JPH05218479A - Solar cell - Google Patents
Solar cellInfo
- Publication number
- JPH05218479A JPH05218479A JP4017413A JP1741392A JPH05218479A JP H05218479 A JPH05218479 A JP H05218479A JP 4017413 A JP4017413 A JP 4017413A JP 1741392 A JP1741392 A JP 1741392A JP H05218479 A JPH05218479 A JP H05218479A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- solar cell
- layer
- electrode layer
- semiconductor 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.)
- Granted
Links
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
- Y02E10/541—CuInSe2 material 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
- 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
- Y02E10/543—Solar cells from Group II-VI materials
-
- 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
Landscapes
- Photovoltaic Devices (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、光エネルギーを電気エ
ネルギーに変換する太陽電池に関し、特に電極層と半導
体層の窓層との接合構造を改良することにより、エネル
ギー変換効率の高効率化を図った太陽電池に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell for converting light energy into electric energy, and more particularly, to improve energy conversion efficiency by improving a junction structure between an electrode layer and a window layer of a semiconductor layer. It relates to the intended solar cell.
【０００２】[0002]
【従来の技術】従来、化合物薄膜を用いた太陽電池は、
例えば図３及び図４に示すように、広いバンドギャップ
を有する化合物半導体薄膜と狭いバンドギャップを持つ
化合物半導体薄膜のヘテロ接合で構成されており、前者
は太陽電池の窓層３３、４３として機能すると共に、後
者は太陽電池の吸収層３４、４４として機能する。2. Description of the Related Art Conventionally, a solar cell using a compound thin film is
For example, as shown in FIGS. 3 and 4, the compound semiconductor thin film having a wide band gap and the compound semiconductor thin film having a narrow band gap are used as a heterojunction, and the former functions as the window layers 33 and 43 of the solar cell. Together, the latter functions as the absorption layers 34, 44 of the solar cell.
【０００３】このような太陽電池において高いエネルギ
ー変換効率を得るためには、(1) より多くの光電流を得
るための光学的な最適設計を行うこと、(2) 太陽電池を
構成する各層の結晶性、特に吸収層の結晶性が高品質で
あること、(3) 各層の界面においてキャリアの再結合の
ない高品質なヘテロ接合を作ること、等が必要となる。In order to obtain a high energy conversion efficiency in such a solar cell, (1) an optical optimum design for obtaining a larger photocurrent is performed, and (2) each layer constituting the solar cell. The crystallinity, especially the crystallinity of the absorption layer, must be high, and (3) a high-quality heterojunction without carrier recombination at the interface between the layers must be formed.
【０００４】ヘテロ接合の品質は、その作製方法や膜形
成の順序と関係が深い。例えば、従来のＣｄＳ／ＣｄＴ
ｅ系やＣｄＳ／ＣｕＩｎＳｅ2 系の構成において、優れ
たヘテロ接合が得られている。The quality of the heterojunction is closely related to its manufacturing method and the order of film formation. For example, conventional CdS / CdT
An excellent heterojunction has been obtained in the e-based and CdS / CuInSe 2 -based configurations.
【０００５】図３は、従来の太陽電池の一例の断面図で
ある。透明絶縁性基板３１の上に、順次、透明性のＳｎ
Ｏ2 、ＩＴＯ又はＺｎＯ等からなる第１電極層３２、広
いバンドギャップを有するＺｎＣｄＳからなる窓層３
３、光吸収用半導体層３４、第２電極層３５が積層され
ており、ＺｎＣｄＳと光吸収用半導体層とのヘテロ接合
の試みによって、太陽光の短波長光に対する感度向上が
図られている。FIG. 3 is a sectional view of an example of a conventional solar cell. On the transparent insulating substrate 31, a transparent Sn film is sequentially formed.
The first electrode layer 32 made of O 2 , ITO, ZnO or the like, and the window layer 3 made of ZnCdS having a wide band gap.
3, the light-absorbing semiconductor layer 34, and the second electrode layer 35 are laminated, and the heterojunction between ZnCdS and the light-absorbing semiconductor layer is attempted to improve the sensitivity of sunlight to short-wavelength light.
【０００６】図４は、従来の太陽電池の他の例の断面図
である。透明絶縁性基板１の上に、順次、透明性のＳｎ
Ｏ2 、ＩＴＯ又はＺｎＯ等からなる第１電極層４２、広
いバンドギャップを有するＣｄＳからなる化合物半導体
薄膜４３ａ、ＣｄＳ(1-x) Ｔｅx （但し、０≦ｘ≦１）
からなる傾斜組成層４３ｂ、ＣｄＴｅからなる光吸収用
半導体層４４、第２電極層４５が積層されており、窓層
として機能する化合物半導体薄膜４３ａと吸収層として
機能する光吸収用半導体層４４との間に、徐々に窓層の
組成に近いものから吸収層の組成に近いものに変化させ
た傾斜組成層４３ｂを介在させることにより、より優れ
たヘテロ接合を得ている。FIG. 4 is a sectional view of another example of a conventional solar cell. On the transparent insulating substrate 1, transparent Sn is sequentially formed.
