Optimizing GaN photocathode structure for higher quantum efficiency

Fu, Xiaoqian; Wang, Xiaohui; Yang, Yaqi; Chang, Benkang; Du, Yu; Zhang, Junju; Fu, Rongguo

doi:10.1016/j.ijleo.2011.05.032

Cited by 15 publications

(10 citation statements)

References 15 publications

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“…Fortunately, provided that there is an electric field along with the opposite direction of photoelectron transport toward the negative electron affinity (NEA) surface, this degradation of resolution is offset to a certain extent. At this point, it should be emphasized that the exponential-doping photocathode possessing constant built-in electric field can satisfy the requirements exactly and obtain higher quantum efficiency, which has been experimentally verified [21][22][23][24][25]. As shown in Fig.…”

Section: Introductionmentioning

confidence: 77%

Resolution characteristics for reflection-mode exponential-doping GaN photocathode

Wang

Qian

et al. 2014

Appl. Opt.

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According to the expression for modulation transfer function obtained by solving the established 2D continuity equation, the resolution characteristics for reflection-mode exponential-doping and uniform-doping GaN photocathodes have been calculated and comparatively analyzed. These calculated results show that the exponential-doping structure can upgrade not only the resolution capability but also the quantum efficiency for a GaN photocathode. The improvement mechanism is different from the approach for high resolution applied by reducing Te and L(D) or increasing S(V), which leads to low quantum efficiency. The main contribution factor of this improvement is that the mechanism that transports electrons toward the NEA surface is facilitated by the built-in electric field formed by this exponential-doping structure, and the corresponding lateral diffusion is reduced.

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Section: Introductionmentioning

confidence: 77%

Resolution characteristics for reflection-mode exponential-doping GaN photocathode

Wang

Qian

et al. 2014

Appl. Opt.

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“…This possibility pushes the rapid development of advanced efficient GaN photocathodes because two times higher QE was achieved with gradient-doped GaN than with uniform-doping. 144…”

Section: Semiconductor Photocathodesmentioning

confidence: 99%

Review of photocathodes for electron beam sources in particle accelerators

2023

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“…Compound III-V semiconductors (e.g., GaAs) and alkali antimonides are the most established photocathodes offering high QEs following appropriate surface treatments at the expense of limited lifetimes. With a focus on solar blind photocathodes, there has been limited success in developing wide bandgap III-V semiconductorbased photocathodes utilizing advanced nitride materials (e.g., GaN and AlN) as well as diamond and other exotic materials [118][119][120][121] . In some cases, QEs of well over 20% have been reported for NEA treated GaN-based photocathodes under UV illumination.…”

Section: Advanced Thin Film Semiconductors and Band Gap Engineering Omentioning

confidence: 99%

“…In some cases, QEs of well over 20% have been reported for NEA treated GaN-based photocathodes under UV illumination. Various reports suggest that certain properties of GaN-based semiconductors can be tailored to enhance photoemission including band gap engineering 122,123 , doping 124,125 , utilizing inherent polarization fields 124 , nanowire structures 126 , quantum well structures 122,123 , and heterojunction schemes 119,127 . Some of these reports show promising results for limited application areas, but systematic investigations are lacking and there is limited information regarding photocathode lifetimes and no information on emittance measurements.…”

Section: Advanced Thin Film Semiconductors and Band Gap Engineering Omentioning

confidence: 99%

Perspectives on Designer Photocathodes for X-ray Free-Electron Lasers: Influencing Emission Properties with Heterostructures and Nanoengineered Electronic States

et al. 2018

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The development of photoemission electron sources to specifically address the competing and increasingly stringent requirements of advanced light sources such as X-ray Free Electron Lasers (XFELs) motivates a comprehensive material-centric approach that integrates predictive computational physics models, advanced nano-synthesis methods, and sophisticated surface science characterization with in situ correlated study of photoemission performance and properties. Related efforts in material science are adopting various forms of nanostructure (such as compositionally graded stoichiometry in heterostructured architectures, and quantum features) allowing for tailored electronic structure to control and enhance opto-electronic properties. These methods influence the mechanisms of photoemission (absorption, transport, and emission) but have not, as yet, been systematically considered for use in photocathode applications. Recent results and near-term opportunities are described to exploit controlled functionality of nanomaterials for photoemission. An overview of the requirements and status is also provided.

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Optimizing GaN photocathode structure for higher quantum efficiency

Cited by 15 publications

References 15 publications

Resolution characteristics for reflection-mode exponential-doping GaN photocathode

Resolution characteristics for reflection-mode exponential-doping GaN photocathode

Review of photocathodes for electron beam sources in particle accelerators

Perspectives on Designer Photocathodes for X-ray Free-Electron Lasers: Influencing Emission Properties with Heterostructures and Nanoengineered Electronic States

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