JPH03285368A - Gaas solar cell - Google Patents
Gaas solar cellInfo
- Publication number
- JPH03285368A JPH03285368A JP2087797A JP8779790A JPH03285368A JP H03285368 A JPH03285368 A JP H03285368A JP 2087797 A JP2087797 A JP 2087797A JP 8779790 A JP8779790 A JP 8779790A JP H03285368 A JPH03285368 A JP H03285368A
- Authority
- JP
- Japan
- Prior art keywords
- epitaxial layer
- type
- layer
- solar cell
- gaas
- 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.)
- Granted
Links
- 229910001218 Gallium arsenide Inorganic materials 0.000 claims abstract description 62
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 24
- 239000000758 substrate Substances 0.000 claims abstract description 14
- 239000002019 doping agent Substances 0.000 claims abstract description 7
- 125000002524 organometallic group Chemical group 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 6
- XCZXGTMEAKBVPV-UHFFFAOYSA-N trimethylgallium Chemical compound C[Ga](C)C XCZXGTMEAKBVPV-UHFFFAOYSA-N 0.000 claims description 6
- 238000000927 vapour-phase epitaxy Methods 0.000 claims description 4
- RGGPNXQUMRMPRA-UHFFFAOYSA-N triethylgallium Chemical compound CC[Ga](CC)CC RGGPNXQUMRMPRA-UHFFFAOYSA-N 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 abstract description 13
- 239000000463 material Substances 0.000 abstract description 10
- 230000003449 preventive effect Effects 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 75
- 238000000034 method Methods 0.000 description 8
- 238000002488 metal-organic chemical vapour deposition Methods 0.000 description 6
- 238000009826 distribution Methods 0.000 description 5
- 238000009792 diffusion process Methods 0.000 description 4
- 239000000969 carrier Substances 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 241000238557 Decapoda Species 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 235000015278 beef Nutrition 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- PZPGRFITIJYNEJ-UHFFFAOYSA-N disilane Chemical compound [SiH3][SiH3] PZPGRFITIJYNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000006467 substitution reaction Methods 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］
本発明は太陽電池、特にＧａＡｓ系のエビタ牛ンヤル層
を有する太陽電池に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a solar cell, and particularly to a solar cell having a GaAs layer.
［従来の技術］
ＧａＡｓ系を用いた太陽電池は、ＧａＡｓの禁制帯幅が
１．４３ｅＶと大きく、太陽電池の理想とされるｌ、５
ｅＶに近いことから、ＳｌやＩｎＰなど他の多くの太陽
電池の中でも最も高い変換効率を示す。その構造の代表
的な例を第２図に示す。[Prior art] Solar cells using GaAs have a large forbidden band width of 1.43 eV, which is considered to be the ideal solar cell.
Since it is close to eV, it has the highest conversion efficiency among many other solar cells such as Sl and InP. A typical example of its structure is shown in FIG.
ｎ型ＧａＡｓ基板１上にｎ型ＧａＡｓ！ビタキシャル層
、ｐ型ＧａＡｓエピタキシャル層を順次エピタキシャル
成長し、その上に表面電極５とｐ型ＧａＡ１２Ａｓエビ
タキン＋ル層４を形成し、さらに反射防止Ｍ６を設けて
いる。入射した太陽光によって発生した光起電力はｐ型
ＧａＡｓエビタ牛シャル層３上に形成された表面電極５
と基板ｌ下に設けた裏面電極７を通じて取り出される。n-type GaAs on the n-type GaAs substrate 1! A bitaxial layer and a p-type GaAs epitaxial layer are sequentially epitaxially grown, and a surface electrode 5 and a p-type GaA12As epitaxial layer 4 are formed thereon, and an anti-reflection layer M6 is further provided. The photovoltaic force generated by the incident sunlight is transferred to the surface electrode 5 formed on the p-type GaAs layer 3.
and is taken out through the back electrode 7 provided under the substrate l.
ところで、ｐ型ＧａＡｓエピタキシャル層３の表面には
不飽和結合（ダングリングボンド）による表面単位が高
密度で存在し、発生したキャリアが表面電極５に取り込
まれる荊に表面で再結合し、エネルギの変換効率が著し
く低下する。Incidentally, surface units formed by unsaturated bonds (dangling bonds) exist at a high density on the surface of the p-type GaAs epitaxial layer 3, and the generated carriers recombine on the surface with the dangling bonds taken into the surface electrode 5, and the energy is released. Conversion efficiency decreases significantly.
そこで表面単位密度を低下し、表面へのキャリア流出を
防ぐ目的でｐ型ＧａＡｓエピタキシャル層３の上に上記
したｐ型ＧａＡ（！Ａｓエピタキシャル層４を窓材とし
て設ける構造がとられている。Therefore, in order to reduce the surface unit density and prevent carriers from flowing out to the surface, a structure is adopted in which the above-mentioned p-type GaA(!As epitaxial layer 4 is provided as a window material) on the p-type GaAs epitaxial layer 3.
