Electron field emission from sulfur-incorporated nanocrystalline carbon thin films

Results are reported on the electron field emission properties of sulfur-incorporated nanocrystalline carbon (n-C:S) thin films grown by hot-filament chemical vapor deposition technique. The lowest turn-on field values observed were around 4.0-4.5 V/μm, which are about half of those measured for films grown without sulfur. Associated to the effect of addition of sulfur on field emission properties, there are interesting microstructural changes, as characterized with scanning electron microscopy, atomic force microscopy, and Raman spectroscopy techniques. The sulfur-incorporated films show smoother and finer-grained surfaces than those grown without sulfur. These results are similar to those found for the introduction of nitrogen, but different to those produced by oxygen addition to the chemical vapor deposition process. These findings are attributed to changes in the electronic band structure.