JPS623595B2 - - Google Patents
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- Publication number
- JPS623595B2 JPS623595B2 JP52085973A JP8597377A JPS623595B2 JP S623595 B2 JPS623595 B2 JP S623595B2 JP 52085973 A JP52085973 A JP 52085973A JP 8597377 A JP8597377 A JP 8597377A JP S623595 B2 JPS623595 B2 JP S623595B2
- Authority
- JP
- Japan
- Prior art keywords
- photoelectric conversion
- thin film
- conversion device
- pzt
- light
- 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
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- 238000006243 chemical reaction Methods 0.000 claims description 43
- 239000010409 thin film Substances 0.000 claims description 41
- 229910052782 aluminium Inorganic materials 0.000 claims description 15
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 15
- 239000002184 metal Substances 0.000 claims description 15
- 229910001220 stainless steel Inorganic materials 0.000 claims description 10
- 239000010935 stainless steel Substances 0.000 claims description 10
- 239000013078 crystal Substances 0.000 claims description 4
- 239000006104 solid solution Substances 0.000 claims description 3
- 238000007740 vapor deposition Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 description 12
- 230000000694 effects Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 239000000758 substrate Substances 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000000704 physical effect Effects 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 229910052573 porcelain Inorganic materials 0.000 description 4
- 230000002269 spontaneous effect Effects 0.000 description 4
- 239000003989 dielectric material Substances 0.000 description 3
- 239000013590 bulk material Substances 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 230000005621 ferroelectricity Effects 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 229910020698 PbZrO3 Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000002800 charge carrier Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009770 conventional sintering Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- NKZSPGSOXYXWQA-UHFFFAOYSA-N dioxido(oxo)titanium;lead(2+) Chemical compound [Pb+2].[O-][Ti]([O-])=O NKZSPGSOXYXWQA-UHFFFAOYSA-N 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- -1 tungsten bronze type compound Chemical class 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Landscapes
- Photovoltaic Devices (AREA)
Description
【発明の詳細な説明】
本発明は光電変換装置に関するものであり、さ
らに詳しく述べるならば強誘電体を用いた光電変
換装置に関するものである。
ｐ−ｎ又はｐ−ｎ−ｐ導電型半導体の接合、又
は半導体と金属の接合を使用した光電変換装置が
広く使用されていることは周知である。これらの
光電変換装置は入射光により自ら起電力を発生す
るので外部電源は必要ない。強誘電体について
は、SbSIが光電効果をもつことは周知である
が、光電流を流すためには外部電源を必要とす
る。
Applied Physics Letters，Vol.29，No.８，15