また、この窓材となるＧａＡ（Ａｓエピタキシャル層４
の保護及び入射光の反射を極力少なくすることを目的と
して、ＧａＡ（Ａｓエピタキシャル層層上上太陽光に対
して透明かつ耐久性のあるシリコンナイトライド（ＳＩ
３Ｎ４）等の材質からなる上記した反射防止膜６が設け
られる。In addition, a GaA (As epitaxial layer 4) is used as the window material.
Silicon nitride (SI), which is transparent and durable to sunlight, was added on top of the GaA (As) epitaxial layer to protect it and minimize the reflection of incident light.
The above-mentioned antireflection film 6 made of a material such as 3N4) is provided.
これにより、変換効率２０％以上のＧａＡｓ太陽電池が
得られている。As a result, a GaAs solar cell with a conversion efficiency of 20% or more has been obtained.
このようなＧａＡｓ系太陽電池において、従来ｐ型エピ
タ牛シャル層形成のためのドーパントとしてはＺｎＳＢ
ｅ等が専ら用いられている。In such GaAs solar cells, ZnSB has conventionally been used as a dopant for forming a p-type epitaxial layer.
e etc. are exclusively used.
［発明が解決しようとする課題］
ところで、太陽電池のエネルギ変換効率の向上を図る上
で重要な点は、短絡電流密度１ｓｃと開放電圧Ｖｏｃの
他に、曲線因子ＦＦの改善が上げられる。[Problems to be Solved by the Invention] By the way, in addition to short circuit current density 1sc and open circuit voltage Voc, an important point in improving the energy conversion efficiency of a solar cell is improvement of fill factor FF.
曲線因子ＦＦはダイオード特性や並列抵抗、直列抵抗に
関係しているか、特に直列抵抗の大きさには大きく依存
し、トータルとしての変換効率向上にはこれらの最適な
設計が必要である。The fill factor FF is related to the diode characteristics, parallel resistance, and series resistance, and in particular, it greatly depends on the magnitude of the series resistance, and an optimal design of these is necessary to improve the total conversion efficiency.
すなわち、第２図の太陽電池において、表面電極５の面
積を増加し、ｐ型ＧａＡｓエピタキシャル層３のキャリ
ア濃度を増加することは直列抵抗の低減に役立ち、曲性
因子ＦＦの改善につながる。That is, in the solar cell of FIG. 2, increasing the area of the surface electrode 5 and increasing the carrier concentration of the p-type GaAs epitaxial layer 3 helps to reduce the series resistance, leading to an improvement in the curvature factor FF.
しかし、一方で、表面電極５の増加は、電極の影による
影損失の増加を招き、またｐ型ＧａＡｓエピタキシャル
層３のキャリア濃度増加は発生キャリアのｐ型ＧａＡｓ
エピタキシャル層３内での再結合確率を助長し、短絡電
流密度１ｏｃを下げるという結果を招く。However, on the other hand, the increase in the number of surface electrodes 5 causes an increase in shadow loss due to the shadow of the electrodes, and the increase in the carrier concentration in the p-type GaAs epitaxial layer 3 causes the p-type GaAs of the generated carriers to increase.
This increases the recombination probability within the epitaxial layer 3, resulting in a lower short circuit current density 1oc.
従って、変換効率を向上するにはｐ型ＧａＡｓエピタキ
シャル層３内のキャリア濃度分布を適正にする必要があ
るが、従来用いているｐ型ドーパント元素であるＺｎＳ
Ｂｅ等はＧａＡｓ結晶中のでの拡散係数が大きく、適正
な分布か得られないばかりでなく、キャリア濃度を５Ｘ
ＩＯ”ｃｍ以上の高濃度にすることが非常に困難であっ
た。Therefore, in order to improve the conversion efficiency, it is necessary to make the carrier concentration distribution within the p-type GaAs epitaxial layer 3 appropriate.
Be, etc., has a large diffusion coefficient in GaAs crystals, and not only is it difficult to obtain an appropriate distribution, but the carrier concentration is
It was extremely difficult to achieve a high concentration of IO"cm or higher.
本発明の目的は、前記した従来技術の欠点を解消し、高
いエネルギ変換効率を有するＧａＡｓ系太陽電池を提供
することにある。An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a GaAs solar cell having high energy conversion efficiency.
