Tem and Eels Investigation of a-C and ta-C Coated Field Emitters

Abstract

ABSTRACTThe microstructure of highly sp2 bonded amorphous carbon and partially tetrahedrally bonded amorphous carbon deposited on needle-shaped molybdenum field emitters by pulsed laser ablation and cathodic arc deposition techniques was studied using transmission electron microscopy and electron energy loss spectroscopy. Undoped and nitrogen-doped films were included in this study. The undoped laser ablation films were approximately 50% sp2 at the emitter tip and 65% sp2 along the shank, while the N-doped laser ablation films were highly sp2 bonded both at the tip and along the shank. These laser ablation films were continuous and relatively uniform, exhibiting an isotropie microstructure at the emitter tip and a columnar microstructure along the shank. The cathodic arc deposited films were predominantly sp2 bonded both at the tip and along the shank; these films were non-uniform, with an isotropie microstructure at the tip and regions of isotropie, columnar, and mixed microstructure appearing along the shank.