JPH03272185A - Ultrahigh efficiency solar cell with tandem structure - Google Patents
Ultrahigh efficiency solar cell with tandem structureInfo
- Publication number
- JPH03272185A JPH03272185A JP2073951A JP7395190A JPH03272185A JP H03272185 A JPH03272185 A JP H03272185A JP 2073951 A JP2073951 A JP 2073951A JP 7395190 A JP7395190 A JP 7395190A JP H03272185 A JPH03272185 A JP H03272185A
- Authority
- JP
- Japan
- Prior art keywords
- solar cell
- compound semiconductor
- thin film
- semiconductor thin
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims abstract description 27
- 239000004065 semiconductor Substances 0.000 claims abstract description 25
- 239000010409 thin film Substances 0.000 claims abstract description 25
- 150000001875 compounds Chemical class 0.000 claims abstract description 24
- 229910001218 Gallium arsenide Inorganic materials 0.000 abstract description 13
- 239000010408 film Substances 0.000 abstract description 7
- -1 GaAs compound Chemical class 0.000 abstract description 3
- 238000000034 method Methods 0.000 abstract description 3
- 125000005842 heteroatom Chemical group 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 30
- 239000000463 material Substances 0.000 description 11
- 239000002019 doping agent Substances 0.000 description 9
- 239000000758 substrate Substances 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 230000003595 spectral effect Effects 0.000 description 4
- XCZXGTMEAKBVPV-UHFFFAOYSA-N trimethylgallium Chemical compound C[Ga](C)C XCZXGTMEAKBVPV-UHFFFAOYSA-N 0.000 description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- RBFQJDQYXXHULB-UHFFFAOYSA-N arsane Chemical compound [AsH3] RBFQJDQYXXHULB-UHFFFAOYSA-N 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- AXAZMDOAUQTMOW-UHFFFAOYSA-N dimethylzinc Chemical compound C[Zn]C AXAZMDOAUQTMOW-UHFFFAOYSA-N 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- XYFCBTPGUUZFHI-UHFFFAOYSA-N Phosphine Chemical compound P XYFCBTPGUUZFHI-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000002488 metal-organic chemical vapour deposition Methods 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 229910000059 tellane Inorganic materials 0.000 description 2
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 2
- 229910000070 arsenic hydride Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
この発明は、太陽光エネルギの光電変換効率を高めた超
高効率太陽電池に関するものであり、特に複数の太陽電
池を積み重ねたタンデム構造超高効率太陽電池に関する
ものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultra-high efficiency solar cell with improved photoelectric conversion efficiency of solar energy, and particularly relates to an ultra-high efficiency solar cell with a tandem structure in which a plurality of solar cells are stacked. It concerns efficient solar cells.
［従来の技術］
高い光電変換効率の太陽電池にする方法として、異なる
禁制帯幅を有する太陽電池を複数積層することが検討さ
れている。たとえば、ＧａＡｓ系太陽電池の上にＡｌＧ
ａＡｓ系太陽電池をヘテロ接合を介して積層し、タンデ
ム構造にすることが提案されている。また、ＧａＡｓ系
太陽電池とＧａ３ｂ系太陽電池とを機械的に接合し積層
してタンデム構造にすることも提案されている。[Prior Art] As a method for producing solar cells with high photoelectric conversion efficiency, stacking a plurality of solar cells having different forbidden band widths has been considered. For example, AlG on top of a GaAs solar cell.
It has been proposed to stack aAs solar cells via a heterojunction to form a tandem structure. It has also been proposed that a GaAs solar cell and a Ga3b solar cell be mechanically bonded and stacked to form a tandem structure.
太陽電池ではない単結晶シリコン基板上に、ＧａＡｓ系
太陽電池やＡＩＬＧａＡｓ系太陽電池をヘテロ接合を介
して積み重ねることは岡本等によって報告されている（
Ｐｒｏｃ、２０ｔｈ ＩＥＥＥ ＰＶｓｃ、 （
ＩＥＥＥ、Ｎｅｗ Ｙｏｒｋ。It has been reported by Okamoto et al. that GaAs solar cells and AIL GaAs solar cells can be stacked via heterojunctions on a single-crystal silicon substrate that is not a solar cell (
Proc, 20th IEEE PVsc, (
IEEE, New York.