［課題を解決するための手段］
本発明のＧａＡｓ系太陽電池は、ｎ型ＧａＡｓ基板上に
ｐ型のエピタキシャル層を積層して表裏に電極を形成し
たＧａＡｓ系太陽電池において、上記ｐ型エピタキシャ
ル層を形成するためのｐ型ドーパント元素にカーボンを
用い、そのカーボン濃度がＩ Ｘ １０ ”ｃ ｍ−’
を越える層を上記積層したｐ型エピタキシャル層中に有
するものである。[Means for Solving the Problems] The GaAs solar cell of the present invention is a GaAs solar cell in which a p-type epitaxial layer is laminated on an n-type GaAs substrate and electrodes are formed on the front and back sides. Carbon is used as a p-type dopant element to form
The laminated p-type epitaxial layer has more than 100 layers.
そして、カーボン濃度がＩ Ｘ １×１０１８ｃｍ−’
を越えるキャリア濃度の高い上記ｐ型エピタキシャル層
を安定に作るために、トリメチルガリウムあるいはトリ
エチルガリウム等の有機金属原料を用いた有機金属気相
成長法によって形成することが望ましい。And the carbon concentration is I x 1 x 1018 cm-'
In order to stably produce the above p-type epitaxial layer having a high carrier concentration exceeding , it is desirable to form it by an organometallic vapor phase epitaxy method using an organometallic raw material such as trimethyl gallium or triethyl gallium.
また、カーボン濃度かＩ Ｘ Ｉ Ｏ”ｃ ｍ−’以上
ノ高キャリア濃度ｐ型エピタキシャル層を有し、この高
キャリア濃度ｐ型エピタ牛ンヤル層を表面電極のコンタ
クト層とすることか好ましい。It is also preferable to have a p-type epitaxial layer with a high carrier concentration of carbon concentration IXIO''cm-' or more, and to use this high carrier concentration p-type epitaxial layer as a contact layer of the surface electrode.
さらに、上記高キャリア濃度ｐ型エピタキシャル層のカ
ーボン濃度がＩ Ｘ １×１０１８ｃｒｒ＋”以上で、
かつその厚さが１μｍ以下であることが望ましい。Furthermore, the carbon concentration of the high carrier concentration p-type epitaxial layer is I x 1×10 18 crrr+” or more,
Moreover, it is desirable that the thickness is 1 μm or less.
［作用］
カーボンは拡散係数が小さ（高濃度のドープか可能であ
る。従って、このカーボンをｐ型ドーパント元素に用い
ると、ｐ型エピタキシャル層内のキャリア分布の適正化
が可能となる。[Function] Carbon has a small diffusion coefficient (it can be doped at a high concentration). Therefore, when carbon is used as a p-type dopant element, carrier distribution in the p-type epitaxial layer can be optimized.
また、表面電極コンタクト側のｐ型エビタ牛ンヤル層の
キャリア濃度がｌＸｌ×１０１８ｃｍ′□１以上になる
と、太陽電池に寄生する直列抵抗が減少し、それによっ
て太陽電池の変換効率が大幅に向上する。In addition, when the carrier concentration of the p-type Evita layer on the surface electrode contact side becomes 1Xl×1018cm'□1 or more, the parasitic series resistance of the solar cell decreases, thereby significantly improving the conversion efficiency of the solar cell. .
特に、ｐ型エピタキシャル層の電極コンタクト側のみを
薄く高濃度にドープすることにより、短絡電流密度の低
下をほとんど起こさずに接触抵抗の大幅な改善か図られ
る。In particular, by thinly and highly doping only the electrode contact side of the p-type epitaxial layer, contact resistance can be significantly improved with almost no reduction in short-circuit current density.
［実施例］
本発明の一実施例を説明するための太陽電池構造を第１
図に示す。[Example] A solar cell structure for explaining an example of the present invention is shown in the first example.
As shown in the figure.
太陽電池（セル）は、基板としてＳｉをドープしたｎ型
ＧａＡｓ基板１ （キャリア濃度ｌＸｌ×１０１８ｃｍ
−、厚さ３００μｍ）を用いている。The solar cell (cell) uses an n-type GaAs substrate 1 doped with Si (carrier concentration lXl x 1018 cm) as a substrate.
-, thickness 300 μm).
このｎ型ＧａＡｓ基板１上にｎ型ＧａＡｓエピタキシャ
ル層２． ｐ型ＧａＡｓエピタキシャル１ｉｉ３．高
キャリア濃度ｐ°型ＧａＡｓエピタキシャル層８を順次
エピタキシャル成長して積層する。その高キャリア濃度
ｐ型Ｇ’ａＡｓエピタキシャル層８の上に表面電極５と
窓材であるｐ型ＧａＡＱＡｓエピタキシャル層４を形成
し、さらに反射防止膜６を設けている。また、基板１の
裏面全面に裏面電極７が形成される。On this n-type GaAs substrate 1, an n-type GaAs epitaxial layer 2. p-type GaAs epitaxial 1ii3. High carrier concentration p° type GaAs epitaxial layers 8 are successively epitaxially grown and stacked. A surface electrode 5 and a p-type GaAQAs epitaxial layer 4 as a window material are formed on the high carrier concentration p-type G'aAs epitaxial layer 8, and an antireflection film 6 is further provided. Further, a back electrode 7 is formed on the entire back surface of the substrate 1.
