JPH0750793B2 - Thin film photoelectric conversion element - Google Patents
Thin film photoelectric conversion elementInfo
- Publication number
- JPH0750793B2 JPH0750793B2 JP60119854A JP11985485A JPH0750793B2 JP H0750793 B2 JPH0750793 B2 JP H0750793B2 JP 60119854 A JP60119854 A JP 60119854A JP 11985485 A JP11985485 A JP 11985485A JP H0750793 B2 JPH0750793 B2 JP H0750793B2
- Authority
- JP
- Japan
- Prior art keywords
- photoelectric conversion
- thin film
- electrode layer
- layer
- conversion element
- 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
- 238000006243 chemical reaction Methods 0.000 title claims description 54
- 239000010409 thin film Substances 0.000 title claims description 26
- 239000000758 substrate Substances 0.000 claims description 44
- 239000004065 semiconductor Substances 0.000 claims description 31
- 239000011521 glass Substances 0.000 claims description 29
- 238000005530 etching Methods 0.000 claims description 6
- 125000005842 heteroatom Chemical group 0.000 claims description 2
- 238000003754 machining Methods 0.000 claims description 2
- 238000000465 moulding Methods 0.000 claims 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 28
- 238000000034 method Methods 0.000 description 11
- 239000010408 film Substances 0.000 description 10
- 230000003287 optical effect Effects 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 229910006404 SnO 2 Inorganic materials 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000005229 chemical vapour deposition Methods 0.000 description 4
- 230000010354 integration Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000005268 plasma chemical vapour deposition Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000007740 vapor deposition Methods 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910017855 NH 4 F Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 230000031700 light absorption Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000001039 wet etching 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
- H01L31/02—Details
- H01L31/0236—Special surface textures
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Photovoltaic Devices (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は薄膜光電変換素子に関する。さらに詳しく言え
ば、薄膜光電変換素子の変換効率等の諸特性の改善に関
する。TECHNICAL FIELD The present invention relates to a thin film photoelectric conversion element. More specifically, it relates to improvement of various characteristics such as conversion efficiency of the thin film photoelectric conversion element.
従来の技術 光電変換素子はその用途から、光エネルギーを電気エネ
ルギーに変換するエネルギー変換素子と光情報を電気情
報に変換する情報変換素子に大別することができる。2. Description of the Related Art Photoelectric conversion elements can be roughly divided into energy conversion elements that convert light energy into electric energy and information conversion elements that convert light information into electric information, depending on their applications.
前者のエネルギー変換素子の代表として、光起電力効果
を利用した太陽電池がある。太陽電池は最近のエネルギ
ー事情に照して、今後の新エネルギー源として期待さ
れ、広範な研究、開発が行なわれており、すでに一部で
は実用化されている。この太陽電池を始めとするエネル
ギー変換素子の開発、研究に係る今後の課題は、低価格
化とエネルギー変換効率の大幅な改善にあるものと思わ
れる。A solar cell that utilizes the photovoltaic effect is a typical example of the former energy conversion element. In view of the recent energy situation, solar cells are expected to be new energy sources in the future, extensive research and development have been conducted, and some have already been put to practical use. Future issues related to the development and research of this solar cell and other energy conversion elements are considered to be cost reduction and significant improvement in energy conversion efficiency.
一方、情報変換素子としては光起電力効果を利用したフ
ォトダイオードおよびフォトトランジスタや光導電効果
を利用した光導電セルなどがある。これらの情報変換素
子は近年の光通信技術の発光に伴って各種のものが開発
され実用化されているが、今後の情報変換素子の研究動
向の１つとして集積化がある。すなわち、同一基板上に
情報変換素子と電気素子あるいは他の光素子とを形成し
て情報の高速処理を可能とするものである。On the other hand, examples of the information conversion element include a photodiode and a phototransistor utilizing the photovoltaic effect, and a photoconductive cell utilizing the photoconductive effect. Various types of information conversion elements have been developed and put into practical use in accordance with the light emission of the optical communication technology in recent years, and integration is one of the research trends of information conversion elements in the future. That is, an information conversion element and an electric element or another optical element are formed on the same substrate to enable high-speed processing of information.
このような情況の下で、最近エネルギー変換素子の低価
格化あるいは情報変換素子の集積化を目的としてこれら
光電変換素子の薄膜化が注目されている。光電変換素子
を薄膜で構成すれば、素子の集積化が可能になるばかり
でなく、高価な半導体材料が節約され、また量産に適し
た薄膜形成法を用いることができるので製造コストの低
減が実現される。Under such circumstances, attention has recently been paid to thinning these photoelectric conversion elements for the purpose of cost reduction of energy conversion elements or integration of information conversion elements. If the photoelectric conversion element is composed of a thin film, not only can the element be integrated, but also expensive semiconductor materials can be saved, and the manufacturing cost can be reduced because a thin film forming method suitable for mass production can be used. To be done.