A first electrode layer 42 made of O 2 , ITO, ZnO or the like, a compound semiconductor thin film 43a made of CdS having a wide band gap, CdS (1-x) Te x (where 0 ≦ x ≦ 1)
The gradient composition layer 43b made of CdTe, the light absorption semiconductor layer 44 made of CdTe, and the second electrode layer 45 are laminated, and the compound semiconductor thin film 43a functioning as a window layer and the light absorption semiconductor layer 44 functioning as an absorption layer. A more excellent heterojunction is obtained by interposing a graded composition layer 43b gradually changing from a composition close to that of the window layer to a composition close to that of the absorption layer.
【０００７】[0007]
【発明が解決すべき課題】従来の化合物薄膜ヘテロ接合
型太陽電池において、共通する課題の１つは、窓層のバ
ンドギャップによってその太陽電池における短波長感度
が殆ど決定されてしまうことである。In the conventional compound thin film heterojunction type solar cell, one of the common problems is that the bandgap of the window layer almost determines the short wavelength sensitivity of the solar cell.
【０００８】図５は、図３及び図４に示した従来の太陽
電池の窓層のバンドギャップ付近における量子効率のグ
ラフである。グラフ中で破線で示した図３の太陽電池
は、窓層の広バンドギャップ化によって得られる光電流
を増加させることができるが、窓層としてＣｄＳを用い
た場合に比べて、得られる開放端電圧が少し低下する傾
向があり、結果としてエネルギー変換効率が大きく向上
するまでには至っていない。FIG. 5 is a graph of the quantum efficiency near the band gap of the window layer of the conventional solar cell shown in FIGS. 3 and 4. The solar cell of FIG. 3 indicated by the broken line in the graph can increase the photocurrent obtained by widening the band gap of the window layer, but the obtained open end is larger than that obtained when CdS is used as the window layer. The voltage tends to decrease a little, and as a result, the energy conversion efficiency has not been greatly improved.
【０００９】また、グラフ中で実線で示した図３の太陽
電池は、開放端電圧が少し増加する傾向があるが、短波
長の感度が窓層として用いたＣｄＳのバンドギャップに
より殆ど決定されているようなスペクトルを示してお
り、結果としてエネルギー変換効率が大きく向上するま
でには至っていない。In the solar cell of FIG. 3 shown by the solid line in the graph, the open circuit voltage tends to increase a little, but the sensitivity of short wavelength is almost determined by the band gap of CdS used as the window layer. It shows a spectrum like that, and as a result, the energy conversion efficiency has not been greatly improved.
【００１０】このような原因として、図３の太陽電池の
場合は、ＺｎＣｄＳ薄膜と光吸収層半導体で形成された
ヘテロ接合の品質が、ＣｄＳ薄膜と光吸収層半導体との
ヘテロ接合に比べて低下していることが予想される。ま
た、図４の太陽電池の場合は、ＣｄＳ薄膜の表面で生成
される電子−正孔対が、光吸収層内に存在する空乏層ま
で導かれ難いエネルギーバンド構造になっていることが
予想される。As a cause of this, in the case of the solar cell of FIG. 3, the quality of the heterojunction formed by the ZnCdS thin film and the light absorption layer semiconductor is lower than that of the heterojunction between the CdS thin film and the light absorption layer semiconductor. It is expected that Further, in the case of the solar cell of FIG. 4, it is expected that electron-hole pairs generated on the surface of the CdS thin film have an energy band structure in which it is difficult to lead to the depletion layer existing in the light absorption layer. It
【００１１】以下、図４の太陽電池の場合を更に詳しく
説明する。図４に示した従来の太陽電池のエネルギーバ
ンド構造は、図６に示すようなバンド構造であることが
推測される。即ち、価電子帯の正孔は好適な内部電界に
より円滑な移動が可能であるが、伝導帯の電子について
は、図中のＰ点近傍が極小部を形成しているため、その
部分の電子濃度が高くなって正孔との再結合が促進さ
れ、あまり好ましくないバンド構造となっている。太陽
電池の構造として図４に示したような傾斜組成構造を窓
層と光吸収層の間に介在させる場合、多くの場合に上述
した不都合が生ずる傾向がある。The case of the solar cell shown in FIG. 4 will be described in more detail below. It is assumed that the energy band structure of the conventional solar cell shown in FIG. 4 is a band structure as shown in FIG. That is, the holes in the valence band can move smoothly by a suitable internal electric field, but the electrons in the conduction band form a local minimum in the vicinity of point P in the figure, so the electrons in that part The increased concentration promotes recombination with holes, resulting in a band structure that is not very desirable. When the graded composition structure as shown in FIG. 4 is interposed between the window layer and the light absorption layer as the structure of the solar cell, the above-mentioned disadvantage tends to occur in many cases.
