JP2000349365A - Photoelectric current multiplier element - Google Patents
Photoelectric current multiplier elementInfo
- Publication number
- JP2000349365A JP2000349365A JP11159494A JP15949499A JP2000349365A JP 2000349365 A JP2000349365 A JP 2000349365A JP 11159494 A JP11159494 A JP 11159494A JP 15949499 A JP15949499 A JP 15949499A JP 2000349365 A JP2000349365 A JP 2000349365A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- layer
- photocurrent
- ito electrode
- ito
- 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.)
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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
- Y02E10/549—Organic PV cells
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光電流増倍効果に
よる光電変換を利用し、得た電子を有機エレクトロルミ
ネッセンス（ＥＬ）発光の原理を用いて再び光に変換す
る光−光変換素子としての光電流増倍素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-to-light conversion element for converting obtained electrons into light again using the principle of organic electroluminescence (EL) by utilizing photoelectric conversion by a photocurrent multiplication effect. And a photocurrent multiplying device.
【０００２】[0002]
【従来の技術】図６は増倍現象が確認されている光電流
増倍素子の断面図である。この光電流増倍素子１１は、
透明なガラス基板からなる素子基板２の内面に、ＩＴＯ
膜によるＩＴＯ電極３と、図７の構造式で示される厚さ
５００ｎｍの蒸着膜からなるＮＴＣＤＡ（ナフタレンテ
トラカルボン酸）層５と、厚さ４００ｎｍのＡｕ蒸着膜
からなるＡｕ電極６とが順次積層形成されたものであ
り、Ａｕ電極６には駆動電源１０の−極が接続され、Ｉ
ＴＯ電極３には駆動電源１０の＋極が接続されている。2. Description of the Related Art FIG. 6 is a cross-sectional view of a photocurrent multiplier in which a multiplication phenomenon has been confirmed. This photocurrent multiplier 11 is
ITO on the inner surface of the element substrate 2 made of a transparent glass substrate
An ITO electrode 3 of a film, an NTCDA (naphthalenetetracarboxylic acid) layer 5 of a 500 nm-thick vapor-deposited film represented by the structural formula in FIG. 7 and an Au electrode 6 of a 400 nm-thick Au vapor-deposited film are sequentially laminated. The negative electrode of the drive power supply 10 is connected to the Au electrode 6 and
The positive electrode of the drive power supply 10 is connected to the TO electrode 3.
【０００３】上記構成による光電流増倍素子１１におい
て、両電極３，６間に所定の電圧を印加し、Ａｕ電極６
の外側から光を照射する。この光の照射によって生成し
たホール（正孔）は、−極であるＡｕ電極６の近傍にト
ラップホールとして蓄積される。その結果、ＮＴＣＤＡ
層５とＡｕ電極６の界面に電界が集中し、−極（Ａｕ電
極６）から電子注入が起こって増倍現象が発生する。In the photocurrent multiplying element 11 having the above-described structure, a predetermined voltage is applied between the electrodes 3 and 6 so that the Au electrode 6
Irradiate light from outside. The holes (holes) generated by this light irradiation are accumulated as trap holes in the vicinity of the Au electrode 6, which is the negative electrode. As a result, NTCDA
An electric field concentrates on the interface between the layer 5 and the Au electrode 6, and electron injection occurs from the negative electrode (Au electrode 6) to cause a multiplication phenomenon.
【０００４】具体的には、真空度０．１Ｐａの室温下に
おいて、４００ｎｍの単色光の照射により、増倍率数十
万を超える増倍光電流が確認され、またＳ／Ｎ比につい
ては約３０倍前後の値が確認されている。More specifically, a multiplied photocurrent exceeding several hundred thousand is confirmed by irradiation of monochromatic light of 400 nm at room temperature with a degree of vacuum of 0.1 Pa, and the S / N ratio is about 30. A value around twice has been confirmed.
【０００５】ここで、前記増倍率（光電流量子効率）と
は、光電流として流れたキャリア数を有機光電層が吸収
したフォトン数で割って算出した数値である。また、Ｓ
／Ｎ比は、光電流・暗電流比であり、光電流（光照射し
て電圧を印加した時に流れる電流）を暗電流（光照射を
せずに電圧を印加した時に流れる電流）で割って算出し
た数値である。これら増倍率とＳ／Ｎ比とは、印加電圧
に対して相反関係を示している。すなわち、素子が破壊
するまでは、電圧を上げることにより、増倍率は上昇
し、逆にＳ／Ｎ比は減少することが確認されている。具
体的数値を示すと、上記光電流増倍素子１１において、
印加電圧２５Ｖのときに増倍率３万倍、Ｓ／Ｎ比６倍を
示し、印加電圧３０Ｖのときに増倍率１１万倍、Ｓ／Ｎ
比５倍を示す。Here, the multiplication factor (photocurrent quantum efficiency) is a numerical value calculated by dividing the number of carriers flowing as photocurrent by the number of photons absorbed by the organic photoelectric layer. Also, S
The / N ratio is a photocurrent / dark current ratio, and is obtained by dividing photocurrent (current flowing when voltage is applied by light irradiation) by dark current (current flowing when voltage is applied without light irradiation). It is a calculated numerical value. The multiplication factor and the S / N ratio show a reciprocal relationship with the applied voltage. That is, it has been confirmed that by increasing the voltage, the multiplication factor increases and the S / N ratio decreases until the element is destroyed. To show specific numerical values, in the photomultiplier 11 described above,
When the applied voltage is 25 V, the multiplication factor is 30,000, and the S / N ratio is 6 times. When the applied voltage is 30 V, the multiplication factor is 110,000, and the S / N ratio is S / N.
