Enhanced electron field emission properties of diamond-like carbon films using a titanium intermediate layer

Substantially improved uniformity and enhanced electron field emission properties of hydrogen-free diamond-like carbon (DLC) films were obtained using a titanium intermediate layer after the annealing process. Large emission current densities of 2.08 mA cm(-2) at 14.3 V mu m(-1) and 7.20 mA cm(-2) at 25.7 V mu m(-1) were achieved for DLC/Ti/Si film annealed at 430 degrees C for 0.5 h. Its field emission was much more uniform than that of as-prepared DLC/Ti/Si and DLC/Si films. Secondary ion mass spectroscopy (SIMS) showed that C has been amply diffused into the Ti layer. An x-ray photoelectron spectroscopy (XPS) spectrum of the annealed DLC/Ti/Si film after 10 min of argon ion sputtering showed the formation of TiC at the interface between the DLC and Ti/Si substrate. This interaction and interdiffusion of C and Ti could significantly lower the Schottky barrier height between the DLC and Ti/Si substrate. The result was that electrons induced from the Ti/Si substrate can be easily penetrated into DLC films, which enhances the field emission properties.