１９８８））。また、ＧａＡｓ系太陽電池とＧａＡｓＰ
系太陽電池とを機械的に接合し積層したタンデム構造の
太陽電池は、ＦＲＡＡＳ等によって報告されている（Ｉ
ＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮ ＯＮ ＥＬＥ
ＣＴＯＲＯＮ ＤＥＶＩＣＥＳ Ｖｏｌ、３７
Ｎｏ、２１９９０ ｐ、４４３〜）。1988)). In addition, GaAs solar cells and GaAsP
Solar cells with a tandem structure, in which solar cells are mechanically bonded and stacked, have been reported by FRAAS and others (I
EEE TRANSACTION ON ELE
CTORON DEVICES Vol.37
No. 21990 p. 443~).
［発明が解決しようとする課題］
このようなタンデム型太陽電池であっても、たとえば、
地上で使用する太陽電池のように単位面積当たり非常に
高い変換効率が要求される太陽電池としては、変換効率
が低く、未だ不十分なものであった。[Problems to be solved by the invention] Even with such a tandem solar cell, for example,
The conversion efficiency was low and was still insufficient for solar cells that require extremely high conversion efficiency per unit area, such as solar cells used on the ground.
また、単結晶シリコン太陽電池の上に、ＧａＡＳ化合物
半導体薄膜の太陽電池を積層しようとする場合、単結晶
シリコンの格子定数とＧａＡｓの格子定数が大きく異な
るため、ヘテロ接合させることが難しく、超高効率の太
陽電池にすることができないという問題もあった。Furthermore, when trying to stack a GaAS compound semiconductor thin film solar cell on top of a single crystal silicon solar cell, the lattice constants of single crystal silicon and GaAs are very different, making it difficult to form a heterojunction. There was also the problem that it was impossible to make a highly efficient solar cell.
この発明の目的は、単結晶シリコン太陽電池の上に化合
物半導体薄膜太陽電池をヘテロ接合させ、タンデム構造
に積み重ねることによって、著しく光電変換効率の高め
られた太陽電池を提供することにある。An object of the present invention is to provide a solar cell with significantly increased photoelectric conversion efficiency by forming a heterojunction of a compound semiconductor thin film solar cell on a single crystal silicon solar cell and stacking the same in a tandem structure.
［課題を解決するための手段］
この発明のタンデム構造超高効率太陽電池は、単結晶シ
リコン太陽電池と、禁制帯幅が１．５７ｅＶ〜１．７３
ｅＶであるＧａＡｓ Ｐ化合物半導体薄膜からなる第１
の太陽電池と、禁制帯幅が２゜２３ｅＶ 〜２．２７ｅ
ＶであるＧａＡｓ Ｐ化合物半導体薄膜またはＧａＰ化
合物半導体薄膜からなる第２の太陽電池とを順次ヘテロ
接合によってタンデム構造に積み重ねたことを特徴とし
ている。[Means for Solving the Problems] The tandem structure ultra-high efficiency solar cell of the present invention has a monocrystalline silicon solar cell and a forbidden band width of 1.57 eV to 1.73 eV.
The first layer is made of a GaAs P compound semiconductor thin film with eV
solar cells and a forbidden band width of 2°23eV to 2.27e
It is characterized in that a second solar cell made of a GaAsP compound semiconductor thin film or a GaP compound semiconductor thin film, which is V, is stacked in a tandem structure through a heterojunction.
この発明において、第１の太陽電池の禁制帯幅を１．５
７ｅＶ〜１．７３ｅＶとし、第２の太陽電池の禁制帯幅
を２．２３ｅＶ〜２．２７ｅＶとしているのは、これら
の範囲からはずれると光電変換効率の低下が認められる
ためであり、これらの範囲を満足することにより最も優
れた光電変換効率を得ることができるからである。In this invention, the forbidden band width of the first solar cell is 1.5
The reason why the forbidden band width of the second solar cell is set to 7 eV to 1.73 eV and 2.23 eV to 2.27 eV is because a decrease in photoelectric conversion efficiency is recognized when it deviates from these ranges. This is because by satisfying the following, the most excellent photoelectric conversion efficiency can be obtained.
超高効率太陽電池とは、一般に３５％以上の光電変換効
率を示す太陽電池のことをいい、この発明は、このよう
な超高効率太陽電池としてさらに優れた光電変換効率を
有する太陽電池を提供するものである。An ultra-high efficiency solar cell generally refers to a solar cell that exhibits a photoelectric conversion efficiency of 35% or more, and the present invention provides a solar cell that has even better photoelectric conversion efficiency than such an ultra-high efficiency solar cell. It is something to do.
