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Improved lifetime of a high spin polarization superlattice photocathode.
- Source :
-
Journal of Applied Physics . 3/31/2020, Vol. 127 Issue 12, p1-8. 8p. 2 Diagrams, 1 Chart, 6 Graphs. - Publication Year :
- 2020
-
Abstract
- Negative Electron Affinity (NEA) activated surfaces are required to extract highly spin-polarized electron beams from GaAs-based photocathodes, but they suffer extreme sensitivity to poor vacuum conditions that results in rapid degradation of quantum efficiency. We report on a series of unconventional NEA activations on surfaces of bulk GaAs with Cs, Sb, and O 2 using different methods of oxygen exposure for optimizing photocathode performance. One order of magnitude improvement in lifetime with respect to the standard Cs – O 2 activation is achieved without significant loss of electron spin polarization and quantum efficiency by codepositing Cs, Sb, and O 2. A strained GaAs/GaAsP superlattice sample activated with the codeposition method demonstrated similar enhancement in lifetime near the photoemission threshold while maintaining 90% spin polarization. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00218979
- Volume :
- 127
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- Journal of Applied Physics
- Publication Type :
- Academic Journal
- Accession number :
- 142515568
- Full Text :
- https://doi.org/10.1063/1.5139674