The ratio is 5 times.
【０００６】この増倍現象はペリレン顔料、キナクリド
ン顔料、フタロシアニン顔料においても低温域で確認さ
れている。[0006] This multiplication phenomenon has also been confirmed in the low temperature range for perylene pigments, quinacridone pigments and phthalocyanine pigments.
【０００７】[0007]
【発明が解決しようとする課題】ここで、上述した構造
の従来の光電流増倍素子１１について、固体素子への製
品化を想定して大気中の室温状態にて素子特性を確認し
た。Here, the characteristics of the conventional photomultiplier element 11 having the above-described structure were confirmed at room temperature in the air, assuming commercialization as a solid-state element.
【０００８】その結果、上記従来の光電流増倍素子１１
によれば、素子破壊までの増倍率は約１１万倍程度を確
認できたが、Ｓ／Ｎ比については５倍程度であり、雑音
特性（熱雑音、ショット雑音等）が劣っていた。As a result, the conventional photomultiplier 11
According to the results, the multiplication factor up to the destruction of the element was confirmed to be about 110,000 times, but the S / N ratio was about 5 times, and the noise characteristics (thermal noise, shot noise, etc.) were inferior.
【０００９】したがって、固体素子として実用化するに
は、増倍率が大きいだけでは不十分であり、暗電流を抑
えてＳ／Ｎ比を極力大きくする必要があった。Therefore, for practical use as a solid-state device, it is not sufficient to increase the multiplication factor alone, and it is necessary to suppress the dark current and increase the S / N ratio as much as possible.
【００１０】そこで、本発明は、上記問題点に鑑みてな
されたものであり、増倍率をある程度維持しながら暗電
流を抑えてＳ／Ｎ比を大きくすることができる光電流増
倍素子を提供することを目的としている。Accordingly, the present invention has been made in view of the above problems, and provides a photocurrent multiplier capable of increasing the S / N ratio by suppressing the dark current while maintaining the gain to some extent. It is intended to be.
【００１１】[0011]
【課題を解決するための手段】上記目的を達成するた
め、請求項１の発明は、少なくとも光照射側が透光性を
示す電極からなる一対の電極と、前記一対の電極間に設
けられた光電効果を示す有機光電材料層と、前記一対の
電極のうちの陰極電極をなす第１電極と前記有機光電材
料層との間に設けられたキャリアー選択性のあるバッフ
ァー層とを備えたことを特徴とする。In order to achieve the above object, the invention according to claim 1 is directed to a pair of electrodes, at least on the light-irradiating side, made of a translucent electrode, and a photoelectric converter provided between the pair of electrodes. An organic photoelectric material layer exhibiting an effect, and a buffer layer having carrier selectivity provided between the first electrode serving as a cathode electrode of the pair of electrodes and the organic photoelectric material layer. And
【００１２】請求項２の発明は、透光性を有する第１電
極と、前記第１電極に対向して設けられた光が照射され
る側の第２電極と、前記第１電極と前記第２電極との間
に設けられた光電効果を示す有機光電材料層と、前記第
１電極と前記有機光電材料層との間に設けられたキャリ
アー選択性のあるバッファー層と、前記第１電極に−電
圧を印加し、前記第２電極に＋電圧を印加する駆動電源
とを備えたことを特徴とする。According to a second aspect of the present invention, there is provided a first electrode having a light-transmitting property, a second electrode provided to face the first electrode to be irradiated with light, the first electrode and the first electrode. An organic photoelectric material layer exhibiting a photoelectric effect provided between the two electrodes; a buffer layer having carrier selectivity provided between the first electrode and the organic photoelectric material layer; A driving power supply for applying a negative voltage and applying a positive voltage to the second electrode.
【００１３】請求項３の発明は、ＩＴＯ電極と、前記Ｉ
ＴＯ電極に対向して設けられた光が照射される側のＡｕ
電極と、前記Ａｕ電極と前記ＩＴＯ電極との間に設けら
れたＮＴＣＤＡ層と、前記ＩＴＯ電極と前記ＮＴＣＤＡ
層との間に設けられたキャリアー選択性のあるバッファ
ー層と、前記ＩＴＯ電極に−電圧を印加し、前記Ａｕ電
極に＋電圧を印加する駆動電源とを備えたことを特徴と
する。According to a third aspect of the present invention, an ITO electrode and the I electrode
Au on the side irradiated with light provided opposite to the TO electrode
An electrode, an NTCDA layer provided between the Au electrode and the ITO electrode, the ITO electrode and the NTCDA
A buffer layer having carrier selectivity provided between the first and second layers and a drive power supply for applying a negative voltage to the ITO electrode and applying a positive voltage to the Au electrode.
