Absolute quantum photoyield of ion damaged diamond surfaces

We report on the absolute quantum photoyield (QPY) measurements from defective diamond surfaces in the 140-200 nm spectral range. The effect of defects on the photoemission properties of polycrystalline diamond films is studied by intentionally introducing damage using room temperature 30 keV Xe+ ion bombardment at doses ranging from 2 x 10(13) to 2 x 10(15) ions/cm(2). Ion bombardment results in a drastic degradation of the QPY, to less than 1% at 140 nm, even at the lowest implantation dose, compared to similar to 11.5% measured for the unimplanted diamond film. The decrease in QPY is associated with a change of the electron affinity from negative to positive as determined by secondary electron emission measurements. Microwave hydrogen plasma treatment of the damaged diamond films results in complete regeneration of the photoemission properties for diamond films implanted to Xe+ doses up to 2x10(14) ions/cm(2); however, only partial recovery is obtained for films irradiated with higher ion dose. (C) 2000 American Institute of Physics. [S0021-8979(00)06317-9].