【００１２】図７は、太陽電池の各層において励起され
た電子−正孔対生成数の分布を厚さ方向について示した
グラフである。グラフ中、実線Ａは図３の太陽電池であ
り、破線Ｂは図４の太陽電池である。因みに、二点鎖線
Ｃは本発明の太陽電池である。図３及び図４の太陽電池
においては、化合物薄膜の少数キャリアの拡散長は非常
に短いことが予想されるため、光線が入射する表面近
傍、即ちグラフ中Ｓで示した窓層の表面近傍における生
成キャリアは、上述と同様にキャリア対の再結合が促進
され、光電流として殆ど獲得できないことという課題が
あった。FIG. 7 is a graph showing the distribution of the number of generated electron-hole pairs excited in each layer of the solar cell in the thickness direction. In the graph, the solid line A is the solar cell of FIG. 3, and the broken line B is the solar cell of FIG. Incidentally, the chain double-dashed line C is the solar cell of the present invention. In the solar cells of FIGS. 3 and 4, the diffusion length of the minority carriers in the compound thin film is expected to be very short, and therefore, in the vicinity of the surface on which the light beam is incident, that is, in the vicinity of the surface of the window layer indicated by S in the graphs. Similar to the above, the generated carriers have a problem that the recombination of carrier pairs is promoted and they are hardly obtained as a photocurrent.
【００１３】本発明は、前記課題を解決するため、従来
の太陽電池では殆ど獲得できなかった窓層の表面近傍に
生じるキャリア対を、効率良く光電流として取り出すこ
とができる太陽電池を提供することを目的とする。In order to solve the above problems, the present invention provides a solar cell capable of efficiently extracting a carrier pair generated in the vicinity of the surface of a window layer, which was hardly obtained by a conventional solar cell, as a photocurrent. With the goal.
【００１４】[0014]
【課題を解決するための手段】前記目的を達成するた
め、本発明の太陽電池は、透明絶縁性基板の上に、順
次、透明性の第１電極層、ＺｎＳ薄膜、ＣｄＳ薄膜、光
吸収用半導体層、第２電極層が積層されていることを特
徴とする。In order to achieve the above object, the solar cell of the present invention comprises a transparent insulating substrate, a transparent first electrode layer, a ZnS thin film, a CdS thin film, and a light-absorbing layer formed in this order. The semiconductor layer and the second electrode layer are laminated.
【００１５】また、本発明の太陽電池は、絶縁性基板の
上に、順次、第１電極層、光吸収用半導体層、ＣｄＳ薄
膜、ＺｎＳ薄膜、透明性の第２電極層が積層されている
ことを特徴とする。Further, in the solar cell of the present invention, the first electrode layer, the light absorbing semiconductor layer, the CdS thin film, the ZnS thin film, and the transparent second electrode layer are sequentially laminated on the insulating substrate. It is characterized by
【００１６】前記構成において、ＺｎＳ薄膜の電極側
に、ｎ型ドーパントが導入されていることが好ましい。
また、前記構成において、光吸収用半導体層が、ＩＩ−
ＶＩ族化合物半導体で形成されていることが好ましい。In the above structure, it is preferable that an n-type dopant is introduced to the electrode side of the ZnS thin film.
In the above structure, the light absorption semiconductor layer is II-
It is preferably formed of a Group VI compound semiconductor.
【００１７】また、前記構成において、光吸収用半導体
層が、ＣｄＴｅで形成されていることが好ましい。ま
た、前記構成において、光吸収用半導体層が、カルコパ
イライト型半導体で形成されていることが好ましい。Further, in the above structure, it is preferable that the light absorbing semiconductor layer is formed of CdTe. Further, in the above structure, the light absorbing semiconductor layer is preferably formed of a chalcopyrite type semiconductor.
【００１８】また、前記構成において、光吸収用半導体
層が、ＣｕＩｎＳｅ2 で形成されていることが好まし
い。In the above structure, it is preferable that the light absorbing semiconductor layer is made of CuInSe 2 .
