Diamond films with various surface morphologies were obtained

which were deposited on pretreated molybdenum by microwave plasma-assisted chemical vapor deposition system. The films were characterised by X-ray diffraction (XRD)

Raman spectrum

optical microscopy and scanning electron microscopy(SEM). The result of expe riment indicates that diamond films with ball-like graphitic surface morohologis

which consisted of diamond nulei

were obtained. By investigating electron emission of the diamond-amorphous carbon films

we found that the lower of the size of the ball-like graphitics in diamond-amorphous carbon thin films the most efficient of electron emission.