【００１４】請求項４の発明は、請求項１又は２の光電
流増倍素子において、前記第１電極の仕事関数と前記バ
ッファー層のＬＵＭＯの差が０．５ｅＶ以上であること
を特徴とする。According to a fourth aspect of the present invention, in the photocurrent multiplier of the first or second aspect, the difference between the work function of the first electrode and the LUMO of the buffer layer is 0.5 eV or more. .
【００１５】請求項５の発明は、請求項１〜４のいずれ
かの光電流増倍素子において、前記バッファー層がＴＡ
Ｚ又はＢＣＰからなることを特徴とする。According to a fifth aspect of the present invention, in the photocurrent multiplying device according to any one of the first to fourth aspects, the buffer layer is made of TA.
Z or BCP.
【００１６】請求項６の発明は、請求項３の光電流増倍
素子において、前記ＩＴＯ電極を設けるための透光性の
基板を有し、前記ＩＴＯ電極と前記Ａｕ電極と前記ＮＴ
ＣＤＡ層と前記バッファー層を封止する外囲器を備えた
ことを特徴とする。According to a sixth aspect of the present invention, in the photomultiplier according to the third aspect, there is provided a light-transmitting substrate for providing the ITO electrode, wherein the ITO electrode, the Au electrode, and the NT are provided.
An envelope for sealing the CDA layer and the buffer layer is provided.
【００１７】請求項７の発明は、請求項６の光電流増倍
素子において、前記外囲器の内部がドライ雰囲気に置換
されていることを特徴とする。According to a seventh aspect of the present invention, in the photocurrent multiplier of the sixth aspect, the inside of the envelope is replaced with a dry atmosphere.
【００１８】[0018]
【発明の実施の形態】図１は本発明による光電流増倍素
子の実施の形態を示す図である。なお、図６の従来の光
電流増倍素子と同一の構成要素には同一番号を付して説
明する。FIG. 1 is a diagram showing an embodiment of a photocurrent multiplier according to the present invention. The same components as those of the conventional photomultiplier shown in FIG. 6 are denoted by the same reference numerals.
【００１９】本実施の形態の光電流増倍素子１は、従来
の光電流増倍素子１１におけるＩＴＯ電極３と有機光電
材料層５との間にキャリアー選択性のあるバッファー層
４を介在させ、ＩＴＯ電極３を陰極電極としている。こ
れにより、従来の光電流増倍素子１１と比較して、印加
電圧に対し、増倍効果増大と暗電流の低減によりＳ／Ｎ
比の改善を図っている。The photocurrent multiplier 1 of the present embodiment has a carrier-selective buffer layer 4 between the ITO electrode 3 and the organic photoelectric material layer 5 in the conventional photocurrent multiplier 11, The ITO electrode 3 is used as a cathode electrode. As a result, compared with the conventional photomultiplier element 11, the S / N ratio is increased by increasing the multiplication effect and reducing the dark current with respect to the applied voltage.
The ratio is being improved.
【００２０】以下、図１に基いて具体的に本例の光電流
増倍素子１の構造を説明する。Hereinafter, the structure of the photomultiplier 1 of this embodiment will be specifically described with reference to FIG.
【００２１】図１に示す光電流増倍素子１は、絶縁性及
び透明性を有するガラス基板からなる素子基板２を基部
としている。この素子基板２の内面には、第１電極とし
てのＩＴＯ膜からなるＩＴＯ電極３が所定パターン形状
に形成されている。このＩＴＯ電極３の上には、キャリ
アー選択性（ホールブロッキング性、電子輸送性）のあ
るバッファー層として、図２に示す構造式からなる厚さ
１０ｎｍの薄膜によるＴＡＺ（トリアゾール）層４が形
成されている。The photocurrent multiplying element 1 shown in FIG. 1 is based on an element substrate 2 made of a glass substrate having insulation and transparency. On the inner surface of the element substrate 2, an ITO electrode 3 made of an ITO film as a first electrode is formed in a predetermined pattern. On this ITO electrode 3, as a buffer layer having carrier selectivity (hole blocking property, electron transport property), a TAZ (triazole) layer 4 of a 10 nm-thick thin film having the structural formula shown in FIG. 2 is formed. ing.
【００２２】ＴＡＺ層４の上には、光電効果を示す有機
光電材料層として、厚さ５００ｎｍのＮＴＣＤＡ（ナフ
タレンテトラカルボン酸）層５が形成されている。ＮＴ
ＣＤＡ層５の上には、第２電極としての金属からなる透
光性電極６が形成されている。本例における透光性電極
６は、ＮＴＣＤＡ層５の上に厚さ２０ｎｍのＡｕ薄膜で
形成されたＡｕ電極からなる。On the TAZ layer 4, an NTCDA (naphthalenetetracarboxylic acid) layer 5 having a thickness of 500 nm is formed as an organic photoelectric material layer exhibiting a photoelectric effect. NT
On the CDA layer 5, a translucent electrode 6 made of metal as a second electrode is formed. The translucent electrode 6 in this example is an Au electrode formed of a 20 nm-thick Au thin film on the NTCDA layer 5.
