WO1999016098A1 - Surface photoelectrique de semi-conducteur - Google Patents

Surface photoelectrique de semi-conducteur Download PDF

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Publication number
WO1999016098A1
WO1999016098A1 PCT/JP1998/004119 JP9804119W WO9916098A1 WO 1999016098 A1 WO1999016098 A1 WO 1999016098A1 JP 9804119 W JP9804119 W JP 9804119W WO 9916098 A1 WO9916098 A1 WO 9916098A1
Authority
WO
WIPO (PCT)
Prior art keywords
active layer
layer
semiconductor photocathode
photocathode
semiconductor
Prior art date
Application number
PCT/JP1998/004119
Other languages
English (en)
Japanese (ja)
Inventor
Tokuaki Nihashi
Original Assignee
Hamamatsu Photonics K.K.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hamamatsu Photonics K.K. filed Critical Hamamatsu Photonics K.K.
Priority to DE69807103T priority Critical patent/DE69807103T2/de
Priority to AU90029/98A priority patent/AU9002998A/en
Priority to EP98941849A priority patent/EP1024513B1/fr
Publication of WO1999016098A1 publication Critical patent/WO1999016098A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J40/00—Photoelectric discharge tubes not involving the ionisation of a gas
    • H01J40/02—Details
    • H01J40/04—Electrodes
    • H01J40/06—Photo-emissive cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/34—Photo-emissive cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/34—Photoemissive electrodes
    • H01J2201/342—Cathodes
    • H01J2201/3421—Composition of the emitting surface
    • H01J2201/3423—Semiconductors, e.g. GaAs, NEA emitters