October 1976，第491及び492頁に発表された強
誘電体薄膜の物性の研究によると強誘電体が光電
変換することはあり得ないという、広く流布しま
た確立している認識に何らの修正も加えられてお
らず、該研究においても光電変換の試験はなされ
ておらない。
本発明者は酸化物強誘電体薄膜の研究を行つた
過程で強誘電体の光電変換現象を発見し、また
PbTiO3，PbZrO3の固溶体又は混晶体からなり、
真空中で形成された酸化物強誘電体薄膜の表面に
金属導電層を配置してなる光電変換装置を発明す
るに至つた。この光電変換装置によると酸化物強
誘電体薄膜に入射した光は該薄膜内で電流に変換
され、金属導電層を経て該装置の外部に取出され
る。強誘電体が薄膜でなくバルクであるかあるい
は強誘電性を示さないと、光電変換は起こらな
い。この原因は理論的に解明されるに至つていな
いが、強誘電体が薄膜化されることによる自発分
極Psの変化と関連があると推察される。
酸化物強誘電体は、PbTiO3及びPbZrO3が固溶
体又は混晶を生成する組成範囲に選定された量の
PbTiO3（チタン酸鉛）及びPbZrO3（ジルコン酸
鉛）を主成分とする。
この組成には、基本成分として、PbZrO3と
PbTiO3の２成分の基本組成と、基本組成を変成
した組成及び微量添加物を加えた組成がこれに含
まれる。すなわち、本発明の組成は次式，，
で示される。
xPbZrO3−yPbTiO3
但しｘ＋ｙ＝１（但しｘ≧0.2）
xPbZrO3−yPbTiO3
−zPb（B1B2）O3
但しｘ＋ｙ＋ｚ＝１（但しｘ≧0.2）
ここでB1，B2は、全体の原子価がプラスの４
価となるような組合せの元素名である。たとえば
B1，B2がそれぞれ２価のCoが1/3モル、５価の
Nbが2/3モルであると全体の原子価は４価にな
る。
xPbZrO3−yPbTiO3
−ｚ1/2（Pb2B2O7又はPb2B2O6）
ここで、Ｂは原子価が５価の元素、すなわち
Ta，Nb，Sbの少なくとも１元素を含み、同時に
Pbも含む成分の略号、ｘ＋ｙ＋ｚ＝１（但しｘ
≧0.2）であり、Pb2B2O7はPbを含むパイロクロ
ア形化合物の一般式であり、さらにPb2B2O6は同
様に鉛（Pb）を含むタングステンブロンズ形化
合物の一般式である。
上記〜で組成が表わされる結晶のPbを
Ba，Sr又はCaの２価金属で一部又は全部置換し
た組成においても、Ba等はPbと同様の作用を奏
する。
なお上記、，，の組成に強誘電特性を改
善するための微量成分を添加した組成も本発明の
強誘電体薄膜に使用することができる。
導電金属層は光電変換された電荷の担体を外部
に取出すものであつて、アルミニウム、ステンレ
ス鋼などの各種金属が使用される。
強誘電体に関し、薄膜とは薄膜技術における一
般的意味を有しており、例えば、抵抗加熱、外熱
るつぼ、熱放射加熱、高周波加熱、電子衝撃、電
子ビームなどの各種加熱手段を利用した蒸着法又
はスパツタリング法などでの真空中で成膜される
ものであつて、バルク、磁器（セラミツク）とは
異なる。先に述べたようにバルクと酸化物強誘電
体薄膜との物性の差異によつて光電変換効果の発
生有無が生じる。よつて、酸化物強誘電体薄膜形
成の条件、例えばその付着速度、などを適宜調節
すると光電変換効果が高められるであろう。酸化
物強誘電体薄膜の厚さは、強誘電性が失なわれな
い厚さであれば、どのような厚さであつてもよい
が、一般には数ミクロン〜30μｍが良好である。
本発明の光電変換装置は可視光線に最も高感度
で感応する。また本発明の光電変換装置はある入
射光パワーまでは入射光パワーに対する出力電圧
の関係がほぼ完全な直線関係を呈する。さらに、
光電変換効率が従来の光電変換装置、例えば熱電
対、に対して100倍も優れている。
本発明の光電変換装置は、従来のホトダイオー
ド、ホトトランジスタなどが使用されるあらゆる
分野で使用可能であり、入出力の直線性が要求さ
れる光センサ又は、高い変換率が要求されるレー
ザーのパワーメーターとして極めて優れている。
以下、本発明の実施例及び比較例を説明する。
以下の実施例において酸化物強誘電体薄膜を次
の方法で製作した。PZTの名称で周知のPbTiO3
及びPbZrO3の固溶体を直径８mm厚さ８mmのター
ゲツトとして、エレクトロンビーム蒸着法で厚さ
300μｍのステンレス鋼基板上に、薄膜を成長さ
せた。エレクトロンビーム蒸着装置内の圧力約
10-5Torr、ステンレス鋼板基板の温度250〜400
℃にして蒸着を行つた。薄膜の成長速度は約0.5
μｍ／分であつた。得られた薄膜をPbOを含むる
つぼの中で500〜800℃で数時間熱処理し、薄膜の
Ｘ線回析パターンを調べたところ、ほぼ等モルの
PbTiO3のPbZrO3の組成（以下、PZTと略記す
る）を有する薄膜であることが確認された。なお
最良の熱処理温度は650℃であつた。
10〜20μｍの厚さに成長したPZT薄膜の自発分
極（Ps）及び抗電界（Ec）はそれぞれ4.2μＣ／
cm2及び5.5KV／cmであつた。なお、エレクトロン
ビームのターゲツトとして使用したPZT磁器の自
発分極（Ps）及び抗電界（Pc）はそれぞれ30μ
Ｃ／cm2及び13KV／cmであつた。
実施例 １
厚さ10μｍであり且つ面積が10mm×10mmのPZT
薄膜１の上に厚さ0.5μｍのアルミニウム層３を
真空蒸着により第１図に示すように被着した。ア
ルミニウム層３とステンレス鋼基板２を導線を介
して直流電圧計４により接続した。第１図に示す
構造を有する光電変換装置１０の上方から矢印５
で示された太陽光線（薄日）を、常温で、アルミ
ニウム層３の全面及びPZT薄膜１のアルミニウム
層３外に表出された面１ａの殆んどに、入射した
ところ、直流電圧計４によつて入射側をマイナス
とする、220ｍＶの起電力が発生したことが確認
された。
実施例 ２
実施例１の光電変換装置１０を使用し波長が
5145Å（緑色光）、4880Å（青色光）、及び4579Å
（青色光）の３種のレーザー光をアルミニウム層
３の表面積当りのパワーを70μＷ／cm2まで変化さ
せて入射した。負荷抵抗をなしで、PZT薄膜１の
単位面積当りの開放電圧（μＶ／cm2）のレーザー
パワーに対する関係を第２図に示す。出力電圧の
極性は入射側がマイナスであつた。
この関係から、レーザーパワーに対して出力電