しかしながら、薄膜化により光電変換素子の低価格化お
よび集積化の問題は解決されるものの、光電変換効率等
の特性の点ではまだ不十分であり、さらに改善すべき余
地が多分に残されている。However, although the problems of cost reduction and integration of the photoelectric conversion element are solved by thinning the film, the characteristics such as photoelectric conversion efficiency are still insufficient, and there is still plenty of room for improvement. .
光起電力効果による、光エネルギーの電気エネルギーへ
の変換は、まず光電変換素子に入射した光が半導体活性
領域に吸収され、そこで電子と正孔とを形成し、かくし
て発生した電子と正孔とが素子の内部電界によって分離
されることに基づく。これを光電流あるいは光電位とし
て外部に取出し、動力源等として利用することができ
る。この内部電界は各種手段によって実現することがで
き、例えばpin型接合、ショットキー障壁などがよく知
られている。The conversion of light energy into electric energy by the photovoltaic effect is performed by first absorbing the light incident on the photoelectric conversion element in the semiconductor active region, forming electrons and holes there, and thus generating electrons and holes. Are separated by the internal electric field of the device. This can be taken out as a photocurrent or photopotential and used as a power source or the like. This internal electric field can be realized by various means, and for example, a pin junction, a Schottky barrier, etc. are well known.
一方、光導電効果においては、光電変換素子に入射した
光が半導体に吸収され、この光エネルギーにより形成さ
れた電子と正孔とがキャリヤとなって半導体の電気伝導
度が増加することに基づく。この半導体に外部からバイ
アス電圧を加えることによって、電気的出力を得ること
ができる。On the other hand, the photoconductive effect is based on the fact that the light incident on the photoelectric conversion element is absorbed by the semiconductor, and the electrons and holes formed by this light energy serve as carriers to increase the electrical conductivity of the semiconductor. An electrical output can be obtained by externally applying a bias voltage to this semiconductor.
従って、光起電力効果あるいは光導電効果を利用する光
電変換素子において、半導体領域に吸収される光量が大
きいほど、すなわち光の強さを一定とすれば半導体領域
内への光の浸透深さ（光路長）が長いほど、形成される
電子および正孔の濃度が増して変換効率が向上すること
がわかる。Therefore, in a photoelectric conversion element utilizing the photovoltaic effect or the photoconductive effect, the larger the amount of light absorbed in the semiconductor region, that is, if the intensity of light is constant, the penetration depth of light into the semiconductor region ( It can be seen that the longer the optical path length), the higher the concentration of the formed electrons and holes and the higher the conversion efficiency.
薄膜光電変換素子の従来例１としてアモルファスシリコ
ン（以下、ａ−Siとする）薄膜太陽電池の構成を第５図
に示す。すなわち、平坦なガラス基板11と、その上面に
設けられたSnO2透明電極層12と、透明電極層12の上に設
けられたａ−Si層13と、ａ−Si層13の上に設けられたAl
電極層14から構成されている。ここで、ａ−Si層13はpi
n型接合構造を有しており、透明電極層12の上に順次ｐ
型ａ−Si層、ｉ型ａ−Si層およびｎ型ａ−Si層が積層さ
れている。FIG. 5 shows the structure of an amorphous silicon (hereinafter referred to as a-Si) thin film solar cell as Conventional Example 1 of the thin film photoelectric conversion element. That is, a flat glass substrate 11, a SnO 2 transparent electrode layer 12 provided on the upper surface thereof, an a-Si layer 13 provided on the transparent electrode layer 12, and an a-Si layer 13 provided on the transparent electrode layer 12. Al
It is composed of the electrode layer 14. Here, the a-Si layer 13 is pi
It has an n-type junction structure, and p is sequentially formed on the transparent electrode layer 12.
A type a-Si layer, an i type a-Si layer, and an n type a-Si layer are laminated.
このような構成にして、ガラス基板11側から入射した光
をａ−Si層13に導き、ここで光電変換させて、SnO2透明
電極層12とAl電極層14との間に起電力を生じさせるもの
である。With such a structure, the light incident from the glass substrate 11 side is guided to the a-Si layer 13 and photoelectrically converted there to generate an electromotive force between the SnO 2 transparent electrode layer 12 and the Al electrode layer 14. It is what makes me.