Definitions

  • the present invention relates to a semiconductor photocathode that emits photoelectrons into a vacuum upon incidence of photons, in particular a III-V semiconductor photocathode.
  • a semiconductor photocathode used for a photomultiplier tube has a high photoelectron emission efficiency.
  • One such semiconductor photocathode is disclosed in US Pat. No. 3,387,161.
  • This semiconductor photocathode has an active layer obtained by activating the surface of a p-type semiconductor having a doping concentration of 1 ⁇ 10 18 cm 3 or more and 1 ⁇ 10 19 cm ′′ 3 or less with an alkali metal. With this configuration, downward energy band bending is formed on the vacuum emission side surface of the photocathode, which lowers the vacuum level barrier on the surface to facilitate the escape of photoelectrons and separates from the vacuum emission side surface. Even photoelectrons generated inside the active layer are more likely to reach the emission side surface because the diffusion length can be increased without lowering the electron emission probability.
  • the doping concentration is low. This is because the lower the doping concentration, the more the decrease in crystallinity can be suppressed.
  • the dopant concentration is low, the diffusion length can be increased, but the probability of electron emission decreases, resulting in a decrease in quantum efficiency. For this reason, conventionally, It was difficult to further reduce the concentration.
  • an object of the present invention is to provide a semiconductor photocathode having a low doping concentration and a high quantum efficiency.
  • the semiconductor photocathode of the present invention is a semiconductor photocathode which emits photoelectrons into a vacuum in response to incident photons, wherein the surface on the photoelectron emission side is a P-type doped III activated with alkali metal or alkali metal oxide.
  • An active layer comprising a Group V compound semiconductor is provided, and the surface doping concentration on the photoelectron emission side of the active layer is 1 ⁇ 10 17 cm 3 or less.
  • the diffusion length increases.
  • the crystal is good, the probability of electrons reaching the emission side surface is high, the deterioration of the electron emission probability can be prevented, and the quantum efficiency can be kept high.
  • the energy band gap of the active layer is preferably at least twice the work function of the alkali metal or alkali metal oxide of the surface layer. In this case, electrons are easily emitted from the surface.
  • An electron supply layer may be provided on a side different from the photoelectron emission side of the active layer.
  • the doping concentration of the active layer may be 1 ⁇ 10 17 cm 3 or less in the vicinity of the photoelectron emission surface and 1 ⁇ 10 to 1 ⁇ 10 cm ′′ ′ on the back side.
  • the doping concentration of the active layer may be gradually increased from the vicinity of the photoelectron emitting surface toward the back, and the doping concentration at the deepest portion on the back side may be 1 ⁇ 10 to 1 ⁇ 10 cm.
  • the diffusion length is further increased, and the electric field inside the diffusion layer is configured to move the electrons toward the emission surface side, so that the probability of the electrons reaching the emission surface is improved.
  • the thickness of the region having a doping concentration of 1 ⁇ 10 18 to 1 ⁇ 10 19 cm ′ 3 on the back side of the active layer is several nm or less.
  • the amount of photoelectrons that migrate to the side opposite to the emission-side surface and disappear is suppressed. For this reason, Applicable to over-type photocathode structure.
  • a Schottky electrode formed on the surface of the active layer may be provided, and an external bias may be applied to the active layer. According to this, the photoelectrons generated inside the active layer due to the external bias are efficiently guided to the emission side surface.
  • FIG. 1 is a schematic diagram of a phototube using the photocathode of the present invention.
  • FIG. 2 is a diagram showing a dopant concentration distribution of the active layer on the photocathode of FIG.
  • FIG. 3 is a diagram comparing wavelength characteristics of the photoelectric surface of the present invention and a conventional product.
  • FIG. 4 is a graph showing the relationship between the dopant concentration and the quantum efficiency.
  • FIG. 5 is a diagram showing an example of the dopant concentration distribution of the active layer of the photocathode of the present invention.
  • FIG. 6 is a diagram showing another example of the dopant concentration distribution of the active layer of the photocathode of the present invention.
  • FIG. 7 is a diagram showing still another example of the dopant concentration distribution of the active layer of the photocathode of the present invention.
  • FIG. 1 is a schematic diagram of a transmission type phototube using a semiconductor photocathode according to the present invention.
  • the phototube 10 is configured such that a photocathode 30 and an anode 40 using a semiconductor photocathode according to the present invention are accommodated in a sealed container 20 whose inside is evacuated.
  • This vacuum container
  • the photocathode 30 is supported by metal lead pins 51 via a metal support plate 31 having a hole at the center and a metal support base 50.
  • the anode 40 is a metal electrode formed in a rectangular frame shape, and is supported by a metal lead pin 52.
  • the lead pins 51 and 52 penetrate the bottom of the vacuum vessel 20 and are connected to external power sources, respectively, and apply a voltage higher than that of the photocathode 30 to the anode 40.
  • the photocathode 30 is a substrate formed of sapphire on a rectangular frame-shaped metal support plate 31.
  • a matching layer 33, an active layer 34, and a surface layer 35 are sequentially laminated thereon.
  • the matching layer 33 is made of, for example, amorphous A 1 N grown on the substrate 32 by epitaxial growth.
  • the matching layer 33 has a thickness of about 10 nm, and is lattice-matched with the active layer 34 to allow the active layer 34 to grow well. Further, it is provided for the purpose of preventing backward movement of photoelectrons generated in the active layer 34.
  • the active layer 34 is formed from p-type GaN epitaxially grown on the matching layer 33.
  • the thickness of the active layer 34 is 100 nm or more, and Mg or Zn is doped as a p-type dopant. Its concentration distribution is as shown in Fig. 2.It has a first layer with a thickness of lOOnm near the surface and a second layer with a thickness of lnm formed at least deeper than the light incident surface.
  • the dopant concentration near the surface is 1 ⁇ 10 16 cm 3
  • the concentration increases toward the second layer
  • the concentration at the boundary with the second layer is 5 ⁇ 10 17 cm 3
  • the dopant concentration in the second layer is 1 ⁇ 10 18 cm 3 higher than in the first layer.
  • the growth of the matching layer 33 and the active layer 34 is performed by MOCVD, MBE, HWE, etc. Various crystal growth methods can be used.
  • a surface layer 35 made of an alkali metal or an oxide thereof, for example, Cs or Cs0 is formed by vapor deposition. This surface layer 35 is formed as a monoatomic layer.
  • the energy band gap of the vacuum discharge of the surface layer 35 when C s is used as the metal is 1.4 eV, and when C s O is used, the energy band gap is 0.9 eV.
  • the band gap is less than half of 3.4 eV.
  • the operation of the photoelectric tube will be described.
  • the incident light passes through the hole of the metal support plate 31, passes through the substrate 32, the matching layer 33, and enters the active layer 34.
  • Photons are absorbed mainly in the first layer of the active layer 34 to generate photoelectrons.
  • the distribution of the band gap energy in the active layer 34 substantially corresponds to the dopant concentration.
  • the photoelectrons generated in the first layer move in the first layer so as to slide down the slope and reach the surface layer 35, and have a large band gap with the surface layer 35. Is extremely thin, so it is easily released into a vacuum.
  • the emitted photoelectrons reach the anode 40 by an electric field between the photocathode 30 and the anode 40 and are detected as a current.
  • the present inventor compared the wavelength characteristics of the conventional photocathode and the photocathode of the present invention shown in FIG. The results are shown in comparison with FIG.
  • a comparison was made with a conventional product in which the active layer was one layer and the dopant concentration was 1 ⁇ 10 18 cm 3 .
  • the broken line shows the wavelength characteristics of the quantum efficiency of the photocathode of the present invention, and the straight line shows the wavelength characteristics of the quantum efficiency.
  • the product of the present invention has a higher quantum efficiency at a wavelength of 350 nm or less than the conventional product, has a low quantum efficiency at a wavelength of 400 ⁇ or more, improves sharp cut properties, and improves characteristics in a low wavelength region. It was confirmed that. This is thought to be due to the fact that, as the diffusion length increases, the probability of photoelectrons reaching the surface increases due to the improvement in crystallinity, thereby improving the photoelectron emission efficiency from the surface.
  • Figure 4 shows various prototypes with different dopant concentrations in the active layer.
  • 5 is a graph comparing quantum efficiency at 254 nm. The quantum efficiency varies considerably depending on the prototype, but the overall high dopant concentration (1 ⁇ 18 to 1X)
  • the concentration distribution of the active layer 34 may be composed of a first layer and a second layer as shown in FIG. 5 in addition to that shown in FIG. 2, and the concentration of each may be changed stepwise. . With this configuration, photoelectrons generated by photons incident from the opposite side of the emission surface can be effectively guided to the emission side.
  • the photocathode of the present invention can be applied to a reflection photocathode which emits photoelectrons on the same side as the incident direction of photons.
  • the matching layer 33 may be formed of, for example, amorphous A 1 N or GaN epitaxially grown on the substrate 32.
  • FIGS. 6 and 7 show the concentration distribution of the active layer on the reflection type photoelectric surface corresponding to the transmission type photoelectric surface of FIGS. 2 and 5, respectively. In either case, photoelectrons generated in the high dopant concentration layer can be efficiently guided to the emission side surface.
  • Control of these dopant concentrations can be easily set by controlling the supply of the dopant material. Although it is preferable to provide a high-concentration region in a portion away from the emission surface, it is not essential and may not be provided. Alternatively, by applying an external bias voltage to the active layer, the internal energy-bandgap level may be graded to force photoelectrons to the emission surface. In this case, the internal dopant concentration may be uniform, or the predetermined distribution may be provided as described above.
  • G a N As the active layer
  • G a, In, A l, B, etc. are used as group III materials
  • N, P, As, etc. are used as V group materials. Can be used.
  • alkali metal of the surface layer Cs, Cs0, etc. can be used. You.
  • the active layer having a low dopant concentration stabilizes the crystallinity and increases the diffusion length, so that the photocathode having high quantum efficiency and improved sharp cut property can be obtained. can get.
  • the photoelectric surface according to the present invention can be applied not only to a photoelectric tube but also to a photoelectric surface performing various photoelectric conversions.