圧が完全な直線関係を有していることが分かる。
入射レーザー光線が5145Å，4880Å，及び4579Å
の場合は直線の勾配はそれぞれ18，14及び70μ
Ｖ／μＷである。70μＷ／cm2までのレーザーパワ
ーでは各波長に対して直線関係が維持されてい
た。この実施例から、PZT薄膜１の面積にほぼ等
しいようにレーザービーム束を拡大して、光電変
換を実施し得ることが分かる。
実施例 ３
実施例１の光電変換装置１０の直流電圧計４と
並列に外部抵抗（図示せず）を接続し、実施例１
と同様にレーザー光の入射を行つた。この外部抵
抗の抵抗値を1KΩから10KΩまで変化させて、
抵抗器を流れる電流（極性は入射側がマイナス）
及び抵抗器で消費される電力を測定した。この結
果を第３図に示す。
第３図において外部抵抗が135KΩのところに
出力電力の極大値が見られる。したがつて光電変
換装置の内部抵抗は、135KΩと考えられる。こ
の内部抵抗から、アルミニウム及びステンレス鋼
の抵抗を無視して、PZTの比抵抗を求めると、
PZTの比抵抗ρは、
ρ＝１３５×１０３／１０×１０−４＝1.35×108Ω
−cm
になる。
実施例 ４
実施例１の光電変換装置１０に3500〜6000Åの
波長のレーザー光を実施例１と同様に入射して光
電変換効率を求めた結果を、波長が最大になる
4000Å附近の光電変換効率を1.0とした相対的光
電変換効率を第４図のグラフに示す。
実施例 ５
ステンレス鋼基板２を取外したほかは実施例１
と同様の光電変換装置１０（第５図）を使用し
て、実施例１と同様な条件でレーザー光の入射を
行つた。直流電圧計４により測定された電圧は実
施例１より僅かに低かつたが、レーザー光の入射
により光電変換装置１０内に光入射側をマイナス
とする起電力が発生していることが確認された。
この実施例から、ステンレス鋼基板２は電流を外
部に導通させる役割を担つており、光電変換には
直接関与していないことが、分かる。
実施例 ６
第６図に図示された如く、寸法が６mm×35mmの
ステンレス鋼基板２の上に、順次寸法が５mm×35
mmのPZT薄膜１及び寸法がそれぞれ幅２mm×長さ
10mmであり且つ相互に３mmの間隔（ｈ）で隔てら
れた２枚のアルミニウム薄膜３ａ，３ｂを形成し
光電変換装置１０を、実施例１と同様の方法で製
作した。薄膜１，３及び基板の厚さは実施例１と
同様であつた。アルミニウム薄膜３ａ，３ｂの間
に直流電圧計４を接続した。アルミニウム薄膜３
ａ及びPZT薄膜１の点線の円７で囲まれた部分に
レーザー光を入射したところ、入射側７をマイナ
スとする起動力が直流電圧計４により検出され
た。入射されるアルミニウム薄膜を３ａから３ｂ
に変え、同様にレーザー光を入射したところ入射
側７ｂをマイナスとする逆極性の起電力が検出さ
れた。
この実施例から分かることは次のとおりであ
る。PZT薄膜上１に配置されたアルミニウム薄膜
３ａ，３ｂの間隔（ｈ）が、PZT薄膜１の厚さよ
り極めて大きくても、光の照射により起電力が発
生する。この電流の担体はどのようなものである
にせよ、電流の担体は光が入射されていないアル
ミニウム薄膜３ａ又は３ｂの領域における金属と
誘電物質との境界を通過している。これらの事実
から、この光非入射アルミニウム薄膜はステンレ
ス鋼基板２と同様な機能を有していることが推定
される。
光の入射領域７の相違により起電力の極性が変
化する現象を利用して、各入射領域の光量を比較
することができる。
実施例 ７
実施例２と同様に4880Åのレーザー光をパワー
9.6ｍＶ（17.1ｍＷ／cm2）で入射しつつ光電変換
装置１０の温度を350℃から常温まで低下させ、
起電力を測定した。この測定において焦電効果に
よる起電力が測定値に含まれないように留意して
実験を行つた。この結果を第７図に示す。第７図
から分かるように、PZTのキユリー点（ｘ）320
℃以上では起電力（光入射側がマイナスの極性）
は発生しない。また、250℃以下で温度に対して
直線的に起電力が変化している。これらの事実か
ら、光起電力の発生はPZT薄膜の強誘電体の自発
分極に特有な現象に関連しているであろうと推定
される。起電力と温度の直線関係を利用して光電
変換装置を温度センサーとして使用することがで
きる。
比較例 １
実施例１の光電変換装置１０を300℃程度に加
熱しつつ、レーザー光の照射を行つたところ、電
流は検出されなかつた。この結果からPZTのキユ
リー点以上の温度では光電効果がないことが分か
る。実施例７及び比較例１より、本発明において
は誘電体を強誘電体に限定した。
比較例 ２
常法の焼結法によつてPZT磁器を製作し、この
厚さを30〜40μｍに削つた薄肉磁器を第１図の
PZT薄膜１に代えて配置した第１の如き光電変換
装置１０を製作した。第１図と同じ条件で光を入
射したが焦電効果による起電力は発生するもの
の、光起電力は検出されなかつた。この結果よ
り、本発明では誘電体を薄膜に限定した。焼結法
によつて作られたPZTは、バルク材の物性そのも
のを有し、これを薄くしただけではその物性には
変化がないために、光電効果を有さないと考えら
れる。
実施例 ８
上記，及び式で示される組成について
ｘ，ｙ，ｚを次表のように変化させ、実施例１と
同様の条件で光電変換装置を製作し、光起電力の
発生を確認した。
【表】DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoelectric conversion device, and more specifically, to a photoelectric conversion device using a ferroelectric material. It is well known that photoelectric conversion devices using p-n or p-n-p conductivity type semiconductor junctions or semiconductor-to-metal junctions are widely used. These photoelectric conversion devices generate their own electromotive force using incident light, so they do not require an external power source. Regarding ferroelectric materials, it is well known that SbSI has a photoelectric effect, but it requires an external power source to flow photocurrent. Applied Physics Letters, Vol.29, No.8, 15
