JP2011077380A - Photoelectric conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion device that suppresses decline of an open voltage and the shape factor or has an improved open voltage and the shape factor while maintaining a high sensitivity to long wavelengths. <P>SOLUTION: The photoelectric conversion device 100 is provided, in which a p-layer-side gradient layer of an i-layer contains crystalline silicon and crystalline silicon germanium. The concentration of germanium in the p-layer-side gradient layer is in a range the same as or lower than that of a crystalline silicon germanium layer, and the concentration of germanium increases in a stepwise fashion or monotonously from a p-layer-side crystalline silicon layer toward the crystalline silicon germanium layer. The thickness of the p-layer-side crystalline silicon layer is not less than 30% nor more than 50% of the sum of the thicknesses of the p-layer-side crystalline silicon layer and the p-layer-side gradient layer. The sum of the thicknesses of the p-layer-side crystalline silicon layer and the p-layer-side gradient layer is not less than 20% nor more than 50% of the sum of the thicknesses of the p-layer-side crystalline silicon layer, the p-layer-side gradient layer, and the crystalline silicon germanium layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion device, and more particularly to a thin film silicon solar cell in which a power generation layer is formed by film formation.

  Photoelectric conversion devices used in solar cells that convert solar energy into electrical energy include p-type silicon-based semiconductors (p-layers), i-type silicon-based semiconductors (i-layers), and n-type silicon-based semiconductors (n-layers). 2. Description of the Related Art A thin film silicon-based photoelectric conversion device including a photoelectric conversion layer formed by forming a thin film by using a plasma CVD method or the like is known.

  Conventionally, in order to increase the conversion efficiency of a thin-film silicon-based photoelectric conversion device, a technique in which a plurality of photoelectric conversion layers having different band gaps are stacked to form a multi-junction type has been employed. By combining photoelectric conversion layers with different band gaps, it is possible to effectively use solar energy having a wide wavelength range. Known multi-junction photoelectric conversion devices include tandem photoelectric conversion devices in which two photoelectric conversion layers are stacked and bonded, and triple photoelectric conversion devices in which three photoelectric conversion layers are stacked and bonded.

As one of the films of the photoelectric conversion layer used for the multi-junction photoelectric conversion device, a crystalline silicon germanium film can be given. Crystalline silicon germanium is a narrow gap material and is known to have excellent absorption characteristics in the infrared region. Crystalline silicon germanium is expected to be a photoelectric conversion material that can absorb high wavelength sunlight and achieve high efficiency by using it as a laminated structure with other photoelectric conversion materials such as amorphous silicon and crystalline silicon. Has been.
In order to increase the efficiency of the multijunction photoelectric conversion device, the short-circuit current, the open-circuit voltage, and the form factor are important. In the photoelectric conversion device including the crystalline silicon germanium film as the photoelectric conversion layer, the long wavelength sensitivity is improved, so that the short-circuit current density is improved. However, crystalline silicon germanium has a narrow gap compared to crystalline silicon, a point where defect density increases due to inclusion of germanium, and microcrystalline silicon germanium becomes p-type at a high germanium concentration. Therefore, there is a problem that the open circuit voltage and the form factor are lower than that of crystalline silicon.

  Patent Document 1 discloses a photovoltaic element using an amorphous alloy such as amorphous silicon germanium having a narrower band gap than amorphous silicon as an i-type semiconductor layer. This photovoltaic element is characterized in that the band gap of the i-type semiconductor layer is inclined in a predetermined shape, but when a three-layer stack (triple-type) cell is used, the short-circuit current is reduced.

Japanese Patent No. 2719230 (Claim 1, Table 6)

  An object of the present invention is to provide a photoelectric conversion device that suppresses or improves the decrease in open-circuit voltage and form factor while maintaining high long-wavelength sensitivity even when crystalline silicon germanium is used for the photoelectric conversion i layer. And

  In order to solve the above problems, the present invention provides a photoelectric conversion device including a photoelectric conversion layer in which a p layer, an i layer, and an n layer are sequentially stacked on a substrate, wherein the i layer includes p A p-layer side crystalline silicon layer, a p-layer side inclined layer, and a crystalline silicon germanium layer are provided in order from the layer side, and the p-layer side inclined layer includes crystalline silicon and crystalline silicon germanium, Stepwise or monotonous from the p-layer-side crystalline silicon layer toward the crystalline silicon-germanium layer in a concentration range of germanium concentration in the crystalline silicon-germanium layer or less in the concentration range of germanium in the p-layer-side inclined layer The thickness of the p-layer-side crystalline silicon layer is the sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer. 30% or more The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer is the thickness of the p-layer-side crystalline silicon layer and the p-layer. Provided is a photoelectric conversion device that is 20% or more and 50% or less with respect to the sum of the thickness of the layer-side inclined layer and the thickness of the crystalline silicon i layer.

Furthermore, as a result of intensive studies, the present inventors have found that there are appropriate ranges for the film thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer.
By providing a layer (p layer side crystalline silicon layer, p layer side inclined layer) having a lower concentration of germanium contained than the crystalline silicon germanium layer between the p layer and the crystalline silicon germanium layer. The lower part can be made. This avoids the p-type of the i layer on the interface side of the p / i layer and suppresses the distortion of the band gap, so that the open circuit voltage and the shape factor can be improved. The thickness of the p-layer side crystalline silicon layer may be 30% or more and 50% or less with respect to the sum of the thickness of the p-layer side crystalline silicon layer and the thickness of the p-layer side inclined layer. preferable. When the ratio of the thickness of the p-layer-side crystalline silicon layer is 30% or more, an effect of suppressing the reduction of the open-circuit voltage and the shape factor or improving the open-circuit voltage and the shape factor can be obtained. If the film thickness is too large, the concentration of germanium contained in the i layer is lowered and the long wavelength sensitivity is lowered. Therefore, the ratio of the film thickness of the p-layer side crystalline silicon layer is preferably 50% or less.
The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer is equal to the thickness of the p-layer-side crystalline silicon layer, the thickness of the p-layer-side inclined layer, and the crystalline silicon-germanium layer. The thickness is preferably 20% or more and 50% or less with respect to the sum of the film thickness. As a result, there is an effect of improving the open circuit voltage and the form factor while maintaining the long wavelength sensitivity.