上記ｎ型ＧａＡｓエピタキシャル層２． ｐ型ＧａＡ
ｓエピタキシャル層３．高キャリア濃度ｐ蟹Ｇ ａ Ａ
Ｓ Ｚ ヒ９ ＋ ’ｉ ヤル層８は、ＭＯＶＰＥ法
（有機金属を用いた気相成長法）によって連続的に作成
される。The n-type GaAs epitaxial layer 2. p-type GaA
s epitaxial layer 3. High carrier concentration p crab G a A
The SZhi9+'i layer 8 is continuously created by the MOVPE method (vapor phase epitaxy using organic metals).
また、窓材としてのｐ型ＧａＡＬＡｓエピタキシャル層
４もＭＯＶＰＥ法により作成し、反射防止膜６はプラズ
マＣＶＤ装置によりＳｉ、Ｎ４を堆積して形成される。Further, the p-type GaALAs epitaxial layer 4 as a window material is also formed by the MOVPE method, and the antireflection film 6 is formed by depositing Si and N4 using a plasma CVD apparatus.
表面電極５は窓材のＧａＡ（ｊＡｓエピタキシャル層４
を部分的にエツチングし、高キャリア濃度ｐ型ＧａＡｓ
エピタキシャル層８、あるいはｐ型ＧａＡｓエピタキシ
ャル層３に電極材料が直接接触するように形成しである
。The surface electrode 5 is made of a window material GaA (jAs epitaxial layer 4
is partially etched to form high carrier concentration p-type GaAs.
The electrode material is formed in direct contact with the epitaxial layer 8 or the p-type GaAs epitaxial layer 3.
上記したＭＯＶＰＥ法では原料としてＴＭＧ（トリメチ
ルガリウム）を用いた。特にｐ型エピタキシャル層であ
るｎ型ＧａＡｓエピタキシャル層３゜高キャリア′ａ度
ｐ型ＧａＡｓエピタキシャル層８゜ｐ型ＧａＡｌ２Ａｓ
エピタキシャル層４に導入するカーボン濃度はキナリア
ガス中のＴＭＧの分圧■族／ｍ族比、基板温度を調節す
ることにより現在Ｉ Ｘ １×１０１８ｃｍ−’以下が
ら１．５Ｘ１×１０１８ｃｍ３程度の高濃度まで任意に
制御できるようになっている。この場合、カーボンは原
料のＴＭＧがら供給されていると考えられるが、はとん
どＡ ｓサイトを置換し、アクセプタとしてほぼ１００
％活性化していることに注目すべきである。これを利用
して本実施例では高キャリア濃度ｐ型ＧａＡｓエピタキ
シャル層８のカーボン濃度をＩＸＩＯｃｍ−’以上にし
である。In the MOVPE method described above, TMG (trimethyl gallium) was used as a raw material. In particular, an n-type GaAs epitaxial layer, which is a p-type epitaxial layer, has a 3° high carrier'a degree, a p-type GaAs epitaxial layer, which is a p-type epitaxial layer, and an 8° p-type GaAl2As
The carbon concentration introduced into the epitaxial layer 4 can be adjusted from the current I x 1 x 1018 cm-' to a high concentration of about 1.5 x 1 x 1018 cm3 by adjusting the partial pressure of TMG in the quinaria gas, the group II/m group ratio, and the substrate temperature. It can be controlled arbitrarily. In this case, carbon is thought to be supplied from the raw material TMG, but carbon mostly replaces the As site and serves as an acceptor at approximately 100%
It should be noted that % activation. Taking advantage of this, in this embodiment, the carbon concentration of the high carrier concentration p-type GaAs epitaxial layer 8 is set to be higher than IXIOcm-'.
このよう制御、置換はカーボン元素によりはじめて可能
となるのであって、現在使われているＺｎやＢｅ等の不
純物元素では不可能であり、これらでキャリア濃度Ｉ
Ｘ Ｉ Ｏ”ｃｍ”以上を安定的に作った報告はない。Such control and substitution is only possible with carbon elements, and is not possible with currently used impurity elements such as Zn and Be.
There is no report on stable production of X I O "cm" or more.
次に、セル作成の詳細について述べる。Next, details of cell creation will be described.