A study of the physical properties of ferroelectric thin films, published in October 1976, pages 491 and 492, shows that there is no correction to the widely held and well-established belief that ferroelectrics cannot undergo photoelectric conversion. No photoelectric conversion tests were conducted in this research. The present inventor discovered the photoelectric conversion phenomenon of ferroelectric materials in the process of researching oxide ferroelectric thin films, and also
Consisting of a solid solution or mixed crystal of PbTiO 3 and PbZrO 3 ,
We have now invented a photoelectric conversion device in which a metal conductive layer is disposed on the surface of an oxide ferroelectric thin film formed in vacuum. According to this photoelectric conversion device, light incident on an oxide ferroelectric thin film is converted into an electric current within the thin film, and is extracted to the outside of the device via a metal conductive layer. If the ferroelectric material is not a thin film but a bulk material or does not exhibit ferroelectricity, photoelectric conversion will not occur. Although the cause of this has not yet been theoretically elucidated, it is presumed that it is related to changes in the spontaneous polarization Ps due to the thinning of the ferroelectric material. The oxide ferroelectric material contains PbTiO 3 and PbZrO 3 in amounts selected in a composition range that forms a solid solution or mixed crystal.
Main ingredients are PbTiO 3 (lead titanate) and PbZrO 3 (lead zirconate). This composition contains PbZrO3 and
This includes the two-component basic composition of PbTiO 3 , a modified basic composition, and a composition with trace additives added. That is, the composition of the present invention is expressed by the following formula:
It is indicated by. xPbZrO 3 -yPbTiO 3where x + y = 1 (however x ≧ 0.2 ) The valence of is positive 4
This is the element name of the combination that gives the value. for example
B 1 and B 2 are respectively 1/3 mole of divalent Co and 1/3 mole of pentavalent Co.
When Nb is 2/3 mole, the total valence becomes 4. xPbZrO 3 −yPbTiO 3 −z1/2 (Pb 2 B 2 O 7 or Pb 2 B 2 O 6 ) Here, B is a pentavalent element, i.e.
Contains at least one element of Ta, Nb, and Sb, and at the same time
Abbreviations of components including Pb, x+y+z=1 (however, x
