1 May 2006 Gradient-doping negative electron affinity GaAs photocathodes
Author Affiliations +
Optical Engineering, 45(5), 054001 (2006). doi:10.1117/1.2205171
Abstract
A variety of gradient-doping reflection-mode GaAs photocathode materials are designed and are prepared into negative electron affinity (NEA) GaAs photocathodes by (Cs,O) activation technique for the first time. These gradient-doping photocathodes are grown by molecular beam epitaxy (MBE), in which from GaAs bulk to surface doping concentration is distributed gradiently from high to low. The activation experimental results show that for gradient-doping GaAs photocathodes that are grown over p-type GaAs (100) wafer, where the epitaxial layer doping concentration range is 1019 to 1018 cm–3 and the epitaxial layer thickness is 1 µm, can achieve high integral sensitivity. The highest integral sensitivity 1798 µA/lm is achieved for gradient-doping GaAs photocathodes, which is much higher than that of a common uniform-doping GaAs photocathode under identical cleaning and activation condition. The inherent mechanism responsible for the fact that a gradient-doping GaAs photocathode can obtain higher quantum efficiency is also discussed.
Jijun Zou, Benkang Chang, "Gradient-doping negative electron affinity GaAs photocathodes," Optical Engineering 45(5), 054001 (1 May 2006). http://dx.doi.org/10.1117/1.2205171
JOURNAL ARTICLE
5 PAGES


SHARE
KEYWORDS
Gallium arsenide

Doping

Cesium

Quantum efficiency

Diffusion

Optical engineering

Molecular beam epitaxy

Back to Top