JPH0340515B2 - - Google Patents
Info
- Publication number
- JPH0340515B2 JPH0340515B2 JP56066689A JP6668981A JPH0340515B2 JP H0340515 B2 JPH0340515 B2 JP H0340515B2 JP 56066689 A JP56066689 A JP 56066689A JP 6668981 A JP6668981 A JP 6668981A JP H0340515 B2 JPH0340515 B2 JP H0340515B2
- Authority
- JP
- Japan
- Prior art keywords
- type
- layer
- light
- amorphous silicon
- amorphous semiconductor
- 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.)
- Expired - Lifetime
Links
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 45
- 239000004065 semiconductor Substances 0.000 claims description 37
- 230000003287 optical effect Effects 0.000 claims description 11
- 238000009792 diffusion process Methods 0.000 claims description 10
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 4
- 238000000354 decomposition reaction Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical group [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 7
- 229910052739 hydrogen Inorganic materials 0.000 description 7
- 239000001257 hydrogen Substances 0.000 description 7
- 229910000077 silane Inorganic materials 0.000 description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 229910010271 silicon carbide Inorganic materials 0.000 description 5
- 239000000758 substrate Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000031700 light absorption Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910006404 SnO 2 Inorganic materials 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 150000002222 fluorine compounds Chemical class 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 150000004756 silanes Chemical class 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- XYFCBTPGUUZFHI-UHFFFAOYSA-N Phosphine Chemical compound P XYFCBTPGUUZFHI-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- 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 at least one potential-jump barrier or surface barrier
- H01L31/075—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 at least one potential-jump barrier or surface barrier the potential barriers being only of the PIN type
-
- 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
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/20—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials
-
- 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
- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/20—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials
- H01L31/202—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials including only elements of Group IV of the Periodic System
- H01L31/204—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials including only elements of Group IV of the Periodic System including AIVBIV alloys, e.g. SiGe, SiC
-
- 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
- Y02E10/548—Amorphous silicon PV 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Description
本発明は、アモルフアス半導体／アモルフアス
シリコンヘテロ接合光電素子に関する。
シラン（SiH4）のプラズマ分解法で得られる
アモルフアスシリコンは、W.E.Spear等によつ
て、PH3やB2H6でドープする事により、その伝
導度を大きく変える事が出来ることが発見され
（1976年）、D.E.Carlson等によつてアモルフアス
シリコンを用いた太陽電池が試作（1976年）され
て以来注目を集め、アモルフアスシリコン薄膜太
陽電池の効率を改善する研究が活発に行われてい
る。
これまでの研究により、アモルフアスシリコン
薄膜光電素子の構造としてはシヨツトキーバリヤ
ー型、pin型、MIS型、ヘテロ接合型があり、そ