≧0.2), Pb 2 B 2 O 7 is the general formula of a pyrochlore type compound containing Pb, and Pb 2 B 2 O 6 is also the general formula of a tungsten bronze type compound containing lead (Pb). . Pb of the crystal whose composition is represented by ~ above
Even in compositions in which the divalent metals such as Ba, Sr, or Ca are partially or fully substituted, Ba etc. exhibits the same effect as Pb. Note that a composition in which a trace amount of a component to improve the ferroelectric properties is added to the above composition can also be used in the ferroelectric thin film of the present invention. The conductive metal layer is for extracting photoelectrically converted charge carriers to the outside, and various metals such as aluminum and stainless steel are used for the conductive metal layer. Regarding ferroelectrics, thin film has a general meaning in thin film technology, such as vapor deposition using various heating means such as resistance heating, external heating crucible, thermal radiation heating, radio frequency heating, electron impact, and electron beam. It is formed into a film in a vacuum using a sputtering method or a sputtering method, and is different from bulk or porcelain (ceramic). As mentioned above, the occurrence or non-occurrence of the photoelectric conversion effect depends on the difference in physical properties between the bulk and the oxide ferroelectric thin film. Therefore, the photoelectric conversion effect may be enhanced by appropriately adjusting the conditions for forming the oxide ferroelectric thin film, such as its deposition rate. The thickness of the oxide ferroelectric thin film may be any thickness as long as it does not lose its ferroelectricity, but generally a few microns to 30 μm is good. The photoelectric conversion device of the present invention is most sensitive to visible light. Further, in the photoelectric conversion device of the present invention, the relationship between the output voltage and the incident light power exhibits an almost perfectly linear relationship up to a certain incident light power. moreover,
The photoelectric conversion efficiency is 100 times higher than that of conventional photoelectric conversion devices, such as thermocouples. The photoelectric conversion device of the present invention can be used in all fields where conventional photodiodes, phototransistors, etc. are used, and can be used in optical sensors that require input/output linearity or laser power that requires a high conversion rate. Very good as a meter. Examples and comparative examples of the present invention will be described below. In the following examples, oxide ferroelectric thin films were manufactured by the following method. PbTiO 3 , better known as PZT
and PbZrO 3 as a target with a diameter of 8 mm and a thickness of 8 mm.