  In the above invention, the i layer includes an n-layer-side inclined layer and an n-layer-side crystalline silicon layer in order on the crystalline silicon germanium layer, and the n-layer-side inclined layer includes crystalline silicon and crystals. And the concentration of germanium decreases stepwise or monotonically from the crystalline silicon germanium layer toward the n layer, the thickness of the n-layer-side inclined layer and the n-layer-side crystalline silicon The sum of the thickness of the layers is 10% or more to the sum of the thickness of the p-layer-side crystalline silicon layer, the thickness of the p-layer-side inclined layer, and the thickness of the crystalline silicon-germanium layer. % Or less is preferable.

By providing the n-layer-side inclined layer and the n-layer-side crystalline silicon layer between the crystalline silicon germanium layer and the n-layer, the total film thickness as the i-layer is increased and the short-circuit current is increased.
There is an appropriate range for the total film thickness of the n-layer-side inclined layer and the n-layer-side crystalline silicon layer. The total film thickness is 10% or more and 50% or less with respect to the sum of the thickness of the p-layer side crystalline silicon layer, the thickness of the p-layer side inclined layer, and the thickness of the crystalline silicon germanium layer. Preferably there is. When the total film thickness is 10% or more, the open circuit voltage and the shape factor are improved. On the other hand, if the film thickness is too thick, the defect density in the i layer increases, and the open circuit voltage and the shape factor decrease. Therefore, the total film thickness is preferably 50% or less.

  In the above invention, it is preferable that a photoelectric conversion layer mainly composed of crystalline silicon germanium and two photoelectric conversion layers mainly composed of a semiconductor material having a wider band gap than crystalline silicon germanium are provided on the substrate. The crystalline silicon germanium layer has low spectral sensitivity in the short wavelength region. For example, spectral sensitivity in a short wavelength region can be obtained by including a photoelectric conversion layer mainly composed of a material having a wider band gap than crystalline silicon germanium such as amorphous silicon or crystalline silicon.

  According to the said invention, while maintaining the long wavelength sensitivity of the photoelectric conversion apparatus provided with the crystalline silicon germanium layer, the fall of an open circuit voltage and a form factor can be suppressed. Thereby, it can be set as the photoelectric conversion apparatus of high conversion efficiency.

It is the schematic showing the structure of the photoelectric conversion apparatus of this invention. It is the schematic explaining one Embodiment which manufactures a solar cell panel. It is the schematic explaining one Embodiment which manufactures a solar cell panel. It is the schematic explaining one Embodiment which manufactures a solar cell panel. It is the schematic explaining one Embodiment which manufactures a solar cell panel. It is a figure which shows the germanium concentration profile contained in each layer of crystalline silicon germanium i layer. It is a figure which shows the germanium concentration profile contained in each layer of crystalline silicon germanium i layer. It is a figure which shows the germanium concentration profile contained in each layer of crystalline silicon germanium i layer. It is a graph which shows about the ratio of the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of a crystalline silicon germanium i layer, and the short circuit current of a single type photovoltaic cell. It is a graph which shows about the ratio of the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of a crystalline silicon germanium i layer, and the open circuit voltage of a single type photovoltaic cell. It is a graph which shows about the ratio of the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of a crystalline silicon germanium i layer, and the form factor of a single type photovoltaic cell. It is a graph which shows about the ratio of the sum total of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of a crystalline silicon germanium i layer, and the conversion efficiency of a single type photovoltaic cell. It is a graph which shows about the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer, and the short circuit current of a single type photovoltaic cell. It is a graph which shows about the relationship between the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of a p layer side crystalline silicon layer and a p layer side inclination layer, and the open circuit voltage of a single type photovoltaic cell. It is a graph which shows the relationship between the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer, and the form factor of the single type solar cell. It is a graph which shows about the relationship between the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer, and the conversion efficiency of a single type photovoltaic cell. It is a graph which shows about the ratio of the sum total of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of the crystalline silicon germanium i layer in a triple cell, and a short circuit current. It is a graph which shows about the ratio of the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of the crystalline silicon germanium i layer in a triple cell, and the open circuit voltage. It is a graph which shows about the ratio of the sum of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of the crystalline silicon germanium i layer in a triple cell, and the relationship with a shape factor. It is a graph which shows about the ratio of the sum total of the film thickness of the p layer side crystalline silicon layer and the p layer side inclination layer with respect to the film thickness of the crystalline silicon germanium i layer in a triple cell, and the conversion efficiency. It is a graph which shows about the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of the p layer side crystalline silicon layer and p layer side inclination layer in a triple cell, and the short circuit current. It is a graph which shows about the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of the p layer side crystalline silicon layer and p layer side inclination layer in a triple cell, and an open circuit voltage. It is a graph which shows about the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of the p layer side crystalline silicon layer in a triple cell, and the p layer side inclination layer, and a shape factor. It is a graph which shows about the relationship between the ratio of the film thickness of the p layer side crystalline silicon layer with respect to the sum of the film thickness of the p layer side crystalline silicon layer and p layer side inclination layer in a triple cell, and conversion efficiency. It is a figure which shows the germanium concentration profile contained in each layer of crystalline silicon germanium i layer. The ratio of the sum of the film thicknesses of the n-layer side inclined layer and the n-layer side crystalline silicon layer to the sum of the film thicknesses of the p-layer side crystalline silicon layer, the p-layer side inclined layer, and the crystalline silicon germanium layer, It is a graph which shows the relationship with the short circuit current of a battery cell. The ratio of the sum of the film thicknesses of the n-layer side inclined layer and the n-layer side crystalline silicon layer to the sum of the film thicknesses of the p-layer side crystalline silicon layer, the p-layer side inclined layer, and the crystalline silicon germanium layer, It is a graph which shows the relationship with the open circuit voltage of a battery cell. The ratio of the sum of the film thicknesses of the n-layer side inclined layer and the n-layer side crystalline silicon layer to the sum of the film thicknesses of the p-layer side crystalline silicon layer, the p-layer side inclined layer, and the crystalline silicon germanium layer, It is a graph which shows the relationship with the shape factor of a battery cell. The ratio of the sum of the film thicknesses of the n-layer side inclined layer and the n-layer side crystalline silicon layer to the sum of the film thicknesses of the p-layer side crystalline silicon layer, the p-layer side inclined layer, and the crystalline silicon germanium layer, It is a graph which shows the relationship with the conversion efficiency of a battery cell.

