JP5964683B2 - Method for manufacturing photoelectric conversion device - Google Patents

Description

  The present invention relates to a method for manufacturing a photoelectric conversion device in which a buffer layer containing indium sulfide is bonded on a light absorption layer.

  As a photoelectric conversion device used for solar power generation or the like, there is one in which a buffer layer using an indium sulfide-based material is formed on a light absorption layer made of a compound semiconductor such as CIS or CIGS. Such a photoelectric conversion device is described in Patent Document 1, for example.

  In a photoelectric conversion device using such a buffer layer, first, a light absorption layer made of a compound semiconductor is formed on a back electrode. Next, a buffer layer is formed on the light absorption layer by a CBD method using an aqueous solution of indium chloride and thioacedamide. Then, an upper electrode layer made of a transparent conductive film is formed on the buffer layer.

JP 2003-282909 A

  A photoelectric conversion device is always required to improve photoelectric conversion efficiency. 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.

In the method for manufacturing a photoelectric conversion device according to an embodiment of the present invention, an upper main surface of a light absorption layer containing a compound semiconductor is brought into contact with a first aqueous solution in which an indium compound and a sulfur compound are dissolved. Forming a first buffer layer containing indium sulfide on the main surface; and etching an upper portion of the first buffer layer with an acidic aqueous solution or an alkaline aqueous solution ; then, forming an upper main surface of the first buffer layer with an indium compound and sulfur. Forming a second buffer layer containing indium sulfide on the upper main surface of the first buffer layer by contacting with a second aqueous solution in which the compound is dissolved .

  ADVANTAGE OF THE INVENTION According to this invention, the photoelectric conversion efficiency of a photoelectric conversion apparatus can be improved.

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 Raman spectrum result of the 2nd semiconductor layer produced using the manufacturing method of the photoelectric conversion device concerning one embodiment of the present invention. It is a Raman spectrum result of the 2nd semiconductor layer produced using the manufacturing method of the photoelectric conversion apparatus as a comparative example.

  Hereinafter, the manufacturing method of the photoelectric conversion apparatus which concerns on one Embodiment of this invention is demonstrated in detail, referring 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.

<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 (light absorption layer), a second semiconductor layer 4 (buffer layer), an upper electrode layer 5, and a collecting electrode 7. Yes. 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. As a specific example, for example, a blue plate glass (soda lime glass) having a thickness of about 1 to 3 mm may be used as the substrate 1.

  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 with a first conductivity type (here, p-type conductivity type) provided on the main surface (also referred to as one main surface) on the + Z side of the lower electrode layer 2. ). The first semiconductor layer 3 mainly includes a compound semiconductor and has a thickness of about 1 to 3 μm. Examples of the compound semiconductor included in the first semiconductor layer 3 include metal chalcogenides such as II-VI group compounds, I-III-VI group compounds, and I-II-IV-VI group compounds.

The II-VI group compound is a compound of a II-B group element (also referred to as a group 12 element) and a VI-B group element (also referred to as a group 16 element). The I-III-VI group compound is a compound of 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. Further, the I-II-IV-VI group compound is a compound of a group IB element, a group II-B element, a group IV-B element (also referred to as a group 14 element), and a group VI-B element.

Examples of the I-III-VI group compound include CuInSe ₂ (indium diselenide,
CIS), Cu (In, Ga) Se ₂ (also called copper indium gallium selenide, CIGS), Cu (In, Ga) (Se, S) ₂ (diselen copper indium gallium indium gallium, CIGSS)). In addition, the 1st semiconductor layer 3 may be a laminated body of a several layer, for example, may be comprised by the CIGS layer which has a thin CIGSS layer as a surface layer. When the first semiconductor layer 3 includes an I-III-VI group compound, the first semiconductor layer 3 includes the III-B group element and the VI-B group element as in the second semiconductor layer 4 including indium sulfide. Therefore, the electrical connection between the first semiconductor layer 3 and the second semiconductor layer 4 becomes better.

Examples of the I-II-IV-VI group compound include Cu ₂ ZnSnS ₄ (also referred to as CZTS), Cu ₂ ZnSn (S, Se) ₄ (also referred to as CZTSSe), and Cu ₂ ZnSnSe ₄ (also referred to as CZTSe). ) And the like. Moreover, as a II-VI group compound, CdTe etc. are mentioned, for example.