Thin films were grown on 300 μm stainless steel substrates. Pressure inside electron beam evaporation equipment approx.
10 -5 Torr, stainless steel plate substrate temperature 250~400
Deposition was carried out at ℃. The growth rate of the thin film is approximately 0.5
It was μm/min. The obtained thin film was heat-treated at 500 to 800℃ for several hours in a crucible containing PbO, and the X-ray diffraction pattern of the thin film was examined.
It was confirmed that the film had a composition of PbZrO 3 of PbTiO 3 (hereinafter abbreviated as PZT). The best heat treatment temperature was 650°C. The spontaneous polarization (Ps) and coercive electric field (Ec) of a PZT thin film grown to a thickness of 10 to 20 μm are each 4.2 μC/
cm2 and 5.5KV/cm. The spontaneous polarization (Ps) and coercive electric field (Pc) of the PZT porcelain used as the electron beam target were each 30μ.
C/cm 2 and 13 KV/cm. Example 1 PZT with a thickness of 10 μm and an area of 10 mm x 10 mm
An aluminum layer 3 having a thickness of 0.5 .mu.m was deposited on the thin film 1 by vacuum evaporation as shown in FIG. The aluminum layer 3 and the stainless steel substrate 2 were connected by a DC voltmeter 4 via a conductive wire. Arrow 5 from above the photoelectric conversion device 10 having the structure shown in FIG.
When the sunlight (light sun) shown in is incident on the entire surface of the aluminum layer 3 and most of the surface 1a of the PZT thin film 1 exposed outside the aluminum layer 3 at room temperature, the DC voltmeter 4 shows Therefore, it was confirmed that an electromotive force of 220 mV was generated, with the incident side being negative. Example 2 Using the photoelectric conversion device 10 of Example 1, the wavelength was
5145Å (green light), 4880Å (blue light), and 4579Å
Three types of laser light (blue light) were applied to the aluminum layer 3 while varying the power per surface area of 70 μW/cm 2 . FIG. 2 shows the relationship between the open circuit voltage (μV/cm 2 ) per unit area of the PZT thin film 1 and the laser power without any load resistance. The polarity of the output voltage was negative on the incident side. From this relationship, it can be seen that the output voltage has a perfectly linear relationship with the laser power.
The incident laser beam is 5145Å, 4880Å, and 4579Å
In the case of , the slope of the straight line is 18, 14 and 70μ, respectively.
V/μW. A linear relationship was maintained for each wavelength for laser powers up to 70 μW/cm 2 . From this example, it can be seen that photoelectric conversion can be performed by expanding the laser beam flux so that it is approximately equal to the area of the PZT thin film 1. Example 3 An external resistor (not shown) was connected in parallel with the DC voltmeter 4 of the photoelectric conversion device 10 of Example 1.
