Shaping carbon nanostructures by controlling the synthesis process

The ability to control the nanoscale shape of nanostructures in a large-sca le synthesis process is an essential and elusive goal of nanotechnology res earch. Here, we report significant progress toward that goal. We have devel oped a technique that enables controlled synthesis of nanoscale carbon stru ctures with conical and cylinder-on-cone shapes and provides the capability to dynamically change the nanostructure shape during the synthesis process . In addition, we present a phenomenological model that explains the format ion of these nanostructures and provides insight into methods for precisely engineering their shape. Since the growth process we report is highly dete rministic in allowing large-scale synthesis of precisely engineered nanosca le components at defined locations, our approach provides an important tool for a practical nanotechnology. (C) 2001 American Institute of Physics.