【００１９】[0019]
【作用】前記構成によれば、透明絶縁性基板の上に、順
次、透明性の第１電極層、ＺｎＳ薄膜、ＣｄＳ薄膜、光
吸収用半導体層、第２電極層が積層され、太陽電池の窓
層としてＺｎＳ薄膜及びＣｄＳ薄膜からなる積層膜で形
成されていることにより、光吸収用半導体層として優れ
たＣｄＴｅやＣｕＩｎＳｅ2 等とのヘテロ接合が高品質
となると共に、窓層の内部にも内部電界が生ずるため、
電子−正孔対が効率良く光電流として取り出される。According to the above construction, the transparent first electrode layer, the ZnS thin film, the CdS thin film, the light absorbing semiconductor layer, and the second electrode layer are sequentially laminated on the transparent insulating substrate, and Since the window layer is formed of a laminated film including a ZnS thin film and a CdS thin film, a high quality heterojunction with CdTe, CuInSe 2 or the like, which is excellent as a light-absorbing semiconductor layer, becomes high in quality, and also inside the window layer. Since an internal electric field is generated,
The electron-hole pairs are efficiently extracted as photocurrent.
【００２０】更に詳説すると、図８及び図９は本発明に
係る太陽電池のエネルギーバンド構造図である。図８に
おいて、窓層がＺｎＳ薄膜及びＣｄＳ薄膜からなる積層
膜で形成されていることにより、価電子帯のエネルギー
準位に傾斜が生じて、窓層において生成したキャリア対
の正孔が光吸収層の方に移動し易くなるため、再結合が
阻止される。特に、図７の二点鎖線Ｃの領域Ｔに示すよ
うに、ＺｎＳ薄膜とＣｄＳ薄膜の界面近傍では、比較的
多くの電子−正孔対が生成されるため、この電子−正孔
対が効率良く取り出されることになる。8 and 9 are energy band structure diagrams of the solar cell according to the present invention. In FIG. 8, since the window layer is formed of a laminated film including a ZnS thin film and a CdS thin film, an energy level in the valence band is inclined, and holes of carrier pairs generated in the window layer absorb light. Recombination is prevented because it is easier to move towards the layers. In particular, as shown in the region T of the chain double-dashed line C in FIG. 7, a relatively large number of electron-hole pairs are generated in the vicinity of the interface between the ZnS thin film and the CdS thin film. It is often taken out.
【００２１】また、ＺｎＳ薄膜及びＣｄＳ薄膜からなる
積層膜は、ＺｎＳとＣｄＳの電子親和力がほぼ同じであ
ることから、図６のＰ点に示したような伝導帯の極小部
は本質的に生じにくい。更に、ＺｎＳ薄膜の電極側、即
ちＣｄＳ薄膜界面の反対側の近傍のみに、ｎ型ドーパン
トを導入することにより、図９に示すように窓層の伝導
帯及び価電子帯に傾斜が生じて、電子がＺｎＳ薄膜の電
極側により移動し易くなり、正孔は光吸収層の方により
移動し易くなるため、より多くの光電流を取り出すこと
ができる。Further, in the laminated film composed of the ZnS thin film and the CdS thin film, since the electron affinity of ZnS and CdS are almost the same, the minimum portion of the conduction band as shown at point P in FIG. 6 is essentially generated. Hateful. Further, by introducing the n-type dopant only in the vicinity of the electrode side of the ZnS thin film, that is, the side opposite to the interface of the CdS thin film, the conduction band and the valence band of the window layer are inclined as shown in FIG. Electrons are more likely to move to the electrode side of the ZnS thin film, and holes are more likely to be moved to the light absorption layer, so that more photocurrent can be taken out.
【００２２】また、前記した別の構成によれば、絶縁性
基板の上に、順次、第１電極層、光吸収用半導体層、Ｃ
ｄＳ薄膜、ＺｎＳ薄膜、透明性の第２電極層が積層され
ていることにより、ＣｄＳ薄膜及びＺｎＳ薄膜からなる
窓層における電子と正孔が前述と同様の現象を示し、よ
り多くの光電流を取り出すことができる。更に、透明性
の第２電極層としてインジウム・スズ酸化物（以下、
「ＩＴＯ」と略す）を用いて、熱拡散処理を施すと、Ｉ
ＴＯの中のＩｎがｎ型ドーパントとしてＺｎＳ薄膜の電
極側に拡散するため、ｎ型ドーパントの導入が容易に行
える。Further, according to the above-mentioned another structure, the first electrode layer, the light absorbing semiconductor layer, and the C layer are sequentially formed on the insulating substrate.
