Growth and Characterization of Carbon Nanowalls

摘要

A type of carbon nanoform (carbon nanowalls: CNWs) has been successfully deposited on both Ni wafers and Ni wires using dc plasma chemical-vapor-deposition (CVD) method. Transmission electron microscopy (TEM) and Raman spectroscopy were used to characterize CNWs' microstructure. It is found that CNWs are well crystallized, and each CNW consists of several pieces of curved graphene sheets, presenting a quasi-two-dimensional geometry. The average length and width of CNWs are about 2 - 4 μm, while their thickness is less than 7 nm. Field emission measurement showed that such CNW films exhibited the excellent electron emission efficiency, comparable to the high-grade carbon nanotube (CNT) emitters. The threshold field defined as the field to obtained 1 μ A/cm~2 is less than 1 V/μm and the electrical field for 1 mA/cm~2 current density is only about 1.5 V/μm. Moreover, the CNWs have stable emission behaviors, arid we have successfully fabricated a kind of high-brightness lamps based on the CNW coated Ni wires.