Atomic hydrogen cleaning of polarized GaAs photocathodes

Maruyama, T.; Luh, D.-A.; Brachmann, A.; Clendenin, J. E.; Garwin, E. L.; Harvey, S.; Kirby, R. E.; Prescott, C. Y.; Prepost, R.
June 2003
Applied Physics Letters;6/9/2003, Vol. 82 Issue 23, p4184
Academic Journal
Atomic hydrogen cleaning followed by heat cleaning at 450 °C was used to prepare negative-electron-affinity GaAs photocathodes. When hydrogen ions were eliminated, quantum efficiencies of 15% were obtained for bulk GaAs cathodes, higher than the results obtained using conventional 600 °C heat cleaning. The low-temperature cleaning technique was applied to thin strained GaAs cathodes used for producing highly polarized electrons. No depolarization was observed even when the optimum cleaning time of about 30 s was extended by a factor of 100.


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