By stacking the dS thin film, the ZnS thin film, and the transparent second electrode layer, electrons and holes in the window layer composed of the CdS thin film and the ZnS thin film exhibit the same phenomenon as described above, and more photocurrent is generated. You can take it out. Furthermore, as a transparent second electrode layer, indium tin oxide (hereinafter,
When a thermal diffusion process is performed using (ITO)
Since In in TO diffuses to the electrode side of the ZnS thin film as an n-type dopant, the n-type dopant can be easily introduced.
【００２３】また、前記構成において、光吸収用半導体
層がＩＩ−ＶＩ族化合物半導体で形成されていることに
より、窓層と光吸収層とのヘテロ接合特性が良好となる
ため、より高い開放端電圧を得ることが可能となる。Further, in the above structure, since the light absorption semiconductor layer is made of a II-VI group compound semiconductor, the heterojunction characteristic between the window layer and the light absorption layer is improved, so that a higher open end is obtained. It is possible to obtain the voltage.
【００２４】また、前記構成において、光吸収用半導体
層がＣｄＴｅで形成されていることにより、更に優れた
ヘテロ接合が得られるようになるため、更に高い開放端
電圧を得ることが可能となる。Further, in the above structure, since the light absorption semiconductor layer is made of CdTe, a more excellent heterojunction can be obtained, so that a higher open circuit voltage can be obtained.
【００２５】また、前記構成において、光吸収用半導体
層がカルコパイライト型半導体で形成されていることに
より、窓層と光吸収層のヘテロ接合特性が向上するた
め、開放端電圧を大きくすることが可能となる。Further, in the above structure, since the light absorbing semiconductor layer is formed of chalcopyrite type semiconductor, the heterojunction characteristic of the window layer and the light absorbing layer is improved, so that the open circuit voltage can be increased. It will be possible.
【００２６】また、前記構成において、光吸収用半導体
層がＣｕＩｎＳｅ2 で形成されていることにより、更に
窓層と光吸収層のヘテロ接合特性が向上するため、更に
開放端電圧を大きくすることが可能となる。Further, in the above structure, since the light absorbing semiconductor layer is made of CuInSe 2 , the heterojunction characteristic of the window layer and the light absorbing layer is further improved, and therefore the open-ended voltage can be further increased. It will be possible.
【００２７】[0027]
【実施例】以下、本発明の実施例について図面を参照し
ながら説明する。 （実施例１）図１は、本発明の太陽電池の一実施例の断
面図である。ガラス基板等の透明絶縁性基板１１の上
に、熱的プロセスを経てもＺｎＳと激しく反応しない材
料、例えばＩＴＯやＳｎＯ2 等からなる透明性の第１電
極層１２がスパッター蒸着法を用いて形成され、その上
にＺｎＳ薄膜１３ａが真空蒸着法を用いて０．２μｍ程
度の膜厚で形成され、続いてＣｄＳ薄膜１３ｂが真空蒸
着法を用いて０．２μｍ程度の膜厚で形成され、ＺｎＳ
薄膜１３ａ及びＣｄＳ薄膜１３ｂからなる積層膜が太陽
電池の窓層１３として機能する。Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view of an embodiment of the solar cell of the present invention. On the transparent insulating substrate 11 such as a glass substrate, a transparent first electrode layer 12 made of a material that does not react violently with ZnS even if it undergoes a thermal process, for example, ITO or SnO 2 is formed by the sputter deposition method. ZnS thin film 13a is formed thereon by vacuum deposition to a film thickness of about 0.2 μm, and then CdS thin film 13b is formed thereon by a vacuum deposition process to a film thickness of about 0.2 μm.
A laminated film including the thin film 13a and the CdS thin film 13b functions as the window layer 13 of the solar cell.
【００２８】次に、光吸収用半導体層１４として、ｐ型
のＣｄＴｅ薄膜又はＣｕＩｎＳｅ2薄膜が真空蒸着法を
用いて３μｍ程度の膜厚で形成され、その上にＡｕやＮ
ｉ等の第２電極層１５が電子ビーム蒸着法を用いて形成
され、光吸収用半導体層１４とのオーミック接触を得て
いる。このようにして図８に示したバンド構造を有する
本発明の太陽電池を得ることができる。Next, as the light absorbing semiconductor layer 14, a p-type CdTe thin film or a CuInSe 2 thin film is formed to a thickness of about 3 μm by the vacuum evaporation method, and Au or N is formed thereon.
The second electrode layer 15 such as i is formed by using the electron beam evaporation method to obtain ohmic contact with the light absorbing semiconductor layer 14. In this way, the solar cell of the present invention having the band structure shown in FIG. 8 can be obtained.