のうち前三者が高効率太陽電池として有望視され
ている。すなわちシヨツトキーバリヤー型で5.5
％（D.E.カールソン他、1977年）、MIS型で4.8％
（J.I.B.ウイルソン他、1978年）、pin型で4.5％
（浜川桂弘1978年）の変換効率が達成されている。
pinジヤンクシヨン型太陽電池の場合、ｐ型又
はｎ型アモルフアスシリコンではキヤリヤーの寿
命が短かく、有効なキヤリヤーにならず、また光
の吸収係数がｉ層に比べて大きい事からｐ層での
光の吸収ロスが大きい点に問題があつた。
このような欠点を改良する為にインバーテイド
pin型の光電素子が提案されている。すなわちｎ
型アモルフアスシリコン側から光を照射する素子
である。この素子はｐ型に比べると光の吸収係数
が比較的小さい為にやや有利と考えられる。しか
しこのｎ型アモルフアスシリコンでも光の吸収ロ
スがある点ではｐ型と変りない。
更にこのｐ層又はｎ層における光の吸収ロスを
少なくする方法として、ｐ層又はｎ層にアモルフ
アスシリコンよりも光学的エネルギーバンドギヤ
ツプEgの大なる半導体を用いるという考え方が
ある。半導体はその光学的エネルギーバンドギヤ
ツプEgよりも大きいエネルギーを有する光のみ
を吸収するので、Eg大なる半導体は光入射側の
ｐ層又はｎ層材料（窓材料）として有用である。
そして米国特許第4109271号には、Eg≒2.2〜
3.2eVのａ−SiCをｐ層又はｎ層に用いるPin接合
素子が示されている。しかし、ここで用いられて
いるａ−SiCは電導度（σ）が極めて低いため、
ｐ層又はｎ層がａ−Siである場合よりも低いもの
となつている。
これに対し、本発明者らは、ａ−SiCが製造条
件により価電子制御可能であることを発見し、こ
の価電子制御を適切に行うことによつて、その電
気伝導度を10-8（Ω・cm）-1以上に成し得ることを
確認すると共に、電気伝導度を10-8（Ω・cm）-1以
上にしたａ−SiCをpin接合光電素子のｐ層又は
ｎ層の少なくとも一方に用いることにより高効率
の光起電力素子が得られることを見出し、先の出
願において開示した（特開昭57−126175号公報参
照）。
本発明者らは、更に、高効率、高電圧のpin型
光電素子を得る為に鋭意研究した結果、光学的バ
ンドギヤツプが約1.85eV以上でありかつ20℃に
おける電気伝導度が約10-8（Ω・cm）-1以上であ
り、かつｐ−ｉ−ｎ接合した場合の拡散電位Vd
が約1.1volts以上であるｐ型又はｎ型アモルフア
スシリコンを主体とするアモルフアスシリコンカ
ーバイドのドープ薄膜を、pin接合素子のｐ又は
ｎ層の少なくとも一方に用いることにより短絡電
流と開放電圧を大幅に改善できることを見い出し
たもので、太陽電池や光スイツチ等の光起電力素
子として用いることができる。以下にその詳細を
説明する。
本発明のアモルフアスシリコンは、シラン
（SiH4）又はその誘導体又はフツ化シラン又はそ
の誘導体、又はこれらの混合物と、水素又は水素
で希釈したアルゴン、ヘリウム等の不活性ガスと
の混合ガスを、容量結合法又は誘導結合法による
高周波グロー分解又は直流グロー放電分解するこ
とにより得られる。混合ガス中のシランの濃度
は、通常0.5〜50％、好ましくは１〜20％である。
基板の温度は200〜300℃が好ましく、透明電極
（ITO、SnO2等）を蒸着したガラスや高分子フイ
ルム、金属等、太陽電池の構成に必要なあらゆる
基板が含まれる。
太陽電池の基本構成は、第１図のａ，ｂに代表
例が示される。ａはｐ側から光を照射するタイプ
で、例えばガラス−透明電極−ｐ−ｉ−ｎ−Al
の構成、ｂはｎ側から光を照射するタイプで、例
えばステンレス−ｐ−ｉ−ｎ−透明電極の構成で
ある。その他、ｐ層と透明電極の間に薄い絶縁層
をつけたり、薄い金属層をつけた構造でもよい。
要はｐ−ｉ−ｎ接合を基本とするものであればい
かなる構成でもよい。
シラン若しくはその誘導体、又はフツ化シラン
若しくはその誘導体、又はこれらの混合物のグロ
ー放電分解で得られる約10-7秒以上のキヤリヤー
寿命で約1017cm-3V-1以下の局在準位密度および
10-3cm2／Ｖ以上の易動度をもつ真性アモルフアス
シリコン（以下、ｉ型ａ−Siという）をｉ層とし
て、ｐ型とｎ型ドープ半導体で接合したpin接合
構造にするわけであるが、本発明ではｐ層又はｎ
層の少なくとも一方、すなわち少なくとも光を照
射する側に、光学的バンドギヤツプが約1.85eV
以上でありかつ20℃における電気伝導度が約10-8
（Ω・cm）-1以上であり、かつｐ−ｉ−ｎ接合した
場合の拡散電位Vdが約1.1volts以上であるｐ型又
はｎ型アモルフアス半導体を用いることを特徴と
する。ｐ層とｎ層の両方に用いてもよい。又本発
明のアモルフアス半導体を用いないドープ層は、
上記ｉ型ａ−Siをｐ型で用いる場合は周期率表
族の元素でドープし、ｎ型で用いる場合は周期率
表Ｖ族の元素でドープすればよい。
本発明のアモルフアス半導体は、一般式ａ−
Si(1-X)Cx等で例示されるアモルフアスシリコンカ
ーバイト等である。これらはシリコンの水素又は
フツ素化合物と炭素の水素又はフツ素化合物をグ
ロー放電分解して得られる。その詳細は、本出願
人が先に出願した特許出願、すなわちａ−Si(1-X)
Cxについて特願昭56−012313号に記載している。
要は光学的バンドギヤツプが約1.85eV以上であ
りかつ20℃における電気伝導度が約10-8（Ω・cm）
-1以上であり、かつｐ−ｉ−ｎ接合した場合の拡
散電位Vdが約1.1volts以上であるｐ型又はｎ型ア
モルフアス半導体を満すものであればいかなるも
のであつてもよい。
これらのアモルフアス半導体は光学的バンドギ
ヤツプが大きく、そのために、ｐ−ｉ−ｎ接合光
起電力素子の窓材料として用いると短絡電流Jsc
の増加は当然考えられるが、いずれの場合も非常
に大きな開放電圧Vocを示す。本発明の光起電力
素子において第２図に示すバンドプロフアイルの
拡散電位Vdとその素子の開放電圧に相関のある
事を見い出した。本発明の場合Vdは約1.1volt以
上であるが、この関係は光照射する側のアモルフ
アス半導体の種類に関係なくほぼ同一の傾向を示
している。この拡散電位は光照射する側のアモル
フアス半導体の光学的バンドギヤツプEg・outか
らｐ、ｎドープ層のフエルミレベルEfの差を差
し引くことによつて得られる。すなわち第２図に
示すように、ｎ側の伝導帯のエネルギーレベルを
Ecn、ｐ側の価電子帯のエネルギーレベルをEvp
として、電気伝導度の温度依存性から活性化エネ
ルギーΔEpとΔEnが求められる。ｐ型の場合ΔEp
＝Ef−Evp、ｎ型の場合ΔEn＝Ecn−EfでeVd＝
Eg・opt−（ΔEp＋ΔEn）である。ｎ側から光照
射する場合も同様にｎ型アモルフアス半導体の光
学的バンドギヤツプEg・optからｐ、ｎのフエル
ミレベルEfの差を差し引いて求められる。
本発明の場合Eg・outが約1.85eV以上でかつ
Vdが約1.1volts以上である。このような条件を満
たすアモルフアス半導体を用いたヘテロ接合光起
電力素子はVscとVocが著しく改善される。
本発明ではさらに室温での電気伝導度が10-8
（Ω・cm）-1以上としているが、これ以下であると
フイルフアクターFFが小さくなり変換効率が実
用的でなくなるからである。
