difficult to sufficiently increase the photoelectric conversion efficiency. On the other hand, when the film M containing the sulfur element is formed on at least the surface portion as described above and the film M is selenized, the gallium element tends to easily form a sulfide crystal in the presence of the sulfur element. For this reason, the relative atomic number ratio of the gallium element on the surface portion of the first semiconductor layer 3 can be easily controlled to be increased to some extent. Therefore, it becomes possible to increase the open circuit voltage of the first semiconductor layer 3 and increase the photoelectric conversion efficiency.

  The elements IB group element, indium element, gallium element and sulfur element in the film M may all be uniformly mixed in the film M, but a plurality of elements are present in separate layers. (A state where a specific element exists only in a part in the thickness direction of the film M). This is because if the film M has a thickness of several μm to several tens of μm, even if a plurality of elements exist in different layers, each element diffuses when the film M is heat-treated. This is because each element can react with each other.

  The coating M is produced by using a raw material containing any one or more of group I-B elements, indium elements, gallium elements and sulfur elements, and combining them so as to achieve a desired composition ratio. Can do. Specifically, the coating M can be formed by applying a raw material solution containing the above raw materials, or by sputtering, vapor deposition, or the like. The coating M may be a laminate composed of a plurality of layers.

  Each of the elements IB group element, indium element, gallium element and sulfur element may be present in the film M in a compound state, an alloy state, or a single state. From the standpoint that sulfidation proceeds well inside the coating M and the relative atomic number ratio of gallium elements in the surface portion of the first semiconductor layer 3 to be generated can be easily increased, each of the above elements is an organic ligand. May be present in the film M in the state of an organic complex in which is coordinated. In particular, from the viewpoint of increasing the reactivity and increasing the crystallinity, sulfur element exists as an organic sulfur compound, and this organic sulfur compound is at least one of group IB element, indium element and gallium element. A coordinated organic complex may be used.

  An organic sulfur compound is an organic compound containing a sulfur element, and is an organic compound having a covalent bond between a carbon element and a sulfur element. As the organic sulfur compound, for example, thiol, sulfide, disulfide and the like can be used. Specific examples of organic complexes in which organic sulfur compounds are coordinated include organic complexes in which organic sulfur compounds are coordinated to group IB elements such as copper elements and silver elements, and organic complexes in which organic sulfur compounds are coordinated to indium elements An organic complex in which an organic sulfur compound is coordinated to a gallium element, or an organic sulfur compound is coordinated to both a group I-B element and a group III-B element, and a group I-B element and III in one molecule A single-source organic complex having a group B element and a sulfur element (see Patent Document 2) or the like can be used.

The organic complex containing any of the group IB element, indium element, gallium element and sulfur element as described above is dissolved in an organic solvent such as pyridine or aniline to obtain a raw material solution. The number of moles of sulfur element in the raw material solution can be about 1 to 10 times the total number of moles of group III-B elements. Then, this raw material solution is deposited in the form of a film on the first electrode layer 2 by, for example, a spin coater, screen printing, dipping, spraying, a die coater, etc., and the solvent is removed by drying to form a film M be able to. The coating M may be a multi-layer laminate by repeating the above-described coating forming step. FIG. 5 is a diagram illustrating a state after the film M is formed.

Then, the produced coating M is selenized by heating at 450 to 600 ° C. in an atmosphere in which the selenium element is contained as selenium vapor or hydrogen selenide or the like, whereby a group I-B element, an indium element, The first semiconductor layer 3 containing an I-III-VI group compound (CIGS) containing gallium element and selenium element, or I-III containing IB group element, indium element, gallium element, selenium element and sulfur element The 1st semiconductor layer 3 containing a -VI group compound (CIGSS) can be produced. That is, the sulfur element contained in the film M tends to be replaced by the selenium element in the atmosphere. For example, by adjusting the heating temperature and heating time in the selenization step, the sulfur element is changed to the selenium element. The degree of substitution can be changed. If most of the sulfur element is replaced with selenium element, the first semiconductor layer 3 mainly containing CIGS is formed. If the degree of substitution of the sulfur element with selenium element is low, the first semiconductor layer 3 mainly containing CIGSS is formed. Is formed. FIG. 6 is a diagram showing a state after the first semiconductor layer 3 is formed.

