Fabrication and X-ray photoemission characteristics of Au spherical shell photocathodes

Abstract

Gold spherical shell photocathode was prepared by seed-mediated growth on polystyrefle template and dispersed on the aluminum substrates by spin-coating procedure. Polystyrefle template was then removed by heat treatment. SEM surface morphology shows that Au spherical shell of ～10 μm in diameter can be self-supported after polystyrefle substrate is removed. The thickness of Au shell is about 70-90 nm and the grain size on the surface is about 30-60 nm. X-ray photoemission characteristics of Au reflection photocathodes in the 400-1400 eV photon energy region are obtained, indicating that the Au shell photocathodes can emit 3 times more photoelectrons than the plane Au photocathode; this results from the special surface morphology of Au spherical shell and the reduction of surface potential.