本発明のヘテロ接合光電素子について以下に具
体的に説明すると、次の通りである。代表的な構
造は透明電極／ｐ型アモルフアス半導体／ｉ型ａ
−Si／ｎ型ａ−Si／電極の構造で、透明電極側か
ら光を照射する。透明電極はITOやSnO2特に
SnO2が好ましく、ガラス基板にあらかじめ蒸着
して用いたりｐ型アモルフアス半導体上に直接蒸
着してもよい。光を照射する側のｐ型アモルフア
ス半導体層の厚みは約30Åから300Å好ましくは
50Åから200Å、ｉ型−Si層の厚みは本発明の場
合限定されないが約2500〜10000Åが用いられる。
ｎ型ａ−Si層はオーミツクコンタクトをとるため
の層で厚みは限定されないが約150Å〜600Åが用
いられる。又このｎ型ａ−Siの代わりに本発明の
ｎ型アモルフアス半導体を用いてもよい。
もう１つの代表的な構造は透明電極／ｎ型アモ
ルフアス半導体／ｉ型ａ−Si／ｐ型ａ−Si／電極
の構造で、透明電極側から光を照射する。光を照
射する側のｎ型アモルフアス半導体の厚みは約30
Åから300Å好ましくは50Å〜200Å、ｉ型ａ−Si
層の厚みは限定されないが約2500〜10000Åが通
常用いられる。ｐ型ａ−Si層の厚みは限定されな
いが約150Å〜600Åが用いられる。又このｐ型ａ
−Siの代わりに本発発明のｐ型アモルフアス半導
体を用いても良い。透明電極の素材及び蒸着法に
ついては同様である。
次に実施例により本発明の効果について説明す
る。内径11cmの石英反応管を用い14.56MHzの高
周波でグロー放電分解を行う。ｉ型ａ−Siは、水
素で希釈したシランを２〜10Torrでグロー放電
分解して得られる。ｎ型ａ−Siは水素で希釈した
シランとフオスフイン（pH3）（pH3／SiH4＝0.5
モル％）を同様にグロー放電分解して得られる。
ｐ型ａ−Si(1-X)Cxは水素で希釈したシラン、メタ
ン（CH4）、ジボラン（Ｂ／（Si＋Ｃ）＝0.1atom
％）を同様にグロー放電分解して得られる。ここ
でａ−Si(1-X)Cxは、グロー放電時のガス組成を変
量してそのアトミツクフラクシヨンｘが0.75〜
0.05になるようにした。
太陽電池の構成は、25Ω／□のSnO2薄膜のつ
いたガラス基板のSnO2面に、ｐ型ａ−Si(1-X)Cx、
ｉ型ａ−Si、ｎ型ａ−Siの順に堆積し、最後に
3.3mm2のアルミニウムを蒸着してAM−１（100ｍ
Ｗ／cm2）のソーラーシミレータで太陽電池特性を
調べた。グロー放電時の基板温度は250℃で行つ
た。又、ｉ層は5000Å、ｎ層は500Å、ｐ型ａ−
Si(1-X)Cxの厚みは135Åである。
ｐ型ａ−Si(1-X)Cxの膜組成による太陽電池特性
を表に示すと、次のようである。
The present invention relates to an amorphous semiconductor/amorphous silicon heterojunction photoelectric device. It was discovered by WESpear et al. that the conductivity of amorphous silicon obtained by plasma decomposition of silane (SiH 4 ) could be greatly changed by doping it with PH 3 or B 2 H 6 ( Since solar cells using amorphous silicon were prototyped by DE Carlson et al. (1976), they have attracted attention, and research has been actively conducted to improve the efficiency of amorphous silicon thin-film solar cells. Research has shown that amorphous silicon thin-film photovoltaic devices can be structured as Schottky barrier type, pin type, MIS type, and heterojunction type, of which the first three are considered to be promising as high-efficiency solar cells. i.e. 5.5 for shot key barrier type.
% (DE Carlson et al., 1977), 4.8% for MIS type
(JIB Wilson et al., 1978), 4.5% for pin type
(Katsuhiro Hamakawa 1978) conversion efficiency has been achieved. In the case of pin junction type solar cells, p-type or n-type amorphous silicon has a short carrier life and is not an effective carrier, and the light absorption coefficient is larger than that of the i-layer, so light in the p-layer is The problem was that the absorption loss was large. Inverted to improve these shortcomings
A pin-type photoelectric element has been proposed. i.e. n
This is an element that irradiates light from the amorphous silicon side. This element is considered to be somewhat advantageous because it has a relatively small light absorption coefficient compared to the p-type element. However, this n-type amorphous silicon is no different from the p-type in that there is light absorption loss. Furthermore, as a method of reducing light absorption loss in the p-layer or n-layer, there is a concept of using a semiconductor with a larger optical energy band gap Eg than amorphous silicon for the p-layer or n-layer. Since a semiconductor absorbs only light having an energy greater than its optical energy bandgap Eg, a semiconductor with a large Eg is useful as a p-layer or n-layer material (window material) on the light incident side.