  FIG. 1 is a schematic diagram illustrating a configuration of a photoelectric conversion device of the present invention. The photoelectric conversion device 100 is a triple silicon solar cell, and includes a substrate 1, a transparent electrode layer 2, a first cell layer 91 (amorphous silicon) as a solar cell photoelectric conversion layer 3, and a second cell layer 92 ( Crystalline silicon) and third cell layer 93 (crystalline silicon), intermediate contact layers 5a and 5b, and back electrode layer 4 are provided. Here, the silicon-based is a generic name including silicon (Si), silicon carbide (SiC), and silicon germanium (SiGe). Further, the crystalline silicon system means a silicon system other than the amorphous silicon system, and includes microcrystalline silicon and polycrystalline silicon.

  A method for manufacturing a photoelectric conversion device according to this embodiment will be described by taking a process for manufacturing a solar cell panel as an example. 2 to 5 are schematic views showing a method for manufacturing the solar cell panel of the present embodiment.

(1) FIG. 2 (a)
A soda float glass substrate (for example, 1.4 m × 1.1 m × plate thickness: 3.5 mm to 4.5 mm) is used as the substrate 1. The end face of the substrate is preferably subjected to corner chamfering or R chamfering to prevent damage due to thermal stress or impact.

(2) FIG. 2 (b)
As the transparent electrode layer 2, a transparent conductive film having a thickness of about 500 nm to 800 nm and having tin oxide (SnO ₂ ) as a main component is formed at about 500 ° C. with a thermal CVD apparatus. At this time, a texture with appropriate irregularities is formed on the surface of the transparent electrode film. As the transparent electrode layer 2, an alkali barrier film (not shown) may be formed between the substrate 1 and the transparent electrode film in addition to the transparent electrode film. As the alkali barrier film, a silicon oxide film (SiO ₂ ) is formed at a temperature of about 500 ° C. in a thermal CVD apparatus at 50 nm to 150 nm.

(3) FIG. 2 (c)
Thereafter, the substrate 1 is placed on an XY table, and a p-layer side harmonic (1064 nm) of a YAG laser is irradiated from the film surface side of the transparent electrode film as indicated by an arrow in the figure. The laser power is adjusted to be appropriate for the processing speed, and the transparent electrode film is moved relative to the direction perpendicular to the series connection direction of the power generation cells so that the substrate 1 and the laser light are moved relative to each other to form the groove 10. And laser etching into a strip shape having a predetermined width of about 6 mm to 15 mm.

(4) FIG. 2 (d)
As the first cell layer 91, a p layer, an i layer, and an n layer made of an amorphous silicon thin film are formed by a plasma CVD apparatus. Using SiH ₄ gas and H ₂ gas as main raw materials, the amorphous silicon p layer 31 from the side on which sunlight is incident on the transparent electrode layer 2 at a reduced pressure atmosphere: 30 Pa to 1000 Pa and a substrate temperature: about 200 ° C. Then, an amorphous silicon i layer 32 and an amorphous silicon n layer 33 are formed in this order. The amorphous silicon p layer 31 is mainly made of amorphous B-doped silicon and has a thickness of 10 nm to 30 nm. The amorphous silicon i layer 32 has a thickness of 200 nm to 350 nm. The amorphous silicon n layer 33 is mainly P-doped silicon containing microcrystalline silicon in amorphous silicon, and has a thickness of 30 nm to 50 nm. A buffer layer may be provided between the amorphous silicon p layer 31 and the amorphous silicon i layer 32 in order to improve interface characteristics.

  Next, a crystalline material as the second cell layer 92 is formed on the first cell layer 91 by a plasma CVD apparatus at a reduced pressure atmosphere: 3000 Pa or less, a substrate temperature: about 200 ° C., and a plasma generation frequency: 40 MHz or more and 100 MHz or less. A silicon p layer 41, a crystalline silicon i layer 42, and a crystalline silicon n layer 43 are sequentially formed. The crystalline silicon p layer 41 is mainly made of B-doped microcrystalline silicon and has a thickness of 10 nm to 50 nm. The crystalline silicon i layer 42 is mainly made of microcrystalline silicon and has a film thickness of 1.2 μm or more and 3.0 μm or less. The crystalline silicon n layer 43 is mainly made of P-doped microcrystalline silicon and has a thickness of 20 nm to 50 nm.

Next, a crystalline silicon p layer 61, a crystalline silicon germanium i layer 62, and a crystalline silicon n layer 63 as the third cell layer 93 are formed on the second cell layer 92 using a plasma CVD apparatus. Sequentially form a film.
The crystalline silicon p layer 61 is mainly made of B-doped microcrystalline silicon and has a thickness of 10 nm to 50 nm. The crystalline silicon p layer 61 is formed under the conditions of gas species: SiH ₄ , H ₂ and B ₂ H ₆ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz to 100 MHz.

The crystalline silicon germanium i layer 62 has a configuration in which a p-layer-side crystalline silicon layer, a p-layer-side inclined layer, and a crystalline silicon-germanium layer are sequentially stacked on the crystalline silicon p-layer 61 from the p-layer side. Yes.
The p-layer side crystalline silicon layer has a thickness of 30% or more and 50% or less with respect to the sum of the thickness of the p-layer side crystalline silicon layer and the thickness of the p-layer side inclined layer. It is designed to be In the present embodiment, the p-layer side crystalline silicon layer is a film mainly composed of microcrystalline silicon having a thickness of 60 nm to 250 nm. The present invention is not limited to the scope of this embodiment, and the ratio of the film thickness is important. The p-layer side crystalline silicon layer is manufactured using a plasma CVD apparatus under the conditions of gas types: SiH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz to 100 MHz. Film.