ｎ型ＧａＡｓ基板１ （キャリア濃度ｌＸｌ０目ｃｍ−
１厚さ３００μｍ）上に作成したｎ型ＧａＡｓエピタキ
シャル層２は、原料ガスにジシラン（Ｓ＋ｙＨｓ）を添
加して作成したＳ１ドープ結晶でキャリア濃度は２Ｘ
Ｉ Ｏ”ｃｍ−、厚さ６μｍである。第１図のｐ型Ｇａ
、Ａｓエビタ牛ンヤル層３、高キャリア濃度ｐ型ＧａＡ
ｓエピタキシャル層８は、上記ＭＯＶＰＥ法によって連
続的に作成し、それぞれキャリア７Ｊ１度８Ｘ］Ｏ”ｃ
ｍ“、厚さ２μｍと、同じ＜ Ｉ Ｘ ］ Ｏ”ｃｍ
、厚さ００２μｍである。N-type GaAs substrate 1 (carrier concentration lXl0cm-
The n-type GaAs epitaxial layer 2 created on the substrate (1 thickness: 300 μm) is an S1-doped crystal created by adding disilane (S+yHs) to the source gas, and the carrier concentration is 2X.
I O"cm-, thickness 6 μm. The p-type Ga shown in FIG.
, As Evita Gyunyaru layer 3, high carrier concentration p-type GaA
The s epitaxial layer 8 is continuously created by the above MOVPE method, and each carrier 7J1 degree 8X]O"c
m", thickness 2 μm, same < I x ] O" cm
, the thickness is 002 μm.
また、窓材としてのｌ）！１２ＧａＡＱＡｓエピタ牛／
ヤル層４も原料にトリメチルアルミニウム（ＴＭＡ）を
用いたＭＯＶＰＥ法により作成し、そのＡＣｉｉｔ品比
は０．７．キャリア濃度はＩＸＩＯｃｍ−、厚さ０１μ
ｍである。反射防止膜６はプラズマＣＶＤ装置により５
ｉ２Ｎ、を約０．１μｍ堆積した。表面電極５はホトリ
ソグラフィを使って、窓材のＧａＡ（ｊＡｓエピタキシ
ャル層８を部分的にエツチングし、高キャリア濃度ｐ型
ＧａＡｓエピタキシャル層８、あるいはｐ型ＧａＡｓエ
ピタキシャル層３に電極材料が直接接触するように形成
した。また、裏面電極７は基板ｌの裏面全面に形成した
。Also l) as a window material! 12GaAQAs Epita cow/
The coating layer 4 was also created by the MOVPE method using trimethylaluminum (TMA) as a raw material, and its ACiit product ratio was 0.7. Carrier concentration is IXIOcm-, thickness 01μ
It is m. The anti-reflection film 6 is formed using a plasma CVD device.
About 0.1 μm of i2N was deposited. The surface electrode 5 is formed by partially etching the window material GaA(jAs epitaxial layer 8) using photolithography, so that the electrode material directly contacts the high carrier concentration p-type GaAs epitaxial layer 8 or the p-type GaAs epitaxial layer 3. Further, the back electrode 7 was formed on the entire back surface of the substrate l.
さて、本実施例の太陽電池の効果を確認するため、第１
図の構造において高キャリア濃ｆｔｐ型ＧａＡｓエピタ
キシャル層８の有無のみが異なる二種類の太陽電池を上
記ＭＯＶＰＥ法で作成し、そのエネルギー変換効率をＡ
Ｍ １ （Ａｉｒ Ｍａｓｓ １の略で、地上で太陽が
天頂にある場合の太陽光を示す。Now, in order to confirm the effect of the solar cell of this example, the first
Two types of solar cells with the structure shown in the figure differing only in the presence or absence of the high carrier-concentrated ftp type GaAs epitaxial layer 8 were fabricated using the above MOVPE method, and the energy conversion efficiency was A
M1 (abbreviation for Air Mass 1) indicates sunlight when the sun is at the zenith on the ground.
）疑似スペクトル条件で調べた。その結果は、次に述べ
るように本実施例の有効性を十分証明し得るものであっ
た。) investigated under pseudospectral conditions. The results were sufficient to prove the effectiveness of this example, as described below.
高キャリア濃度ｐ型ＧａＡｓエピタキシャル層８を有す
る太陽電池の直列抵抗は低く、変換効率も高キャリア濃
度ｐ型ＧａＡｓエピタキシャル層８を有さないものが１
７３％であったのに対し、上記エビタ牛／ヤル層８を有
するものが２２８％となり大巾な改善が認められた。The series resistance of the solar cell having the high carrier concentration p-type GaAs epitaxial layer 8 is low, and the conversion efficiency of the solar cell having no high carrier concentration p-type GaAs epitaxial layer 8 is 1.
