Spatial variation of field emission current on nitrogen-doped diamond-like carbon surfaces by scanning probe method

摘要

Field emission characteristics of nitrogen-doped diamond-like carbon (DLC) films deposited by the radio frequency plasma enhanced chemical vapor deposition (rf-PECVD) method were investigated by the scanning probe system specially designed for the micro-scale field emission current measurements. The structural changes in the films were examined by using Raman spectroscopy. Random and inhomogeneous distribution of electron emission sites was observed. The emission current and conductivity of the filets were significantly increased with self-bias voltage. Activated electron emission characteristics were observed in all samples and showed stable electron emission. The activation of the films was directly related to emission site size. It indicated that electron emission activation possibly originated from the changes in sp~2 and sp~3 bonding ratio and/or formation of conductive channels.