【００２３】なお、バッファー層としてのＴＡＺ層４、
光電効果を示すＮＴＣＤＡ層５、透光性電極としてのＡ
ｕ電極６は、蒸着装置内で抵抗加熱により大気中に曝す
ことなくＩＴＯ膜付きの素子基板２の上に順次成膜され
る。The TAZ layer 4 as a buffer layer,
NTCDA layer 5 exhibiting photoelectric effect, A as translucent electrode
The u-electrode 6 is sequentially formed on the element substrate 2 with the ITO film without being exposed to the atmosphere by resistance heating in a vapor deposition device.
【００２４】図１に示すように、ＩＴＯ電極３が形成さ
れた素子基板２と、Ａｕ電極６の近傍に配置された透光
性を有する封止部材（例えばガラス基板）７との間は封
着材８で封止される。これにより、密閉されたパネル状
の外囲器９を構成する。As shown in FIG. 1, a sealing is provided between the element substrate 2 on which the ITO electrode 3 is formed and a light-transmitting sealing member (eg, a glass substrate) 7 disposed near the Au electrode 6. It is sealed with the material 8. Thus, a sealed panel-shaped envelope 9 is formed.
【００２５】具体的には、封止部材７の外周縁部分に紫
外線硬化樹脂による封着材８を塗布し、ドライエアーで
置換したグローボックス内で大気に曝すことなく、封止
部材７を素子基板２に張り付け、紫外線で紫外線硬化樹
脂を硬化固定する。なお、外囲器９の内部は、ドライ雰
囲気が保たれていればよく、ドライエアーに限らず、ド
ライ窒素の他、高真空状態に置換してもよい。More specifically, a sealing material 8 made of an ultraviolet curable resin is applied to the outer peripheral edge portion of the sealing member 7, and the sealing member 7 is exposed to the air in a glow box replaced with dry air. It is attached to the substrate 2 and the ultraviolet curing resin is cured and fixed with ultraviolet light. Note that the inside of the envelope 9 only needs to maintain a dry atmosphere, and is not limited to dry air, and may be replaced with dry nitrogen or a high vacuum state.
【００２６】Ａｕ電極６の一部は、同一材料により一体
形成された所定パターンの配線を介して素子基板２の端
部に引き出されており、駆動電源１０の＋極に接続され
ている。同様に、ＩＴＯ電極３の一部も、同一材料によ
り一体形成された所定パターンの配線を介して素子基板
２の端部に引き出されており、駆動電源１０の−極に接
続されている。そして、これら一対の電極（ＩＴＯ電極
３、Ａｕ電極６）間には所定の電圧が印加されるように
なっている。A part of the Au electrode 6 is led out to the end of the element substrate 2 through a wiring of a predetermined pattern integrally formed of the same material, and is connected to the positive pole of the driving power supply 10. Similarly, a part of the ITO electrode 3 is also drawn out to the end of the element substrate 2 via a wiring of a predetermined pattern integrally formed of the same material, and is connected to the negative pole of the driving power supply 10. A predetermined voltage is applied between the pair of electrodes (the ITO electrode 3 and the Au electrode 6).
【００２７】ここで、上記光電流増倍素子１において、
ＩＴＯ電極３側をマイナスに電圧印加し、波長４００ｎ
ｍ、照度８μＷ／ｃｍ2 の単色光をＡｕ電極６側に照射
した時の室温における光電流と、暗状態での暗電流をそ
れぞれの印加電圧に対して測定し、素子が破壊せずに機
能するまでの印加電圧、増倍率（光電流量子収率）及び
Ｓ／Ｎ比（明暗電流比）を算出した。Here, in the photocurrent multiplier 1,
A negative voltage is applied to the ITO electrode 3 side, and the wavelength is 400 n
m, the photocurrent at room temperature when monochromatic light having an illuminance of 8 μW / cm 2 was irradiated on the Au electrode 6 side, and the dark current in the dark state were measured with respect to each applied voltage, and the element functioned without being destroyed. Applied voltage, multiplication factor (photocurrent quantum yield) and S / N ratio (light / dark current ratio) were calculated.
【００２８】また、本例の光電流増倍素子１との特性比
較のため、バッファー層としてのＴＡＺ層４がない構造
の従来の光電流増倍素子（ＩＴＯ電極３／ＮＴＣＤＡ層
５（５００ｎｍ）／Ａｕ電極６（２０ｎｍ））を作成
し、同等の条件で実験を行った。In order to compare the characteristics with the photocurrent multiplier 1 of this embodiment, a conventional photocurrent multiplier (ITO electrode 3 / NTCDA layer 5 (500 nm)) having no TAZ layer 4 as a buffer layer was used. / Au electrode 6 (20 nm)) and an experiment was performed under the same conditions.
【００２９】その結果、下記表１〜表３に示す結果が得
られた。As a result, the results shown in the following Tables 1 to 3 were obtained.
