• J. Smedley, I. Ben-Zvi, X. Chang, P.D. Johnson, J. Rameau, T. Rao, Q. Wu
  BNL, Upton, Long Island, New York
• J. Bohon
  Case Western Reserve University, Center for Synchrotron Biosciences, Upton, New York
• E.M. Muller
  Stony Brook University, Stony Brook

The di­a­mond am­pli­fied pho­to­cath­ode has the po­ten­tial to dra­mat­i­cal­ly in­crease the av­er­age cur­rent avail­able from pho­toin­jec­tors, per­haps to the am­phere-class per­for­mance nec­es­sary for flux-com­pet­i­tive fourth-gen­er­a­tion light sources. Elec­tron emis­sion from a di­a­mond am­pli­fi­er has been ob­served from hy­dro­gen-ter­mi­nat­ed di­a­mond, using both pho­tons and elec­trons to gen­er­ate car­ri­ers. The di­a­mond elec­tron am­pli­fi­er has been demon­strat­ed, with an emis­sion gain of 40. Very high av­er­age cur­rent den­si­ties (>10 A/cm²) have been trans­port­ed through the di­a­mond using x-ray gen­er­at­ed car­ri­ers. The de­vice re­lies on high-pu­ri­ty in­trin­sic di­a­mond with low crys­talline de­fect den­si­ty, as well as a neg­a­tive elec­tron affin­i­ty achieved by hy­dro­gen ter­mi­na­tion. The ef­fects of di­a­mond pu­ri­ty and crys­talline de­fects on charge trans­port in the ma­te­ri­al, and emis­sion from the di­a­mond sur­face have been stud­ied using a num­ber of tech­niques and the pro­cess is now well un­der­stood. The elec­tron affin­i­ty of di­a­mond has been mea­sured to be -1.1 eV; the frac­tion of the elec­trons pro­duced in the ma­te­ri­al which are emit­ted from the sur­face has also been mea­sured.