Effect of carrier gas (Ar and He) on the crystallographic quality of networked nanographite grown on Si substrates by photoemission-assisted plasma-enhanced chemical vapor deposition

In this study, networked nanographite is formed on a Si substrate without any metal catalysts by photoemission-assisted plasma-enhanced chemical vapor deposition. We investigated the carrier gas dependence of the crystallographic quality of networked nanographite when Ar and He are used as the carrier gases. When Ar is the carrier gas, Raman spectroscopy and grazing incident X-ray diffraction show that the crystallographic quality deteriorates makedly with decreasing growth temperature, indicating that amorphous carbon is deposited at low temperatures (below ̃500 °C). On the other hand, when He gas is used as a carrier gas, a high quality nanographite can be grown even at temperatures as low as room temperature. Thus, there is a significant difference in the temperature dependence of crystallographic quality for the two carrier gases.