Photoelectron emission form the negative electron affinity caesiated natural diamond(100) surface

摘要

The unique property of negative electron affinity (NEA) makes diamond surfaces very interesting fortechnical applications like cold cathodes and field emitters. We investigated the hydrogen-terminatedand hydrogen-free, caesiated diamond (100) surfaces by means of low-energy electron diffractionX-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. The photoemissionmeasurements permit us to determine the electron affinity and to draw the band diagrams for thesedifferently terminated surfaces. The NEA peak reappears after caesiation of the hydrogen-freesurface, whereas it vanishes after exposure to molecular oxygen. From the shift of the C 1s core level,an increasing downward band-bending of 1.2 eV was inferred following caesiation of thehydrogen-free surface and 0.6 eV following caesiation of the hydrogen-terminated surface.