The field emission behavior of diamond-like carbon (DLC) films prepared by r.f plasma chemical vapor deposition (r.f.-PACVD) was investigated. DLC films were coated on p-type boron-doped Si (100) wafers using a benzene glow discharge. Nitrogen incorporated DLC films were also prepared using mixtures of benzene and nitrogen. In both pure and nitrogen incorporated DLC films, the electron emission was enhanced by electrical breakdown between the anode and the sample surface. After the breakdown, the effective work functions were measured in the range from 0.03 to 0.07 eV. The on-set electric field for emission was dependent on the breakdown behavior. We observed a minimum on-set electric held of 7 MV m(-1). The emission current was proportional to the number of damaged regions caused by the electrical breakdown. Auger electron and micro-Raman spectroscopy showed that the electrical breakdown induces the formation of defective SiC compounds in the damaged region. The improved emission behavior seems to be attributed to the chemical change of carbon in the damaged region, in addition to the field enhancement at the rough surface.