Field emission of electrons from diamond-like carbon (DLC) coated different Si surfaces is compared. Thin films of DLC were coated on smooth and rough surfaces of Si and Si micro-tips using pulsed ArF laser deposition. All DLC deposited surfaces exhibited electron emission in the electric field of 15-28 V/μm range which was lower than uncoated Si tips. The data were analyzed using the Fowler-Nordheim (F-N) theory and a contact tunneling model. The effective work function of electron emission is interpreted as due to the contact tunneling of electrons from the Fermi level of sp² clusters to the conduction band of sp³ clusters. Analysis also shows that the low work function (several hundred meV) of DLC coated flat Si surfaces deduced from the F-N analysis is far deviated from the real situation.