The second semiconductor layer 4 as a buffer layer is a semiconductor layer containing indium sulfide (In ₂ S ₃ ) bonded to the first semiconductor layer 3. The second semiconductor layer 4 may have a conductivity type (here, n-type conductivity type) different from the conductivity type of the first semiconductor layer 3. Note that semiconductors having different conductivity types are semiconductors having different conductive carriers. As described above, when the conductivity type of the first semiconductor layer 3 is p-type, the conductivity type of the second semiconductor layer 4 may be n-type or i-type. There may also 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 is a film containing indium sulfide deposited on the first semiconductor layer 3 when an aqueous solution in which an indium compound and a sulfur compound are dissolved is brought into contact with the first semiconductor layer 3. The second semiconductor layer 4 may be a mixed crystal compound containing at least one of indium hydroxide and indium oxide in addition to indium sulfide.

  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, for example, 10 to 200 nm.

  The upper electrode layer 5 is a transparent conductive film having a second conductivity type (here, n-type conductivity type) provided on the second semiconductor layer 4, and is generated in the first semiconductor layer 3. It is an electrode for extracting electric charge. 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 elements such as Al, B, Ga, In, Sn, Sb, and F. Specific examples of the metal oxide semiconductor containing such an element include, for example, AZO (Aluminum Zinc Oxide), GZO (Gallium Zinc Oxide), I
ZO (Indium Zinc Oxide), ITO (Indium Tin Oxide), FTO (Fluorine tin Oxide)
e) etc.

  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 1Ω · cm or less and a sheet resistance of 50Ω / □ or less. Can do.

  The second semiconductor layer 4 and the upper electrode layer 5 may be made of a material having a property (also referred to as light transmission property) 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.

  Further, from the viewpoint of improving the light transmittance and at the same time, transmitting the current generated by the photoelectric conversion well, the upper electrode layer 5 should have a thickness of 0.05 to 0.5 μm. it can.

  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.

<Method for Manufacturing 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 9 shows a state in the middle of manufacturing a portion corresponding to the cross-section shown in FIG.

  First, the 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 by, for example, a scribe process in which a groove process is performed by irradiating a formation target position while scanning a laser beam by a YAG laser or the like. FIG. 3 is a diagram illustrating a state after the first groove portion P1 is formed.

After forming the first groove portion P <b> 1, the first semiconductor layer 3 is formed on the lower electrode layer 2. The first semiconductor layer 3 can be formed by a so-called vacuum process such as a sputtering method or an evaporation method, or can be formed by a process called a coating method or a printing method. A process referred to as a coating method or a printing method is a process in which a complex solution of constituent elements of the first semiconductor layer 3 is applied onto the lower electrode layer 2 and then dried and heat-treated. FIG. 5 is a diagram illustrating a state after the first semiconductor layer 3 is formed.

  After forming the first semiconductor layer 3, the second semiconductor layer 4 is formed on the first semiconductor layer 3. As shown below, the second semiconductor layer 4 is formed by forming the second buffer layer 4b after the formation of the first buffer layer 4a. First, an upper main surface of the first semiconductor layer 3 is brought into contact with an aqueous solution in which an indium compound and a sulfur compound are dissolved (hereinafter, an aqueous solution in which an indium compound and a sulfur compound are dissolved is referred to as a buffer layer forming solution). A first buffer layer 4 a containing indium sulfide is formed on the upper main surface of the layer 3.

  The contact between the upper main surface of the first semiconductor layer 3 and the buffer layer forming solution is performed, for example, by immersing the substrate 1 including the first semiconductor layer 3 in the buffer layer forming solution, or the first semiconductor layer 3. This can be done by applying a buffer layer forming solution to the upper main surface of the layer 3.

  The indium compound used for the buffer layer forming solution may be any compound that generates indium ions in the solution. For example, indium chloride, indium nitrate, indium acetate, or the like can be used. The molar concentration of the indium compound in the buffer layer forming solution may be a concentration at which the molar concentration of indium atoms is, for example, 1 to 10 mM.

  The sulfur compound used in the buffer layer forming solution is not particularly limited as long as it is easily ionized or hydrolyzed in the solution to generate sulfide ions or hydrogen sulfide ions. For example, an alkali metal such as sodium sulfide or potassium sulfide can be used. Examples thereof include sulfides, hydrogen sulfide, thioamide derivatives such as thiourea and thioacetamide. The concentration of the sulfur compound in the buffer layer forming solution may be a concentration at which the molar concentration of sulfur atoms is, for example, 1 to 100 mM.

  As a solvent used for the buffer layer forming solution, a polar solvent such as water or methanol can be used. The buffer layer forming solution may be acidic or alkaline using hydrochloric acid, ammonia, or the like. Further, the buffer layer forming solution may be set at 40 to 80 ° C., for example, in order to appropriately promote the indium sulfide formation reaction.

