Polycrystalline diamond and Nd-doped diamond photoemitters

The photoemission from chemical vapor deposited polycrystalline diamond induced by 3.5 eV photons has been investigated and compared to that of Nd-doped diamond. The different behavior observed at low radiation intensity between undoped and doped diamond is shown to be due to the different excess carrier recombination rates in the two materials. The measured quantum efficiency of similar to3 X 10(-6) in the two-photon regime, at relatively low accelerating field, makes this material interesting as photoemitter.