  The p-layer-side gradient layer includes crystalline silicon and crystalline silicon germanium, and has a structure in which the germanium concentration gradually increases from the p-layer side crystalline silicon layer side toward the crystalline silicon germanium layer side. The germanium concentration contained in the p-layer-side gradient layer is set to be equal to or lower than the germanium concentration contained in the crystalline silicon germanium layer. The thickness of the p-layer-side gradient layer is the sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side gradient layer, and the thickness of the p-layer-side crystalline silicon layer and the p-layer-side gradient layer It is designed to be 20% or more and 50% or less with respect to the sum of the thickness of the film and the thickness of the crystalline silicon germanium layer. In the present embodiment, the thickness of the p-layer-side inclined layer is set to 100 nm or more and 400 nm or less. The present invention is not limited to the scope of this embodiment, and the ratio of the film thickness is important.

The p-layer-side gradient layer is formed using a plasma CVD apparatus under conditions of gas types: SiH ₄ , GeH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz or more and 100 MHz or less. Form a film. As a method of changing the germanium concentration in the p-layer-side inclined layer in a stepwise manner, the source gas is supplied every predetermined time so that the germanium concentration increases from the p-layer-side crystalline silicon layer side toward the crystalline silicon-germanium layer side. An example is a method of forming a film by increasing the GeH ₄ flow rate therein. At this time, the crystallinity of the crystalline silicon germanium can be controlled by adjusting the H ₂ flow rate as the GeH ₄ flow rate increases.

The crystalline silicon germanium layer has a film thickness of 500 nm to 800 nm and contains germanium at a concentration of 15 atomic% to 35 atomic%. The crystalline silicon germanium layer is formed using a plasma CVD apparatus under the conditions of gas type: SiH ₄ , GeH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz to 100 MHz. Form a film.

The crystalline silicon germanium i layer 62 may include an n-layer-side inclined layer and an n-layer-side crystalline silicon layer in this order on the crystalline silicon n-layer 63 side.
The n-layer-side inclined layer includes crystalline silicon and crystalline silicon germanium, and has a structure in which the germanium concentration gradually decreases from the crystalline silicon germanium layer side toward the crystalline silicon n layer 63 side. The thickness of the n-layer-side inclined layer is the sum of the thickness of the n-layer-side inclined layer and the thickness of the n-layer-side crystalline silicon layer, and the thickness of the p-layer-side crystalline silicon layer and the p-layer-side inclined layer It is designed to be 10% or more and 50% or less with respect to the sum of the thickness of the film and the thickness of the crystalline silicon germanium layer. In the present embodiment, the thickness of the n-layer-side inclined layer is set to 100 nm or more and 500 nm or less.

The n-layer-side gradient layer is formed using a plasma CVD apparatus under the conditions of gas types: SiH ₄ , GeH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz or more and 100 MHz or less. Form a film. As a method of changing the germanium concentration in the n-layer-side gradient layer stepwise, the GeH ₄ flow rate in the source gas every predetermined time so that the germanium concentration decreases from the p-layer side crystalline silicon layer side to the side. The method of forming into a film by lowering | hanging is mentioned. At this time, the crystallinity of the crystalline silicon germanium can be controlled by adjusting the H ₂ flow rate as the GeH ₄ flow rate increases.

  The n-layer side crystalline silicon layer is a film mainly composed of microcrystalline silicon, and the film thickness is designed according to the description of the film thickness of the n-layer side inclined layer. In this embodiment, the film thickness of the n-layer side crystalline silicon layer is 10 nm or more and 50 nm or less. The film forming conditions are the same as those for the p-layer side crystalline silicon layer.

  In forming an i-layer film mainly composed of a crystalline silicon-based material by the plasma CVD method, the distance d between the plasma discharge electrode and the surface of the substrate 1 is preferably 3 mm or more and 10 mm or less. If it is smaller than 3 mm, it is difficult to keep the distance d constant from the accuracy of each component device in the film forming chamber corresponding to the large substrate, and there is a possibility that the discharge becomes unstable because it is too close. When it is larger than 10 mm, it is difficult to obtain a sufficient film forming speed (1 nm / s or more), and the uniformity of the plasma is lowered and the film quality is lowered by ion bombardment.

  Between the first cell layer 91 and the second cell layer 92, and between the second cell layer 92 and the third cell layer 93, an intermediate layer which becomes a semi-reflective film in order to improve the contact property and achieve current matching Contact layers 5a and 5b are provided, respectively. As intermediate contact layers 5a and 5b, a GZO (Ga-doped ZnO) film having a film thickness of 20 nm to 100 nm is formed by sputtering using a target: Ga-doped ZnO sintered body. In some cases, the intermediate contact layers 5a and 5b are not provided.

(5) FIG. 2 (e)
The substrate 1 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is irradiated from the film surface side of the photoelectric conversion layer 3 as indicated by an arrow in the figure. Pulse oscillation: 10 kHz to 20 kHz, laser power is adjusted so as to be suitable for the processing speed, and laser etching is performed so that grooves 11 are formed on the lateral side of the laser etching line of the transparent electrode layer 2 from about 100 μm to 150 μm. To do. Further, this laser may be irradiated from the substrate 1 side. In this case, the photoelectric conversion layer is formed by utilizing a high vapor pressure generated by the energy absorbed in the amorphous silicon-based first cell layer of the photoelectric conversion layer 3. Since 3 can be etched, a more stable laser etching process can be performed. The position of the laser etching line is selected in consideration of positioning tolerances so as not to intersect with the etching line in the previous process.

(6) FIG. 3 (a)
An Ag film / Ti film is formed as the back electrode layer 4 by a sputtering apparatus at a reduced pressure atmosphere and at a film forming temperature of 150 ° C. to 200 ° C. In this embodiment, an Ag film: 150 nm to 500 nm and a Ti film having a high anticorrosion effect: 10 nm to 20 nm are stacked in this order as a protective film. Alternatively, the back electrode layer 4 may have a laminated structure of an Ag film having a thickness of 25 nm to 100 nm and an Al film having a thickness of 15 nm to 500 nm. For the purpose of reducing the contact resistance between the crystalline silicon n layer 43 and the back electrode layer 4 and improving the light reflection, a film thickness of 50 nm or more and 100 nm or less is formed between the photoelectric conversion layer 3 and the back electrode layer 4 by a sputtering apparatus. A GZO (Ga-doped ZnO) film may be formed and provided.