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  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)

Abstract

L'invention porte sur un phototube (10) comprenant une photocathode (30) à surface photoélectrique. Dans une enceinte fermée hermétiquement à l'intérieur de laquelle on a fait le vide, la cathode photoélectrique (30) et une anode (40) sont placées à l'opposé l'une de l'autre. Des tensions sont appliquées sur celles-ci au moyen de broches (51) et (52) conductrices. La photocathode (30) comprend une plaque (31) de support métallique à laquelle est fixée une plaque (32) en saphir sur laquelle sont formées une couche d'adaptation a-AlN (33), une couche active Ga-N de type p (34) et une couche superficielle (35) CsO. La couche active (34) a une concentration en impuretés qui augmente de 1 x 1016 cm-3 en surface, et jusqu'à 5 x 1017 cm-3 à une profondeur de 100 nm. La concentration en impuretés est de 1 x 1018 cm-3 uniquement au niveau de la région la plus profonde, sur une épaisseur de plusieurs nanomètres. La cristallinité de la couche active (34) est ainsi améliorée, la longueur de diffusion augmentée, ce qui permet d'obtenir un meilleur rendement quantique et une meilleure qualité de coupure franche.
PCT/JP1998/004119 1997-09-24 1998-09-11 Surface photoelectrique de semi-conducteur WO1999016098A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE69807103T DE69807103T2 (de) 1997-09-24 1998-09-11 Halbleitende photoelektrische oberfläche
AU90029/98A AU9002998A (en) 1997-09-24 1998-09-11 Semiconductor photoelectric surface
EP98941849A EP1024513B1 (fr) 1997-09-24 1998-09-11 Surface photoelectrique de semi-conducteur