  Note that a selenium element may be further added to the raw material solution for forming the film M. By further adding a selenium element, not only the selenium element in the atmosphere but also the selenium element in the film M can be used as a selenium source in the selenization process of the film M. The selenization reaction can be performed better without unevenness.

  From the viewpoint that the film M can be easily prepared by applying the raw material solution, the selenium element may exist in the state of an organic complex in which an organic ligand is coordinated. From the viewpoint of high reactivity and enhancing crystallinity, selenium element exists as an organic selenium compound, and this organic selenium compound is coordinated to at least one of group IB element, indium element and gallium element. A complex may be used.

An organic selenium compound is an organic compound containing a selenium element, and is an organic compound having a covalent bond between a carbon element and a selenium element. As the organic selenium compound, for example, selenol, selenide, diselenide and the like can be used. Specific examples of the organic complex in which an organic selenium compound is coordinated include an organic complex in which an organic selenium compound is coordinated with an IB group element such as copper element or silver element, and an organic complex in which an organic selenium compound is coordinated with an indium element An organic complex in which an organic selenium compound is coordinated to a gallium element, or an organic selenium compound is a group IB element and III-
A single source organic complex (see Patent Document 2) having a group IB element, a group III-B element, and a selenium element in one molecule by coordinating to both group B elements can be used.

  Moreover, after producing the coating M containing the IB group element, the indium element and the gallium element and containing the sulfur element at least on the surface opposite to the lower electrode layer 2, as described above, Prior to conversion, the coating M may be heated in an atmosphere containing no selenium element, for example, at 50 to 350 ° C. to thermally decompose the organic components in the coating M. Thereby, it can reduce that an organic component remains in the 1st semiconductor layer 3, and can improve the photoelectric conversion efficiency of the 1st semiconductor layer 3 more. In particular, when the organic component in the film M is thermally decomposed, an oxidizing gas such as water vapor or oxygen may be contained in the atmosphere at a partial pressure ratio of about 50 to 300 ppmv. In this case, the metal element on the surface portion of the coating M exists in various forms such as metal oxide, metal sulfide, and metal alloy, and the liquefaction rate, selenization reaction rate, etc. in the subsequent selenization step, etc. A difference occurs in the reactivity. As a result, the reaction proceeds while the microcrystals of the I-III-VI group compound are generated and the surrounding material is still surrounded by the liquefied raw material, so that the first semiconductor layer 3 having high density and high crystallinity is obtained. There is a tendency to become easily.

  After the formation of the first semiconductor layer 3, the second semiconductor layer 4 and the upper electrode layer 5 are sequentially formed on the first semiconductor layer 3.

  The second semiconductor layer 4 can be formed by a solution growth method (also referred to as a CBD method). For example, cadmium acetate and thiourea are dissolved in ammonia water, and the substrate 1 that has been formed up to the formation of the first semiconductor layer 3 is immersed in the second semiconductor layer 3 so as to contain the second CdS on the first semiconductor layer 3. The semiconductor layer 4 can be formed.

  The upper electrode layer 5 is a transparent conductive film containing, for example, indium oxide (ITO) containing Sn as a main component, and can be formed by a sputtering method, a vapor deposition method, a CVD method, or the like. FIG. 7 is a view showing a state after the second semiconductor layer 4 and the upper electrode layer 5 are formed.

  After the upper electrode layer 5 is formed, the second groove portion P2 is formed from the linear formation target position along the Y direction on the upper surface of the upper electrode layer 5 to the upper surface of the lower electrode layer 2 immediately below it. The second groove portion P2 can be formed by, for example, mechanical scribing using a scribe needle. FIG. 8 is a diagram illustrating a state after the second groove portion P2 is formed. The second groove portion P2 is formed at a position slightly deviated in the X direction (+ X direction in the drawing) from the first groove portion P1.

  After forming the second groove P2, the current collecting electrode 7 and the connection conductor 6 are formed. For the collector electrode 7 and the connection conductor 6, for example, a conductive paste (also referred to as a conductive paste) in which a metal powder such as Ag is dispersed in a resin binder or the like is printed so as to draw a desired pattern. It can be formed by heating. FIG. 9 is a view showing a state after the current collecting electrode 7 and the connection conductor 6 are formed.