【００２９】（実施例２）図２は、本発明の太陽電池の
他の実施例の断面図である。ガラス基板等の絶縁性基板
２１の上に、ＡｕやＮｉ等の第１電極層２２が電子ビー
ム蒸着法を用いて形成され、その上に光吸収用半導体層
２４として、ｐ型のＣｄＴｅ薄膜又はＣｕＩｎＳｅ2 薄
膜が真空蒸着法を用いて３μｍ程度の膜厚で形成され
る。(Embodiment 2) FIG. 2 is a sectional view of another embodiment of the solar cell of the present invention. A first electrode layer 22 made of Au, Ni, or the like is formed on an insulating substrate 21 such as a glass substrate by using an electron beam evaporation method, and a p-type CdTe thin film or a light absorption semiconductor layer 24 is formed thereon. A CuInSe 2 thin film is formed with a film thickness of about 3 μm by using a vacuum evaporation method.
【００３０】次に、ＣｄＳ薄膜２３ｂが真空蒸着法を用
いて０．２μｍ程度の膜厚で形成され、続いてＺｎＳ薄
膜２３ａが真空蒸着法を用いて０．２μｍ程度の膜厚で
形成され、ＺｎＳ薄膜２３ａ及びＣｄＳ薄膜２３ｂから
なる積層膜が太陽電池の窓層２３として機能する。更に
その上に、ＩＴＯやＳｎＯ2 等からなる透明性の第２電
極層２５がスパッター蒸着法を用いて形成される。この
ようにして図８に示したバンド構造を有する本発明の太
陽電池を得ることができる。Next, the CdS thin film 23b is formed to a thickness of about 0.2 μm by using the vacuum evaporation method, and the ZnS thin film 23a is subsequently formed to a thickness of about 0.2 μm by using the vacuum evaporation method. A laminated film composed of the ZnS thin film 23a and the CdS thin film 23b functions as the window layer 23 of the solar cell. Further thereon, a transparent second electrode layer 25 made of ITO, SnO 2 or the like is formed by using the sputter deposition method. In this way, the solar cell of the present invention having the band structure shown in FIG. 8 can be obtained.
【００３１】（実施例３）前述した実施例１において、
透明性の第１電極層２としてＩＴＯを用いて、その上に
ＺｎＳ薄膜を０．２μｍ程度の膜厚で形成した後、５５
０℃〜６５０℃の温度で熱処理を施し、以後、実施例１
で説明した手順で、ＣｄＳ薄膜１３ｂ、光吸収用半導体
層１４、第２電極層１５の各層を形成する。(Third Embodiment) In the first embodiment described above,
After ITO was used as the transparent first electrode layer 2 and a ZnS thin film was formed thereon with a thickness of about 0.2 μm, 55
Heat treatment was performed at a temperature of 0 ° C. to 650 ° C., and thereafter, in Example 1.
The CdS thin film 13b, the light absorbing semiconductor layer 14, and the second electrode layer 15 are formed by the procedure described in the above.
【００３２】このような熱処理により、ＺｎＳ薄膜の電
極側に、ＩＴＯ中のＩｎがｎ型ドーパントとして熱拡散
するため、図９に示したバンド構造を有する本発明の太
陽電池を得ることができる。By such heat treatment, In in ITO is thermally diffused as an n-type dopant on the electrode side of the ZnS thin film, so that the solar cell of the present invention having the band structure shown in FIG. 9 can be obtained.
【００３３】次に、各実施例で得られた太陽電池の特性
評価について説明する。図１０は、太陽電池の電流−電
圧特性（Ｉ−Ｖ特性）のグラフである。グラフ中、Ａは
図３に示した従来の太陽電池、Ｂは図４に示した従来の
太陽電池、Ｃは本発明の太陽電池であり、いずれも光吸
収用半導体層がＣｄＴｅ薄膜で形成されているものであ
る。また、Ｄは図３に示した従来の太陽電池、Ｅは本発
明の太陽電池であり、いずれも光吸収用半導体層がＣｕ
ＩｎＳｅ2 薄膜で形成されているものである。Next, the characteristic evaluation of the solar cells obtained in the respective examples will be described. FIG. 10 is a graph of current-voltage characteristics (IV characteristics) of the solar cell. In the graph, A is the conventional solar cell shown in FIG. 3, B is the conventional solar cell shown in FIG. 4, and C is the solar cell of the present invention. In both cases, the light absorption semiconductor layer is formed of a CdTe thin film. Is what Further, D is the conventional solar cell shown in FIG. 3, E is the solar cell of the present invention, and the light absorption semiconductor layer is Cu.
It is formed of an InSe 2 thin film.
