title: Metal-insulator photocathode heterojunction for directed electron emission.
abstract: We use angle-resolved photoemission under ultraviolet laser excitation to demonstrate that the electron emission properties of Ag(001) can be markedly enhanced and redirected along the surface normal by the deposition of a few monolayers of epitaxial MgO. We observe new low-binding energy states with small spreads in their surface parallel momenta as a result of MgO/Ag(001) interface formation. Under 4.66 eV laser excitation, the quantum efficiency of MgO/Ag(001) is a factor of 7 greater than that of clean Ag(001), revealing the utility of such heterojunctions as advanced photocathodes.
authors.affiliation: Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Droubay
authors.affiliation: Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Chambers
authors.affiliation: Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Alan G
authors.initials: AG
authors.lastname: Joly
authors.affiliation: Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
authors.forename: Wayne P
authors.initials: WP
authors.lastname: Hess
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA and Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
authors.forename: Karoly
authors.initials: K
authors.lastname: Németh
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Harkay
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA and Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616, USA.
authors.forename: Linda
authors.initials: L
authors.lastname: Spentzouris