The percentage was 73%, whereas the percentage for those with Evita beef/Yaru layer 8 was 228%, indicating a significant improvement.
以上述べたように本実施例は、ｐ型エピタキシャル層形
成のためのドーパントとして従来使っていたＺｎ、Ｂｅ
等に代えてＣ（カーボン）を用いたものである。従って
、ＧａＡｓ結晶中のでの拡散係数が小さく、適正な分布
が得られ、牛＋ ’）ア濃度も５Ｘ１×１０１８ｃｍ−
’以上の高ｉ＃度にすることが可能となる。その結果、
表面電極への直列抵抗が小さくなって変換効率が向上す
る。As described above, this example uses Zn and Be, which have been conventionally used as dopants for forming a p-type epitaxial layer.
etc., using C (carbon) instead. Therefore, the diffusion coefficient in the GaAs crystal is small, a proper distribution is obtained, and the a concentration is 5X1x1018cm-
'It is possible to achieve a high i# degree of more than '. the result,
The series resistance to the surface electrode is reduced and the conversion efficiency is improved.
なお、上記実施例では、カーボン濃度が１×１０ ”ｃ
ｍ ”を越える層としてｐ型ＧａＡρＡｓエピタキ／
ヤル層と、表面電極直下の高キャリア濃度ｐ型ＧａＡｓ
エピタ牛シャル層とし、このうち特に後者のＧａＡｓエ
ビタ牛／ヤル層を１×１×１０１８ｃｍ′□３以上とし
たが、本発明はこれに限定されるものではない。例えば
、高キャリアａ度ｐ型エビタキ／＋ル層を設けずに、ｐ
型ＧａＡｓ層または／およびｐ型ＧａＡ（Ａｓエピタキ
シ＋ル層をＩ ｘ １×１０１８ｃｍ−’のカーボン濃
度としたり、あるいは高キャリア濃度ｐ型エピタキシャ
ル層を設けるが、窓材であるｐ型ＧａＡζＡｓエピタキ
シャル層側に設けるようにしてもよい。In the above example, the carbon concentration was 1×10”c
p-type GaAρAs epitaxy/
layer and high carrier concentration p-type GaAs directly under the surface electrode.
The epitaxial layer was made to have a thickness of 1×1×10 18 cm'□3 or more, especially the latter GaAs epitaxial layer, but the present invention is not limited thereto. For example, without providing a high carrier a degree p type shrimp layer/+
type GaAs layer or/and p-type GaA (As epitaxial layer) with a carbon concentration of I x 1 x 1018 cm-' or a high carrier concentration p-type epitaxial layer, but the p-type GaAζAs epitaxial layer which is the window material It may also be provided on the side.
［発明の２／ｌ果］ 本発明によれば次のような効果を発揮する。[2/1 result of invention] According to the present invention, the following effects are achieved.
（１）Ｉ求項】のＧａＡｓ系太陽電池においては、ｐ型
ドーパント元素として、拡散係数が小さく、高濃度にド
ープすることができるカーボンを用いたことにより、ｐ
型エピタキシャル層内のキャリア濃度分布の最適化が容
易に行える。In the GaAs solar cell of (1) I, carbon is used as the p-type dopant element, and carbon has a small diffusion coefficient and can be doped at a high concentration.
The carrier concentration distribution within the type epitaxial layer can be easily optimized.
（２）請求項２のＧａＡｓ系太陽電池においては、ｐ型
エピタキシャル層を低濃度から高濃度まで任意に制御で
きる有機金属原料を用いた有機金属気相成長法によって
形成されるので、高濃度のキャリアを安定的に作ること
ができる。(2) In the GaAs-based solar cell of claim 2, the p-type epitaxial layer is formed by an organometallic vapor phase epitaxy method using an organometallic raw material that can be arbitrarily controlled from a low concentration to a high concentration. You can create a stable career.
（３）請求項３のＧａＡｓ系太陽電池においては、表面
電極のコンタクト層を高キャリア濃妾ｐ梨エピタキシャ
ル層で形成したので、接触抵抗を小さくできる。(3) In the GaAs solar cell of the third aspect, since the contact layer of the surface electrode is formed of a high carrier concentration epitaxial layer, the contact resistance can be reduced.
（４）請求項４のＧａＡｓ系太陽電池においては、ｐ型
エピタキ／ヤル層の電極接触側のみを薄（高濃度にドー
プすることにより、短絡電流密度の低下をほとんど起こ
さずに接触抵抗の大幅な改善が図られる。そのため、太
陽電池としての直列抵抗が減りエネルギー変換効率を大
幅に改善できる。(4) In the GaAs solar cell of claim 4, only the electrode contact side of the p-type epitaxial layer is thinly (highly doped), thereby significantly increasing the contact resistance without causing almost any decrease in short-circuit current density. As a result, the series resistance of the solar cell can be reduced and the energy conversion efficiency can be significantly improved.