(7) FIG. 3 (b)
The substrate 1 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is irradiated from the substrate 1 side as indicated by the arrow in the figure. The laser light is absorbed by the photoelectric conversion layer 3, and the back electrode layer 4 is exploded and removed using the high gas vapor pressure generated at this time. Pulse oscillation: laser power is adjusted so as to be suitable for the processing speed from 1 kHz to 10 kHz, and laser etching is performed so that grooves 12 are formed on the lateral side of the laser etching line of the transparent electrode layer 2 from 250 μm to 400 μm. .

(8) FIG. 3 (c) and FIG. 4 (a)
The power generation region is divided, and the film edge around the substrate edge is laser-etched to eliminate the effect of short circuit at the serial connection portion. The substrate 1 is placed on an XY table, and the second harmonic (532 nm) of the laser diode pumped YAG laser is irradiated from the substrate 1 side. The laser light is absorbed by the transparent electrode layer 2 and the photoelectric conversion layer 3, and the back electrode layer 4 explodes using the high gas vapor pressure generated at this time, and the back electrode layer 4 / photoelectric conversion layer 3 / transparent electrode layer 2 is removed. Pulse oscillation: 1 kHz or more and 10 kHz or less, the laser power is adjusted so as to be suitable for the processing speed, and the position of 5 mm to 20 mm from the end of the substrate 1 is placed in the X-direction insulating groove as shown in FIG. Laser etching is performed to form 15. In addition, in FIG.3 (c), since it becomes X direction sectional drawing cut | disconnected in the direction in which the photoelectric converting layer 3 was connected in series, the back surface electrode layer 4 / photoelectric conversion is originally in the position of the insulating groove 15 A state (see FIG. 4A) where there is a peripheral film removal region 14 where the layer 3 / transparent electrode layer 2 is polished and removed should appear, but for convenience of explanation of processing to the end of the substrate 1, The insulating groove formed to represent the Y-direction cross section at the position will be described as the X-direction insulating groove 15. At this time, the Y-direction insulating groove does not need to be provided because the film surface polishing removal processing of the peripheral film removal region of the substrate 1 is performed in a later process.

  The insulating groove 15 exhibits an effective effect in suppressing external moisture intrusion into the solar cell module 6 from the end portion of the solar cell panel by terminating the etching at a position of 5 mm to 15 mm from the end of the substrate 1. Therefore, it is preferable.

  In addition, although the laser beam in the above process is made into a YAG laser, there exists what can use a YVO4 laser, a fiber laser, etc. similarly.

(9) FIG. 4 (a: view from the solar cell film side, b: view from the substrate side of the light receiving surface)
Since the laminated film around the substrate 1 (peripheral film removal region 14) has a step and is easy to peel off in order to ensure a sound adhesion / seal surface with the back sheet 24 via EVA or the like in a later process, The film is removed to form a peripheral film removal region 14. In removing the film over the entire circumference of the substrate 1 at 5 to 20 mm from the end of the substrate 1, the X direction is closer to the substrate end than the insulating groove 15 provided in the step of FIG. The back electrode layer 4 / photoelectric conversion layer 3 / transparent electrode layer 2 are removed by using grinding stone polishing, blast polishing, or the like on the substrate end side with respect to the groove 10 near the side portion.
Polishing debris and abrasive grains were removed by cleaning the substrate 1.

(10) FIGS. 5 (a) and 5 (b)
An attachment portion of the terminal box 23 is provided with an opening through window in the back sheet 24 to take out the current collector plate. Insulating materials are installed in a plurality of layers in the opening through window portion to suppress intrusion of moisture and the like from the outside.
Processing so that power can be taken out from the terminal box 23 on the back side of the solar battery panel by collecting copper foil from one end of the photovoltaic power generation cells arranged in series and the other end of the solar power generation cell. To do. In order to prevent a short circuit with each part, the copper foil arranges an insulating sheet wider than the copper foil width.
After the current collecting copper foil or the like is disposed at a predetermined position, an adhesive filler sheet made of EVA (ethylene vinyl acetate copolymer) or the like is disposed so as to cover the entire solar cell module 6 and not protrude from the substrate 1. .
A back sheet 24 having a high waterproof effect is installed on the EVA. In this embodiment, the back sheet 24 has a three-layer structure of PET sheet / Al foil / PET sheet so that the waterproof and moisture-proof effect is high.
The EVA sheet is placed in a predetermined position until the back sheet 24 is deaerated with a laminator in a reduced pressure atmosphere and pressed at about 150 to 160 ° C., and EVA is crosslinked and brought into close contact.

(11) FIG. 5 (a)
The terminal box 23 is attached to the back side of the solar cell module 6 with an adhesive.
(12) FIG. 5 (b)
The copper foil and the output cable of the terminal box 23 are connected by solder or the like, and the inside of the terminal box 23 is filled with a sealing agent (potting agent) and sealed. Thus, the solar cell panel 50 is completed.
(13) FIG. 5 (c)
A power generation inspection and a predetermined performance test are performed on the solar cell panel 50 formed in the steps up to FIG. The power generation inspection is performed using a solar simulator of AM1.5 and solar radiation standard sunlight (1000 W / m ² ).
(14) FIG. 5 (d)
Before and after the power generation inspection (FIG. 5C), a predetermined performance inspection is performed including an appearance inspection.

  Although the triple solar cell has been described as the solar cell in the above embodiment, the present invention is not limited to this example. The present invention can be similarly applied to other types of thin film solar cells such as a single type solar cell or a tandem type solar cell provided with a photoelectric conversion i layer containing crystalline silicon germanium.