ＧａＡｓＰ化合物半導体の組成比を、ＧａＡｓ１−ＸＰ
ＸのＸの値で表わせば、Ｘが大きくなるにつれて、禁制
帯幅が大きくなる。このため、この発明においては、第
１の太陽電池のＸの値よりも、第２の太陽電池のＸの値
が大きくなる。さらに、第２の太陽電池においては、は
とんどＡ、 ｓが存在しない、すなわちＸが王であるよ
うなＧａＰの化合物半導体であってもよい。The composition ratio of the GaAsP compound semiconductor is changed to GaAs1-XP
Expressed by the value of X, the forbidden band width increases as X increases. Therefore, in the present invention, the value of X of the second solar cell is larger than the value of X of the first solar cell. Furthermore, the second solar cell may be a GaP compound semiconductor in which A and s are not present, that is, in which X is the king.
［作用］
太陽光は、広いスペクトル領域にわたっているので、単
一の材料を使った太陽電池では、吸収されて発電に利用
される光のスペクトル領域はこの太陽光のスペクトル領
域の一部であり、最大の変換効率を引き出すことは難し
い。吸収される光のスペクトルは、太陽電池として用い
る材料固有の禁制帯幅によって決まる。つまり、材料の
もつ禁制帯幅以下のエネルギをもった長波長光は、この
材料に吸収されず、短波長の光エネルギ内の禁制帯幅を
超える分については、有効に電気エネルギに変換されな
い。本発明者等は、このような観点から、禁制帯幅の異
なる材料で作製した太陽電池をタンデム構造に積層して
太陽光線の全ての領域にわたって有効に光エネルギを得
るためには、単結晶シリコン太陽電池の上にいかなる禁
制帯幅の材料からなる太陽電池を積層すべきかについて
、太陽光スペクトルの光エネルギと太陽電池の材料の禁
制帯幅およびこれらの吸収係数から計算を行なって予測
した。この結果を第３図に示す。第３図は、単結晶シリ
コン太陽電池の上に積み重ねられる第上の太陽電池の禁
制帯幅および第上の太陽電池の上に積み重ねられる第２
の太陽電池の禁制帯幅と光電変換効率との関係を示す図
である。この結果、単結晶シリコン（禁制帯幅１．１５
ｅＶの上に、禁制帯幅上、５７ｅＶ 〜１．７３ｅＶの
第１の太陽電池を積み重ね、この第１の太陽電池の上に
禁制帯幅２．２３ｅＶ〜２．２７ｅＶの第２の太陽電池
を積層することにより、光電変換効率の理論値として４
３％の値が得られることがわかった。[Operation] Sunlight covers a wide spectral range, so in a solar cell using a single material, the spectral range of the light that is absorbed and used for power generation is a part of the spectral range of sunlight. It is difficult to extract maximum conversion efficiency. The spectrum of light absorbed is determined by the inherent forbidden band width of the material used as the solar cell. In other words, long-wavelength light with energy less than the forbidden band width of the material is not absorbed by the material, and short-wavelength light energy that exceeds the forbidden band width is not effectively converted into electrical energy. From this point of view, the present inventors believe that in order to stack solar cells made of materials with different forbidden band widths in a tandem structure and effectively obtain light energy over the entire region of sunlight, single-crystal silicon should be used. What kind of forbidden band width should be used to stack the solar cell on top of the solar cell was calculated based on the light energy of the sunlight spectrum, the forbidden band width of the material of the solar cell, and their absorption coefficients. The results are shown in FIG. FIG. 3 shows the bandgap of a top solar cell stacked on top of a monocrystalline silicon solar cell and a second solar cell stacked on top of a single crystal silicon solar cell.
FIG. 2 is a diagram showing the relationship between the forbidden band width and photoelectric conversion efficiency of a solar cell. As a result, single crystal silicon (gap band width 1.15
eV, a first solar cell with a forbidden band width of 57 eV to 1.73 eV is stacked, and a second solar cell with a forbidden band width of 2.23 eV to 2.27 eV is stacked on top of this first solar cell. By stacking, the theoretical value of photoelectric conversion efficiency is 4.
It was found that a value of 3% was obtained.
そこで、本発明者等はこのような禁制帯幅を示す化合物
半導体薄膜としてＧａＡｓＰおよびＧａＰを用い、これ
らの材料からなる化合物半導体薄膜の太陽電池をシリコ
ン単結晶の太陽電池に積層したところ、これらのタンデ
ム型太陽電池が従来にはない優れた光電変換効率を示す
ことを見出した。Therefore, the present inventors used GaAsP and GaP as compound semiconductor thin films exhibiting such a forbidden band width, and stacked compound semiconductor thin film solar cells made of these materials on silicon single crystal solar cells. We have discovered that tandem solar cells exhibit an unprecedented photoelectric conversion efficiency.