しかしながら、ガラス基板11の表面、ガラス基板11と透
明電極12との界面および透明電極12とａ−Si層13との界
面における入射光の反射が原因となって、ａ−Si層13に
入射される光量が小さくなってしまう。さらに、各層の
界面が平坦かつ平行であるので、例えば光がガラス基板
11に垂直に入射したときには、ａ−Si層13にも同様に垂
直に入射することになり、光はａ−Si層13内を最短距離
を通って通過しようとする。However, due to the reflection of incident light on the surface of the glass substrate 11, the interface between the glass substrate 11 and the transparent electrode 12, and the interface between the transparent electrode 12 and the a-Si layer 13, the light is incident on the a-Si layer 13. The amount of light emitted becomes smaller. Furthermore, since the interfaces of the layers are flat and parallel, for example, light is transmitted through the glass substrate.
When vertically incident on the a-Si layer 13, it also vertically incident on the a-Si layer 13, and the light tries to pass through the a-Si layer 13 through the shortest distance.
その結果、素子の変換効率が低下してしまい、所望の特
性を得ることができなかった。As a result, the conversion efficiency of the device was lowered, and desired characteristics could not be obtained.
そこで、光電変換効率の向上を目的として考案された従
来例２の構成を第６図に示す。この従来例２は第５図の
従来例１において、SnO2透明電極層12の表面に微細な凹
凸を形成し、その上にａ−Si層13を設けるものである。
SnO2透明電極層12は例えばCVD法により形成することが
できるが、表面の微細な凹凸は、CVD反応時の温度ある
いは圧力等の設定条件の変更によって形成される。この
微細な凹凸が設けられたことにより、ガラス基板11から
透明電極層12に入射した光は、透明電極層12とａ−Si層
13との界面で不規則な方向に屈折あるいは回折してａ−
Si層13内に浸透する。従って、ガラス基板11に垂直に入
射した光の大部分がａ−Si層13内では斜めに進行するの
で、ａ−Si層13内における光路長が長くなり、この結果
光電変換効率が向上する。Therefore, FIG. 6 shows the configuration of Conventional Example 2 devised for the purpose of improving the photoelectric conversion efficiency. This conventional example 2 is the same as the conventional example 1 shown in FIG. 5, except that fine irregularities are formed on the surface of the SnO 2 transparent electrode layer 12, and the a-Si layer 13 is provided thereon.
The SnO 2 transparent electrode layer 12 can be formed by, for example, a CVD method, but fine irregularities on the surface are formed by changing setting conditions such as temperature or pressure during the CVD reaction. Due to the provision of the fine irregularities, the light incident on the transparent electrode layer 12 from the glass substrate 11 can be transmitted through the transparent electrode layer 12 and the a-Si layer.
Refraction or diffraction in an irregular direction at the interface with 13
It penetrates into the Si layer 13. Therefore, most of the light vertically incident on the glass substrate 11 travels obliquely in the a-Si layer 13, so that the optical path length in the a-Si layer 13 becomes long, and as a result, the photoelectric conversion efficiency is improved.
しかしながら、一般に透過性をよくするために透明電極
層12の厚さは数μｍ以下に設定され非常に薄いので、こ
の透明電極層12に規則性のある所望の凹凸を形成するこ
とは現在の技術では困難である。従って、形成された凹
凸状態が不均一となり、ａ−Si層13内における光路長の
長大化が十分にはなされないとともに、この凹凸のある
透明電極層12の上に形成されるａ−Si層13の膜厚が不均
一となるので透明電極層12とAl電極層14との間のシャン
ト抵抗が小さくなるなど、素子の特性劣化の原因が生じ
てしまう。However, in general, the thickness of the transparent electrode layer 12 is set to several μm or less so as to improve the transparency, and it is very thin. Therefore, it is a current technique to form desired irregularities having regularity on the transparent electrode layer 12. Is difficult. Therefore, the unevenness formed is not uniform, the optical path length in the a-Si layer 13 is not sufficiently increased, and the a-Si layer formed on the uneven transparent electrode layer 12 is Since the film thickness of 13 becomes non-uniform, the shunt resistance between the transparent electrode layer 12 and the Al electrode layer 14 becomes small, which causes deterioration of the device characteristics.
このようにして作製された第５図および第６図のような
構成の従来例１、２に係る太陽電池の諸特性を以下の第
１表に示す。ただし、従来例２は厚さ１μｍの透明電極
層12の表面に約0.1μｍの凹凸を設けたものである。Table 1 below shows various characteristics of the solar cells according to the conventional examples 1 and 2 having the configurations as shown in FIGS. 5 and 6 thus produced. However, in Conventional Example 2, the surface of the transparent electrode layer 12 having a thickness of 1 μm is provided with irregularities of about 0.1 μm.
