JP7378974B2 - Solar cells, multijunction solar cells, solar cell modules and solar power generation systems - Google Patents
Solar cells, multijunction solar cells, solar cell modules and solar power generation systems Download PDFInfo
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- 238000010248 power generation Methods 0.000 title claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 110
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 claims description 48
- 229940112669 cuprous oxide Drugs 0.000 claims description 48
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 claims description 14
- 229910052710 silicon Inorganic materials 0.000 claims description 11
- 229910044991 metal oxide Inorganic materials 0.000 claims description 10
- 150000004706 metal oxides Chemical group 0.000 claims description 10
- 150000001875 compounds Chemical class 0.000 claims description 9
- 229910052725 zinc Inorganic materials 0.000 claims description 9
- 229910052782 aluminium Inorganic materials 0.000 claims description 8
- 229910052733 gallium Inorganic materials 0.000 claims description 7
- 229910052738 indium Inorganic materials 0.000 claims description 6
- 229910052732 germanium Inorganic materials 0.000 claims description 5
- 229910052796 boron Inorganic materials 0.000 claims description 4
- 239000010408 film Substances 0.000 description 119
- 239000011701 zinc Substances 0.000 description 55
- 239000000758 substrate Substances 0.000 description 42
- 239000007789 gas Substances 0.000 description 35
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 34
- 239000002184 metal Substances 0.000 description 29
- 229910052751 metal Inorganic materials 0.000 description 29
- -1 polyethylene terephthalate Polymers 0.000 description 23
- 238000004544 sputter deposition Methods 0.000 description 23
- 229910006404 SnO 2 Inorganic materials 0.000 description 21
- 238000000231 atomic layer deposition Methods 0.000 description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 18
- 239000011521 glass Substances 0.000 description 18
- 239000001301 oxygen Substances 0.000 description 18
- 229910052760 oxygen Inorganic materials 0.000 description 18
- 229910052786 argon Inorganic materials 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 17
- 238000010438 heat treatment Methods 0.000 description 17
- 239000010949 copper Substances 0.000 description 16
- 238000010586 diagram Methods 0.000 description 15
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 14
- 229910001887 tin oxide Inorganic materials 0.000 description 12
- 238000003860 storage Methods 0.000 description 11
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 10
- 239000004065 semiconductor Substances 0.000 description 10
- 230000005611 electricity Effects 0.000 description 9
- 238000004458 analytical method Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000002834 transmittance Methods 0.000 description 5
- 239000011787 zinc oxide Substances 0.000 description 5
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000010409 thin film Substances 0.000 description 4
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 229910052715 tantalum Inorganic materials 0.000 description 3
- 239000004813 Perfluoroalkoxy alkane Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 229920000840 ethylene tetrafluoroethylene copolymer Polymers 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 229910003437 indium oxide Inorganic materials 0.000 description 2
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920011301 perfluoro alkoxyl alkane Polymers 0.000 description 2
- 238000001420 photoelectron spectroscopy Methods 0.000 description 2
- 229920002493 poly(chlorotrifluoroethylene) Polymers 0.000 description 2
- 229920002492 poly(sulfone) Polymers 0.000 description 2
- 239000005023 polychlorotrifluoroethylene (PCTFE) polymer Substances 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 238000005215 recombination Methods 0.000 description 2
- 230000006798 recombination Effects 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910004613 CdTe Inorganic materials 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 239000004695 Polyether sulfone Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000005345 chemically strengthened glass Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 229910021419 crystalline silicon Inorganic materials 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000002361 inverse photoelectron spectroscopy Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000005424 photoluminescence Methods 0.000 description 1
- 229920001230 polyarylate Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000005361 soda-lime glass Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- YVTHLONGBIQYBO-UHFFFAOYSA-N zinc indium(3+) oxygen(2-) Chemical compound [O--].[Zn++].[In+3] YVTHLONGBIQYBO-UHFFFAOYSA-N 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
- H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
- H01L31/0264—Inorganic materials
- H01L31/0328—Inorganic materials including, apart from doping materials or other impurities, semiconductor materials provided for in two or more of groups H01L31/0272 - H01L31/032
- H01L31/0336—Inorganic materials including, apart from doping materials or other impurities, semiconductor materials provided for in two or more of groups H01L31/0272 - H01L31/032 in different semiconductor regions, e.g. Cu2X/CdX hetero- junctions, X being an element of Group VI of the Periodic Table
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
- H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
- H01L31/0264—Inorganic materials
- H01L31/032—Inorganic materials including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
- H01L31/072—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type
- H01L31/0725—Multiple junction or tandem solar cells
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/52—PV systems with concentrators
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- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Photovoltaic Devices (AREA)
Description
実施形態は太陽電池、多接合型太陽電池、太陽電池モジュール及び太陽光発電システムに関する。 Embodiments relate to solar cells, multijunction solar cells, solar cell modules, and solar power generation systems.
高効率な太陽電池として多接合型（タンデム）太陽電池がある。タンデム太陽電池は、波長帯毎に分光感度が高いセルを用いることができるため、単接合よりも高効率化できる。またタンデム太陽電池のトップセルとして、安価な材料でかつバンドギャップが広い亜酸化銅化合物などが期待されている。 Multijunction (tandem) solar cells are highly efficient solar cells. Tandem solar cells can use cells with high spectral sensitivity for each wavelength band, so they can be more efficient than single junction solar cells. In addition, cuprous oxide compounds, which are inexpensive materials and have a wide bandgap, are expected to be used as the top cell of tandem solar cells.
実施形態は、特性を向上させた太陽電池、多接合型太陽電池、太陽電池モジュール及び太陽光発電システムを提供する。 Embodiments provide solar cells, multijunction solar cells, solar cell modules, and photovoltaic systems with improved characteristics.
実施形態の太陽電池は、透明な第１電極と、第１電極上に亜酸化銅を主体とする光電変換層と、光電変換層上にＺｎ及びＳｉを含む金属酸化物層であるｎ型層と、ｎ型層上に透明な第２電極とを有する。金属酸化物層は、ＺｎｘＳｉｙＭｚＯｗで表される化合物で構成された層であり、ｘ及びｙは、０．９０≦ｘ＋ｙ≦１．００を満たし、ｙは、０．１０≦ｙ≦０．５０を満たし、ｚは、０．００≦ｚ≦０．３０を満たし、ｗは、０．９０≦ｗ≦１．１０を満たし、Ｍは、Ｂ、Ａｌ、Ｇａ、Ｉｎ及びＧｅからなる群から選ばれる１種以上の元素である。光電変換層中に含まれるＺｎ濃度は、光電変換層中に含まれるＳｉ濃度よりも高い。 The solar cell of the embodiment includes a transparent first electrode, a photoelectric conversion layer mainly made of cuprous oxide on the first electrode, and an n-type layer that is a metal oxide layer containing Zn and Si on the photoelectric conversion layer. and a transparent second electrode on the n-type layer. The metal oxide layer is a layer composed of a compound represented by Zn x Si y M z O w , where x and y satisfy 0.90≦x+y≦1.00, and y is 0.10. ≦y≦0.50, z satisfies 0.00≦z≦0.30, w satisfies 0.90≦w≦1.10, M is B, Al, Ga, In and It is one or more elements selected from the group consisting of Ge. The Zn concentration contained in the photoelectric conversion layer is higher than the Si concentration contained in the photoelectric conversion layer.
（第１実施形態）
第１実施形態は、太陽電池に関する。図１に、第１実施形態の太陽電池１００の概念図を示す。図１に示すように、本実施形態に係る太陽電池１００は、第１電極１と、第１電極１上に光電変換層２と、光電変換層２上にｎ型層３と、ｎ型層３上に第２電極４と、を備える。第１電極１と光電変換層２との間やｎ型層３と第２電極４との間には、図示しない中間層が含まれていてもよい。光は第１電極１側から入射しても第２電極４側から入射してもよい。光が太陽電池１００に入射して発電することができる。
(First embodiment)
The first embodiment relates to a solar cell. FIG. 1 shows a conceptual diagram of a solar cell 100 according to the first embodiment. As shown in FIG. 1, the solar cell 100 according to the present embodiment includes a first electrode 1, a photoelectric conversion layer 2 on the first electrode 1, an n-type layer 3 on the photoelectric conversion layer 2, and an n-type layer 3 and a second electrode 4 thereon. An intermediate layer (not shown) may be included between the first electrode 1 and the photoelectric conversion layer 2 or between the n-type layer 3 and the second electrode 4. The light may be incident from the first electrode 1 side or from the second electrode 4 side. Light can be incident on the solar cell 100 to generate electricity.
