JPH0371528A - Semiconductor photoelectric surface structure - Google Patents
Semiconductor photoelectric surface structureInfo
- Publication number
- JPH0371528A JPH0371528A JP1207461A JP20746189A JPH0371528A JP H0371528 A JPH0371528 A JP H0371528A JP 1207461 A JP1207461 A JP 1207461A JP 20746189 A JP20746189 A JP 20746189A JP H0371528 A JPH0371528 A JP H0371528A
- Authority
- JP
- Japan
- Prior art keywords
- substrate
- crystal growth
- photocathode
- light
- growth substrate
- 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.)
- Pending
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 23
- 239000000758 substrate Substances 0.000 claims abstract description 41
- 239000013078 crystal Substances 0.000 claims abstract description 32
- 239000000463 material Substances 0.000 claims abstract description 9
- 238000002109 crystal growth method Methods 0.000 claims abstract description 4
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 230000005540 biological transmission Effects 0.000 abstract description 4
- 230000003287 optical effect Effects 0.000 description 3
- 239000011149 active material Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 1
- 241000769223 Thenea Species 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000007847 structural defect Effects 0.000 description 1
Landscapes
- Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
- Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
Abstract
Description
従来、赤外光用半導体光電面としては、Ｓ−１光電面が
知られている。
このＳ−１光電面はその分光感度特性が、広範囲な波長
域に対応しているものの、量子効率が低く、例えば１．
０６μ−の波長光に対しては、０゜０３％（代表値〉で
ある。又、熱電子流が室温において１０−”〜１０−’
２Ａ／ｃｊと非常に大きいので、例えば光電子増倍管に
用いる場合には、−２０℃程度に冷却して使用しなけれ
ばならないという問題点がある。又、前記Ｓ−１光電面
を二次電子増倍器（例えばマルチチＶンネルプレート〉
を内蔵した赤外域イメージインテンシファイヤに利用し
ようとすると、熱電子流が大きいために暗電流が非常に
大きく、実用化できないという問題点がある。
これに対して、１μ鴎以上の波長光に感度を持つ光電陰
極材料として、Ｐ十にドープされた１ｎＧａ Ａｓ Ｐ
や、Ｉｎ Ｇａ Ａｓがある。
これらは、通常、ＩｎＰ又はＱａ Ａｓ又は１ｎＧａ／
ＩＡｓを結晶成長用基板として、この上にエピタキシャ
ル法で光電陰極居が形成されている。
これらを用いた光電面は、紫外光から赤外光（例えば１
．１μｍ）までであり、且つ、例えば１．０６μはの波
長光では０．１−数％の量子効率があり、しかも、半導
体光電面であるがゆえに低暗電流、例えば１０−” 〜
１０−’ ５Ａ／ｄという特性を有している。
（発明が解決しようとする課題１
しかしながら、上記のような光電陰極材料からなる半導
体光電面は、反射型光電面としてのみ使用され、例えば
光電子増倍管にはかろうじて利用可能であるが、場合に
よっては反射型光電面のための構造上の欠点から、大き
な光損失が生じるという問題点がある。従って、イメー
ジ管としては使用できなかった。
更に、赤外光のみに感度を持たせようとすると、別途赤
外光透過フィルタ等を装着しなければならないという問
題点がある。
この発明は、上記従来の問題点に鑑みてなされたもので
あって、量子効率を低くすることなく、透過型光電面こ
して使用可能であり、且つイメージ管としても利用でき
、又、赤外光透過フィルタ等を用いることなく、赤外域
のみに感度を持たせるここができるようにした半導体充
電面構造を提供することを目的とする。
（課題を解決するための手段１
この発明は、結晶成長用基板と、その上に結晶成長法に
より形成された、前記結晶成長用基板のバンドギャップ
より小さいバンドギャップを持っ光電陰極層ε、を有し
てなる半導体光電面構造において、前記結晶成長用基板
を、少なくとも赤外光を透過させる材料から形成し、該
結晶成長用基板を介して前記光電陰極面に光入射させる
ようにして上記目的を達成するものである。
又、前記結晶成長用基板を、可視光を吸収する材料から
形成することにより上記目的を達成するものである。
〔作用］
この発明においては、結晶成長用基板側から光入射をす
ることにより、半導体充電面としての高い効率特性、低
暗電流特性を損うことなく、透過型光電面として利用で
き、更にフィルタを用いることなく赤外域の光のみに感
度を有するように構成できる。
従って、従来不可能であったマイクロチＶンネルプレー
ト内蔵型赤外域イメージインテンシファイヤや、冷却不
要な赤外域用光電子増倍管を可能とするものである。Conventionally, an S-1 photocathode has been known as a semiconductor photocathode for infrared light. Although the S-1 photocathode has spectral sensitivity characteristics that cover a wide range of wavelengths, its quantum efficiency is low, such as 1.
