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Variable-component variable-doping reflective Al<x>Ga<1-x>As/GaAs photocathode and preparation method thereof

A photocathode and variable doping technology, which is used in the manufacture of light-emitting cathodes, image conversion/image amplifier tubes, cathode ray tubes/electron beam tubes, etc. Efficiency, the effect of improving transport capacity

Inactive Publication Date: 2020-02-07
NANJING INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method has the following problems: it can only improve the quantum efficiency of the AlGaAs photocathode in the band around 532nm; the buffer layer of this patent uses a Bragg mirror structure combined with an AlAs / GaAs structure, which changes the photocathode. Absorption characteristics, and then change the reflectivity of the photocathode, the volatility of the absorptivity curve, so that the absorptivity of the photocathode to photons is improved in some bands, but the absorptivity may decrease in other bands, by adjusting the appropriate Bragg reflection Mirror structure to achieve improved quantum efficiency in the 532nm band

Method used

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  • Variable-component variable-doping reflective Al&lt;x&gt;Ga&lt;1-x&gt;As/GaAs photocathode and preparation method thereof
  • Variable-component variable-doping reflective Al&lt;x&gt;Ga&lt;1-x&gt;As/GaAs photocathode and preparation method thereof
  • Variable-component variable-doping reflective Al&lt;x&gt;Ga&lt;1-x&gt;As/GaAs photocathode and preparation method thereof

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preparation example Construction

[0035] A variable composition variable doping reflective Al x Ga 1-x The preparation method of As / GaAs photocathode comprises the following steps:

[0036] Step 1: growing a GaAs transition layer on the GaAs substrate.

[0037] Step 2: Then grow Al composition Al on the GaAs transition layer x Ga 1-x As buffer layer.

[0038] Step 3: Change Al composition Al x Ga 1-x The As buffer layer is sequentially grown into individual unit layers of the exponentially doped GaAs emitter layer.

[0039] Step 4: Chemically clean the surface of the variable-composition variable-doped GaAs photocathode generated in step 3, and then send it to an ultra-high vacuum system for high-temperature heating, so that the surface of the GaAs photocathode is clean at the atomic level.

[0040] Step 5: Through the ultra-high vacuum activation process, the Cs and O 2 The alternating adsorption of Cs / O active layer is formed, and the high quantum efficiency variable composition variable doping refle...

specific Embodiment

[0044] Such as figure 2 As shown, the variable composition variable doping reflective Al made by the method of the present invention x Ga 1-x Schematic diagram of the As / GaAs photocathode structure. The cathode consists of a p-type GaAs transition layer with a thickness of 50nm from bottom to top, and a doping concentration of 1.0×10 19 cm -3 ; Thickness of 1000nm p-type variable Al component Al x Ga 1-x As buffer layer, the doping concentration is 1.0×10 19 cm -3 , the Al composition gradually changes from 0.9 to 0 from the rear interface to the emission layer interface; and the p-type index-doped GaAs emission layer with a total thickness of 200nm, the emission layer is a layered structure of 4 units, and the thickness of each unit is 50nm, the doping concentration from the rear interface to the emission surface is 1.0×10 19 cm -3 , 5.0×10 18 cm -3 , 2.5×10 18 cm -3 , 1.0×10 18 cm -3 .

[0045] The variable composition variable doping reflective Al x Ga 1-...

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Abstract

The invention relates to a variable-component variable-doping reflective Al<x>Ga<1-x>As / GaAs photocathode and a preparation method thereof. The cathode is composed of an n-type GaAs substrate, a p-type GaAs transition layer, a p-type variable-Al-component Al<x>Ga<1-x>As buffer layer and a p-type exponentially doped GaAs emission layer from bottom to top. The Al component of the p-type variable-Al-component Al<x>Ga<1-x>As buffer layer changes from 0.9 to 0 from the rear interface at the bottom to the top, and a uniform doping mode is adopted. The p-type exponentially doped GaAs emission layer is of a layered structure with four or more units, and the doping concentration adopts exponentially reduced concentration distribution from 10*10<19>cm<-3> of the unit layer at the rear interface to 1.0*10<18>cm<-3> of the unit layer on the emission surface. According to the invention, the transport capacity of photoelectrons in the cathode body can be improved, and the quantum efficiency of the GaAs photoelectric cathode can be improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of semiconductor photoelectric emission materials, in particular to a variable composition variable doping reflective Al x Ga 1-x As / GaAs photocathode and its preparation method. Background technique [0002] Due to the advantages of high quantum efficiency, small dark current, concentrated energy distribution of emitted electrons, good long-wave response, and high spin polarizability, III-V GaAs photocathode has become a popular choice for manufacturing various optoelectronic devices such as image intensifiers and polarized electron sources. , solar cells, etc. the best material. With the development of material growth technology and in order to improve device performance, many studies based on energy band engineering have been done to improve spectral characteristics. Several different models and structures have been proposed in recent years. [0003] Low-light image intensifier is the t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01J9/12H01J29/04H01J31/50
CPCH01J9/12H01J29/04H01J31/503
Inventor 冯琤刘健张益军宋宇飞赵静杨会军刘扬蒋姝
Owner NANJING INST OF TECH
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