（第１電極）
実施形態の第１電極１は、光電変換層２側に設けられた透明な導電層である。図１では、第１電極１は、光電変換層２と直接接している。第１電極１としては、透明導電膜、金属膜と透明導電膜と金属膜を積層したものが好ましい。透明導電膜としては、酸化インジウムスズ（Indium Tin Oxide；ＩＴＯ）、アルミニウムドープ酸化亜鉛（Al-doped Zinc Oxide；ＡＺＯ）、ボロンドープ酸化亜鉛（Boron-doped Zinc Oxide；ＢＺＯ）、ガリウムドープ酸化亜鉛（Gallium-doped Zinc Oxide；ＧＺＯ）、フッ素ドープ酸化スズ（Fluorine-doped Tin Oxide；ＦＴＯ）、アンチモンドープ酸化スズ（Antimony-doped Tin Oxide；ＡＴＯ）、チタンドープ酸化インジウム（Titanium-doped Indium Oxide；ＩＴｉＯ）、酸化インジウム酸化亜鉛（Indium Zinc Oxide；ＩＺＯ）や酸化インジウムガリウム亜鉛（Indium Gallium Zinc Oxide；ＩＧＺＯ）、タンタルドープ酸化スズ（Ta-doped Tin Oxide；ＳｎＯ２：Ｔａ）、ニオブドープ酸化スズ（Nb-doped Tin Oxide；ＳｎＯ２：Ｎｂ）、タングステンドープ酸化スズ（W-doped Tin Oxide；ＳｎＯ２：Ｗ）、モリブデンドープ酸化スズ（Mo-doped Tin Oxide；ＳｎＯ２：Ｍｏ）、フッ素ドープ酸化スズ（F-doped Tin Oxide；ＳｎＯ２：Ｆ）、水素ドープ酸化インジウム（Hydrogen-doped Indium Oxide；ＩＯＨ）など特に限定されない。透明導電膜は、複数の膜を持つ積層膜であってもよく、上記酸化物の他に酸化スズなどの膜が積層膜に含まれていてもよい。酸化スズなどの膜へのドーパントとしては、Ｉｎ、Ｓｉ、Ｇｅ、Ｔｉ、Ｃｕ、Ｓｂ、Ｎｂ、Ｆ、Ｔａ、Ｗ、Ｍｏ、Ｆ、Ｃｌなど特に限定されない。金属膜としては、Ｍｏ、Ａｕ、Ｃｕ、Ａｇ、Ａｌ、ＴａやＷの膜など特に限定されない。また、第１電極１は、透明導電膜上にドット状、ライン状もしくはメッシュ状の金属を設けた電極でもよい。このとき、ドット状、ライン状もしくはメッシュ状の金属は、透明導電膜と光電変換層２の間や透明導電膜の光電変換層２とは反対側に配置される。ドット状、ライン状もしくはメッシュ状の金属は、透明導電膜に対して開口率が５０％以上であることが好ましい。ドット状、ライン状もしくはメッシュ状の金属は、Ｍｏ、Ａｕ、Ｃｕ、Ａｇ、Ａｌ、ＴａやＷなど特に限定されない。第１電極１に金属膜を用いる場合、透過性の観点から５ｎｍ以下程度の膜厚とすることが好ましい。ライン状やメッシュ状の金属膜を用いる場合、透過性は開口部で確保されるため、金属膜の膜厚に関してはこの限りではない。
(first electrode)
The first electrode 1 of the embodiment is a transparent conductive layer provided on the photoelectric conversion layer 2 side. In FIG. 1, the first electrode 1 is in direct contact with the photoelectric conversion layer 2. The first electrode 1 is preferably a transparent conductive film, a metal film, and a stack of a transparent conductive film and a metal film. Transparent conductive films include Indium Tin Oxide (ITO), Al-doped Zinc Oxide (AZO), Boron-doped Zinc Oxide (BZO), and Gallium-doped Zinc Oxide (BZO). -doped Zinc Oxide; GZO), Fluorine-doped Tin Oxide (FTO), Antimony-doped Tin Oxide (ATO), Titanium-doped Indium Oxide (ITiO), Indium Zinc Oxide (IZO), Indium Gallium Zinc Oxide (IGZO), Ta-doped Tin Oxide (SnO 2 :Ta), Nb-doped Tin Oxide; SnO 2 :Nb), tungsten-doped tin oxide (W-doped Tin Oxide; SnO 2 :W), molybdenum-doped tin oxide (Mo-doped Tin Oxide; SnO 2 :Mo), fluorine-doped tin oxide (F-doped Tin Oxide (SnO2:F), Hydrogen-doped Indium Oxide (IOH), etc. are not particularly limited. The transparent conductive film may be a laminated film having a plurality of films, and the laminated film may include a film such as tin oxide in addition to the above oxide. Dopants for the film such as tin oxide include In, Si, Ge, Ti, Cu, Sb, Nb, F, Ta, W, Mo, F, and Cl, and are not particularly limited. The metal film is not particularly limited, and may be a film of Mo, Au, Cu, Ag, Al, Ta, or W. Further, the first electrode 1 may be an electrode in which dot-shaped, line-shaped, or mesh-shaped metal is provided on a transparent conductive film. At this time, the dot-shaped, line-shaped, or mesh-shaped metal is arranged between the transparent conductive film and the photoelectric conversion layer 2 or on the side of the transparent conductive film opposite to the photoelectric conversion layer 2. It is preferable that the dot-shaped, line-shaped, or mesh-shaped metal has an aperture ratio of 50% or more with respect to the transparent conductive film. The dot-like, line-like, or mesh-like metal may be Mo, Au, Cu, Ag, Al, Ta, W, or the like, but is not particularly limited. When a metal film is used for the first electrode 1, the film thickness is preferably about 5 nm or less from the viewpoint of transparency. When using a line-shaped or mesh-shaped metal film, the permeability is ensured at the openings, so the thickness of the metal film is not limited to this.
（光電変換層）
実施形態の光電変換層２は、第１電極１とｎ型層３の間に配置された半導体層である。光電変換層２としては、化合物半導体層が好ましい。光電変換層２としては、亜酸化銅を主体（９０ｗｔ％以上）とする半導体層が挙げられる。光電変換層２は、より具体的には、ｐ型の化合物半導体層である。光電変換層２が厚くなると透過率が低下し、また、スパッタでの成膜を考慮すると１０μｍ以下が実用的であり、化合物半導体層としては、亜酸化銅を主体とする半導体層が好ましい。光電変換層２の厚さは、８００ｎｍ以上１０μｍ以下であることが好ましい。化合物半導体層としては、亜酸化銅等を主体とする半導体層には、添加物を含んでもよい。光電変換層２は全体としては、ｐ型（ｐ＋型を含む）である。光電変換層２のｎ型層３側には、一部ｎ型の領域が含まれてもよい。
(Photoelectric conversion layer)
The photoelectric conversion layer 2 of the embodiment is a semiconductor layer arranged between the first electrode 1 and the n-type layer 3. As the photoelectric conversion layer 2, a compound semiconductor layer is preferable. Examples of the photoelectric conversion layer 2 include a semiconductor layer containing cuprous oxide as a main component (90 wt% or more). More specifically, the photoelectric conversion layer 2 is a p-type compound semiconductor layer. As the photoelectric conversion layer 2 becomes thicker, the transmittance decreases, and in consideration of film formation by sputtering, a thickness of 10 μm or less is practical, and the compound semiconductor layer is preferably a semiconductor layer mainly containing cuprous oxide. The thickness of the photoelectric conversion layer 2 is preferably 800 nm or more and 10 μm or less. As a compound semiconductor layer, a semiconductor layer mainly composed of cuprous oxide or the like may contain an additive. The photoelectric conversion layer 2 as a whole is p-type (including p+ type). A part of the n-type region may be included in the photoelectric conversion layer 2 on the n-type layer 3 side.
光電変換層２はスパッタリングによって作製する。スパッタ中の雰囲気は、Ａｒなどの不活性ガスと酸素ガスとの混合ガス雰囲気とすることが好ましい。太陽電池１００を保持する基板の種類にもよるが、基板温度を１００℃以上６００℃以下に加熱して、Ｃｕを含むターゲットを用いてスパッタする。例えば、スパッタリングの温度や酸素分圧を調整することによって大粒径な亜酸化銅薄膜を第１電極１上に成膜することができる。太陽電池１００を作製するために用いる基板（第１電極１を保持する基板）としては、アクリル、ポリイミド、ポリカーボネート、ポリエチレンテレフタレート（ＰＥＴ）、ポリプロピレン（ＰＰ）、フッ素系樹脂（ポリテトラフルオロエチレン（ＰＴＦＥ）、パーフルオロエチレンプロペンコポリマー（ＦＥＰ）、エチレンテトラフルオロエチレンコポリマー（ＥＴＦＥ）、ポリクロロトリフルオロエチレン（ＰＣＴＦＥ）、パーフルオロアルコキシアルカン（ＰＦＡ）など）、ポリアリレート、ポリサルフォン、ポリエーテルサルフォンやポリエーテルイミドなどの有機系の基板やソーダライムガラス、白板ガラス、化学強化ガラスや石英などの無機系の基板を用いることができる。 The photoelectric conversion layer 2 is produced by sputtering. The atmosphere during sputtering is preferably a mixed gas atmosphere of an inert gas such as Ar and oxygen gas. Depending on the type of substrate holding the solar cell 100, the substrate temperature is heated to 100° C. or more and 600° C. or less, and sputtering is performed using a target containing Cu. For example, by adjusting the sputtering temperature and oxygen partial pressure, a large-grain cuprous oxide thin film can be formed on the first electrode 1. The substrate used for manufacturing the solar cell 100 (the substrate holding the first electrode 1) may be made of acrylic, polyimide, polycarbonate, polyethylene terephthalate (PET), polypropylene (PP), fluorine resin (polytetrafluoroethylene (PTFE), etc. ), perfluoroethylene propene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxyalkane (PFA), etc.), polyarylate, polysulfone, polyethersulfone and polysulfone. An organic substrate such as etherimide or an inorganic substrate such as soda lime glass, white glass, chemically strengthened glass, or quartz can be used.