Examples of the photoelectric conversion device according to this embodiment will be described below.
Example 1
Using a glass substrate 1 (1.4 m × 1.1 m × plate thickness: 3.5 to 4.5 mm), a single type solar cell provided with a crystalline silicon germanium i layer on the photoelectric conversion layer 3 was produced.
Transparent electrode layer 2: tin oxide film, film thickness 500 nm to 800 nm
Crystalline silicon p-layer 61: film thickness 10 nm to 50 nm
Crystalline silicon germanium i layer 62: Average film thickness 1000 nm
Crystalline silicon n layer 63: film thickness 20 nm to 50 nm
Back surface transparent electrode layer: GZO film / film thickness 50 nm to 100 nm
Back electrode layer 4: Ag film / film thickness 150 nm to 500 nm, Ti film / film thickness 10 nm to 20 nm

The crystalline silicon germanium i layer includes a p-layer side crystalline silicon layer, a p-layer side inclined layer, and a crystalline silicon germanium layer. The germanium concentration profile contained in each layer of the crystalline silicon germanium i layer is shown in FIG. In the figure, the horizontal axis represents the film thickness of each layer, and the vertical axis represents the germanium concentration.
The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer was 10% of the thickness of the crystalline silicon germanium i layer 62, that is, 100 nm. The thickness of the p-layer side crystalline silicon layer was 50 nm (Example 1-1), 33 nm (Example 1-2), and 25 nm (Example 1-3). The p-layer-side inclined layer has a one-layer, two-layer, or three-layer structure, and the thickness of each layer of the p-layer-side inclined layer is the same. The germanium concentration contained in each layer of the p-layer-side inclined layer was less than 20 atomic%.
The concentration of germanium contained in the crystalline silicon germanium layer was 20 atomic%.

The p-layer side crystalline silicon layer is manufactured using a plasma CVD apparatus under the conditions of gas types: SiH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz to 100 MHz. Filmed.
The p-layer-side gradient layer is formed using a plasma CVD apparatus under conditions of gas types: SiH ₄ , GeH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz or more and 100 MHz or less. A film was formed. At this time, the supply amount of the source gas during film formation was increased stepwise, and the germanium concentration contained in the layer was adjusted to increase from the p-layer side crystalline silicon layer side toward the crystalline silicon germanium layer side. .
The crystalline silicon germanium layer is formed using a plasma CVD apparatus under the conditions of gas type: SiH ₄ , GeH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz to 100 MHz. A film was formed.

(Example 2)
The germanium concentration profile contained in each layer of the crystalline silicon germanium i layer is shown in FIG. In the figure, the horizontal axis represents the film thickness of each layer, and the vertical axis represents the germanium concentration.
The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer in Example 1 is 20% of the thickness of the crystalline silicon germanium i layer 62, that is, 200 nm. It was. The thickness of the p-layer side crystalline silicon layer was 100 nm (Example 2-1), 67 nm (Example 2-2), and 50 nm (Example 2-3). The other layer configuration was the same as in Example 1.

(Example 3)
FIG. 8 shows the germanium concentration profile contained in each layer of the crystalline silicon germanium i layer. In the figure, the horizontal axis represents the film thickness of each layer, and the vertical axis represents the germanium concentration.
The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer in Example 1 is 50% of the thickness of the crystalline silicon germanium i layer 62, that is, 500 nm. It was. The thickness of the p-layer side crystalline silicon layer was 250 nm (Example 3-1), 167 nm (Example 3-2), and 125 nm (Example 3-3). The other layer configuration was the same as in Example 1.

(Comparative Example 1)
The layer configuration was the same as in Example 1 except that the p-layer side crystalline silicon layer and the p-layer side inclined layer were not provided.

The short circuit current, open circuit voltage, form factor, and conversion efficiency of Examples 1 to 3 and Comparative Example 1 were measured. The measurement was performed using a solar simulator of AM1.5 and global solar radiation standard sunlight (1000 W / m ² ).
9 to 12 show the battery characteristics of a single solar cell in which the photoelectric conversion layer 3 is provided with a crystalline silicon germanium i layer, and the p-layer-side crystalline silicon layer and the p with respect to the film thickness of the crystalline silicon germanium i layer. The relationship with the ratio of the sum of the film thickness of a layer side inclination layer is shown. In the figure, the horizontal axis represents the ratio of the sum of the thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer to the thickness of the crystalline silicon germanium i layer. The vertical axis represents the short-circuit current, FIG. 10 is the open circuit voltage, FIG. 11 is the form factor, and FIG. 12 is the conversion efficiency, which are relative values based on the values of Comparative Example 1.

  FIG. 13 to FIG. 16 show the battery characteristics of the single type solar cell provided with the crystalline silicon germanium i layer in the photoelectric conversion layer 3 and the sum of the film thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer. The relationship with the ratio of the film thickness of the p layer side crystalline silicon layer is shown. In the figure, the horizontal axis represents the ratio of the thickness of the p-layer side crystalline silicon layer to the sum of the thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer. The vertical axis represents the short-circuit current, FIG. 14 is the open circuit voltage, FIG. 15 is the shape factor, and FIG. 16 is the conversion efficiency, which are relative values based on the values of Comparative Example 1.

  9 to 12, in all the examples, as the ratio of the sum of the thickness of the p-layer side crystalline silicon layer and the thickness of the p-layer side inclined layer increases, the short-circuit current, the form factor, and the conversion The tendency for the efficiency to increase was confirmed, and a value higher than that of the comparative example was obtained. In particular, when the ratio of the sum of the thickness of the p-layer side crystalline silicon layer and the thickness of the p-layer side inclined layer is 20% or more, a greater improvement effect was obtained. Moreover, the open circuit voltage maintained the same value as the comparative example.

  13 to 16, in all the examples, it was confirmed that the short-circuit current, the shape factor, and the conversion efficiency tend to increase as the ratio of the film thickness of the p-layer side crystalline silicon layer increases. Moreover, the value equivalent to a comparative example or higher than a comparative example was obtained. In particular, the improvement effect was obtained when the ratio of the thickness of the p-layer side crystalline silicon layer was 30% or more. Moreover, the open circuit voltage maintained the same value as the comparative example.

