The effect of surface cleaning on quantum efficiency in AlGaN photocathode

Hao, Gazi; Zhang, Yijun; Jin, Muchun; Feng, Cheng; Chen, Xinlong; Chang, Benkang

doi:10.1016/j.apsusc.2014.11.001

Cited by 25 publications

(2 citation statements)

References 19 publications

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“…Various semiconductor photocathode fabrication systems mainly for Cs 2 Te [26,[28][29][30][31][32], bialkali (K 2 CsSb, K 2 NaSb) [33][34][35][36][37] and GaAs [14,[38][39][40], have been built in different institutes in China and the growth procedures and characterizations of semiconductor photocathodes have been investigated.…”

Section: Methodsmentioning

confidence: 99%

Overview of the Semiconductor Photocathode Research in China

Xie

2021

Micromachines

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With the growing demand from scientific projects such as the X-ray free electron laser (XFEL), ultrafast electron diffraction/microscopy (UED/UEM) and electron ion collider (EIC), the semiconductor photocathode, which is a key technique for a high brightness electron source, has been widely studied in China. Several fabrication systems have been designed and constructed in different institutes and the vacuum of most systems is in the low 10−8 Pa level to grow a high QE and long lifetime photocathode. The QE, dark lifetime/bunch lifetime, spectral response and QE map of photocathodes with different kinds of materials, such as bialkali (K2CsSb, K2NaSb, etc.), Cs2Te and GaAs, have been investigated. These photocathodes will be used to deliver electron beams in a high voltage DC gun, a normal conducting RF gun, and an SRF gun. The emission physics of the semiconductor photocathode and intrinsic emittance reduction are also studied.

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Section: Methodsmentioning

confidence: 99%

Overview of the Semiconductor Photocathode Research in China

Xie

2021

Micromachines

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“…The negative electron affinityphotocathodes with high quantum efficiency and extended working life have the potential to be applied to the core components in next‐generation electron accelerators and UV detectors . III‐nitride has wide bandgap adjustment from deep UV to near‐infrared, making AlGaN photocathodes an excellent choice . Initially, in order to solve the lattice mismatch problem between the AlGaN emission layer and the AlN buffer layer, which causes the photoelectrons to recombine and shortens the electron lifetime, a buffer layer structure with graded Al composition is proposed .…”

Section: Introductionmentioning

confidence: 99%

The effective light‐harvesting performance of graded compositional Al _x Ga _1−x N nano‐cone arrays photocathode for ultraviolet detector—A numerical investigation and simulation

Liu

Zhangyang

et al. 2020

Int J Energy Res

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A graded compositional Al x Ga 1−x N nanomaterial with a built-in electric field has been proposed to improve the quantum efficiency of the negative electronic affinity photocathode. When the graded compositional Al x Ga 1−x N nano-cone array is applied to the ultraviolet (UV) detector, it is necessary to improve the effective light absorption, which is high absorption in the UV short-wavelength and high sensitivity in the threshold wavelength. Therefore, the light absorption of nano-cone arrays with different feature sizes and geometrical properties is accurately calculated innovatively based on the finite-difference time-domain method. Studies show that a non-close-packed six-sided pyramid structure with a fill factor of 42.44% and a height of 1000 nm has an absorption spectrum that better satisfies the response characteristics of the UV detector. Surface reflection depends to a large extent on the transformation of the angle of incidence. The optical absorption properties of the graded compositional Al x Ga 1−x N nano-cone array provide flexibility and reference value for the improvement of the absorption coefficient and other parameters in the actual quantum efficiency experiment of the UV photocathode with built-in electric field, which can realize the highest sensitivity of various designed UV detector optical system.

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