光電変換層２の９５％以上は亜酸化銅で構成されていることが好ましい。光電変換層２の９８％以上が亜酸化銅で構成されていることがより好ましい。つまり、光電変換層２は、ＣｕＯやＣｕ等の異相をほとんど（実質的に）含まないことが好ましい。光電変換層２には、ＣｕＯやＣｕなどの異相が含まれず、実質的にＣｕ２Ｏ単相の薄膜であると、非常に高い透光性となるため好ましい。光電変換層２が実質的にＣｕ２Ｏの単相であることは、フォトルミネッセンス法（Photo Luminescence；ＰＬ法）により測定することで確認できる。 It is preferable that 95% or more of the photoelectric conversion layer 2 is composed of cuprous oxide. More preferably, 98% or more of the photoelectric conversion layer 2 is composed of cuprous oxide. That is, it is preferable that the photoelectric conversion layer 2 hardly (substantially) contains foreign phases such as CuO and Cu. It is preferable that the photoelectric conversion layer 2 does not contain foreign phases such as CuO or Cu and is a thin film of substantially a single phase of Cu 2 O because it has very high light transmittance. That the photoelectric conversion layer 2 is substantially a single phase of Cu 2 O can be confirmed by measurement using a photoluminescence (PL method).
（ｎ型層）
ｎ型層３は、光電変換層２と第２電極４の間に配置されたｎ型の半導体層である。ｎ型層３の光電変換層２を向く面は、光電変換層２のｎ型層３を向く面と直接的に接していることが好ましい。ｎ型層３はアモルファスの薄膜であることが好ましい。ｎ型層３は、Ｚｎ及びＳｉを含む金属酸化物層が好ましい。金属酸化物層（ｎ型層３）は、ＺｎｘＳｉｙＭｚＯｗで表される化合物で構成された層であることが好ましく、ｘ及びｙは、０．９０≦ｘ＋ｙ≦１．００を満たし、ｚは、０．００≦ｚ≦０．３０を満たし、ｗは、０．９０≦ｗ≦１．１０を満たし、Ｍは、Ｂ、Ａｌ、Ｇａ、Ｉｎ及びＧｅからなる群から選ばれる１種以上の元素であることが好ましい。金属酸化物層は、不可避的な不純物を除き実質的にＺｎｘＳｉｙＭｚＯｗであることが好ましい。ｘ、ｙ、ｚ、ｗがこれらの範囲にあることで良好なｎ型層が形成され、更にＣｕ２Ｏ膜とｎ型層の伝導帯の位置を好ましい範囲に収めることができる。
(n-type layer)
The n-type layer 3 is an n-type semiconductor layer disposed between the photoelectric conversion layer 2 and the second electrode 4. It is preferable that the surface of the n-type layer 3 facing the photoelectric conversion layer 2 is in direct contact with the surface of the photoelectric conversion layer 2 facing the n-type layer 3. It is preferable that the n-type layer 3 is an amorphous thin film. The n-type layer 3 is preferably a metal oxide layer containing Zn and Si. The metal oxide layer (n-type layer 3) is preferably a layer composed of a compound represented by Zn x Si y M z O w , and x and y are 0.90≦x+y≦1.00. z satisfies 0.00≦z≦0.30, w satisfies 0.90≦w≦1.10, and M is selected from the group consisting of B, Al, Ga, In, and Ge. Preferably, it is one or more elements. Preferably, the metal oxide layer is substantially Zn x Si y M z O w except for unavoidable impurities. When x, y, z, and w are within these ranges, a good n-type layer is formed, and the conduction band positions of the Cu 2 O film and the n-type layer can be kept within a preferable range.
亜酸化銅を主体とする光電変換層２上に設けるｎ型層３としては、典型的には、ＺｎとＧｅの酸化物であるＺｎＧｅＯが用いられている。Ｇｅが高濃度含まれるＺｎＧｅＯ、例えば、Ｚｎ含有率よりもＧｅ含有率が高いＺｎＧｅＯ、より具体的には０．６≦（Ｇｅ[atom%]）／（Ｚｎ[atom%]＋Ｇｅ[atom%]）≦０．７程度のＧｅが含まれるＺｎＧｅＯは、亜酸化銅との伝導帯下端（Conduction Band Minimum：ＣＢＭ）差が少なく、高いフィルファクター（Fill Factor：ＦＦ）と高いＶｏｃが期待される。しかし、亜酸化銅を主体とする光電変換層２上にＺｎＧｅＯを成膜した太陽電池は、Ｖｏｃ及びＦＦが理論値と比べると低いため、高品質な光電変換層２を用いても変換効率の向上が期待した程度ではない。 As the n-type layer 3 provided on the photoelectric conversion layer 2 mainly made of cuprous oxide, ZnGeO, which is an oxide of Zn and Ge, is typically used. ZnGeO containing a high concentration of Ge, for example, ZnGeO with a Ge content higher than the Zn content, more specifically 0.6≦(Ge[atom%])/(Zn[atom%]+Ge[atom%] )≦0.7, ZnGeO has a small difference in conduction band minimum (CBM) from cuprous oxide, and is expected to have a high fill factor (FF) and high Voc. However, in a solar cell in which ZnGeO is deposited on a photoelectric conversion layer 2 mainly made of cuprous oxide, the Voc and FF are lower than the theoretical values, so even if a high-quality photoelectric conversion layer 2 is used, the conversion efficiency is low. The improvement was not as high as expected.
亜酸化銅を主体とする光電変換層２上に設けるｎ型層３としてＺｎ及びＳｉを含む金属酸化物層を用いることで、ＦＦ及びＶｏｃが向上し高い変換効率の太陽電池１００が得られる。ｎ型層３に含まれるＺｎの割合はＳｉの割合よりも多いことが好ましい。Ｓｉの含有率であるｙは、０．１０≦ｙ≦０．５０を満たすことが好ましい。Ｓｉの含有率が０．１０未満であると変換効率の増大幅が小さいため、つまりＣｕ２Ｏ層２とｎ型層３の間の伝導帯の差（Ｃｏｎｄｕｃｔｉｏｎ Ｂａｎｄ Ｏｆｆｓｅｔ）が大きいため好ましくない。また、Ｓｉの含有率が０．５より大きいとＺｎ以上にＳｉがＣｕ２Ｏ側に拡散してしまい、ｎ型層３とのｐｎ接合に影響を与えやすくなることが考えられる。加えて、ｙが０．５０より大きいことで、ｎ型層３の電気伝導性が失われやすくなり、絶縁体化してしまうため好ましくない。 By using a metal oxide layer containing Zn and Si as the n-type layer 3 provided on the photoelectric conversion layer 2 mainly made of cuprous oxide, a solar cell 100 with improved FF and Voc and high conversion efficiency can be obtained. It is preferable that the proportion of Zn contained in the n-type layer 3 is greater than the proportion of Si. It is preferable that y, which is the Si content, satisfies 0.10≦y≦0.50. If the Si content is less than 0.10, it is not preferable because the increase in conversion efficiency is small, that is, the difference in conduction band (Conduction Band Offset) between the Cu 2 O layer 2 and the n-type layer 3 is large. Furthermore, if the Si content is higher than 0.5, Si will diffuse to the Cu 2 O side more than Zn, and it is considered that the pn junction with the n-type layer 3 will be more likely to be affected. In addition, if y is larger than 0.50, the electrical conductivity of the n-type layer 3 is likely to be lost and the n-type layer 3 becomes an insulator, which is not preferable.
光電変換層２には、ＺｎとＳｉが微量含まれる。光電変換層２に含まれるＺｎの濃度は、光電変換層２に含まれるＳｉの濃度よりも高いことが好ましい。これはＣｕ２Ｏのｎ型層側の領域とｎ型層３とのｐｎ接合を良好にすることができるためである。光電変換層２に含まれるＺｎの濃度は、Ｓｉの濃度よりも３倍以上高いことがより好ましい。Ｚｎの濃度がＳｉの濃度よりも高い方が、ＦＦ及びＶｏｃが高くなるため上記関係を満たすことができるため、より好ましい。 The photoelectric conversion layer 2 contains trace amounts of Zn and Si. The concentration of Zn contained in the photoelectric conversion layer 2 is preferably higher than the concentration of Si contained in the photoelectric conversion layer 2. This is because the pn junction between the Cu 2 O region on the n-type layer side and the n-type layer 3 can be made good. It is more preferable that the concentration of Zn contained in the photoelectric conversion layer 2 is three times or more higher than the concentration of Si. It is more preferable that the Zn concentration is higher than the Si concentration because the above relationship can be satisfied since FF and Voc become higher.
