Effects of ion bombardment on the morphology and microstructure of carbon nanomaterials grown by microwave plasma chemical vapor deposition

Effects of ion bombardment on the growth of carbon nanomaterials on Fe substrates in microwave plasma chemical vapor deposition were investigated. The product morphologies are directly correlated with the kinetic energy of bombarding ions and range from nanosheets, through cones, to aligned nanotubes for bias voltages from 0 to -250 V, respectively. A change in growth mechanism from a base growth to tip growth induced by the competition between etching and growth is responsible for the observed changes. These findings bring insights into the growth mechanism and provide a strong tool to control the structure of carbon nanomaterials