Field- and photo-emission properties of CVD-diamond with different microcrystalline structure

Electron emission properties of diamond films with different microstructure s have been investigated by field- and photo-emission measurements, Both th e crystalline quality of diamond and the amount of non-diamond carbon phase s appear to largely affect the energy threshold for electron photoemission, as well as its intensity and spectral distribution, suggesting different t ypes of transition occurring below and above the diamond band gap energy. A similar dependence on the amount of non-diamond carbon phases was also fou nd for electric held threshold in field-emission measurements, where electr ic field enhancement effects related to the change of film morphology were also detected. The experimental results are discussed in terms of excitatio n of electrons out of defect states related to the diamond surface. (C) 200 1 Elsevier Science B.V. All rights reserved.