第１表に示されるように、透明電極層12の表面に微細な
凹凸を形成した従来例２の諸特性は従来例１よりもわず
かに変換効率が大きいものの、まだ不十分なものであっ
た。 As shown in Table 1, the characteristics of Conventional Example 2 in which fine irregularities are formed on the surface of the transparent electrode layer 12 have slightly higher conversion efficiency than that of Conventional Example 1, but are still insufficient. .
また、これら従来例の他、反射損失を減少させるために
反射防止膜などを設ける方法法もあるが、反射防止膜で
は特定の波長域の光にしか有効でないので、十分な特性
を得ることはできなかった。In addition to these conventional examples, there is also a method of providing an antireflection film or the like in order to reduce reflection loss, but since the antireflection film is effective only for light in a specific wavelength range, sufficient characteristics cannot be obtained. could not.
発明が解決しようとする問題点 以上述べたように、太陽電池その他の光電変換素子にお
いて、薄膜化することにより低価格化および集積化の問
題は解決されつつある。しかしながら、変換効率等の諸
特性は依然として不十分であり、さらに一層の改善が望
まれている。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, in photovoltaic cells and other photoelectric conversion elements, the problems of cost reduction and integration are being solved by thinning them. However, various characteristics such as conversion efficiency are still insufficient, and further improvement is desired.
そこで、本発明の目的は、変換効率など諸特性の優れた
薄膜光電変換素子を提供することにある。Therefore, an object of the present invention is to provide a thin film photoelectric conversion element having excellent characteristics such as conversion efficiency.
問題点を解決するための手段 本発明者は、変換効率等各種特性の優れた薄膜光電変換
素子を開発すべく種々検討、研究した結果、基板表面に
規則的な凹凸を設け、その上に一定膜厚の電極層や半導
体層を形成して光電変換素子を構成することが有効であ
ることを見出した。Means for Solving the Problems The present inventor has conducted various studies and researches in order to develop a thin film photoelectric conversion element excellent in various characteristics such as conversion efficiency. It has been found that it is effective to form a photoelectric conversion element by forming an electrode layer or a semiconductor layer having a film thickness.
すなわち、本発明の薄膜光電変換素子は、表面が凹凸形
状をなしている基板と、該基板表面上に形成され、半導
体層と該半導体層をはさむ透明電極層および電極層から
なる多層薄膜とを有することを特徴とする。That is, the thin-film photoelectric conversion device of the present invention comprises a substrate having a surface having an uneven shape, and a multilayer thin film formed on the surface of the substrate, comprising a semiconductor layer and a transparent electrode layer sandwiching the semiconductor layer and an electrode layer. It is characterized by having.
また、本発明の好ましい態様においては、基板がガラス
からなっており、第１図にこの態様における本発明の薄
膜光電変換素子の断面図を示す。以下、この断面図に沿
って説明する。Further, in a preferred embodiment of the present invention, the substrate is made of glass, and FIG. 1 shows a sectional view of the thin film photoelectric conversion element of the present invention in this embodiment. Hereinafter, description will be given along this sectional view.
まず、ガラス基板１の表面に所望の大きさの凹凸を形成
する。形成方法としては、 （１） 表面状態調節用のロールとして円筒面上に凹凸
が設けられたロールを用意し、ガラス基板製造時にガラ
ス軟化温度域のガラス基板の表面をこのロールで押付け
ることにより表面加工を施す。First, unevenness of a desired size is formed on the surface of the glass substrate 1. As the forming method, (1) prepare a roll having irregularities on the cylindrical surface as a roll for adjusting the surface condition, and press the surface of the glass substrate in the glass softening temperature range with this roll when manufacturing the glass substrate. Surface treatment is applied.
（２） 平坦な表面を有するガラス基板を製造した後、
該表面をエッチングすることにより粗面化する。なお、
エッチングの方式としては、HF、HF＋NH4F、HF＋HNO3等
をエッチング液としたウェットエッチング法やHF、CHF3
等をエッチングガスとしたプラズマエッチング法の他、
スパッタエッチング法あるいはイオンビームエッチング
法を用いることができる。(2) After manufacturing a glass substrate having a flat surface,
The surface is roughened by etching. In addition,
As the etching method, a wet etching method using HF, HF + NH 4 F, HF + HNO 3 etc. as an etching solution or HF, CHF 3
In addition to the plasma etching method using etching gas such as
A sputter etching method or an ion beam etching method can be used.
（３） 平坦な表面を有するガラス基板を製造した後、
該表面に切削および研摩などの機械加工を施す。などが
あり、さらに以上のようにして凹凸を形成した後、ガラ
ス基板１の表面形状の安定化およびガラス表面の結晶性
の回復を目的として熱処理を施してもよい。(3) After manufacturing a glass substrate having a flat surface,
The surface is subjected to machining such as cutting and polishing. For example, after the unevenness is formed as described above, heat treatment may be performed for the purpose of stabilizing the surface shape of the glass substrate 1 and recovering the crystallinity of the glass surface.