  After forming the current collection electrode 7 and the connection conductor 6, the 3rd groove part P3 is formed from the linear formation object position of the upper surface of the upper electrode layer 5 to the upper surface of the lower electrode layer 2 just under it. The width | variety of the 3rd groove part P3 can be 40-1000 micrometers, for example. Moreover, the 3rd groove part P3 can be formed by a mechanical scribing process similarly to the 2nd groove part P2. In this way, the photoelectric conversion device 11 shown in FIGS. 1 and 2 is manufactured by forming the third groove portion P3.

<(3) Second Example of Manufacturing Method of Photoelectric Conversion Device>
In the first example of the method for manufacturing the photoelectric conversion device, the coating M is a laminated body (having a three-layer structure of Ma to Mc in FIG. 10) composed of a plurality of layers as shown in FIG. You may make it make the content rate of a sulfur element higher than the other layers Mb and Mc, ie, make the content rate of a sulfur element in the surface part of the membrane | film | coat M the maximum. The other layers Mb and Mc may or may not contain a sulfur element.

  When such a film M is used, in the selenization process of the film M, the gallium element is likely to move away from the lower electrode layer 2 due to the presence of the sulfur element in the uppermost layer Ma of the film M. In the other layers Mb and Mc of M, the content rate of the sulfur element is low, so that the gallium element easily moves to the lower electrode layer 2 side. As a result, the relative atomic number ratio of the gallium element in the first semiconductor layer 3 to be generated increases as the distance from the lower electrode layer 2 increases in the surface portion of the first semiconductor layer 3 as shown in FIG. In addition to the inclination so that the ratio increases, in other parts, a so-called double graded structure in which the relative atomic number ratio increases as the distance from the lower electrode layer 2 is increased tends to be obtained. With such a configuration, the photoelectric conversion efficiency can be further increased.

  In particular, when the degree of substitution of the sulfur element with the selenium element is adjusted so that the sulfur element remains in the first semiconductor layer 3 in the selenization process of the film M, as shown in FIG. The surface portion of the semiconductor layer 3 can be inclined so that the relative atomic number ratio increases as the sulfur element moves away from the lower electrode layer 2. With such a configuration, the contents of both the gallium element and the sulfur element in the surface portion of the first semiconductor layer 3 can be increased, the open-circuit voltage can be further increased, and the photoelectric conversion efficiency can be further increased. .

  FIG. 11 shows the element distribution in the cross section of the first semiconductor layer 3 produced using the coating M having a three-layer structure of Ma to Mc, and the vertical axis represents the total number of atoms of indium element and gallium element. The atomic ratio of gallium element or sulfur element with respect to is shown.

  The present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the coating M containing sulfur element at least on the surface portion is produced using a raw material containing sulfur element. After forming a layer containing a metal element, this film is formed in an atmosphere containing sulfur element. The film M containing sulfur element at least on the surface portion may be formed by heating at

1: Substrate 2: Lower electrode layer 3: First semiconductor layer 4: Second semiconductor layer 5: Upper electrode layer 6: Connection conductor 7: Current collecting electrode 10: Photoelectric conversion cell 11: Photoelectric conversion device M: Film

Claims (7)

A step of forming a film containing a group IB element, an indium element and a gallium element on the electrode layer and containing a sulfur element at least on the surface portion opposite to the electrode layer;
And a step of heating the film in an atmosphere containing a selenium element to form a semiconductor layer containing an I-III-VI group compound.   The manufacturing method of the photoelectric conversion device according to claim 1, wherein the content of the sulfur element in the thickness direction of the coating is maximized in the surface portion.   3. The photoelectric conversion device according to claim 1, wherein the sulfur element is contained in the film as an organic sulfur compound coordinated to at least one of the group IB element, the indium element, and the gallium element. Method.   The method for manufacturing a photoelectric conversion device according to claim 1, wherein in the step of forming the film, the film further includes a selenium element.   The method for manufacturing a photoelectric conversion device according to claim 4, wherein the selenium element is included in the film as an organic selenium compound coordinated to at least one of the group IB element, the indium element, and the gallium element.   The method for producing a photoelectric conversion device according to claim 3 or 5, wherein an organic component contained in the coating is removed by thermal decomposition before heating the coating in an atmosphere containing selenium element.   The photoelectric conversion device according to any one of claims 1 to 6, wherein a part of a surface portion of the coating opposite to the electrode layer is oxidized before the coating is heated in an atmosphere containing selenium element. Method.

Images