また、この発明のタンデム構造太陽電池では、単結晶シ
リコン太陽電池の上にＧａＡｓＰ系の太陽電池を積層さ
せている。ＧａＡｓＰ系の太陽電池はシリコン単結晶と
格子定数が比較的近似しているため、直接成長させてヘ
テロ接合させても格子不整合が小さなものとなる。Furthermore, in the tandem structure solar cell of the present invention, a GaAsP solar cell is stacked on a single crystal silicon solar cell. GaAsP-based solar cells have a lattice constant that is relatively similar to that of silicon single crystals, so even if they are grown directly and formed into a heterojunction, the lattice mismatch will be small.
また、第２の太陽電池を構成する禁制帯幅の大きなＧａ
ＡｓＰおよびＧａＰは間接遷移型であるので、直接遷移
の材料に比べると、光スペクトルの吸収率が低い。そこ
で、ＧａＰの波長別の吸収係数を考慮して、この発明に
従う太陽電池における第１の太陽電池の厚みおよび第２
の太陽電池の厚みと光電変換効率との関係を計算し、第
４図に示した。第４図に示されるように、第２の太陽電
池の厚みが約８μｍで４２％、約２μｍで４１％、約１
μｍで４０％の光電変換効率が得られており、厚みが１
〜５μｍ程度で光電変換効率の理論値が４０％以上の太
陽電池を作製することのできることがわかった。In addition, Ga having a large forbidden band width constituting the second solar cell
Since AsP and GaP are indirect transition materials, their optical spectrum absorption is lower than that of direct transition materials. Therefore, considering the wavelength-specific absorption coefficient of GaP, the thickness of the first solar cell and the thickness of the second solar cell in the solar cell according to the present invention are
The relationship between the thickness of the solar cell and the photoelectric conversion efficiency was calculated and shown in Figure 4. As shown in FIG. 4, when the thickness of the second solar cell is about 8 μm, it is 42%, when it is about 2 μm, it is 41%, and about 1
A photoelectric conversion efficiency of 40% has been obtained in μm, and the thickness is 1
It was found that a solar cell with a theoretical value of photoelectric conversion efficiency of 40% or more can be produced with a thickness of about 5 μm.
［実施例］
実施例１
ボロンをドープしたＰ型単結晶シリコン基板表面に、Ｎ
型ドーパントとしてリンを熱拡散法で約０．３μｍ程度
拡散させて、Ｐ−Ｎ接合を形成し、単結晶シリコン太陽
電池を作製した。この太陽電池に電極をつけて、ソーラ
ーシミュレーターで光電変換効率を測定したところ工６
％であった。[Example] Example 1 N was applied to the surface of a P-type single crystal silicon substrate doped with boron.
Phosphorus was diffused as a type dopant by a thermal diffusion method to a depth of about 0.3 μm to form a PN junction, and a single crystal silicon solar cell was manufactured. Electrodes were attached to this solar cell and the photoelectric conversion efficiency was measured using a solar simulator.
%Met.
この太陽電池を用いてＯＭＶＰＥ法により、シリコン太
陽電池の上にＧａＡｓＰの化合物半導体を形成した。Ｇ
ａＡｓ１− ｘＰｘで示す組成化Ｘは０．２２であり、
禁制帯幅はＥｇ＝１．７０ｅ■であった。原料としては
アルシン（Ａ ｓ Ｈａ ）、ホスフィン（ＰＨ３）、
およびトリメチルガリウム（ＴＭＧａ）を用イテ、成長
温度を７００ ’Ｃ１成長速度を５μｍ／時間として成
長させた。ドーパントとしては、Ｐ型ＧａＡｓＰについ
てはジメチル亜鉛（ＤＭＺｎ）を用いてＺｎをドープし
、Ｎ９ＧａＡｓＰには水素化テルルを用いてＴｅをドー
プした。Using this solar cell, a GaAsP compound semiconductor was formed on the silicon solar cell by OMVPE. G
The composition X expressed as aAs1-xPx is 0.22,
The forbidden band width was Eg=1.70e■. Raw materials include arsine (A s Ha ), phosphine (PH3),
and trimethyl gallium (TMGa) at a growth temperature of 700'C1 and a growth rate of 5 μm/hour. As dopants, P-type GaAsP was doped with Zn using dimethylzinc (DMZn), and N9GaAsP was doped with Te using tellurium hydride.
第２の太陽電池としては、ＧａＡｓ１ ＋ ＸＰｘで示
す組成化Ｘが０．９５のＧａＡｓＰ化合物半導体薄膜を
形成した。この化合物半導体薄膜の禁制帯幅は、Ｅｇ＝
２．２４ｅＶであり、上記の第１の太陽電池のときと同
一の条件で成長させた。As the second solar cell, a GaAsP compound semiconductor thin film having a composition X of 0.95, expressed as GaAs1 + XPx, was formed. The forbidden band width of this compound semiconductor thin film is Eg=
The solar cell was grown under the same conditions as the first solar cell.
