The influence of non-diamond carbon in diamond films on the spatial distributions of emission sites was investigated, and consequently the field emission mechanism was discussed. It was confirmed that when increasing the positive substrate bias or the CH4/H2 concentration ratio, the non-diamond carbon content in the resulting films was markedly increased and the surface morphologies of the films lost their unique facet shape. An increase of non-diamond carbon content improved significantly the field emission properties and caused a dramatic increase of emission sites. It was observed from the images of the films containing a small amount of non-diamond carbon that electron emission occurs predominantly at the sample edges and the reason for this phenomenon could be attributed to the surface electron emission. With increasing non-diamond carbon, the emission occurs at the center as well as at the edge of the sample. From this observation, it is proposed that the emission from central region was caused by a preferential transport through the conducting pathways such as grain boundaries.
Bibliographical noteFunding Information:
The authors would like to acknowledge the financial support of this work by the Ministry of Education through Contract No. 97-E-4420.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Mechanical Engineering
- Materials Chemistry
- Electrical and Electronic Engineering