Annealing of CVD un-doped diamond: a photoemission investigation

The temperature evolution of the surface region of an undoped chemical vapour deposited (CVD) diamond film is characterized via UV and X-ray induced photoemission. Methods are proposed to diagnose and to overcome possible electrostatic charging problems connected with the poor conductivity of the film. The position of the relevant energy levels is measured and the transition from a negative to a positive electron affinity surface is observed. For the bare diamond surface, an electron affinity χ = 0.4 eV is derived while the film conductivity is shown to decrease on going from the surface towards the bul