【００３０】[0030]
【表１】 [Table 1]
【００３１】[0031]
【表２】 [Table 2]
【００３２】[0032]
【表３】 [Table 3]
【００３３】そして、表１に示すように、本例の光電流
増倍素子１によれば、印加電圧３０Ｖにおいて、増倍率
３万倍、Ｓ／Ｎ比８０倍を記録した。これに対し、従来
の光電流増倍素子１１では、表３に示すように、印加電
圧３０Ｖにおいて、増倍率が１１万倍と本例の光電流増
倍素子１より優れてはいるものの、Ｓ／Ｎ比が５倍と本
例の光電流増倍素子１よりも極めて低いという結果が得
られた。As shown in Table 1, according to the photocurrent multiplying element 1 of this example, at an applied voltage of 30 V, a multiplication factor of 30,000 and an S / N ratio of 80 were recorded. On the other hand, as shown in Table 3, the conventional photocurrent multiplying element 11 has a multiplication factor of 110,000 times at an applied voltage of 30 V, which is superior to the photocurrent multiplying element 1 of the present example. The result was that the / N ratio was 5 times, which was extremely lower than that of the photocurrent multiplier 1 of this example.
【００３４】また、表１に示すように、従来の光電流増
倍素子１１において、Ｓ／Ｎ比の改善を優先し、上記本
例の光電流増倍素子１に近づくようにしたが、印加電圧
１３Ｖのときに最高２５倍のＳ／Ｎ比しか得られず、印
加電圧を高くしても低くしてもＳ／Ｎ比が下がり、逆に
増倍率が０．２万倍と本例の光電流増倍素子１よりも極
めて低くなるという結果が得られた。Further, as shown in Table 1, in the conventional photocurrent multiplying element 11, the improvement of the S / N ratio was prioritized so as to approach the photocurrent multiplying element 1 of the present embodiment. At a voltage of 13 V, only a maximum of 25 times the S / N ratio can be obtained, and the S / N ratio decreases even if the applied voltage is increased or decreased. The result was extremely lower than that of the photocurrent multiplier 1.
【００３５】さらに、表２に示すように、従来の光電流
増倍素子１１において、増倍率を本例の光電流増倍素子
１と同一の３万倍に設定すると、印加電圧２５Ｖで６倍
のＳ／Ｎ比しか得られなかった。Further, as shown in Table 2, if the multiplication factor of the conventional photocurrent multiplication element 11 is set to 30,000 times, which is the same as that of the photocurrent multiplication element 1 of the present embodiment, it is 6 times at an applied voltage of 25V. Only the S / N ratio of was obtained.
【００３６】すなわち、本例の光電流増倍素子１によれ
ば、同一の電圧を印加した場合、従来の光電流増倍素子
１１よりもＳ／Ｎ比を大幅に改善することができる。That is, according to the photocurrent multiplier 1 of this embodiment, when the same voltage is applied, the S / N ratio can be greatly improved as compared with the conventional photocurrent multiplier 11.
【００３７】そして、本例の光電流増倍素子１における
Ｓ／Ｎ比の改善は、ＩＴＯ電極３と光電効果を示すＮＴ
ＣＤＡ層５との間にキャリアー選択性（ホールブロック
性、電子輸送性）のあるＴＡＺ層４をバッファー層とし
て積層し、ＩＴＯ電極３にマイナス電圧を印加すること
によって得られる。The improvement of the S / N ratio in the photocurrent multiplying element 1 of the present embodiment is achieved by using the ITO electrode 3 and the NT having the photoelectric effect.
It is obtained by laminating a TAZ layer 4 having carrier selectivity (hole blocking property, electron transport property) as a buffer layer between the CDA layer 5 and applying a negative voltage to the ITO electrode 3.
【００３８】このメカニズムについては、ＩＴＯ電極３
とＴＡＺ層４の下記（１）〜（３）の特性から以下のよ
うに推測される。 （１）ＩＴＯ電極３はＰ型特性を持ち、マイナス印加時
は電子注入し難い。 （２）ＴＡＺ層４はホールに対してブロック性を持ち、
電子は輸送する。 （３）ＩＴＯ電極３の仕事関数とＴＡＺ層４のＬＵＭＯ
の差が０．５ｅＶ以上と大きく電子注入がし難い。This mechanism is described in detail in
From the following characteristics (1) to (3) of the TAZ layer 4, it is estimated as follows. (1) The ITO electrode 3 has a P-type characteristic, and it is difficult to inject electrons when a negative voltage is applied. (2) The TAZ layer 4 has a blocking property for holes,
Electrons transport. (3) Work function of ITO electrode 3 and LUMO of TAZ layer 4
Is as large as 0.5 eV or more, making electron injection difficult.
【００３９】そして、Ａｕ電極６の外側から光が照射さ
れていない状態で、ＩＴＯ電極３にマイナス電圧が印加
された場合には、ＩＴＯ電極３から電子が注入し難く、
Ａｕ電極６からのホールの注入も少なくＴＡＺ層４にて
ブロックされる。このため、印加電圧を上げても暗電流
は抑えられる。When a negative voltage is applied to the ITO electrode 3 in a state where light is not irradiated from the outside of the Au electrode 6, electrons are hardly injected from the ITO electrode 3,
The injection of holes from the Au electrode 6 is also small and is blocked by the TAZ layer 4. Therefore, the dark current can be suppressed even when the applied voltage is increased.