And in U.S. Patent No. 4109271, Eg≒2.2~
A pin junction device using 3.2 eV a-SiC in the p layer or n layer is shown. However, since the a-SiC used here has extremely low conductivity (σ),
This is lower than when the p-layer or n-layer is made of a-Si. In contrast, the present inventors discovered that the valence electrons of a-SiC can be controlled by controlling the manufacturing conditions, and by appropriately controlling the valence electrons, the electrical conductivity of a-SiC can be increased to 10 -8 ( In addition to confirming that it is possible to achieve electrical conductivity of 10 -8 (Ω cm) -1 or higher, a-SiC with an electrical conductivity of 10 -8 (Ω cm) -1 or higher can be used at least in the p layer or n layer of a pin junction photoelectric device. It was discovered that a highly efficient photovoltaic device could be obtained by using this method for one purpose, and this was disclosed in a previous application (see Japanese Patent Laid-Open No. 126175/1983). The present inventors further conducted intensive research to obtain a high-efficiency, high-voltage pin-type photoelectric device, and found that the optical band gap was approximately 1.85 eV or more and the electrical conductivity at 20°C was approximately 10 -8 ( Ω・cm) -1 or more, and the diffusion potential Vd when pin junction is formed
By using a doped thin film of amorphous silicon carbide mainly composed of p-type or n-type amorphous silicon with a voltage of about 1.1 volts or more for at least one of the p or n layer of the pin junction element, short-circuit current and open circuit voltage can be significantly reduced. It has been discovered that this can be improved in terms of performance, and can be used as photovoltaic elements such as solar cells and light switches. The details will be explained below. The amorphous silicon of the present invention can be produced using a mixed gas of silane (SiH 4 ) or its derivatives, fluorinated silane or its derivatives, or a mixture thereof, and hydrogen or an inert gas such as argon or helium diluted with hydrogen. It can be obtained by high frequency glow decomposition or direct current glow discharge decomposition using a capacitive coupling method or an inductive coupling method. The concentration of silane in the mixed gas is usually 0.5 to 50%, preferably 1 to 20%. The temperature of the substrate is preferably 200 to 300°C, and includes any substrate necessary for the construction of a solar cell, such as glass on which a transparent electrode (ITO, SnO 2 , etc.) is vapor-deposited, polymer film, metal, etc. Typical examples of the basic configuration of a solar cell are shown in a and b of FIG. A is a type that irradiates light from the p side, for example, glass-transparent electrode-p-i-n-Al
The structure b is a type in which light is irradiated from the n side, for example, a stainless steel pin transparent electrode structure. In addition, a structure in which a thin insulating layer or a thin metal layer is provided between the p-layer and the transparent electrode may be used.