ガラス基板１の上に形成される透明電極層２の材料とし
ては、透明度および導電性に優れたSnO2やITOが適して
おり、CVD法あるいは蒸着法等により膜厚0.01〜５μｍ
程度で形成する。As a material for the transparent electrode layer 2 formed on the glass substrate 1, SnO 2 or ITO having excellent transparency and conductivity is suitable, and the film thickness is 0.01 to 5 μm by the CVD method or the vapor deposition method.
Form with a degree.
また、光電変換が行なわれる半導体層３としては、光吸
収係数の大きいａ−Si、GaAsを始めとするIII−Ｖ族化
合物半導体およびII−VI族化合物半導体を用いることが
でき、例えばａ−Siの場合には膜厚0.5〜１μｍ程度、G
aAsの場合には膜厚１〜２μｍ程度、プラズマCVD法、ス
パッタ法あるいは蒸着法等により形成する。なお、太陽
電池等の光起電力素子を構成する場合には、この半導体
層３内にpn接合、pin接合あるいはヘテロ接合を形成す
る必要がある。As the semiconductor layer 3 for photoelectric conversion, III-V group compound semiconductors and II-VI group compound semiconductors such as a-Si and GaAs having a large light absorption coefficient can be used. For example, a-Si In the case of, the film thickness is about 0.5 to 1 μm, G
In the case of aAs, a film thickness of about 1 to 2 μm is formed by a plasma CVD method, a sputtering method, an evaporation method, or the like. When a photovoltaic element such as a solar cell is formed, it is necessary to form a pn junction, a pin junction or a hetero junction in this semiconductor layer 3.
最上層となる電極層４には、反射率が大きく、かつ良導
性の金属材料が適しており、特にAlやAg等を例示でき、
これらは蒸着法、スパッタ法、イオンプレーティング法
あるいはCVD法などにより形成される。For the uppermost electrode layer 4, a metal material having high reflectance and good conductivity is suitable, and Al, Ag, etc. can be exemplified,
These are formed by a vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like.
なお、第１図に示される構成の他、凹凸形状を有する基
板上にショットキー障壁型あるいはMIS型太陽電池を構
成した光起電力素子も本発明の範囲に当然含まれる。In addition to the structure shown in FIG. 1, a photovoltaic element in which a Schottky barrier type or MIS type solar cell is formed on a substrate having an uneven shape is naturally included in the scope of the present invention.
作用 以上のような構成とすることによって、基板上に一定厚
の薄膜を形成するだけで、薄膜の表面は基板表面と同様
の凹凸形状となる。さらに、前述の従来例２において表
面上に凹凸を設けようとした厚さ数μｍ以下の透明電極
層に比べて、基板ははるかに厚いものであるので、この
基板表面に適度な大きさの凹凸を高精度で形成すること
は容易である。従って、基板上に形成された薄膜の表面
を均一性の優れた凹凸形状とすることができる。Operation With the above-described configuration, the surface of the thin film has the same uneven shape as the surface of the substrate only by forming a thin film having a constant thickness on the substrate. Furthermore, since the substrate is much thicker than the transparent electrode layer having a thickness of several μm or less in which the unevenness is to be provided on the surface in the above-mentioned Conventional Example 2, the unevenness of an appropriate size is formed on the surface of the substrate. Is easy to form with high precision. Therefore, the surface of the thin film formed on the substrate can have an uneven shape with excellent uniformity.
例えば、第１図に示す構成とした場合、ガラス基板１の
上に透明電極層２、半導体層３および電極層４を順次そ
れぞれ一定の厚さで積層すれば、各界面は同様の凹凸形
状となる。For example, in the case of the configuration shown in FIG. 1, if the transparent electrode layer 2, the semiconductor layer 3 and the electrode layer 4 are sequentially laminated on the glass substrate 1 with a constant thickness, each interface has a similar uneven shape. Become.
その結果、ガラス基板１を透過し、さらに透明電極層２
から半導体層３に入射する光は、第２図に示されるよう
に、まずＡ点で屈折光と反射光に分波し、さらにこの反
射光はＢ点で再び半導体層３に入射して屈折光を生じ
る。このように、透明電極層２と半導体層３との界面に
おいて、入射光の多重反射屈折げが行なわれるので、こ
の界面での反射光量が減少する。As a result, the glass substrate 1 is transmitted, and the transparent electrode layer 2
As shown in FIG. 2, the light incident on the semiconductor layer 3 is first split into refracted light and reflected light at point A, and this reflected light is again incident on the semiconductor layer 3 at point B and refracted. Produces light. In this way, since multiple reflection refraction of incident light is performed at the interface between the transparent electrode layer 2 and the semiconductor layer 3, the amount of reflected light at this interface is reduced.