第１図は本発明の高キャリア濃度ｐ型ＧａＡｓエピタキ
シャル層ををするＧａＡｓ系太陽電池の一実施例の構造
を示す断面図、第２図は従来の代表的なＧａＡｓ太陽電
池の構造を示す断面図である。
１はｎ型ＧａＡｓ基板、２はｎ型ＧａＡｓエビタキノヤ
ル層、３はｐ型ＧａＡｓエビタキ／セル層、４はｐ型Ｇ
ａＡｓｘビタキ／ヤル（窓層）、５１表面電極、６は反
ｉ＋ｔろ重膜、７は表面電極、８ハＡ ＋ヤリアａ度ｐ
型Ｇ ａ Ａ ｓエピタキシャル層である。Fig. 1 is a cross-sectional view showing the structure of an embodiment of a GaAs solar cell having a high carrier concentration p-type GaAs epitaxial layer according to the present invention, and Fig. 2 is a cross-sectional view showing the structure of a typical conventional GaAs solar cell. It is a diagram. 1 is an n-type GaAs substrate, 2 is an n-type GaAs layer, 3 is a p-type GaAs layer/cell layer, and 4 is a p-type G layer.
aAsx Vitaki/Yaru (window layer), 51 surface electrode, 6 is anti-i+t filter membrane, 7 is surface electrode, 8ha A + Yaria a degree p
It is a type GaAs epitaxial layer.
Claims (4)
積層して表裏に電極を形成したＧａＡｓ系太陽電池にお
いて、 上記ｐ型エピタキシャル層を形成するためのｐ型ドーパ
ント元素にカーボンを用い、 そのカーボン濃度が１×１０＾１＾８ｃｍ＾−＾３を越
える層を上記積層したｐ型エピタキシャル層中に有する
ことを特徴とするＧａＡｓ系太陽電池。(1) In a GaAs solar cell in which a p-type epitaxial layer is laminated on an n-type GaAs substrate and electrodes are formed on the front and back sides, carbon is used as a p-type dopant element for forming the p-type epitaxial layer, and A GaAs solar cell characterized in that the laminated p-type epitaxial layer has a layer having a carbon concentration exceeding 1×10^1^8 cm^-^3.
越える上記ｐ型エピタキシャル層がトリメチルガリウム
あるいはトリエチルガリウム等の有機金属原料を用いた
有機金属気相成長法によって形成されることを特徴とす
る請求項１に記載のＧａＡｓ系太陽電池。(2) The above p-type epitaxial layer with a carbon concentration exceeding 1 x 10^1^8 cm^-^3 is formed by organometallic vapor phase epitaxy using an organometallic raw material such as trimethyl gallium or triethyl gallium. The GaAs solar cell according to claim 1.
上の高キャリア濃度ｐ型エピタキシャル層を有し、この
高キャリア濃度ｐ型エピタキシャル層を表面電極のコン
タクト層としたことを特徴とする請求項１または２に記
載のＧａＡｓ系太陽電池。(3) It has a high carrier concentration p-type epitaxial layer with a carbon concentration of 1×10^1^8 cm^-^3 or more, and this high carrier concentration p-type epitaxial layer is used as the contact layer of the surface electrode. The GaAs solar cell according to claim 1 or 2.