【００３４】グラフを見ると、太陽電池の窓層としてＺ
ｎＣｄＳ薄膜を用いた従来のものと比較して、本発明の
ＺｎＳ／ＣｄＳ積層膜の構成のほうが、より大きい開放
端電圧を出力することが理解される。また、窓層として
ＣｄＳ薄膜及びＣｄＳ(1-x)Ｔｅx 傾斜組成層からなる
積層膜を用いた従来のものと比較して、本発明のＺｎＳ
／ＣｄＳ積層膜の構成のほうが、より多い光電流を出力
することが理解される。また、エネルギー変換効率に関
して、従来の太陽電池は１０％〜１２％であったが、本
発明の太陽電池は１４％という高い変換効率が得られ
た。Looking at the graph, Z is used as the window layer of the solar cell.
It is understood that the structure of the ZnS / CdS laminated film of the present invention outputs a larger open-ended voltage as compared with the conventional one using the nCdS thin film. In addition, the ZnS of the present invention is compared with a conventional one using a laminated film including a CdS thin film and a CdS (1-x) Te x gradient composition layer as a window layer.
It is understood that the structure of the / CdS laminated film outputs more photocurrent. Regarding the energy conversion efficiency, the conventional solar cell has a conversion efficiency of 10% to 12%, but the solar cell of the present invention has a high conversion efficiency of 14%.
【００３５】[0035]
【発明の効果】以上、詳説したように、本発明の太陽電
池は、窓層としてＺｎＳ薄膜及びＣｄＳ薄膜からなる積
層膜で形成されていることにより、光吸収用半導体層と
のヘテロ接合が高品質となると共に、窓層の内部にも内
部電界が生じて電子−正孔対が効率良く光電流として取
り出されるため、高いエネルギー変換効率を有する太陽
電池を得ることができる。As described above in detail, the solar cell of the present invention has a high heterojunction with the light-absorbing semiconductor layer because the solar cell of the present invention is formed of the laminated film including the ZnS thin film and the CdS thin film as the window layer. In addition to high quality, an internal electric field is generated inside the window layer, and electron-hole pairs are efficiently extracted as photocurrents, so that a solar cell having high energy conversion efficiency can be obtained.
【図１】本発明の太陽電池の一実施例の断面図である。FIG. 1 is a cross-sectional view of an embodiment of the solar cell of the present invention.
【図２】本発明の太陽電池の他の実施例の断面図であ
る。FIG. 2 is a sectional view of another embodiment of the solar cell of the present invention.
【図３】従来の太陽電池の一例の断面図である。FIG. 3 is a cross-sectional view of an example of a conventional solar cell.
【図４】従来の太陽電池の他の例の断面図である。FIG. 4 is a cross-sectional view of another example of a conventional solar cell.
【図５】図３及び図４に示した従来の太陽電池の窓層の
バンドギャップ付近における量子効率のグラフである。FIG. 5 is a graph of quantum efficiency in the vicinity of the band gap of the window layer of the conventional solar cell shown in FIGS. 3 and 4.
【図６】図４に示した従来の太陽電池のエネルギーバン
ド構造図である。6 is an energy band structure diagram of the conventional solar cell shown in FIG.
【図７】太陽電池の各層において励起された電子−正孔
対生成数の分布を厚さ方向について示したグラフであ
る。FIG. 7 is a graph showing the distribution of the number of generated electron-hole pairs excited in each layer of the solar cell in the thickness direction.
【図８】本発明の太陽電池のエネルギーバンド構造図の
一例である。FIG. 8 is an example of an energy band structure diagram of the solar cell of the present invention.
【図９】本発明の太陽電池のエネルギーバンド構造図の
他の例である。FIG. 9 is another example of the energy band structure diagram of the solar cell of the present invention.
【図１０】太陽電池の電流−電圧特性（Ｉ−Ｖ特性）の
グラフである。FIG. 10 is a graph of current-voltage characteristics (IV characteristics) of the solar cell.
１１、３１、４１ 透明絶縁性基板 ２１ 絶縁性基板 １２、２２、３２、４２ 第１電極層 １３、２３、４３ 窓層 １３ａ、２３ａ ＺｎＳ薄膜 １３ｂ、２３ｂ ＣｄＳ薄膜 ３３ ＺｎＣｄＳ薄膜（窓層） ４３ａ ＣｄＳ薄膜 ４３ｂ ＣｄＳ(1-x) Ｔｅx 傾斜組成層 １４、２４、３４、４４ 光吸収用半導体層 １５、２５、３５、４５ 第２電極層11, 31, 41 Transparent insulating substrate 21 Insulating substrate 12, 22, 32, 42 First electrode layer 13, 23, 43 Window layer 13a, 23a ZnS thin film 13b, 23b CdS thin film 33 ZnCdS thin film (window layer) 43a CdS Thin film 43b CdS (1-x) Te x gradient composition layer 14, 24, 34, 44 Light absorbing semiconductor layer 15, 25, 35, 45 Second electrode layer
Claims (7)
第１電極層、ＺｎＳ薄膜、ＣｄＳ薄膜、光吸収用半導体
層、第２電極層が積層されている太陽電池。1. A solar cell in which a transparent first electrode layer, a ZnS thin film, a CdS thin film, a light absorbing semiconductor layer, and a second electrode layer are sequentially laminated on a transparent insulating substrate.