光電変換層２において、Ｚｎは光電変換層２の深部（第１電極１側）にＳｉよりも多く存在していることが好ましい。光電変換層２のｎ型層３側の表面から第１電極１方向に向かって、例えば、６ｎｍまでの深さの領域において、光電変換層２のｎ型層３との界面側に微量のＺｎとＳｉが存在していることで、光電変換層２の性質がｎ型層３との良好なｐｎ接合になるように寄与している可能性がある。これらのＺｎとＳｉは、ｎ型層３から拡散したものでもよいし、光電変換層２の成膜中に意図的に微量添加されたものでもよい。より具体的には、光電変換層２とｎ型層３の界面（起点）から第１電極１方向に３ｎｍの深さ（終点）までの領域の平均Ｚｎ濃度を第１Ｚｎ濃度とし、光電変換層２とｎ型層３の界面から第１電極１方向に３ｎｍの深さ（起点）から第１電極１方向にさらに３ｎｍ深いところ（終点）までの領域の平均Ｚｎ濃度を第２Ｚｎ濃度とし、光電変換層２とｎ型層３の界面（起点）から第１電極１方向に３ｎｍの深さ（終点）までの領域の平均Ｓｉ濃度を第１Ｓｉ濃度とし、光電変換層２とｎ型層３の界面から第１電極１方向に３ｎｍの深さ（起点）から第１電極１方向にさらに３ｎｍ深いところ（終点）までの領域の平均Ｓｉ濃度を第２Ｓｉ濃度とする。このとき、［第１Ｚｎ濃度］＞［第１Ｓｉ濃度］、［第２Ｚｎ濃度］＞［第２Ｓｉ濃度］、［第１Ｚｎ濃度］＞［第２Ｚｎ濃度］及び［第１Ｓｉ濃度］＞［第２Ｓｉ濃度］を満たす。そして、３（［第１Ｚｎ濃度］／［第１Ｓｉ濃度］）≦（［第２Ｚｎ濃度］／［第２Ｓｉ濃度］）を満たすことがより好ましい。界面側と深部側を比較すると、界面側のＳｉ濃度に対するＺｎ濃度の比率よりも深部側のＳｉ濃度に対するＺｎ濃度の比率が３倍以上である（大きい）ことを表している。Ｚｎの方がＳｉよりも光電変換層２のより深部にまで拡散していることでｐｎ界面での再結合を抑制できるという利点がある。３（［第１Ｚｎ濃度］／［第１Ｓｉ濃度］）≦（［第２Ｚｎ濃度］／［第２Ｓｉ濃度］）のほうがよりｐｎ界面での再結合を抑制できるため、より好ましい。 In the photoelectric conversion layer 2, it is preferable that Zn exists in a larger amount than Si in the deep part of the photoelectric conversion layer 2 (on the first electrode 1 side). A trace amount of Zn is added to the interface side of the photoelectric conversion layer 2 with the n-type layer 3, for example, in a region up to 6 nm deep from the surface of the photoelectric conversion layer 2 on the n-type layer 3 side toward the first electrode 1. The presence of Si and Si may contribute to the properties of the photoelectric conversion layer 2 to form a good pn junction with the n-type layer 3. These Zn and Si may be those diffused from the n-type layer 3, or may be intentionally added in small amounts during film formation of the photoelectric conversion layer 2. More specifically, the average Zn concentration in the region from the interface (starting point) between the photoelectric conversion layer 2 and the n-type layer 3 to a depth of 3 nm (end point) in the direction of the first electrode 1 is defined as the first Zn concentration, and the photoelectric conversion layer The average Zn concentration in the region from the interface between 2 and the n-type layer 3 from a depth of 3 nm in the direction of the first electrode 1 (starting point) to a point further 3 nm deeper in the direction of the first electrode 1 (end point) is defined as the second Zn concentration. The average Si concentration in the region from the interface (starting point) between the conversion layer 2 and n-type layer 3 to a depth of 3 nm (end point) in the direction of the first electrode 1 is defined as the first Si concentration, and the average Si concentration of the photoelectric conversion layer 2 and n-type layer 3 is The average Si concentration in a region from a depth of 3 nm in the direction of the first electrode from the interface (starting point) to a point further 3 nm deeper in the direction of the first electrode (end point) is defined as the second Si concentration. At this time, [first Zn concentration] > [first Si concentration], [second Zn concentration] > [second Si concentration], [first Zn concentration] > [second Zn concentration] and [first Si concentration] > [second Si concentration] satisfy. It is more preferable that 3([first Zn concentration]/[first Si concentration])≦([second Zn concentration]/[second Si concentration]) be satisfied. Comparing the interface side and the deep side, it is shown that the ratio of the Zn concentration to the Si concentration on the deep side is three times or more (larger) than the ratio of the Zn concentration to the Si concentration on the interface side. Zn has the advantage that recombination at the pn interface can be suppressed because it is diffused deeper into the photoelectric conversion layer 2 than Si. 3([first Zn concentration]/[first Si concentration])≦([second Zn concentration]/[second Si concentration]) is more preferable because recombination at the pn interface can be further suppressed.
上記の濃度は、エネルギー分散型Ｘ線分光法（Energy Dispersive X-ray Spectroscopy；ＥＤＸ）で図１の模式図の方向の断面を切り出して、ｎ型層３側から光電変換層２に向かって走査して求める。光電変換層２とｎ型層３の境界（界面）もＥＤＸから求まる。光電変換層２とｎ型層３の境界は、次のようにして求める。ＥＤＸでＣｕ濃度とＺｎ濃度を測定し、ｎ型層３側からＣｕ濃度がＺｎ濃度以上になった最も第２電極４側の位置を境界とする。測定位置は、図２の分析スポットを説明する図に示すように太陽電池１００を第２電極４側から見た表面の９スポットＡ１～Ａ９を定める。各スポットは、正方形状で少なくとも５ｍｍ２の領域を有する。そして、図２に示すように、長さＤ１と幅Ｄ２（Ｄ１≧Ｄ２）とした場合、太陽電池１００の幅方向に対向する２辺からそれぞれ内側にＤ３（＝Ｄ１／１０）の距離のところに仮想線を引き、太陽電池１００の長さ方向に対向する２辺からそれぞれ内側にＤ４（＝Ｄ２／１０）の距離のところに仮想線を引き、さらに、太陽電池１００の中心を通る幅方向に平行な仮想線を引き、太陽電池１００の中心を通る長さ方向に平行な仮想線を引き、仮想線の交点９点を中心とする領域を観察スポットＡ１～Ａ９とする。ＳＥＭやＴＥＭによる観察断面は、図２の面に対して垂直方向である。なお、太陽電池１００を第２電極４側からみた形状が矩形ではない場合は、内接する矩形を基準に分析スポットを定めることが好ましい。濃度は、９点の分析スポットにおける値の最大値と最小値を除く７点の分析結果の平均値とする。 The above concentration was determined by cutting out a cross section in the direction of the schematic diagram in FIG. 1 using energy dispersive X-ray spectroscopy (EDX), and scanning from the n-type layer 3 side toward the photoelectric conversion layer 2. and ask. The boundary (interface) between the photoelectric conversion layer 2 and the n-type layer 3 is also determined from EDX. The boundary between the photoelectric conversion layer 2 and the n-type layer 3 is determined as follows. The Cu concentration and Zn concentration are measured by EDX, and the position closest to the second electrode 4 from the n-type layer 3 side where the Cu concentration becomes equal to or higher than the Zn concentration is defined as a boundary. As measurement positions, nine spots A1 to A9 are determined on the surface of the solar cell 100 when viewed from the second electrode 4 side, as shown in the diagram explaining the analysis spots in FIG. Each spot is square-shaped and has an area of at least 5 mm2 . As shown in FIG. 2, when the length is D1 and the width is D2 (D1≧D2), at a distance of D3 (=D1/10) inward from the two sides facing each other in the width direction of the solar cell 100. Draw an imaginary line at a distance of D4 (=D2/10) inward from the two sides facing each other in the length direction of the solar cell 100, and then draw an imaginary line in the width direction passing through the center of the solar cell 100. An imaginary line parallel to is drawn, an imaginary line parallel to the length direction passing through the center of the solar cell 100 is drawn, and areas centered at nine intersection points of the imaginary lines are defined as observation spots A1 to A9. The cross section observed by SEM or TEM is perpendicular to the plane of FIG. Note that when the solar cell 100 is not rectangular in shape when viewed from the second electrode 4 side, it is preferable to define the analysis spot based on the inscribed rectangle. The concentration is the average value of the analysis results of 7 points excluding the maximum and minimum values of the 9 analysis spots.
ｎ型層３の膜厚は、典型的には、３ｎｍ以上１００ｎｍ以下である。ｎ型層３の厚さが３ｎｍ未満であるとｎ型層３のカバレッジが悪い場合にリーク電流が発生し、特性を低下させてしまう場合がある。カバレッジが良い場合は上記膜厚に限定されない。ｎ型層３の厚さが５０ｎｍを超えるとｎ型層３の過度の高抵抗化による特性低下や、透過率低下による短絡電流低下が起こる場合がある。従って、ｎ型層３の厚さは３ｎｍ以上２０ｎｍ以下がより好ましく、５ｎｍ以上２０ｎｍ以下がさらにより好ましい。
このように、ｎ型層は薄いため、元素置換を行っても光学的な影響は小さいため、トップセルの透過率は主に光電変換層の膜質、例えばＣｕ２Ｏ膜質に依存し、良好なＣｕ２Ｏ層にｎ型層を適用することで高い透過率を維持し、ボトムセルの発電量を向上させることができる。その結果、トップセル効率とボトムセル効率を併せたタンデム効率として増大することが確認できる。
The thickness of the n-type layer 3 is typically 3 nm or more and 100 nm or less. If the thickness of the n-type layer 3 is less than 3 nm, leakage current may occur if the coverage of the n-type layer 3 is poor, and the characteristics may deteriorate. If the coverage is good, the film thickness is not limited to the above. If the thickness of the n-type layer 3 exceeds 50 nm, characteristics may deteriorate due to an excessively high resistance of the n-type layer 3, and short circuit current may decrease due to a decrease in transmittance. Therefore, the thickness of the n-type layer 3 is more preferably 3 nm or more and 20 nm or less, and even more preferably 5 nm or more and 20 nm or less.
In this way, since the n-type layer is thin, the optical effect is small even if element substitution is performed. Therefore, the transmittance of the top cell mainly depends on the film quality of the photoelectric conversion layer, for example, the Cu 2 O film quality, and a good By applying an n-type layer to the Cu 2 O layer, high transmittance can be maintained and the power generation amount of the bottom cell can be improved. As a result, it can be confirmed that the tandem efficiency increases as a combination of top cell efficiency and bottom cell efficiency.