Laser light was incident in the same manner as in . By changing the resistance value of this external resistor from 1KΩ to 10KΩ,
Current flowing through the resistor (polarity is negative on the input side)
and the power consumed by the resistor was measured. The results are shown in FIG. In Figure 3, the maximum value of the output power can be seen when the external resistance is 135KΩ. Therefore, the internal resistance of the photoelectric conversion device is considered to be 135KΩ. If we calculate the specific resistance of PZT from this internal resistance, ignoring the resistance of aluminum and stainless steel, the specific resistance ρ of PZT is: ρ=135×10 3 /10×10 −4 = 1.35×10 8 Ω
−cm. Example 4 A laser beam with a wavelength of 3500 to 6000 Å was incident on the photoelectric conversion device 10 of Example 1 in the same manner as in Example 1, and the photoelectric conversion efficiency was determined.
The graph in Figure 4 shows the relative photoelectric conversion efficiency, assuming that the photoelectric conversion efficiency around 4000 Å is 1.0. Example 5 Example 1 except that the stainless steel substrate 2 was removed
Using the same photoelectric conversion device 10 (FIG. 5), laser light was applied under the same conditions as in Example 1. Although the voltage measured by the DC voltmeter 4 was slightly lower than in Example 1, it was confirmed that an electromotive force with a negative value on the light incident side was generated in the photoelectric conversion device 10 due to the incidence of laser light. .
It can be seen from this example that the stainless steel substrate 2 plays the role of conducting current to the outside and is not directly involved in photoelectric conversion. Example 6 As shown in FIG.
mm PZT thin film 1 and dimensions are each 2 mm width x length
A photoelectric conversion device 10 was manufactured in the same manner as in Example 1 by forming two aluminum thin films 3a and 3b having a thickness of 10 mm and separated from each other by a distance (h) of 3 mm. The thicknesses of thin films 1 and 3 and the substrate were the same as in Example 1. A DC voltmeter 4 was connected between the aluminum thin films 3a and 3b. aluminum thin film 3
When a laser beam was incident on a portion of the PZT thin film 1 surrounded by a dotted circle 7, a starting force with a negative value on the incident side 7 was detected by the DC voltmeter 4. The incident aluminum thin film is separated from 3a to 3b.
When a laser beam was similarly applied instead of , an electromotive force of opposite polarity was detected, with the incident side 7b being negative. What can be understood from this example is as follows. Even if the distance (h) between the aluminum thin films 3a and 3b disposed on the PZT thin film 1 is much larger than the thickness of the PZT thin film 1, an electromotive force is generated by light irradiation. Whatever the carrier of this current is, it passes through the boundary between the metal and the dielectric material in the region of the aluminum thin film 3a or 3b where no light is incident. From these facts, it is presumed that this light non-injecting aluminum thin film has the same function as the stainless steel substrate 2. By utilizing the phenomenon that the polarity of the electromotive force changes depending on the difference in the light incident areas 7, it is possible to compare the amount of light in each incident area. Example 7 Same as Example 2, power of 4880 Å laser light
Lowering the temperature of the photoelectric conversion device 10 from 350° C. to room temperature while inputting at 9.6 mV (17.1 mW/cm 2 ),
The electromotive force was measured. In this measurement, care was taken to ensure that the electromotive force due to the pyroelectric effect was not included in the measured value. The results are shown in FIG. As can be seen from Figure 7, the Curie point (x) of PZT is 320
Above ℃, electromotive force (negative polarity on the light incident side)
does not occur. Furthermore, the electromotive force changes linearly with temperature below 250°C. From these facts, it is presumed that the generation of photovoltaic force is related to a phenomenon peculiar to the spontaneous polarization of the ferroelectric material of the PZT thin film. A photoelectric conversion device can be used as a temperature sensor by utilizing the linear relationship between electromotive force and temperature. Comparative Example 1 When the photoelectric conversion device 10 of Example 1 was heated to about 300° C. and irradiated with laser light, no current was detected. This result shows that there is no photoelectric effect at temperatures above the Curie point of PZT. From Example 7 and Comparative Example 1, the dielectric material in the present invention was limited to ferroelectric material. Comparative Example 2 PZT porcelain was produced by a conventional sintering method, and the thin-walled porcelain was shaved to a thickness of 30 to 40 μm as shown in Figure 1.