In short, any structure may be used as long as it is based on a pin junction. A localized level density of about 10 17 cm -3 V -1 or less with a carrier lifetime of about 10 -7 seconds or more obtained by glow discharge decomposition of silane or its derivatives, or fluorinated silanes or its derivatives, or mixtures thereof. and
Intrinsic amorphous silicon (hereinafter referred to as i-type a-Si) with a mobility of 10 -3 cm 2 /V or more is used as the i layer, and a pin junction structure is created in which p-type and n-type doped semiconductors are joined. However, in the present invention, p layer or n
At least one of the layers, at least the side that receives the light, has an optical bandgap of approximately 1.85 eV.
or more, and the electrical conductivity at 20℃ is approximately 10 -8
(Ω·cm) −1 or more and a p-type or n-type amorphous semiconductor having a diffusion potential Vd of about 1.1 volts or more when a pin junction is formed. It may be used for both the p layer and the n layer. Further, the doped layer of the present invention that does not use an amorphous semiconductor is
When the i-type a-Si is used as a p-type, it may be doped with an element of group V of the periodic table, and when it is used as an n-type, it may be doped with an element of group V of the periodic table. The amorphous semiconductor of the present invention has the general formula a-
These include amorphous silicon carbide exemplified by Si (1-X) C x and the like. These are obtained by glow discharge decomposition of hydrogen or fluorine compounds of silicon and hydrogen or fluorine compounds of carbon. The details are in the patent application previously filed by the applicant, namely a-Si (1-X).
C x is described in Japanese Patent Application No. 56-012313.
The important thing is that the optical bandgap is approximately 1.85eV or more and the electrical conductivity at 20℃ is approximately 10 -8 (Ω cm).
-1 or more, and any material may be used as long as it satisfies a p-type or n-type amorphous semiconductor having a diffusion potential Vd of about 1.1 volts or more when a pin junction is formed. These amorphous semiconductors have a large optical bandgap, and therefore, when used as a window material for a pin junction photovoltaic device, the short circuit current Jsc
Of course, an increase in Voc is conceivable, but in either case, the open circuit voltage Voc is extremely large. In the photovoltaic device of the present invention, it has been found that there is a correlation between the diffusion potential Vd of the band profile shown in FIG. 2 and the open circuit voltage of the device. In the case of the present invention, Vd is about 1.1 volt or more, and this relationship shows almost the same tendency regardless of the type of amorphous semiconductor on the side of light irradiation. This diffusion potential is obtained by subtracting the difference between the fermi levels Ef of the p- and n-doped layers from the optical bandgap Eg·out of the amorphous semiconductor on the side to which light is irradiated. In other words, as shown in Figure 2, the energy level of the n-side conduction band is
Ecn, the energy level of the p-side valence band is Evp
, the activation energies ΔEp and ΔEn can be found from the temperature dependence of electrical conductivity. For p-type, ΔEp
= Ef - Evp, for n type ΔEn = Ecn - Ef and eVd =
Eg・opt−(ΔEp+ΔEn). When light is irradiated from the n side, it is similarly determined by subtracting the difference between the p and n fermi levels Ef from the optical band gap Eg·opt of the n-type amorphous semiconductor. In the case of the present invention, Eg・out is approximately 1.85eV or more and
Vd is approximately 1.1 volts or more. A heterojunction photovoltaic device using an amorphous semiconductor that satisfies these conditions has significantly improved Vsc and Voc. In the present invention, the electrical conductivity at room temperature is 10 -8
(Ω·cm) -1 or more, but if it is less than this, the film factor FF becomes small and the conversion efficiency becomes impractical. The heterojunction photoelectric device of the present invention will be specifically explained below. Typical structures are transparent electrode/p-type amorphous semiconductor/i-type a
-Si/n-type a-Si/electrode structure, and light is irradiated from the transparent electrode side. Transparent electrodes are made of ITO and SnO2 , especially
SnO 2 is preferred, and may be used by being vapor-deposited on a glass substrate in advance, or may be directly vapor-deposited on a p-type amorphous semiconductor. The thickness of the p-type amorphous semiconductor layer on the side irradiated with light is preferably about 30 Å to 300 Å.
