Field emission from tetrahedrally bonded amorphous carbon

The field emission behaviour of a series of Tetrahedrally Bonded Amorphous Carbon ta-C.films has been measured. The films were produced using a Filtered Cathodic Vacuum Arc System. The threshold field for emission and current densities achievable have been investigated as a function of sp3rsp2 bonding ratio and nitrogen content. Typical as-grown undoped ta-C films have a threshold field of order 10–15 Vrmm and optimally nitrogen-doped films exhibit fields as low as 5 Vrmm. The emission as a function of back contact and front surface condition has also been considered and shows that the back contact has only a minor effect on emission efficiency. However, after etching in either an oxygen or hydrogen plasma, the films show a marked reduction in threshold field, down to as low as 2–3 Vrmm, and a marked improvement in emission site density. q1999 Elsevier Science B.V. All rights reserved.