それぞれの太陽電池の間には王×１０１９ｃｍ−３の濃
度のＺｎを注入し、Ｐ“−ＧａＡｓＰ層を形成し、各太
陽電池の出力を取り出せるようにした。Zn was injected at a concentration of 10 cm -3 between each solar cell to form a P''-GaAsP layer, so that the output of each solar cell could be taken out.
第２の太陽電池であるＧａＡｓＰは間接遷移の領域にあ
り、光の吸収を十分に行ない禁制帯幅以上の短波長の光
を吸収して高効率を達成するためには、膜厚が５μｍ以
上必要であった。GaAsP, the second solar cell, is in the indirect transition region, and in order to achieve high efficiency by absorbing light with a short wavelength exceeding the forbidden band width, a film thickness of 5 μm or more is required. It was necessary.
また、最表面には、反射防止膜としてＴ ｉ ２０５を
蒸着法で形成した。Further, on the outermost surface, Ti 205 was formed as an antireflection film by vapor deposition.
第１図は、以上のようにして作製されたこの発明の一実
施例を示す断面図である。第１図を参照して、Ｐ型Ｓｉ
層ｌの上にはＮ型Ｓｉ層２が形成されており、これらに
より単結晶シリコン太陽型池７が構成されている。単結
晶シリコン太陽電池７の上にはＰ” −ＧａＡｓＰから
なる電極工０が形成され、この電極工０の上にＰ型Ｇａ
Ａｓ１−ＸＰＸ層３およびその上にＮ型ＧａＡｓ１−
ＸＰゆ層４ （ｘ＝０．２２）が形成されており、これ
らにより第２の太陽電池８が構成されている。この第２
の太陽電池８の上にＧａＡｓＩ−ｘＰｘからなる電極１
１が形成され、この上にＰ型ＧａＡｓ１− Ｘ ｐｘ層
５およびＮ型ＧａＡｓ１− ｘＰＸ層６ （ｘ＝０．９
５）が形成され、これらにより第２の太陽電池９が構成
されている。この第２の太陽電池９の上にＰ” −Ｇａ
ＡｓＰからなる電極１２が形成され、この電極１２の上
に反射防止膜１３としてのＴｉ２Ｏ５層が形成されてい
る。またこれらの太陽電池の底面であるＰ型Ｓｉ層ｌの
裏には裏面電極１４が形成されている。FIG. 1 is a sectional view showing an embodiment of the present invention manufactured as described above. Referring to FIG. 1, P-type Si
An N-type Si layer 2 is formed on the layer 1, and a single-crystal silicon solar pond 7 is constituted by these layers. An electrode work 0 made of P''-GaAsP is formed on the single crystal silicon solar cell 7, and a P-type GaAsP electrode work 0 is formed on the electrode work 0.
As1-XPX layer 3 and N-type GaAs1-
An XP layer 4 (x=0.22) is formed, and a second solar cell 8 is constituted by these layers. This second
An electrode 1 made of GaAsI-xPx is placed on the solar cell 8 of
1 is formed, and on top of this a P-type GaAs1-xpx layer 5 and an N-type GaAs1-xPx layer 6 (x=0.9
5) are formed, and the second solar cell 9 is constituted by these. P”-Ga on this second solar cell 9
An electrode 12 made of AsP is formed, and a Ti2O5 layer as an antireflection film 13 is formed on this electrode 12. Further, a back electrode 14 is formed on the back side of the P-type Si layer 1, which is the bottom surface of these solar cells.
このような太陽電池の光電変換効率をソーラーシミュレ
ータにより測定したところ、３８％であった。従来のＧ
ａＡｓ基板上にＡＬＧａＡｓ薄膜太陽電池をヘテロ接合
させたタンデム型太陽電池０
における変換効率が２４％であることを考慮すると、こ
の実施例１の太陽電池の光電変換効率は非常に高いもの
であった。When the photoelectric conversion efficiency of such a solar cell was measured using a solar simulator, it was 38%. conventional G
Taking into account that the conversion efficiency of a tandem solar cell made of a heterojunction of an ALGaAs thin film solar cell on an aAs substrate is 24%, the photoelectric conversion efficiency of the solar cell of Example 1 was extremely high. .
実施例２
上記の実施例１と同様の構成の太陽電池を、分子線エピ
タキシャル成長法（ＭＢＥ法）により単結晶シリコン太
陽電池の上に化合物半導体薄膜を成長させて作製した。Example 2 A solar cell having the same configuration as in Example 1 above was fabricated by growing a compound semiconductor thin film on a single crystal silicon solar cell by molecular beam epitaxial growth (MBE).
