Hamamatsu-photonics K.k.

Masami Yamada

Toru Hirohata

Minoru Niigaki

Tomoko Suzuki

Tuneo Ihara

Hirofumi Kan

Katsuyuki Kinoshita

Yasuharu Negi

Norio Asakura

Tomoko Mochizuki

Kimitsugu Nakamura

Yoshihiko Mizushima

Tomihiko Kuroyanagi

Minoru Nigaki

The invention relates to a photocathode having a structure that permits a decrease in the radiant sensitivity at low temperatures is suppressed so that the S/N ratio is improved. In the photocathode, a light absorbing layer is formed on the upper layer of a substrate. An electron emitting layer is formed on the upper layer of the light absorbing layer. A contact layer having a striped-shape is formed on the upper layer of the electron emitting layer. A surface electrode composed of metal is formed on the surface of the contact layer. The interval between bars in the contact layer is adjusted so as to become 0.2 &#x3bc;m or more but 2 &#x3bc;m or less.

Photocathode

The present invention is to provide a method of using a photocathode including a laminated heterostructure of Group III-V semiconductors, which is constituted by a p-type light-absorbing layer formed on a p-type substrate and a p-type electron-emitting layer formed on the light-absorbing layer, a first electrode formed to have a rectifying function with respect to the electron-emitting layer, and a second electrode formed in ohmic contact with the substrate, wherein a voltage necessary and sufficient to form a potential gradient throughout the light-absorbing layer is applied between the first electrode and the second electrode, thereby accelerating photoelectrons excited in the light-absorbing layer which absorbs external incident light on the basis of an electric field formed in the light-absorbing layer and the electron-emitting layer and emitting the photoelectrons from the electron-emitting layer. The accelerated electrons largely decrease differences in transit time until reaching the emission surface of the electron-emitting layer as compared to diffused electrons. Therefore, the response speed of the photocathode for detecting external incident light is increased.

Method of using photocathode and method of using electron tube

This invention relates to a transmission type electron multiplier having a high secondary electron generation efficiency and having the structure capable of detecting positions of incidence of detected light, and also to an electron tube provided therewith. The electron tube comprises a closed container, an electron source, housed in the closed container, for emitting electrons into the closed container, an anode disposed so as to face the electron source, and a transmission type electron multiplier disposed between the electron source and the anode. Particularly, the transmission type electron multiplier comprises a thin film of diamond or a material containing a principal component of diamond, and a reinforcing member for reinforcing the thin film, the reinforcing member having an aperture for exposing a part of the thin film.

Transmission type electron multiplier and electron tube provided

A photocathode includes a first layer of polycrystalline diamond or a material mainly composed of polycrystalline diamond. The first layer of polycrystalline diamond may be terminated with hydrogen, or oxygen, and a second layer of an alkali metal or compound of an alkali metal, may be provided on the first layer of polycrystalline diamond whose surface is terminated with hydrogen or oxygen. The photocathode can be use for both reflection and transmission electron tubes and can yield a quantum efficiency higher than that in a monocrystal diamond thin film.

Electron tube with polycrystalline diamond photocathode

The present invention relates to an electron tube having a configuration which can maintain its operating stability for a long period of time. The electron tube comprises, at least, a field emitter which is made of diamond or a material mainly composed of diamond and has a surface terminated with hydrogen, and a sealed envelope for accommodating the diamond field emitter. Due to the hydrogen termination, the electron affinity of the diamond field emitter is set to a negative state. Also, hydrogen is enclosed within the sealed envelope. Due to this configuration, the hydrogen-terminated state of the diamond field emitter surface is stabilized, and the electron affinity of the diamond emitter is restrained from changing for a long period of time.

Electron tube having a diamond field emitter

The present invention provides a photoemission device excellent in quantum efficiency of photoelectric conversion, a high-sensitive electron tube employing it, and a high-sensitive photodetecting apparatus. A photoemission device of the present invention is arranged to have a photon absorbing layer for absorbing incident photons to excite photoelectrons, an insulator layer layered on one surface of the photon absorbing layer, a lead electrode layered on the insulator layer, and a contact formed on the other surface of the photon absorbing layer to apply a predetermined polarity voltage between the lead electrode and the other surface of the photon absorbing layer, whereby the photoelectrons excited by the incident photons entering the photon absorbing layer and moving toward the one side are made to be emitted by an electric field formed between the lead electrode and the one surface by the predetermined polarity voltage.

Photoemitter electron tube, and photodetector

A photoelectric emission surface which is excellent in stability and reproducibility of photoelectric conversion characteristics and has a structure capable of obtaining a high photosensitivity is provided. A predetermined voltage is applied between an upper surface electrode and a lower surface electrode by a battery. Upon application of this voltage, a p-n junction formed between a contact layer and an electron emission layer is reversely biased. A depletion layer extends from the p-n junction into the photoelectric emission surface, and an electric field is formed in the electron emission layer and a light absorbing layer in a direction for accelerating photoelectrons. When incident light is absorbed in the light absorbing layer to excite photoelectrons, the photoelectrons are accelerated by the electric field toward the emission surface. The photoelectrons obtain an energy upon this electric field acceleration, and are transited, in the electron emission layer, to a conduction band at a higher energy level, and emitted into a vacuum.

Photomultiplier having a photocathode comprised of semiconductor material

A photoelectric emission surface which is excellent in stability and reproducibility of photoelectric conversion characteristics and has a structure capable of obtaining a high photosensitivity is provided. A predetermined voltage is applied between an upper surface electrode and a lower surface electrode by a battery. Upon application of this voltage, a p-n junction formed between a contact layer and an electron emission layer is reversely biased. A depletion layer extends from the p-n junction into the photoelectric emission surface, and an electric field is formed in the electron emission layer and a light absorbing layer in a direction for accelerating photoelectrons. When incident light is absorbed in the light absorbing layer to excite photoelectrons, the photoelectrons are accelerated by the electric field toward the emission surface. The photoelectrons obtain an energy upon this electric field acceleration, and are transitioned, in the electron emission layer, to a conduction band at a higher energy level, and emitted into a vacuum.

Photomultiplier having a photocathode comprised of a compound

Photoemitter electron tube and photodetector

There is disclosed a photocathode comprising:

Photocathode capable of detecting position of incident light in one or

This invention relates to a semiconductor photo-electron-emitting device for emitting photoelectrons excited from the valence band to the conduction band by incident photons on a semiconductor layer. The device includes a Schottky electrode formed on the emitting surface on a surface of the semiconductor layer, and a conductor layer formed on a surface opposite to the emitting surface. A set bias voltage is applied between the Schottky electrode and the conductor layer to accelerate photoelectrons generated by the excitation of incident photons to the emitting surface and to transfer the accelerated photoelectrons from an energy band of a smaller effective mass to an energy band of a larger effective mass.

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Hamamatsu, Japan

Masami Yamada