光吸収用半導体層、ＣｄＳ薄膜、ＺｎＳ薄膜、透明性の
第２電極層が積層されている太陽電池。2. A first electrode layer is sequentially formed on the insulating substrate,
A solar cell in which a light-absorbing semiconductor layer, a CdS thin film, a ZnS thin film, and a transparent second electrode layer are laminated.
が導入されている請求項１又は２に記載の太陽電池。3. The solar cell according to claim 1, wherein an n-type dopant is introduced on the electrode side of the ZnS thin film.
物半導体で形成されている請求項１又は２に記載の太陽
電池。4. The solar cell according to claim 1, wherein the light absorption semiconductor layer is formed of a II-VI group compound semiconductor.
れている請求項４に記載の太陽電池。5. The solar cell according to claim 4, wherein the light absorption semiconductor layer is formed of CdTe.
型半導体で形成されている請求項１又は２に記載の太陽
電池。6. The solar cell according to claim 1, wherein the light absorbing semiconductor layer is formed of a chalcopyrite type semiconductor.
形成されている請求項６に記載の太陽電池。7. The solar cell according to claim 6, wherein the light absorption semiconductor layer is formed of CuInSe 2 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04017413A JP3130993B2 (en) | 1992-02-03 | 1992-02-03 | Solar cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04017413A JP3130993B2 (en) | 1992-02-03 | 1992-02-03 | Solar cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05218479A true JPH05218479A (en) | 1993-08-27 |
| JP3130993B2 JP3130993B2 (en) | 2001-01-31 |
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ID=11943325
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04017413A Expired - Fee Related JP3130993B2 (en) | 1992-02-03 | 1992-02-03 | Solar cell |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1981089A2 (en) | 2002-10-04 | 2008-10-15 | Sumitomo Metal Mining Co., Ltd. | Transparent electrode film based on indium oxide with titanium and tungsten admixtures and manufacturing method thereof |
| WO2009110092A1 (en) * | 2008-03-07 | 2009-09-11 | 昭和シェル石油株式会社 | Laminated structuer of cis-type solar battery and integrated structure |
| JP2012028650A (en) * | 2010-07-26 | 2012-02-09 | Toyota Central R&D Labs Inc | Photoelectric element and manufacturing method thereof |
| CN102751345A (en) * | 2012-05-25 | 2012-10-24 | 陕西师范大学 | Cadmium telluride/ cadmium sulfide solar cell |
| JPWO2011052646A1 (en) * | 2009-10-28 | 2013-03-21 | 京セラ株式会社 | Photoelectric conversion device, photoelectric conversion module, and method of manufacturing photoelectric conversion device |
-
1992
- 1992-02-03 JP JP04017413A patent/JP3130993B2/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1981089A2 (en) | 2002-10-04 | 2008-10-15 | Sumitomo Metal Mining Co., Ltd. | Transparent electrode film based on indium oxide with titanium and tungsten admixtures and manufacturing method thereof |
| US7507357B2 (en) | 2002-10-04 | 2009-03-24 | Sumitomo Metal Mining Co., Ltd. | Transparent oxide electrode film and manufacturing method thereof, transparent electroconductive base material, solar cell and photo detection element |
| US7575698B2 (en) | 2002-10-04 | 2009-08-18 | Sumitomo Metal Mining Co., Ltd. | TI and W containing transparent oxide electrode film |
| WO2009110092A1 (en) * | 2008-03-07 | 2009-09-11 | 昭和シェル石油株式会社 | Laminated structuer of cis-type solar battery and integrated structure |
| JPWO2011052646A1 (en) * | 2009-10-28 | 2013-03-21 | 京セラ株式会社 | Photoelectric conversion device, photoelectric conversion module, and method of manufacturing photoelectric conversion device |
| JP2012028650A (en) * | 2010-07-26 | 2012-02-09 | Toyota Central R&D Labs Inc | Photoelectric element and manufacturing method thereof |
| CN102751345A (en) * | 2012-05-25 | 2012-10-24 | 陕西师范大学 | Cadmium telluride/ cadmium sulfide solar cell |
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| Publication number | Publication date |
|---|---|
| JP3130993B2 (en) | 2001-01-31 |
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