Ｐの材料としては、固体のＰを用い、ＧａＡｓの原料と
しては固体の金属材料を用いた。また、Ｐ型ＧａＡｓＰ
には金属Ｚｎを、Ｎ型ＧａＡｓＰにはＳｎをドーパント
として用いた。成長温度は３００℃とし、成長速度は１
μｍ／時間とした。Solid P was used as the material for P, and a solid metal material was used as the raw material for GaAs. In addition, P-type GaAsP
Metal Zn was used as a dopant for the dopant, and Sn was used as a dopant for the N-type GaAsP. The growth temperature was 300℃, and the growth rate was 1.
It was set as μm/hour.
得られたタンデム型太陽電池について、第１図と同様に
電極と反射防止膜を形成し、ソーラーシミュレータで光
電変換効率を測定したところ、３８％であった。Regarding the obtained tandem solar cell, an electrode and an antireflection film were formed in the same manner as in FIG. 1, and the photoelectric conversion efficiency was measured using a solar simulator, and it was found to be 38%.
実施例３
ボロンをドープしたＰ型車結晶シリコン基板の裏面に、
高濃度のボロンを熱拡散法で注入すると１
ともに、表面にはＮ型ドーパントとしてリンを０゜３μ
ｍ程度拡散させて、Ｐ−Ｎ接合を形成し、単結晶シリコ
ン太陽電池を作製した。これに電極をつけて、ソーラー
シミュレータで光電変換率を測定したところ、１６％で
あった。Example 3 On the back side of a P-type wheel crystal silicon substrate doped with boron,
Highly concentrated boron was implanted using the thermal diffusion method, and 0.3 μm of phosphorus was added to the surface as an N-type dopant.
A single crystal silicon solar cell was produced by diffusing the mixture by about m to form a PN junction. When electrodes were attached to this and the photoelectric conversion rate was measured using a solar simulator, it was 16%.
これを基板として用い、この上にＯＭＶＰＥ法によりＧ
ａＡｓＰ太陽電池を形成し、さらにこの上にＧａＰ太陽
電池を形成してタンデム型化合物薄膜太陽電池を作製し
た。原料としては、アルシン（ＡｓＨ３）、ホスフィン
（ＰＨ３）およびトリメチルガリウム（ＴＭＧａ）を用
い、成長温度は６００℃とし、成長速度は５μｍ／時間
として成長させた。第１の太陽電池であるＧａＡｓＰと
第２の太陽電池であるＧａＰは同じ条件で成長させた。Using this as a substrate, G
A tandem compound thin film solar cell was fabricated by forming an aAsP solar cell and further forming a GaP solar cell thereon. Arsine (AsH3), phosphine (PH3), and trimethyl gallium (TMGa) were used as raw materials, the growth temperature was 600°C, and the growth rate was 5 μm/hour. The first solar cell, GaAsP, and the second solar cell, GaP, were grown under the same conditions.
ドーパントとしては、Ｐ型にはジメチル亜鉛（Ｄ Ｍ
Ｚ ｎ、 ）を用いてＺｎをドープし、Ｎ型には水素化
テルルを用いてＴｅをドープした。As a dopant, dimethylzinc (DM
Zn was doped using Z n, ), and Te was doped using tellurium hydride for the N type.
各太陽電池の間ならびに単結晶シリコンの裏面およびＧ
ａＰ太陽電池の表面には、１×１０１１０１９’の濃度
のＺｎを注入して、Ｐ″″−ＧａＡｓ Ｐ２
層を形成し、太陽電池の出力を取り出すための電極とし
た。Between each solar cell and the back side of single crystal silicon and G
Zn was injected into the surface of the aP solar cell at a concentration of 1 x 1011019' to form a P''''-GaAs P2 layer, which served as an electrode for extracting the output of the solar cell.
第２図は、以上のようにして作製されたこの発明の他の
実施例を示す断面図である。第１図を参照して、単結晶
シリコン太陽電池２７は、Ｐ型Ｓｉ層２王およびその上
のＮ型Ｓｉ層２２から構成されており、この単結晶シリ
コン太陽電池２７の上には電極１１としてのＰ” −Ｇ
ａＡｓＰ層が形成されている。FIG. 2 is a sectional view showing another embodiment of the present invention manufactured as described above. Referring to FIG. 1, a single crystal silicon solar cell 27 is composed of a P-type Si layer 2 and an N-type Si layer 22 thereon. P”-G as
An aAsP layer is formed.