ｎ型層３は、例えば、原子層堆積法（Atomic Layer Deposition；ＡＬＤ）やスパッタ法などで成膜することができる。 The n-type layer 3 can be formed by, for example, atomic layer deposition (ALD) or sputtering.
光電変換層２の伝導帯下端（Conduction Band Minimum：ＣＢＭ）の位置（Ｅｃｐ（ｅＶ））とｎ型層３の伝導帯下の位置（Ｅｃｎ（ｅＶ））の差である伝導帯オフセット（ΔＥ＝Ｅｃｐ－Ｅｃｎ）は、－０．２ｅＶ以上０．６ｅＶ以下（－０．２ｅＶ≦ΔＥ≦＋０．６ｅＶ）であることが好ましい。伝導帯オフセットが０より大きいとｐｎ接合界面の伝導帯が不連続となりスパイクが生じる。伝導帯オフセットが０より小さいとｐｎ接合界面の伝導帯が不連続となりクリフが生じる。スパイク及びクリフはどちらも光生成電子の障壁となるため小さい方が好ましい。従って、伝導帯オフセットは、０．０ｅＶ以上０．４ｅＶ以下（０．０ｅＶ≦ΔＥ≦＋０．４ｅＶ）であることがより好ましい。ただし、ギャップ内準位を利用して伝導する場合はこの限りではない。ＣＢＭの位置は、以下の手法を用いて見積もることができる。電子占有準位の評価法である光電子分光により価電子帯上端（Valence Band Maximum：ＶＢＭ）を実測し、続いて測定対象の材料のバンドギャップを仮定してＣＢＭを算出する。しかしながら、実際のｐｎ接合界面では、相互拡散や陽イオンの空孔発生など理想的な界面を維持していないため、バンドギャップが変化する可能性が高い。このため、ＣＢＭも直接的に光電子放出の逆過程を利用する逆光電子分光により評価することが好ましい。具体的には、太陽電池表面を低エネルギーイオンエッチングと正・逆光電子分光測定の繰り返しにより、ｐｎ接合界面の電子状態を評価できる。ｎ型層３のＺｎとＳｉの比率は、ＣＢＭの差を考慮して、上記好適な範囲内で適宜選択することができる。 Conduction band offset (ΔE= Ecp−Ecn) is preferably −0.2 eV or more and 0.6 eV or less (−0.2 eV≦ΔE≦+0.6 eV). If the conduction band offset is larger than 0, the conduction band at the p-n junction interface becomes discontinuous and a spike occurs. When the conduction band offset is smaller than 0, the conduction band at the p-n junction interface becomes discontinuous and a cliff occurs. Since both spikes and cliffs act as barriers to photogenerated electrons, it is preferable that they be smaller. Therefore, the conduction band offset is more preferably 0.0 eV or more and 0.4 eV or less (0.0 eV≦ΔE≦+0.4 eV). However, this is not the case when conduction is performed using the in-gap level. The location of the CBM can be estimated using the following technique. The valence band maximum (VBM) is actually measured by photoelectron spectroscopy, which is a method for evaluating the electron occupied level, and then the CBM is calculated assuming the band gap of the material to be measured. However, since an actual pn junction interface does not maintain an ideal interface due to mutual diffusion and cation vacancy generation, there is a high possibility that the band gap will change. For this reason, it is preferable to directly evaluate CBM by inverse photoelectron spectroscopy, which utilizes the inverse process of photoelectron emission. Specifically, the electronic state of the pn junction interface can be evaluated by repeatedly performing low-energy ion etching on the surface of the solar cell and performing forward and reverse photoelectron spectroscopy measurements. The ratio of Zn to Si in the n-type layer 3 can be appropriately selected within the above-mentioned preferred range, taking into consideration the difference in CBM.
第２電極４は、第１電極１で挙げた電極と同様の透明電極を用いることが好ましい。第２電極４としては他にも金属ワイヤーを含む取出電極が設けられた多層グラフェン等の他の透明電極を採用することもできる。必要に応じて第２電極４の上に金属の補助電極を堆積させてもよい。 As the second electrode 4, it is preferable to use a transparent electrode similar to the electrode mentioned for the first electrode 1. As the second electrode 4, other transparent electrodes such as multilayer graphene provided with extraction electrodes including metal wires can also be used. A metal auxiliary electrode may be deposited on the second electrode 4 if necessary.
（反射防止膜）
実施形態の反射防止膜は、光電変換層２へ光を導入しやすくするための膜であって、第１電極１上又は第２電極４上の光電変換層２側とは反対側に形成されていることが好ましい。反射防止膜としては、例えば、ＭｇＦ２やＳｉＯ２を用いることが望ましい。なお、実施形態において、反射防止膜を省くことができる。各層の屈折率に応じて膜厚を調整する必要があるが、７０～１３０ｎｍ（好ましくは、８０～１２０ｎｍ）程度の厚さの薄膜を蒸着することが好ましい。
(Anti-reflection film)
The antireflection film of the embodiment is a film that facilitates the introduction of light into the photoelectric conversion layer 2, and is formed on the first electrode 1 or the second electrode 4 on the side opposite to the photoelectric conversion layer 2 side. It is preferable that As the antireflection film, it is desirable to use, for example, MgF 2 or SiO 2 . Note that in the embodiment, the antireflection film can be omitted. Although it is necessary to adjust the film thickness according to the refractive index of each layer, it is preferable to deposit a thin film with a thickness of about 70 to 130 nm (preferably 80 to 120 nm).
（第２実施形態）
第２実施形態は、多接合型太陽電池に関する。図３に第２実施形態の多接合型太陽電池２００の断面概念図を示す。図３の多接合型太陽電池２００は、光入射側に第１実施形態の太陽電池（第１太陽電池）１００と、第２太陽電池２０１を有する。第２太陽電池２０１の光電変換層のバンドギャップは、第１実施形態の太陽電池１００の光電変換層２よりも小さいバンドギャップを有する。なお、実施形態の多接合型太陽電池は、３以上の太陽電池を接合させた太陽電池も含まれる。
(Second embodiment)
The second embodiment relates to a multijunction solar cell. FIG. 3 shows a conceptual cross-sectional diagram of a multijunction solar cell 200 according to the second embodiment. The multijunction solar cell 200 in FIG. 3 includes the solar cell (first solar cell) 100 of the first embodiment and the second solar cell 201 on the light incident side. The band gap of the photoelectric conversion layer of the second solar cell 201 is smaller than that of the photoelectric conversion layer 2 of the solar cell 100 of the first embodiment. Note that the multijunction solar cell of the embodiment also includes a solar cell in which three or more solar cells are joined together.
第１実施形態の太陽電池１００の光電変換層２のバンドギャップが約２．０ｅＶであるため、第２太陽電池２０１の光電変換層のバンドギャップは、１．０ｅＶ以上１．４ｅＶ以下であることが好ましい。第２太陽電池２０１の光電変換層としては、Ｉｎの含有比率が高いＣＩＧＳ系、ＣＩＴ系及びＣｄＴｅ系、酸化銅系のうちのいずれか１種以上の化合物半導体層又は結晶シリコンであることが好ましい。 Since the band gap of the photoelectric conversion layer 2 of the solar cell 100 of the first embodiment is approximately 2.0 eV, the band gap of the photoelectric conversion layer of the second solar cell 201 is 1.0 eV or more and 1.4 eV or less. is preferred. The photoelectric conversion layer of the second solar cell 201 is preferably a compound semiconductor layer of one or more of CIGS, CIT, CdTe, and copper oxide compounds having a high In content, or crystalline silicon. .
第１実施形態に係る太陽電池１００を第１太陽電池とすることで、第１太陽電池での意図しない波長域の光を吸収してしまうことによりボトムセル（第２太陽電池）の変換効率を低下させることを防ぐことができるので、効率の良い多接合型太陽電池とすることができる。 By using the solar cell 100 according to the first embodiment as the first solar cell, the conversion efficiency of the bottom cell (second solar cell) is reduced by absorbing light in an unintended wavelength range in the first solar cell. Since this can be prevented, a highly efficient multijunction solar cell can be obtained.
（第３実施形態）
第３実施形態は、太陽電池モジュールに関する。図４に第３実施形態の太陽電池モジュール３００の斜視概念図を示す。図４の太陽電池モジュール３００は、第１太陽電池モジュール３０１と第２太陽電池モジュール３０２を積層した太陽電池モジュールである。第１太陽電池モジュール３０１は、光入射側であり、第１実施形態の太陽電池１００を用いている。第２太陽電池モジュール３０２には、第２太陽電池２０１を用いることが好ましい。
(Third embodiment)
The third embodiment relates to a solar cell module. FIG. 4 shows a perspective conceptual diagram of a solar cell module 300 according to the third embodiment. A solar cell module 300 in FIG. 4 is a solar cell module in which a first solar cell module 301 and a second solar cell module 302 are stacked. The first solar cell module 301 is on the light incident side, and uses the solar cell 100 of the first embodiment. It is preferable to use the second solar cell 201 for the second solar cell module 302.