For light with a wavelength of 0.6 μ-, it is 0°03% (typical value). Also, the thermionic current is 10-” to 10-’ at room temperature.
Since it is extremely large at 2 A/cj, there is a problem in that, when used in a photomultiplier tube, for example, it must be cooled to about -20°C. Further, the S-1 photocathode is connected to a secondary electron multiplier (for example, a multi-channel V channel plate).
When trying to use it in an infrared image intensifier with a built-in infrared image intensifier, there is a problem that the dark current is extremely large due to the large thermionic current, making it impossible to put it into practical use. On the other hand, as a photocathode material sensitive to light with a wavelength of 1μ or more, 1nGaAsP doped with P
There is also InGaAs. These are usually InP or Qa As or 1nGa/
IAs is used as a substrate for crystal growth, and a photocathode is formed thereon by an epitaxial method. A photocathode using these materials can be used for light ranging from ultraviolet light to infrared light (for example, 1
．． 1 μm), and has a quantum efficiency of 0.1-several percent for light with a wavelength of, for example, 1.06 μm. Moreover, since it is a semiconductor photocathode, it has a low dark current, e.g.
It has a characteristic of 10-'5A/d. (Problem to be Solved by the Invention 1) However, the semiconductor photocathode made of the photocathode material as described above is used only as a reflective photocathode, and is barely usable for example in photomultiplier tubes. Due to the structural defect of the reflective photocathode, there is a problem in that large optical loss occurs.Therefore, it could not be used as an image tube.Furthermore, if you try to make it sensitive only to infrared light, , there is a problem that an infrared light transmitting filter, etc. must be separately installed.The present invention was made in view of the above-mentioned conventional problems, and it is possible to improve transmission type photoelectrons without lowering the quantum efficiency. To provide a semiconductor charging surface structure which can be used as a surface filter, can also be used as an image tube, and can have sensitivity only in the infrared region without using an infrared light transmitting filter or the like. (Means for Solving the Problem 1) The present invention includes a crystal growth substrate and a crystal growth substrate formed thereon by a crystal growth method, which has a bandgap smaller than the bandgap of the crystal growth substrate. In a semiconductor photocathode structure having a photocathode layer ε, the crystal growth substrate is formed from a material that transmits at least infrared light, and light is incident on the photocathode surface through the crystal growth substrate. In this invention, the above object is achieved by making the crystal growth substrate made of a material that absorbs visible light. [Function] In this invention, By inputting light from the crystal growth substrate side, it can be used as a transmission type photocathode without impairing the high efficiency characteristics and low dark current characteristics of a semiconductor charging surface, and it can also be used as a transmission type photocathode without using a filter. Therefore, it becomes possible to create an infrared image intensifier with a built-in microchannel plate, which was previously impossible, and an infrared photomultiplier tube that does not require cooling.
