Js. Foord et al., An investigation of the surface reactivity of diamond photocathodes with molecular and atomic oxygen species, DIAM RELAT, 10(3-7), 2001, pp. 710-714
The surface reactivity of CVD diamond films, which function as UV photocath
odes, with thermal and electronically excited O-2 as well as atomic oxygen,
has been explored. The CVD films show a low, but measurable reactivity wit
h O-2, which increases markedly with electronic excitation, to form dilute
oxygen adlayers which are stable thermally to 800 K. In contrast, reaction
with atomic O produces significantly higher surface concentrations of oxyge
n, although these adlayers decompose thermally below 500 K,evolving CO2. Gr
eater surface reaction probabilities are observed if the diamond surface is
pre-hydrogenated before interaction with oxygen. The consequences of these
observations for the stable operation of H-terminated diamond photocathode
s are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.