図５に太陽電池モジュール３００の断面概念図を示す。図５では、第１太陽電池モジュール３０１の構造を詳細に示し、第２太陽電池モジュール３０２の構造は示していない。第２太陽電池モジュール３０２では、用いる太陽電池の光電変換層などに応じて適宜、太陽電池モジュールの構造を選択する。図５の太陽電池モジュールは、複数の太陽電池１００（太陽電池セル）が横方向に並んで電気的に直列に接続した破線で囲われたサブモジュール３０３が複数含まれ、複数のサブモジュール３０３が電気的に並列もしくは直列に接続している。 FIG. 5 shows a cross-sectional conceptual diagram of the solar cell module 300. In FIG. 5, the structure of the first solar cell module 301 is shown in detail, and the structure of the second solar cell module 302 is not shown. In the second solar cell module 302, the structure of the solar cell module is appropriately selected depending on the photoelectric conversion layer of the solar cell to be used. The solar cell module in FIG. 5 includes a plurality of sub-modules 303 surrounded by broken lines in which a plurality of solar cells 100 (solar cells) are arranged horizontally and electrically connected in series. Electrically connected in parallel or series.
太陽電池１００は、スクライブされていて、隣り合う太陽電池１００は、上部側の第２電極４と下部側の第１電極１が接続している。第３実施形態の太陽電池１００も第１実施形態の太陽電池１００と同様に、基板１０、第１電極１、光電変換層２、ｎ型層３と第２電極４を有する。 The solar cells 100 are scribed, and the second electrode 4 on the upper side and the first electrode 1 on the lower side of adjacent solar cells 100 are connected. Similarly to the solar cell 100 of the first embodiment, the solar cell 100 of the third embodiment also includes a substrate 10, a first electrode 1, a photoelectric conversion layer 2, an n-type layer 3, and a second electrode 4.
モジュール毎に出力電圧が異なると電圧の低い部分に電流が逆流したり、余計な熱を発生させたりすることがあるためモジュールの出力低下につながる。 If the output voltage differs from module to module, current may flow backwards to parts with lower voltage or generate unnecessary heat, leading to a reduction in the module's output.
また、本願の太陽電池を用いると各波長帯に適した太陽電池を用いることができるため、トップセルやボトムセルの太陽電池を単体で用いたときと比較して効率良く発電できるようになり、モジュールの全体の出力が増大するため望ましい。 In addition, since the solar cell of the present application allows the use of solar cells suitable for each wavelength band, it is possible to generate electricity more efficiently than when using a top cell or bottom cell solar cell alone, and the module is desirable because it increases the overall output of
モジュール全体の変換効率が高いと、照射された光エネルギーのうち、熱になるエネルギー割合を低くすることができる。そのためモジュール全体の温度が上昇による効率の低下を抑制することができる。 When the conversion efficiency of the entire module is high, it is possible to reduce the proportion of energy converted into heat among the irradiated light energy. Therefore, it is possible to suppress a decrease in efficiency due to an increase in the temperature of the entire module.
（第４実施形態）
第４実施形態は太陽光発電システムに関する。第３実施形態の太陽電池モジュール３００は、第４実施形態の太陽光発電システムにおいて、発電を行う発電機として用いることができる。実施形態の太陽光発電システムは、太陽電池モジュールを用いて発電を行うものであって、具体的には、発電を行う太陽電池モジュールと、発電した電気を電力変換する手段と、発電した電気をためる蓄電手段又は発電した電気を消費する負荷とを有する。図６に実施形態の太陽光発電システム４００の構成概念図を示す。図６の太陽光発電システムは、太陽電池モジュール４０１（３００）と、電力変換装置４０２と、蓄電池４０３と、負荷４０４とを有する。蓄電池４０３と負荷４０４は、どちらか一方を省略しても良い。負荷４０４は、蓄電池４０３に蓄えられた電気エネルギーを利用することもできる構成にしてもよい。電力変換装置４０２は、変圧や直流交流変換などの電力変換を行う回路又は素子を含む装置である。電力変換装置４０２の構成は、発電電圧、蓄電池４０３や負荷４０４の構成に応じて好適な構成を採用すればよい。
(Fourth embodiment)
The fourth embodiment relates to a solar power generation system. The solar cell module 300 of the third embodiment can be used as a generator for generating electricity in the solar power generation system of the fourth embodiment. The solar power generation system of the embodiment generates power using a solar cell module, and specifically includes a solar cell module that generates power, a means for converting the generated electricity into power, and a means for converting the generated electricity into electric power. It has a storage means for accumulating electricity or a load for consuming the generated electricity. FIG. 6 shows a conceptual diagram of the configuration of a solar power generation system 400 according to an embodiment. The solar power generation system in FIG. 6 includes a solar cell module 401 (300), a power converter 402, a storage battery 403, and a load 404. Either one of the storage battery 403 and the load 404 may be omitted. The load 404 may also be configured to utilize electrical energy stored in the storage battery 403. The power conversion device 402 is a device that includes a circuit or an element that performs power conversion such as voltage transformation and DC/AC conversion. A suitable configuration for the power converter 402 may be adopted depending on the generated voltage and the configurations of the storage battery 403 and the load 404.
太陽電池モジュール３００に含まれる受光したサブモジュール３０１に含まれる太陽電池セルが発電し、その電気エネルギーは、コンバーター４０２で変換され、蓄電池４０３で蓄えられるか、負荷４０４で消費される。太陽電池モジュール４０１には、太陽電池モジュール４０１を常に太陽に向けるための太陽光追尾駆動装置を設けたり、太陽光を集光する集光体を設けたり、発電効率を向上させるための装置等を付加することが好ましい。 A solar cell included in a submodule 301 included in the solar cell module 300 that receives light generates electricity, and the electrical energy is converted by a converter 402 and stored in a storage battery 403 or consumed by a load 404 . The solar cell module 401 may be provided with a sunlight tracking drive device to always direct the solar cell module 401 toward the sun, a concentrator for concentrating sunlight, a device for improving power generation efficiency, etc. It is preferable to add.
太陽光発電システム４００は、住居、商業施設や工場などの不動産に用いられたり、車両、航空機や電子機器などの動産に用いられたりすることが好ましい。実施形態の変換効率に優れた太陽電池を太陽電池モジュール４０１に用いることで、発電量の増加が期待される。 The solar power generation system 400 is preferably used for real estate such as residences, commercial facilities, and factories, or for movable assets such as vehicles, aircraft, and electronic equipment. By using the solar cell with excellent conversion efficiency of the embodiment in the solar cell module 401, an increase in the amount of power generation is expected.
太陽光発電システム４００の利用例として車両を示す。図７に車両５００の構成概念図を示す。図７の車両５００は、車体５０１、太陽電池モジュール５０２、電力変換装置５０３、蓄電池５０４、モーター５０５とタイヤ（ホイール）５０６を有する。車体５０１の上部に設けられた太陽電池モジュール５０１で発電した電力は、電力変換装置５０３変換されて、蓄電池５０４にて充電されるか、モーター５０５等の負荷で電力が消費される。太陽電池モジュール５０１又は蓄電池５０４から供給される電力を用いてモーター５０５によってタイヤ（ホイール）５０６を回転させることにより車両５００を動かすことができる。太陽電池モジュール５０１としては、多接合型ではなく、第１実施形態の太陽電池１００を備えた第１太陽電池モジュールだけで構成されていてもよい。透過性のある太陽電池モジュール５０１を採用する場合は、車体５０１の上部に加え、車体５０１の側面に発電する窓として太陽電池モジュール５０１を使用することも好ましい。 A vehicle is shown as an example of how the solar power generation system 400 is used. FIG. 7 shows a conceptual diagram of the configuration of vehicle 500. Vehicle 500 in FIG. 7 includes a vehicle body 501, a solar cell module 502, a power converter 503, a storage battery 504, a motor 505, and tires (wheels) 506. Electric power generated by a solar cell module 501 provided on the upper part of a vehicle body 501 is converted by a power converter 503 and charged by a storage battery 504, or consumed by a load such as a motor 505. Vehicle 500 can be moved by rotating tires (wheels) 506 by motor 505 using electric power supplied from solar cell module 501 or storage battery 504 . The solar cell module 501 may not be a multi-junction type solar cell module but may be composed only of a first solar cell module including the solar cell 100 of the first embodiment. When employing a transparent solar cell module 501, it is also preferable to use the solar cell module 501 as a window for generating electricity on the side of the vehicle body 501 in addition to the top of the vehicle body 501.
以下、実施例に基づき本発明をより具体的に説明するが、本発明は以下の実施例に限定されるものではない。 EXAMPLES Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples.
（実施例１）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．９Ｓｉ０．１Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。
(Example 1)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.9 Si 0.1 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell.
ＡＭ１．５Ｇの光源を模擬したソーラーシミュレータを用い、その光源下で基準となるＳｉセルを用いて１ｓｕｎになるように光量を調節する。気温は２５℃とする。電圧をスイープし、電流密度（電流をセル面積で割ったもの）を測定する。横軸を電圧、縦軸を電流密度とした際に、横軸と交わる点が開放電圧Ｖｏｃとなり、縦軸と交わる点が短絡電流密度Ｊｓｃとなる。測定曲線上において、電圧と電流密度を掛け合わせ、最大になる点をそれぞれＶｍｐｐ、Ｊｍｐｐ（マキシマムパワーポイント）とすると、ＦＦ＝（Ｖｍｐｐ＊Ｊｍｐｐ）／（Ｖｏｃ＊Ｊｓｃ）
効率Ｅｆｆ．＝Ｖｏｃ＊Ｊｓｃ＊ＦＦで求まる。
Using a solar simulator that simulates an AM1.5G light source, the light intensity is adjusted to 1 sun using a reference Si cell under the light source. The temperature is 25°C. Sweep the voltage and measure the current density (current divided by cell area). When the horizontal axis is the voltage and the vertical axis is the current density, the point where it intersects with the horizontal axis is the open circuit voltage Voc, and the point where it intersects with the vertical axis is the short circuit current density Jsc. Multiply the voltage and current density on the measurement curve, and let the maximum points be Vmpp and Jmpp (maximum power point), respectively, then FF = (Vmpp * Jmpp) / (Voc * Jsc)
Efficiency Eff. It is determined by =Voc*Jsc*FF.