同様にして、反射光量の減少はガラス基板１と透明電極
層２との界面においても生じることになる。Similarly, the decrease in the amount of reflected light also occurs at the interface between the glass substrate 1 and the transparent electrode layer 2.
さらに、第２図からわかるように、半導体層３内に浸透
していく屈折光の進行方向は入射光の方向と異なるので
半導体層３内の光路長が長くなる。また電極層４に反射
率の大きい材料を用いているので、半導体層３内で吸収
されなかった光は電極層４との界面で反射されて再び半
導体層３内を通過することになり、一層光路長が長くな
る。Further, as can be seen from FIG. 2, the traveling direction of the refracted light penetrating into the semiconductor layer 3 is different from the incident light direction, so that the optical path length in the semiconductor layer 3 becomes long. Further, since the electrode layer 4 is made of a material having a high reflectance, the light not absorbed in the semiconductor layer 3 is reflected at the interface with the electrode layer 4 and passes through the semiconductor layer 3 again. The optical path length becomes long.
また、均一性の良い凹凸形状のガラス基板１上に各層が
順次形成されるので、半導体層３の膜厚は均一なものと
なる。ここで、ガラス基板１上に形成された凹凸の局部
が鋭い形状になっていても、この上に透明電極層２を堆
積するので透明電極層２の上面は連続的な面となり、こ
の面上に形成される半導体層３は適度な凹凸状態とな
る。従って、従来例２のように透明電極層２と電極層３
との間のシャント抵抗が小さくなることはない。In addition, since each layer is sequentially formed on the glass substrate 1 having an uneven shape with good uniformity, the film thickness of the semiconductor layer 3 becomes uniform. Here, even if the uneven portion formed on the glass substrate 1 has a sharp shape, since the transparent electrode layer 2 is deposited on this, the upper surface of the transparent electrode layer 2 becomes a continuous surface. The semiconductor layer 3 formed in this state has an appropriate unevenness. Therefore, as in Conventional Example 2, the transparent electrode layer 2 and the electrode layer 3 are
The shunt resistance between and does not decrease.
かくして、本発明の薄膜光電変換素子は変換効率が非常
に高いものとなる。すなわち、光導電素子においては明
時の抵抗値と暗時の抵抗値との差が大きく、また光起電
力素子においては生じる電力が大きくなる。さらに、反
射防止膜による反射光量の減少と異なり、本発明では広
範囲にわたる波長域の光に対して反射損失の減少化が達
成される。Thus, the thin film photoelectric conversion element of the present invention has a very high conversion efficiency. That is, in the photoconductive element, the difference between the resistance value at the time of light and the resistance value at the time of darkness is large, and the power generated in the photovoltaic element is large. Further, unlike the reduction of the amount of light reflected by the antireflection film, the present invention achieves reduction of reflection loss for light in a wide wavelength range.
実施例 以下、本発明の実施例について添付図面を参照して説明
する。ただし、本発明は以下の実施例により何等制限さ
れない。Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the following examples.
実施例１ 第１図に示す構成の太陽電池を製作した。Example 1 A solar cell having the structure shown in FIG. 1 was manufactured.
まず、ガラス基板１の製造時に表面状態調整用ロールを
通すことにより、ガラス基板１の表面に第３図に示すよ
うなピッチ0.5mm、高さ0.22mm、開口角90゜および凹
部、凸部の曲率半径35μｍの凹凸を形成した。次に、ガ
ラス基板１の凹凸面上にCVD法によってSnO2透明電極層
２を厚さ１μｍ堆積した。さらに、透明電極層２の上に
ｐ型ａ−Si層、ｉ型ａ−Si層およびｎ型ａ−Si層を順次
プラズマCVD法により形成して、これをａ−Si層３とす
る。なお、このプラマズマCVD法の条件を以下の第２表
に示す。First, when the glass substrate 1 is manufactured, it is passed through a roll for adjusting the surface condition, so that the surface of the glass substrate 1 has a pitch of 0.5 mm, a height of 0.22 mm, an opening angle of 90 ° and concave and convex portions. Asperities having a radius of curvature of 35 μm were formed. Next, the SnO 2 transparent electrode layer 2 was deposited on the uneven surface of the glass substrate 1 by the CVD method to a thickness of 1 μm. Further, a p-type a-Si layer, an i-type a-Si layer and an n-type a-Si layer are sequentially formed on the transparent electrode layer 2 by a plasma CVD method, and this is used as an a-Si layer 3. The conditions of this plasma CVD method are shown in Table 2 below.
