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Transmission type photocathode and preparation method and application thereof

A photocathode and transmissive technology, which is applied in the direction of photoemission cathode, luminescent cathode manufacturing, electron multiplier cathode device, etc., can solve the problems that cannot meet the requirements of photocathode anti-reflection, anti-reflection effect is not obvious, weakened, etc.

Active Publication Date: 2020-09-04
SHAANXI SCI TECH UNIV +1
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  • Summary
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  • Description
  • Claims
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Problems solved by technology

[0004]In the above technical solution, the Si3N4 anti-reflection coating is only a layer with a thickness of about 100nm Correspondingly, the thin film layer has a good anti-reflection effect only in the narrow range of 100-200nm (for ≥600nm response band), while the short-wave response band has no obvious anti-reflection effect or even has a certain weakening, resulting in short-wave The wavelength band has high reflectivity, and the loss due to light reflection in the short-wavelength band reaches 5-20%, or even higher, especially for blue extended transmission cathodes with ultra-broadband, the light reflection loss in the 390-420nm band reaches 30% %above
In addition, for some photocathodes with specific narrow spectral response, such as GaAlAs photocathode, although a single Si3N4 anti-reflection coating can achieve light anti-reflection effect, but Due to the need for a sufficient thickness of Si3N4 anti-reflection coating to block the source of impurity pollution in the glass during the thermal bonding process, limiting Si3 The thickness of the N4 anti-reflection coating, so it cannot meet the anti-reflection requirements of the photocathode in a specific spectral band
Therefore, the loss of light reflection restricts the further improvement of the quantum effect of the current transmissive photocathode. How to further reduce the light reflectance of the entire response band and improve the absorptivity of the cathode is one of the inevitable ways to improve the current quantum efficiency.

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  • Transmission type photocathode and preparation method and application thereof
  • Transmission type photocathode and preparation method and application thereof
  • Transmission type photocathode and preparation method and application thereof

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preparation example Construction

[0053] The present invention also provides a method for preparing the transmissive photocathode described in the above technical solution, comprising the following steps:

[0054] Depositing an outer surface optical anti-reflection film on one side of the glass window to obtain a glass window deposited with an outer surface optical anti-reflection film;

[0055] After epitaxially growing a GaAs smooth layer, a barrier layer, an emission layer, a buffer layer and a protective layer on the GaAs substrate in sequence, the protective layer is removed by etching to expose the buffer layer;

[0056] Under vacuum conditions, use a mask plate to cover the part of the buffer layer to be deposited with an anti-reflection film on the inner surface, after depositing an adhesive film on the surface of the buffer layer, use a mask plate to cover the adhesive film, and deposit the inner surface. Surface anti-reflection film, obtain adhesive film / inner surface anti-reflection film, control th...

Embodiment 1

[0079] A kind of transmissive photocathode, the anti-reflection film on the outer surface, glass window, adhesive film / anti-reflection film on the inner surface, buffer layer, emission layer and active layer (structural relationship such as figure 1 shown);

[0080] Among them, the anti-reflection coating on the outer surface: TiO2 which is arranged sequentially from the glass window 2 layer (12.3nm), SiO 2 layer (33.5nm), TiO 2 layer (27nm), SiO 2 layer (13.5nm), TiO 2 layer (86.3nm), SiO 2 layer (18.3nm), TiO 2 layer (19nm) and MgF 2 layer (95nm);

[0081] Glass window: double-sided polished Corning 7056 borosilicate glass;

[0082] Adhesive film / inner surface anti-reflection coating: Adhesive film: Si installed sequentially from the buffer layer 3 N 4 film (170nm) and SiO 2 membrane;

[0083] Anti-reflection coating on the inner surface: Si in order from the buffer layer 3 N 4 layer (60nm), MgF 2 (71nm), Si 3 N 4 layer (7.3nm) and MgF 2 (91nm);

[0084] B...

Embodiment 2

[0099] A kind of transmissive photocathode, the anti-reflection film on the outer surface, glass window, adhesive film / anti-reflection film on the inner surface, buffer layer, emission layer and active layer (structural relationship such as figure 1 shown);

[0100] Among them, the anti-reflection coating on the outer surface: TiO2 which is arranged sequentially from the glass window 2 layer (13.3nm), SiO 2 layer (33.7nm), TiO 2 layer (27nm), SiO 2 layer (12nm), TiO 2 layer (79.5nm), SiO 2 layer (22nm), TiO 2 layer (17.3nm) and MgF 2 layer (99nm);

[0101] Glass window: 9741 transparent purple glass polished on both sides;

[0102] Adhesive film / inner surface anti-reflection coating: Adhesive film: Si installed sequentially from the buffer layer 3 N 4 film (270nm) and SiO 2 membrane;

[0103] Anti-reflection coating on the inner surface: starting from the buffer layer: Si 3 N 4 layer (62.5nm), MgF 2 (46.5nm), Si 3 N 4 layer (14.7nm) and MgF 2 (142.5nm);

[0...

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Abstract

The invention relates to the technical field of photocathodes, in particular to a transmission type photocathode and a preparation method and application thereof. According to the photocathode, through the arrangement of an outer surface antireflection film and an inner surface antireflection film, the light absorption rate of the cathode can be greatly improved, and the quantum efficiency of thecathode is improved. Meanwhile, the bonding film and the inner surface antireflection film are distinguished, the cathode can be divided into a central anti-reflection region through which signal light can pass and a peripheral bonding region through which the signal light does not need to pass, the light anti-reflection region of the signal light response region does not need to bear a bonding function, and the bonding region does not need to bear the anti-reflection function of the signal light, so that the stress of the anti-reflection film can be greatly released on the basis of realizingbonding, a series of adverse effects caused by bonding are eliminated, and the transmission type photocathode has higher spectral sensitivity in blue-green light and shorter wave bands; and the invention also provides a preparation method of the transmission type photocathode, and the preparation method realizes separation of a bonding function and an anti-reflection function, thereby reducing adverse factors of bonding.

Description

technical field [0001] The invention relates to the technical field of photocathode, in particular to a transmissive photocathode and its preparation method and application. Background technique [0002] The GaAs-based transmissive photocathode, represented by the negative electron affinity GaAs photocathode, is the core component of photoelectric conversion for vacuum detection and imaging devices such as low-light image intensifiers and photomultiplier tubes. It has high quantum efficiency, wide response band, With the advantages of small dark current, average electron energy and angular distribution, it has been widely used in photoelectric detection and imaging, high-energy physical electron sources and other fields. Especially in military applications, aerospace detection, and environmental detection, the low-light image intensifier with the transmissive GaAs photocathode as the core plays an important role. Quantum efficiency is one of the most important technical ind...

Claims

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Application Information

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IPC IPC(8): H01J1/34H01J40/06H01J43/08H01J31/50H01J9/12
CPCH01J1/34H01J40/06H01J43/08H01J31/50H01J9/12
Inventor 蔡志鹏张景文
Owner SHAANXI SCI TECH UNIV
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