Example 4
A triple solar having a crystalline silicon germanium i layer on a photoelectric conversion layer 3 as shown in FIG. 1 using a glass substrate 1 (1.4 m × 1.1 m × plate thickness: 3.5 to 4.5 mm). A battery cell was produced.
Transparent electrode layer 2: tin oxide film, film thickness 500 nm to 800 nm
Amorphous silicon p layer 31: film thickness 10 nm to 30 nm
Amorphous silicon i layer 32: Average film thickness 150 nm
Amorphous silicon n layer 33: film thickness 30 nm to 50 nm
Intermediate contact layer 5a: film thickness 20 nm to 100 nm
Crystalline silicon p-layer 41: film thickness 10 nm to 50 nm
Crystalline silicon i layer 42: Average film thickness 1000 nm
Crystalline silicon n layer 43: film thickness 20 nm to 50 nm
Intermediate contact layer 5b: film thickness 20 nm to 100 nm
Crystalline silicon p-layer 61: film thickness 10 nm to 50 nm
Crystalline silicon germanium i layer 62: Average film thickness 1000 nm
Crystalline silicon n layer 63: film thickness 20 nm to 50 nm
Back surface transparent electrode layer: GZO film / film thickness 50 nm to 100 nm
Back electrode layer 4: Ag film / film thickness 150 nm to 500 nm, Ti film / film thickness 10 nm to 20 nm

The crystalline silicon germanium i layer 62 includes a p-layer side crystalline silicon layer, a p-layer side inclined layer, and a crystalline silicon germanium layer. The germanium concentration profile contained in each layer of the crystalline silicon germanium i layer 62 and the method for forming the crystalline silicon germanium i layer 62 were the same as in Example 1.
The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer was 10% (100 nm) with respect to the thickness of the crystalline silicon-germanium i layer 62. The thickness of the p-layer side crystalline silicon layer was 50 nm (Example 4-1), 33 nm (Example 4-2), and 25 nm (Example 4-3). The p-layer-side inclined layer has a one-layer, two-layer, or three-layer structure, and the thickness of each layer of the p-layer-side inclined layer is the same. The germanium concentration contained in each layer of the p-layer-side inclined layer was less than 20 atomic%.
The concentration of germanium contained in the crystalline silicon germanium layer was 20 atomic%.

(Example 5)
The sum of the thickness of the p-layer side crystalline silicon layer and the thickness of the p-layer side inclined layer in Example 4 is 20% of the thickness of the crystalline silicon germanium i layer 62, that is, 200 nm. It was. The thickness of the p-layer side crystalline silicon layer was 100 nm (Example 5-1), 67 nm (Example 5-2), and 50 nm (Example 5-3). The other layer configuration was the same as in Example 4.

(Example 6)
The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer in Example 4 is 50% of the thickness of the crystalline silicon germanium i layer 62, that is, 500 nm. It was. The thickness of the p-layer side crystalline silicon layer was 250 nm (Example 6-1), 167 nm (Example 6-2), and 125 nm (Example 6-3). The other layer configuration was the same as in Example 4.

(Comparative Example 2)
The layer configuration was the same as in Example 4 except that the p-layer side crystalline silicon layer and the p-layer side inclined layer were not provided.

The short-circuit current, open-circuit voltage, form factor, and conversion efficiency of Examples 4 to 6 and Comparative Example 2 having a triple cell structure (amorphous silicon / crystalline silicon / crystalline silicon germanium) were measured.
17 to 20, the p-layer side crystalline silicon layer with respect to the battery characteristics of the triple solar cell including the crystalline silicon germanium i layer 62 in the photoelectric conversion layer 3 and the film thickness of the crystalline silicon germanium i layer 62 are shown. And the relationship with the ratio of the sum total of the film thickness of the p layer side inclination layer is shown. In the figure, the horizontal axis represents the ratio of the sum of the thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer to the thickness of the crystalline silicon germanium i layer 62. FIG. 17 shows the short-circuit current, FIG. 18 shows the open-circuit voltage, FIG. 19 shows the shape factor, and FIG. 20 shows the conversion efficiency, which are relative values based on the values of Comparative Example 2.
FIG. 21 to FIG. 24 show the sum of the battery characteristics of the triple solar cell provided with the crystalline silicon germanium i layer 62 in the photoelectric conversion layer 3 and the film thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer. The relationship with the ratio of the film thickness of the p layer side crystalline silicon layer with respect to is shown. In the figure, the horizontal axis represents the ratio of the thickness of the p-layer side crystalline silicon layer to the sum of the thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer. The vertical axis represents a relative value when FIG. 21 is a short-circuit current, FIG. 22 is an open circuit voltage, FIG. 23 is a shape factor, and FIG. 24 is a conversion efficiency.

  17 to 20, in all the examples, the short-circuit current and the open-circuit voltage maintained the same level as compared with Comparative Example 2. Further, the shape factor and the conversion efficiency were higher than those of Comparative Example 2. In particular, when the ratio of the sum of the film thicknesses of the p-layer side crystalline silicon layer and the p-layer side inclined layer was 20% or more, a greater improvement effect was obtained.

  21 to 24, the short-circuit current and the open-circuit voltage were maintained in all Examples as compared with Comparative Example 2. As the ratio of the thickness of the p-layer side crystalline silicon layer increased, the shape factor and the conversion efficiency tended to increase, and a value comparable to or higher than that of the comparative example was obtained. In particular, the improvement effect was obtained when the ratio of the thickness of the p-layer side crystalline silicon layer was 30% or more. According to the above results, it is shown that when the p-layer side crystalline silicon layer and the p-layer side inclined layer are inserted with appropriate thicknesses, a photoelectric conversion device with high conversion efficiency can be obtained while maintaining long wavelength sensitivity. It was done.