【００４０】これに対し、Ａｕ電極６の外側から光が照
射された時は、ＮＴＣＤＡ層５の内部で生成された光キ
ャリア（ホール）が効率良くＴＡＺ層４にてブロック
（トラップ）され、ＩＴＯ電極３との界面に高電界が発
生し、強制的にＩＴＯ電極３より電子がトンネル注入さ
れ、光電流のみの増倍が生じ、しかも印加電圧を上げる
ことにより増倍を増す事が出来るものと推測される。On the other hand, when light is irradiated from the outside of the Au electrode 6, photocarriers (holes) generated inside the NTCDA layer 5 are efficiently blocked (trapped) by the TAZ layer 4, and ITO A high electric field is generated at the interface with the electrode 3, electrons are forcibly tunnel injected from the ITO electrode 3, multiplication of only the photocurrent occurs, and the multiplication can be increased by increasing the applied voltage. Guessed.
【００４１】以上説明した推測より、暗電流の低減、光
電流のみの増倍によってＳ／Ｎ比が改善される。すなわ
ち、素子破壊範囲以内であれば、印加電圧を上げても暗
電流の増加は殆ど見られず、光電流のみが増加し、増倍
率及びＳ／Ｎ比共に向上させることができる。As described above, the S / N ratio is improved by reducing the dark current and multiplying only the photocurrent. That is, within the element breakdown range, even if the applied voltage is increased, almost no increase in the dark current is observed, only the photocurrent increases, and both the multiplication factor and the S / N ratio can be improved.
【００４２】ここで、図４は上記光電流増倍素子１のＴ
ＡＺ層４の膜厚を変えたときの印加電圧に対する増倍度
を示す特性図、図５は同ＴＡＺ層の膜厚を変えたときの
印加電圧に対するＳ／Ｎ比を示す特性図である。なお、
Ａｕ電極６の外側から照射される光の照射波長を４００
ｎｍ、照射強度を７．６μｗ／ｃｍ2 とし、ＴＡＺ層４
の膜厚を５０Å、１００Å、２００Åと変化させてい
る。FIG. 4 shows the T of the photocurrent multiplying element 1.
FIG. 5 is a characteristic diagram showing the multiplication factor with respect to the applied voltage when the thickness of the AZ layer 4 is changed, and FIG. 5 is a characteristic diagram showing the S / N ratio with respect to the applied voltage when the thickness of the TAZ layer is changed. In addition,
The irradiation wavelength of light irradiated from the outside of the Au electrode 6 is 400
nm, the irradiation intensity was 7.6 μw / cm 2 , and the TAZ layer 4
Is changed to 50 °, 100 °, and 200 °.
【００４３】上記図４及び図５からも明らかなように、
ＴＡＺ層４の厚さを制御することにより増倍率及びＳ／
Ｎ比を調整することができる。そして、ＴＡＺ層４の厚
さを厚くすれば、増倍率は減少するが、Ｓ／Ｎ比をさら
に改善することができる。As is clear from FIGS. 4 and 5,
By controlling the thickness of the TAZ layer 4, the multiplication factor and S /
The N ratio can be adjusted. When the thickness of the TAZ layer 4 is increased, the multiplication factor decreases, but the S / N ratio can be further improved.
【００４４】以上の事から次のような改善効果が得られ
る。増倍率を比較的維持しながらＳ／Ｎ比（増倍光電流
に対する暗電流の比）を１６倍以上に改善可能であり、
例えば光センサ、光増幅器、波長検出器として固体素子
へ展開した時の雑音特性（熱雑音・ショット雑音等）が
向上し、感度の信頼性が向上する。From the above, the following improvement effects can be obtained. The S / N ratio (ratio of dark current to multiplied photocurrent) can be improved to 16 times or more while relatively maintaining the multiplication factor.
For example, noise characteristics (thermal noise, shot noise, etc.) when developed into a solid-state device as an optical sensor, an optical amplifier, and a wavelength detector are improved, and the reliability of sensitivity is improved.
【００４５】両電極（ＩＴＯ電極３、Ａｕ電極６）間の
印加電圧によって増倍率及びＳ／Ｎ比が制御でき、用途
に応じて特性のコントロールが可能である。The multiplication factor and the S / N ratio can be controlled by the voltage applied between both electrodes (ITO electrode 3 and Au electrode 6), and the characteristics can be controlled according to the application.
【００４６】ＴＡＺ層４の膜厚制御により、素子特性と
して増倍率及びＳ／Ｎ比を制御できるので、実使用に合
った固体素子が可能となる。By controlling the film thickness of the TAZ layer 4, the multiplication factor and the S / N ratio can be controlled as device characteristics, so that a solid-state device suitable for actual use can be realized.
