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Proceedings Paper

Spectral response and surface layer thickness of GaAs:Cs-O negative electron affinity photocathode
Author(s): Benkang Chang; Wenli Liu; Rongguo Fu; Yunsheng Qian; Zhiyuan Zong; Guihua Wang
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Paper Abstract

On-line spectral response curves of GaAs:Cs-O NEA photo- cathode of reflection model is first presented and the relation between spectral response curves and the thickness of Cs-O layer is discussed. When Cs and O is deposited on the surface of cleaning GaAs wafer, photo-cathode's spectral response rises sharply and long-wavelength threshold tends to a fixed value at the beginning of the activation. But, as Cs and O are deposited continually, spectral response rises slowly and the long-wavelength threshold tends to be shortened. When a fine thickness of Cs-O layer is reached, the optimum spectral response is obtained. As a quantity Cs-O is further increased, both the spectral response and the long-wavelength threshold decrease. The thickness of GaAs photo-cathode surface layer that consists of Cs-O layer and GaAs-O layer is researched by take-off angle XPS technology. Thickness of Cs-O layer is approximately equal to 0.7 nm, and the GaAs-O layer is approximately 0.2nm. Our experiments show when the thickness of Cs-O layer is approximately equal to 0.7nm, and the GaAs-O layer is approximately 0.2mm. Our experiments show when the thickness of Cs-O layer is 0.7nm or so and the GaAs-O layer tend to be disappeared, NEA photo-cathode with the optimum spectral response is achieved which can be used widely in low-light level imaging detectors.

Paper Details

Date Published: 19 October 2001
PDF: 10 pages
Proc. SPIE 4580, Optoelectronics, Materials, and Devices for Communications, (19 October 2001); doi: 10.1117/12.444934
Show Author Affiliations
Benkang Chang, Nanjing Univ. of Science and Technology (China)
Wenli Liu, Nanjing Univ. of Science and Technology (China)
Rongguo Fu, Nanjing Univ. of Science and Technology (China)
Yunsheng Qian, Nanjing Univ. of Science and Technology (China)
Zhiyuan Zong, Nanjing Univ. of Science and Technology (China)
Guihua Wang, Nanjing Univ. of Science and Technology (China)


Published in SPIE Proceedings Vol. 4580:
Optoelectronics, Materials, and Devices for Communications
Tien Pei Lee; Qiming Wang, Editor(s)

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