The thickness of the i-type Si layer is not limited to 50 Å to 200 Å, but is about 2500 to 10000 Å.
The n-type a-Si layer is a layer for establishing ohmic contact, and its thickness is not limited, but is approximately 150 Å to 600 Å. Moreover, the n-type amorphous semiconductor of the present invention may be used instead of this n-type a-Si. Another typical structure is a transparent electrode/n-type amorphous semiconductor/i-type a-Si/p-type a-Si/electrode structure, in which light is irradiated from the transparent electrode side. The thickness of the n-type amorphous semiconductor on the side that is irradiated with light is approximately 30 mm.
Å to 300 Å preferably 50 Å to 200 Å, i-type a-Si
Although the thickness of the layer is not limited, a thickness of about 2,500 to 10,000 Å is usually used. The thickness of the p-type a-Si layer is not limited, but approximately 150 Å to 600 Å is used. Also, this p type a
-Si may be replaced by the p-type amorphous semiconductor of the present invention. The same applies to the material and vapor deposition method of the transparent electrode. Next, the effects of the present invention will be explained with reference to Examples. Glow discharge decomposition is performed using a high frequency of 14.56MHz using a quartz reaction tube with an inner diameter of 11cm. I-type a-Si is obtained by glow discharge decomposition of silane diluted with hydrogen at 2 to 10 Torr. For n-type a-Si, silane diluted with hydrogen and phosphine (pH 3 ) (pH 3 /SiH 4 = 0.5
% by mole) in a similar manner by glow discharge decomposition.
p-type a-Si (1-X) C x is silane diluted with hydrogen, methane (CH 4 ), diborane (B/(Si+C) = 0.1 atom
%) can be similarly obtained by glow discharge decomposition. Here, a-Si (1-X) C x has an atomic fraction x of 0.75 to
I set it to 0.05. The structure of the solar cell is that p - type a-Si (1-X) C x ,
I-type a-Si, n-type a-Si are deposited in this order, and finally
AM- 1 (100m
The solar cell characteristics were investigated using a solar simulator (W/cm 2 ). The substrate temperature during glow discharge was 250°C. Also, the i-layer is 5000 Å, the n-layer is 500 Å, and the p-type a-
The thickness of Si (1-X) C x is 135 Å. The solar cell characteristics depending on the film composition of p-type a-Si (1-X) C x are shown in the table below.