【００４７】ところで、上記実施の形態では、バッファ
ー層としてＴＡＺ層４を用いた構成について説明した
が、バッファー層はキャリアー選択性（ホールブロック
性、電子輸送性）のある層であればよい。例えば図３に
示す構造式からなるＢＣＰ（バソクプロイン）等の層を
バッファー層としても同様の効果が得られる。In the above embodiment, the configuration using the TAZ layer 4 as the buffer layer has been described, but the buffer layer may be any layer having carrier selectivity (hole blocking property, electron transport property). For example, the same effect can be obtained by using a layer such as BCP (basocuproin) having the structural formula shown in FIG. 3 as a buffer layer.
【００４８】[0048]
【発明の効果】以上の説明で明らかなように、本発明の
光電流増倍素子は、一対の電極間に光電効果を示す有機
光電材料層を挟んだ構造において、一対の電極のうちの
陰極電極と有機光電材料層との間にキャリアー選択性
（ホールブロッキング性、電子輸送性）のあるバッファ
ー層を介在させている。これにより、光照射時には、有
機光電材料層で生成された光キャリア（ホール）が効率
良くバッファー層にてブロック（トラップ）され、陰極
電極との界面に高電界が発生し、強制的に陰極電極より
電子がトンネル注入され、光電流のみの増倍が生じ、し
かも印加電圧を上げることにより増倍を増す。その結
果、増倍率をある程度維持しながら暗電流を抑え、従来
の素子構成に比べてＳ／Ｎ比を大幅に改善することがで
きる。As is apparent from the above description, the photocurrent multiplier of the present invention has a structure in which an organic photoelectric material layer exhibiting a photoelectric effect is sandwiched between a pair of electrodes. A buffer layer having carrier selectivity (hole blocking property, electron transport property) is interposed between the electrode and the organic photoelectric material layer. As a result, at the time of light irradiation, photocarriers (holes) generated in the organic photoelectric material layer are efficiently blocked (trapped) in the buffer layer, and a high electric field is generated at the interface with the cathode electrode. More electrons are injected into the tunnel and multiplication of only the photocurrent occurs, and the multiplication is increased by increasing the applied voltage. As a result, the dark current can be suppressed while maintaining the multiplication factor to some extent, and the S / N ratio can be greatly improved as compared with the conventional element configuration.
【図１】本発明による光電流増倍素子の一例の断面図FIG. 1 is a cross-sectional view of an example of a photocurrent multiplier according to the present invention.
【図２】本発明においてバッファー層を構成するＴＡＺ
の構造式を示す図FIG. 2 shows a TAZ constituting a buffer layer in the present invention.
Diagram showing the structural formula of
【図３】本発明においてバッファー層を構成するＢＣＰ
の構造式を示す図FIG. 3 shows a BCP constituting a buffer layer in the present invention.
Diagram showing the structural formula of
【図４】本発明の光電流増倍素子におけるバッファー層
の膜厚を変えたときの印加電圧に対する増倍度を示す特
性図FIG. 4 is a characteristic diagram showing the degree of multiplication with respect to applied voltage when the thickness of the buffer layer is changed in the photocurrent multiplier of the present invention.
【図５】本発明の光電流増倍素子におけるバッファー層
の膜厚を変えたときの印加電圧に対するＳ／Ｎ比を示す
特性図FIG. 5 is a characteristic diagram showing an S / N ratio with respect to an applied voltage when the thickness of a buffer layer is changed in the photocurrent multiplier of the present invention.
【図６】従来の光電流増倍素子の一例の断面図FIG. 6 is a sectional view of an example of a conventional photocurrent multiplier.
【図７】従来の光電流増倍素子において有機層に使用さ
れているＮＴＣＤＡの構造式を示す図FIG. 7 is a diagram showing a structural formula of NTCDA used for an organic layer in a conventional photocurrent multiplier.
１…光電流増倍素子、２…素子基板、３…ＩＴＯ電極
（第１電極）、４…ＴＡＺ層（バッファー層）、５…Ｎ
ＴＣＤＡ層（有機光電材料層）、６…透光性電極（第２
電極）、７…封止部材、９…外囲器、１０…駆動電源。REFERENCE SIGNS LIST 1 photomultiplier element 2 element substrate 3 ITO electrode (first electrode) 4 TAZ layer (buffer layer) 5 N
TCDA layer (organic photoelectric material layer), 6... Translucent electrode (second
Electrodes), 7: sealing member, 9: envelope, 10: drive power supply.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 田中 哲 千葉県茂原市大芝629 双葉電子工業株式 会社内 (72)発明者 福田 辰男 千葉県茂原市大芝629 双葉電子工業株式 会社内 (72)発明者 飯泉 安広 千葉県茂原市大芝629 双葉電子工業株式 会社内 Ｆターム(参考） 5F088 AA20 AB11 AB13 BA01 BA04 DA13 FA04 FA05 JA07 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsu Tanaka 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Industries Co., Ltd. (72) Inventor Tatsuo Fukuda 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. Inventor Yasuhiro Iizumi 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. F-term (reference) 5F088 AA20 AB11 AB13 BA01 BA04 DA13 FA04 FA05 JA07
Claims (7)
からなる一対の電極と、 前記一対の電極間に設けられた光電効果を示す有機光電
材料層と、 前記一対の電極のうちの陰極電極をなす第１電極と前記
有機光電材料層との間に設けられたキャリアー選択性の
あるバッファー層とを備えたことを特徴とする光電流増
倍素子。1. A pair of electrodes at least including a light-transmitting electrode on a light irradiation side; an organic photoelectric material layer having a photoelectric effect provided between the pair of electrodes; and a cathode electrode of the pair of electrodes. And a buffer layer having carrier selectivity provided between the first electrode and the organic photoelectric material layer.