以下、本発明の実施例を図面を参照して説明する。
この実ｆＩＭ例に係る半導体光Ｎ面１０は、結晶成長用
基板１２と、その上に結晶成長法により形成された、前
記結晶成長用基板１２のバンドギャップよりも小さいバ
ンドギャップを持つ光電陰極層１４と、を備えてなり、
前記結晶成長用基板１２は、例えばＩｎＰから構成され
、光電陰極層１４は、例えばＩｎ Ｇａ Ａｓ Ｐから
構成されている。
又、前記光電陰極層１４は、電子拡散長程度の厚さで、
且つＮＥＡ近くに表面活性処理され、表面活性物質層１
６が形成されている。
この実施例において、光は結晶成長用基板１２側から半
導体光電面に入射させる。
このようにすると、結晶成長用基板１２を通って光Ｎ陰
極層に到達する光は、結晶成長用基板１２のバンドギャ
ップに依存する最短波長λＳよりも長い波長の光となる
（第２図参照）。
光電陰極層１４に入射した光のうち、該光電陰極１１１
４のバンドギャップで決まる閾値波長λＬよりも短い波
長の光は吸収され、光電子を発生させる（第２図破線参
照）。ここで、第２図の破線は、反射モードでの上記半
導体光電面１０の光電面分光感度特性を示す。
これらの光電子は、表面活性物質店１６の表面から効率
良く真空中へ放出される。その結果、得られる特性は第
３図に示されるようになる。
なお、結晶成長用、基板１２としてＩｎＰを用いた場合
は、λｓ＝０．９２μ箇となり、光電陰極層１４としＴ
Ｉ ｎ ｙｐ Ｇ ａ 、、ａ Ａ Ｓ ｐ、ＨＰａ
ｄを用いた場合、λＬ＝１．１μ覆となり、ＱＥｍａｘ
＝７％ａ【１．０６μｍとなる。
又、結晶成長用基板１２としてＧａ Ａｓ 、光電５ｉ
Ｒ１４としてｉｎ ｘＧａ Ａｓ （０，１７＜ｘ〈
０．２ンを用いた場合、２ｓ＝０．８７μｍ、λＬ−１
，１ｕｌｌ、ＱＥｍａＸ−０，１〜数％ａｔ１゜０６μ
ｍとなる。
従って、この実施例によれば、半導体光電面ヒしての高
い効率特性、低暗電流特性を損うことなく、又、フィル
タ等を用いることなく、赤外域のみに感度を有する半導
体光電面を容易に構成することができる。又、従来不可
能であったマイクロチャンネルプレート内蔵型赤外域イ
メージインデンジファイヤ及び冷却不要な赤外域用光電
子増倍管を形成することができる。
又、結晶成長用基板１２として市販の厚さ０゜３ｎ程度
のものをそのまま利用することができるので、低コスト
であると共に、真空中にセルフサポート形式で半導体光
電面を保持することが可能である。
なお、上記実施例において、結晶成長用基板１２はこれ
を単独で用いたものであるが、本発明はこれに限定され
るものでなく、該結晶成長用基板１２は、これと熱膨張
係数の合ったガラス基板に接着したものであってもよい
。又、結晶成長用基板１２は光電陰極層１４（ＩＩに緩
衝層のような中間層を設けた場合も含むものである。
又、前記結晶、成長用基板１２及び光電陰極層１４の材
質は、実施例に限定されるものでなく、結晶成長用基板
１２は少なくとも赤外光を透過させるものであればよい
。
【発明の効果］
本発明は、上記のように構成したので、簡単な構成で、
半導体光電面としての高い効率特性及び低暗電流特性を
損うことなく、又フィルタを用いることなく、赤外域の
みに感度を有するようにすることができ、更に、従来不
可能であったマイクロチャンネルプレート内蔵型赤外イ
メージインデンジファイヤや冷却不能な赤外域用光電子
増倍管を形成することができるという優れた効果を有す
る。Embodiments of the present invention will be described below with reference to the drawings. The semiconductor optical N-plane 10 according to this practical fIM example includes a crystal growth substrate 12 and a photocathode layer formed thereon by a crystal growth method and having a bandgap smaller than that of the crystal growth substrate 12. 14, and
The crystal growth substrate 12 is made of, for example, InP, and the photocathode layer 14 is made of, for example, InGaAsP. Further, the photocathode layer 14 has a thickness approximately equal to the electron diffusion length,
and a surface active material layer 1 which is subjected to surface activation treatment near the NEA.
6 is formed. In this embodiment, light is made incident on the semiconductor photocathode from the crystal growth substrate 12 side. In this way, the light that passes through the crystal growth substrate 12 and reaches the optical N cathode layer has a wavelength longer than the shortest wavelength λS, which depends on the band gap of the crystal growth substrate 12 (see Figure 2). ). Of the light incident on the photocathode layer 14, the photocathode 111
Light with a wavelength shorter than the threshold wavelength λL determined by the bandgap of 4 is absorbed and photoelectrons are generated (see the broken line in FIG. 2). Here, the broken line in FIG. 2 indicates the photocathode spectral sensitivity characteristic of the semiconductor photocathode 10 in the reflection mode. These photoelectrons are efficiently emitted from the surface of the surface-active material store 16 into the vacuum. As a result, the characteristics obtained are as shown in FIG. Note that when InP is used as the substrate 12 for crystal growth, λs=0.92μ, and the photocathode layer 14 is T
I n yp G a ,, a A S p, HPa
When using d, λL = 1.1μ, and QEmax
= 7% a [1.06 μm. In addition, as the crystal growth substrate 12, GaAs, photoelectric 5i
R14 in xGa As (0,17<x〈
When using 0.2mm, 2s=0.87μm, λL-1
,1ull,QEmaX-0,1~several%at1゜06μ
m. Therefore, according to this embodiment, a semiconductor photocathode having sensitivity only in the infrared region can be fabricated without impairing the high efficiency characteristics and low dark current characteristics of a semiconductor photocathode, and without using a filter or the like. Can be easily configured. Furthermore, it is possible to form an infrared image indensifier with a built-in microchannel plate and an infrared photomultiplier tube that does not require cooling, which was previously impossible. Furthermore, since a commercially available substrate with a thickness of about 0°3 nm can be used as it is as the crystal growth substrate 12, the cost is low and the semiconductor photocathode can be held in a self-supporting manner in a vacuum. be. In the above embodiment, the crystal growth substrate 12 is used alone, but the present invention is not limited to this, and the crystal growth substrate 12 has a thermal expansion coefficient that is different from that of the crystal growth substrate 12. It may also be bonded to a matching glass substrate. The crystal growth substrate 12 also includes a case where an intermediate layer such as a buffer layer is provided on the photocathode layer 14 (II). The materials of the crystal, the growth substrate 12, and the photocathode layer 14 are the same as in the embodiment. However, the crystal growth substrate 12 may be any substrate that transmits at least infrared light. [Effects of the Invention] Since the present invention is configured as described above, it has a simple configuration.