この上には第２の太陽電池２８としてのＧａＡｓＰ化合
物半導体薄膜太陽電池を構成する、Ｐ型ＧａＡｓ Ｐ層
２３およびその上のＮ型ＧａＡｓＰ層２４が形成されて
おり、さらにその上には電極３１としてのＰ” −Ｇａ
ＡｓＰ層が形成されている。On top of this, a P-type GaAs P layer 23 and an N-type GaAsP layer 24 thereon are formed, which constitute a GaAsP compound semiconductor thin film solar cell as a second solar cell 28, and further on top of this, an electrode 31 is formed. P”-Ga as
An AsP layer is formed.
この上には、さらに、第２の太陽電池２９としてのＧａ
Ｐ化合物半導体薄膜太陽電池を構成する、Ｐ型ＧａＰ層
２５およびその上のＮ型ＧａＰ層２６が形成されており
、その上には電極３２としてのＰ“−ＧａＡｓＰ層が形
成され、さらにその上３
にはＴｉ２Ｏ５からなる反射防止膜３３が形成されてい
る。On top of this, there is further a Ga as a second solar cell 29.
A P-type GaP layer 25 and an N-type GaP layer 26 thereon are formed, which constitute a P compound semiconductor thin film solar cell, and a P"-GaAsP layer as an electrode 32 is formed on top of the P-type GaP layer 25. 3, an antireflection film 33 made of Ti2O5 is formed.
以上のようにして得られた太陽電池の光電変換効率をソ
ーラシミュレータにより測定したところ、３８％であっ
た。The photoelectric conversion efficiency of the solar cell obtained as described above was measured using a solar simulator and was found to be 38%.
実施例４
上記の実施例３で使用した単結晶シリコン太陽電池を基
板に用いて、分子線エピタキシャル成長法により第１の
太陽電池としてのＧａＡｓ Ｐ薄膜太陽電池およびその
上の第２の太陽電池としてのＧａＰ太陽電池を成長させ
た。材料としては固体蒸発源を用いた。Ｐ型ドーパント
には金属Ｚｎを用い、Ｎ型ドーパントにはＳｎを用いた
。成長温度は３００℃とし、成長速度は１μｍ／時間と
した。Example 4 Using the single crystal silicon solar cell used in Example 3 above as a substrate, a GaAs P thin film solar cell as a first solar cell and a second solar cell thereon were grown by molecular beam epitaxial growth. GaP solar cells were grown. A solid evaporation source was used as the material. Metal Zn was used as the P-type dopant, and Sn was used as the N-type dopant. The growth temperature was 300° C. and the growth rate was 1 μm/hour.
得られたタンデム型太陽電池について、実施例３と同様
にして電極および反射防止膜を形成してソーラシミュレ
ータで光電変換効率を測定したところ３８％であった。Regarding the obtained tandem solar cell, an electrode and an antireflection film were formed in the same manner as in Example 3, and the photoelectric conversion efficiency was measured using a solar simulator and found to be 38%.
第１の太陽電池の禁制帯幅を１．５７ｅＶ〜１゜工４
７３ｅＶの範囲内で、第２の太陽電池の禁制帯幅を２．
２３ｅｖ〜２°２７ｅＶの範囲内で変化させて、種々の
他の太陽電池を作製し、ソーラシミュレータで上記の各
実施例と同様に光電変換効率を測定したところ、いずれ
も約３８％の値を示し、この発明に従うタンデム構造超
高効率太陽電池は、優れた光電変換効率を示すことが確
認された。The forbidden band width of the first solar cell is set within the range of 1.57 eV to 1° 473 eV, and the forbidden band width of the second solar cell is set within the range of 2.
Various other solar cells were produced by changing the voltage within the range of 23ev to 2°27eV, and the photoelectric conversion efficiency was measured using a solar simulator in the same manner as in each of the above examples. It was confirmed that the tandem structure ultra-high efficiency solar cell according to the present invention exhibits excellent photoelectric conversion efficiency.
また、上記の実施例１および３においてはＯＭＶＰＥ法
により化合物半導体薄膜を成長させているが、キセノン
ランプ等のフラッシュ光を照射しながら熱分解を行なう
光ＣＶＤ法を用いることにより、より低温で成長するこ
とができるようになる。このように、より低温で成長さ
せることにより、単結晶シリコンとＧａＡｓＰやＧａＰ
との熱膨脂係数の違いによる応力を低くすることができ
、ざらに光電変換効率を向上させることができる。In addition, in Examples 1 and 3 above, the compound semiconductor thin film was grown by the OMVPE method, but by using the photoCVD method, which performs thermal decomposition while irradiating flash light from a xenon lamp, it is possible to grow the compound semiconductor thin film at a lower temperature. You will be able to do this. In this way, by growing at a lower temperature, single crystal silicon, GaAsP, and GaP can be grown.