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP9/258837 1997-09-24
JP25883797A JPH1196896A (ja) 1997-09-24 1997-09-24 半導体光電面

Publications (1)

Publication Number Publication Date
WO1999016098A1 true WO1999016098A1 (fr) 1999-04-01

Family

ID=17325721

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1998/004119 WO1999016098A1 (fr) 1997-09-24 1998-09-11 Surface photoelectrique de semi-conducteur

Country Status (5)

Country Link
EP (1) EP1024513B1 (fr)
JP (1) JPH1196896A (fr)
AU (1) AU9002998A (fr)
DE (1) DE69807103T2 (fr)
WO (1) WO1999016098A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11313718B2 (en) 2017-05-30 2022-04-26 Carrier Corporation Semiconductor film and phototube light detector

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2249877C2 (ru) * 2003-04-29 2005-04-10 Бенеманская Галина Вадимовна Устройство для получения фотоэлектронной эмиссии в вакуум
JP2006302843A (ja) * 2005-04-25 2006-11-02 Hamamatsu Photonics Kk 光電面及びそれを備える電子管
RU2454750C2 (ru) * 2010-08-02 2012-06-27 Учреждение Российской академии наук Физико-технический институт им. А.Ф. Иоффе РАН Фотокатод
CN102087937A (zh) * 2011-01-07 2011-06-08 南京理工大学 指数掺杂GaN紫外光电阴极材料结构及其制备方法
US9478402B2 (en) * 2013-04-01 2016-10-25 Kla-Tencor Corporation Photomultiplier tube, image sensor, and an inspection system using a PMT or image sensor
CN105428183B (zh) * 2015-11-17 2017-08-04 南京理工大学 一种反射式NEA GaN纳米线阵列光电阴极及制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49114869A (fr) * 1973-02-13 1974-11-01
JPS5335434B1 (fr) * 1970-01-19 1978-09-27
JPH021327B2 (fr) * 1980-06-02 1990-01-11 Intaanashonaru Bijinesu Mashiinzu Corp
JPH06223709A (ja) * 1993-01-25 1994-08-12 Katsumi Kishino 偏極電子線発生素子
JPH0750587B2 (ja) * 1991-02-25 1995-05-31 浜松ホトニクス株式会社 半導体光電子放出体

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL147572B (nl) * 1964-12-02 1975-10-15 Philips Nv Elektrische ontladingsbuis met een fotokathode.
US3644770A (en) * 1968-01-18 1972-02-22 Varian Associates Photoemitter having a p-type semiconductive substrate overlaid with cesium and n-type cesium oxide layers
FR2507386A1 (fr) * 1981-06-03 1982-12-10 Labo Electronique Physique Dispositif semi-conducteur, emetteur d'electrons, dont la couche active possede un gradient de dopage
US5047821A (en) * 1990-03-15 1991-09-10 Intevac, Inc. Transferred electron III-V semiconductor photocathode

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5335434B1 (fr) * 1970-01-19 1978-09-27
JPS49114869A (fr) * 1973-02-13 1974-11-01
JPH021327B2 (fr) * 1980-06-02 1990-01-11 Intaanashonaru Bijinesu Mashiinzu Corp
JPH0750587B2 (ja) * 1991-02-25 1995-05-31 浜松ホトニクス株式会社 半導体光電子放出体
JPH06223709A (ja) * 1993-01-25 1994-08-12 Katsumi Kishino 偏極電子線発生素子

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1024513A4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11313718B2 (en) 2017-05-30 2022-04-26 Carrier Corporation Semiconductor film and phototube light detector

Also Published As

Publication number Publication date
EP1024513B1 (fr) 2002-08-07
DE69807103T2 (de) 2003-01-23
DE69807103D1 (de) 2002-09-12
AU9002998A (en) 1999-04-12
EP1024513A1 (fr) 2000-08-02
EP1024513A4 (fr) 2000-09-20
JPH1196896A (ja) 1999-04-09

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