（実施例２）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．７Ｓｉ０．３Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 2)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.7 Si 0.3 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例３）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．５９Ｓｉ０．４１Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 3)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.59 Si 0.41 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例４）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．７Ｓｉ０．２５Ｂ０．０５Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 4)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.7 Si 0.25 B 0.05 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例５）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．７Ｓｉ０．２５Ａｌ０．０５Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 5)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.7 Si 0.25 Al 0.05 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例６）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．７Ｓｉ０．２５Ｇａ０．０５Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 6)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.7 Si 0.25 Ga 0.05 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例７）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．７Ｓｉ０．２０Ｉｎ０．１０Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 7)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.7 Si 0.20 In 0.10 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例８）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。亜酸化銅化合物の成膜の後半にＺｎとＳｉも一緒にスパッタする。その後、原子堆層積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．６Ｓｉ０．４Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。
(Example 8)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Zn and Si are also sputtered together in the latter half of the film formation of the cuprous oxide compound. Thereafter, n-type Zn 0.6 Si 0.4 O is deposited on the p-cuprous oxide layer by an atomic deposition method. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell.
（実施例９）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．９５Ｓｉ０．０５Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 9)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.95 Si 0.05 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例１０）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．５Ｓｉ０．５Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 10)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.5 Si 0.5 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例１１）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．５Ｇｅ０．３Ｓｉ０．２Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 11)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.5 Ge 0.3 Si 0.2 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（実施例１２）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．７Ｓｉ０．１Ａｌ０．２Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Example 12)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.7 Si 0.1 Al 0.2 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（比較例１）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．９５Ｇｅ０．０５Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Comparative example 1)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.95 Ge 0.05 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（比較例２）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．５Ｇｅ０．５Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Comparative example 2)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.5 Ge 0.5 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（比較例３）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．５Ｇｅ０．３Ｂ０．２Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Comparative example 3)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.5 Ge 0.3 B 0.2 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（比較例４）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．３Ｇｅ０．７Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Comparative example 4)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.3 Ge 0.7 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
（比較例５）
白板ガラス基板上に、裏面側の第１電極としてＩＴＯ透明導電膜、その上にＳｂドープしたＳｎＯ２透明導電膜を堆積する。透明な第１電極上に酸素とアルゴンガスの混合ガス雰囲気中でスパッタリング法により基板を４５０℃で加熱して亜酸化銅化合物を成膜する。その後、原子層堆積法によりｐ－亜酸化銅層上にｎ型のＺｎ０．７Ｇｅ０．２０Ｉｎ０．１０Ｏを堆積する。その後表面側の第２電極としてＡＺＯ透明導電膜を堆積する。その上に金属の補助電極を堆積させる。更に反射防止膜としてＭｇＦ２を堆積して太陽電池を得る。実施例１と同様に、変換効率、Ｖｏｃ及びＦＦを求める。
(Comparative example 5)
On a white glass substrate, an ITO transparent conductive film is deposited as a first electrode on the back side, and an Sb-doped SnO 2 transparent conductive film is deposited thereon. A cuprous oxide compound film is formed on the transparent first electrode by sputtering in a mixed gas atmosphere of oxygen and argon gas by heating the substrate at 450°C. Thereafter, n-type Zn 0.7 Ge 0.20 In 0.10 O is deposited on the p-cuprous oxide layer by atomic layer deposition. Thereafter, an AZO transparent conductive film is deposited as a second electrode on the front surface side. A metal auxiliary electrode is deposited thereon. Further, MgF 2 is deposited as an antireflection film to obtain a solar cell. As in Example 1, the conversion efficiency, Voc, and FF are determined.
表１に実施例及び比較例のＶｏｃ、ＦＦ及び変換効率をまとめて示す。Ｖｏｃは、比較例１のＶｏｃに対して＋０．１Ｖ以上である場合をＡと評価し、比較例１のＶｏｃに対して＋０Ｖ以上＋０．１Ｖ未満である場合をＢと評価し、比較例１のＶｏｃに対して＋０Ｖ未満である場合をＣと評価する。ＦＦは、比較例１のＦＦに対して、１．０３倍以上である場合をＡと評価し、比較例１のＦＦに対して１．００倍以上１．０３倍未満である場合をＢと評価して、比較例１のＦＦに対して１．００倍未満である場合をＣと評価する。変換効率は、比較例１の変換効率に対して１．１倍以上である場合をＡと評価し、比較例１の変換効率に対して１．０倍以上１．１倍未満である場合をＢと評価して、比較例１の変換効率に対して１．０倍未満である場合をＣと評価する。 Table 1 shows the Voc, FF, and conversion efficiency of Examples and Comparative Examples. Voc is evaluated as A when it is +0.1V or more with respect to the Voc of Comparative Example 1, and evaluated as B when it is +0V or more and less than +0.1V with respect to the Voc of Comparative Example 1. A case where the voltage is less than +0V with respect to Voc is evaluated as C. FF is evaluated as A when it is 1.03 times or more compared to the FF of Comparative Example 1, and B when it is 1.00 times or more and less than 1.03 times as compared to the FF of Comparative Example 1. When the FF is less than 1.00 times the FF of Comparative Example 1, it is evaluated as C. Conversion efficiency is evaluated as A when it is 1.1 times or more compared to the conversion efficiency of Comparative Example 1, and evaluated as A when it is 1.0 times or more and less than 1.1 times the conversion efficiency of Comparative Example 1. The conversion efficiency is evaluated as B, and the case where the conversion efficiency is less than 1.0 times that of Comparative Example 1 is evaluated as C.
実施例１－１１及び比較例１－５より、Ｓｉの比率が少なすぎると、伝導帯位置の差が大きく、Ｖｏｃが低くなり、Ｓｉの比率が多すぎると、ｎ型層の電気伝導性が失われやすくなり、ＦＦが下がることがわかる。このことから、適切なＳｉ比率のｎ型層を適用することで、高いＶｏｃとＦＦを得ることができることがわかる。実施例５，６，１２より、Ａｌ、ＧａはＶｏｃを高くする効果がある一方で多量に導入するとＦＦが下がる傾向があるため、適量導入することが望ましい。実施例７よりＩｎはＡｌ、Ｇａほどではないが、Ｖｏｃを高くする効果が見える。実施例１１よりＧｅは少量ではＶｏｃの増大幅が小さいものの、一定量を超えるとＶｏｃが大きくなる傾向が見える。実施例１０－１２は比較例と比較して、伝導帯オフセットの差が減少したため、Ｖｏｃの増大幅がさらに大きくなった。そのため、比較例よりも効率が改善していることがわかる。
明細書中、一部の元素は、元素記号のみで表している。
From Example 1-11 and Comparative Example 1-5, if the Si ratio is too small, the difference in conduction band position will be large and Voc will be low, and if the Si ratio is too large, the electrical conductivity of the n-type layer will be reduced. It can be seen that the FF becomes more likely to be lost and the FF decreases. This shows that high Voc and FF can be obtained by applying an n-type layer with an appropriate Si ratio. From Examples 5, 6, and 12, while Al and Ga have the effect of increasing Voc, if they are introduced in large amounts, they tend to lower the FF, so it is desirable to introduce them in appropriate amounts. From Example 7, it can be seen that In increases the Voc, although it is not as strong as Al and Ga. From Example 11, it can be seen that when Ge is used in a small amount, the increase in Voc is small, but when it exceeds a certain amount, Voc tends to increase. In Examples 10-12, the difference in conduction band offset decreased compared to the comparative example, so the increase in Voc became even larger. Therefore, it can be seen that the efficiency is improved compared to the comparative example.
In the specification, some elements are expressed only by element symbols.
以上、本発明の実施形態を説明したが、本発明は上記実施形態そのままに限定解釈されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記実施形態に開示されている複数の構成要素の適宜な組み合わせにより種々の発明を形成することができる。例えば、変形例の様に異なる実施形態にわたる構成要素を適宜組み合わせても良い。 Although the embodiments of the present invention have been described above, the present invention is not to be construed as limited to the above-described embodiments as they are, and in the implementation stage, the constituent elements can be modified and embodied without departing from the gist of the invention. Moreover, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiments. For example, components from different embodiments may be combined as appropriate as in a modified example.
