The carbon films, of which the morphology change from the carbon nanotubes to the globe-like diamond microcrystalline aggregates during the deposition, have been grown for different growing times by microwave plasma chemical vapor deposition on a ceramic substrate with a Ti buffer layer. The compositions and structures of the carbon films were evaluated by Raman scattering spectroscopy, X-ray diffraction, and scanning electron microscopy. The field emission properties were tested by using a diode structure in vacuum. The growth mechanism of the carbon films and the field emission properties of the globe-like diamond microcrystalline aggregates were also discussed and investigated, respectively. (c) 2008 Elsevier B.V. All rights reserved.