A first photoelectric conversion device 10 was manufactured in which the PZT thin film 1 was replaced. Light was incident under the same conditions as in FIG. 1, but although an electromotive force was generated due to the pyroelectric effect, no photoelectromotive force was detected. Based on this result, in the present invention, the dielectric material is limited to a thin film. PZT made by the sintering method has the same physical properties as a bulk material, and simply making it thinner does not change its physical properties, so it is thought to have no photoelectric effect. Example 8 A photoelectric conversion device was manufactured under the same conditions as in Example 1, with x, y, and z changed as shown in the following table for the composition shown above and in the formula, and generation of photovoltaic force was confirmed. 【table】
第１図は本発明の一具体例に係る光電変換装置
を示す概念図、第２図は入射光パワーに対する出
力電圧の関係を示すグラフ、第３図は外部抵抗に
対する、この抵抗を流れる電流及び電力の関係を
示すグラフ、第４図は入射光線波長に対する光電
変換感度の関係を示すグラフ、第５図及び第６図
は他の具体例に係る光電変換装置の概念図、第７
図は起電力と温度の関係を示すグラフである。
１……PZT薄膜、２……ステンレス鋼基板、３
……金属層、５……光線、１０……光電変換装
置。
FIG. 1 is a conceptual diagram showing a photoelectric conversion device according to a specific example of the present invention, FIG. 2 is a graph showing the relationship between the output voltage and the incident light power, and FIG. 3 is a graph showing the relationship between the external resistance and the current flowing through this resistance. Graph showing the relationship between power; FIG. 4 is a graph showing the relationship between photoelectric conversion sensitivity and wavelength of incident light; FIGS. 5 and 6 are conceptual diagrams of photoelectric conversion devices according to other specific examples; FIG.
The figure is a graph showing the relationship between electromotive force and temperature. 1...PZT thin film, 2...Stainless steel substrate, 3
...Metal layer, 5...Light beam, 10...Photoelectric conversion device.
Claims (1)
り、真空中で形成された強誘電体薄膜上に金属導
電層を配置してなる光電変換装置。 ２ ステンレス等の金属板に金属導電層を配置し
蒸着により強誘電体薄膜を載置されてなる特許請
求の範囲第１項記載の光電変換装置。 ３ 強誘電体薄膜上の金属導電層はアルミニウム
等の金属を蒸着で形成してなる特許請求の範囲第
１項または第２項記載の光電変換装置。[Scope of Claims] 1. A photoelectric conversion device comprising a solid solution or mixed crystal of PbTiO 3 and PbZrO 3 and a metal conductive layer disposed on a ferroelectric thin film formed in vacuum. 2. The photoelectric conversion device according to claim 1, wherein a metal conductive layer is arranged on a metal plate such as stainless steel, and a ferroelectric thin film is placed on the metal plate by vapor deposition. 3. The photoelectric conversion device according to claim 1 or 2, wherein the metal conductive layer on the ferroelectric thin film is formed by vapor deposition of a metal such as aluminum.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8597377A JPS5422187A (en) | 1977-07-20 | 1977-07-20 | Photoelectric converting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8597377A JPS5422187A (en) | 1977-07-20 | 1977-07-20 | Photoelectric converting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5422187A JPS5422187A (en) | 1979-02-19 |
| JPS623595B2 true JPS623595B2 (en) | 1987-01-26 |
Family
ID=13873657
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8597377A Granted JPS5422187A (en) | 1977-07-20 | 1977-07-20 | Photoelectric converting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5422187A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5672176A (en) * | 1979-11-15 | 1981-06-16 | Ishinoko Kogyo:Kk | Production of saw |
| JPH0780722A (en) * | 1993-09-16 | 1995-03-28 | Shingen Kogyo Kk | Saw blade and method for manufacturing saw blade |
-
1977
- 1977-07-20 JP JP8597377A patent/JPS5422187A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5422187A (en) | 1979-02-19 |
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