The Establishment of C_<60> Plasma Production and Its Applications

An ultrafine-particle plasma consisting of electrons, positive K^+ ions, and large negative C_^- ions is produced by introducing "Buckminsterfullerene, C_" particles into a low-temperature (0.2eV) potassium plasma column confined by a strong axial magnetic field. When a new-type sublimation oven system with jets on four sides is used in order to control a plasma structure and achieve an efficient production of the K-fullerene plasma, K^+ and a large fraction of C_^- are observed to broadly distribute across the magnetic-field lines in contrast with well-confined electrons. With an increase in the C_^- fraction, the electron shielding decreases, yielding clear effects on plasma collective phenomena, which are demonstrated for ion-acoustic wave propagations and drift-type instabilities. It is also observed that a local production of large negative ions C_^- results in the electrostatic potential formation along the magnetic-field lines. When biases of particle-deposition substrates immersed in the plasma consisting mainly of K^+ and C_^- are varied with respect to local plasma potentials.on the other hand, K and C_ components of thin films formed are successfully controlled. In accordance with this bias control of fluxes of K^+ and C_^- ions coming into contact with the substrate, drastic changes in thin-film structure and quality such as surface roughness and electrical conductivity are observed in the formation of K-C_ compounds. The substrate bias is also accompanied by energy control of the incoming K^+ and C_^-ions. Due to this effect of selective acceleration of the ion species, K^+ with the ionic radius larger than a fullerene six-membered-ring radius is observed to be inserted into the C_^+ cage, forming an air-stable endohedral metallofullerene K@C_ on the substrate.