It is possible to make it sensitive only in the infrared region without impairing the high efficiency characteristics and low dark current characteristics of a semiconductor photocathode, and without using a filter. Furthermore, it can be made to have sensitivity only in the infrared region, which was previously impossible. It has the excellent effect of being able to form an infrared image indensifier with a built-in plate and a photomultiplier tube for the infrared region that cannot be cooled.
第１図は本発明に係る半導体光電面構造の実施例を示す
断面図、第２図は同実施例における特性を示す線図、第
３図は同実施例の量子効率を示す線図である。
１０・・・半導体光電面、
１２・・・結晶成長用基板、
１４・・・光電陰極層。FIG. 1 is a cross-sectional view showing an embodiment of a semiconductor photocathode structure according to the present invention, FIG. 2 is a diagram showing the characteristics of the same embodiment, and FIG. 3 is a diagram showing the quantum efficiency of the same embodiment. . 10... Semiconductor photocathode, 12... Crystal growth substrate, 14... Photocathode layer.
Claims (2)
成された、前記結晶成長用基板のバンドギャップより小
さいバンドギャップを持つ光電陰極層と、を有してなる
半導体光電面構造において、前記結晶成長用基板を、少
なくとも赤外光を透過させる材料から形成し、該結晶成
長用基板を介して前記光電陰極面に光入射させるように
した半導体光電面構造。(1) A semiconductor photocathode structure comprising a crystal growth substrate and a photocathode layer formed thereon by a crystal growth method and having a bandgap smaller than the bandgap of the crystal growth substrate, A semiconductor photocathode structure, wherein the crystal growth substrate is made of a material that transmits at least infrared light, and the light is made to enter the photocathode surface through the crystal growth substrate.
光を吸収する材料から形成されたことを特徴とする半導
体光電面構造。(2) The semiconductor photocathode structure according to claim 1, wherein the crystal growth substrate is made of a material that absorbs visible light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1207461A JPH0371528A (en) | 1989-08-10 | 1989-08-10 | Semiconductor photoelectric surface structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1207461A JPH0371528A (en) | 1989-08-10 | 1989-08-10 | Semiconductor photoelectric surface structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0371528A true JPH0371528A (en) | 1991-03-27 |
Family
ID=16540154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1207461A Pending JPH0371528A (en) | 1989-08-10 | 1989-08-10 | Semiconductor photoelectric surface structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0371528A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05266857A (en) * | 1991-12-20 | 1993-10-15 | Litton Syst Inc | Photocathode device, its manufacture, and image amplifier tube for night vision system applying photocathode device |
| JP2001105996A (en) * | 1999-10-04 | 2001-04-17 | Mitsuiya Kogyo Kk | Floor back cover for automobile |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49114869A (en) * | 1973-02-13 | 1974-11-01 |
-
1989
- 1989-08-10 JP JP1207461A patent/JPH0371528A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49114869A (en) * | 1973-02-13 | 1974-11-01 |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05266857A (en) * | 1991-12-20 | 1993-10-15 | Litton Syst Inc | Photocathode device, its manufacture, and image amplifier tube for night vision system applying photocathode device |
| JP2001105996A (en) * | 1999-10-04 | 2001-04-17 | Mitsuiya Kogyo Kk | Floor back cover for automobile |
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