Top > Search of International Patents > SPIN-POLARIZED HIGH BRIGHTNESS ELECTRON GENERATING PHOTOCATHODE AND METHOD FOR MANUFACTURING FOR SAME

SPIN-POLARIZED HIGH BRIGHTNESS ELECTRON GENERATING PHOTOCATHODE AND METHOD FOR MANUFACTURING FOR SAME

Foreign code F170009279
File No. (S2016-0566-N0)
Posted date Nov 7, 2017
Country WIPO
International application number 2017JP013496
International publication number WO 2017179440
Date of international filing Mar 30, 2017
Date of international publication Oct 19, 2017
Priority data
  • P2016-081955 (Apr 15, 2016) JP
Title SPIN-POLARIZED HIGH BRIGHTNESS ELECTRON GENERATING PHOTOCATHODE AND METHOD FOR MANUFACTURING FOR SAME
Abstract [Problem] The objective of the present invention is to provide a spin-polarized high brightness electron generating photocathode for backside illumination which has a simple construction, and to provide a method for manufacturing the same.
[Solution] A thin film of a single-crystal compound semiconductor having negative electron affinity (NEA) is caused to form on a single-crystal substrate having nanometer surface flatness. This spin-polarized high brightness electron generating photocathode can be manufactured by metal-organic vapor phase epitaxy.
Outline of related art and contending technology BACKGROUND ART
Is spin-polarized electrons in the present invention, the electron spin and the downward upward does not have the same ratio of the electron spin state electrons there. NEA property, the vacuum level than the conduction band energy of the conductive layer means a low state, this is, negative electron affinity or negative electron affinity of the called state. NEA and has, in the case where the spin-polarized electrons are generated and, alternatively, the spin-polarized electrons is not generated in some cases. Spin-polarized electrons and the generating ability, electrons located in the conduction band are moved to the vacuum level, the spin-polarized electrons have the ability to generate the term. High brightness electron generating substance is, to absorb light and generate electrons with high luminance can be referred to as a material. The air is removed, in order to make the desired amount of the chemical solution, the injection needle is directed upward, the air in the space disposed above the syringe plunger can be pushed toward to the bottom dead center, from the chemical solution and excess air in the syringe is extracted to perform the task. The photocathode of the present invention is to generate high brightness electron spin polarization, absorb light and generate a high brightness electron photocathode, in addition, polarization of the polarized light such as a laser absorbing the high-intensity spin-polarized electrons can be generated in the photocathode.
Conventional, spin-polarized electron generating device of the back-illuminated type according to the invention has been proposed (JP-1-4). Patent Document 1 is, as a main component on the substrate GaAs GaAs intermediate layer or buffer layer are stacked, a superlattice layer on a GaAs-GaAsP 10 mono-layers and, further on the thin film of GaAs (hereinafter, abbreviated as the active layer NEA.) Is formed by the spin-polarized electron generating device is disclosed. Is Patent Document 2, GaN and AlGaInN as a main component on a substrate an intermediate layer or buffer layer are stacked, on a GaAs-GaAsP superlattice layer 10 and mono-layers, such as NEA GaAs active layer is further formed on the spin-polarized electron generating device is disclosed. Patent Document 3 is, on the GaP substrate and the buffer at least the intermediate layer mainly composed of AlGaAsP layer are stacked, a superlattice layer on a GaAs-GaAsP and 10 mono-layers, such as NEA GaAs active layer is further formed on the spin-polarized electron generating device is disclosed. Patent Document 4 is, as a main component on the substrate GaAs InGaAs intermediate layer or buffer layer are stacked, a superlattice layer on a GaAs-GaAsP and 10 mono-layers, such as NEA GaAs active layer is further formed on the spin-polarized electron generating device is disclosed.
Of the conventional back-illuminated type of the spin-polarized electron generating device, the spin polarization of about 90% electrons are produced is possible, to convert light into electrons is very small and the quantum efficiency of the device (generally 0.4% or less) by, in making it difficult to generate high brightness electron (103 Acm-2 sr-1 of very low luminance) can be, such as NEA GaAs of the uppermost substrate and the active layer or intermediate layer between the buffer layer is always necessary to interpose the manufacturing steps can be very complex, light transmittance of the substrate used for the element to the absorption edge of the excitation light is limited by the narrow wavelength range, such as the problem to be improved for practical use.
However, an extremely high degree of spin-polarized to 90% or more while maintaining high quantum efficiency can be to generate high brightness electron, having a simple structure, can be used in a wide wavelength range of the excitation light, the spin polarization of the back-illuminated photocathode the electrons generated in the high brightness and a manufacturing method thereof, almost not known.