【表】
この表から判るように、短絡電流Jscと開放電
圧Vocに著しい改良効果が得られる。
これらのａ−Si(1-X)Cxの光学的バンドギヤツプ
Eg・optは、表に示すようにａ−Siよりも大きな
値を示しているので、これらのアモルフアス半導
体を窓材料にすればJscの増加は当然期待される。
ところがJscだけでなくVocも著しく改良される
という予想外の結果により、変換効率ηが大巾に
改良されている。この理由を明らかにするため、
十分に価電子制御された本発明のアモルフアス半
導体の拡散電位Vdと開放電圧Vocの関係を調べ
てみると第３図に示すように、アモルフアス半導
体の種類にかかわらず同一直線にプロツトされる
事が判つた。すなわちVdの増加とともにVocは
直線的に増加する。この事は、光学的バンドギヤ
ツプの大きなアモルフアス半導体を十分に価電子
制御してｐ−ｉ−ｎ接合光起電力素子の窓材料に
すれば、拡散電位の増加によつてVocも改良され
る事を示している。
以上示したように、Eg・optが約1.85eV以上で
ｐ−ｉ−ｎ接合の拡散電位Vdが1.1volt以上にな
るアモルフアス半導体を窓材料としたヘテロ接合
光起電力素子はVscだけでなくVocも著しく改良
される事を見い出し、その効果は、アモルフアス
半導体の種類に依存しないという驚くべきもので
ある。これらの結果はｎ型のアモルフアス半導体
から光照射しても全く同じである。[Table] As can be seen from this table, a significant improvement effect can be obtained on the short circuit current Jsc and the open circuit voltage Voc. The optical bandgap of these a-Si (1-X) C x
Since Eg·opt shows a larger value than a-Si as shown in the table, it is naturally expected that Jsc will increase if these amorphous semiconductors are used as window materials.
However, due to the unexpected result that not only Jsc but also Voc is significantly improved, the conversion efficiency η is greatly improved. To clarify the reason for this,
When we examine the relationship between the diffusion potential Vd and the open circuit voltage Voc of the amorphous semiconductor of the present invention, which has well-controlled valence electrons, we find that they are plotted on the same straight line regardless of the type of amorphous semiconductor, as shown in Figure 3. I understand. That is, Voc increases linearly as Vd increases. This means that if an amorphous semiconductor with a large optical bandgap is used as a window material for a pin junction photovoltaic element by sufficiently controlling its valence electrons, Voc can also be improved by increasing the diffusion potential. It shows. As shown above, a heterojunction photovoltaic element using an amorphous semiconductor as a window material, in which Eg・opt is approximately 1.85 eV or more and the pin junction diffusion potential Vd is 1.1 volt or more, has not only Vsc but also Voc It has been found that the results are significantly improved, and this effect is surprising because it does not depend on the type of amorphous semiconductor. These results are exactly the same even when light is irradiated from an n-type amorphous semiconductor.
第１図ａはｐ層側から光を照射するタイプの光
電素子を示す構造図、同ｂはｎ層側から光を照射
するタイプを示す構造図である。第２図は本発明
に係るヘテロｐ−ｉ−ｎ接合光起電力素子のエネ
ルギーバンドプロフアイルである。第３図はｐ型
のアモルフアス半導体を窓側にした場合の拡散電
位Vdと開放電圧の関係を示すグラフである。
１……ガラス、２……透明電極、３……ｐ型ア
モルフアス半導体、４……ｉ型ａ−Si半導体、５
……ｎ型半導体（例えばｎ型ａ−Si半導体）、６
……電極、７……電極基板、８……ｐ型ａ−Si半
導体、９……ｉ型ａ−Si半導体、１０……ｎ型ア
モルフアス半導体、１１……透明電極。
FIG. 1a is a structural diagram showing a type of photoelectric element that irradiates light from the p-layer side, and FIG. 1b is a structural diagram showing a type that irradiates light from the n-layer side. FIG. 2 is an energy band profile of a heterop-i-n junction photovoltaic device according to the present invention. FIG. 3 is a graph showing the relationship between the diffusion potential Vd and the open circuit voltage when a p-type amorphous semiconductor is placed on the window side. 1... Glass, 2... Transparent electrode, 3... P-type amorphous semiconductor, 4... I-type a-Si semiconductor, 5
... n-type semiconductor (e.g. n-type a-Si semiconductor), 6
... Electrode, 7 ... Electrode substrate, 8 ... P-type a-Si semiconductor, 9 ... I-type a-Si semiconductor, 10 ... N-type amorphous semiconductor, 11 ... Transparent electrode.