が１μｍ以下であることを特徴とする請求項３に記載の
ＧａＡｓ系太陽電池。(4) The GaAs solar cell according to claim 3, wherein the high carrier concentration p-type epitaxial layer has a thickness of 1 μm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2087797A JP2722761B2 (en) | 1990-04-02 | 1990-04-02 | GaAs solar cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2087797A JP2722761B2 (en) | 1990-04-02 | 1990-04-02 | GaAs solar cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03285368A true JPH03285368A (en) | 1991-12-16 |
| JP2722761B2 JP2722761B2 (en) | 1998-03-09 |
Family
ID=13924972
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2087797A Expired - Fee Related JP2722761B2 (en) | 1990-04-02 | 1990-04-02 | GaAs solar cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2722761B2 (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009111667A2 (en) * | 2008-03-05 | 2009-09-11 | Varian Semiconductor Equipment Associates | Establishing a high phosphorus concentration in solar cells |
| WO2010126665A2 (en) * | 2009-04-30 | 2010-11-04 | Abound Solar, Inc. | Doping of semiconductor layer for improved efficiency of semiconductor structures |
| JP2012099807A (en) * | 2010-11-03 | 2012-05-24 | Alta Devices Inc | Optoelectronic device having heterojunction |
| US9502594B2 (en) | 2012-01-19 | 2016-11-22 | Alta Devices, Inc. | Thin-film semiconductor optoelectronic device with textured front and/or back surface prepared from template layer and etching |
| US9691921B2 (en) | 2009-10-14 | 2017-06-27 | Alta Devices, Inc. | Textured metallic back reflector |
| US9768329B1 (en) | 2009-10-23 | 2017-09-19 | Alta Devices, Inc. | Multi-junction optoelectronic device |
| US10326033B2 (en) | 2008-10-23 | 2019-06-18 | Alta Devices, Inc. | Photovoltaic device |
| US10615304B2 (en) | 2010-10-13 | 2020-04-07 | Alta Devices, Inc. | Optoelectronic device with dielectric layer and method of manufacture |
| US11038080B2 (en) | 2012-01-19 | 2021-06-15 | Utica Leaseco, Llc | Thin-film semiconductor optoelectronic device with textured front and/or back surface prepared from etching |
| US11271133B2 (en) | 2009-10-23 | 2022-03-08 | Utica Leaseco, Llc | Multi-junction optoelectronic device with group IV semiconductor as a bottom junction |
| US11271128B2 (en) | 2009-10-23 | 2022-03-08 | Utica Leaseco, Llc | Multi-junction optoelectronic device |
Citations (1)
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|---|---|---|---|---|
| JPS5846617A (en) * | 1981-09-14 | 1983-03-18 | Nec Corp | Formation of compound semiconductor p-n junction |
-
1990
- 1990-04-02 JP JP2087797A patent/JP2722761B2/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5846617A (en) * | 1981-09-14 | 1983-03-18 | Nec Corp | Formation of compound semiconductor p-n junction |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009111667A2 (en) * | 2008-03-05 | 2009-09-11 | Varian Semiconductor Equipment Associates | Establishing a high phosphorus concentration in solar cells |
| WO2009111667A3 (en) * | 2008-03-05 | 2009-12-10 | Varian Semiconductor Equipment Associates | Establishing a high phosporus concentration in solar cells |
| US10505058B2 (en) | 2008-10-23 | 2019-12-10 | Alta Devices, Inc. | Photovoltaic device |
| US9136418B2 (en) | 2008-10-23 | 2015-09-15 | Alta Devices, Inc. | Optoelectronic devices including heterojunction and intermediate layer |
| US9178099B2 (en) | 2008-10-23 | 2015-11-03 | Alta Devices, Inc. | Methods for forming optoelectronic devices including heterojunction |
| US10326033B2 (en) | 2008-10-23 | 2019-06-18 | Alta Devices, Inc. | Photovoltaic device |
| WO2010126665A2 (en) * | 2009-04-30 | 2010-11-04 | Abound Solar, Inc. | Doping of semiconductor layer for improved efficiency of semiconductor structures |
| WO2010126665A3 (en) * | 2009-04-30 | 2011-01-13 | Abound Solar, Inc. | Doping of semiconductor layer for improved efficiency of semiconductor structures |
| US9691921B2 (en) | 2009-10-14 | 2017-06-27 | Alta Devices, Inc. | Textured metallic back reflector |
| US9768329B1 (en) | 2009-10-23 | 2017-09-19 | Alta Devices, Inc. | Multi-junction optoelectronic device |
| US11271133B2 (en) | 2009-10-23 | 2022-03-08 | Utica Leaseco, Llc | Multi-junction optoelectronic device with group IV semiconductor as a bottom junction |
| US11271128B2 (en) | 2009-10-23 | 2022-03-08 | Utica Leaseco, Llc | Multi-junction optoelectronic device |
| US10615304B2 (en) | 2010-10-13 | 2020-04-07 | Alta Devices, Inc. | Optoelectronic device with dielectric layer and method of manufacture |
| JP2012099807A (en) * | 2010-11-03 | 2012-05-24 | Alta Devices Inc | Optoelectronic device having heterojunction |
| US10008628B2 (en) | 2012-01-19 | 2018-06-26 | Alta Devices, Inc. | Thin-film semiconductor optoelectronic device with textured front and/or back surface prepared from template layer and etching |
| US9502594B2 (en) | 2012-01-19 | 2016-11-22 | Alta Devices, Inc. | Thin-film semiconductor optoelectronic device with textured front and/or back surface prepared from template layer and etching |
| US11038080B2 (en) | 2012-01-19 | 2021-06-15 | Utica Leaseco, Llc | Thin-film semiconductor optoelectronic device with textured front and/or back surface prepared from etching |
| US11942566B2 (en) | 2012-01-19 | 2024-03-26 | Utica Leaseco, Llc | Thin-film semiconductor optoelectronic device with textured front and/or back surface prepared from etching |
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| Publication number | Publication date |
|---|---|
| JP2722761B2 (en) | 1998-03-09 |
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