次に、ａ−Si層３上にAl電極層４を蒸着法により厚さ0.
5μｍ形成した。 Next, the Al electrode layer 4 is formed on the a-Si layer 3 by vapor deposition to a thickness of 0.
5 μm was formed.
実施例２ ガラス基板１表面上の凹凸形状を第４図のように設定し
た他は実施例１と全く同様の太陽電池を製作した。すな
わち、ピッチ0.5mm、高さ0.36mm、開口角60゜および凹
部、凸部の曲率半径35μｍの凹凸をガラス基板製造時に
表面状態調整用ロールを通すことにより形成したもので
ある。Example 2 A solar cell exactly the same as that of Example 1 was manufactured except that the uneven shape on the surface of the glass substrate 1 was set as shown in FIG. That is, irregularities having a pitch of 0.5 mm, a height of 0.36 mm, an opening angle of 60 ° and concave and convex radii of curvature of 35 μm are formed by passing a surface condition adjusting roll during the production of a glass substrate.
このようにして作製した実施例１および２の太陽電池に
ついて各種特性を調べたところ、次の第３表に示すよう
な結果が得られた。When the various characteristics of the solar cells of Examples 1 and 2 thus manufactured were examined, the results shown in Table 3 below were obtained.
従来の太陽電池の同様な特性はすでに第１表に記載し
た。これらの結果の比較から、本発明による太陽電池は
非常に優れた特性を有することがわかる。 Similar characteristics of conventional solar cells have already been listed in Table 1. From the comparison of these results, it can be seen that the solar cell according to the present invention has very excellent characteristics.
なお、上記の実施例１、２では太陽電池を構成したが、
その他の光起電力素子あるいは光導電素子を構成しても
同様に優れた特性を示すことは言うまでもない。Although the solar cells were constructed in the above-mentioned Examples 1 and 2,
It is needless to say that other photovoltaic elements or photoconductive elements also exhibit excellent characteristics.
発明の効果 以上詳しく述べたように、本発明によれば、基板表面上
に設けられた凹凸が光電変換の反射損失を減少させると
ともに、半導体層等の薄膜中での光路長を長大化する。
従って、幅広い波長域において変換効率が著しく向上す
る等、光電変換の各種特性が優れたものとなる。EFFECTS OF THE INVENTION As described in detail above, according to the present invention, the unevenness provided on the substrate surface reduces the reflection loss of photoelectric conversion and lengthens the optical path length in a thin film such as a semiconductor layer.
Therefore, various characteristics of photoelectric conversion become excellent, such as a marked improvement in conversion efficiency in a wide wavelength range.
かくして、本発明による薄膜光電変換素子は太陽電池、
光センサ、光導電セル等として用いるのに極めて適した
ものとなる。Thus, the thin film photoelectric conversion element according to the present invention is a solar cell,
It is extremely suitable for use as an optical sensor, a photoconductive cell, or the like.
第１図は本発明薄膜光電変換素子の一構成例を示す断面
図、 第２図は凹凸面による多重反射屈折を示す説明図、 第３図および第４図はそれぞれ本発明の実施例１および
２におけるガラス基板１上の凹凸形状を示す断面図、 第５図および第６図はそれぞれ従来例の構成を示す断面
図である。 （主な参照番号） １、11……ガラス基板、２、12……透明電極層、 ３……半導体層、４……電極層、 13……ａ−Si層、14……Al電極層FIG. 1 is a cross-sectional view showing one structural example of the thin film photoelectric conversion element of the present invention, FIG. 2 is an explanatory view showing multiple reflection and refraction by an uneven surface, and FIGS. 3 and 4 are Embodiment 1 of the present invention and 2 is a sectional view showing the concavo-convex shape on the glass substrate 1 in FIG. 2, and FIGS. 5 and 6 are sectional views showing the configuration of the conventional example. (Main reference numbers) 1, 11 ... Glass substrate, 2, 12 ... Transparent electrode layer, 3 ... Semiconductor layer, 4 ... Electrode layer, 13 ... a-Si layer, 14 ... Al electrode layer
Claims (6)
板表面上に形成され、半導体層と該半導体層をはさむ透
明電極層および電極層からなる多層薄膜とを有する薄膜
光電変換素子において、上記透明電極層の膜厚が0.01〜
５μｍであり、該半導体層の膜厚が0.5〜２μｍであ
り、かつ基板表面の凹凸のピッチが約0.5mmでかつ凹凸
の高さが0.22mmないし0.36mmであることを特徴とする薄
膜光電変換素子。1. A thin film photoelectric conversion element comprising a substrate having a surface with an uneven shape, and a semiconductor layer formed on the surface of the substrate, a semiconductor layer, and a multilayer thin film including a transparent electrode layer and an electrode layer sandwiching the semiconductor layer. , The thickness of the transparent electrode layer is 0.01 ~
5 μm, the thickness of the semiconductor layer is 0.5 to 2 μm, the pitch of the irregularities on the substrate surface is about 0.5 mm, and the height of the irregularities is 0.22 mm to 0.36 mm. element.
