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Proceedings Paper

Photoemission stability of negative-electron-affinity GaAs photocathodes
Author(s): Tailiang Guo; Huai Rong Gao
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Paper Abstract

Photoemission stability of the negative electron affinity (NEA) GaAs-(Cs,O) photocathode activated with several cycles of alternate Cs and O2 adsorption at room temperature is mainly determined by the stabilization of the cesium and oxygen adlayer on the GaAs surface, and the bonding strength between this adlayer and the GaAs substrate. It is found that the light treatment (incident white light illumination) during or after the Cs and O2 activation process can improve the emission stability of the NEA GaAs-(Cs,O) cathodes. It is also found that the emission stability of the NEA GaAs-(Cs,O) cathodes is closely related to the electronic states of cesium and oxygen before being adsorbed on the GaAs surfaces, best result being obtained with cesium ions and excited oxygen molecules. In addition to the activation procedure and experimental results, some photoinduced reactions, e.g., photoinduced adsorption, desorption, excitation, dissociation, ionization, and surface migration and surface rearrangement of the cesium and oxygen adsorbates on or from GaAs surfaces are analyzed, and their effects on the emission stability of the NEA GaAs-(Cs,O) photocathodes are discussed.

Paper Details

Date Published: 1 April 1993
PDF: 6 pages
Proc. SPIE 1982, Photoelectronic Detection and Imaging: Technology and Applications '93, (1 April 1993); doi: 10.1117/12.142004
Show Author Affiliations
Tailiang Guo, Fuzhou Univ. (China)
Huai Rong Gao, Fuzhou Univ. (China)


Published in SPIE Proceedings Vol. 1982:
Photoelectronic Detection and Imaging: Technology and Applications '93

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