第２電極と、 前記第１電極と前記第２電極との間に設けられた光電効
果を示す有機光電材料層と、 前記第１電極と前記有機光電材料層との間に設けられた
キャリアー選択性のあるバッファー層と、 前記第１電極に−電圧を印加し、前記第２電極に＋電圧
を印加する駆動電源とを備えたことを特徴とする光電流
増倍素子。2. A first electrode having a light-transmitting property, a second electrode provided to face the first electrode and irradiated with light, and between the first electrode and the second electrode. An organic photoelectric material layer exhibiting a photoelectric effect, a buffer layer having carrier selectivity provided between the first electrode and the organic photoelectric material layer, and a negative voltage applied to the first electrode. And a drive power supply for applying a positive voltage to the second electrode.
のＡｕ電極と、 前記Ａｕ電極と前記ＩＴＯ電極との間に設けられたＮＴ
ＣＤＡ層と、 前記ＩＴＯ電極と前記ＮＴＣＤＡ層との間に設けられた
キャリアー選択性のあるバッファー層と、 前記ＩＴＯ電極に−電圧を印加し、前記Ａｕ電極に＋電
圧を印加する駆動電源とを備えたことを特徴とする光電
流増倍素子。3. An ITO electrode, an Au electrode on the side irradiated with light provided opposite to the ITO electrode, and a NT provided between the Au electrode and the ITO electrode.
A CDA layer; a buffer layer having carrier selectivity provided between the ITO electrode and the NTCDA layer; and a driving power supply for applying a negative voltage to the ITO electrode and applying a positive voltage to the Au electrode. A photocurrent multiplying element comprising:
ー層のＬＵＭＯの差が０．５ｅＶ以上であることを特徴
とする請求項１又は２記載の光電流増倍素子。4. The photocurrent multiplier according to claim 1, wherein a difference between the work function of the first electrode and the LUMO of the buffer layer is 0.5 eV or more.
らなることを特徴とする請求項１〜４のいずれかに記載
の光電流増倍素子。5. The photocurrent multiplier according to claim 1, wherein said buffer layer is made of TAZ or BCP.
基板を有し、前記ＩＴＯ電極と前記Ａｕ電極と前記ＮＴ
ＣＤＡ層と前記バッファー層を封止する外囲器を備えた
ことを特徴とする請求項３記載の光電流増倍素子。6. A light-transmitting substrate for providing said ITO electrode, wherein said ITO electrode, said Au electrode and said NT
4. The photocurrent multiplier according to claim 3, further comprising an envelope for sealing the CDA layer and the buffer layer.
されていることを特徴とする請求項６記載の光電流増倍
素子。7. The photocurrent multiplier according to claim 6, wherein the inside of the envelope is replaced with a dry atmosphere.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11159494A JP2000349365A (en) | 1999-06-07 | 1999-06-07 | Photoelectric current multiplier element |
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| JP2014514730A (en) * | 2011-02-28 | 2014-06-19 | ユニバーシティ オブ フロリダ リサーチ ファウンデーション，インク． | Photodetector with gain and up-conversion device (EC) |
| JP2014521214A (en) * | 2011-06-30 | 2014-08-25 | ユニバーシティー オブ フロリダ リサーチ ファウンデーション，インコーポレイテッド | Method and apparatus for detecting infrared radiation with gain |
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1999
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|---|---|---|---|---|
| US10700141B2 (en) | 2006-09-29 | 2020-06-30 | University Of Florida Research Foundation, Incorporated | Method and apparatus for infrared detection and display |
| US9997571B2 (en) | 2010-05-24 | 2018-06-12 | University Of Florida Research Foundation, Inc. | Method and apparatus for providing a charge blocking layer on an infrared up-conversion device |
| JP2014514730A (en) * | 2011-02-28 | 2014-06-19 | ユニバーシティ オブ フロリダ リサーチ ファウンデーション，インク． | Photodetector with gain and up-conversion device (EC) |
| JP2014521214A (en) * | 2011-06-30 | 2014-08-25 | ユニバーシティー オブ フロリダ リサーチ ファウンデーション，インコーポレイテッド | Method and apparatus for detecting infrared radiation with gain |
| JP2017175149A (en) * | 2011-06-30 | 2017-09-28 | ユニバーシティー オブ フロリダ リサーチ ファウンデーション, インコーポレイテッドUniversity Of Florida Research Foundation, Inc. | Method and apparatus for detecting infrared radiation with gain |
| US10134815B2 (en) | 2011-06-30 | 2018-11-20 | Nanoholdings, Llc | Method and apparatus for detecting infrared radiation with gain |
| US10749058B2 (en) | 2015-06-11 | 2020-08-18 | University Of Florida Research Foundation, Incorporated | Monodisperse, IR-absorbing nanoparticles and related methods and devices |
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