テロ接合のうちいずれかを有していることを特徴とする
特許請求の範囲第１項記載の薄膜光電変換素子。2. The thin-film photoelectric conversion element according to claim 1, wherein the semiconductor layer has any one of a pn junction, a pin junction and a hetero junction.
る特許請求の範囲第１項又は第２項に記載の薄膜光電変
換素子。3. The thin film photoelectric conversion device according to claim 1, wherein the substrate is made of glass.
成されることを特徴とする特許請求の範囲第３項に記載
の薄膜光電変換素子。4. The thin film photoelectric conversion element according to claim 3, wherein the uneven shape of the substrate is formed by roll molding.
成されることを特徴とする特許請求の範囲第３項に記載
の薄膜光電変換素子。5. The thin film photoelectric conversion element according to claim 3, wherein the uneven shape of the substrate is formed by etching.
されることを特徴とする特許請求の範囲第３項に記載の
薄膜光電変換素子。6. The thin film photoelectric conversion element according to claim 3, wherein the uneven shape of the substrate is formed by machining.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60119854A JPH0750793B2 (en) | 1985-06-04 | 1985-06-04 | Thin film photoelectric conversion element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60119854A JPH0750793B2 (en) | 1985-06-04 | 1985-06-04 | Thin film photoelectric conversion element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61278171A JPS61278171A (en) | 1986-12-09 |
| JPH0750793B2 true JPH0750793B2 (en) | 1995-05-31 |
Family
ID=14771913
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60119854A Expired - Lifetime JPH0750793B2 (en) | 1985-06-04 | 1985-06-04 | Thin film photoelectric conversion element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0750793B2 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2682658B2 (en) * | 1988-09-30 | 1997-11-26 | 鐘淵化学工業株式会社 | Semiconductor device |
| JPH02164077A (en) * | 1988-12-19 | 1990-06-25 | Hitachi Ltd | Amorphous silicon solar cell |
| JPH073879B2 (en) * | 1990-01-31 | 1995-01-18 | 株式会社日立製作所 | Solar cell |
| DE4201126A1 (en) * | 1992-01-17 | 1992-06-11 | Gerhard Dr Ing Schumm | Semiconductor thin film component for photoelectric energy conversion - has sawtooth formation of active layer on rear face for multiple internal reflection of unabsorbed light |
| JP2002261302A (en) * | 2001-02-28 | 2002-09-13 | Kyocera Corp | THIN-FILM CRYSTALLINE Si SOLAR CELL |
| EP1950813A4 (en) * | 2005-11-17 | 2010-07-21 | Asahi Glass Co Ltd | Transparent conductive substrate for solar cell and process for producing the same |
| US8012317B2 (en) | 2006-11-02 | 2011-09-06 | Guardian Industries Corp. | Front electrode including transparent conductive coating on patterned glass substrate for use in photovoltaic device and method of making same |
| US8334452B2 (en) | 2007-01-08 | 2012-12-18 | Guardian Industries Corp. | Zinc oxide based front electrode doped with yttrium for use in photovoltaic device or the like |
| WO2010044269A1 (en) * | 2008-10-17 | 2010-04-22 | 株式会社アルバック | Manufacturing method for solar cell |
| IT1399376B1 (en) * | 2010-04-12 | 2013-04-16 | Milano Politecnico | PHOTOVOLTAIC CELL, IN PARTICULAR FOR INTEGRATED ARCHITECTURAL APPLICATIONS, AND METHOD OF MANUFACTURE OF THAT CELL. |
| CN111446372A (en) * | 2020-03-20 | 2020-07-24 | 杭州电子科技大学 | Wavy ITO transparent electrode and organic solar cell |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59152672A (en) * | 1983-02-19 | 1984-08-31 | Semiconductor Energy Lab Co Ltd | Photoelectric converter |
| JPS59152676A (en) * | 1983-02-21 | 1984-08-31 | Sumitomo Electric Ind Ltd | Amorphous silicon photovoltaic element |
| JPS59127880A (en) * | 1983-11-10 | 1984-07-23 | Semiconductor Energy Lab Co Ltd | Photoelectric conversion device and manufacture thereof |
-
1985
- 1985-06-04 JP JP60119854A patent/JPH0750793B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61278171A (en) | 1986-12-09 |
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