Field Emission Characteristics from BN-coated Diamond Films

4μm diamond films were deposited on Si by hot filament chemical vapor deposition(HFCVD),then a 100nm hexangular boron nitride(h-BN) thin films were prepared on diamond films by RF magnetron sputtering physical vapor deposition.The field emission characteristics of diamond films were tested in an ultrahigh vacuum system(10-7Pa).The field emission characteristics of the diamond films coated with the h-BN thin films were improved clearly,and the threshold field decreased from 14V/μm to 8V/μm.The Fowler-Nordheim(F-N) plots showed that the field enhancement factor decreased in the high electric field region,it could be attributed to the change of field emission sites.