Claims (1)
電力素子において、ｐ又はｎ型の少なくとも光照
射する側のアモルフアス半導体は、光学的バンド
ギヤツプEg.optが約1.85eV〜約2.11eVの範囲内
にあり、かつ20℃における電気伝導度が約10-8
（Ω・cm）-1以上の、一般式ａ−Si(1-X)Cx（但し、
0.05＜ｘ＜0.8）で表されるアモルフアスシリコ
ンカーバイドであり、かつｐ−ｉ−ｎ接合の拡散
電位Vdが約1.1volts以上であることを特徴とする
ｐ−ｉ−ｎアモルフアスシリコン系光起電力素
子。 ２ 前記光照射する側のアモルフアスシリコンカ
ーバイドは、ｐ型であることを特徴とする特許請
求の範囲第１項記載のｐ−ｉ−ｎアモルフアスシ
リコン系光起電力素子。 ３ 前記光照射する側のアモルフアスシリコンカ
ーバイドは、ｎ型であることを特徴とする特許請
求の範囲第１項記載のｐ−ｉ−ｎアモルフアスシ
リコン系光起電力素子。[Claims] 1. In a p-i-n junction amorphous silicon-based photovoltaic device, the p- or n-type amorphous semiconductor at least on the side to which light is irradiated has an optical band gap Eg.opt of about 1.85 eV to about It is within the range of 2.11eV and the electrical conductivity at 20℃ is approximately 10 -8
(Ω・cm) -1 or more, general formula a-Si (1-X) C x (however,
0.05<x<0.8), and the pin junction has a diffusion potential Vd of about 1.1 volts or more. Electromotive force element. 2. The p-i-n amorphous silicon-based photovoltaic element according to claim 1, wherein the amorphous silicon carbide on the side to which the light is irradiated is p-type. 3. The p-i-n amorphous silicon-based photovoltaic element according to claim 1, wherein the amorphous silicon carbide on the side to which the light is irradiated is of n-type.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56066689A JPS57181176A (en) | 1981-04-30 | 1981-04-30 | High voltage amorphous semiconductor/amorphous silicon hetero junction photosensor |
| US06/266,064 US4388482A (en) | 1981-01-29 | 1981-05-19 | High-voltage photovoltaic cell having a heterojunction of amorphous semiconductor and amorphous silicon |
| JP2308025A JPH03188682A (en) | 1981-04-30 | 1990-11-13 | High potential amorphous semiconductor/amorphous silicon heterojunction photovoltaic element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56066689A JPS57181176A (en) | 1981-04-30 | 1981-04-30 | High voltage amorphous semiconductor/amorphous silicon hetero junction photosensor |
Related Child Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2308025A Division JPH03188682A (en) | 1981-04-30 | 1990-11-13 | High potential amorphous semiconductor/amorphous silicon heterojunction photovoltaic element |
| JP3164044A Division JPH0722633A (en) | 1991-02-15 | 1991-02-15 | High voltage amorphous semiconductor/amorphous silicon hetero junction semiconductor device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57181176A JPS57181176A (en) | 1982-11-08 |
| JPH0340515B2 true JPH0340515B2 (en) | 1991-06-19 |
Family
ID=13323147
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56066689A Granted JPS57181176A (en) | 1981-01-29 | 1981-04-30 | High voltage amorphous semiconductor/amorphous silicon hetero junction photosensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57181176A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5868046U (en) * | 1981-11-02 | 1983-05-09 | 工業技術院長 | photovoltaic element |
| JPH0758798B2 (en) * | 1984-06-08 | 1995-06-21 | 鐘淵化学工業株式会社 | Semiconductor device |
| JPS61232685A (en) * | 1985-04-09 | 1986-10-16 | Agency Of Ind Science & Technol | Amorphous silicon solar battery and manufacture thereof |
| US5055141A (en) * | 1990-01-19 | 1991-10-08 | Solarex Corporation | Enhancement of short-circuit current by use of wide bandgap n-layers in p-i-n amorphous silicon photovoltaic cells |
| JPH0722633A (en) * | 1991-02-15 | 1995-01-24 | Kanegafuchi Chem Ind Co Ltd | High voltage amorphous semiconductor/amorphous silicon hetero junction semiconductor device |
| JP3047666B2 (en) * | 1993-03-16 | 2000-05-29 | 富士電機株式会社 | Method for forming silicon oxide semiconductor film |
| JP4301372B2 (en) | 2005-04-01 | 2009-07-22 | 株式会社オーディオテクニカ | Acoustic tube, directional microphone, and method of manufacturing acoustic tube |
| WO2011001842A1 (en) | 2009-07-03 | 2011-01-06 | Semiconductor Energy Laboratory Co., Ltd. | Photoelectric conversion device and manufacturing method thereof |
| US9437758B2 (en) | 2011-02-21 | 2016-09-06 | Semiconductor Energy Laboratory Co., Ltd. | Photoelectric conversion device |
-
1981
- 1981-04-30 JP JP56066689A patent/JPS57181176A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57181176A (en) | 1982-11-08 |
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