(Example 7)
Between the crystalline silicon germanium layer of Example 1 and the crystalline silicon n layer 63, an n layer side inclined layer and an n layer side crystalline silicon layer are sequentially formed as a crystalline silicon germanium i layer from the crystalline silicon germanium layer side. Was established. Other than that, it was set as the layer structure similar to Example 3-1. FIG. 25 shows a germanium concentration profile included in each layer of the crystalline silicon germanium i layer 62. In the figure, the horizontal axis represents the film thickness of each layer of the crystalline silicon germanium i layer 62, and the vertical axis represents the germanium concentration.
The n-layer-side gradient layer was a single-layer film having a germanium concentration of 10 atomic%. The sum of the thickness of the n-layer-side inclined layer and the thickness of the n-layer-side crystalline silicon layer is equal to the thickness of the p-layer-side crystalline silicon layer, the thickness of the p-layer-side inclined layer, and the crystalline silicon-germanium layer. The thickness was set to 10% (Example 7-1), 20% (Example 7-2), and 50% (Example 7-3) with respect to the sum of the film thickness, that is, 100 nm, 200 nm, and 500 nm. The film thickness of the n-layer side inclined layer and the film thickness of the n-layer side crystalline silicon layer were made equal.

The n-layer-side gradient layer is formed using a plasma CVD apparatus under the conditions of gas types: SiH ₄ , GeH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz or more and 100 MHz or less. A film was formed. The supply amount of the source gas during film formation was decreased stepwise to adjust the germanium concentration to 10 atomic%.
The n-layer side crystalline silicon layer is manufactured using a plasma CVD apparatus under the conditions of gas types: SiH ₄ and H ₂ , reduced pressure atmosphere: 3000 Pa or less, substrate temperature: about 200 ° C., plasma generation frequency: 40 MHz to 100 MHz. Filmed.

The short circuit current, open circuit voltage, form factor, and conversion efficiency of Example 7 were measured.
FIGS. 26 to 29 show the battery characteristics of the single type solar battery cell of Example 7, and the n-layer side tilt with respect to the sum of the film thicknesses of the p-layer side crystalline silicon layer, the p-layer side tilted layer, and the crystalline silicon germanium layer. The relationship with the ratio of the sum of the film thickness of the layer and the n-layer side crystalline silicon layer is shown. The horizontal axis is the ratio of the sum of the thicknesses of the n-layer-side tilted layer and the n-layer-side crystalline silicon layer to the sum of the thicknesses of the p-layer-side crystalline silicon layer, the p-layer-side tilted layer, and the crystalline silicon-germanium layer. is there. FIG. 26 shows the short-circuit current, FIG. 27 shows the open circuit voltage, FIG. 28 shows the shape factor, and FIG. 29 shows the conversion efficiency, which are relative values based on the values of Example 3-1.

  Usually, as the film thickness of the crystalline silicon germanium i layer increases, the short-circuit current increases. However, since the defect density in the crystalline silicon germanium i layer increases, the open circuit voltage and the form factor decrease. On the other hand, in Example 7, by providing the thickness of the n-layer-side inclined layer and the n-layer-side crystalline silicon layer between the crystalline silicon germanium layer and the crystalline silicon n-layer 63, the open circuit voltage and The form factor increased and both showed higher values than Example 3-1. The sum of the thickness of the n-layer-side inclined layer and the thickness of the n-layer-side crystalline silicon layer is equal to the thickness of the p-layer-side crystalline silicon layer, the thickness of the p-layer-side inclined layer, and the crystalline silicon-germanium layer. The highest value was obtained when the thickness was 10% of the sum of the thickness. After that, even when the film thickness ratio was 20% or 50%, the same effect as when 10% was obtained.

  According to the above result, in the photoelectric conversion device provided with the crystalline silicon germanium i layer in the photoelectric conversion layer 3, the open-circuit voltage and the form factor can be improved while maintaining high long wavelength sensitivity.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Transparent electrode layer 3 Photoelectric conversion layer 4 Back electrode layer 5a, 5b Intermediate contact layer 6 Solar cell module 31 Amorphous silicon p layer 32 Amorphous silicon i layer 33 Amorphous silicon n layer 41 Crystalline silicon p Layer 42 crystalline silicon i layer 43 crystalline silicon n layer 61 crystalline silicon p layer 62 crystalline silicon germanium i layer 63 crystalline silicon n layer 91 first cell layer 92 second cell layer 93 third cell layer 100 photoelectric conversion apparatus

Claims (3)

A photoelectric conversion device including a photoelectric conversion layer in which a p layer, an i layer, and an n layer are sequentially stacked on a substrate,
The i layer comprises a p layer side crystalline silicon layer, a p layer side inclined layer, and a crystalline silicon germanium layer in order from the p layer side,
The p-layer-side gradient layer includes crystalline silicon and crystalline silicon germanium,
The germanium concentration in the p-layer-side gradient layer is stepwise from the p-layer-side crystalline silicon layer toward the crystalline silicon-germanium layer in a concentration range equal to or lower than the germanium concentration contained in the crystalline silicon-germanium layer. Monotonically increasing germanium concentration,
The thickness of the p-layer side crystalline silicon layer is 30% to 50% of the sum of the thickness of the p-layer side crystalline silicon layer and the thickness of the p-layer side inclined layer. ,
The sum of the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer is the thickness of the p-layer-side crystalline silicon layer and the thickness of the p-layer-side inclined layer, The photoelectric conversion device which is 20% or more and 50% or less with respect to the sum of the thickness of the crystalline silicon germanium layer. The i layer comprises an n-layer-side gradient layer and an n-layer-side crystalline silicon layer in order on the crystalline silicon germanium layer,
The n-layer-side gradient layer includes crystalline silicon and crystalline silicon germanium, and the germanium concentration decreases stepwise or monotonically from the crystalline silicon germanium layer toward the n layer,
The sum of the thickness of the n-layer-side inclined layer and the thickness of the n-layer-side crystalline silicon layer is the thickness of the p-layer-side crystalline silicon layer, the thickness of the p-layer-side inclined layer, The photoelectric conversion device according to claim 1, wherein the photoelectric conversion device has a thickness of 10% or more and 50% or less with respect to the sum of the thickness of the crystalline silicon germanium layer. On the board
A photoelectric conversion layer mainly composed of crystalline silicon germanium;
Two photoelectric conversion layers mainly composed of a semiconductor material having a wider band gap than crystalline silicon germanium;
The photoelectric conversion device according to claim 1 or 2, further comprising:

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