GaAs-AlGaAs superlattice structure design for a device of an electron source

Nishitani, Tomohiro; Noritake, Yosuke*

An NEA-GaAs photocathode is expected as a high-brightness electron source satisfying the requirements of ERL-injectors. Although GaAs superlattice has been studied for polarized electron sources, the superlattice has never been applied to an ERL injector, which is usually equipped with GaAs in bulk. We propose GaAs superlattice as a photocathode for an ERL injector. The superlattice has larger NEA and larger joint density of state around band gap than bulk GaAs. These properties of GaAs superlattice will contribute to higher quantum efficiency and smaller emittance far beyond bulk GaAs. We present theoretical consideration based on Kronig-Penny model of the GaAs superlattice, and a future plan to develop the superlattice photocathode.