Growth of Nanostructured Diamond, Diamond-Like Carbon, and Carbon Nanotubes in a Low Pressure Inductively Coupled Plasma

A 13.56 MHz low pressure inductively coupled CH4/CO/H-2 plasma has been applied to prepare nanocrystalline diamond particles of 200-700 nm diameter. The minimum diameter of the particles was found to be 5 nm. Two-dimensional platelet-like graphite and carbon nanotubes also were deposited with different conditions. The characterizations were performed with transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The TEM observations have revealed that the two-dimensional platelet-like deposits consist of disordered microcrystalline graphite, whereas the particles are composed of only diamond nanocrystallites. The high-resolution TEM images clearly show that each particle is composed of small particles of about several ten nm in diameter. The mapping of sp(2) bonding by the pi* image reveals that sp(2)-bonded carbons are localized in the grain boundaries of 20-50 nm sub-grains of nanocrystalline diamond particles at approximately 1 nm width.