Effects of nitrogen addition on the structure and field emission properties of amorphous carbon

The films of amorphous carbon with different amounts of incorporated nitrog en are deposited by helical resonator plasma enhanced chemical vapor deposi tion using CH4, Ar, and N-2 gas mixtures. As the nitrogen content in the fi lms increases, the optical band gap and sp(3) bond fraction decreased. The higher field emission current and the lower turn-on voltage are obtained fr om the sample of the higher nitrogen content. The calculated emission barri er heights for a-C:N (5/5) and (10/0) are 0.76 and 0.70 times that for a-C, respectively. The increase of the conducting part of the films and the rol e of nitrogen as an electrical donor are responsible for the enhanced field emission. (C) 1999 American Vacuum Society. [S0734-211X(99)11902-4].