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An Activation Method to Improve the Quantum Efficiency and Lifetime of Gaas Photocathodes

A photocathode and quantum efficiency technology, applied in the manufacture of light-emitting cathodes, can solve unsatisfactory problems

Active Publication Date: 2020-10-20
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the GaAs photocathode obtained by using the tungsten-halogen lamp as the activation method under the illumination condition still has a lot of room for improvement in terms of quantum effect and stability, especially in terms of cathode life, which is not satisfactory.

Method used

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  • An Activation Method to Improve the Quantum Efficiency and Lifetime of Gaas Photocathodes
  • An Activation Method to Improve the Quantum Efficiency and Lifetime of Gaas Photocathodes
  • An Activation Method to Improve the Quantum Efficiency and Lifetime of Gaas Photocathodes

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Embodiment

[0029] Before cesium oxygen activation, we chemically clean and high-temperature purify the GaAs photocathode material.

[0030] The step of chemical cleaning is to first put the sample into a certain amount of CCl 4 Then place the beaker in an ultrasonic cleaner to vibrate for 5 minutes, then take out the sample, and then wash the sample in acetone, ethanol, and deionized water in the same way. Then put the sample into the HF solution and let it stand for cleaning for 5 minutes. Finally, rinse the sample repeatedly with deionized water and dry it.

[0031] The step of high-temperature purification is to send the sample to the heating position of the activation system for heating. The heating temperature is 650°C and the heating time is 10 minutes. During the heating process, the vacuum degree of the system should not be lower than 1×10 -7 Pa, so as to avoid secondary pollution of the sample by vacuum residual gas when cooling down. After the heating is over, the cesium oxyg...

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Abstract

The invention discloses an activation method of improving quantum efficiency and service life of a GaAs photocathode, namely, in an ultrahigh vacuum activation system, a monochromatic light source with wavelength of 532nm is used to substitute the conventional halogen tungsten lamp light source to perform activation. The method comprises the following activation steps: 1, performing chemical cleaning for a to-be-activated GaAs sample; 2, performing high temperature purification for the sample subjected to chemical cleaning; 3, irradiating on a cathode surface through the monochromatic light source with wavelength of 532nm, and activating the sample through a technology where a Cs source is continuous and an oxygen source is intermittent. The GaAs photocathode obtained through the method above is improved greatly in quantum effect and stability.

Description

technical field [0001] The invention relates to an activation method using monochromatic light in the process of preparing negative electron affinity semiconductor photoelectric emission materials, in particular to an activation method capable of improving the quantum effect and lifespan of GaAs photocathode. Background technique [0002] Gallium arsenide (GaAs) photocathode, as a kind of negative electron affinity photocathode, can convert the weak light signal which is difficult to be distinguished by naked eyes into electrical signal, and it has good photoelectric performance and broad prospect. In order to obtain a high quantum effect and a long life, it has extremely high requirements on the vacuum degree of the preparation method and the production equipment and the degree of surface purification. For now, the stability of the cathode still needs to be further improved, that is, to slow down the decay rate of the cathode quantum efficiency over time to the greatest ext...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01J9/12
CPCH01J9/12
Inventor 张益军张景智冯琤张翔钱芸生张俊举戴庆鑫
Owner NANJING UNIV OF SCI & TECH
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