１００…太陽電池（第１太陽電池、トップセル）、１…第１電極、２…光電変換層、３…ｎ型層、４…第２電極、２００…多接合型太陽電池、２０１…第２太陽電池（ボトムセル）、３００…太陽電池モジュール、３０１第１太陽電池モジュール、３０２…第２太陽電池モジュール、１０…基板、３０３…サブモジュール、４００…太陽光発電システム、４０１…太陽電池モジュール、４０２…電力変換装置、４０３…蓄電池、４０４…負荷、５００…車両、５０１…車体、５０２…太陽電池モジュール、５０３…電力変換装置、５０４…蓄電池、５０５…モーター、５０６…タイヤ（ホイール）
DESCRIPTION OF SYMBOLS 100... Solar cell (first solar cell, top cell), 1... First electrode, 2... Photoelectric conversion layer, 3... N-type layer, 4... Second electrode, 200... Multijunction solar cell, 201... Second Solar cell (bottom cell), 300...Solar cell module, 301 first solar cell module, 302...second solar cell module, 10...substrate, 303...submodule, 400...solar power generation system, 401...solar cell module, 402 ...Power converter, 403...Storage battery, 404...Load, 500...Vehicle, 501...Car body, 502...Solar cell module, 503...Power converter, 504...Storage battery, 505...Motor, 506...Tire (wheel)
Claims (7)
前記第１電極上に亜酸化銅を主体とする光電変換層と、
前記光電変換層上にＺｎ及びＳｉを含む金属酸化物層であるｎ型層と、
前記ｎ型層上に透明な第２電極とを有し、
前記金属酸化物層は、ＺｎｘＳｉｙＭｚＯｗで表される化合物で構成された層であり、
ｘ及びｙは、０．９０≦ｘ＋ｙ≦１．００を満たし、
前記ｙは、０．１０≦ｙ≦０．５０を満たし、
前記ｚは、０．００≦ｚ≦０．３０を満たし、
前記ｗは、０．９０≦ｗ≦１．１０を満たし、
前記Ｍは、Ｂ、Ａｌ、Ｇａ、Ｉｎ及びＧｅからなる群から選ばれる１種以上の元素であり、
前記光電変換層中に含まれるＺｎ濃度は、前記光電変換層中に含まれるＳｉ濃度よりも高い太陽電池。 a transparent first electrode;
a photoelectric conversion layer mainly made of cuprous oxide on the first electrode;
an n-type layer that is a metal oxide layer containing Zn and Si on the photoelectric conversion layer;
a transparent second electrode on the n-type layer;
The metal oxide layer is a layer composed of a compound represented by Zn x Si y M z O w ,
x and y satisfy 0.90≦x+y≦1.00,
The y satisfies 0.10≦y≦0.50,
The z satisfies 0.00≦z≦0.30,
The w satisfies 0.90≦w≦1.10,
The M is one or more elements selected from the group consisting of B, Al, Ga, In and Ge,
A solar cell in which the Zn concentration contained in the photoelectric conversion layer is higher than the Si concentration contained in the photoelectric conversion layer .
前記第１電極上に亜酸化銅を主体とする光電変換層と、 a photoelectric conversion layer mainly made of cuprous oxide on the first electrode;
前記光電変換層上にＺｎ及びＳｉを含む金属酸化物層であるｎ型層と、 an n-type layer that is a metal oxide layer containing Zn and Si on the photoelectric conversion layer;
前記ｎ型層上に透明な第２電極とを有し、 a transparent second electrode on the n-type layer;
前記金属酸化物層は、Ｚｎ The metal oxide layer is Zn ｘx ＳｉSi ｙy ＭM ｚz ＯO ｗlol で表される化合物で構成された層であり、It is a layer composed of a compound represented by
ｘ及びｙは、０．９０≦ｘ＋ｙ≦１．００を満たし、 x and y satisfy 0.90≦x+y≦1.00,
前記ｙは、０．１０≦ｙ≦０．５０を満たし、 The y satisfies 0.10≦y≦0.50,
前記ｚは、０．００≦ｚ≦０．３０を満たし、 The z satisfies 0.00≦z≦0.30,
前記ｗは、０．９０≦ｗ≦１．１０を満たし、 The w satisfies 0.90≦w≦1.10,
前記Ｍは、Ｂ、Ａｌ、Ｇａ、Ｉｎ及びＧｅからなる群から選ばれる１種以上の元素でり、 The M is one or more elements selected from the group consisting of B, Al, Ga, In and Ge,
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さまでの領域の平均Ｚｎ濃度を第１Ｚｎ濃度とし、 The average Zn concentration in a region from the interface between the photoelectric conversion layer and the n-type layer to a depth of 3 nm in the direction of the first electrode is defined as a first Zn concentration,
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さから前記第１電極の方向にさらに３ｎｍ深いところまでの領域の平均Ｚｎ濃度を第２Ｚｎ濃度とし、 The average Zn concentration in a region from a depth of 3 nm in the direction of the first electrode to a further 3 nm deeper in the direction of the first electrode from the interface between the photoelectric conversion layer and the n-type layer is defined as a second Zn concentration,
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さまでの領域の平均Ｓｉ濃度を第１Ｓｉ濃度とし、 The average Si concentration in a region from the interface between the photoelectric conversion layer and the n-type layer to a depth of 3 nm in the direction of the first electrode is defined as a first Si concentration,
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さから前記第１電極の方向にさらに３ｎｍ深いところまでの領域の平均Ｓｉ濃度を第２Ｓｉ濃度とし、 The average Si concentration in a region from a depth of 3 nm in the direction of the first electrode to a further 3 nm deeper in the direction of the first electrode from the interface between the photoelectric conversion layer and the n-type layer is defined as a second Si concentration,
前記第１Ｚｎ濃度、前記第２Ｚｎ濃度、前記第１Ｓｉ濃度及び前記第２Ｓｉ濃度は、［第１Ｚｎ濃度］＞［第１Ｓｉ濃度］、［第２Ｚｎ濃度］＞［第２Ｓｉ濃度］、［第１Ｚｎ濃度］＞［第２Ｚｎ濃度］及び［第１Ｓｉ濃度］＞［第２Ｓｉ濃度］を満たす太陽電池。 The first Zn concentration, the second Zn concentration, the first Si concentration, and the second Si concentration are such that [first Zn concentration]>[first Si concentration], [second Zn concentration]>[second Si concentration], and [first Zn concentration] > [Second Zn concentration] and [First Si concentration] > [Second Si concentration].
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さから前記第１電極の方向にさらに３ｎｍ深いところまでの領域の平均Ｚｎ濃度を第２Ｚｎ濃度とし、
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さまでの領域の平均Ｓｉ濃度を第１Ｓｉ濃度とし、
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さから前記第１電極の方向にさらに３ｎｍ深いところまでの領域の平均Ｓｉ濃度を第２Ｓｉ濃度とし、
前記第１Ｚｎ濃度、前記第２Ｚｎ濃度、前記第１Ｓｉ濃度及び前記第２Ｓｉ濃度は、［第１Ｚｎ濃度］＞［第１Ｓｉ濃度］、［第２Ｚｎ濃度］＞［第２Ｓｉ濃度］、［第１Ｚｎ濃度］＞［第２Ｚｎ濃度］及び［第１Ｓｉ濃度］＞［第２Ｓｉ濃度］を満たす請求項１に記載の太陽電池。 The average Zn concentration in a region from the interface between the photoelectric conversion layer and the n-type layer to a depth of 3 nm in the direction of the first electrode is defined as a first Zn concentration,
The average Zn concentration in a region from a depth of 3 nm in the direction of the first electrode to a further 3 nm deeper in the direction of the first electrode from the interface between the photoelectric conversion layer and the n-type layer is defined as a second Zn concentration,
The average Si concentration in a region from the interface between the photoelectric conversion layer and the n-type layer to a depth of 3 nm in the direction of the first electrode is defined as a first Si concentration,
The average Si concentration in a region from a depth of 3 nm in the direction of the first electrode to a further 3 nm deeper in the direction of the first electrode from the interface between the photoelectric conversion layer and the n-type layer is defined as a second Si concentration,
The first Zn concentration, the second Zn concentration, the first Si concentration, and the second Si concentration are such that [first Zn concentration]>[first Si concentration], [second Zn concentration]>[second Si concentration], and [first Zn concentration] The solar cell according to claim 1, which satisfies >[second Zn concentration] and [first Si concentration]>[second Si concentration].
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さから前記第１電極の方向にさらに３ｎｍ深いところまでの領域の平均Ｚｎ濃度を第２Ｚｎ濃度とし、
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さまでの領域の平均Ｓｉ濃度を第１Ｓｉ濃度とし、
前記光電変換層と前記ｎ型層の界面から前記第１電極の方向に３ｎｍの深さから前記第１電極の方向にさらに3ｎｍ深いところまでの領域の平均Ｓｉ濃度を第２Ｓｉ濃度とし、
前記第１Ｚｎ濃度、前記第２Ｚｎ濃度、前記第１Ｓｉ濃度及び前記第２Ｓｉ濃度は、３（［第１Ｚｎ濃度］／［第１Ｓｉ濃度］）≦（［第２Ｚｎ濃度］／［第２Ｓｉ濃度］）を満たす請求項１ないし３のいずれか１項に記載の太陽電池。 The average Zn concentration in a region from the interface between the photoelectric conversion layer and the n-type layer to a depth of 3 nm in the direction of the first electrode is defined as a first Zn concentration,
The average Zn concentration in a region from a depth of 3 nm in the direction of the first electrode to a further 3 nm deeper in the direction of the first electrode from the interface between the photoelectric conversion layer and the n-type layer is defined as a second Zn concentration,
The average Si concentration in a region from the interface between the photoelectric conversion layer and the n-type layer to a depth of 3 nm in the direction of the first electrode is defined as a first Si concentration,
The average Si concentration in a region from a depth of 3 nm in the direction of the first electrode to a further 3 nm deeper in the direction of the first electrode from the interface between the photoelectric conversion layer and the n-type layer is defined as a second Si concentration,
The first Zn concentration, the second Zn concentration, the first Si concentration, and the second Si concentration satisfy 3([first Zn concentration]/[first Si concentration])≦([second Zn concentration]/[second Si concentration]). The solar cell according to any one of claims 1 to 3, which satisfies the requirements of any one of claims 1 to 3.
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