Scope of claims (In Japanese)[請求項1]
ナノメートルレベルの平坦な清浄表面を有し1.5eVから10eVの範囲にあるバンドギャップを有する単結晶基板と、該基板の上にエピタキシャル成長させた、該基板に対して選ばれた一つの、0.15eVから6.5eVの範囲にあるバンドギャップを有しかつNEA性を有する単結晶化合物半導体の薄膜と、からなるスピン偏極高輝度電子発生フォトカソードであって、前記単結晶基板の底面に1.5eVから10eVの範囲にある光が入射されたときに、前記単結晶化合物半導体の薄膜から電子線輝度が107Acm-2sr-1程度乃至それ以上の電子線が発生されることを特徴とするスピン偏極高輝度電子発生フォトカソード。
[請求項2]
ナノメートルレベルの平坦な清浄表面を有し1.5eVから10eVの範囲にあるバンドギャップを有する単結晶基板と、該基板の上にエピタキシャル成長させた、該基板に対して選ばれた一つの、0.15eVから6.5eVの範囲にあるバンドギャップを有しNEA性及びスピン偏極電子発生能を有する単結晶化合物半導体の薄膜と、からなるスピン偏極高輝度電子発生フォトカソードであって、前記単結晶基板の底面に1.5eVから10eVの範囲にある光が入射されたときに、前記単結晶基板の底面に1.5eVから10eVの範囲にある偏光レーザーが入射されたときに、前記単結晶化合物半導体の薄膜から電子線輝度が107Acm-2sr-1程度乃至それ以上の、且つ、スピン偏極度が90%以上程度乃至それ以上の電子線が発生されることを特徴とするスピン偏極高輝度電子発生フォトカソード。
[請求項3]
前記単結晶化合物半導体がGaAs系の単結晶化合物半導体であり、前記単結晶基板がZnS又はZnTeであることを特徴とする請求項1又は2に記載のスピン偏極高輝度電子発生フォトカソード。
[請求項4]
前記単結晶化合物半導体がGaAs系の単結晶化合物半導体であり、前記単結晶基板がZnSeであることを特徴とする請求項1又は2に記載のスピン偏極高輝度電子発生フォトカソード。
[請求項5]
前記単結晶化合物半導体がInSb系の単結晶化合物半導体であり、前記単結晶基板がMgTe、CdTe、CdMnTe及びCdZnTeの中から選ばれた一つであることを特徴とする請求項1又は2に記載のスピン偏極高輝度電子発生フォトカソード。
[請求項6]
前記単結晶化合物半導体がInN系の単結晶化合物半導体であり、前記単結晶基板が単結晶ダイヤモンド及び立方晶窒化硼素の中から選ばれた一つであることを特徴とする請求項1又は2に記載のスピン偏極高輝度電子発生フォトカソード。
[請求項7]
前記単結晶化合物半導体がGaN系の単結晶化合物半導体であり、前記単結晶基板がZnO及び六方晶窒化ホウ素の中から選ばれた一つであることを特徴とする請求項1又は2に記載のスピン偏極高輝度電子発生フォトカソード。
[請求項8]
前記単結晶化合物半導体がCdS系の単結晶化合物半導体であり、前記単結晶基板がGaNであることを特徴とする請求項1又は2に記載のスピン偏極高輝度電子発生フォトカソード。
[請求項9]
前記単結晶化合物半導体が50nm~500nmの厚みであることを特徴とする請求項1~8のいずれか1項に記載のスピン偏極高輝度電子発生フォトカソード。
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • HIGH ENERGY ACCELERATOR RESEARCH ORGANIZATION
  • Inventor
  • KIN Shuko
  • TAKEDA Yoshikazu
  • YAMAMOTO Masahiro
  • KAMIYA Yukihide
IPC(International Patent Classification)
Specified countries National States: AE AG AL AM AO AT AU AZ BA BB BG BH BN BR BW BY BZ CA CH CL CN CO CR CU CZ DE DJ DK DM DO DZ EC EE EG ES FI GB GD GE GH GM GT HN HR HU ID IL IN IR IS KE KG KH KN KP KR KW KZ LA LC LK LR LS LU LY MA MD ME MG MK MN MW MX MY MZ NA NG NI NO NZ OM PA PE PG PH PL PT QA RO RS RU RW SA SC SD SE SG SK SL SM ST SV SY TH TJ TM TN TR TT TZ UA UG US UZ VC VN ZA ZM ZW
ARIPO: BW GH GM KE LR LS MW MZ NA RW SD SL SZ TZ UG ZM ZW
EAPO: AM AZ BY KG KZ RU TJ TM
EPO: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
OAPI: BF BJ CF CG CI CM GA GN GQ GW KM ML MR NE SN ST TD TG
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