It is possible to reduce the stress caused by the difference in thermal expansion coefficient between the two and the photoelectric conversion efficiency.
［発明の効果］
以上説明したように、この発明のタンデム構造超高効率
太陽電池では、太陽光のスペクトル領域においてそのエ
ネルギを最大限に吸収することが５
でき、従来の太陽電池に比べ、光電変換効率を著しく向
上させることができる。[Effects of the Invention] As explained above, the tandem structure ultra-high-efficiency solar cell of the present invention can absorb the maximum amount of energy in the spectral region of sunlight5, and has a higher photovoltaic power than conventional solar cells. Conversion efficiency can be significantly improved.
第１図は、この発明の一実施例を示す断面図である。
第２図は、この発明の他の実施例を示す断面図である。
第３図は、単結晶シリコン太陽電池の上に積み重ねられ
る第１の太陽電池の禁制帯幅および第１の太陽電池の上
に積み重ねられる第２の太陽電池の禁制帯幅と光電変換
率との関係を示す図である。
第４図は、単結晶シリコン太陽電池の上に積み重ねられ
る第１の太陽電池の厚みおよび第１の太陽電池の上に積
み重ねられる第２の太陽電池の厚みと光電変換効率との
関係を示す図である。
図において、７は単結晶シリコン太陽電池、８は第１の
太陽電池、９は第２の太陽電池、２７は単結晶シリコン
太陽電池、２８は第１の太陽電池、２９は第２の太陽電
池を示す。
６FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is a sectional view showing another embodiment of the invention. FIG. 3 shows the photoelectric conversion rate versus the forbidden band width of a first solar cell stacked on top of a single crystal silicon solar cell and the forbidden band width of a second solar cell stacked on top of the first solar cell. It is a figure showing a relationship. FIG. 4 is a diagram showing the relationship between the thickness of a first solar cell stacked on a single crystal silicon solar cell, the thickness of a second solar cell stacked on the first solar cell, and photoelectric conversion efficiency. It is. In the figure, 7 is a single crystal silicon solar cell, 8 is a first solar cell, 9 is a second solar cell, 27 is a single crystal silicon solar cell, 28 is a first solar cell, and 29 is a second solar cell. shows. 6
Claims (1)
ｅＶ〜１．７３ｅＶであるＧａＡｓＰ化合物半導体薄膜
からなる第１の太陽電池と、禁制帯幅が２．２３ｅＶ〜
２．２７ｅＶであるＧａＡｓＰ化合物半導体薄膜または
ＧａＰ化合物半導体薄膜からなる第２の太陽電池とを順
次ヘテロ接合によってタンデム構造に積み重ねたことを
特徴とする、タンデム構造超高効率太陽電池。(1) Single crystal silicon solar cell and forbidden band width of 1.57
A first solar cell made of a GaAsP compound semiconductor thin film with a voltage of eV ~ 1.73 eV and a forbidden band width of ~ 2.23 eV.
A tandem structure ultra-high efficiency solar cell characterized in that a GaAsP compound semiconductor thin film having a voltage of 2.27 eV or a second solar cell made of a GaP compound semiconductor thin film are sequentially stacked in a tandem structure by a heterojunction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2073951A JPH03272185A (en) | 1990-03-22 | 1990-03-22 | Ultrahigh efficiency solar cell with tandem structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2073951A JPH03272185A (en) | 1990-03-22 | 1990-03-22 | Ultrahigh efficiency solar cell with tandem structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03272185A true JPH03272185A (en) | 1991-12-03 |
Family
ID=13532902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2073951A Pending JPH03272185A (en) | 1990-03-22 | 1990-03-22 | Ultrahigh efficiency solar cell with tandem structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03272185A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019116665A1 (en) * | 2017-12-14 | 2019-06-20 | 株式会社カネカ | Photoelectric conversion element and photoelectric conversion device |
-
1990
- 1990-03-22 JP JP2073951A patent/JPH03272185A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019116665A1 (en) * | 2017-12-14 | 2019-06-20 | 株式会社カネカ | Photoelectric conversion element and photoelectric conversion device |
| JPWO2019116665A1 (en) * | 2017-12-14 | 2020-12-17 | 株式会社カネカ | Photoelectric conversion element and photoelectric conversion device |
| US10962411B2 (en) | 2017-12-14 | 2021-03-30 | Kaneka Corporation | Photoelectric conversion element and photoelectric conversion device |
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