  Due to the contact between the upper main surface of the first semiconductor layer 3 and the buffer layer forming solution, the first buffer layer 4 a containing indium sulfide grows on the upper main surface of the first semiconductor layer 3. As for the crystal growth of the first buffer layer 4a, good epi growth progresses in the initial stage. However, when the thickness becomes several tens of nm, the orientation is disturbed and the crystal growth tends to proceed in a random direction. When the thickness of the first buffer layer 4a reaches about 10 to 50 nm, the formation process of the first buffer layer 4a is finished. FIG. 5 is a diagram showing a state after the first buffer layer 4a is formed.

  Next, the upper portion of the first buffer layer 4a is etched to remove the surface portion where the orientation is disturbed. As an etchant used for etching the first buffer layer 4a, an acidic aqueous solution such as hydrochloric acid or an alkaline aqueous solution such as ammonia water can be used. By etching the upper portion of the first buffer layer 4a, the thickness of the first buffer layer 4a is set to about 4 to 20 nm. Thus, the first buffer layer 4a having a crystal structure with high orientation as a whole can be obtained. FIG. 6 is a view showing a state after the upper portion of the first buffer layer 4a is etched.

  Next, the second buffer layer 4b containing indium sulfide is formed on the upper main surface of the first buffer layer 4a by bringing the upper main surface of the first buffer layer 4a after the etching into contact with the buffer layer forming solution. The formation of the second buffer layer 4b may be performed under the same conditions as the formation of the first buffer layer 4a or may be performed under different conditions. For example, the buffer layer forming solution used for forming the second buffer layer 4b and the buffer layer forming solution used for forming the first buffer layer 4a include the type of indium compound, the concentration of indium compound, the type of sulfur compound, and the sulfur compound. The concentration, pH, liquid temperature, etc. may be the same or different. The thickness of the second buffer layer 4b can be about 5 to 30 nm.

  The second semiconductor layer 4 composed of a stacked body of the first buffer layer 4a and the second buffer layer 4b is formed by the processes as described above. Note that the second semiconductor layer 4 may be formed not only by two layers of the first buffer layer 4a and the second buffer layer 4b but also by a laminate of three or more layers by repeating the above method a plurality of times. By forming the second semiconductor layer 4 in such a process, the second semiconductor layer 4 can be made dense and highly oriented, and the first semiconductor layer 3 and the second semiconductor layer 4 can be made. As a result, the photoelectric conversion efficiency of the photoelectric conversion device 11 can be increased. FIG. 7 is a view showing a state after the second semiconductor layer 4 is formed.

  Here, from the viewpoint of smoothly proceeding from the formation process of the first buffer layer 4a through the etching process to the formation process of the second buffer layer 4b, a buffer layer forming solution used for forming the first buffer layer 4a, An acidic aqueous solution may be used for both the etching solution used for etching the upper portion of the first buffer layer 4a and the buffer layer forming solution used for forming the second buffer layer 4b. Thereby, a cleaning process can be simplified and a process can be advanced smoothly.

  Further, after the step of forming the second buffer layer 4b, a step of annealing the first buffer layer 4a and the second buffer layer 4b may be further included. The annealing temperature can be set to 100 to 250 ° C., for example. The annealing time can be 10 to 180 minutes, for example. By performing such an annealing step, the photoelectric conversion efficiency is further increased.

  After forming the second semiconductor layer 4, the upper electrode layer 5 is formed on the second semiconductor layer 4. The upper electrode layer 5 is a transparent conductive film mainly composed of, for example, indium oxide (ITO) containing Sn or zinc oxide (AZO) containing Al, and is formed by sputtering, vapor deposition, or CVD. Etc. can be formed. FIG. 8 is a view showing a state after the upper electrode layer 5 is 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, for example, by performing scribing using a scribe needle having a scribe width of about 40 to 50 μm. FIG. 9 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 connecting conductor 6, for example, a conductive paste in which a metal powder such as Ag is dispersed in a resin binder or the like (also referred to as a conductive paste) is printed so as to draw a desired pattern, This can be formed by solidifying. FIG. 10 is a diagram illustrating 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 about 40-1000 micrometers, for example. Moreover, the 3rd groove part P3 can be formed by mechanical scribing 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.

  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.

  Next, a method for manufacturing the photoelectric conversion device 11 will be described with a specific example.

(Preparation of evaluation sample)
First, a raw material solution for forming the first semiconductor layer 3 was produced. As the raw material solution, a solution obtained by dissolving a single source precursor prepared in accordance with US Pat. No. 6,992,202 in pyridine was used. In addition, as this single source precursor, Cu, In, and phenyl selenol formed one complex molecule, and Cu, Ga, and phenyl selenol formed one complex molecule. Using the body.

  Next, a substrate having a lower electrode layer 2 made of Mo is prepared on the surface of a substrate 1 made of glass, and a raw material solution is applied onto the lower electrode layer 2 by a blade method to form a film. did.

  Next, this film was heated at 550 ° C. for 1 hour in an atmosphere in which selenium vapor was contained in hydrogen gas at a partial pressure ratio of 20 ppmv to form a first semiconductor layer 3 mainly containing CIGS and having a thickness of 2 μm. .

  Next, the second semiconductor layer 4 was formed on the first semiconductor layer 3 as follows. First, each substrate on which the layers up to the first semiconductor layer 3 are formed is immersed in an aqueous solution in which 8.5 mM indium chloride, 27 mM thioacetamide, and 4 mM hydrochloric acid are dissolved. On top of this, the first buffer layer 4a was formed to a thickness of 40 nm. Next, by immersing the first buffer layer 4a in an aqueous solution in which 32 mM hydrochloric acid was dissolved, the surface of the first buffer layer 4a was etched to make the first buffer layer 4a 11 nm thick. Next, the first buffer layer 4a after this etching is immersed in an aqueous solution in which 8.5 mM indium chloride, 27 mM thioacetamide and 4 mM hydrochloric acid are dissolved, so that the top surface of the first buffer layer 4a is The second buffer layer 4b was formed to a thickness of 20 nm. As a result, the second semiconductor layer 4 including the first buffer layer 4a and the second buffer layer 4b is formed.

FIG. 11 shows the measurement result of the Raman spectrum (excitation wavelength: 266 nm) of the second semiconductor layer 4 thus fabricated. Than ^11, it is found to have a peak at 297cm ^-1, 357cm -1 and 622cm ^-1.

  Then, the upper electrode layer 5 made of ZnO doped with Al was formed on the second semiconductor layer 4 by a sputtering method to obtain a photoelectric conversion device 11 as an evaluation sample.

(Production of comparative sample)
Next, a comparative sample was produced. The comparative sample was manufactured in the same manner as the evaluation sample except that the second semiconductor layer was manufactured. The second semiconductor layer of the comparative sample was manufactured as follows. The substrate on which the first semiconductor layer is formed is immersed in an aqueous solution in which 8.5 mM indium chloride, 27 mM thioacetamide, and 4 mM hydrochloric acid are dissolved, so that the first semiconductor layer is formed on the first semiconductor layer. Two semiconductor layers were formed to a thickness of 30 nm.

FIG. 12 shows the measurement result of the Raman spectrum (excitation wavelength: 266 nm) of the second semiconductor layer thus fabricated. FIG. 12 shows that there are peaks at 312 cm ⁻¹ and 622 cm ⁻¹ .

(Measurement of photoelectric conversion efficiency)
The photoelectric conversion efficiency of the thus prepared evaluation sample and comparative sample was measured as follows. Using a so-called steady light solar simulator, the photoelectric conversion efficiency was measured under the conditions where the light irradiation intensity on the light receiving surface of the photoelectric conversion device was 100 mW / cm ² and AM (air mass) was 1.5. As a result, it was found that the photoelectric conversion efficiency of the comparative sample was 15.0%, whereas the photoelectric conversion efficiency of the evaluation sample was 15.7%, which was high.

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

Claims (5)

Forming the first buffer layer containing indium sulfide on the upper main surface of the light absorption layer by bringing the upper main surface of the light absorption layer containing the compound semiconductor into contact with a first aqueous solution in which an indium compound and a sulfur compound are dissolved. When,
After the upper portion of the first buffer layer is etched with an acidic aqueous solution or an alkaline aqueous solution, the upper main surface of the first buffer layer is brought into contact with a second aqueous solution in which an indium compound and a sulfur compound are dissolved to thereby form the first buffer layer. And a step of forming a second buffer layer containing indium sulfide on the upper main surface. 2. The method of manufacturing a photoelectric conversion device according to claim 1 , wherein an acidic aqueous solution is used in the step of etching the upper portion of the first buffer layer, and the acidic aqueous solution is used as the first aqueous solution and the second aqueous solution .   The method for manufacturing a photoelectric conversion device according to claim 1, further comprising a step of annealing the first buffer layer and the second buffer layer after the step of forming the second buffer layer.   The stacked body of the first buffer layer and the second buffer layer has a peak at 297 cm-1, 357 cm-1, and 622 cm-1 in a Raman spectrum. A method for manufacturing a photoelectric conversion device. The method for manufacturing a photoelectric conversion device according to claim 1, wherein an I-III-VI group compound is used as the compound semiconductor.

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